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ASME Conference Presenter Attendance Policy and Archival Proceedings

2014;():V003T00A001. doi:10.1115/ESDA2014-NS3.
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This online compilation of papers from the ASME 2014 12th Biennial Conference on Engineering Systems Design and Analysis (ESDA2014) 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to ASME’s conference presenter attendance policy, if a paper is not presented at the Conference, the paper will not be published in the official archival Proceedings, which are registered with the Library of Congress and are submitted for abstracting and indexing. The paper also will not be published in The ASME Digital Collection and may not be cited as a published paper.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

Engineering Systems

2014;():V003T10A001. doi:10.1115/ESDA2014-20064.

As the energy landscape changes globally with the development of tight oil and gas resources, questions about the rail safety and tighter regulations around safety and environment, energy insiders are asking the question; are pipelines still the safest way to transport energy? In a recent study conducted by T.D. Williamson (TDW) (1) this paper uncovers some current industry trends, drivers and restraints that will shape the pipelines landscape for the future. The study looked at regional trends, technology applications and future project developments in the pipelines arena and how this is influencing how pipelines are being designed, installed and utilized.

The study identified that there were four distinct pipeline “themes” over the pipeline life cycle, which comprise:

• Infrastructure – pipeline new build for growth, replacement and expansion,

• Integrity Management – management of the integrity for new and existing pipelines,

• Flow Assurance & Throughput – optimizing throughput and uptime for new and existing pipelines,

• Management of Human Capital – acquiring, developing and retaining competent people or outsourcing.

The paper will discuss how these needs imbedded in these themes are met or, as in some cases, unmet.

The paper also looks at developments in materials for new pipelines, pipeline monitoring and leak detection (from cables to dogs to, unmanned vehicles), newer products that are being shipped (from higher hydrogen content methane gas to carbon dioxide from capture schemes to diluted bitumen from the oil sands), the impact of “big data” (from Mb to Yb), and how operators are looking to manage emergencies (from spill response to emergency planning and operational readiness).

This paper will compare safety records for energy transportation as well as the new demands being put on energy companies that will propose an answer to the question posed in the title.

Topics: Pipelines
Commentary by Dr. Valentin Fuster
2014;():V003T10A002. doi:10.1115/ESDA2014-20099.

In this study, we adopt a dual power system for extension (DPES) operation by combining the existing power system of an electric vehicle with a hydrogen fuel cell. This was to enhance the durability of the electric vehicle and reduce the inconvenience of battery charging. The lithium battery acts as the primary power source and has real-time monitoring of its state of charge (SOC), while the hydrogen fuel cells act as the auxiliary power supply. The auxiliary power can be used either directly or for charging the lithium battery while the vehicle is in its idle state. The dual power system is coupled with a dual-mode motor controller and energy management system. This study aims to apply the dual power system on the electric vehicle using hydrogen fuel cells. We designed a simulation platform for real driving conditions using Labview to send and receive control commands. In this study, we simulated the road cycles of the Economic Commission for Europe (ECE-40), Japanese legislative cycle (JP10) and the World-wide Motorcycle Emissions Test Cycle (WMTC), using Proportional-integral Control (PI) for automatic tracking and employing engineering error analysis to determine the most suitable PI parameter values for the simulated system. The results showed that using a fixed 100 W fuel cell could enhance the operation time up to 21 %, 21 %, and 14 % for the road cycles of the ECE-40, JP10, and WMTC, respectively. Due to the required features of an actual vehicle, we also designed an energy limiting system to manage the driver-controlled electronic throttle by controlling the instantaneous and maximum power output of the motor in order to achieve savings in energy consumption, increase its operation time, protect the system, and enhance its durability.

Commentary by Dr. Valentin Fuster
2014;():V003T10A003. doi:10.1115/ESDA2014-20135.

Magnetorheological (MR) brake technology, owing to its reduced response delay, has generated interest for its potential as substitute to conventional hydraulic brakes in a road vehicle. Recently, few investigations have been carried out to assess its application for a mid size car. Finite element studies and experimental investigations have been carried out by researchers. However, reliability aspect of these brakes doesn’t seem to have been explored as yet.

This paper makes an attempt to present findings of the qualitative reliability studies on MR brake system for vehicular application. Results of Failure Mode Effect Analysis (FMEA) and Fault Tree Analysis (FTA) have been presented and discussed subsequently. Findings of this analysis, it is believed, shall complement the design process and make it fool proof. It also provides basis for further quantitative reliability estimation, in case of availability of failure data of MR brake system components.

Commentary by Dr. Valentin Fuster
2014;():V003T10A004. doi:10.1115/ESDA2014-20141.

A production line is a fundament of modern high scale FMCG industry. The performance of the line depends on various factors, out of which breakdowns, cleanings and changeovers play the most important role. The paper describes the idea of modeling production line performance by its decomposition into discrete subsystems. Every machine or workstation together with preceding buffer constitute a single subsystem, which is characterized by statistical distributions of time to repair, time between failures, processing speed and capacity. Time dedicated for cleaning and changing format parts between different production batches is also considered in the model. Subsystems are connected with each other by conveyors. The model was simulated by the given time step. In order to verify the simulation results, the data from the real production line were compared and used for adjusting the parameters of the model. The described specimen consisted of six workstations connected with conveyors. There was one high capacity buffer between the second and third station. The efficiency of the whole line as well breakdown time characterizing every machine was captured by data acquisition system. Based on the given data, the parameters of statistical distributions of time to repair and time between failures were estimated by approximation to known distributions. In addition, statistical distributions of cleaning and changeover time were derived in order to provide general performance of the production line. Genetic algorithm was introduced to optimize the line parameters in order to achieve higher efficiency and to identify potential bottlenecks.

Commentary by Dr. Valentin Fuster
2014;():V003T10A005. doi:10.1115/ESDA2014-20255.

Stability of a gantry crane was a challenge in its structure design. A new risk-based stability assessment approach was proposed in this paper. Analytical method was introduced firstly, and then finite element method was adopted to evaluate the stability of square bar. In order to verify the finite element models, results of buckling analysis were compared with the results of analytical method. Secondly, this finite element analysis was applied in stability assessment of a gantry crane, and through parameterized analysis risk elements were identified. Finally, risk-based stability assessment was applied to this gantry crane, and neural network algorithm was adopted to evaluate the risk elements which were defined by finite element analysis. The evaluating results were well consistetent with statistical data, which indicated this risk-based stability assessment approach was reliable which showed a potential in engineering application.

Commentary by Dr. Valentin Fuster
2014;():V003T10A006. doi:10.1115/ESDA2014-20281.

The design of high-sensitive hydrophones is one of the research interests in underwater acoustics. Due to progress of micro- and nanotechnology the most attention of researchers is attracted by the transducers that use the micro-electromechanical system (MEMS) concept. Piezoelectric micro-machined ultrasonic transducers (pMUTs) present a new approach to sound detection and generation that can overcome the shortcomings of conventional transducers. For accurate ultrasound field measurement, small size hydrophones which are smaller than the acoustic wavelength are required for providing an omnidirectional response and avoid spatial averaging.

This paper presents some results of multiobjective optimization for membrane-type piezoceramic MEMS based transducers. We investigate the miniaturized membrane-type sensor with perforated holes in the active PZT and intermediate membranes, with the protective plates and a vacuum chamber. An influence of the protective plate elastic and viscous properties, the dimensions and the relative area of the perforated holes on the sensitivity’s frequency response of the hydrophone was studied for the broadening and equalizes the operating frequency band. We optimize these key parameters using the Pareto approach with the finite element (FE) model of coupled piezoelectric-acoustic problem. Finally, the set of optimized hydrophone structures and some examples of obtained sensitivity frequency response are demonstrated.

Commentary by Dr. Valentin Fuster
2014;():V003T10A007. doi:10.1115/ESDA2014-20370.

Iron cast machining is nowadays preceded by the process of marking out, ascertaining appropriate casting precision and size of machined surface surpluses. The procedure entails delineating (etching) boundaries of the nominal machining surpluses upon the raw cast surfaces. Their size, standardized according to the ISO 8062 certificate, depends on maximal cast dimensions and the casting method applied. The characteristic machining surplus size of the hereby investigated typical industrial casts ranges between 6 and 8 mm. As casting accuracy is determined by individual foundry standards, the actual machining surplus size values commonly differ from the nominal ones. Thus, in order to ascertain appropriate machining of a given cast, variable surplus distribution is warranted, resulting in actual surplus size values of 2–12 mm.

Inherent to the iron casting procedure are variable hardness values within the casting wall cross-section, with the outer wall surface (directly contingent to the mold that rapidly cools the cast) characterized by the highest hardness value, decreasing incrementally towards its center. Verification of surface hardness values takes place after machining and involves selected work surfaces (e.g. base areas of a runner block). Excessive machining of oversized surpluses within the verified areas results in insufficient hardness of their surfaces.

Bearing the above considerations in mind, optimization of surplus distribution was attempted, relating to most advantageous hardness values of selected cast work surfaces. The investigation was conducted under industrial conditions, upon milling center framework casts. The selected work surfaces were processed gradually; the surface hardness was measured after each machining step. Results thus obtained were implemented for further machining surplus optimization of equivalent casts.

Commentary by Dr. Valentin Fuster
2014;():V003T10A008. doi:10.1115/ESDA2014-20374.

Generally product lifecycle management (PLM) is characterized as an integrated management process of product information and related processes across the product lifecycle. PLM affects development time of product and optimize the cooperation of all components of the development process of products. Therefore attention has to be paid to this fact in production and research. Processes across the entire product lifecycle management are complex and it is difficult to support various levels of cooperation. It is necessary to identify technological solutions to facilitate the implementation of PLM systems into processes of product life cycle. In the paper is presented derivation of technology solutions for PLM (product lifecycle information modeling and management, product lifecycle knowledge management, design chain management, product lifecycle process management, product trade exchange, collaborative product service and product lifecycle portal for stakeholder, developer, customer, manufacturer and supplier) and applications of advanced information technologies for implementation of PLM. In the paper is also described the technological solution which was developed to meet industrial requirements and obtain long term sustainability in today’s highly competitive market. Currently, still only a few small and medium-sized enterprises (SMEs) uses real benefits that PLM offers. The small and medium-sized enterprises also try to implement those technologies but, despite their flexibility, they have difficulties in structuring and exchanging information. Enterprises also have problems in creating data models for structuring and sharing product information, especially in the context of extended enterprises. It is caused by several factors that may have information, technical and financial character. Article refers and highlights the benefits that PLM brings by extension of PLM into so called “Closed-Loop Lifecycle Management (CL2M)”. It also describes the major barriers to the implementation of PLM in SME and propose possible solutions.

Commentary by Dr. Valentin Fuster
2014;():V003T10A009. doi:10.1115/ESDA2014-20393.

In this paper, we present a framework to define, visualise, analyse and manage a design factory in a complex engineering environment. Design engineering is the core of product development and provides high leverage in cost, quality and time to market. Lean principles can be applied to gain these improvements to the design management system. However, unlike manufacturing and operations, design processes are inherently non-linear and iterative in nature. In addition, design outputs, queues and work in progress are not visible and tangible. This creates challenges in applying lean principles in the design environment. To alleviate these issues design engineering is treated as a factory and its key steps are mapped by using the gated review process. The inputs and outputs of the design factory system are identified and employed to create an effective productivity improvement dashboard. The gated review process steps are used to understand the flow of design solutions. Lean principles and structured root-cause analysis is used to create a system to visualise, analyse and manage the design factory.

