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ASME Conference Presenter Attendance Policy and Archival Proceedings

2017;():V014T00A001. doi:10.1115/IMECE2017-NS14.
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This online compilation of papers from the ASME 2017 International Mechanical Engineering Congress and Exposition (IMECE2017) represents the archival version of the Conference Proceedings. According to ASME’s conference presenter attendance policy, if a paper is not presented at the Conference by an author of the paper, the paper will not be published in the official archival Proceedings, which are registered with the Library of Congress and are submitted for abstracting and indexing. The paper also will not be published in The ASME Digital Collection and may not be cited as a published paper.

Commentary by Dr. Valentin Fuster

Emerging Technologies: Alternative Fuel and Renewable Energy Technology

2017;():V014T07A001. doi:10.1115/IMECE2017-70043.

Everyday millions of drivers pull on to the interstate and drive speeds up to and beyond 70 miles per hour. This process can take a lot of energy to overcome the air resistance. As a vehicle progresses along the interstate the air must move out of the way in order to make room for the passing vehicle. The air then tries to refill the void after the car has passed by rushing back into the space that the car just occupied. To a by-stander on the side of the road, this process would feel like a gust of wind had just blown past them. It is the purpose of this group to harness the power of this wind created by these passing vehicles.

The process of design led to a turbine being placed four feet away from the passing vehicle and three feet high. The turbine used to create power from the wind is a Savonius turbine design due to its vertical axis and higher starting torque. The starting torque due to a passing vehicle was calculated by running computational fluid dynamics simulations in the state-of-the-art SolidWorks Flow Simulation software. Two external flow simulations were performed: one with a car and a wind turbine at the side of the road, and the other with a wind turbine only at the side of the road. The differences in torques calculated in these two simulations gave the torque due to the vehicle on the wind turbine. From the starting torque we found the angular accelerations and then, through kinematic relations, power of the turbine was calculated as a function of time. A power profile curve was generated over 3 seconds, assumed to be an average period the turbine would experience the wind from passing vehicles at a time. If multiple vehicles pass by the turbine one after another this time period will be lengthened. Forces from the wind on the wind turbine were also calculated and finite element analysis was performed to ensure structural integrity of the turbine structure. The generated power can be used in many ways, such as to light up street lights along the interstate and local road ways for vehicles to drive safely at night with less power taken from the city’s power grid. This concept can also be applied to passing trains to power sign boards, lights or maybe even the trains themselves.

Commentary by Dr. Valentin Fuster
2017;():V014T07A002. doi:10.1115/IMECE2017-70331.

In Romania, near the Black Sea are two Natural Reservations lakes with salt water, Techirghiol, and Mangalia nowadays confronted with new environmental issues. Lake never freezes. Under these conditions, there are always birds in transit or in wintering; some of them protected species as endangered. There are no known or available solutions at present that can be used here, without disturbing the biological balance. This paper presents a prototype, patent pending in Romania, which has achieved significant results in protection of the natural environment. The prototype is an autonomous pilot station, placed on a mobile pontoon, powered by photovoltaic panels. It can collect and partially dry the aquatic vegetation developed in excess due to eutrophication. The harvested vegetation is used as the biomass resource to warm the Research Centre on shore, the greenhouse for the protected plant species and the poultry incubator. The prototype now is implemented in Techirghiol Lake as to diminish the local environmental problems: the massive mass of vegetation, the invasive species that appeared, as the invertebrates, the interference scallops, and the predator fish. Due to the permanent decreasing the number of the specific fish, all bird colonies are affected. The proposed solution is innovative, perfect ecological and energetic independent. The mobile pontoon is commanded from distance. The solar panels ensure the pontoon movement and the supply of the collecting, compacting, and partially drying the vegetation. The detailed functioning of the prototype is further detailed presented. The main advantage of this solution is that the vegetation can be collected during the entire period of vegetation without disturbing the biologic environmental, nests period of construction, laying eggs, rearing birds, etc. A second major advantage is that the extracted vegetation can be consumed immediately and integrally into a biomass power plant. The third advantage of this technology is that the platform is placed on a mobile pontoon energetically independent, entirely automated and with a constant adaptation of the operating parameters in accordance with climatic conditions. This innovative solution is accordance to the Romanian reply for EU Council Directives, UE EUCO 75/13 CO EUR 7 signed in Brussels at 22/05/2013, referring to the promotion of the new solutions based on utilization of renewable technology with environmental effects. The prototype has a multi- and a cross-disciplinary character due to the main components. It represents a powerful applicative research requested and co-financed by the National Authorities and the private sector, as to solve this problem appeared into these Natural Reservations.

Topics: Biomass , Lakes
Commentary by Dr. Valentin Fuster
2017;():V014T07A003. doi:10.1115/IMECE2017-72381.

This paper investigates the use of hydrogen along with natural gases and solar energy to power a 50 MW power plant in the United Arab Emirates. Sudden changes in the climate have shifted the focus of scientists to formulate solutions to global warming and environmental pollution. Hence, numerous researches are being carried out on various renewable energy sources, such as solar energy and hydrogen. This study examines how the power generation, carbon dioxide (CO2) emission and the fuel consumption of the power plant is affected by the use of hydrogen, solar energy and natural gases. The power plant under investigation consisted of a hybrid conventional combined cycle whose bottoming cycle was allocated for the production of hydrogen during the day. The hydrogen that was produced was used at night to power the topping cycle to generate electricity. Solar energy was captured through concentrated solar power technology, while hydrogen was produced by a water electrolysis process. An extensive investigation of the performance of the power plant revealed that its annual hydrogen share was 7%, solar share 20% and natural gas share 73%. In addition, the annual CO2 emission and fuel consumption was found to be 394.1 kgCO2/MWhe and 58412 tonne respectively.

Topics: Design , Hydrogen
Commentary by Dr. Valentin Fuster

Emerging Technologies: Emerging Applications of 3D Printing

2017;():V014T07A004. doi:10.1115/IMECE2017-70144.

Additive manufacturing technology is a process of joining materials to make objects from 3D model data, usually layer upon layer, contrary to conventional manufacturing technologies, which mostly use subtractive process. The technology has developed from the earlier days of rapid prototyping to sophisticated rapid manufacturing in the last 20 years and can create parts directly from CAD model without the use of tooling. This technology is predicted to revolutionize many sectors of manufacturing by reducing component lead-time, material waste, energy usage, etc. Though there is significant progress in the field, there are still a number of challenges including characterization of mechanical properties. This paper presents a study conducted to characterize the mechanical properties of ABS-M30 materials whose specimens are fabricated using different printing parameters. To understand the mechanical properties, it is vital to study the effects of the printing parameters on 3D printed parts. For this purpose, Design of Experiment (DOE) is used. The printing parameters of the machine (Fortus 450mc Fused Deposition Modeling (FDM) machine) such as raster orientation, air gap, and raster width, were examined to test Tensile strengths and 3-point bend strength of the tested specimens. The study shows that, raster orientation and air gap has more effect on mechanical properties of ABS-M30 products where raster width has less effect.

Commentary by Dr. Valentin Fuster
2017;():V014T07A005. doi:10.1115/IMECE2017-70263.

Medical models are physical models of human or animal anatomical structures such as skull and heart. Such models are used in simulation and planning of complex surgeries. They can also be utilized for anatomy teaching in medical curriculum. Traditionally, medical models are fabricated by paraffin wax or silicone casting. However, this method is time-consuming, of low quality, and not suitable for personalization. Recently, 3D printing technologies are used to fabricate medical models. Various applications of 3D printed medical models in surgeries and anatomy teaching have been reported, and their advantages over traditional medical models have been well-documented. However, 3D printing of medical models bears some special challenges compared to industrial applications of 3D printing. This paper reviews more than 50 publications on 3D printing of medical models between 2006 and 2016, and discusses knowledge gaps and potential research directions in this field.

Commentary by Dr. Valentin Fuster
2017;():V014T07A006. doi:10.1115/IMECE2017-70344.

Ceramic materials are more difficult to process than metals and polymers using additive manufacturing technologies because of their high melting temperature, high hardness and brittleness. Binder jetting additive manufacturing has been used to fabricate ceramic parts for various applications. This paper presents a literature review on recent advances in ceramic binder jetting. The paper begins with listing applications and material properties investigated in reported studies followed by the effects of raw materials and process parameters on resultant material properties. Raw materials include binder (material, application method, concentration, and saturation) and ceramic feedstock (preparation method, quality metrics, and particle size and shape), and process parameters include layer thickness and postprocessing method. Resultant material properties of interest include density, strength, hardness, and toughness. This review will provide guidance for the selection of raw materials and process parameters to obtain desired material properties for various applications. This paper is concluded by proposing future research directions.

Commentary by Dr. Valentin Fuster
2017;():V014T07A007. doi:10.1115/IMECE2017-70349.

This paper discusses the design and manufacturing of the Universal Expanding Cage (UEC), which is a biomechanical device that is implantable in the human spinal cord region. It compensates for disc height loss and relieves pressure that causes nerve damage. Forces surrounding the UEC are analyzed, stresses on the UEC body and resulting displacement are calculated, and materials suitable for the human biological vertebra environment are studied. Manufacturing methods for implantable UEC are also discussed using 3D direct metal print technique.

Topics: Manufacturing , Design
Commentary by Dr. Valentin Fuster
2017;():V014T07A008. doi:10.1115/IMECE2017-71252.

A cast is used to encase a limb or part of the body to stabilize and hold anatomical structures in place to allow healing of broken bones and ligament tears by promoting immobilization. Conventional orthopedic casts have been made out of Plaster of Paris or fiberglass since ages. The traditional plaster casts have a wide range of problems that have been long since evaded due to the lack of a better alternative. Ever since the advent of additive manufacturing, many remarkable things have been made possible by the technology of 3D printing. The Exoskeletal Immobilizer is a custom 3D printed orthopedic cast that is well ventilated, light weighted, aesthetically pleasing and anatomically accurate. Even though printing the immobilizer on spot takes a little longer than the conventional cast, its countless benefits make up for the waiting time. It is extremely logical and useful for the ones suffering from cerebral palsy, who are forced to wear casts for their entire life. This project is not just another profit making business idea but is the cornerstone that is being laid to serve the people better and lead humanity into the next phase of medical advancement. By integrating parts of physiotherapy, eastern medicine, orthopedics and latest technologies, the Immobilizer promises a speedy recovery. The possibility of performing ultrasound therapy, electrical stimulation therapy, chromotherapy, cryotherapy and acupuncture therapy during the immobilization period reduces the healing time at least by about 40% [4] and eases discomfort of the patients. The features imparted to the cast have been specially handpicked and researched to provide a safe overlap of post immobilization treatment and the immobilization period to facilitate faster healing. The Exoskeletal Immobilizer can not only heal the fracture or a tear faster but can also keep the patient comfortable during the treatment.

Commentary by Dr. Valentin Fuster
2017;():V014T07A009. doi:10.1115/IMECE2017-71534.

Metal Additive Manufacturing (MAM) has had a tremendous impact in reimagining the design and manufacture of products in a number of industries. The use of MAM to directly produce products continues to be investigated; however, the area of manufacturing tooling has yet to be fully explored. MAM provides a unique opportunity to introduce features that make manufacturing tooling better equipped to efficiently produce complex products. A recent example includes MAM produced molds for the injection molding industry. MAM, in this case, provides the ability to introduce unique features, such as cooling channels, that could not be introduced practically with SM processes. This study explores the use of MAM towards the engineering and design of Extrusion Die Tooling for plastic extruded products. Plastic extrusion is a high-volume manufacturing process for a broad range of products from tubing to window frames. These extruded plastic products come in not only a range of sizes, but also different polymer materials. A series of extrusion dies are currently needed in the process in order to achieve the final shape of the product. These dies are effectively designed in two dimensional Computer Aided Design (CAD) packages, because of the current preferred method of fabrication, wire Electrical Discharge Machining (EDM). This study explores the effect of MAM on the extrusion die engineering design process. The explored cases center on common extruded plastic products including tubing and constant wall U-channels. The study first describes how sets of extrusion dies are currently designed in CAD in order to produce the desired extruded product features with established advanced manufacturing processes (EDM). The study then details the effect of using the MAM alternative on the design process, CAD methods selected, and the extrusion die features. The impact of MAM on the extruded die design process are discussed in order to provide guidelines for when it should be considered in order to effectively achieve features on the described extruded plastic products.

Commentary by Dr. Valentin Fuster
2017;():V014T07A010. doi:10.1115/IMECE2017-71815.

The development of gene therapies, small molecules and nanoparticle-based therapeutics in pharmacology have prompted the need for parenteral administration as they possess limited bioactivity, low stability, high specificity and potency. The ability to directly deliver drugs to a specific area offers the capability of minimized required drug quantity, localization of exposure, and limited systemic side effects. Currently, there is no standard for the creation of implantable devices to monitor health status and provide therapeutic treatment. We explored the applications and uses for carbon nanotube based arrays for in vivo drug delivery, specifically as an implantable reusable mode of delivery. The increased availability of 3D printing allows for not only the rapid and reproducible fabrication of designs, but also the ability to incorporate these carbon nanotube arrays in ways that are not feasible using traditional machining methods. These techniques offer the means to design and fabricate a reservoir on carbon nanotube arrays to create a loadable reservoir that can regulate flow, dispensing cargo for mass cellular injection. This research focuses primarily on the development of an attachable drug reservoir for these devices and looks to explore the possibilities of designing reservoirs made out of biocompatible 3D printed materials such as plastics, alloys, or bioceramics. We explored several routes, including a rigid and semi-rigid, as well as how each design impacted the flow through the membrane.

Commentary by Dr. Valentin Fuster
2017;():V014T07A011. doi:10.1115/IMECE2017-71852.

