ASME Conference Presenter Attendance Policy and Archival Proceedings

2016;():V003T00A001. doi:10.1115/DETC2016-NS3.

This online compilation of papers from the ASME 2016 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference (IDETC/CIE2016) represents the archival version of the Conference Proceedings. According to ASME’s conference presenter attendance policy, if a paper is not presented at the Conference by an author of the paper, the paper will not be published in the official archival Proceedings, which are registered with the Library of Congress and are submitted for abstracting and indexing. The paper also will not be published in The ASME Digital Collection and may not be cited as a published paper.

Commentary by Dr. Valentin Fuster

18th International Conference on Advanced Vehicle Technologies: Advances in Ground Vehicle Safety and Ergonomics

2016;():V003T01A001. doi:10.1115/DETC2016-59839.

Ride has always been an important aspect in vehicle design, driven by the customer’s increasing demand for vehicles with better comfort. The vibrational response of the vehicle is one of many factors contributing to the overall ride perception, with road inputs being the major excitation source. The improved capabilities of vehicle simulation models and virtual proving grounds have supplemented experimental prototype testing for tuning suspensions. Final tuning, and ride evaluation, is however still done through physical on-road testing. Four-post rig tests hold potential cost and time savings when used appropriately in the development process.

The four-post rig imposes only vertical inputs at the tire contact patches and thus it is expected for the vertical response of the vehicle to be the dominant component. The objective of this paper is to determine whether ride comfort can sufficiently be evaluated on the four-post rig using only the vertical seat Component Ride Value (CRV). The response of an instrumented vehicle on the four-post rig was measured by a tri-axial seat pad accelerometer. Vertical, longitudinal and lateral seat CRVs as well as the seat Point Ride Value (PRV) were calculated from the measured seat acceleration in the three translational directions using the BS6841 (1987) standard. The PRV is the square root of the sums of squares of the three CRVs. The CRVs and PRV, obtained from tests at various speeds and road roughnesses, were analyzed to determine whether the vertical seat CRV is sufficient in capturing the perceived ride comfort.

Results showed that the longitudinal and lateral CRVs are in excess of 26% and 63%, respectively of the dominant vertical seat CRV over the various tests. This implies that the vertical seat CRV underestimated the discomfort when compared to the seat PRV. It was also observed that the three CRVs had different sensitivities to test parameters and conditions. For example, at different speeds over the same road roughness the longitudinal CRV increased significantly more than the other two components. The differences in sensitivities may be due to the specific boundary conditions imposed on the vehicle by the four-post rig. It is concluded that the vertical seat CRV may not be sufficient to evaluate the ride comfort on a four-post rig.

Topics: Vehicles
Commentary by Dr. Valentin Fuster
2016;():V003T01A002. doi:10.1115/DETC2016-59881.

During road travel, obstacles can impede productivity or durability for many different vehicles and render discomfort or injuries for the people within. Using remote sensing techniques, information from the surroundings can be acquired and analysed to identify obstacles ahead. The subsequent analysis can create a decision support for how the vehicle or driver should act upon encountered obstacles, through either autonomous control, guidance to the driver or a combination of both. In this paper, an experimental setup was created to mimic an obstacle in the shape of a speed bump on a flat road. An RGB-D camera was used to acquire information while travelling towards the speed bump. Afterwards, the acquired information was analysed by an estimation of the normal vector for each point in a 2D depth map. The resulting data from the experiments had sufficient resolution, speed and quality to retrieve proper identify obstacles or targets indoors with an accuracy of 2%. Obstacles were measured and identified in less than 20 ms where processing time mainly comprised data transfer from the USB-bus. The obstacle identification can be used to e.g. actively control the vehicle suspension, send feedback to the driver about obstacles ahead or optimise speed and direction for autonomous vehicles.

Commentary by Dr. Valentin Fuster
2016;():V003T01A003. doi:10.1115/DETC2016-60217.

The Center for Disease Control and Prevention reports that there are approximately 1.4 million emergency department visits, hospitalizations, or deaths per year in the USA due to traumatic brain injuries (TBI) [1]. In order to lessen the severity or prevent TBIs, accurate dummy models, simulations, and injury risk metrics must be used. Ideally, these models and metrics would be designed with the use of human data. However, available human data is sparse, so animal study data must be applied to the human brain. Animal data must be scaled before it can be applied, and current scaling methods are very simplified. The objective of our study was to develop a finite element (FE) model of a Göttingen mini-pig to allow study of the tissue level response under impact loading. A hexahedral FE model of a miniature pig brain was created from MRI images. The cerebrum, cerebellum, corpus callosum, midbrain, brainstem, and ventricles were modeled and assigned properties as a Kelvin-Maxwell viscoelastic material. To validate the model, tests were conducted using mini-pigs in an injury device that subjected the pig brain to both linear and angular motion. These pigs are commonly used for brain testing because the brains are well developed with folds and the material properties are similar to human brain. The pigs’ brains were embedded with neutral density radio-opaque markers to track the motion of the brain relative to the skull with a biplanar X-ray system. The impact was then simulated, and the motion of nodes closest to the marker locations was recorded and used to optimize material parameters and the skull-brain interface. The injuries were defined at a tissue level with damage measures such as cumulative strain damage measure (CSDM). In future the animal FE model could be used with a human FE model to determine an accurate animal-to-human transfer function.