Topics: Design
Commentary by Dr. Valentin Fuster
2014;():V003T10A010. doi:10.1115/ESDA2014-20401.

The repeated failure of Agitator in the Phosphoric acid Reactor in MPC was a major incident causing high downtime and production loss. While doing the root cause analysis of this “Class A” incident many causes not considered in normal agitator design were considered and analyzed. This paper lists such special cases and the proposed solutions and calculations to be incorporated in design of critical systems with varying process fluid parameters for different applications. Agitators constitute almost 20% of rotating equipment in a fertilizer and similar plants but are given less priority compared to others until a severe failure happens. There are no standard analytical design criteria for agitator design due to large variations and uncertainties in the process conditions in the reactor or tank. Most designs are left to the EPC companies using preformatted design models based on experimental results, on the combination of few variables. (Like Power Number, Pumping Number, Geometrical ratios etc.) However, none these models considers the fluid flow conditions which changes inside the reactor which affects the agitator design in many ways like Localized flow, non-homogenous fluid, solid contents, Liquid additives or recycling etc. which can cause much higher alternating forces and bending stresses at the joints holding the blades causing fatigue and other failures. This paper gives more quantitative design calculations to determine the forces acting on the agitator and blades as listed above which can be used in similar application even with different fluids.

Commentary by Dr. Valentin Fuster
2014;():V003T10A011. doi:10.1115/ESDA2014-20403.

This work is related to the design and development of instrumentation, data acquisition and graphical user interface of Photovoltaic driven Reverse Osmosis system for monitoring and performance evaluation purposes. Installed PV system comprises of 12 PV panels, trackers, batteries and inverter whereas RO system is equipped with pre filters, pumps, energy recovery devices and filtration membranes. Proper instrumentation is carried out in PV system to measure the irradiation, temperatures, voltage and current at various points. Moreover various sensors are used to measure the pressures, flows, salinities at RO unit. Signal conditioning circuits are designed to adjust sensor output signals for computer interface. A simple moving average filter is used to suppress the measurement noise. The experimental investigation of PVRO system is carried out by using LabVIEW interface capabilities. The developed system reveals and stores the pronounced impact of measured variables on the PV output power and specific energy consumption of the RO filtration system. The online data display in multi-scale window frame is very informative for system operation and analysis. During the experimental run of PVRO system using the developed DAQ system, the PV system generated 7.5kWh of energy during the whole day operation. Feed water having 7100ppm salinity and its flow rate was set to 850 lit/hour by adjusting the RPM of the high pressure pump. Clean water flow rate is recorded to be at 465 lit/hour having salinity of 115 ppm during the RO operation. Specific energy consumption of RO system comes out to be 2.083kWh/m3 for 7100ppm salinity of feed water.

Commentary by Dr. Valentin Fuster
2014;():V003T10A012. doi:10.1115/ESDA2014-20422.

Competing supply chain networks all around the globe are under scrutiny due to ever-growing demand for service improvement and cost reduction. A major field of action in this respect is the realization of real-time monitoring means for supply chain processes including a constant comparison of the respective progress status with the planning guidelines and the best possible management of deviations and exceptions.

Control towers have been named as the future tool of supply chain monitoring for quite a while. They are defined as decision-support systems merging different data streams from various subordinate levels and displaying the consolidated information at a higher level for the purpose of monitoring and control of processes while pursuing the goal of optimal process operation. Contrary to the technological constraints of the past which prevented a continuous and fully transparent real-time monitoring of supply chain processes, innovative evolving so-called Future Internet technologies enable genuine transparency and the handling of exceptions in a timely and cost-efficient manner nowadays. With the help of such technologies, newly designed and built control towers are supposed to assist actors on the planning and execution levels of their respective supply chain networks in their decision-making in case of relevant deviations or exceptions. This again raises the market acceptance of such control towers.

This paper presents a novel approach to the functional principle of Future-Internet-based control tower solutions and describes the different components therein. Especially, the incorporation of manifold information sources from the Future Internet technologies for the purpose of real-time monitoring and control of supply chain processes is highlighted in the paper.

Commentary by Dr. Valentin Fuster
2014;():V003T10A013. doi:10.1115/ESDA2014-20436.

Application of Structural Integrity Concepts to RF NPP piping and equipment have started in Russia in the beginning of 1990s from requirements to Leak Before Break (LBB) calculation studies adopted by regulatory body. Results of first practical LBB Concept application to RF NPP piping have been reported at Lyon LBB Conference in year 1995.

Experience of LBB Concept practical application in Russia during 1990s formed strong basis for issuing comprehensive guideline RD 95 10547-99 which stated LBB Concept basic principles and requirements applicable to RF NPPs with Light Water Reactors (LWR) at all stages of Life Cycle: design, commissioning and operation. Requirements of RD 95 10547-99 guideline have been in good correspondence to classic LBB principles used in many European countries, USA, Japan and to IAEA Technical Documents as well.

RF NPP piping operation experience analysis have revealed necessity of producing more general methodology — Break Preclusion (BP) Concept — to substantiate structural integrity of piping potentially susceptible to active degradation mechanisms like Flow Accelerated Corrosion (FAC), Intergranular Stress Corrosion Cracking (IGSCC), etc. BP and LBB Concepts are based on the same major principles: (a) quality of design, manufacturing, assembling, (b) monitoring of degradation and operating conditions, (c) enveloping loading conditions with respect to maximum design loads, (d) calculation and experimental substantiation of failure according to LBB scenario. LBB Concept requires full implementation of principles (a)÷(d) and BP Concept allows to achieve balance in implementation of principles (a) and (b) while principles (c) and (d) should be fully implemented.

Memorandum of 8th International Scientific and Technical Conference “Safety of VVER NPPs” in year 2013 stated as a 1st priority goal to substantiate structural integrity of main components for Long-Term Operation (LTO) during 60–80 years. Actual regulatory demands to operating NPPs also produce strong demand to provide structural integrity arguments for safety important piping and equipment as a part of periodic safety justification of NPP Unit needed for license extension.

Peculiarities of structural integrity concepts application to safety important piping and equipment at different stages of NPP Unit Life Cycle (design. commissioning and operation) are discussed in paper with emphasis on technical measures providing conditions for effective degradation monitoring and prevention during LTO. Perspectives of regulatory documents improvement are also discussed.

Commentary by Dr. Valentin Fuster
2014;():V003T10A014. doi:10.1115/ESDA2014-20437.

This paper presents SBAT, a tool framework for the modelling and analysis of complex business workflows. SBAT is applied to analyse an example from the Danish baked goods industry.

Based upon the Business Process Modelling and Notation (BPMN) language for business process modelling, we describe a formalised variant of this language extended to support the addition of intention preserving stochastic branching and parameterised reward annotations. Building on previous work, we detail the design of SBAT, a software tool which allows for the analysis of BPMN models. Within SBAT, properties of interest are specified using the temporal logic Probabilistic Computation Tree Logic (PCTL) and we employ stochastic model checking, by means of the model checker PRISM, to compute their exact values.

We present a simplified example of a distributed stochastic system where we determine a reachability property and the value of associated rewards in states of interest for a real-world example from a case company in the Danish baked goods industry. The developments are presented in a generalised fashion to make them relevant to the general problem of implementing quantitative probabilistic model checking of graph-based process modelling languages.

This paper contains three key elements:

1. SBAT description.

2. Case company description.

3. Using SBAT on the case company.

The paper concludes by indicating SBAT’s practical applicability and suggests further research directions.

Commentary by Dr. Valentin Fuster
2014;():V003T10A015. doi:10.1115/ESDA2014-20457.

The present study deals with vital aspects of technological assembly process modeling and simulation based on application of the MTBF (Mean Time Between Failures) parameter, as exemplified upon experimental assembly of an automobile disc brake caliper unit. The proposed simulation model of the analyzed assembly work cell is hereby expounded upon. The paper further presents the outcomes and conclusions of the undertaken experimental procedure.

Commentary by Dr. Valentin Fuster
2014;():V003T10A016. doi:10.1115/ESDA2014-20473.

This paper discusses the static and dynamic stability analysis of rack or frame computer/server products during shipping and relocation. The static stability is the ability of server products to resist tipping over on a typical raised floor in a datacenter or when it is installed in its operational product environment. The dynamic stability is the ability to resist tipping over when a velocity change occurs during re-location either on flat or inclined planes. The product consists of a frame or a rack in which components such as processor units, input-output units and power supplies are installed.

The static stability analysis presented here calculates the tip over threshold angle, which is the maximum angle of an inclined plane on which the product can be placed without tipping over. The location of the installed components in a frame, the dimension and weight of the installed components, and the dimension of the product dictate the overall static stability of the product. Specifically, those parameters affect the location of the center of gravity of the product and the tip over threshold angle. The tip over threshold angle is a critical parameter influencing the dynamic stability of the product..

The dynamic stability of an unpackaged product moving on casters can be calculated using the conservation of mechanical energy principle. Finite element modeling is a good way to evaluate the dynamic stability of a product during manual handling or mechanical handling; for instance, on a forklift. The objective of the finite element modeling is to provide guidelines on the maximum speed, minimum radius curvature, and safe turning speed of a forklift when transporting a product.

The main objective of the analysis presented here is to provide a method for analyzing the static and dynamic stability of a rack style computer server product during shipping, relocation, and handling.

Commentary by Dr. Valentin Fuster
2014;():V003T10A017. doi:10.1115/ESDA2014-20512.

In this paper, a framework based on Augmented Reality (AR) and a mobile device is proposed for monitoring mechanical components during fatigue tests. This solution enables the user to move around and to inspect the component through AR from different points of view. In addition, the framework proposes a solution to estimate in real time the crack growth and to visualize it directly onto the component. A user application is developed according to the proposed framework and it is used for case studies of fatigue test for adhesively bonded joints.

Commentary by Dr. Valentin Fuster
2014;():V003T10A018. doi:10.1115/ESDA2014-20520.

In this paper, an optimal control strategy (i.e., offset settings system) based on the new Multi-objective Particle Swarm Optimization with Differential Evolution (MOPSO-DE) technique is developed and presented. The MOPSO-DE algorithm is used for calculating the optimal positions (i.e., offset settings) for the cutting tools in lathe machines. This optimal control strategy yields interesting results without a need to go through the complex mathematical modeling of the lathe system. The proposed technique is validated considering a real-world industrial system. This strategy is designed to take an action every 20 pieces, and it takes only 2.5 sec to run the code and optimally calculate the new settings. The control strategy is implemented using two high precision linear stepper motors. By implementing the new optimal control strategy, the estimated number of the defective pieces per day can be reduced by 85%.

Commentary by Dr. Valentin Fuster
2014;():V003T10A019. doi:10.1115/ESDA2014-20533.

The majority of pressure tunnels are designed with pervious concrete lining, considering limited parameters (quantity and opening) equidistributed cracks. In general, according to the requirements of building specifications admissible seepage losses from tunnel shall not exceed 1% of HPP design discharge. As shown by the operation of HPP’s the value of seepage losses is in reality much higher than the acceptable one.

The Inguri HPP pressure tunnel (15 km in length and 9.5 m in diameter) passes in complex geological conditions. The maximum value of pressure at the beginning and end of tunnel is, correspondingly, 110–175 m, while the water level variability in the reservoir is 90 m.