Template based chemical vapor deposition (CVD) is a process of effectively fabricating nanostructures such as Carbon nanotube arrays (CNT). During this process, a carbon-carrying precursor gas is used to deposit a layer of solid carbon on the surface of a template within a furnace. Template-based CVD using porous anodized aluminum oxide (AAO) membranes as the template has been applied to efficiently mass-produce CNT arrays which have shown promise for use in gene transfection applications. These AAO membranes are incredibly fragile, making them prone to cracks during handling which can compromise their performance. In order to ease handling of the CNT devices, three-dimensional (3D) printing has been applied to create a support structure for the fragile membranes. The work presented here focuses on the use of 3D printing as a means of integrating CNT arrays into nanofluidic devices, both increasing their useful application and preventing damage to the fragile arrays during handling. 3D printing allows the CNT arrays to be completely encapsulated within the fluidic device by printing a base of material before inserting the arrays. Additionally, 3D printing has been shown to create an adequate seal between the CNT arrays and the printed device without the need for additional adhesives or sealing processes. For this work, a commercially available, fused deposition modeling (FDM) 3D printer was used to print the devices out of polylactic acid (PLA) plastic. This approach has been shown to be effective and repeatable for nanofluidic device construction, while also being cost effective and less time consuming than other methods such as photolithography. Cell culture and has been demonstrated using HEK293 cells on the devices and was found to be comparable to tissue culture polystyrene.

Commentary by Dr. Valentin Fuster

Emerging Technologies: Innovative Products

2017;():V014T07A012. doi:10.1115/IMECE2017-70026.

Military diving operations are routinely conducted in what can be one of the most inhospitable environments on the planet, frequently characterized by zero visibility. The inability to clearly see the immediate operational environment has historically been a serious limitation to manned diving operations — whether the mission is ship husbandry, under water construction, salvage, or scientific research.

U.S. Navy diving is an integral part of the nation’s defense strategy with a continuing requirement to conduct manned intervention in the water column. To ensure technical superiority across the entire spectrum of diving operations we must identify, exploit, and de velop technology to advance the state-of-the-art in diving equipment. This can only be achieved by investing in, and supporting, focused research and development with specific goals to further diving capabilities.

Under a project sponsored by the Office of Naval Research (ONR) and Naval Sea Systems Command (NAVSEA), the Naval Surface Warfare Center-Panama City Division (NSWC PCD) has de veloped a prototype see-through head-up display system for a U. S. Navy diving helmet — the Divers Augmented Vision Display (DAVD). The DAVD system uses waveguide optical display modules that couple images from a micro display into a waveguide optic, translate the images through a series of internal reflections, finally exiting toward the diver’s eye providing a magnified, see-through virtual image at a specific distance in front of the diver. The virtual images can be critical information and sensor data including sonar images, ship husbandry and underwater construction schematics, enhanced navigation displays, augmented reality, and text messages.

NSWC PCD is the U.S. Navy’s leading laboratory for research, development, testing, evaluation, and technology transition of diver visual display systems; with unique facilities for rapid prototyping and manufacturing, human systems integration and extreme environment testing. Along with NSWC PCD, the Navy Experimental Diving Unit (NEDU), and Naval Diving and Salvage Training Center (NDSTC) are co-located tenant commands at the Naval Support Activity Panama City (NSA PC).

This paper provides a brief background on the development of diver head-up display systems, waveguide optical display technology, development of the DAVD prototype, results of diver evaluations, and recommendations for accelerated development of this game changing capability.

Commentary by Dr. Valentin Fuster
2017;():V014T07A013. doi:10.1115/IMECE2017-70524.

The paper shows an idea of a new type of mechanical gear — the eccentric rolling transmission. The main parts of that transmission are rolling bearings, mounted eccentrically on the input shaft which cooperate with the special-shaped cam wheels mounted on the output shaft. The number of rolling bearings is equal to the number of cam wheels. On the basis of kinematic analysis equations of the curve which describe a shape of cam wheels were determined for two different cases: in the first one the directions of shafts rotations were opposite, and in the second they were the same. Kinematic analysis of the novel transmission was carried out to determine maximum gear ratio depending on the adopted input parameters. As a result of analyses a design procedure of the eccentric rolling transmission and CAD model were prepared.

Commentary by Dr. Valentin Fuster
2017;():V014T07A014. doi:10.1115/IMECE2017-70525.

The paper presents the theoretical bases, design and the principle of operation of two-stage precession type transmission with face meshing. Description and the principle of forming the face meshing which is modified by the original method have been shown as well. Dimensional relations between particular components of the gears are established and the analysis of optimal gear ratio, depending on the number of teeth or magnets on the circumferences of meshing gear wheels is also provided in the paper.

For further analysis four prototypes of mechanical precession transmission with face meshing were designed, built and investigated. Those prototypes present different sizes, reduction ratio and precession angle. Investigations, described in the paper, helped to determine the gear efficiency rate as well as the maximal torque that could be transferred for the given rotary speed.

This paper presents also the conception of the design of a novel double stage precession magnetic gear with face neodymium magnets. The results of the initial studies are the background of the further research in the field of magnetic precession type transmission.

Commentary by Dr. Valentin Fuster
2017;():V014T07A015. doi:10.1115/IMECE2017-70588.

Disposable cups tend to be a viable solution as a packaging method for hot or cold beverages, but they have adverse environmental impact. They represent a concern for consumers due to the excessive use of trees during production of paper cups and non-biodegradability of plastic cups. The mobility and convenience of reheating the beverage in a microwave oven, for example, encourages the use of disposable cups. In this project, an environmentally-friendly solution is presented to reduce the use of plastic and paper cups that harm the environment. Compared to other existing products, this device maintains a desired temperature of a hot or cold beverage for extended periods of time using insulation and power from a thermoelectric cooler. The proposed design consists of a double-wall mug with outer steel and inner copper cylinders. The base of the copper cylinder is integrated with a thermoelectric cooler and a control system. The development of the device is governed by the performance of preserving desired temperature of beverages for longer times compared to conventional mugs and containers. Testing methods consist of thermal FEA simulation, CFD simulation and physical prototype testing showing a temperature difference of 30 °C with the added thermal system to the mug.

Commentary by Dr. Valentin Fuster

Emerging Technologies: Mechatronics and Automation

2017;():V014T07A016. doi:10.1115/IMECE2017-70475.

In current study, a hybrid mesoporous material infused with metallic oxide nanoparticles, MCM-48 with TiO2 nanoparticles, has been developed for potential application in water treatment. Using this unique hybrid structure, it can combine the advantages of the effective pollutants removal capability of metallic oxide nanoparticles, and the strong yet high permeable structure of mesoporous material. A modified hydrothermal method has been developed to synthesize three hybrid samples with TiO2 nanoparticles of three assorted sizes (15, 50 and 300nm), and their structure have also been characterized. The synthesized samples are tested for its capability of removing organic dye and trace metals using ICP-MS. The results have shown that while all three hybrid materials have shown over 80% adsorption rate for organic dye, the sample synthesized using 300nm TiO2 nanoparticle has shown the highest adsorption rate. Similarly, the highest adsorption rate for most trace metals test here also occurs in the sample made with 300nm TiO2 nanoparticle. Coincidentally, the sample prepared with 300nm TiO2 nanoparticle has a much larger internal surface area and smaller average pore size compared to the two other samples, which may lead to the higher adsorption rate of trace metals and organic dye tested here. This study has presented a hybrid mesoporous material that can be potentially used for pollutants removal of water treatment. Future studies are still needed to fully explore this hybrid material and its capability in water treatment.

Commentary by Dr. Valentin Fuster
2017;():V014T07A017. doi:10.1115/IMECE2017-70735.

Automation industries are trying to integrate and consolidate the operation of various processes that make up their production line. Most often, every one of those processes is controlled by unique controllers and hardware as the process demands. Each of these independently controlled units can be seen as “islands of automation”. It is indeed a challenge for the control engineer to ensure smooth communication between these islands. The challenge gets magnified many fold when the plant performs troubleshooting, maintenance, or an upgrade. Compatibility over time, between components that make up the line can never be guaranteed in today’s world dominated by software drivers where improvements and upgrades are frequent. It is generally agreed in the industry that controllers and software consolidation should be done as much as possible. In this paper, the authors would like to discuss the case of integration of two such islands of automation, i.e. motion control (traditional single axis control of servos) and robotics. Automation integrators working on applications such as packaging, converting, palletizing etc. use a combination of robots and independently acting servos to achieve their objective. Programming software and programming methods for these two elements have been quite different. There has been a push in the automation industry to consolidate the control programming of motion components and robots because the underlying control techniques that actuate motion are the same. However, there are challenges that must be overcome in order to ensure that this push brings about useful and substantial changes that reduce control programming, maintaining and troubleshooting efforts. Such challenges are listed in this paper. Potential solutions to overcome these challenges are also laid out in this work.

Commentary by Dr. Valentin Fuster
2017;():V014T07A018. doi:10.1115/IMECE2017-71861.

Holonomic motion is desired for mobile ground robots and vehicles as it provides omnidirectional maneuvering capabilities, which can simplify the task of navigating around obstacles in confined spaces and unstructured environments. Mobility platforms that utilize spherical wheels are gaining popularity and interest due to the agile maneuvering and ground traversal capabilities they enable for mobility platforms. Ball-driven mobility platforms have a rich design space as various design parameters are available that can modify the physical and performance characteristics of the platforms. Various configurations for ball-driven mobility platforms are presented along with a generalized kinematic model that can be used for calculating motor velocities for a desired vehicle velocity. A naming convention is also presented in the paper for differentiating between configurations used for ball-driven mobility platforms. Metrics such as platform footprint, platform stability, and actuation force and efficiency are used to compare the configurations and to highlight some of the trade-offs associated with the selection of a configuration. Promising configurations are highlighted based on the metrics selected for the comparisons.

Commentary by Dr. Valentin Fuster
2017;():V014T07A019. doi:10.1115/IMECE2017-72076.

Recent advancements in robotics have established standard control and planning algorithms for robot localization, navigation, and manipulation, which extend the automation from skill-based to rule-based. Such automation approaches, however, are susceptible to environmental dynamics and the burden of corresponding event handling falls on the human operator. In multi-agent systems, any deviation from the otherwise inefficient one operator to one robot mapping can result in an exponential growth of system complexity, and, in the absence of some form of artificial intelligence supervisory control, the overall framework can quickly become unmanageable, counterproductive, and even hazardous. Therefore, for future manned-unmanned teaming, a knowledge-based cooperative control architecture is warranted that can process cognitive reasoning at the meta-level to autonomously carry out some or all tactical parts of the mission while maintaining constant connection with the human operator. Furthermore, in such a scenario, the human operator needs to be able to communicate with multiple robotic agents via natural language and gesture interface so that he/she can efficiently manage not just one robot but the entire swarm or at least a segment. This paper will discuss a hybrid swarm autonomy architecture to coordinate a diverse team of robots using an immersive and intuitive interface technology for cooperative control of unmanned platforms. This novel interactive interface will offer situational awareness and decision presentation capabilities. Implemented through a real time, networked, mixed reality environment, it will be designed to support rapid exploration and evaluation with the swarm as well as dynamic interaction among different human operators. One of the major objectives of this research is to reduce cognitive load on operators and enable trust among robots and humans. This paper will discuss the approach to design and evaluate a distributed trust control algorithm for high-throughput hybrid swarm autonomy, and implement it through a curated, controlled-access portal to integrate swarm algorithms and collective behavior. Major discussion points will include: customization of unmanned platforms for distributed control and sensor fusion, development and implementation of a mixed reality human robot interface portal, and incorporation of a neuro-cognitive dynamic trust controller for swarm autonomy. It is envisioned that through such interconnection between humans and robots the effectiveness of the swarm can be boosted to carry out the missions with unprecedented speed and accuracy at a fraction of the cost for complex systems. This paper presents experimental validation to the analytical models involving real and virtual platforms.

Commentary by Dr. Valentin Fuster
2017;():V014T07A020. doi:10.1115/IMECE2017-72393.

Energy pipelines require regular inspection and health monitoring against defects, cracks, and corrosion due to the fluid pipe interaction and external environment conditions. Accurate and efficient pipeline inspection is extremely important to the oil and gas industry. Inspection of pipelines is usually carried out either internally using smart pigs and tethered robots or externally with limited inspection options. Internal inspection has many limitations and external inspection is still primitive. However, external inspection has the advantage of being carried out without interruption of the production process. In this paper, a novel design for an autonomous robot for pipeline external inspection is presented. Although, the proposed design is developed mainly to fit a magnetic flux leakage based inspection technique, the robot modular design will fit other inspection methods and applications with minimal design modifications. The proposed robot is designed to carry multiple hall effect sensors and allow adjustment of the radial distance between the sensors and the pipe surface. Also, the robot is able to scan different size pipes and maintain constant distance from the pipe surface. A prototype is fabricated using 3D printer and standard fasteners to evaluate the workability of the proposed design. The initial testing of the developed prototype showed that the robot can be made to move at a constant speed without slipping. The design details and the prototype elements are delineated in this paper.

Commentary by Dr. Valentin Fuster

Emerging Technologies: Trends in Energy Efficiency and Management, Carbon Management

2017;():V014T07A021. doi:10.1115/IMECE2017-70149.

Through design thinking, a team of researchers and students from Nigeria, Ghana and Germany has identified rural transportation as a key enabler for addressing the most pressing challenges in the developing world. Since 2013, the team has been working together on designing a new vehicle concept for Sub-Saharan Africa.

The aim of the project is to provide the rural population in Sub-Saharan Africa with an attractive mobility concept that helps to prevent the rural exodus and strengthens the independence of the rural regions. A promising concept must consider the specific market requirements and the resources available locally in order to address the heart of the problem as a “First Mile Vehicle”.

This paper aims to introduce a holistic framework for frugal innovation and to analyze the process of deriving the vehicle concept meeting regional requirements until it is ready for serial production. The focus, therefore, is demand-driven development of a multifunctional electric vehicle that primarily provides mobility for the individual and transport of people and goods as a possible commercial basis.

The result of the research and design process is a vehicle concept that meets the needs of the people living in rural areas of Sub-Saharan Africa. The first fully functional prototype of this vehicle was presented to the public at the Technical University of Munich in May 2016.

Topics: Vehicles
Commentary by Dr. Valentin Fuster
2017;():V014T07A022. doi:10.1115/IMECE2017-71297.