Commentary by Dr. Valentin Fuster
2016;():V003T01A004. doi:10.1115/DETC2016-60551.

To investigate the crashworthiness capacity of a M1 type commercial vehicle, the full-scale finite element (FE) model of the vehicle has been established. On the basis of the FE model, the impact simulation subject to the 100% frontal impact has been carried out, and the results have been verified with the physical impact test. The analysis of the deformation path and the energy absorption indicates that the M1 vehicle lacks sufficient frontal deformation area and its peak crash acceleration (PCA) is too high, which raises a huge challenge for the sequent development of a safety restraint system. To enhance the crashworthiness of the M1 vehicle, some structural improvements have been implemented, with adding the energy absorbing box, improving the frontal frame parts and enhancing the front door. The frontal collapsing area has been investigated in order to figure out the layout position of the energy absorbing box. The design of the aluminum foam reinforced energy absorbing box has been made by using the surrogate modeling technique. The impact simulation results of the improved M1 vehicle show a significant decrease of the PCA and a more homogeneous energy absorbing status, which verifies the validity of the proposed structures for crashworthiness improvement.

Commentary by Dr. Valentin Fuster

18th International Conference on Advanced Vehicle Technologies: Advances in Ground Vehicles Dynamics and Controls

2016;():V003T01A005. doi:10.1115/DETC2016-59207.

This paper presents a new method for optimizing mobility of a 4×4 hybrid-electric vehicle through control of wheel power distribution. First, a mobility index is used to calculate optimal power distribution for improved mobility using a Lagrangian multiplier. A control algorithm is developed for altering the wheel power distribution in order to follow a trajectory path which is calculated for optimum mobility. An inverse vehicle dynamics math model of a 4×4 vehicle is used in which a task is assigned as a required velocity to test in two simulated curvilinear maneuvers.

Commentary by Dr. Valentin Fuster
2016;():V003T01A006. doi:10.1115/DETC2016-59451.

Hypoid gears, used in automobile differentials, have a complex shape; thus, it is difficult to estimate tooth contact conditions. Therefore, a non-contact method of analysis is proposed for determining tooth contact conditions by using high-response thermography to analyze temperature distribution during meshing between the pinion and the gear. High-speed photography was performed using thermography and an extraction line was defined in the obtained thermal images to extract temperature data from them.

Furthermore, we constructed a novel model to predict tooth surface temperature distribution during tooth meshing based on a thermal network model that represents the thermal conductivity of an object by a simple RC circuit. In this report, by comparing the temperature changes obtained from the thermal images with the calculated results, we identify the thermal properties of a material from the thermal images, and discuss the effects of parameters such as heat capacity and thermal resistance. The comparison shows that infrared tooth surface imagery is effective in estimating hypoid gear tooth meshing. That is, by using infrared image and a thermal network model, heat conduction in a gear can be considered. It was confirmed that it is possible to predict temperature rise on tooth surfaces due to gear meshing.

Commentary by Dr. Valentin Fuster
2016;():V003T01A007. doi:10.1115/DETC2016-59864.

The influence of inerter on the performance of passive suspension systems is studied by comparing six different suspension architectures using a simplified quarter-car model. The suspension architectures can have one or two springs, damper, and inerter. Ride comfort, road holding, and working space are considered as the objective functions, while the suspension spring stiffness, damping ratio, and inerter equivalent mass are taken as the design variables for the multi-objective optimization. The Pareto-optimal solutions are computed and compared in the objective functions domain. The results confirm that specific inerter architectures provide advantages when all the design variables are varied. The inerter benefits are more evident in all the considered architectures, when the suspension spring stiffness is kept constant.

Commentary by Dr. Valentin Fuster
2016;():V003T01A008. doi:10.1115/DETC2016-59927.

Modern active vehicle safety systems rely on certain vehicle motion states to function. ABS requires the vehicle longitudinal speed to calculate the tire slip. The vehicle speed is typically estimated using the speed of all the wheels and is therefore dependent on the slip states of all the wheels. Electronic stability programs can also make more informed decisions if the vehicle side-slip angle is known. Currently the side-slip angle is not measured on commercial vehicles due to the cost of the sensors. The side-slip angle can however be estimated using multiple onboard vehicle measurements. However, these estimation techniques require accurate sensors and large excitations to estimate accurately. The measurement of the vehicle motion is therefore crucial for modern vehicle safety systems. This paper proposes a method whereby all 6 vehicle velocities can be measured using inexpensive forward facing mono and stereo cameras utilizing Digital Image Correlation (DIC) algorithms.

Commentary by Dr. Valentin Fuster
2016;():V003T01A009. doi:10.1115/DETC2016-60001.

The paper deals with the analysis of a manoeuvre occurring frequently before crashes. Due to an external disturbance the straight ahead running of a vehicle is degradated into an oscillating motion. The driver is required to countersteer to recover the straight ahead motion. The bifurcation analysis of a simple model describing a vehicle+driver running straight ahead is performed. The mechanical model of the car has two degrees of freedom and the related equations of motion contain the non linear tyre characteristics. The driver is described by a non linear model defined by three parameters, namely the gain (steering wheel angle per lateral deviation from desired path), the prevision distance, the reaction time delay.