The main characteristic of the structure of diversion tunnel is that in the main part of its length it is represented as a single complex: concrete lining (0.5 m thick) with strengthened grouting zone (6 m deep). Such design decision replaced more traditional structures, e.g. strengthened concrete, combined or metal linings.

The internal pressure of tunnel is borne by the monolithic mass formed by reinforcement grouting. Thereby lining operation is completely dependent on the parameters characteristic for the zone of strengthened grouting (resilient backpressure and perviousness), which must satisfy design values. Thus reinforcement grouting, along with filling grouting are integral parts of pressure tunnel, without which the operation of structure is practically impossible.

At the initial stage of operation (in 1985, at the low level in the reservoir and under the impact of the increase of pressures from massif the loss of lining stability (of the wall and inverted arch) occurred. Presently, based on general assessment the seepage losses developed from tunnel reach up to 10 m3/sec, which thrice exceed the design ones.

As a result of rehabilitation works (massif grouting and shotcrete lining) conducted in 2006 in certain sections of tunnel seepage losses were temporarily reduced. Subsequently seepage losses increased again due to the development of erosive leakage processes in massif.

In the present work calculations were conducted of the seepage parameters and stress condition of the “tunnel-massif” system during filling and discharge of reservoir using a static-seepage coupled scheme, in which a complex geological structure of massif (anisotropy, presence of cracks), the deformation of massif and seepage body force developed in it are taken into consideration. The processes developed during operational period, including depression surface enlarged and the loss of concrete lining stability, are also analyzed.

Inguri HPP is Georgia’s powerful energy object (capacity – 1300 MW, design head – 450 m). Clearly the reduction of seepage losses has a great impact on power generation. In future the rehabilitation of tunnel is envisaged, as alternative options of which shotcrete lining is viewed, the same with strengthening grouting zone and stressed lining (with expanding cement). The present work presents part of the research.

Commentary by Dr. Valentin Fuster

Heat Transfer and Thermal Engineering

2014;():V003T12A001. doi:10.1115/ESDA2014-20005.

In the present paper, simulation for shell and tube heat exchanger investigated using CFD techniques. Numerical simulations of the turbulent, three-dimensional fluid flow and heat transfer are performed using Ansys Fluent 6.3. The effect of friction characteristics on the model of heat exchanger is discussed. A RNG κ-ε turbulence model with non-equilibrium wall function and 2nd order upwind is used. The present model is validated with the experimental literature and show a good agreement. The numerical results of the present study predict reasonably agree well with available correlations. Finally the present study model can be used to model a shell and tube heat exchanger with a satisfactory accuracy level in predictions.

Commentary by Dr. Valentin Fuster
2014;():V003T12A002. doi:10.1115/ESDA2014-20052.

This paper presents a dynamic model for simulating the heat generation and the impact of Phase Change Materials (PCMs) on the maximum temperature in LiFePO4 battery cells. The model is constructed by coupling a one-dimensional electrochemical model with a two-dimensional thermal model and fluid flow model in a battery pack array. Two different realizations are analysed and compared, one when the heat equation is considered for the PCM (no-flow case) and another one when fluid flow is considered. The results show that by using PCMs, the maximum temperature drops considerably for both cases. The temperature differences between the two cases is found to be insignificant, with the observation that by adding fluid flow, the phases mixture is smoother. Moreover, by using fluid flow, the calculation time increases excessively due to the high non-linearity.

Commentary by Dr. Valentin Fuster
2014;():V003T12A003. doi:10.1115/ESDA2014-20054.

To enhance the cooling performance of a metal-foam heat sink, this work increases the surface area of the heat sink wall in contact with the electronic component by vertically placing a solid aluminum cylinder in the center (i.e., core) of an aluminum-foam heat sink. The contact ratio, defined as the ratio of the surface area of the extended heat sink wall in contact with the electronic component to the solid-fluid interface area inside the aluminum-foam heat sink, was systematically varied to experimentally investigate the heat transfer characteristics. The experimental results on the measured Nusselt number, solid-phase and gas-phase temperatures and temperature difference between the solid and gas of the aluminum foam under different contact ratios were reported and discussed in this work.

Commentary by Dr. Valentin Fuster
2014;():V003T12A004. doi:10.1115/ESDA2014-20063.

In this study, three-dimensional computational fluid dynamics (CFD) analyses are performed to assess the thermal-hydraulic characteristics of a commercial Gasketed Plate Heat Exchangers (GPHEx) with 30 degrees of chevron angle (Plate1). The results of CFD analyses are compared with a computer program (ETU HEX) previously developed based on experimental results.

Heat transfer plate is scanned using photogrammetric scan method to model GPHEx. CFD model is created as two separate flow zones, one for each of hot and cold domains with a virtual plate. Mass flow inlet and pressure outlet boundary conditions are applied. The working fluid is water. Temperature and pressure distributions are obtained for a Reynolds number range of 700–3400 and total temperature difference and pressure drop values are compared with ETU HEX. A new plate (Plate2) with corrugation pattern using smaller amplitude is designed and analyzed. The thermal properties are in good agreement with experimental data for the commercial plate. For the new plate, the decrease of the amplitude leads to a smaller enlargement factor which causes a low heat transfer rate while the pressure drop remains almost constant.

Commentary by Dr. Valentin Fuster
2014;():V003T12A005. doi:10.1115/ESDA2014-20065.

Heat advection by groundwater flow is known to improve the performance of ground heat exchangers (GHEs), but the effect of groundwater advection on performance is not yet fully understood. This study examined how parameters related to groundwater flow, such as aquifer thickness, porosity, lithology, and groundwater flow velocity, affect the performance of a borehole GHE. Under the thin-aquifer condition (10 m, or 10% of the entire GHE length in this study), groundwater flow velocity had the greatest effect on heat flux. With a groundwater flow velocity of at least 10−4 m/s through a low-porosity aquifer filled with gravel with high thermal conductivity, the heat flux of a GHE was as much as 60% higher than that of a non-aquifer GHE. If the aquifer is as thick as 50 m (50% of the entire GHE length), the high thermal conductivity of gravel doubled the heat flux of the GHE with a groundwater flow velocity of at least 10−5 m/s. Thus, not only groundwater flow velocity, but also aquifer thickness and thermal conductivity were important factors. However, groundwater seldom flows at such high velocities, and porosity, gravel size, and aquifer thickness vary regionally. Thus, in the design of ground source heat pump systems, it is not appropriate to assume a large groundwater effect.

Commentary by Dr. Valentin Fuster
2014;():V003T12A006. doi:10.1115/ESDA2014-20137.

In this paper, fully developed flow of a couple-stress fluid between two long vertical walls in presence of viscous dissipation and radiative heat flux with heat and mass transfer is considered. Temperature and concentration fields at one of the walls are oscillating around a non-zero value. The coupled equations governing the problem are discretized using Differential Quadrature Method, and solved using Newton-Raphson Method and Evolutionary Algorithm hybrid scheme. The expressions for velocity, temperature, and concentration fields for fully developed unsteady flow are obtained.

Commentary by Dr. Valentin Fuster
2014;():V003T12A007. doi:10.1115/ESDA2014-20146.

Compared to a conventional vapor compression refrigeration system, a magnetocaloric refrigerator has many advantages, such as potentially high efficiency, low vibration and avoidance of refrigerants that deplete the ozone layer and cause the greenhouse effect. As a main component of the active magnetic regenerative refrigerator, the regenerator plays an important role in the cooling performance and efficiency of the whole system. However, the regenerator design is constrained by several external factors, such as the geometry of the magnetic field source and flow resistance.

In this work, novel regenerators with complex flow arrangements, providing high performance at lower pressure drop, are investigated. Correspondingly a one dimensional model is presented and comparative studies between novel and conventional regenerators are carried out by simulation. The effect of regenerator geometries and different flow arrangements on the cooling performance, pressure drop and efficiency are investigated. In particular, the effect of so-called dead volume on the performance of a regenerator is researched.

Commentary by Dr. Valentin Fuster
2014;():V003T12A008. doi:10.1115/ESDA2014-20239.

Using a coarse time discretisation for saving calculation effort will induce non-uniform heat input within thermal-transient analyses which include translational rigid body motions by the technique of discrete displacement adjustment. We are going to show, why these non-uniformities are generally unavoidable and how a suitable choice of time step size pre-minimizes their consequences. Afterwards, the amount and location of the remaining load-bumps are analytical deduced for an arbitrary motion. With this information, we develop a correction method based on arithmetic calculations to avoid these numerical caused errors. For practical use, the correction is applied as an algorithm to the solution process of analyses with spatial discretized motion partners. We finish by demonstrating the performance of the correction.

Commentary by Dr. Valentin Fuster
2014;():V003T12A009. doi:10.1115/ESDA2014-20256.

Transient laminar free convection in a water-filled rectangular enclosure has been studied experimentally and numerically. The study aimed at gaining an insight into the physical phenomena, illustrated by the flow patterns and the temperature stratification, from the initial stage of a homogeneous fluid through the transient evolving process.

The experimental setup consisted of two rectangular water-filled enclosures: the smaller one contained a heat source and was centrally immersed in the larger one. Dye was injected for visualization of the rising boundary layer over the inner container walls, and the accumulation of the colored layers in the upper zone of the outer container. Simultaneously, the temperature measurements, by thermocouples and an infra-red camera, displayed the formation of a stratified structure.

The numerical study was conducted three-dimensionally, using the Fluent 6.3 software. The stratified temperature field, observed experimentally, was well-predicted by the numerical model.

The heat transfer rates and the transient averaged Nusselt numbers were compared with the data in the literature. The current, constant power input yielded Nu/Ra0.25∼0.7 in the range of Fo/Ra0.25 = 0–3.

Commentary by Dr. Valentin Fuster
2014;():V003T12A010. doi:10.1115/ESDA2014-20280.

In light of the potential of acoustic excitation for heat transfer enhancement, the research effort herein is geared towards a better understanding of the underlying physical mechanisms of aero-thermal laminar and turbulent boundary layer development under the influence of directed sound excitation. An experimental measurement campaign is carried out throughout which the effects of small amplitude periodic flow oscillations on convective heat transfer in straight channels are investigated. A low velocity wind tunnel facility has been designed and built for this purpose. Measurements of convective heat transfer are conducted by means of steady wide band liquid crystal thermometry at several acoustic and aerodynamic parameters. The findings of this investigation indicate that modification of convective heat transfer by directed sound excitations is possible. Dependent on the source frequency, the net effect can be a heat transfer augmentation or a local reduction. Although the acoustically induced changes are small in magnitude, the dependence on the excitation frequency is still quantifiable beyond measurement error.

Commentary by Dr. Valentin Fuster
2014;():V003T12A011. doi:10.1115/ESDA2014-20317.

The aim of this work is to compare the effectiveness of two induction heating methods of injection molds by means of thermovision measurement. The problem of selecting external or internal induction heating for thin-walled moldings used in electrical and electronic industry is taken into consideration. At first, the boundary conditions were defined. Then a group of three moldings with different defects were selected. The defects that have been taken to remove by means of induction heating are: weld lines, breaking hinges, air traps and diesel effect. In order to compare the methods of heating two models were created. The first one was made as a block of steel with milled grooves with a width of 2mm and a depth varying from 1 to 12mm. The second model consisted of two parts, one being placed in the second.