Solar car racing has created a competitive platform for research into alternative energy solutions and aids development in the green engineering space. The University of Johannesburg’s Solar Racing team developed a vehicle (Ilanga II) to compete in the 2014 South African Solar Car Challenge. This paper describes the numerical optimization of the vehicle’s body shape, utilizing Computational Fluid Dynamics (CFD) and finally compares the simulated results with the actual performance during the race. Motor control data is used to determine the aerodynamic drag coefficient of the vehicle. This work builds on the paper submitted in 2014 [1], which postulated the use of the Hermite cubic function in conjunction with the shape function analysis as a holistic design tool. By analyzing the motor control data it is possible to comment on the effectiveness of the shape function analysis technique. The final optimized design predicted a straight-line ACd 0.078. A yaw angle characterization study of ±25° degrees, in conjunction with historic weather data were used to fully characterize the vehicle with an average drag area coefficient of 0.119. The final comparative results of the simulated data and the race data show that the vehicle’s straight-line (Zero yaw) ACd was 11.2% higher than the simulated results, whereas the average aerodynamic characteristic ACd was 2.43% lower than the simulated results.

Commentary by Dr. Valentin Fuster
2017;():V014T07A023. doi:10.1115/IMECE2017-71325.

Diesel exhaust particulate matter (PM) is deadly to humans, animals and plants so the future of diesel engine is uncertain. Alternative powered vehicles have major limitations and costly. Recent developments to limit PM emissions have significant disadvantages to the point where they cannot be considered to be reliable long term technical and economical solutions. Electrostatic filtration could be used together with existing filters or as a standalone system. The most popular method of decreasing PM emissions is by the use of ceramic diesel particulate filters which is not efficient at filtering ultrafine particulates. Electrostatic filtration is a promising approach which can capture ultrafine particulates which could be used in conjunction with ceramic DPFs, metallic flow through filters (FTF) or, ideally as a standalone system. Development of prototype electrostatic diesel particulate filtration systems (EDPS) requires reliable testing. Prototyping needs quick, repeatable and affordable results to validate theories and a solution had to be developed. This paper presents the development of the EDPS prototype testing procedures and equipment with preliminary test results. By repurposing proven test equipment for the use of exhaust sampling, a test rig and a repeatable procedure for testing prototype filters were developed with low initial and ongoing costs.

Commentary by Dr. Valentin Fuster
2017;():V014T07A024. doi:10.1115/IMECE2017-71417.

Global trends indicate that energy consumption in manufacturing automation is an important aspect to support next generation of sustainable eco-factories. Some manufacturing processes consume large amounts of energy to fully be automated. Researchers have been emphasizing the significant challenge energy generation will be in coming years to fulfill demand. Therefore, there is a need to explore new ways of reducing manufacturing automation energy consumption. This paper focuses on research concerned with energy consumption in a fully integrated manufacturing automation, and argues that the understanding of different approaches to explore novel tools for sustainable manufacturing is important to support eco-factories.

Commentary by Dr. Valentin Fuster

Materials: Genetics to Structures: Bioinspired Materials and Structures

2017;():V014T11A001. doi:10.1115/IMECE2017-70770.

Application of 3D printing to works of art is not new. However, with the advent of larger and more affordable 3D printers, it is possible to fabricate works of art including statues, sculptures, and architectural structures from biomimicked composites. Made of hard ceramic and soft polymer with or without reinforcement, these composites have shown to be much tougher than their monolithic counterparts. The use of biomimicking will increase the durability and strength of such artifacts. In this study, a newly developed architectural 3D printer is used to create works of art using concrete, with and without reinforcement fibers. The challenge that face creating tough artistic display structures include durability, hardness and resistance to impact. To determine the right combination of hard ceramic and soft polymer, a series of experiments were conducted. These included the fabrication of biomimicked composites with different materials and testing them for fracture energy as well as maximum strength. Earlier published works demonstrate the effect of various parameters such as type of ceramic layer, layering, fiber reinforcement type, fiber length, and fiber loading. In this paper, the effect of hard layer thickness and the type of polymer on the mechanical properties of the biomimicked composites was investigated. Preliminary results show the highest fracture energy for composites made with concrete bonding adhesive (CBA) and Quikrete™ concrete, with a spacing of 5mm. The application of 3D printing to the educational activities of a museum in Newport KY will be explained and its implication in relation with civic engagement activities of Northern Kentucky University will be elucidated.

Commentary by Dr. Valentin Fuster

Materials: Genetics to Structures: Congress-Wide Symposium on Additive Manufacturing: Structure-Property Modeling and Characterization

2017;():V014T11A002. doi:10.1115/IMECE2017-70452.

Silicon Carbide (SiC) and Carbon filled PLA Composite filaments made for use with Fused Deposition Modeling (FDM) were tested for their shape memory properties. Paper shows the relationship between the thermal and electrical conductivities of the filament and its shape recovery performance. The addition of SiC and graphite fillers accelerates the shape memory performance of PLA composites. Electrical conductivity of the filaments was characterized with I-V curves. Thermal conductivity measurements were performed, based on the ASTM D5470, on both FDM filaments and parts made with pure PLA and PLA composites. The results indicated that thermal conductivity increases with increasing SiC filler content. The conductivity increases correlate well with the reduction in the time to induce the shape recovery transition. This correlation enables control of shape transition timings in a part through the design of material composition.

Commentary by Dr. Valentin Fuster
2017;():V014T11A003. doi:10.1115/IMECE2017-71561.

Rapid prototyping has led to strides in improved mechanical part design flexibility and manufacturing time. Along with these advances, however, is the extremely high costs associated with additively manufacturing components that can limit a comprehensive understanding of the mechanical performance of these materials. This can be circumvented through the use of constitutive models which can both support experimental findings in addition to providing approximations of expected material behavior. The present study has demonstrated the influence of build orientation on as-built direct metal laser sintered (DMLS) stainless steel (SS) GP1/17-4PH, manufactured along varying orientations in the xy build plane, through strain-controlled tension and completely reversed low cycle fatigue experiments. Experimental findings from monotonic tension testing are used to model failure surfaces, which can be used to approximate failure regions for DMLS SS GP1 manufactured along varying build orientations within the horizontal xy build plane. Further, a Chaboche model is used to simulate the cyclic response of this material based upon experimental findings through low cycle fatigue testing. Conclusive findings from these models are used to assess the vital role that build orientation plays in affecting the mechanical performance of additively manufactured materials.

Commentary by Dr. Valentin Fuster

Materials: Genetics to Structures: Fracture and Damage: Nano- to Macro-Scale

2017;():V014T11A004. doi:10.1115/IMECE2017-70585.

Numerical simulations were conducted to compare ballistic performance and penetration mechanism of copper (Cu) with four representative grain sizes. Ballistic limit velocities for coarse-grained (CG) copper (grain size ≈ 90 μm), regular copper (grain size ≈ 30 μm), fine-grained (FG) copper (grain size ≈ 890 nm), and ultrafine-grained (UG) copper (grain size ≈ 200 nm) were determined for the first time through the simulations. It was found that the copper with reduced grain size would offer higher strength and better ductility, and therefore renders improved ballistic performance then the CG and regular copper. High speed impact and penetration behavior of the FG and UG copper was also compared with the CG coppers strengthened by nanotwinned (NT) regions. The comparison results showed the impact and penetration resistance of UG copper is comparable to the CG copper strengthened by NT regions with the minimum twin spacing. Therefore, besides the NT regions-strengthened copper, the single phase copper with nanoscale grain size could also be a strong candidate material for better ballistic protection. A computational modeling and simulation framework was proposed for this study, in which Johnson-Cook (JC) constitutive material model is used to predict the plastic deformation of Cu and Ni; JC damage model is to capture the penetration and fragmentation behavior of Cu; Bao-Wierzbicki (B-W) failure criterion defines the material’s failure mechanisms; and temperature increase during this adiabatic penetration process is given by the Taylor-Quinney method.

Topics: Copper , Grain size
Commentary by Dr. Valentin Fuster
2017;():V014T11A005. doi:10.1115/IMECE2017-71335.

The fiber reinforced polymers are candidate materials for critical applications in view of the high strength, stiffness characteristics; however, they are highly anisotropic and have complex failure mechanisms. Thermo-mechanical response characterization is one of the means of identifying damage progression in these materials.

In this study, tensile tests were conducted on the hybrid composite laminates and Infrared thermographs were used to capture the thermal response of the specimen for the entire range of loading till failure. The tests were conducted on natural fiber composite specimens and hybrid (natural + synthetic fiber) composite specimens. The natural fibers used were in the form of uni-directionally stitched mats of Sunhemp, Kenaf and Flax fiber. The synthetic fibers used were bi-directionally woven Carbon fiber mat and Glass fiber mat. All the laminates were prepared using the hand lay-up technique. Four different configurations of the laminates were prepared. The natural fiber composite laminate comprised of Sunhemp fiber mat in a polyester resin system. The Sunhemp fiber mat was also used with woven Glass fiber mat on one side to prepare an unsymmetrical hybrid laminate. The Kenaf fiber mat was placed between layers of woven Glass fiber mats whereas the flax fiber mat was placed between the woven carbon fiber mats; Epoxy LY 556 and hardener Araldite® was used as the matrix. The finished laminate thickness was 2.1 mm and dog-bone tensile specimens were extracted using a CNC router. Some of the specimens were impacted at low velocities from two different heights to study the change in thermo-mechanical response, post-impact, during tensile test. Temperature response as a function of applied stress, failure strain and work done suggests that there is a correlation between the fracture events that take place during tensile test with the temperature response. In cases where there was a ply-drop failure, the rate of temperature change could identify the failure events, even though the resultant peak temperature was less. When the specimen failed by a single mode of failure (delamination/fiber failure), the temperature rise was found to be proportional to the input work done during tensile testing.

Commentary by Dr. Valentin Fuster
2017;():V014T11A006. doi:10.1115/IMECE2017-72654.

This paper presents an investigation on the mechanical response of the Nomex honeycomb core subjected to flatwise compressive loading. Thin plate elastic in-plane compressive buckling theory is used to analyze the Nomex honeycomb core cell wall. A mesoscopic finite element (FE) model of honeycomb sandwich structure with the Nomex honeycomb cell walls is established by employing ABAQUS/Explicit shell elements. The compressive strength and compressive stiffness of Nomex honeycomb core with different heights and thickness of cell walls, i.e. double cell walls and single cell walls, are analyzed numerically using the FE model. Flatwise compressive tests are also carried out on bare honeycomb cores to validate the numerical method. The results suggest that the compressive strength and compression stiffness are related to the geometric dimensions of the honeycomb core. The Nomex honeycomb core with a height of 6 mm has a higher strength than that of 8 mm. In addition, the honeycomb core with lower height possesses stronger anti-instability ability, including the compressive strength and stiffness. The proposed mesoscopic model can effectively simulate the crushing process of Nomex honeycomb core and accurately predict the strength and stiffness of honeycomb sandwich panels. Our work is instructive to the practical applications in engineering.

Commentary by Dr. Valentin Fuster

Materials: Genetics to Structures: Manufacturing and Mechanics of Multifunctional Materials and Structures

2017;():V014T11A007. doi:10.1115/IMECE2017-71455.

Thin-walled metal tubes have been widely used as energy absorbers to mitigate adverse effects of impact and protect structures and facilities. However, once the initial buckling stress of the tube is reached, the post-buckling plateau of the tube has a much reduced average stress which determines the energy absorption efficiency of the empty tube. As a result, the real energy absorption efficiency of the thin-walled tube is much lower than the theoretical limit which is proportional to the value of initial buckling stress. We hypothesize that by filling thin-walled tubes with the novel liquid nanofoam (LN), (i) the energy absorption efficiency of the hybrid structure can reach the theoretical limit, and (ii) the main working mechanism is the effect of solid-liquid interaction on tube buckling.

To test these hypotheses, we have characterized the energy absorption efficiency of LN filled steel tubes by using quasi-static compression tests and dynamic impacts. The quasi-static behavior of LN filled tubes is characterized by an Instron 5982 universal tester. Results show that the gravimetric and volumetric energy absorption efficiencies of LN filled steel tubes are 20% and 220% higher than the values of empty tubes, respectively. This is due to the changed buckling mode and the promoted post-buckling stress of the hybrid structure by the highly compressible LN. The dynamic behavior of LN filled tubes is characterized by a dynamic impact test (∼3 m/s) with a lab-customized drop tower apparatus. It is found that both the gravimetric and volumetric energy absorption efficiencies of LN filled tubes are further increased by 16%. The strain rate dependent behavior of LN filled tubes must be attributed to the solid-liquid interaction between the LN and the steel tube wall, which is further verified by comparing the mechanical behaviors of LN filled tubes with solid foams filled tubes.

Our experimental results have demonstrated that the energy absorption efficiency of thin-walled tubes are significantly improved by the LN filler especially at higher strain rates. This hybrid structure may have a potential for future use in the design of light-weight and small scale cellular structures for vehicle safety and crashworthiness.

Commentary by Dr. Valentin Fuster
2017;():V014T11A008. doi:10.1115/IMECE2017-71648.

Metal matrix composites (MMCs) offer superior mechanical and thermal properties, but the poor machinability of these composites hinders their wide application [1,2]. The machinability of the MMCs are found to be largely dependent on the particle size and volume fraction of the reinforcements used. Experimental investigation on process modeling of MMCs by milling is undertaken. In this study, peripheral milling of functionally gradient concentration of SiC in aluminum matrix using carbide tools is discussed. The process conditions were varied namely, the feed was varied from 0.1 mm/rev to 0.3 mm/rev and the speed from 1000 to 5000 rpm with a constant depth of cut of 1.27mm. The variation of cutting force, surface roughness and cut surface morphology with varying SiC particle distribution, feed and speed are reported. The interaction of the cutting edge with hard SiC particles in Al matrix was also studied using the scanning electron microscopy (SEM). The cutting force and surface roughness were found to increase with increasing volume fraction of SiC particles. Preliminary observation showed that the SiC particles were either removed from the matrix by debonding due to mismatch of thermal coefficients or were fractured by the action of the cutting edge or were pushed into the aluminum matrix.

Commentary by Dr. Valentin Fuster

Materials: Genetics to Structures: Materials and 3D Printing for Biology and Medicine

2017;():V014T11A009. doi:10.1115/IMECE2017-70970.

Objective. The purpose of this study was to characterize and to evaluate the effect of thermal treatment on properties and bioactivity of experimental dental cement.