Unreferenced bifurcations are discovered for the understeering vehicle. A supercritical Hopf bifurcation may occur as forward speed is increased. Also tangent (fold) bifurcations occur as the speed (or disturbance) are further increased.

The vehicle+driver model is validated by means of a number of tests performed in a track. The validation relies on the identification of driver’s parameters. The track is equipped with a plank sliding laterally when the vehicle rear axle passes on it. Such a lateral excitation applies a disturbance to the vehicle which initiates a spin to be counteracted by the driver. An analysis is performed on driver’s parameters identification. Such parameter identification seems a possible way to assess single driver’s ability to perform recovery manoeuvres.

Commentary by Dr. Valentin Fuster
2016;():V003T01A010. doi:10.1115/DETC2016-60088.

The idea behind the active kinematics suspension is to enhance its performance of vehicle dynamics. This includes improve steady and dynamic limit stability and faster transient reaction through optimized lateral and longitudinal dynamics. The driver’s benefits are: improved safety and higher driving pleasure.

To achieve more control over the position of the rear wheels and thus the tire contact patch on the ground, the active suspension introduces one independent linear actuator at each rear wheel that controls the wheels’ camber freely.

This paper will present the vehicle dynamics control logic methodology of a rear active vehicle suspension implementing the Milliken Moment Method (MMM) diagram to improve the vehicle stability and controllability, achieving gradually the front and rear axle limits.

A Multibody vehicle model has been used to achieve a high fidelity simulation to generate the Milliken Moment Diagram (MMD) also known as the CN-AY diagram, where the vehicle’s yaw moment coefficient (CN) about the CG versus its lateral acceleration (AY) is mapped for different vehicle sideslip angle and steering wheel angles. With the Moment Method computer program it is possible to create the limit of the diagram over the full range of steering wheel angle and side slip angle for numerous changes in vehicle configuration of rear camber wheels and operating conditions. The vehicle dynamics control logic uses the maps like a vehicle maneuvering area under different vehicle active configurations where vehicle’s control is most fundamentally expressed as a yawing moment to quantify the directional stability.

Topics: Kinematics
Commentary by Dr. Valentin Fuster
2016;():V003T01A011. doi:10.1115/DETC2016-60105.

A racing vehicle requires to be designed for optimum performance, stability and maneuverability considering all situations like straight line acceleration and high speed cornering. The car is driven close to its tractive limits and a control system becomes inevitable to manifest utmost performance of the car.

In this paper, the focus is on design of an electronic differential for a rear wheel driven Formula Student Electric vehicle, with each rear wheel driven by separate motors. The electronic differential (e-diff) is aimed at both straights and corners, which is fulfilled by considering objective parameters, which assist in cornering by improving yaw rate and straights by improving traction. However, in this paper we shall focus on cornering only. The paper looks at various possible control strategies for obtaining desired values of certain parameters and describes in detail implementation of a yaw rate controlled system.

A vehicle model is created on MATLAB/Simulink platform to look at changes in vehicle behavior in response to various control strategies. The model consists of vehicle dynamics and driver models developed by the authors. The coupled model simulates the vehicle performance on any given track and provides the variation of required parameters. Iterations are done and the results are used to tune the controller parameters to optimize performance on tight turns and overall lap times at the endurance event at the Formula Student competition.

Commentary by Dr. Valentin Fuster
2016;():V003T01A012. doi:10.1115/DETC2016-60308.

With the aim of prevent situations of vehicle instability against different driving maneuvers, the vehicle yaw stability becomes crucial for safe operation. This paper presents the design and simulation of a traction and a stability control system algorithms for independent four-wheel-driven electric vehicle. The stability control system consists of a multilevel algorithm divided into a high level controller and a low level controller. First, an analysis of the stability of the vehicle is performed using phase portraits analysis, both in open loop and closed loop. The stability control system is designed to generate a desired yaw moment according to the steady state cornering relationship with the steering angle input. As the test vehicle, a 14 DoF vehicle model is proposed including nonlinear tire models that allow the generation of combined forces. The vehicle model includes the powertrain dynamics. The yaw moment generation is performed using the traction and braking forces between the tires of each side of both front and rear axle. In order to generate the maximum traction forces in each of the wheels, a traction and a braking control is developed via a sliding mode controller scheme. Finally a performance comparison between a controlled and an uncontrolled vehicle is presented. The behavior of both vehicles is simulated using a classical double lane change driving maneuver.

Commentary by Dr. Valentin Fuster
2016;():V003T01A013. doi:10.1115/DETC2016-60421.

This paper presents a novel design of infrastructural traffic monitoring that performs vehicle counts, speed estimation, and vehicles classification by deploying three different approaches using two types of sensor, infrared (IR) cameras and laser range finders (LRFs). The first approach identifies passing vehicles by using LRFs and measuring the time-of-flight to the ground, which changes when vehicles pass. In the second approach, LRFs are used only to project a dotted line onto ground, and an IR camera identifies passing vehicles by recognizing the change of location of these laser dots in its images. The third approach utilizes an IR camera only and recognizes passing vehicles in each frame using background subtraction and edge detection algorithms. The design achieves high reliability because each approach has different strengths. A prototype system has been built and the field tests at a public road show promising results by achieving high reliability by having 95% accuracy in traffic counting and speed estimation.