The research stand consisted of prepared models, induction generator with power of 10kW, specially shaped inductor, thermovision camera and temperature sensor of PT100 type as a reference. First, the surface with milled grooves was heated in four different sectors (because of the shape of inductor) in time of 2s. The area of low-depth grooves heated up to 154°C while the surface with 12 mm grooves heated up to 120°C. It comes from eddy currents flowing. This phenomenon shows that effectiveness of external heating of grooved surface decreases with increasing of grooves depth.

In the second case the cavity insert was heated as a coil inside the inductor which was located inside the mold. The measured value was the time of heat transfer from heated area to the forming surface in three configurations.

Commentary by Dr. Valentin Fuster
2014;():V003T12A012. doi:10.1115/ESDA2014-20412.

Fluctuations of electric load call for flexible generation technologies such as gas turbines. Alternatively, bulk energy storage (BES) facilities can store excess off-peak electricity to generate valuable peaking electricity. Interest in electricity storage has increased in the past decade in anticipation of higher penetration levels of intermittent renewable sources such as wind. Compressed Air Energy Storage (CAES) is one of the most promising BES technologies due to the large amount of energy (hundreds of MWh) that can be economically stored. CAES uses off-peak electricity to compress air into underground reservoirs. Air is combusted and expanded at a later time to regenerate electricity. One of the downsides of CAES is the large energy losses incurred in the form of waste compression heat. Distributed CAES (D-CAES) has been proposed in order to improve the roundtrip efficiency of CAES by utilizing the compression heat for space and water heating. The compressor of D-CAES is located near a heat load (e.g. a shopping mall) and the compression heat is recovered to meet this external load. D-CAES collects fuel credits equal to the negated heating fuel, leading to a higher overall efficiency compared to conventional CAES. We perform a thermodynamic analysis of conventional CAES and D-CAES to compare their heat rate, work ratio (electric energy stored per unit of electric energy regenerated), and exergy efficiency.

Commentary by Dr. Valentin Fuster
2014;():V003T12A013. doi:10.1115/ESDA2014-20418.

The classical Stefan problem proffers a suitable model for determining the temperature regimes as well as conjugate interfacial positions for multiphase problems. Obtaining the solutions to these problems exactly, especially in systems with cylindrical or spherical symmetry, is often an arduous task. This is largely due to inherent nonlinearities in the mathematical statements of Stefan problems.

In this paper, a tractable and effective approach is proposed. Subsequent to a recast as a system of differential-difference equations, and a methodical reduction to constant coefficient difference equations, exact similarity solutions are derived for a class of heterogeneous two-phase Stefan problems with cylindrical or spherical symmetry in one spatial dimension, under either Gaussian or hypergeometric perturbations.

Commentary by Dr. Valentin Fuster
2014;():V003T12A014. doi:10.1115/ESDA2014-20441.

During the year, due to weather conditions, the temperature fluctuations at surface level cause problems in underground pipes as a result of freezing water. One of the best prevention strategies is the use of polyurethane floor insulation for keeping the temperature of clay above zero degrees Celsius. In this study to calculate the minimum thickness of polyurethane insulation layer, the differential equation of energy is solved based on principle of separation of variables using imaginary eigenvalues for consistency with the temperature distribution in multi-layer consist of asphalt, gravel and polyurethane with finite thickness and clay as a semi-infinite medium with periodic thermal boundary conditions at surface level. Numerical approach is performed in Matlab and the results show that by using a thin layer of polyurethane it’s possible to greatly reduce the insertion depth of water pipes.

Commentary by Dr. Valentin Fuster
2014;():V003T12A015. doi:10.1115/ESDA2014-20483.

Evaporative condensers operate at lower temperatures and with a higher efficiency compared to air condensers, as heat rejection is limited by air wet bulb temperature and mainly caused by water vaporization. This reduces the compressor pressure-lift and improves refrigeration cycle performance.

Due to complex phenomena of heat and mass transfer on the tube bundles, modeling the evaporative condensers is a hard task and fine grids in numerical simulations are requested to reach acceptable results.

A two-dimensional steady state numerical model at the single tube scale has been developed in Ansys-Fluent (release- 14.5), adopting the VOF multiphase model.

Moist air has been treated as a mixture of air and water vapor species, while water vaporization and latent heat have been modeled with a C++ User Defined Function.

The tube wall temperature has been assumed constant.

The aim of this work is to describe the developed numerical model and to validate it by comparing results obtained at different operating conditions with empirical relationships found in the literature in terms of combined and overall heat transfer coefficients.

Combined heat transfer coefficient variation along the tube surface has been analyzed, observing that the heat transfer coefficient is higher in the impingement zone, becomes approximately uniform and rises approaching the trailing edge.

Moisture content distributions at different sections through the heat exchanger have been examined in detail as well.

This study will be the basis to investigate the performance of the whole condenser taking into account the real evolution of the operating conditions of each single tube in the bundle, whatever its arrangement.

Commentary by Dr. Valentin Fuster
2014;():V003T12A016. doi:10.1115/ESDA2014-20538.

A numerical analysis of mixed convection in a vertical channel filled with metal foam partially heated at uniform heat flux is studied numerically. Local thermal non-equilibrium and Brinkman-Forchheimer-extended Darcy model are assumed. Boussinesq approximation with constant thermophysical proprieties are considered. Results are carried out for an aluminium foam with 10 pore per inch (PPI) and ε=0.909, the fluid is air. Results, for different Reynolds numbers and geometrical aspect ratios, are given in terms of solid and fluid temperatures, at heated walls and inside the channel at several heights, velocity profile along the channel, local and average Nusselt numbers. Results show that diffusive effect resulted lower temperature values inside the solid and the fluid temperatures are higher in all considered cases. For heated channel with smaller aspect ratios, an average Nusselt number increase is found for solid and fluid phases.

Commentary by Dr. Valentin Fuster
2014;():V003T12A017. doi:10.1115/ESDA2014-20554.

In the present research, experimental data from several studies about drying behavior of mushrooms have been selected and used to compare different drying methods and different mathematical thin layer drying models to simulate mushroom drying rates. The white button (Agaricus Bisporus), the oyster (Pleurotus Ostreatus) and the milky mushroom slices have been considered for drying in different dryers such as hot air cabinet dryer and fluidized bed dryer with different slice thicknesses, drying air temperatures (45 °C to 90 °C) and drying air velocities (0.2 m/s to 5 m/s). The entire drying process has taken place in the falling rate period, assuming that internal mass transfer occurred by diffusion in mushroom slices. The study shows that the drying air temperature and the drying air velocity have an effect on the moisture removal from mushrooms and also on the drying time. Mathematical models have been proved to be useful for design and analysis of heat and mass transfer during drying processes. All the drying models considered in this study could adequately represent the thin layer drying behavior of mushrooms. Furthermore, as it is obvious, any type of mushrooms has its own most suitable model.

Topics: Drying
Commentary by Dr. Valentin Fuster
2014;():V003T12A018. doi:10.1115/ESDA2014-20594.

This paper handles numerical analyses that give attention to the relation between the thermal performance of concentric tube heat exchangers and its operational parameters. For this purpose, an iterative computational code is developed to compute thermal performance. The computations are based on supplying the code with the exchanger length, inner/outer diameters, inner/outer fluids, inner/outer flow rates and inner/outer inlet temperatures. A parametric analysis that examines the relation between the thermal performance of heat exchanger and inner/outer flow rates is presented. It is originated that the thermal performance and the overall heat transfer coefficient of a concentric tube heat exchanger increase through a rational function with the inner and outer flow rates.

Topics: Heat exchangers
Commentary by Dr. Valentin Fuster

Materials and Tribology

2014;():V003T14A001. doi:10.1115/ESDA2014-20090.

The objective of this work is to study the Rolling Contact Fatigue (RCF) behavior of hybrid bearings. The studied bearings are composed of Si3N4 balls rolling on steel raceways. The raceways are made out of nitrided 32CrMoV13 steel. The nitriding treatment aims at reinforcing the surface mechanical properties. As the presence of an indent on the raceway surface will dramatically decrease the fatigue life of the rolling element [1], this study focuses on the RCF behavior of pre-indented rolling element bearings.

It is thus necessary to study the fatigue behavior of both the steel and the ceramic material under fatigue loading. The study presented here focuses on the fatigue behavior of nitrided 32CrMoV13 steel under rolling contact and aims at proposing a crack initiation criterion based on experimental results.

Fatigue tests are performed on a bi-disks machine with indented 32CrMoV13 samples to observe the damage evolution and crack initiation stages under various indent dimensions and test conditions.

In parallel simulations are performed with a semi-analytical method to accurately determine the stress history under elastic-plastic rolling contact. Semi analytical methods, classically used for the simulation of elastic contacts, have recently been extended to the consideration of plasticity [2], allowing to simulate the ball-raceway interaction in ball bearings [3] and wear or running in [4]. The main advantage of these methods is their ability to simulate the coupling between the contact conditions and the plastic behavior in reasonable computational time.

Based on the experimental and simulation results, a crack initiation criterion based on the dislocation theory proposed by Tanaka and Mura [5] is proposed allowing to predict the number of cycles for crack initiation for the given material.

Commentary by Dr. Valentin Fuster
2014;():V003T14A002. doi:10.1115/ESDA2014-20107.

Many studies on the contact of tribo-surfaces with nanoscale roughness adopt simplified deterministic surface topographies, which lend themselves to analytical solutions for the contact forces. More elaborate approaches that use, for example, fractal formulations are inherently more difficult to analyze but are increasingly used in tribological research. In this paper, molecular dynamics is used to simulate the three-dimensional contact between atomically rough surfaces of fcc-Nickel. Two methods are used to generate the surface roughness: fractals and a statistical approach utilizing spherical asperities. The tribo-surfaces are compressed with normal pressure and the results are compared for each method of rough surface representation. The two methods yield very similar results for the case of isotropic, Gaussian roughness.

Commentary by Dr. Valentin Fuster
2014;():V003T14A003. doi:10.1115/ESDA2014-20121.

In most cases, scratching of the surface of a polymeric glass elicits brittle behavior and industrial solutions like coating have been successfully used to improve the scratch resistance. The origin of the success of the coating technique is still of great research interest since one of the limitations of this technique is the risk of cracking and chipping. In terms of interfacial adhesion characterization, a wide variety of methods have been used to assess this property of material systems. Nevertheless, the adhesion of coatings still remains to be successfully determined in a test which can reproduce the damage undergone by the coated surface during its real lifetime. In this context, scratch test constitutes a good candidate. The present study deals with the scratching technique as an interfacial adhesion measurement in coated systems.

Using a single-asperity scratching device allowing in-situ observation of the scratch, the fracture of a thin nano-composite coating deposited on its substrate was investigated under different conditions of temperature and scratching speed. Four types of fracture kinetics were observed depending on these two variables. One of these exhibits a stable blister growth at the same speed as the movement of the indenter over hundreds micrometers. This slow and extensive growth of a blister was obtained at 80 °C at a scratching speed of 10 μm/s. When the blister has reached a certain size, it propagates with the indenter without increasing further in size: it constitutes the steady state blister growth.

A variational form of the energy balance of a blistering process is proposed, which permits to assess the adhesion of the system. Actually, the energy spent in the delamination process can be determined by following the delaminated area during the blistering process with regard to the scratching distance. The main difficulty is to estimate the energy dissipated in plastic flow. Different tests were conducted with various indenters: spheres with different radius and roughness. Thanks to this multi-criterion approach, it was possible to fit a unique value of the adhesion in the case of experimental stable blistering growths. The results are discussed with regard to reliability and probe characteristics.