Methods. Specimens of the dental cement (pellets 13 mm in diameter × 3 mm thick) were prepared by cold pressing of micronized powder of set Alborg White Portland cement. The thermo-gravimetric analysis and differential scanning calorimetry (TGA/DSC) were used to analyze the phase composition and determine the transition temperatures for sintering process. The effect of heat rate and dwell time on density, crystal morphologies, crystalline phases and elemental composition of cement was evaluated by scanning electron microscope (SEM), X-ray diffraction (XRD), X-ray fluorescence (XRF) and micro-Raman spectroscopy.

The bioactivity of set and heat-treated cements was evaluated by ability produce the hydroxyapatite (HA) layer on a surface of specimen immersed in a simulated body fluid (Dulbecco’s Phosphate-Buffered Saline (DPBS). The formation of hydroxyapatite was confirmed by SEM, X-ray energy dispersive spectroscopy (EDS), XRD and and micro-Raman spectroscopy. The amount of produced HA was measured by weight method after 1, 3, 7, and 14 days of immersion.

Results. The set of samples were sintered from experimental dental cement at various heating rate and dwell time. The highest density was obtained at slower heating rate and longer dwell time. The heat treatment changes the hydration phases without changing elemental composition. The heat treatment significantly improves biological performance of dental cement. The heat-treated cement produces 10 times more HA with immersion into simulated body fluid.

Commentary by Dr. Valentin Fuster
2017;():V014T11A010. doi:10.1115/IMECE2017-72205.

Targeted drug delivery has a great importance in cancer treatment and is in interest of many scientists worldwide. Targeted drug delivery renders local treatment of cancerous cells possible without affecting healthy cells. Hydrogels are promising materials to be used in targeted drug delivery systems due to their biocompatible nature and injectable behaviors where they can be used to load drugs. However, considering that not all the drugs are water soluble, entrapment of some drugs into hydrogels is not practical in terms of poor drug solubility and burst drug release because of this. At this point, an oil phase can be considered as a drug carrying agent, and entrapment of this oil phase into hydrogel would make it possible for in-situ injection of dissolved drug in oil phase.

Oil in water (O/W)-type nanoemulsions were prepared using black seed oil, which is known to cause apoptosis via p-53 dependent mechanism, water and Triton X-100, Span-80 surfactant combinations. Three different oil percentage and three different surfactant percentage were tested, and stability behaviors of nanoemulsions were investigated and compared. Dynamic light scattering analysis and zeta potential measurements were conducted for determination of particles sizes and surface charges of the nanoemulsions. The most stable nanoemulsion along with having smallest diameter and lowest polydispersity index (PDI) was used for further studies. Results indicated that using both hydrophilic and hydrophobic surfactants together increased the stability of nanoemulsions compared to those using either of them.

Topics: Stability , Water
Commentary by Dr. Valentin Fuster

Materials: Genetics to Structures: Materials Processing and Characterization

2017;():V014T11A011. doi:10.1115/IMECE2017-70169.

The GMAW process using two wires is an alternative to a coating process when high productivity is desired. The potential variants emerging from this process are GMAW cold wire and GMAW double wire. One of the greatest difficulties is the setting of its parameters, which duplication compared to conventional GMAW and also act in a dependent manner. A greater understanding of the technology applied to coatings on turbines in various positions is critical to master the process and its variables for enhancing industrial applications. This study involves an experimental evaluation to verify the influence of some variables on the profile of cord and wear resistance. This paper proposes making deposits with weld metal AWS 308LSi stainless steel and alloys of cobalt (Stellite 6 and 21) plates in carbon steel SAE 1020 in the flat positions. The wear characterization in the lining is used to determine the hardness and surface topography. It is concluded that cobalt alloys have superior resistance to erosive damage, with emphasis on Stellite 21 with respect to erosion and Stellite 6 with respect to cavitation. Mixtures of austenitic stainless steel and cobalt alloys have intermediate wear values. Therefore, it is essential to study welding processes with multiple wires, as proposed in this paper, to determine the optimal combination of alloys for resistance to cavitation-erosion phenomena.

Commentary by Dr. Valentin Fuster
2017;():V014T11A012. doi:10.1115/IMECE2017-70628.

Liquid crystalline polymers (LCP’s) make up a class of high performance materials, which derive favorable mechanical, chemical, and electrical characteristics from their long-range molecular order. The unique LCP microstructure gives rise to anisotropic bulk behavior and an understanding of the driving forces behind this morphology is essential to the design of manufacturing processes for isotropic material production. In this investigation, the crystalline orientation in injection molded LCP plaque samples was measured using 2D wide-angle x-ray scattering (WAXS). The direction of preferred alignment was observed from the WAXS scattering patterns and the degree of orientation in the material was quantified using an order parameter and an anisotropy factor. In addition, the dielectric constant was measured with respect to the mold direction (MD) and transverse direction (TD). To investigate the effects of processing on hierarchal structure in the material, and the resulting macroscopic properties, plaques of two different thicknesses were analyzed, both as-injection molded and with the skin layer mechanically removed. It is shown that preferred orientation along the shear direction in the LCP samples corresponds to dielectric anisotropy, and increasing sample thickness, or conversely, mechanically removing the shear aligned layer, results in a more isotropic dielectric response.

Commentary by Dr. Valentin Fuster
2017;():V014T11A013. doi:10.1115/IMECE2017-70659.

Besides pad failure due to thermal damage, brake pads can also experience mechanical damage when they are exposed to a corrosive environment. A typical solid surface like a brake pad has a complex structure and complex properties depending on the nature of the solids, the method of surface preparation, and the interaction between the surface and the environment. The surface roughness of a novel friction linings prepared using varying palm kernel shell (PKS) powder particle sizes (0.300 mm, 0.425 mm and 0.850 mm) as reinforcements were investigated. The investigation was conducted via a profilometer dotted with a diamond stylus at a speed of 0.2 m/s. The determined surface roughness parameters values were in ascending order with S0.300 having the least values (Ra = 6.13 μm, Rz = 24.04 μm and Rmax = 37.3 μm) and S0.850 having the highest values (Ra = 9.87 μm, Rz = 37.28 μm and Rmax = 53.8 μm). This was an indication that the roughness characteristics of the reinforced composite were associated to the presence of pulverised PKS particles. It was further shown by scanning electron microscope images that pulverised PKS grain sizes by nature have rough surfaces and this could have contributed to the overall roughness behaviour of the reinforced composite since PKS was the only ingredient with grain size variation in the experiment.

Commentary by Dr. Valentin Fuster
2017;():V014T11A014. doi:10.1115/IMECE2017-70721.

Methods for scalable surface texturing continues to receive significant attention due to the importance of micro-textured surfaces toward improving friction, wear and lubrication ability of mechanical devices. Controlled textures on surfaces act as fluid reservoirs and receptacles for debris and wear particles, reducing friction and wear of mating components. There are numerous fabrication techniques that can be used to create micro-sized depressions on surfaces, but each has limitations in terms of control and scalability. In the present study, modulation-assisted machining (MAM) is demonstrated as a viable approach to produce such textures, offering a potentially cost-effective approach for scalable production of these features on component surfaces.

In this work, the wear behavior of several textured surfaces created by MAM was studied using a ball-on-flat reciprocating tribometer. Textured and untextured alloy 360 brass disks were mated with stainless steel AISI 440C balls under lubricated conditions and variable sliding distance. The textured surfaces exhibited noticeably reduced wear under the longer sliding distances and the tribological performance of the surfaces depended on the size of the micro-dimples. Wear mechanisms are elucidated from the optical microscopy, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) observations and the implications for using such surfaces in practice are briefly discussed.

Topics: Wear , Machining
Commentary by Dr. Valentin Fuster
2017;():V014T11A015. doi:10.1115/IMECE2017-70784.

This paper proposes to identify the strength characteristics for a particular woven hemp fabric from a collection of data representing the strengths derived from bursting strength testing based on moisture content. The Ball Bursting Strength Test, D3787 and ASTM 6797, define the size of puncture tool and the speed of force application for the bursting test procedure. The bursting strength test is a method of defining the strength of a woven fabric in two directions simultaneously given a single force perpendicular to the fabric surface. Plotting the resultant bursting force against the apparent modulus of elasticity for each sample, sets the variance in strength for the elastic range against the variance for the elastic range. The amount of variance of any particular data point from an overall group mean will help identify its association with a group of data points all belonging to a common family of test samples. Recognizing that a particular data point is likely to belong to a group of data points and less likely to belong to another group of data points given the parameters of variance and mean for any group of points, is the function of the Gaussian Mixture Model with Expectation Maximization (GMMEM).

Commentary by Dr. Valentin Fuster
2017;():V014T11A016. doi:10.1115/IMECE2017-71090.

Many manufacturers are looking towards electrical treatments as methods for reducing residual stresses in formed metals. Although many people have investigated the effects electricity has on residual stresses and plasticity, there has not been research investigating the effects it has as a post-treatment on strain hardening. Therefore, the goal of this research is to show the permanent changes in tensile properties that electrical treatments have on strain hardened metals, specifically Aluminum 2024. For this initial investigation, only one pulse duration and current density was used to categorize any changes in the metals due to applying electric current. This testing shows the difference between post-deformation heat treatments and post-deformation electrical treatments. Tensile properties of Aluminum 2024 were used to gauge the changes caused by the treatments. The heat treatment had the expected effect of lower the strength of the material and regrowing the grains while the electrical treatment did not seem to drastically change the structure of the grains, but still lowered the strength of the material. Microstructure investigations also showed that the material does in fact show slight changes in material properties, but no drastic changes in microstructure. These images also show that the regrowth from the heat treatment is clearly the reason for the decrease in strength.

Commentary by Dr. Valentin Fuster
2017;():V014T11A017. doi:10.1115/IMECE2017-71177.

Polymer composites have a characteristic, composition specific visco-elastic property which influences the damage progression during fatigue cycling. While some researchers have studied the time dependent constitutive response of polymer composites during the first cycle of fatigue loading, very few have experimentally investigated the dependence of visco-elastic response of built-up polymer composite materials at various stages of fatigue cycling [1]. Our earlier studies on fatigue response of polymer composites focused primarily on the stiffness degradation as a function of applied cycles of loading, which represents the gross response of the material [2]. While doing such an experiment, complimentary experimental techniques to measure the temperature evolution was attempted through the use of infrared thermal imaging technique, which gave some insight into the change in temperature response as a function of fatigue cycling. However, there was no systematic measurement of creep and stress relaxation response of the composite material as a function of induced fatigue damage.

The present paper describes the results of creep and stress-relaxation obtained during uni-axial fatigue loading of a hybrid polymer composite material. For this purpose, a woven carbon fiber mat was chosen as the synthetic fiber and Flax fiber in the unidirectional form was chosen as the natural fiber that is laid between the two layers of woven carbon fiber mat. Epoxy LY 556 and hardener Araldite® was used for building up of composite laminate by hand-lay-up technique. Dog-bone shaped tensile specimens with a gage width of 13 mm and gage length of 57 mm were extracted from the 250 × 250 mm sq. plate laminate of 2.1 mm thickness using a numerical controlled milling machine. The specimens were tested at 35% of their median tensile strengths under fatigue at a positive stress ratio (Pmin/Pmax) of 0.1 in tension-tension loading. Prior to start of fatigue loading, the specimens were held in load control and the strain in the gage length was measured for understanding the creep response over 2500 seconds. For stress-relaxation characterization, the specimens were held in extensometer control over a period of 2500 sec. The creep and stress relaxation tests were carried out after periodic intervals of fatigue cycling.

It was observed that in the case of un-impacted specimens, the creep rate is consistent with the stiffness variation, which in turn, is dependent on the number of fatigue cycles - till it showed signs of de-lamination. Thereafter it was governed by the woven synthetic fiber response. Similarly, the stress relaxation response was found to decrease with increasing fatigue cycles. In case of impacted specimens, the local deformation had a prominent role in terms of creep and stress relaxation response.

Commentary by Dr. Valentin Fuster
2017;():V014T11A018. doi:10.1115/IMECE2017-71370.

Galvanic sludge is a solid waste produced by the surface treatment industry, classified as hazardous because of their high concentration of heavy metals, which in its final destination is disposed in waste disposal facilities, with economic costs to the holders. Through hydrometallurgical processing, it is possible to extract valuable metals, with low costs involved, while the hazardous level of the residue is reduced.

In the present work, the heap leaching method was studied as a solution to the treatment of these residues, which in order to consist in a valuable option, processing and operation costs must be kept as low as possible. For the experimental testing, a closed loop lixiviation column for hydrometallurgical treatment of galvanic sludge with possibility of continuous flow of the leachate (and static process as well) was constructed, simulating the heap leaching process. The galvanic waste in study, delivered by a local surface treatment company, was both chemically and physically characterized, proving to be rich in valuable metals like Nickel, Chromium and Copper.

The waste material was characterized both for physical parameters (grain size) and chemical composition.

The lixiviation trials, with a maximum duration of 1 week, were conducted. The influence upon the extraction rate of metals such as Nickel, Chromium and Copper, of parameters such as the concentration of the leaching agent (sulfuric acid) and time were tested. In order to quantify the leachate circulation effect, a static trial was conducted as well. Extraction rates of 35.5 % of Nickel, 14% of Copper and 13.6 % of Chromium were obtained after 6 hours in a dynamic trial, with 100 g/L sulfuric acid solution concentration. The acid consumption rate was correlated with the metal extraction.

Finally, the results were compared with others obtained in previous galvanic sludge agitation lixiviation and laterites heap leaching works.

Commentary by Dr. Valentin Fuster
2017;():V014T11A019. doi:10.1115/IMECE2017-71529.

High temperature corrosion is a grave problem in incinerators, boilers, turbines and IC engines. To prevent hot corrosion, alloying of metals is usually done. But it does not conserve mechanical properties like creep, toughness, ductility etc. Coating is a generic way to enhance the materials life at elevated temperature in the presence of salts. Sol-gel method of coating is easy and cheap as compared to thermal spray coatings. In the present work, Cerium substituted Silicon-Zirconium coating is prepared via Sol-Gel route. It is deposited on Chromium based super alloy SS-304. Sol-gel dip coating method is used for coating the materials. Cyclic oxidation tests are performed at 900°C in the presence of Na2SO4 salt solution on coated and bare samples. The weight gain analysis shows that coated samples have shown better corrosion resistance than bare specimen cyclic oxidation in simulated environment. SEM, EDS and X-ray mapping techniques are also confirmed that organic precursors of Silicon and Zirconium useful in creating uniform coating. However, coating showed cracks after calcinations which may be due to higher rate of drying. But cracks become self-healed when specimen was subjected to simulated environment at 900°C due to grain growth of Zirconium particles. X-ray mapping showed that protective layer of cerium and Zirconium present at surface of SS-304 and coating was successful in providing resistance to substrate metal from penetration of salts.