Topics: Lasers , Sensors , Design , Traffic
Commentary by Dr. Valentin Fuster
2016;():V003T01A014. doi:10.1115/DETC2016-60537.

In this paper, the influence of chaotic motions on ride and comfort was studied through analyzing the vibration acceleration signal. By considering the stabilizer, the rigid-flexible coupling dynamics model of electric vehicle was built. The vertical vibration acceleration signals of the human trunk mass and head mass was acquired by the simulation. Two sets of data were selected according to the data of multiple simulations. In the first set, the vertical acceleration signals of the human trunk and head had the characteristics of chaotic motions, but in the second set, the signals did not have. The chaotic dynamic characteristics of the two sets were analyzed by numerical method. The total weighted acceleration root mean squared values of the two sets were calculated, and the value of the first set was larger than the second. The results showed that the ride and comfort of electric vehicle became worse when the system appeared chaotic motions. The vehicle test was carried out, it is found that the possibility of the existence of chaotic motions in driving an electric vehicle.

Commentary by Dr. Valentin Fuster

18th International Conference on Advanced Vehicle Technologies: Advances in Light Vehicles Design

2016;():V003T01A015. doi:10.1115/DETC2016-59045.

In this paper, a class of axisymmetric thin-walled tubes with two types of geometries (straight and tapered) and four kinds of cross-sections (square, rectangle, circle, ellipse) are considered as energy absorbing components under oblique impact loading. The crash behavior of these tubes are first investigated by nonlinear finite element analysis through LS-DYNA. It is found that the tapered tubes has the better crashworthiness performance than the straight ones under oblique impact regarding both specific energy absorption (SEA) and peak crushing force (PCF). Among the tapered tubes, the tapered ellipse tube (TET) has the best crashworthiness performance. Then by calculating the overall SEA considering load angle uncertainty effect, it is found that the weighting factors for different load angles are critical for evaluating the crashworthiness performance of the tubes.

Commentary by Dr. Valentin Fuster
2016;():V003T01A016. doi:10.1115/DETC2016-59092.

Stiffness of structural elements has a significant effect on the dynamics of single-track vehicles, because it influences the stability of the typical modes of this class of vehicles (weave and wobble). Up to date no specific method for measuring the critical stiffnesses of front fork, chassis and swingarm is universally recognized. This measurement is difficult chiefly for two reasons. When a structural element of a single-track vehicle is loaded at one end it undergoes both bending and torsion deformation and stiffness has to be decomposed into the bending and torsion components. The stiffness characteristics measured in static conditions may be rather different from the ones measured in the presence of dynamic loads, owing to the excitation of vibration modes. The concept of Mozzi or twist axis is used in this paper for giving a lumped element representation of stiffness of structural elements of single-track vehicles. Then the differences between stiffness characteristics measured in static and dynamic conditions are highlighted and analyzed. Finally, a novel method is proposed for the decomposition of stiffness, it makes use of the axes of the bending and torsion modes. These axes are identified by means of impulsive tests measuring the frequency response functions of three points of a rigid plate that moves with the loaded end of the structural element. Experimental results dealing with swingarm, chassis and front fork are presented.

Commentary by Dr. Valentin Fuster
2016;():V003T01A017. doi:10.1115/DETC2016-59810.

Lightweight technology is applied in the automobile industry because mass reduction is beneficial in improving fuel efficiency and reducing CO2 emissions. Apart from the car body and the power unit (the two heaviest parts of a vehicle), the driveline also has potential for a reduction in weight. The driveline transfers power to the wheels and plays an important role in the vehicle system. Vibration is induced by the road input and by unbalanced forces transmitted through the driveline to the car body. Mass reduction in the driveline could influence the dynamic behaviour of a vehicle but it is not yet clear how mass reduction affects vibration of the driveline, the vehicle ride and NVH performance — important considerations when designing a lightweight driveline. In the prototype design stage, a mathematical model provides a more flexible and less costly method of optimising the system dynamics.

In this paper, a 14 degree-of-freedom mathematical model is developed to study the dynamics of a rear drive unit (RDU). The system consists of a rear differential gearbox, left and right constant velocity joints and driveshafts, a rear sub-frame, and bushings between the RDU and the sub-frame and between the sub-frame and the car body. Excitations from the rear wheels, rear suspensions, and input shaft were considered. The vertical acceleration at the rear sub-frame was calculated and correlated with a calibrated multi-body dynamic model of the vehicle developed in a parallel study.

Using a fractional factorial design with the vehicle travelling on a smooth road at various speeds, a sensitivity analysis was carried out with the developed mathematical model to identify the contributions of the mass properties of the RDU and the bushing parameters to the vibration at the centre of gravity (COG) of the rear sub-frame.