Topics: Adhesion
Commentary by Dr. Valentin Fuster
2014;():V003T14A004. doi:10.1115/ESDA2014-20125.

The basics of antifriction coatings is to lower the frictional response of a surface. The coated material should either lower the interfacial shearing or increase stiffness of the surface. The latter should be reached by using carbon nano-fillers embedded in a polymer matrix. We choose PMMA as a matrix. The objective of this study is to gain knowledge on the influence of carbon nano-fillers on the surface response of PMMA nano-composites.

Commentary by Dr. Valentin Fuster
2014;():V003T14A005. doi:10.1115/ESDA2014-20194.

The paper proposes a brief overview of the commonly adopted approaches for the experimental study of scuffing on gears for advanced applications and suggests a new methodology for the design of an experimental campaign aimed at determining the scuffing resistance of an innovative aerospace gear material.

The present study has been carried out by AM Testing srl in collaboration with Avio Aero within the VHLGM (Validation of High Load Capacity Gear Material) project of the Clean Sky Sustainable and Green Engines framework.

Topics: Gears
Commentary by Dr. Valentin Fuster
2014;():V003T14A006. doi:10.1115/ESDA2014-20204.

The friction induced in contacts is a key feature concerning functionality of mechanisms, reliability of systems, energy consumption… Friction on soft matter occurs in many applications (tire/road contacts, touch-sensitive exploration, micro-manipulation of biological items…) as well as in nature. The latter offers various examples of how a topographic surface pattern may control friction. The result is a complex combination of phenomena: adhesion, elastic ratio of bodies in contact, viscous flow, plasticity occurrence, and topography interaction. The role of this latter phenomenon essentially lies in the splitting of the contact area between the two contacting materials and plays an important role on friction response when coupled with adhesion.

Commentary by Dr. Valentin Fuster
2014;():V003T14A007. doi:10.1115/ESDA2014-20231.

The mechanical properties and wear behavior of Dual Phase (DP) steels have been investigated and compared with those observed in normalized (N) steel that has the same chemical composition. The DP steels having different content and morphology of martensite were produced by varying intercritical annealing temperature and initial microstructures. Mechanical properties of four different DP steels and N steel have been investigated by carrying out tensile and macrohardness tests. Dry sliding wear tests have been conducted on four different the DP steels and the N steel using pin-on-plate to investigate their wear characteristics. It has been found that the yield and tensile strengths and macrohardness increase with increasing martensite content and decreasing martensite size. The yield and tensile strengths and macrohardness of the N steel were significantly lower than the DP steels whereas percentage of total elongation was higher. Wear properties are improved by increasing martensite volume fraction and size in the DP steels. The N steel specimen showed the highest wear rate.

Commentary by Dr. Valentin Fuster
2014;():V003T14A008. doi:10.1115/ESDA2014-20264.

Blade-disk contact within high pressure compressor, is a high temperature fretting contact zone submitted to high stress levels. Therefore, it is important to estimate the various damages encountered in this area in order to correctly predict the lifetime of the parts. Coatings are used in order to improve the strength of the parts. In the framework of Innolub project, this study aims at developing a numerical model of coated contact accounting for wear and temperature. The objective is to estimate the kinetics of wear, to simulate worn surfaces and to allow the manufacturer to produce analyses of design with worn surfaces using a fast, efficient and reliable method of calculation.

Topics: Wear
Commentary by Dr. Valentin Fuster
2014;():V003T14A009. doi:10.1115/ESDA2014-20379.

In recent years, the development of high-strength steels such as multi-phase TRIP (transformation-induced plasticity)-aided steels have shown great promise due to their excellent combination of high strength and ductility. In this paper, the effect of strain-induced martensitic transformation on mechanical properties is studied. Uniaxiale tension tests at different strain rate (10, 15 and 20 mm / min) are conducted at 25° C in order to characterize the mechanical behavior of AISI 304L. The microstructure, particularly retained austenite, is analyzed using optical microscopy, Vickers hardness measurements. The results showed that all properties measured are increased from (Re=390.96MPa to Re=425.96MPa and Hv=300.94Hv to 343.51HV).

Secondly, the influence of the annealing treatment on microstructure and mechanical properties of the joint formed by the spot welding are characterized using tensile test, metallographic analysis and Vickers hardness measurements.

Commentary by Dr. Valentin Fuster
2014;():V003T14A010. doi:10.1115/ESDA2014-20388.

Heavily loaded point EHL contacts involved in steady purely transitional, skewed transitional, and transitional with spinning motions are considered. It is shown that in the central parts of the inlet and exit zones of such heavily loaded point EHL contacts the asymptotic equations governing the EHL problem along the lubricant flow streamlines for the above types of contact motions can be reduced to two sets of asymptotic equations: one in the inlet and one the exit zones. The latter sets of equations are identical to the asymptotic equations describing lubrication process in the inlet and exit zones of the corresponding heavily loaded line EHL contact [1]. For each specific motion of a point contact a separate set of formulas for the lubrication film thickness is obtained. For different types of contact motions these film thickness formulas differ significantly [1]. For heavily loaded contacts the discovered relationship between point and line EHL problems allow to apply to point contacts most of the results obtained for line contacts [1,2].

Commentary by Dr. Valentin Fuster
2014;():V003T14A011. doi:10.1115/ESDA2014-20396.

Rolling contacts are a major topic in scientific studies as they are highly exposed to fatigue damage. Indeed, the applied loads generate periodic stresses and the surface roughness generates stress concentrations close to the surface. The combination of these two phenomena facilitates fatigue damage. Many multi-axial criteria have been created to explain and predict this type of damage. Furthermore, a large number of papers compare the different fatigue criteria based on combined bending and torsion tests [1,2]. However, these studies are not representative of the stress gradients found in rough contacts, close to the surface. Hence the current work, which proposes a comparative study of several fatigue criteria with a combined experimental and numerical approach.

Commentary by Dr. Valentin Fuster
2014;():V003T14A012. doi:10.1115/ESDA2014-20442.

At the start of welding activities in oil and gas projects, high welding rejection rates (WRR) are often reported. This is a cause for concern to companies because welding defects that are not identified nor corrected can have serious consequences, such as on asset integrity, cost of rework, and schedule impact. Therefore, the quality organizations immediately investigate the different causes and recommend solutions which eventually contributes toward lowering the WRR.

Based on recent field studies conducted in oil and gas projects using the Six Sigma methodology, high WRRs are caused by many factors, including but not limited to the following:

1. New and inexperienced welders with poor welding techniques.

2. Poor environments surrounding the welding activities.

3. Discrepancies and inaccurate data in the welding tracking system (WTS).

These contributing factors can be reduced and eliminated by implementing a strong welding inspection and control program with the following recommendations:

1. Screen for qualified and experienced welders with a proven successful welding history before starting the welding.

2. Test the welders on-site before actual production welding.

3. Implement an encouragement scheme for welders by having frequent toolbox meetings and presenting awards for the best welders according to the lowest rejection rates.

4. Assess the WTS constantly to prevent any inaccurate data.

Commentary by Dr. Valentin Fuster
2014;():V003T14A013. doi:10.1115/ESDA2014-20506.

The objectives in this paper are to investigate the effects of the filler content and size on the effective thermal conductivity of the PE/Al; PE/Cu, PE/Fe and PE/bronze composites. The polymer matrix of the polymer/metal composites was two types of polyethylenes: LDPE and HDPE (from Basell Orlen). The following polymer/metal composites obtained by extrusion process containing: 10% by weight of Al, Cu, Fe and bronze powder in LDPE matrix and composites containing 5, 10, 15 and 20% by weight of Al flakes in HDPE polymer were prepared and tested. Adding in the extrusion process 10% by weight of bronze powder into the polyethylene, increased more than five times the thermal diffusivity of produced composite. Use as a filler 20% wt. of aluminum flake increases it by more than twice. The study showed the ability to produce polyethylene matrix composites with the addition of metal powder fillers (Al, Cu, Fe, and bronze). Analyzing the measuring results of thermal diffusivity coefficient by Angstrom method, it can be concluded that with the appropriate filler content, the particles are located close enough to each other to form a continuous conductive path, then the thermal diffusivity of the composite increases significantly.

Commentary by Dr. Valentin Fuster
2014;():V003T14A014. doi:10.1115/ESDA2014-20539.

The small wind energy produces electric energy using power turbines below 100 kW. This technology allows the electrical supply in places isolated, generates energy of way distributed (distributed microgeneration) and permits to produce electricity in the points of consumption. The rotomoulding process is characterized to allow hollow plastics parts, with great surface quality, good homogeneity of thicknesses and suitable mechanical properties, all this with a great freedom of design and a wide variety of materials. The Department of Economy and Competitiveness from Government of Spain, inside the Subprogram INNPACTO 2012, resolved to grant the project of title Development of new blades made for rotational moulding for small wind generators (RotEos). The main purpose of this project is focused on getting a viable and cheaper process to manufacture the blades to small wind generators without reducing the efficiency of them, and trying to increase the competitiveness of these turbines. This research work presents the initial results obtained in the design of the blades, materials characterization and in the manufacturing process of these components.

Commentary by Dr. Valentin Fuster
2014;():V003T14A015. doi:10.1115/ESDA2014-20546.

One of the challenges that impede the use of the relatively new friction stir welding (FSW) process in joining steels and high temperature alloys, as well as dissimilar materials, is the development of the right pin tool material that can stand the severe welding conditions of these alloys. Recent developments in FSW tool materials include tungsten rhenium (W-Re) alloys. The ductile to brittle transition temperature of pure tungsten is reduced by the addition of rhenium (Re).. The addition of Re also improve fracture toughness of the alloy. The major focus of this paper is studying the process of making a friction stir welding bead on mild steel using a proprietary W-25%Re alloy pin tool and investigating the effects of process parameters (i.e. tool rotational and welding speeds) on microstructure, microhardness as well as tool reaction loads. Grain refining of the steel microstructure was observed in all beads. Certain process conditions produced a bead with needle like microstructure with the highest values of hardness. Reaction forces were found to increase with the increase in the tool welding speed and to decrease with the increase of the tool rotational speed. Although the spectroscopic analysis of the beads confirmed the diffusion wear of the tool, the overall tool has shown excellent resistance to mechanical wear.

Topics: Friction , Steel
Commentary by Dr. Valentin Fuster
2014;():V003T14A016. doi:10.1115/ESDA2014-20623.

In plastic injection molding the most critical component in terms of wear and corrosion problem is represented by the barrel-screw system. This is due to the friction of plastic on the inner part of the barrel and to contact between the screw and the inner walls of the barrel. Fiber laser cladding is a promising technique that, through deposition of powder onto a substrate increases wearproprieties and consequently lifetime of the component. In particular, cladding Ni-Cr alloy with WC is an extremely promising combination of elements for this purpose. Specifically, WC is able to increase the hardness of the deposit so that it becomes more suitable for severe wear application. On the other hand, high Cr amount contained in the Ni-based alloy, guaranties high corrosion resistance for harsh environments. Nevertheless, this combination of materials is highly susceptible to cracks. Through the optimization of process parameters and preheating temperature (250-350-450-550°C) defect free coatingsare obtained. This work presentsan investigation on fiber laser cladding of Ni based alloy (Ni40, Ni60) with addition of spherical tungsten carbides (-53+20 μm) on C60 steel substrate. Optimal conditions are evaluated through macro and a micro analysis. In the first case penetrantliquids are used to evaluate crack presence. For the second field, micro hardness was measured and microstructure if cross-sectioned samples were investigated by optical microscopy.