Commentary by Dr. Valentin Fuster
2017;():V014T11A020. doi:10.1115/IMECE2017-71532.

A common failure mode of electronic PCB’s is the appearance of cold solder joints between the component and PCB, during product life. This phenomenon is related to solder joint fatigue and is attributed mainly to the mismatch of the coefficients of thermal expansion (CTE) of component-solder-PCB assembly. Although some experiments show that newer lead-free tin-silver-copper (Sn-Ag-Cu, or SAC) solders perform better than the older SnPb ones, with today’s solder joint thickness decreasing and increasing working temperatures, among others, the stresses and strains due to temperature changes are growing, leading to limited fatigue life of the products. As fatigue life decreases with increasing plastic strain, creep occurrence should have significant impact, especially during thermal cycles. In order to improve mechanical properties, but also as an attempt to reduce maximum reflow cycle temperatures due to component damage and production costs, various SAC solder alloying additives are being considered to use in industrial production facilities. Solder paste producers are proposing new products based on new solder paste formulations, but the real life effects on thermo-mechanical performance aren’t well known at the moment. In this paper a dynamic mechanical analyser (DMA) is used to study the influence of Bismuth (Bi) addition, up to 5 wt %, on SAC405 solder paste, in terms of creep behaviour. Creep tests were made on three-point-bending configuration, isothermally at 30 °C, 50 °C and 75 °C, and three different stresses of 3, 5 and 9 MPa. The results shown not only a significant Bi concentration influence on creep behaviour but also a noticeable temperature dependence.

Topics: Creep , Solders
Commentary by Dr. Valentin Fuster
2017;():V014T11A021. doi:10.1115/IMECE2017-71828.

All manufacturing methods produce components which have some degree of inhomogeneous properties. Part properties may vary with location in most fabrication methods including additive manufacturing, casting, forging, welding, and surface modifications. Standard tensile test specimens cannot provide a good map of the properties of the material, except for only the largest of components or simplest of geometries. For example, simple curved shapes, such as pipes cannot be reliably evaluated by straight tensile specimens unless the pipe diameter is large enough to have a sufficiently low curvature from which flat specimens can be machined.

This paper will look at part property variations in various components made by different fabrication methods, which include selective laser melting, press and sinter powder metallurgy, rolling and casting. Subsize tensile specimens developed at the Missouri University of Science and Technology have been used to map out material properties with location. This method of mapping out properties provides new information which could be valuable to quality control, process control, and design of components.

Commentary by Dr. Valentin Fuster
2017;():V014T11A022. doi:10.1115/IMECE2017-71886.

Zirconia and Silicon-carbide based castable composites are both known to be reliable, high-temperature refractory materials, capable of withstanding damage caused by thermal shock. There exists a growing body of literature regarding micro-scale as well as macro-scale properties of each aforementioned type. In the present work, we have investigated these refractory castables using different volume fractions of ZrO2 and SiC particles and have made a comparison between their thermal shock responses. Equivalent homogeneous material properties including elastic modulus, crushing strength and modulus of rupture (MOR) are determined experimentally, and thermal shock experiments at 900°C are conducted to determine the effect of the compositions on the propensity of these castables to survive thermal shock. The experimental findings were compared to predictions made by thermal shock indices and the two were in good agreements. Applying thermal shock cycle in all cases showed a drop in strength and elastic modulus of the material.

Commentary by Dr. Valentin Fuster
2017;():V014T11A023. doi:10.1115/IMECE2017-72268.

Different material attributes such as mix volumetrics, aggregate gradations, and binder characteristics are the factors affecting viscoelastic material functions of asphalt concrete. In this study, the effects of aggregate gradation on the complex modulus function of asphalt concrete are determined. The two distinct properties of the aggregate blend considered in this study are the fineness modulus and the uniformity coefficient. A total of 54, plant produced, asphalt concrete mixtures with asphalt binders having various performance grades and sources were collected from the manufacturing plants. The asphalt-aggregate mixtures were then compacted, cored, and sawed to cylindrical specimens. Three cylindrical specimens from each of the asphalt-aggregate mixtures were prepared and tested in the laboratory for complex or dynamic modulus. After that, average mastercurves of complex modulus and phase angle were generated by applying time-temperature superposition principle. Study showed that the complex modulus function of asphalt concrete is significantly related to the fineness modulus and uniformity coefficient of the aggregate blends used in the asphalt-aggregate mixture.

Commentary by Dr. Valentin Fuster
2017;():V014T11A024. doi:10.1115/IMECE2017-72562.

Aluminium alloys used in automobile applications are generally heat treated to obtain a desired combination of strength and ductility. The knowledge in treatment temperature as well as the time of this process is essential for optimum results. In this paper A356 alloy is subjected to different heat treatment conditions and examined its effects on the mechanical properties and corrosion behaviour. The solutionizing temperature and time were 540°C and 1 hour respectively, followed by 24 hours of natural aging and the artificial aging temperature and time were 180°C and 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6 hours respectively. The standard T6 heat treatment process performed were used as reference in-order to compare the effect of artificial ageing. The solutionizing temperature for 1 hour and artificial ageing time of 4.5 hours produced peak compressive strength when compared to other aging times.

Commentary by Dr. Valentin Fuster

Materials: Genetics to Structures: Mechanical Metamaterials

2017;():V014T11A025. doi:10.1115/IMECE2017-70904.

Mechanical metamaterials are man-made materials in which the mechanical properties are mainly defined by their structures instead of the properties of each component. Periodic cellular structures consisting of honeycomb, tetrahedral, 3D Kagome and pyramidal truss arrangement of webs or struts have recently attracted a lot of attention since they have a broad range of applications including structural components, energy absorption, heat exchangers, catalyst support, filters and biomaterials. In addition, lattice structures such as the octahedral are being investigated since they are structurally more efficient than foams of a similar density made from the same material, and the ease with which these structures can now be produced using 3D printing and additive manufacturing.

This research investigates the mechanical behavior and anisotropy in octahedral lattice structures of two different relative densities fabricated out of Acrylonitrile butadiene styrene (ABS) using Stratasys FDM 360mc and Dimension sst 1200es 3D printers. The machines were used to print octahedral lattice structured parts with struts 1.00 mm in diameter followed by parts with struts 2.6 mm in diameter and tested in compression in three mutually perpendicular directions. The compressive stress-strain behavior of the lattice structures observed is typical of cellular structures which include a region of nominally elastic response, yielding, and plastic strain hardening to a peak in strength, followed by a drop in flow stress. It was found that not only is the stiffness and strength of the as fabricated parts anisotropic but they, in addition to failure, are also a function of the relative density/strut diameter of the structure.

Topics: Anisotropy , Failure
Commentary by Dr. Valentin Fuster

Materials: Genetics to Structures: Multifunctional Composite Materials and Structures

2017;():V014T11A026. doi:10.1115/IMECE2017-71880.

Due to depleting natural resources, it is necessary to develop eco-composite materials that are fabricated from sustainable and inexpensive materials such as recycled paper or cellulose-based materials. Such materials are required to meet the mechanical performance at par with traditional materials. The main aim of this study was to investigate the mechanical performance of a composite material fabricated from paper pulp and polyvinyl acetate (wood glue). It is expected that a high strength composite material may be achieved by varying the amount of paper-pulp fiber fraction from 7.5%, 10%, 20%, 30%, 40%, 50% to 60% weight. A tensile test was conducted and it was found that an increase in fiber content on the fabricated composite resulted in an increase in ultimate tensile strength and a decrease in corresponding strain. Furthermore, the material becomes more brittle at higher fiber content and conversely, more ductile at lower fiber content. The ultimate tensile strength was found to be 7.69 MPa at 60% w.t fiber and the minimum tensile strength was 0.12 MPa at 0% w.t fiber. There were no signs of fiber content limit observed in the obtained results. It was concluded that a composite of moderate strength was produced and future work is required in order to fully understand how the composite behaves at different loading conditions. However, an optimum fiber content limit will have to be determined.

Commentary by Dr. Valentin Fuster
2017;():V014T11A027. doi:10.1115/IMECE2017-72481.

This study has been made to limit the sliding wear by employing advanced protective nano coatings by using DC magnetron sputtering Physical Vapour Deposition technique. Three advanced nano coatings viz. Diamond-Like Carbon (DLC), composite AlCrN coating and AlCrN/TiAlN multilayered coatings were selected for present work due to their enviable wear resistant characteristics. Coatings were deposited on AISI-D2 die steel by traditional DC magnetron sputtering physical vapour deposition technique. The as deposited coatings were characterized with surface roughness, microhardness, porosity and microstructure. The X-Ray Diffraction (XRD) and field mission scanning electron microscope (FESEM with EDAX) techniques have been used to describe various phases established after coating deposited on the surface of the substrate. Subsequently, sliding wear and friction tests were conducted in accordance with ASTM standard G99-03, under scrutiny variation of load and time and at constant sliding speed. Cumulative wear volume loss and coefficient of friction were formulated for coated as well as uncoated/tempered specimen at a constant speed of 1 m/s and varying load of 25N and 50N. The results from experimentation were analysed with SEM micrographs and Energy dispersive spectrum to analyse the adaptability of coating for base materials, wear behaviour and friction behaviour of coated and uncoated/tempered substrates. The results have shown adaptability of advance nano-coatings for AISI D2 die steel. The generation of oxide layer during wear process provides wear resistance to the AlCrN-based coatings. No thermal instability has been observed in nano-coatings at low temperature generated while experimentation and that is under working range of cold forming processes. It is observed that there is relevant decrease in frictional force by the application of DLC coatings while AlCrN/TiAlN has provided much better wear resistance.

Topics: Steel , Stress
Commentary by Dr. Valentin Fuster

Materials: Genetics to Structures: Multiphysics Behavior of Lithium-Ion Battery: Modeling, Simulation and Experiment

2017;():V014T11A028. doi:10.1115/IMECE2017-71858.

Based on previous numerical models of spirally-wounded lithium-ion cells and the coordinate transformation method, a new method to carry out real-time calculation and simulation to predict the temperature distribution within the cell is developed. Based on the coupling of heat equation and a pseudo two dimensional (P2D) physics-based electrochemical model, samples of input combinations covering the input space are collected as training data. Computer experiments to predict current source density and thus heat generation rate in the cell with Gaussian process are done to exam the validity of the method.

Topics: Computers , Lithium
Commentary by Dr. Valentin Fuster
2017;():V014T11A029. doi:10.1115/IMECE2017-72144.

To understand the mechanical interaction between pouch cells in a battery module and improve the crash safety designs for the power battery system of electrical vehicles, a type of simplified battery module consisting of three pouch cells is designed and tested under impact loading with a drop tower. A finite element model is developed to analyze the response of battery module, and a series of calibration and verification tests are conducted to acquire the homogenized material properties of the single cell. Various loading conditions and factors concerning the safety design of batteries under crash scenarios, e.g. impact speed, drop mass and gaps between cells, are analyzed and discussed in terms of the influence on the mechanical, electrical and thermal responses.

Topics: Lithium , Batteries
Commentary by Dr. Valentin Fuster

Materials: Genetics to Structures: Nanoengineered, Hierarchical, and Multi-Scale Materials and Structures

2017;():V014T11A030. doi:10.1115/IMECE2017-72713.

Carbon Nanotube (CNT) fibers are 3D-woven hierarchical assemblies of CNTs which show excellent mechanical and electrical properties. There is a tremendous loss of mechanical performance in the scale transition from individual CNT to fibers, over which we have limited understanding. Our knowledge of load transfer across different length scales is scarce and inconclusive. Here, the objective is to explore the load transfer mechanism (LTM) of CNT fibers, by identifying the contribution of defects on mechanical performance of fibers at various length scales. A micromechanical-based constitutive model is developed to describe bending-tensile properties of strands as an assembly of twisted yarns. The model associates the strand response to two states of deformation referred to as stick and slip states. Several inelastic features were considered in calculation of the response of strands, such as local jamming, evolution of the void area between yarns, and friction. The model is validated against different sets of experiments.

Commentary by Dr. Valentin Fuster

Materials: Genetics to Structures: Nanomaterials for Energy

2017;():V014T11A031. doi:10.1115/IMECE2017-70993.

The recent growth in portable electronics has sparked a demand for alternative energy sources. Energy harvesters that utilize piezoelectric materials are promising in capturing the mechanical energy from body movement to power portable electronics. This study investigated the characteristics of PVDF-HFP nanofibers created from traditional electrospinning and a novel technique called wet-stretching electrospinning. The solution was initially processed using the traditional method, flat-plate electrospinning, which resulted in a fiber network with random orientations. When performing electrical testing the fibers produced minimal voltage. The solution was then processed utilizing a novel wet-stretching electrospinning technique that allowed for fiber alignment and dynamic stretch ratios. Fibers that underwent this method produced higher voltages than fibers from the traditional electrospinning method. It was observed that fibers processed using the wet-stretching technique with different draw ratios (DR) such as 1 (DR 1) and 2.5 (DR 2.5) showed enhanced piezoelectric properties. This research suggests that the wet-stretched PVDF-HFP nanofibers are better suited for piezoelectric applications than traditionally electrospun nanofibers.

Topics: Nanofibers
Commentary by Dr. Valentin Fuster
2017;():V014T11A032. doi:10.1115/IMECE2017-71495.