Results indicate that the effects of design parameters on the rear sub-frame vibration vary according to the vehicle speed. For vibration at the rear sub-frame, the most influential factors are the masses of the rear differential gearbox and the driveshaft, and the stiffness of the front right bushings between the RDU and the sub-frame. The stiffness of the front left bushing between the RDU and the sub-frame also has considerable effect on the subsystem response but only at higher speeds. Reducing the mass of the CV joint is beneficial in decreasing the vertical vibration at the COG of the rear sub-frame, while reductions in masses of the gearbox and the driveshafts tend to slightly increase the vertical vibration at the same location. However, the adverse effect brought by lightweight differential gearbox and driveshafts on vibration is relatively small that may be hardly detected by passengers. The adverse effect (if any) can be compromised by adjusting the stiffness of the front bushings between the gearbox and the sub-frame.

Commentary by Dr. Valentin Fuster
2016;():V003T01A018. doi:10.1115/DETC2016-60287.

Aerodynamic drag is the main opposing force that a cyclist has to overcome when cycling on level ground at moderate-to-high speeds. Therefore, the aerodynamic study of the bike-cyclist set has been identified as a key factor for the analysis and improvement of performance. Although there are many reference aerodynamic studies, for the specific analysis of a bike-cyclist set it is necessary to take into account the particular influence of the cyclist’s body shape, cyclist position and cycling equipment on aerodynamic drag. In addition, there are quantitative studies focused on analyzing aerodynamic drag using numerical and experimental methodologies; nonetheless, these studies are generally not complementary or comparative. The aim of this paper is to present the first stage of a current work that seeks to develop a complementary methodology for the aerodynamic drag analysis using numerical and experimental studies. In this stage, a numerical study based on Computational Fluid Dynamics (CFD) is presented. A digitalized cyclist body model is analyzed while the mesh characteristics and the results of the CFD simulations are addressed. On the other hand, field experimental tests were carried out by the same cyclist to determine the power demand at two cyclist’s body positions. A method for monitoring the cyclist’s body position in order to achieve repeatable positions during experimental trials is presented. Complementary information for the aerodynamic evaluation is obtained through the numerical and experimental studies, and the aerodynamic drag area results from both approaches is compared.

Commentary by Dr. Valentin Fuster
2016;():V003T01A019. doi:10.1115/DETC2016-60331.

During the individual time-trial competitions in cycling, the cyclist’s skills are essential, but it is also important the race strategy. The race strategy includes the manner in which the cyclist competes and the selection and set-up of the cycling equipment. For hilly time-trials, part of the race strategy consists of the right selection of the bike type. Depending on the characteristics of the road such as total distance and altitude profile, a time-trial bike or a traditional road bike could be used. Additionally, in some races it is possible to change bike type as a part of the strategy. This strategy seeks to take advantage of time-trial bikes during low gradient sections and to take advantage of road bikes during high gradient sections. The purpose of this work is to plan an optimal bike change strategy to determine if it is advantageous to change the bike type, and if so, to find the point of the route where the change minimizes race time. The optimal planning methodology is based on a bike model, a simplified altitude profile and an optimization problem. A model parameters identification process is performed based on experimental tests in a hilly route. This route is used as a case study for the optimal planning of the bike change strategy.

Topics: Bicycles
Commentary by Dr. Valentin Fuster

18th International Conference on Advanced Vehicle Technologies: Advances in Methods for Ground Vehicle Systems Design

2016;():V003T01A020. doi:10.1115/DETC2016-59279.

As an important component in brake systems, the Brake-by-Wire system has attracted great attention recently with the development of emerging energy vehicle and modern passenger cars. The main feature of the Brake-by-Wire system, in contrast to the conventional braking system, is the elimination of the dependence of the vacuum booster on engine vacuum through decoupling of the brake pedal and the brake actuator. The influences from road surface to the driver’s brake feeling can also be eliminated by employment of a brake pedal simulator. The Brake-by-Wire system can greatly improve the automotive safety performance of modern passenger cars, including response time, control capability and stability. As much as the system shows great promise, drawbacks should be addressed as well. For example, design theories on system structure, reliable control strategies, high energy consumption, the modeling of global Brake-by-Wire non-linear dynamic system, poor working conditions and high maintenance costs are major concerns.

This paper aims to provide a timely and comprehensive review on the state-of-the-art Brake-by-Wire system used in modern passenger cars. Variety of major components are compared in order to get a more reliable and lower energy consumption system, which includes actuators, pedal simulators and backup brake systems. Researches on control strategies as well as future research direction of Brake-by-Wire system are also discussed.

Topics: Wire , Automobiles , Brakes
Commentary by Dr. Valentin Fuster
2016;():V003T01A021. doi:10.1115/DETC2016-59475.

Planetary gear trains are presently widely used in various machines owing to their many advantages. They, however, suffer from problems of noise and vibration due to their structural complexity. Moreover, their dynamic characteristics are yet to be fully understood. Although several studies have been conducted on two-axis driving and displacement of planet gear, none has considered three-axis driving. In the present study, the general driving conditions of a planetary gear train, including during three-axis driving, were investigated based on the theory of instant center. Ideal driving condition is proposed based on the experimental result on three-axis driving which was tested on an original fully wireless test stand.

Commentary by Dr. Valentin Fuster
2016;():V003T01A022. doi:10.1115/DETC2016-59593.