Commentary by Dr. Valentin Fuster
2014;():V003T14A017. doi:10.1115/ESDA2014-20632.

This paper describes the measurement of oil film thickness between rolling element and inner raceway in cylindrical roller bearing. A fine piezoelectric element is bonded on the inner surface of the inner ring to measure the reflection coefficient of oil between rolling element and inner raceway. The quasi-static spring model is used to calculate oil film thickness from the corrected reflection coefficient data. Experiments are described on a simplified cylindrical roller bearing configured by one cylindrical roller, 11ø, and an inner ring from a NU209EM bearing. Reasonable agreement is shown over several loads and speeds with predictions from elastohydrodynamic lubrication (EHL) theory.

Commentary by Dr. Valentin Fuster

Mechatronics

2014;():V003T15A001. doi:10.1115/ESDA2014-20032.

Vibration of electrodes in Electric Arc Furnace (EAF) fed by AC current for steel melting is usually fairly large. It might be dangerous for the EAF operation and often reduces the efficiency of melting process. Vibration amplitude depends on the vertical position control operated to keep the arc length constant as much as possible and to the electromechanical actions due to the mutual magnetic induction among the three electric phases. Since designer of the EAF system needs a clear correlation between each design parameter and the dynamics observed a first modeling activity was performed. A mechatronic approach was implemented, by including the electromechanical coupling into the structural analysis performed to predict the system dynamics. A Multi Body Dynamics (MBD) code was used in cooperation with the Finite Element Method (FEM). A preliminary experimental validation on a real plant was tentatively performed.

Commentary by Dr. Valentin Fuster
2014;():V003T15A002. doi:10.1115/ESDA2014-20102.

This paper presents the results of a comparative study that investigated the use of image-based and signal-based sensors for fault detection and fault isolation of visually-cued faults on an automated assembly machine. The machine assembles 8 mm circular parts, from a bulk-supply, onto continuously moving carriers at a rate of over 100 assemblies per minute. Common faults on the machine include part jams and ejected parts that occur at different locations on the machine. Two sensor systems are installed on the machine for detecting and isolating these faults: an image-based system consisting of a single camera and a signal-based sensor system consisting of multiple greyscale sensors and limit switches. The requirements and performance of both systems are compared for detecting six faults on the assembly machine. It is found that both methods are able to effectively detect the faults but they differ greatly in terms of cost, ease of implementation, detection time and fault isolation capability. The conventional signal-based sensors are low in cost, simple to implement and require little computing power, but the installation is intrusive to the machine and readings from multiple sensors are required for faster fault detection and isolation. The more sophisticated image-based system requires an expensive, high-resolution, high-speed camera and significantly more processing power to detect the same faults; however, the system is not intrusive to the machine, fault isolation becomes a simpler problem with video data, and the single camera is able to detect multiple faults in its field of view.

Commentary by Dr. Valentin Fuster
2014;():V003T15A003. doi:10.1115/ESDA2014-20106.

This paper investigates the kinematical behavior of a polymer based star-shaped actuator, able to produce mechanical work through the shape memory effect, that allows a significant shape variations on the application of an external stimulus. The adopted material is a semicrystalline network based on poly(ε-caprolactone) crosslinked by thermal curing; the material was adopted due to its fast recovery process when heated close to the melting temperature and the high recovery degree, and, due to its good biocompatibility, it may suitable for biomedical application. The original, or “permanent”, material shape is that of a cylindrical annulus, which is set in a “temporary” configuration as a six spikes star. The temporary shape is fixed through a thermo-mechanical program, involving deformation above melting temperature and cooling under fixed strain and carried out by means of an ad-hoc designed fixture. By heating the deformed specimen above the melting temperature, the system is able to recover the original cylindrical shape realizing a motion and a mechanical power. This peculiar response, consisting in a progressive radial expansion activated by temperature, may be considered for application as self-expanding stenting device triggered by the human body temperature.

The shape of the system, that changes during the transformation, can be described as a two dimensional temporal function that represents the mean line of the section of the cylindrical annulus (perpendicular to the height of the annulus). This temporal function is a combination of a circular function and of a modified rhodoneal function and, after a proper calibration through experimental tests, is used to evaluate the kinematics of the system. The function is able to describe adequately the shape evolution experimentally displayed by the samples, with a very good agreement at the starting and final instants of the transformation, while the accuracy during the transformation is acceptable for the proposed application.

Commentary by Dr. Valentin Fuster
2014;():V003T15A004. doi:10.1115/ESDA2014-20114.

Using rather well known theory about capillary bridges between two electrodes we calculate the tensile force that can be applied to liquid metal contacts in the micrometer regime. Assuming circular symmetry, full wetting of the electrodes, and neglecting gravity, we present a brief review of the necessary theory and find numerically the forces to be in the 100μN range for liquid metals as mercury and liquid Gallium suspended between electrodes of 20μm radius.

Topics: Liquid metals
Commentary by Dr. Valentin Fuster
2014;():V003T15A005. doi:10.1115/ESDA2014-20126.

As mobile robots experience increased commercialization, development of intuitive interfaces for human-robot interaction gains paramount importance to promote pervasive adoption of such robots in society. Although smart devices may be useful to operate robots, prior research has not fully investigated the appropriateness of various interaction elements (e.g., touch, gestures, sensors, etc.) to render an effective human-robot interface. This paper provides overviews of a mobile manipulator and a tablet-based application to operate the mobile manipulator. In particular, a mobile manipulator is designed to navigate an obstacle course and to pick and place objects around the course, all under the control of a human operator who uses a tablet-based application. The tablet application provides the user live videos that are captured and streamed by a camera onboard the robot and an overhead camera. In addition, to remotely operate the mobile manipulator, the tablet application provides the user a menu of four interface element options, including, virtual buttons, virtual joysticks, touchscreen gesture, and tilting the device. To evaluate the intuitiveness of the four interface elements for operating the mobile manipulator, a user study is conducted in which participants’ performance is monitored as they operate the mobile manipulator using the designed interfaces. The analysis of the user study shows that the tablet-based application allows even non-experienced users to operate the mobile manipulator without the need for extensive training.

Topics: Manipulators
Commentary by Dr. Valentin Fuster
2014;():V003T15A006. doi:10.1115/ESDA2014-20128.

This paper describes the development of a wearable interface that exploits the user’s natural arm movements to intuitively control a robotic manipulator. The design is intended to alleviate the time and effort spent in operating the robotic manipulator, regardless of the age and technological experience of the user. The interface is made to be low-cost, comfortably worn, and easy to put on and remove. Kinematic models of human and robot arms are used to produce a natural mapping from the user’s arm movements to the commanded movements of the robotic manipulator. An experiment is conducted with 30 participants of varied ages and experience to assess the usability of the wearable interface. Each of the participants is assigned to perform a pick and place task using two of three different interfaces (the wearable interface, a game controller, and a mobile interface running on a tablet computer) for a total of 60 trials. The results of the study show that the wearable interface is easier to learn compared to the alternative interfaces and is chosen as the preferred interface by the participants. Performance data shows that the users complete the pick and place task faster with the wearable interface than with the alternative interfaces.

Topics: Manipulators
Commentary by Dr. Valentin Fuster
2014;():V003T15A007. doi:10.1115/ESDA2014-20133.

User interfaces that incorporate intuitive interaction metaphors have the potential to make remote control of physical systems feel more natural than ever before. The spread of smart mobile devices, such as smartphones and tablets, provides opportunities to develop and examine examples of such interfaces due to the devices’ portability and the intuitiveness and reprogrammability of mobile applications. However, the design of metaphors for interacting with a particular system poses an open-ended, creative design challenge that lacks a single-point solution. This paper explores what we refer to as a dominant metaphor for performing a teleoperation task via interaction with a mobile user interface. These dominant metaphors may be inspired from the physical nature of the system to give the user the most natural experience when using a mobile interface. Our approach for choosing an appropriate metaphor of interaction is demonstrated with an experiment wherein participants are asked to use different interaction metaphors to control a ball and beam testbed. Experimental data shows that the preferred metaphor of the participants is the dominant metaphor of interaction, the one which yields significantly better task performance.

Commentary by Dr. Valentin Fuster
2014;():V003T15A008. doi:10.1115/ESDA2014-20138.

In Denmark the public water supply is practically 100% served by groundwater abstracted from nearly 20.000 water wells. During time of operation the productivity from a well will often decrease drastically. This impaired performance is usually caused by well clogging. This clogging makes the well economically inefficient for the operator and therefore needs to be rehabilitated. This article examines the performance and evaluates the effectiveness of high power ultrasonics for water well rehabilitation. Special focus is drawn to the inconsistent efficiency of the currently, rarely used ultrasonic cleaning method caused by the specific varying conditions in water wells and correlated ultrasound intensity losses. The scope for improving the, in Denmark, rarely used ultrasonic cleaning method efficiency is investigated and suggestions for improvements based on a proof-of-concept prototype are given based on empirical- as well as theoretical studies.

Commentary by Dr. Valentin Fuster
2014;():V003T15A009. doi:10.1115/ESDA2014-20172.

The work deals with the design of an active smart damper based on a proof-mass actuator to suppress vibration in structures. The device is stand-alone and does not requires any additional real-time board to perform the control or sensors to obtain feedback signals as it mounts on board all the electronics needed to carried out this task.

Commentary by Dr. Valentin Fuster
2014;():V003T15A010. doi:10.1115/ESDA2014-20175.

The paper deals with a project aimed to improve the reliability of a condition monitoring system applied on gearboxes installed on rolling mills. In this context, to properly set up the algorithm, it is necessary to have measurements associated both to standard operating conditions and to malfunctioning. The latter, not being able to be experimentally generated, can be simulated by developing numerical models of the machine under varying conditions. The outputs generated, corresponding to different fault conditions associated with the main common failures of the elements that constitute the transmission, will provide a useful data base to tune the algorithm of condition monitoring.

Commentary by Dr. Valentin Fuster
2014;():V003T15A011. doi:10.1115/ESDA2014-20189.

This work focuses on the development of a methodology for the complete reconstruction of the 3D geometry of a concrete bridge. 3D scanning technology was selected as the most apt to the task as it provides very detailed geometrical informations. A dedicated carriage system for a compact and lightweight laser scanner has been designed and built as a first prototype to be used on laboratory as well as future on-field tests. A first assessment of the design constraints has been carried out, based on the general goal of implementing a system able to be used with existing inspection vehicles with minimal modifications. The specific electronic system for management and control of the carriage system and the management of the associated tracking system has been also designed and realized. Some preliminary tests have been performed at Politecnico di Milano University campus to assess the viability and analyze the performance of the early design choices.

Commentary by Dr. Valentin Fuster
2014;():V003T15A012. doi:10.1115/ESDA2014-20192.