Renewable energy sources demands sustainable energy storage technologies through the incorporation of low-cost and environment-friendly materials. In this regard, cellulose nanocrystals (CN), which are needle-shaped nanostructure derived from cellulose-rich resources, are extracted by sulfuric acid hydrolysis of biomass and used as both template and binder for the construction of electrochemical capacitors electrodes. A composite material is synthetized comprising CN and a conjugated electroactive polymer (CEP) to overcome the electrical insulating properties of cellulose as well as to exploit enhanced electrochemical activity by increased electrode surface-area. A one-step in-situ film synthesis protocol is evaluated by performing simultaneous polymerization and film deposition. The effect of proportion of starting components are evaluated through statistical Response Surface Methodology towards optimizing the electrochemical performance. Depending on the mass proportion of the starting components, a conducting network could be created by surface coating of the CEP on the whiskers during polymerization. Electrochemical measurements suggest an increase in specific surface area by at least a factor of two relative to bare CEP as a consequence of the template role of cellulose. Therefore, adjustment of the proposed one-step synthesis parameters allows tuning the material properties to meet specific application requirements regarding electrochemical performance.

Commentary by Dr. Valentin Fuster

Materials: Genetics to Structures: Phase Transformations in Materials Processing and Their Effects on Mechanical Properties

2017;():V014T11A033. doi:10.1115/IMECE2017-71019.

The formation of porosity and bubbles during solidification in manufacturing processes like casting or welding of metals has a negative effect on the mechanical properties of the manufactured components. Numerical simulation of this problem is important since the direct observation of the interaction of bubbles with dendrites is limited by the opacity of metals. Therefore, developing a reliable numerical model is essential to predict the mechanical properties of materials after solidification.

The pseudopotential multiphase model is a popular method for simulating multiphase flow using the lattice Boltzmann method. This model and its variations have been used to simulate a variety of problems successfully. However, the original pseudopotential model has some deficiencies, including large spurious current and restriction to model low density and viscosity ratios. Several schemes have been proposed to improve the pseudopotential multiphase model and overcome the limitations, including using a realistic equation of state, introducing a force with higher order of isotropy, introducing a middle-range repulsion force, and implementing the force similarly to the Exact Difference Method (EDM).

The aim of this article is to investigate these various enhancements available for the pseudopotential multiphase model in order to come up with a reliable scheme to simulate motion and interaction of bubbles during dendritic solidification in binary alloys. The proposed model is validated against published literature.

Commentary by Dr. Valentin Fuster
2017;():V014T11A034. doi:10.1115/IMECE2017-71921.

Using phase field modeling simulation approach we investigate the effect of various parameters on the primary and secondary dendrite arm spacing during directional solidification in a single component system. In previous studies the effect of temperature gradient was assumed to be negligible in the transversal directions with a temperature rate equal to the product of thermal gradient and solidification rate. In our study the temperature field is obtained from energy conservation equation by considering the balance of latent heat released in the regions where solidification occurs and energy dissipation due to directional temperature gradient as boundary condition. In our simulations, we implemented a numerical method that enables the investigation of solidification in larger domains. Specifically, the temperature and the order parameter equations are solved only in the domains close to the solidification front; approach that reduces the computational costs significantly. We investigate the interplay and the effect of thermal gradient, solidification rate, undercooling temperature, and the cooling heat flux on arm spacing. By using a well-established power law relation the primary and secondary arm spacing are calculated for various solidification parameters. We also show that, for large heat fluxes, the secondary arm spacing is almost constant for different undercooling temperatures; behavior that demonstrates the need for correction of the power law relation by including the effect of heat flux.

Commentary by Dr. Valentin Fuster

Materials: Genetics to Structures: Processing Innovations in Lightweight Materials

2017;():V014T11A035. doi:10.1115/IMECE2017-70627.

The micro-alloying effect, mechanical properties, and plastic deformation behavior of extruded Mg-Zr alloy were investigated and characterized as a function of Zr addition, grain size, and texture. The experimental methodology used in this study was design to exploit the hot-extrusion processing parameters (in the terms of extrusion ratios and temperature) and its effect on Mg extruded alloys microstructure, texture, and mechanical properties. Microstructural observations revealed significant grain refinement through a combination of Zr addition and hot-extrusion, producing fine equiaxed grain structure with grain sizes ranging between 1–5 μm. Texture analysis and partial compression testing results showed that the initial texture of the extruded alloy gradually evolved upon compressive loading along the c-axes inducing contraction twinning creating a strong basal texture along the extrusion direction. Full tensile and compression test at room temperature showed that the combination of hot-extrusion and Zr addition can further refine the grains of the Mg alloys microstructure and enhance the texture while simultaneously enhancing the mechanical properties.

Topics: Alloys , Extruding , Zirconium
Commentary by Dr. Valentin Fuster
2017;():V014T11A036. doi:10.1115/IMECE2017-71008.

MgZnCa and MgZnCa-RE (Rare Earth) alloys were developed for biomedical applications. Small wires of the alloys were successfully fabricated from the small rods prepared by hot-extrusion followed by multiple cold-drawing passes with intermittent annealing. It was demonstrated that addition of small amounts of rare earth (RE) elements could effectively enhance the mechanical properties of the wires. The ductility or deformability under twisting test was greatly improved by post annealing at relatively high temperatures.

Topics: Wire , Bone , Biodegradation
Commentary by Dr. Valentin Fuster
2017;():V014T11A037. doi:10.1115/IMECE2017-71987.

Formation of long-period stacking ordered (LPSO) phases can significantly improve mechanical and corrosion properties of Mg-alloys. Typically LPSO phases can be formed by quick solidification of Mg-alloys having at least two alloying elements with atomic radii higher and lower than that of Mg. Stability of LPSO phases greatly depend on amounts and ratio of alloying elements. We report formation of thin film LPSO structures produced by co-sputtering of magnesium with zinc and gadolinium having less than 10% of alloying elements. This method allows controlling the ratio of the elements in composition, deposition temperature and orientation of thin films. Pure Mg, Zn and Gd films and their alloys deposited at temperatures below 200°C have HCP Mg-based crystallographic structure with exclusively basal orientation. LPSO phases and their stacking period were detected by observation of laminar structure patterns in low-angle x-ray reflectometry scans. The study of effects of elemental composition, deposition temperature and post-annealing of room temperature-deposited films on the formation of LPSO phase showed that the co-sputtering method can be very useful and efficient for the screening of new LPSO phases without the considerable expense preparation of bulk alloy preparation.

Topics: Thin films , Alloys
Commentary by Dr. Valentin Fuster
2017;():V014T11A038. doi:10.1115/IMECE2017-72285.

This study focused on understanding the interactions between alloying elements in a magnesium (Mg) matrix and the effect of the alloying elements on corrosion behavior of Mg-alloys. The development of atomic force microscope (AFM) techniques has enabled the evaluation of physical and chemical properties of surfaces at the sub-micron level. Scanning Kelvin probe force microscopy (SKPFM) is particularly useful for studying localized corrosion phenomena of alloys. SKPFM generates a map of the potential distribution across a sample with a resolution of probe tip radius, nowadays ranging from 5 to 30 nm. Furthermore, the open circuit potential of various pure metals in solution is linearly related to the Volta potential value measured in air immediately after exposure to corrosive media. SKPFM is a useful tool to practically assess the nobility of a surface. This technique has been applied to the heterogeneous microstructure of Mg-Zn-Ca-RE (RE = Zr, Nd, Ga) alloys and provided clear evidence regarding the shape, position, compositional inhomogeneities and local practical nobility of intermetallic particles. Correlation between the measured potential distribution and the reactivity of these particles has been shown. Atomic force lithography (AFL, scratching with the hard tip) is a controlled method for local disruption of the protective oxide film that naturally formed on an Mg-surface in air. Combining SKPFM and AFL, the stability of the passive film and the tendency for stabilization of localized corrosion can be monitored. In addition, the lateral imaging capabilities of the AFM provide an approach to study the role of different microstructural features such as grain boundaries and impurities in the process of inducing localized corrosion.

Topics: Alloys , Microscopy , Probes
Commentary by Dr. Valentin Fuster

Materials: Genetics to Structures: Processing, Structure and Property of Polymers and Composites

2017;():V014T11A039. doi:10.1115/IMECE2017-70233.

Ultrahigh molecular weight polyethylene (UHMWPE) fibers have been investigated for years to improve performance with gel spinning process for wide applications in industry. Various spin solvents have been attempted including paraffin oil, decahydronaphthalene (decalin), kerosene etc. However, more work still needs to be done because of environmental issues or long extraction process of the aforementioned solvents. Recently, polybutene was found to be an effective spin solvent for UHMWPE fibers, which is environmentally friendly and widely available on the market. Besides producing high strength fibers, compared to paraffin oil, polybutene can form a gel with UHMWPE showing stronger phase separation behavior at room temperature. Because of this property, more extraction solvents can be saved. It was also demonstrated with experiments that the extraction efficiency is higher than that of the gel fiber formed with paraffin oil. Thus, polybutene has high potential to be used in large-scale production of UHMWPE fibers, which deserves further study.

In this work, polybutene with different molecular weight was used to form spin dopes with UHMWPE. The dope concentration for each type of polybutene was also varied to check the effect of molecular weight and dope concentration on fiber properties. Viscoelastic properties of the spin dopes were obtained with parallel plate rheometry while thermodynamic properties of the dopes were characterized with differential scanning calorimetry (DSC) and thermal gravitational analysis (TGA). With optimized processing conditions, high strength fibers were collected and the crystalline structure was examined with wide angel X-ray diffraction (WAXD). DSC and TGA data also provided support for the effect of molecular weight and concentration of polybutene. It can be found that stronger fibers are obtained with lower concentration spin dopes. The viscosity of the dopes and corresponding spinning conditions are significantly affected by molecular weight of polybutene. Extraction efficiency is affected by both molecular weight and dope concentration. To obtain cost-effective superstrong UHMWPE fibers, an optimized design is needed based on the molecular weight of polybutene and the spin dope concentration.

Commentary by Dr. Valentin Fuster
2017;():V014T11A040. doi:10.1115/IMECE2017-70386.

In order to design the products made from soft materials, it is important to quantify the deformation characteristics of them for the quality and reliability of their design. But the quantification is ordinary difficult because of large deformation due to its softness even if the tensile test which is one of the fundamental technique is easily applied to the quantification for hard materials. Here, usefulness of indentation test is reported for soft materials by extending the Hertzian contact theory. Then the indentation technique based on the contact theory is adopted for quantification in this paper. This theory is commonly used to evaluate elastic materials, but it is found that inelastic behaviors of solid materials like viscosity and fracture can be quantified by the extension of the theory. In this paper, an evaluating equation is formulated and applied to quantify in-elasticity of various materials and it is known that an equation can analyze the variation of soft materials objectively, and the analyzed results has high compatibility to uniaxial test like the fundamental Hertzian contact theory.

Commentary by Dr. Valentin Fuster
2017;():V014T11A041. doi:10.1115/IMECE2017-70412.

Polyetheretherketone is a widely used engineering polymer that is especially suitable for high-temperature applications. Graphene is a two-dimensional form of carbon nanomaterial that has been studied extensively for its mechanical, electrical and thermal properties and its use as a filler in polymer matrices. Compounding graphene into polymers has the potential to improve various properties, even at very low concentrations. In this work, we have examined the incorporation of graphene nanoplatelets (GNP) into PEEK. We have fabricated composites using melt-mixing techniques, as well as by graphene functionalization and in-situ polymerization of the PEEK. In this way, we can compare the performance of the composites by two different processing methods. The GNP-PEEK composites were characterized by DSC, TGA, and SEM. Lap-shear joints using the GNP-PEEK as the adhesive were made and mechanically tested. Results show that the weight fraction of GNP has a major effect on the strength of the joint. In this work, we aim to produce a material that functions as a reusable high-temperature, thermoplastic adhesive, which can be activated by conventional heating methods, or by microwave heating. The GNPs act as microwave absorbers and heat the surrounding PEEK matrix to the point of melting, in contrast to the neat PEEK, which does not melt upon exposure to the microwaves under the same parameters. Additionally, we explore 3D printing methods to fabricate a lap shear joint, where the adherends are pure polymer and the adhesive region is a polylactic acid/carbon nanofiber (PLA/CNF) composite that can be activated by microwaves. We show that solid adherends can be bonded together when a solid PLA/CNF piece is placed between the adherends and melted by microwave exposure. The microwave absorption properties and adhesive properties will be discussed.

Commentary by Dr. Valentin Fuster
2017;():V014T11A042. doi:10.1115/IMECE2017-70986.

Objective. We report the study of feasibility to produce the thing bioactive coating from experimental dental cement using pulsed laser deposition (PLD) technique.

Methods. The targets for PLD system (disks 30 mm in diameter × 5 mm thick) were sintered from micronized powder of set Alborg White Portland cement (WPC). The parameters for sintering process were chosen based thermo-gravimetric analysis and differential scanning calorimetry (TGA/DSC). The coatings were deposited by PLD on silicon substrates. The effect of laser power on coating crystallinity and morphology was evaluated by scanning electron microscope (SEM) and X-ray diffraction (XRD). The material transfer from target to substrate were evaluated by X-ray fluorescence (XRF) and X-ray energy dispersive spectroscopy (EDS).

The bioactivity of deposited films was evaluated by ability produce the hydroxyapatite (HA) layer on a surface of specimen immersed in a simulated body fluid (Dulbecco’s Phosphate-Buffered Saline (DPBS). The formation of hydroxyapatite was confirmed by SEM, X-ray energy dispersive spectroscopy (EDS), XRD and micro-Raman spectroscopy. The formation of HA was evaluated after 1, 3, 7, 14, and 21 days of immersion. Results. This study demonstrated that White Portland cement can be used as a target material for manufacturing of bio-functional coatings. The films deposited on Si substrates have mainly amorphous structure; the crystallinity of the film can be achieved by increasing the laser power. The biological performance of deposited films was tested by HA forming ability in simulated body fluid. The HA layer was formed on a coated surface after first day of immersion.

Commentary by Dr. Valentin Fuster
2017;():V014T11A043. doi:10.1115/IMECE2017-71448.

The inclusion of fillers in conventional materials has been found to have significant effect on the various properties of the parent materials. In this present work, epoxy composite was fabricated using talc and fiber glass as fillers varying the particle size and loading while the composites were then post cured at temperatures of 50°C, 75°C, 100°C, 125°C and 150°C. The compressive behavior of the composites was then quantified by conducting compression tests in a controlled environment using specimens of simple geometry. It was discovered that compressive property increased with increase in post cure temperature and particle size and a decrease with increase in filler content.