This paper presents a method for turbocharging single cylinder four stroke internal combustion engines, an experimental setup used to test this method, and the results from this experiment. A turbocharged engine has better fuel economy, cost efficiency, and power density than an equivalently sized, naturally aspirated engine. Most multi-cylinder diesel engines are turbocharged for this reason. However, due to the timing mismatch between the exhaust stroke (when the turbocharger is powered) and the intake stroke (when the engine intakes air), turbocharging is not used in commercial single cylinder engines. Single cylinder engines are ubiquitous in developing world off-grid power applications such as tractors, generators, and water pumps due to their low cost. Turbocharging these engines could give users a lower cost and more fuel efficient engine. The proposed solution is to add an air capacitor, in the form of a large volume intake manifold, between the turbocharger compressor and the engine intake to smooth out the flow.

This research builds on a previous theoretical study where the turbocharger, capacitor, and engine system were modeled an-alytically. In order to validate the theoretical model, an experimental setup was created around a single cylinder four stroke diesel engine. A typical developing world engine was chosen and was fitted with a turbocharger. A series of sensors were added to this engine to measure pressure, temperature, and power output. Our tests showed that a turbocharger and air capacitor could be successfully fitted to a single cylinder engine to increase intake air density by forty-three percent and peak power output by twenty-nine percent.

Commentary by Dr. Valentin Fuster
2016;():V003T01A023. doi:10.1115/DETC2016-59996.

The thermal and structural behaviour of carbon-carbon disc brake and pads have been studied.

A literature review was conducted to investigate recent research that has been completed in many areas related to thermo-elastic modelling of braking systems.

The friction forces generated during braking between brake pads and disc produce high thermal gradients on the rubbing surfaces. Thermo-elastic deformation results in contact concentration, leading to the non uniform distribution of temperature and pressure making the disc susceptible to hot bands and hot spots formation.

The present paper proposes a simplified modelling concept useful in the preliminary brake system design phase. Furthermore, a full finite element model related to structural/thermal analysis is presented as well. The thermo-elastic behaviour has been investigated experimentally under different braking conditions.

The models (simplified and full FE) have been validated experimentally on the basis of indoor tests results.

The accuracy of the two models is good, but the computational effort required by the full FE model can be very high.

Commentary by Dr. Valentin Fuster

18th International Conference on Advanced Vehicle Technologies: Advances in Methods for Tire Design and Mechanics

2016;():V003T01A024. doi:10.1115/DETC2016-59096.

The parameter values used in a tire model directly determine the prediction accuracy of the model. Poorly identified parameters lead to incorrect prediction of tire performances. The optimization algorithm used for parameter identification has a huge impact on the quality of the identified parameters for a tire model. In this paper, four different optimization algorithms in MATLAB, including local optimization algorithms (fminsearchcon and patternsearch) and global optimization algorithms (particleswarm and GA-genetic algorithm), are applied to identify the parameters of a newly proposed in-plane flexible ring tire model based on one cleat experiment results, respectively. Their performances are compared in terms of the prediction accuracy, efficiency and some other aspects. After the comparison, the most suitable optimization algorithm for tire model parameter identification is obtained. Finally, the parameters that are identified based on the set of parameters from the most suitable algorithm are used to predict the other cleat test conditions to further validate the tire model.

Commentary by Dr. Valentin Fuster
2016;():V003T01A025. doi:10.1115/DETC2016-59105.

Piezoelectric harvesters used for feeding the sensors of intelligent tires experience impulse excitation when the harvester enters the contact patch of the tire. The design, development and set up of advanced harvesters characterized by new materials, optimized shape and specific solutions for tuning require the possibility of testing prototypes in the laboratory simulating the actual working conditions and in particular impulsive events. The aims of tests are manifold: verification of mechanical and electrical performance, comparison with numerical models and updating, identification of parameters of the harvester that are difficult to measure directly. In this paper a testing method based on hammer excitation of an harvester mounted on a specific testing rig is presented. The testing rig is simple and low cost. It makes possible the measurement of the frequency response function (FRF) between output voltage and input acceleration. Design requirements for the testing rig are reported and a validation of the realized system is presented. A multimodal mathematical model is developed in MATLAB to simulate the impulse response of the harvester and in particular to stress the effect of higher order modes. Results show the dominance of the fundamental mode in the response of the tested harvesters. Calculated and experimental results are in good agreement.

Commentary by Dr. Valentin Fuster
2016;():V003T01A026. doi:10.1115/DETC2016-59732.

This paper presents a method to estimate the parameters of a longitudinal dynamic model using on-road testing of an electric vehicle. Data acquisition was undertaken on our test vehicle, a Toyota Rav4EV 2012, by collating signals from three different sources: Vehicle Measurement System (VMS) (consisting of wheel force, torque, wheel spin, wheel speed and position sensors), Global Positioning System (GPS) and the Controller Area Network (CAN) of the vehicle. A MATLAB/Simulink based non-linear least square parameter estimation algorithm was used to identify the vehicle parameters including the mass, location of center of gravity, frontal area, coefficient of drag, wheel inertia and road load parameters of the vehicle. A 14 degrees of freedom (DOF), longitudinal dynamics model of the Rav4EV was developed in the MapleSim software using the estimated parameters. The accuracy of the identified parameters and the model was validated by comparing the model output against the experimental data.