Concrete bridge inspection is nowadays primarily a slow, subjective, non-comprehensive and costly set of procedures. Automation of the acquisition method is especially desirable for economical and repeatability reasons. Digital data is normally derived from well established non-destructive testing techniques, high resolution cameras and, more recently, by 3D laser scanning. This latter technique has some advantageous aspects in terms of reliability, repeatability, completeness and intuitiveness of the analysis of the resulting 3D reconstruction of the concrete structure. Statical laser scanning is, though, impractical for a variety of different reasons. A possible way of overcoming such difficulties is represented by dynamical measurement, achieved by moving in a prescribed manner the laser scanner during the scanning process. This procedure, on the other hand, requires a reliable tracking system for the laser scanner position and orientation. This work focuses on the development of such system, based primarily on computer vision measurement systems. A compact and lightweight 3D laser scanner has been placed on an automated carrier able to move along a standard inspection by-bridge, and a system of cameras and transducers has been designed to measure the carrier position and orientation based on the assumption of rigid body motion of the by-bridge multi-link arm during inspection operations. Several experimental tests have been performed to assess the viability of the proposed system and to evaluate its performance.

Commentary by Dr. Valentin Fuster
2014;():V003T15A013. doi:10.1115/ESDA2014-20263.

Conventional pneumatic systems present several advantages over competitive technologies, as they do not exhibit significant heat or magnetic fields and present high force to volume ratios. Nevertheless, they are very difficult to control due to their inherent nonlinearities like friction forces or air compressibility. As a consequence, their use is limited to simple motion tasks. This paper uses a nonlinear control law, previously developed by the authors, to control a servopneumatic system in the micro meter range. Preliminary experimental results show that the control law leads to very accurate motion control in micro meter positioning tasks in any position of the piston stroke. The paper also shows, through experimental results, that the control law is robust to parametric variations (change of payloads) and to external constant disturbances (gravity force).

Topics: Motion control
Commentary by Dr. Valentin Fuster
2014;():V003T15A014. doi:10.1115/ESDA2014-20328.

The paper deals with a new concept hydraulic spool valve. The new patented valve presents a secondary rotary type actuator connected to a sleeve interposed between the spool and the valve body, thus composing a roto-translating valve. The sleeve presents holes that can be moved and positioned partially or totally overlapped to the valve ports, thus allowing a secondary metering, that can be controlled according to the spool position. The valve port area is then related to the movement of the spool, and to the rotary movement of the cylinder, controlled by a different type of motors. The valve port area is the result of two actuators position, and the resulting control is linearly depending by two PWM signals, both controlled by a microcontroller based unit. Due to the valve structure, the metering control precision is virtually quadratic in respect to the traditional valve spool position electronic control, due to the concurrency of two electronically controlled actuators. Similar considerations could be done for the valve speed, due to the concurrent speed of two different actuators. Another big advantage is the lack of need of special spool design for different applications, due to the possibility offered by the two actuators control. The valve can realize both basic logic functions (AND, OR), and advanced control techniques; moreover in term of safety it offers a fail operational characteristic, in reason of an operational redundancy and functional diversity.

Topics: Safety , Valves
Commentary by Dr. Valentin Fuster
2014;():V003T15A015. doi:10.1115/ESDA2014-20414.

Mechatronic systems are a combination of cooperative mechanical, electronics and control components. The high number of their components, their multi-physical aspect, the couplings between the different domains involved and the interacting design objectives makes the design task very tedious ad complex. Due to this inherent complexity, a concurrent systematic and multi-objective design thinking methodology is crucial to replace the often used sequential design approach that tends to deal with the different domains separately. In this research we present a new multi-criteria profile for mechatronic system performance evaluation in conceptual design stage. The newly introduced Mechatronic Multi-criteria Profile (MMP) includes various quantitative members such as intelligence, reliability, complexity, flexibility and cost. A nonlinear fuzzy integral called 2-additive Choquet Integral will be used for the aggregation of criteria and fitting the intuitive requirements for decision-making in the presence of interacting criteria. Finally, the effectiveness of the proposed method will be validated via a case study of designing a robotic visual servoing system.

Commentary by Dr. Valentin Fuster
2014;():V003T15A016. doi:10.1115/ESDA2014-20434.

This paper presents a monolithic bistable micro-actuator with stroke reducing structure. A single pre-shaped beam was chosen as the bistable element. To constraint the rotation of the central point of the beam and get more precise output, two kinds of stroke reducing structures were designed and monolithically integrated into the actuator. The first design is purely based on flexible hinges. To decrease the dimension of the stroke reducing structure and maintain the output at the same order, a second hybrid stroke reducing structure integrated micro-actuator using flexible hinges and deflected beams was designed. Both devices were fabricated by laser machining of medium density fiberboard material. Outputs of the bistable micro-actuator before and after the reducing structure were measured by fiber optic distance sensor. The bistability was experimentally characterized. The output stroke before and after reduction for the first reducing structure are 2.38mm and 0.79μm. The outputs stroke before and after reduction for the second hybrid reducing structure are 2.38mm and 0.99μm.

Topics: Microactuators
Commentary by Dr. Valentin Fuster
2014;():V003T15A017. doi:10.1115/ESDA2014-20469.

Accurate ballscrews are vital components of precise machine tool drive systems. As determined by direct measurement systems, the ballscrew positioning error has no bearing on the final positioning accuracy of the axis. For economical reasons, however, most machine tools are equipped with indirect measurement systems, in which errors stemming from thermal expansion of the ballscrew constitute approximately 60% of the kinematic chain error sum. Moreover, the currently observed boost in productivity of modern CNC machine tools leads to significant amplification of energy dispersal values in the nut-screw systems, due to the increased positioning velocity of the controlled axes. This, in turn, contributes to a rise of positioning error values through thermal expansion of the aforementioned ballscrews. This article deals with technological and constructional problems of screw lengthening compensation. It enumerates methods of thermal expansion-based error compensation as attained through utilization of indirect measurement systems. Finally, it presents experimental data indicating the possibility of effective screw lengthening compensation, thus proposing an alternative to the currently applied compensation systems.

Commentary by Dr. Valentin Fuster
2014;():V003T15A018. doi:10.1115/ESDA2014-20470.

This paper discusses the application of second order mode controls to hydraulic valve-cylinder drives with a special focus on the limitations resulting from nonlinear dynamic effects in flow control valves. Second order sliding mode algorithms appear highly attractive in the successive implementation of sliding mode control, achieving continuous control inputs, while maintaining the main properties of sliding modes. Under certain model assumptions, some of these controllers may even be applied as output feedback controllers. However, intrinsic nonlinear dynamic effects of hydraulic valves such as slew rates and time delays arising in the amplification stages, limits the applicability of such methods, and may lead to partial losses of robustness and limit cycles. These properties are analyzed and experimentally verified, and compensation methods are proposed. The application of the second order sliding algorithm known as the super twisting controller is considered for output feedback control and compared with conventional first order sliding mode control. The controllers under consideration are applied for position tracking control of a hydraulic valve-cylinder drive exhibiting strong variations in inertia- and gravitational loads. Results demonstrate that the super twisting algorithm may be successfully applied for output feedback control of hydraulic valve-cylinder drives, with modifications guaranteeing robust control performance in a small vicinity of the control target.

Commentary by Dr. Valentin Fuster
2014;():V003T15A019. doi:10.1115/ESDA2014-20495.

The focus of this paper is on the development of a high-fidelity electro-mechanical Control Loading System (CLS) for a rotary wing aircraft simulator. CLS is one of the major components of a flight simulator. It is used for providing realistic force feedback to pilots. The pilot in a real aircraft feels the forces acting on control surfaces through cockpit controls. During simulation, these forces are produced by CLS actuators. For this reason, CLS must behave exactly like the aircraft control hardware, statically and dynamically. The fidelity of the force feel simulation is a key criterion for flight simulation certification. It is also important that a CLS design is reconfigurable and modular such that it conforms easily to different simulator models and simulations of different aircrafts. The work also includes system integration of a research simulator for testing purposes. Design and selection of hardware and software components of the CLS and the simulator are presented along with the overall system architecture.

Topics: Aircraft , Wings
Commentary by Dr. Valentin Fuster
2014;():V003T15A020. doi:10.1115/ESDA2014-20583.

Sensor nodes are innovative devices that can perform measurements on a large scale and communicate over a network. One of the most significant problems regarding the sensor nodes is how to supply power to a large number of devices. For this reason, they greatly benefit from energy harvesting techniques which can provide energy recovered directly from the environment. A study of the design and the modeling of an autonomous sensor node, powered by a vibrational piezoelectric harvester, is reported here. Subject of the first part of the analysis is a piezoelectric bimorph: an analytical model is proposed in order to estimate the performance, giving particular attention to the optimal mechanical and electrical parameters. The model is then validated through experimental tests, assuming different kinds of real scenarios. Then the results are used to design a device that can benefit from this harvester. In particular a wireless sensor node is developed, for which the energy scavenging ensures energy autonomy and long-term operability. Thanks to a particular harvesting circuit and opportune algorithms for energy management, this system is able to extract energy from vibrations and store it into capacitors. The embedded accelerometer and a wireless module make this device ideal for Structure Health Monitoring purposes.

Commentary by Dr. Valentin Fuster
2014;():V003T15A021. doi:10.1115/ESDA2014-20191.

In this work, it is considered a 6-DoF robotic device intended to be applied for hardware-in-the-loop (HIL) motion simulation with wind tunnel models. The requirements have led to a 6-PUS parallel robot whose linkages consist of six closed-loop kinematic chains, connecting the fixed base to the mobile platform with the same sequence of joints: actuated Prism (P), Universal (U), and Spherical (S).

As is common for parallel kinematic manipulators (PKMs), the actual performances of the robot depend greatly on its dimensions. Therefore, a kinematic synthesis has been performed and several Pareto-optimal solutions have been obtained through a multi-objective optimization of the machine geometric parameters, using a genetic algorithm.

In this paper, the inverse dynamic analysis of the robot is presented. Then, the results are used for the mechanical sizing of the drive system, comparing belt- to screw-driven units and selecting the motor-reducer groups. Finally, the best compromise Pareto-optimal solution is definitely chosen.

Topics: Robotics
Commentary by Dr. Valentin Fuster

Robotics

2014;():V003T17A001. doi:10.1115/ESDA2014-20076.

This work deals on a kinematical model of a parallel mechanism for biomedical applications. The mechanism is a linkage composed by three closed loops. It is composed by seven bars (one of them is the frame) constrained each other by ideal constraints (prismatic, rotary or lock joints). The ideal joints introduce 21 degrees of constraint, while the bars produce eighteen degrees of freedom when considered rigid. Six bars are really rigid, while one of them is compliant with respect to the others and allows the mobility of the mechanism. The kinematic of this seven-bar linkage is analyzed with the aim of Hermite’s polynomials. The proposed approach is based on the knowledge of kinematical constraints at the ends of the compliant beam, in terms of position and curvature. This knowledge is based on the fact that the rest of the structure is composed by rigid bodies and ideal concentrated constraints. The compliance affects the beam only with bending effects, furthermore, in this work, we consider only a planar linkage, thus the torsion effect is not considered, and the beam is constrained in ways that compression instability is negligible. Although the beam is subjected to important deformations, it is divided in parts, such that each part is subjected to a small deformation. In this way, we propose the Hermite’s polynomials to describe the shape of the beam. We tested this fast method to describe the kinematical behavior of the system with a kinetostatic model of a mechanical device, finding that it is reliable for the proposed application.

Topics: Kinematics , Linkages
Commentary by Dr. Valentin Fuster
2014;():V003T17A002. doi:10.1115/ESDA2014-20094.

This work deals with the design of parallel robots for the generation of pick-and-place operation, or Schönflies motion. The aim is to develop a robot with workspace optimized for fast pick-and-place operations, namely, a robot with a superellipsoidal reachable volume, which suits best for the pick-and-place operations on conveyers, where robots’ working areas are nearly rectangular.