Commentary by Dr. Valentin Fuster
2017;():V014T11A044. doi:10.1115/IMECE2017-71550.

The objective of this paper is to develop in-situ structural health monitoring in polymer matrix composites using embedded bucky paper. Bucky paper based sandwich composites has been used for damage and load sensing in aerospace and defense applications due to high electrical conductivity, low density, and outstanding load sensitivity. Recent research focuses on improving mechanical, electrical, thermal properties of certain composites with improved gauge factor for sensing applications. To better understand certainly quantity strain change effects, it is essential to design composite materials and sensors for in-situ and embedded strain monitoring in composites using piezoresistance feedback.

In this paper nanocomposite bucky papers are manufactured to monitor the load and damage condition in fiber reinforced polymer matrix composites. We first investigated the fabrication of bucky papers using different nanomaterials. Then the micro-scale morphology and structures are characterized using a scanning electron microscopy. The sensing function is achieved by correlating the piezoresistance variations to the stress or strain applied on the sensing area. Due to the conductive network formed and the tunneling resistance change in neighboring nanoparticles, the electrical resistance is able to show a good correlation with the load conditions. The prepared bucky papers are embedded in composites and the sensing capability is experimentally characterized under three-point bending experiments. The characterized membrane structures have the potential to be further applied to in-situ structural health monitoring and structural state awareness during their entire service lives.

Commentary by Dr. Valentin Fuster
2017;():V014T11A045. doi:10.1115/IMECE2017-71724.

Transverse nanoindentation modulus of high performance Kevlar KM2 single fibers are experimentally studied using a nanoindenter. Researchers have investigated the transverse compression behavior of these fibers using flat punch indentation heads, in which the curved circular transverse shape of the fiber is not included, and consecutively fit the data into the analytical models to calculate their mechanical properties. During this process, the force is normalized to a point on the transverse fiber surface and the analytical model assumes a flat semi-infinite plate for substrate. Other studies consider embedding the fibers on a substrate and indenting on the transverse surface. This method bounds the fibers resulting in inaccurate measurements of their mechanical responses. There has not been an appropriate study on the transverse material properties of the Kevlar fibers determined via nanoindentation without embedding them because it is challenging to rigidly secure the fibers. Here, we have developed a methodology to secure the Kevlar fiber on an SEM puck under pretension. The tension at the fiber is calculated and accounted for in the final determination of the mechanical properties. Fibers are glued at the ends and are not embedded. The employed Vantage nanoimpactor indents the fiber radially at three different loads, namely, 2, 3, and 5 mN and calculates the mechanical properties. A Berkovich indenter is used for indentation. The Kevlar fibers are assumed transversely isotropic and have 12μm diameter measured via the Vantage optical microscope. For Kevlar KM2 fiber the experimental transverse modulus using impact nanoindenter instrument is ∼3.46 GPa. The presented experiments aim to improve our understanding of the mechanical properties of these high performance fibers on the transverse direction.

Commentary by Dr. Valentin Fuster
2017;():V014T11A046. doi:10.1115/IMECE2017-71800.

In this study, a new dynamic modulus predictive model for the Superpave asphalt-aggregate mixtures of New Mexico is developed based on the artificial neural network methodology. A total of 54 plant-produced asphalt-aggregate mixtures from all over the state were collected, compacted, cored, and sawed to cylindrical test specimens in the laboratory to conduct dynamic modulus testing at different temperatures and loading frequencies. A database containing 1,620 dynamic moduli with phase angles was then used to develop this artificial neural network based predictive model. A neural architecture with 2 twelve-node hidden layers was found to be remarkably suitable for predicting the dynamic modulus and phase angle of asphalt concrete. Statistical evaluation showed that a fairly accurate estimation of dynamic modulus can be attained by using this model.

Commentary by Dr. Valentin Fuster
2017;():V014T11A047. doi:10.1115/IMECE2017-71809.

In this study, field collected loose asphalt-aggregate mixtures were used to prepare cylindrical asphalt concrete specimen using a Superpave gyratory compactor and samples were subjected to four levels of aging. Unaged and aged samples were then tested for complex modulus, relaxation modulus, and creep compliance in the laboratory at different temperatures and loading conditions. To determine broadband characteristics, mastercurves of related viscoelastic material functions were determined by applying time-temperature superposition principle. A comparison study showed that increasing levels of aging have significant effect on viscoelastic functions of asphalt concrete. In addition, liquid asphalt binder corresponding to the asphalt-aggregate mixture was tested for complex shear modulus at various levels of aged conditions, using a dynamic shear rheometer. Results showed that even though the binder shear modulus increases significantly with aging, asphalt concrete modulus does not necessarily show similar increment.

Commentary by Dr. Valentin Fuster
2017;():V014T11A048. doi:10.1115/IMECE2017-72019.

This paper presents the application of a new technique, Magnet Assisted Composite Manufacturing (MACM), to enhance the quality of composite laminates fabricated by wet lay-up/vacuum bag (WLVB) and vacuum assisted resin transfer molding (VARTM). Towards this goal, a set of high-power, Neodymium permanent magnets, which are placed on a magnetic tool plate, is applied on the vacuum bag/lay-up. To further demonstrate the effectiveness of MACM, six-ply random mat, E-glass/epoxy composite laminates are produced under four processing scenarios: (i) Conventional WLVB; (ii) WLVB with magnetic consolidation; (iii) Conventional VARTM; and (iv) VARTM with magnetic consolidation. Applying magnetic consolidation pressure is found to be a convenient and efficient method for enhancing the overall quality of the laminates fabricated by WLVB and VARTM. For instance, in WLVB-MACM process, fiber volume fraction improves by 98% to 49% and void content reduces from 5% to less than 1.5% compared to conventional WLVB. These two factors lead to substantially increased mechanical properties of the WLVB-MACM laminates to a level comparable to those achieved by the higher-cost VARTM-MACM process.

Commentary by Dr. Valentin Fuster
2017;():V014T11A049. doi:10.1115/IMECE2017-72103.

Head protection from impact events for participants in contact sports or other activities is of current interest. Custom designed and synthesized material systems which effectively reduce the peak force transmitted to the individual and absorb a substantial portion of the impact energy are highly desirable. In applications in which recovery time of the material is not a primary concern, multiple means of energy absorption, including deformation and fracturing of the reinforcement material, may be suitable. In the present study, new composite material systems using a urethane elastomer matrix reinforced with glass and unidirectional carbon fiber rods were synthesized and subjected to compression loading along the fiber direction. The constituent fiber rods absorbed energy either through plastic deformation, buckling, or fracturing during compression loading. The effect of different reinforcement material, configuration, and length were physically tested. A cascading failure mode was achieved by embedding fibers of varying length in the matrix. This triggered successive failure events as the primary load was transferred from the longest rod to each successive shorter rod. The elastomer matrix was also experimentally characterized quasi-statically. A thin outer polymer layer further constrained the elastomer composite and allowed for fine adjustment and optimization of its crushing characteristics.

Commentary by Dr. Valentin Fuster

Safety Engineering and Risk Analysis: Failure and Forensic Analysis

2017;():V014T14A001. doi:10.1115/IMECE2017-70178.

In this presented work, a reliability sensitivity analyzing method was proposed for the resonance failures of gear-rotor systems with multiple random parameters. First, eigenvectors corresponding to the natural frequencies of a gear-rotor system governed by deterministic parameters were deduced. Mass and stiffness matrices were then decomposed into sub-matrices in the form of deterministic matrices multiplied by random parameters. Rayleigh quotient formula was utilized to derive the explicit expressions of natural frequencies of the system. Then, limit state functions of resonant failures of the system under an external load with random excited frequency was constructed based on vibration stability criterion. Reliability sensitivity analyzing method was applied to obtain sensitivities of random parameters on the resonant reliability of the gear-rotor system. Finally, a numerical case was given to illustrate the effectiveness and accuracy of the proposed method by comparing with Monte Carlo (MC) simulation.

Commentary by Dr. Valentin Fuster
2017;():V014T14A002. doi:10.1115/IMECE2017-70984.

Reliability is critical in MEMS devices design and production. Probabilistic Physics of Failure is proposed in this research for evaluation of MEMS devices reliability. Failure mechanisms are evaluated for determining the most common failures. Accordingly, a deterministic model is selected for the analysis of the life and reliability for the dominant failure mechanisms. By identification of the uncertainty sources affecting dielectric lifetime, the deterministic model is converted to a probabilistic model. This model is simulated by utilization of the Monte Carlo method. The result of life estimation is then updated using the Bayesian method.

As a case study, a framework is developed for reliability evaluation of the MEMS devices with capacitive RF MEMS switches. Results of FMEA show that stiction caused by dielectric charging, is the main failure mode in RF MEMS capacitive switches due to the presence of a high electric field across the dielectric and existence of point defects in these materials. Finally, the results of life estimation are updated using the Bayesian method.

Commentary by Dr. Valentin Fuster
2017;():V014T14A003. doi:10.1115/IMECE2017-71309.

The scientific reliability assessment is important for motor-driven compressor units, to evaluate the reliability standard, find the performance deficiency and provide references for operation and maintenance. Besides, it can reduce the test costs and accelerate the development process. Classical reliability assessment method is not suitable for the complex and reliable equipment, like motor-driven compressor units, because it is faced with the challenge of application of the multi-source information. A multi-source information based reliability assessment method is proposed in this paper. The fusion resources of this method consist of design information and operation & maintenance information. Component based and function based reliability assessment can be completed using component tests and design information. While quality evaluation based and life model based reliability assessment can be completed using operation information mainly. Finally, the unit reliability can be assessed by fusing the characteristic parameters above based on D-S evidence theory. A case study is conducted to evaluate a 20MW-class motor-driven compressor unit by this method. There are four information resources, component tests, design information, operation data and simulation data in the case. The unit reliability is assessed as 99.32% by the fusion of four reliability assessment results, acquired at different aspects. This assessment result is validated by the statistical assessment result based on long-term shutdown reports. This application points out the existing weakness in the motor-driven compressor unit and indicates directions for improving the design and operation technology. It reveals that this reliability assessment result can provide support for making a new production plan and strengthen construction of data network. Meanwhile, it has good expansibility, which may be used in more fields.

Commentary by Dr. Valentin Fuster
2017;():V014T14A004. doi:10.1115/IMECE2017-71521.

A probabilistic analysis is an approach that allows to identify whether if preventive, predictive and corrective maintenance practices are efficient for keeping the overall system safety. The implementation of methodologies that evaluate the maintenance plans are a way to improve existing programs. Promigas S.A. E.S.P. is a company that must guarantee the reliability and availability of its natural gas transmission systems to its consumers. Therefore, since 2009, the company has implemented reliability centered maintenance practices to achieve it. However, considering the current scenario of the natural gas in Colombia and according to the growth plans of the company, it is necessary to guarantee that the reliability and availability indexes remain close to 100%. To achieve the aforementioned objective, it is necessary to diagnose the current maintenance plan. We propose a hybrid methodology combining functional and probabilistic analysis to assess the maintenance plan of a natural gas transmission system, specifically a turbo-compressor power pack. The proposed methodology includes a new priorization method to identify and select critical components and its critical failure modes, through a qualitative functional and quantitative characterization of the subsystems that conform the turbo-compressor power pack. The probabilistic analyses were simulated for five time periods: one, three, six, nine and thirteen years. The results allow to conclude in terms of availability that while the maintenance plan is optimal for the first-time period, from the second time period the preventive and predictive maintenance practices must be optimized increasing resources or modifying the equipment intervention frequencies.

Commentary by Dr. Valentin Fuster
2017;():V014T14A005. doi:10.1115/IMECE2017-71739.

Thermodynamically, all damage mechanisms share common feature of energy dissipation. Dissipation is fundamental measure of irreversibility. The irreversibility is quantified in thermodynamic approach by entropy generation. Crack initiation and growth is irreversible phenomena in fatigue process, resulting entropy generation in the system. In this paper, concept of thermodynamic entropy generation is studied in crack initiation for reliability assessment. Analytical and numerical analysis are carried out to evaluate the temperature of specimen during the test. Thereafter, entropy generation is calculated by using evaluated temperature and the empirical relations (such as Morrow) as plastic work per cycle. The finite element software (ANSYS) is used for numerical simulation. It is shown that both entropy generations obtained from analytical analysis and simulation are in good agreement with experimental data. In continuation and for probabilistic analysis, a Mont Carlo simulation method is utilized to determine uncertainties and finally reliability analysis performed with entropy generation approach. As a case study, Aluminum 7075-T651 is used which has common use in airframe constructions. The result shows that the entropy generation is not constant at crack initiation. Although it has specific mean value with low dispersion at same loading condition.

Commentary by Dr. Valentin Fuster

Safety Engineering and Risk Analysis: General Topic on Risk, Safety and Reliability

2017;():V014T14A006. doi:10.1115/IMECE2017-70296.

During the storage and transportation of aviation kerosene, spill fire and explosion caused by the corrosion of pipeline or faulty operation when released and ignited, will pose a huge threat to tanks or facilities nearby. It is critical to investigate the interaction mechanism between spreading and burning of aviation kerosene spill fires to effectively plan for civil aviation safety.

In order to gain a better understanding of aviation kerosene spill fire on sloping surface, a large-scale experimental platform with varying slope of oil groove or substrate surface for aviation kerosene spill fire has been designed and built. Aviation kerosene was selected as the fuel in the continuous spill fire for different leaking rates based on the rotation of the peristaltic pump. Spill fires with the substrate slope of 0° (as the baseline case), 0.5°, 1° and 3° were conducted. The typical burning characteristic parameters of spill fire measured are included burning area, burning rate, flame front et al. It is obtained that 1) the characteristic parameters except the averaged steady burning rate for continuous aviation kerosene spill fire increases apparently with the increasing leaking rate. 2) The effect of substrate slope on the burning of continuous spill fire is significant even though there is only 0.5° variation of the slope. 3) There is a diametrically opposite findings for the averaged steady burning rates and the initial spreading rates of continuous aviation kerosene spill fire decrease with the increasing substrate slope.

Topics: Fire , Aviation
Commentary by Dr. Valentin Fuster
2017;():V014T14A007. doi:10.1115/IMECE2017-70714.