Commentary by Dr. Valentin Fuster
2016;():V003T01A027. doi:10.1115/DETC2016-59944.

With all wheeled vehicles, the tire contact patch is the only connection between the vehicle and the road. All the forces, except for aerodynamic forces, that are acting on the vehicle are generated in the tire contact patch. The size, shape and the pressure distribution of the contact patch are important to the performance, ride qualities and handling characteristics of a vehicle. Tire footprint studies are essential in understanding tire force generation and tire wear mechanisms. It is thus important to accurately determine the tire contact patch size and dimensions. This paper discusses various methods for measuring the static tire contact patch dimensions. A set of tests are conducted on various tires and at different inflation pressures. These tests are used to discuss the suitability of the methods depending on the type, size, load and contact surface of the tire. A list of advantages and disadvantages for each method is generated and discussed. The aim of this paper is not to study the tire footprints but to discuss the various testing methods. Insight into the different methods can help to select the suitable method for future tire contact studies.

Topics: Tires
Commentary by Dr. Valentin Fuster

18th International Conference on Advanced Vehicle Technologies: Advances in Military and Commercial Ground Vehicle Design

2016;():V003T01A028. doi:10.1115/DETC2016-59094.

Although blast mitigation seats are historically designed to protect the 50th percentile male occupant based on mass, the scope of the occupant centric platform (OCP) Technology Enabled Capability Demonstration (TEC-D) within the U.S. Army Tank Automotive Research Development Engineering Center (TARDEC) Ground System Survivability has been expanded to encompass lighter and heavier occupants which represents the central 90th percentile of the military population. A series of drop tower tests were conducted on twelve models of blast energy-attenuating (EA) seats to determine the effects of vertical accelerative loading on ground vehicle occupants. Two previous technical publications evaluated specific aspects of the results of these drop tower tests on EA seats containing the three sizes of anthropomorphic test devices (ATDs) including the Hybrid III 5th percentile female, the Hybrid III 50th percentile male, and the Hybrid III 95th percentile male. The first publication addressed the overall trends of the forces, moments, and accelerations recorded by the ATDs when compared to Injury Assessment Reference Values (IARVs), as well as validating the methodology used in the drop tower evaluations1. Review of ATD data determined that the lumbar spine compression in the vertical direction could be used as the “go/no-go” indicator of seat performance. The second publication assessed the quantitative effects of Personal Protective Equipment (PPE) on the small occupant, as the addition of a helmet and Improved Outer Tactical Vest (IOTV) with additional gear increased the weight of the 5th percentile female ATD more than 50%2. Comparison of the loading data with and without PPE determined that the additional weight of PPE increased the overall risk of compressive injury to the lumbar and upper neck of the small occupant during an underbody blast event.

Using the same data set, this technical paper aimed to evaluate overall accelerative loading trends of the 5th percentile female ATD when compared to those of the 50th percentile male ATD in the same seat and PPE configuration. This data trend comparison was conducted to gain an understanding of how seat loading may differ with a smaller occupant. The focus of the data analysis centered around the lumbar spine compression, as this channel was the most likely to exceed the IARV limit for the 5th percentile female ATD. Based on the previous analysis of this data set, the lightest occupant trends showed difficulty in protecting against lumbar compression injuries with respect to the 5th percentile female’s IARV, whereas the larger occupants experienced fewer issues in complying with their respective IARVs for lumbar compression. A review of pelvis acceleration was also conducted for additional kinetic insight into the motion of the ATDs as the seat strokes. This analysis included a review of how the weight and size of the occupant may affect the transmission of forces through a stroking seat during the vertical accelerative loading impulse.

Topics: Testing , Compression
Commentary by Dr. Valentin Fuster
2016;():V003T01A029. doi:10.1115/DETC2016-59509.

Multi-axle land vehicles with independent drive actuation on multiple axles offer improved stability and traction on various road surfaces. This is possible by exploiting the redundancy of the drive system to generate additional yaw moment and to maximize the utilization of individual tire-road contacts without significant extra power consumption by the drive motors. This paper aims at improving the efficiency of torque allocation with the addition of active steering while enhancing the dynamic performance of the independent hub motor driven multi-axle vehicles. The control algorithm outlined here employs a two-level scheme. The higher level computes the desired global control efforts that are needed to track the reference yaw rate and slip angle state responses generated by a reference vehicle model, and the lower level executes optimal control allocation with a cost function that simultaneously takes into account 1) maximization of the tire utilization on all axles considering dominant tire nonlinearities, and 2) minimization of the actuation efforts of the active steering system and the distributed motor torques. The validity of the proposed algorithm is verified via comparison of the simulations of the control allocation scheme applied to a high fidelity multi-axle vehicle under several aggressive test maneuvers with different actuation configurations. The results suggest that the addition of active steering provides lower actuator power consumption and tire usage while ensuring enhanced lateral and longitudinal dynamic performance for the vehicle.

Topics: Motors , Vehicles
Commentary by Dr. Valentin Fuster
2016;():V003T01A030. doi:10.1115/DETC2016-59823.