In this paper, the kinematics and stiffness modeling of the new robot are presented. A method of stiffness modeling by means of Castigliano’s Theorem is developed. Using the new method, the stiffness of the robot is analyzed. The results are compared with FEA simulation, which shows a good agreement between the results. The method is finally applied to the engineering design of the new robot for enhanced static and dynamic performance.

Commentary by Dr. Valentin Fuster
2014;():V003T17A003. doi:10.1115/ESDA2014-20136.

The paper defines impedance control based control laws for interaction tasks with environments of unknown geometrical and mechanical properties, both considering manipulators mounted on A) rigid and B) compliant bases. In A) a deformation-tracking strategy allows the control of a desired deformation of the target environment. In B) a force-tracking strategy allows the control of a desired interaction force. In both A) and B) the on-line estimation of the environment stiffness is required. Therefore, an Extended Kalman Filter is defined. In B) the on-line estimation of the robot base position is used as a feedback in the control loop. The compliant base is modelled as a second-order physical system with known parameters (offline identification) and the base position is estimated from the measure of interaction forces. The Extended Kalman Filter, the grounding position estimation and the defined control laws are validated in simulation and with experiments, especially dedicated to an insertion-assembly task with A) time-varing stiffness environment and B) constant stiffness environment.

Commentary by Dr. Valentin Fuster
2014;():V003T17A004. doi:10.1115/ESDA2014-20196.

This paper introduces a screw theory based approach termed the freedom and actuation method (FAM) to the synthesis of decoupled spatial translational compliant parallel mechanisms (XYZ CPMs) with consideration of actuator isolation (input decoupling). This approach is unique in that (a) actuator arrangement is taken into account; and (b) it is based on a set of rules and mathematical expressions, rather than rigid-body mechanism design experience mainly used at present. According to the rules, XYZ CPMs are firstly decomposed into simple function modules, and the degrees of freedom (DOF) of each function module are identified based on the mathematical expressions. Each function module is then synthesized based only on the DOF without consideration of the actuator arrangement, so existing flexure mechanism design approaches such as the constraint-based design, the screw-theory-based method, and the freedom and constraint topology can be employed for the synthesis of the function module. The synthesis process is finally summarized and demonstrated step by step via a monolithic XYZ CPM design example. It can be envisaged that a variety of configurations of each function module can be derived under a specific DOF. Therefore, one can obtain a great number of XYZ CPM designs with consideration of actuator isolation through changing the structure of each function module, even though there is no any rigid-body mechanism design experience. The proposed FAM will enable designers to (a) decompose XYZ CPMs into the function modules; (b) yield multiple solutions to meet the DOF requirement of each compliant function module; and (c) obtain a variety of XYZ CPMs with consideration of actuator isolation.

Commentary by Dr. Valentin Fuster
2014;():V003T17A005. doi:10.1115/ESDA2014-20331.

In this paper a new method for achieving isotropic compliance at the contact point is applied to a manipulator for packaging operation. Two different manipulators are considered, namely, PR and PPR. The paper discloses some different strategies for stiffness control, with the purpose of contact force optimization. The control system acts on the controlled joint stiffness in such a way that the contact force, in the Cartesian Space, will be parallel to the displacement of the contact point. Such feature minimizes friction and wear during packaging operations and minimize tangential reactions.

Topics: Robots , Stiffness , Packaging
Commentary by Dr. Valentin Fuster
2014;():V003T17A006. doi:10.1115/ESDA2014-20343.

Schoenflies (X) motion is a 4D displacement Lie group including a spatial translation and any rotation whose axis is parallel to a given direction. Delassus parallelogram has four parallel screw (H) pairs with related pitches and the isosceles triangle is a special HHHP. After merging these two chains, an HHH-//-HHH generator of 2-DoF translation along a right helicoid is derived. It produces a 2-DoF motion mathematically modeled by a 2D submanifold of a 4D group of X-motion. Because of the product closure in an X-group, the 4-DoF generator with HHH-//-HHH loop serving as a subchain is revealed by adding two H pairs with axes parallel to fixed H axes. Parallel arrangement of two generators of the same X motion results in a new Schoenflies-motion manipulator with hybrid topology for 4-DoF pick-and-place operations. Four fixed H pairs (two double Hs) can actuate this manipulator and the two coaxial Hs must have distinct pitches. In addition, the possible design choices of special architectures are introduced for practical applications. Computer simulations of the new parallel manipulator with Schoenflies motion verify the effectiveness.

Topics: Manipulators
Commentary by Dr. Valentin Fuster
2014;():V003T17A007. doi:10.1115/ESDA2014-20407.

In this paper, a new methodology for the development of the dynamic formulation for a hybrid parallel robot is introduced. The robot includes a tripod that is serially connected on top of a hexapod in order to increase its overall workspace, while maintaining sufficient accuracy and stiffness in motion. The robot will have applications involving gripping and manipulation of large aerospace components such as a wingbox structures and panels. The dynamic formulation of the system, based on Newton-Euler and inverse kinematic equations, is presented by identifying the position vector of the actuators during motion when the system follows certain point and orientation in space. Based on the velocity and acceleration, calculated by taking derivative of the motion equation, the force on the actuator is identified. Since the position vectors of all tripod joints can change through motion, the above methodology offers less complex calculations compared with the existing methods such as using forward dynamics. A MATLAB software was developed to create a set of comprehensive dynamic equations for the overall control system design. An experimental physical hybrid robot was built in order to verify the theoretical formulations. Force sensors, connected at each actuator joint, were used to obtain the applied force on each actuator through a number of given motions. The applied forces subsequently assist to calculate the acceleration of the moving platform. The experimental actuators’ force results compare well with the proposed theoretical formulation.

Topics: Robots
Commentary by Dr. Valentin Fuster
2014;():V003T17A008. doi:10.1115/ESDA2014-20409.

This paper addresses the path planning of a hybrid parallel robot for ankle rehabilitation. The robot contains 3-DOF parallel mechanism that is attached on top of the 6-DOF hexapod. The 6-UPU-3-UPR parallel robot is developed to simulate ankle motions for the rehabilitation of post-stroke patients with an affected ankle. The inverse kinematic of hybrid parallel robot is developed in order to track the end-effector’s position through Matlab software. The calculated stroke size of each actuator is imported to apply the forward kinematic for determining the position of end-effector. The experimental and simulation values of the hexapod are compared with those of the hybrid structure through a number of exercise motion paths. The results reveal that, in general, the simulation values follow well the experimental values, although with different degrees of variation for each of the structures considered.

Topics: Robots , Simulation
Commentary by Dr. Valentin Fuster
2014;():V003T17A009. doi:10.1115/ESDA2014-20410.

In this paper, a methodology for real time identification of various singularities for various workspace types of parallel robots is proposed. Python 3D simulation software has been developed to position the moving platform of the robot’s CAD model through pre-defined rules in order to solve specific problems including singularity identification, obstacle avoidance, and path planning. The system is designed to identify the moving platform’s best possible pose. Boolean logic is used to identify valid path trajectory through parametric sweep search method. Joint constraints are checked to validate the platforms’ positions using the actuators’ stroke length, their angles, and any possible collisions. Solutions for any desired pose, based on line collision and mesh model algorithms, are then found. The path, position and workspace data are verified against a kinematic model of the robot, developed in Solid works and Matlab software tools. The simulation system has been successfully tested using various n-dimensional interpolations based on the given case study.

Topics: Robots
Commentary by Dr. Valentin Fuster
2014;():V003T17A010. doi:10.1115/ESDA2014-20449.

The study deals with the compensation of gravity loads in closed-loop mechanisms as a possible strategy for enhancing their working performance. This work focuses on the Orthoglide 5-axis, a prototypal parallel robot for milling operation, characterized by linear-delta architecture with two further serial DOFs. Starting from a general theory formerly proposed by the authors, gravity compensation of the mechanism is analytically carried out. The statically balanced Orthoglide 5-axis can be obtained by installing on one leg a proper set of extension springs and a simple additional linkage. A feasible design solution for developing the device in practice is presented. The proposed balancing device can be implemented with minor modifications of the original robot design, thus appearing a profitable solution to be possibly extended to other machinery with similar architecture.

Topics: Kinematics , Machinery
Commentary by Dr. Valentin Fuster
2014;():V003T17A011. doi:10.1115/ESDA2014-20463.

This article presents an optimization framework that is used to optimize a hydro-pneumatic balancing cylinder for industrial robots. A balancing cylinder is a device that is used to balance the gravitational torque of one of the main axes of a high-loaded serial industrial robot. The design of components for an industrial robot is multi-disciplinary, since disciplines such as multi-body dynamics, drive train design and robot control are needed. The design process is also multi-objective since the functionality of the balancing cylinder should be optimal, while its size and cost should be minimal. The article therefore also contains a discussion about multi-disciplinary and multi-objective optimization of complex products.

Commentary by Dr. Valentin Fuster
2014;():V003T17A012. doi:10.1115/ESDA2014-20482.

In this work a control law is derived to synchronize dynamics of multibody biped robots and the spring loaded inverted pendulum (SLIP) model in stance phase of running. The goal is to use the vast literature on the SLIP model dynamics for the control of real multibody robots. Three kneed biped robot models are considered in this work: with springs parallel to motors, with springs series to motors, and without springs. Dynamic equations of the multibody biped models are derived using Lagrange equation and then the applicability of the derived control law to these models are investigated using simulation. The initial state of the multibody robot is found such that its center of mass (CoM) has the same initial condition as SLIP model. Then the trajectory of its CoM is compared to SLIP model. Also motor torque profiles are compared for the models with and without springs and also for the motors with and without rotor inertias. The results show that the effect of rotor inertia is a big challenge in implementing fast biped running on real robots.

Commentary by Dr. Valentin Fuster
2014;():V003T17A013. doi:10.1115/ESDA2014-20564.

Humans have adjusted their space, their actions, and their performed tasks according to their morphology, abilities, and limitations. Thus, the properties of a social robot should fit within these predetermined boundaries when, and if it is beneficial for the user, and the notion of the task. On such occasions, android and humanoid hand models should have similar structure, functions, and performance as the human hand. In this paper we present the anatomy, and the key functionalities of the human hand followed by a literature review on android/humanoid hands for grasping and manipulating objects, as well as prosthetic hands, in order to inform roboticists about the latest available technology, and assist their efforts to describe the state-of-the-art in this field.

Topics: Humanoid robots
Commentary by Dr. Valentin Fuster
2014;():V003T17A014. doi:10.1115/ESDA2014-20606.

The evaluation of cable robot performances cannot neglect the considerable limitations introduced by cable tension bilateral bounds, i.e. the fact that neither negative nor limitless cable forces can be exerted. Therefore, such constraints must be explicitly accounted for and the indexes typically employed for parallel robots cannot be employed straightforwardly. In this work, instead of proposing a new performance index, we introduce an approach to performance evaluations which is based on the computation of the maximum force, along a specific direction, which can be exerted by the cables on the moving platform of a fully actuated or redundant cable robot. Such a computation, once extended to the whole workspace of a robot or, if needed, to any direction, openly and effectively describes the robot performances and can be extremely useful in practice. The application of the method to two fully actuated and fully constrained planar cable robots, together with a comparison with popular performance indexes, gives evidence of the method effectiveness.

Commentary by Dr. Valentin Fuster

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