From 2000–2015, thirty-two fatalities occurred due to collisions involving mobile equipment in underground coal mining in the United States. Studies have shown that proximity detection systems (PDS) can be a potential mitigation strategy for this type of accident. However, the effectiveness of this approach for mobile equipment has yet to be fully studied or validated. Researchers at the National Institute for Occupational Safety and Health (NIOSH) evaluated the causal factors of this type of fatality. Fatal accident reports from the Mine Safety and Health Administration (MSHA) accident report database provided details to analyze and determine causal factors and to evaluate whether a PDS may have been a preventive factor in each accident. NIOSH researchers concluded that PDSs used in underground coal mines on mobile equipment which are designed to detect a miner, provide warning to the operator and other miners, and automatically stop the machine before a miner is hit may have helped to prevent 25 of the 32 or 78% of the accidents.

Commentary by Dr. Valentin Fuster
2017;():V014T14A008. doi:10.1115/IMECE2017-71386.

Conveyor systems are common mechanical handling equipment used throughout many industries to transport materials in various directions — horizontally, vertically, at an angle or around curves — and at various heights including floor-mounted and overhead systems. There are many types of conveyors including both powered and non-powered. Each type of conveyor presents its own unique sets of hazards. Although conveyors reduce injuries associated with manual material handling tasks, they can present a different set of hazards to those installing, operating or maintaining them. These hazards are typically associated with the powered mechanical motion of belts, shafts, sprockets, chains and various other subcomponents. Many industry standards are currently in use for conveyors, such as ASME B20.1, Safety Standard for Conveyors and Related Equipment. These industry standards address safe practices in the design, construction, installation, operation and maintenance of conveyor equipment.

This paper will focus on identifying and defining the hazards associated with powered conveyor systems, reviewing workplace injury data for powered conveyors and comparing with data for nonpowered conveyors to better understand the trends, quantifying many of the risks associated with conveyors, and exploring and discussing the engineering and administrative controls currently available to address these hazards. A brief look at recent updates to some of the relevant standards will be presented to guide the discussion.

Commentary by Dr. Valentin Fuster

Safety Engineering and Risk Analysis: Loss Prevention in Process Industries

2017;():V014T14A009. doi:10.1115/IMECE2017-70004.

Besides shape fidelity and internal soundness, mechanical properties have become critical acceptance criteria for investment cast parts. These properties are mainly driven by the chemical composition of cast alloy as well as process parameters. It is however, difficult to identify the most critical parameters and their specific values influencing the mechanical properties. This is achieved in the present work by employing foundry data analytic based on Bayesian inference to compute the values of posterior probability for each input parameter. This is demonstrated on real-life data collected from an industrial foundry. Controlling the identified parameters within the specific range of values resulted in improved mechanical properties. Unlike computer simulation, artificial neural networks and statistical methods explored by earlier researchers, the proposed approach is easy to implement in industry for controlling and optimizing the parameters to achieve the desired range of mechanical properties. The current work also shows the way forward for building similar systems for other casting and manufacturing processes.

Commentary by Dr. Valentin Fuster
2017;():V014T14A010. doi:10.1115/IMECE2017-70459.

This paper presents a real world rollover accident involving a common make and model sport utility vehicle, or SUV, analyzed using a well-validated, publicly available finite element analysis, or FEA, model of the same vehicle. The FEA model was utilized to evaluate the loading conditions of a real-world rollover accident that had previously been reconstructed using standard engineering techniques. Iteration of the conditions of the finite element, or FE, simulation to match the damage observed in the subject vehicle provided a quantification of the rollover crash loading.

Once the damage pattern of the real world accident was achieved in the FE simulation, reinforcement techniques utilizing changes to the material properties and thicknesses of selected roof structure components were used to represent a re-designed roof. The re-designed roof improved intrusion resistance by more than 80% with a minimal weight penalty.

Topics: Design , Roofs
Commentary by Dr. Valentin Fuster
2017;():V014T14A011. doi:10.1115/IMECE2017-71139.

The importance of safety regulations and risk assessments in the chemical process of industry has been doubled by the increasing number of accidents in petroleum storage facilities. Control of critical situations and conditions against risks require appropriate planning, collection of valid information of possible scenarios and utilization of proper assessment techniques.

In this study, by combining numerical simulation techniques, mathematical and experimental data and utilization of commercial software, the risks of a Tabriz refinery gasoline tank (as a case study) are investigated for a total release of the reservoir scenario within a specified period of time, as the worst case. The effect of the environment temperature is evaluated on the progression of the scenario. Based on comparison of the results of numerical simulations of pool fire, and vapor cloud explosion with simulation results based on empirical-mathematical models, it can be concluded that, there are significant differences between the results in the vicinity of the boundary conditions; however, with increasing distance from the center of the accident point, this difference decreases markedly.

Commentary by Dr. Valentin Fuster
2017;():V014T14A012. doi:10.1115/IMECE2017-71543.

The integrity of pipelines during the transportation of flammable fluids requires the development or implementation of repair/rehabilitation techniques that ensure their performance over time in a cost-effective way, due to the high and potential costs that result from failure (loss of life, damage to property, and penalties from service interruption). In this work, a review of the typical defectology found in gas transport steel pipeline systems is described. As part of the review, the current status of technologies and techniques implemented for the repair and rehabilitation of pipes in the Oil & Gas industry is presented. Based upon the available solutions, a revision is proposed from the regulations and standards which define the implementation of these type of solutions for the natural gas transport pipelines. A comparative summary that includes mechanized or induced defects on pipes for further study and performance measurement of the implemented solutions is presented. Decision factors to be considered in the selection process are displayed according to a particular gas transportation operator’s requirements and general criteria. These factors take into account the required considerations with respect to the pipe material, effect on environments, skill requirements for installation, the in-service installation capability, and the final selected method.

Commentary by Dr. Valentin Fuster
2017;():V014T14A013. doi:10.1115/IMECE2017-71862.

Natural gas transmission infrastructure is a large-scale complex system often exhibiting a considerable operating states not only due to natural, slow and normal process changes related to aging but also to a dynamic interaction with multiple agents overall having different functional parameters, an irregular demand trend adjusted by the hour, and sometimes affected by external conditions as severe climate periods.

As traditional fault detection relies in alarm management system and operator’s expertise, it is paramount to deploy a strategy being able to update its underlying structure and effectively adapting to such process shifts. This feature would allow operators and engineers to have a better framework to address the online data being gathered in dynamic on transient conditions.

This paper presents an extended analysis on WARP technique to address the abnormal condition management activities of multiple-state processes deployed in critical natural gas transmission infrastructure. Special emphasis is made on the updating activity to incorporate effectively the operating shifts exhibited by a new operating condition implemented on a fault detection strategy. This analysis broadens the authors’ original algorithm scope to include multi-state systems in addition to process drifting behavior.

The strategy is assessed under two different scenarios rendering a major shift in process’ operating conditions related to natural gas transmission systems: A transition between low and high natural gas demand to support hydroelectric generation matrix on severe tropical conditions. Performance evaluation of fault detection algorithm is carried out based on false alarm rate, detection time and misdetection rate estimated around the model update.

Commentary by Dr. Valentin Fuster

Safety Engineering and Risk Analysis: Reliability Methods

2017;():V014T14A014. doi:10.1115/IMECE2017-70084.

The fatigue failure of metal components is due to cyclic fatigue loading. The typical cyclic fatigue loading spectrums described in the literature includes only a few simple cyclic loadings such as a constant amplitude of cyclic fatigue loading with a given cycle number, several constant amplitudes of cyclic fatigue loadings with given cycle numbers, and a distributed stress amplitude of a cyclic stress with a given cycle number or an infinite life. The systematic description of cyclic fatigue loading spectrums is necessary and wasn’t presented in the literature. This paper will present a systematic description of all possible types of cyclic fatigue loading spectrums, which includes 6 different cyclic fatigue loading spectrum models. The P-S-N curve fatigue theory is widely accepted not only for describing the fatigue test data, but also for estimating the reliability of components under cyclic fatigue loading spectrum. However, the reliability calculation of a component under several distributed stress levels with corresponding given cyclic numbers has not been solved according to the literature review. This paper presents a new approach to estimate the reliability of components under such cyclic fatigue loading spectrum. With the contribution of this paper, the P-S-N curve fatigue theory now becomes a complete fatigue reliability theory and can be used to estimate the reliability of components under any type of cyclic fatigue loading spectrum.

Topics: Fatigue , Reliability
Commentary by Dr. Valentin Fuster
2017;():V014T14A015. doi:10.1115/IMECE2017-70177.

Vibration reliability analysis of gear sets considering various kinds of nonlinear random factors is essential for the safety of gear driven systems. In this paper, a rational definition of gear sets vibration reliability was presented at first by taking all kinds of vibration responses including displacement, velocity and acceleration into account uniformly by treating them as a series system with statistically independent components. According to the given definition, a systematic analyzing scheme for the vibration reliability of gear sets was proposed. Vibration reliability estimated via the analyzing scheme would make it conservative but more safely in design of gear driven systems. Subsequently, both analytic and numerical methods for gear sets vibration response reliability estimation were carried out based on the proposed analyzing scheme. The analytic method is suitable for the situations that the vibration responses of gears sets under random circumstances are stationary stochastic responses. While, the numerical method named Multi-crossing Monte Carlo Simulation (MULCMCS) can well solve the reliability estimating problems even when the vibration responses of gear sets are nonstationary stochastic processes. Finally, for illustration, a numerical case of analyzing the vibration response reliability of a single degree-of-freedom (DOF) gear set was given to demonstrate the effectiveness of the MULCMCS method.

Commentary by Dr. Valentin Fuster
2017;():V014T14A016. doi:10.1115/IMECE2017-70527.

This paper discusses conceptual engineering approaches to assessment of risk to energy systems from global climate change. It is critical for energy system stakeholders, especially nuclear sector, to identify and manage the vulnerabilities of energy systems to climate change and exposure to extra stresses. This paper provides an overview of the risk assessment framework applicable to safety, health and widespread prolonged loss of electric power risks, along with examples of tool and techniques used. Two major concerns are gradual climate change risks and short-term sustained weather extremes that may be endured by the energy systems. Risk assessment and management techniques (qualified and quantified) are discussed for both of these conditions. For the long-term gradual climate change, the physics-of-failure approach is proposed to quantify the risks of slow but extensive degradation of critical equipment and structures of the energy systems. For faster evaluation, the qualified methods like FMEA, HAZOP and simpler quantified methods like layer of protection analysis (LOPA) are recommended. Resilience of the energy system is potentially analyzed by estimation of the system risk due to the impacts of climate change. Because climate change can create conditions that will negatively impact the energy sector, resilience becomes increasingly important. The paper also proposes the risk margin approach and stress-strength failure modeling technique as two possible methods of analyzing short-term sustained extreme weather conditions considering the built-in capabilities and safety margins of human operators, components and structures. Energy systems with small or no extra margin for safe production of power will be most vulnerable to adverse exposures from weather extremes potentially created by global and ecological changes. The assessments are accompanied with the uncertainty of various sources.

Commentary by Dr. Valentin Fuster

Safety Engineering and Risk Analysis: Testing for Product Reliability and Safety

2017;():V014T14A017. doi:10.1115/IMECE2017-70381.

The application of lightweight materials for tanks for transportation appears promising. Besides saving weight and therefore transportation costs, new complex geometries that depart from common cylindrical shapes of steel tanks can be manufactured. For transportation of dangerous goods, fire and explosion safety must be maintained to prevent accidents with serious consequences. In this work the fire behavior of lightweight tanks made from glass fiber reinforced plastics (GFRP) with complex geometries is investigated. Pretests on intermediate scale GFRP plates are conducted to identify suitable fire protection systems and surface treatments for composite tanks. The fire resistance is shown to be improved by addition of fire protective coatings and integrated layers. Finally, a complex rectangular GFRP tank with a holding capacity of 1100 liters is fire protected with an intumescent fire coating. The tank is filled up to 80 % with water and burned under an engulfing fully developed fire. It was shown that the intumescent layer could expand before the decomposition of the resin occurred. Furthermore, the adhesion between tank surface and coating was maintained. The structure could withstand a fire for more than 20 min.

Commentary by Dr. Valentin Fuster
2017;():V014T14A018. doi:10.1115/IMECE2017-70431.

This paper presents a case study of an injury producing post-crash fire as well as testing methods to evaluate bulkhead pass through seal fire resistance and retention. In the subject crash, engine compartment fluids were released and ignited. The burning fluids entered the occupant compartment through a bulkhead pass through, resulting in rapid fire propagation and severe occupant injuries before extrication could be completed. A burn testing methodology was developed and used to evaluate the ability of the subject seal design to prevent flames and fluids from entering the occupant compartment. A retention testing methodology was also developed and used to evaluate a variety of seal designs.

Commentary by Dr. Valentin Fuster
2017;():V014T14A019. doi:10.1115/IMECE2017-72676.

Operators of personal watercraft (PWC) can perform maneuvers that may result in riders separating from the moving watercraft; the tested hypothesis was whether substantial brain injury concurrent with substantial facial and skull fractures can occur from contact with the PWC during a fall. The present study reports the potential for AIS2+ facial/skull fractures and AIS2+ traumatic brain injury (TBI) during a generic fall from the PWC in the absence of wave-jumping or other aggressive maneuvers. While it is well known that PWC can be used for wave-jumping which can result in more severe impacts, such impacts are beyond the scope of the present study because of the wide variability in occupant and PWC kinematics and possible impact velocities and orientations. Passenger separation and fall kinematics from both seated and standing positions were analyzed to estimate head impact velocities and possible impact locations on the PWC. A special purpose headform, known as the Facial and Ocular CountermeasUre Safety (FOCUS) device was used to evaluate the potential for facial fractures, skull fractures and TBI. Impacts between the FOCUS headform and the PWC were performed at velocities of 8, 10, and 12 miles per hour at 5 locations near the stern of a PWC. This study reports impact forces for various facial areas, linear and angular head accelerations, and Head Injury Criteria (HIC). The risk for facial fracture and TBI are reported herein. The results of this study indicate that concurrent AIS2 facial fractures, AIS2+ skull fractures, and AIS2+ TBI do not occur during a simple fall from a PWC.

Topics: Testing , Wounds , Risk
Commentary by Dr. Valentin Fuster

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