In the measurement of the inertia properties of rigid bodies (mass, centre of gravity location and inertia tensor) the structures carrying the body under test are usually considered to be rigid. This assumption is less and less satisfied as the dimensions of the body grow. Consequently, the forces exchanged between the body and the structures can be large enough to deform the structure and affect the measurement, especially the location of the centre of gravity.

In this paper, with special reference to the InTenso+ Measuring System of the Politecnico di Milano, the effects of the deformation of the test rig structure when measuring large bodies is investigated. A theoretical analysis is performed by using a flexible multibody mathematical model of the test rig. The deformation of the test rig is deeply investigated by a dedicated FEM model. The results of the theoretical analysis are then validated by measuring the inertia properties of a light truck.

It turns out that the deformation of the test rig can actually affect the measurement. This deformation can be compensated by a proper mathematical procedure. The method can, consequently, be employed also for very large bodies for which the construction of a sufficiently rigid structure as to neglect its deformation is practically impossible.

Commentary by Dr. Valentin Fuster
2016;():V003T01A031. doi:10.1115/DETC2016-59922.

The Vehicle Dynamics Group (VDG) at the University of Pretoria has developed a semi-active hydro-pneumatic suspension system for an off road vehicle. The suspension system can switch its characteristics between two discrete spring characteristics as well as two discrete damping characteristics all incorporated in a single suspension strut. This original 4-State Semi-active Suspension System (or 4S4), switches between discrete characteristics through the control a set of solenoid valves. Recently, the 4S4 was further developed with the aim of extending its damping characteristics to be continuously variable through the use of Magneto-rheological (MR) technology. The newly developed MR4S4 prototype received a re-designed flow path which channels the MR suspension fluid through two independent magnetic valves (flow orifice enclosed by coils) in parallel. The damping characteristics of each of the valves are controlled independently by the application of electric currents through damper coils. These valves are also able to block flow completely to achieve the discrete spring characteristics through switching flow to the independent accumulators.

However, in order to ensure that this new technology could be effectively applied and controlled a model of the MR4S4 needed to be developed.

This paper describes the development and validation of a physics based model which is able to capture the overall dynamics and properties of the MR4S4 suspension system. Importantly, the aim of the research was to appropriately capture the physical properties of both the gas as well as the MR fluid as it interacts with the suspension displacements and forces. This model would aid further research in the development of control strategies and provide insight through simulation studies on the systems’ influence on vehicle dynamics.

Commentary by Dr. Valentin Fuster
2016;():V003T01A032. doi:10.1115/DETC2016-60390.

To improve the vehicle fuel economy and prolong the thermal fatigue life of the traditional shock absorbers, energy regenerative electromagnetic shock absorbers have attracted wide attentions. This paper discusses a hydraulic electromagnetic shock absorber (HESA), which has high reliability. A dynamic model of HESA is created in this paper, which shows that the damping force of HESA is composed of the electric damping force, friction damping force, the inerter force and the accumulator force. Influences of hydraulic motor and pipe diameter on the force are analyzed based on the modeling. The parameters of the nonlinear component accumulator are also studied experimentally. Both modeling and lab tests show that the accumulator force can counteract part of the effect of the inerter force, which is greatly beneficial for the vehicles. The damping characteristics and energy harvesting characteristics are also studied based on the lab tests. Results show that the damping coefficient of HESA ranges from 12000Ns/m to 92000Ns/m at a vibration input of 3Hz frequency and 5mm amplitude, and HESA has a unique damping characteristic which needs to be further studied for vehicle dynamics. In addition, the efficiency of HESA can achieve 30% at a vibration input of 3Hz frequency and 7mm amplitude with external resistance of 4 ohms. The average power at this excitation can reach 102 watts.

Commentary by Dr. Valentin Fuster

18th International Conference on Advanced Vehicle Technologies: Advances in Vehicle Electrification and Powertrain Design

2016;():V003T01A033. doi:10.1115/DETC2016-59276.

The challenge of meeting the Corporate Average Fuel Economy (CAFE) standards of 2025 has resulted in the development of systems that utilize alternative energy propulsion technologies. To date, the use of solar energy as an auxiliary energy source of on-board fuel has not been extensively investigated, however. The authors investigated the design parameters and techno-economic impacts within a solar photovoltaic (PV) system for use as an on-board auxiliary power source for the internal combustion engine (ICE) vehicles and plug-in electric vehicles (EVs). The objective is to optimize, by hybridizing, the conventional energy propulsion systems via solar energy based electric propulsion system by means of the on-board PVs system.

This study is novel in that the authors investigated the design parameters of the on-board PV system for optimum well-to-tank energy efficiency. The following design parameters were analyzed: the PV device, the geographical solar location, thermal and electrical performances, energy storage, angling on the vehicle surface, mounting configuration and the effect on aerodynamics. A general well-to-tank form was derived for use in any other PV type, PV efficiency value, or installation location. The authors also analyzed the techno-economic value of adding the on-board PVs for ICE vehicles and for plug-in EVs considering the entire Powertrain component lifetime of the current and the projected price scenarios per vehicle lifetime, and driving by solar energy cost ($ per mile). Different driving scenarios were used to represent the driving conditions in all the U.S states at any time, with different vehicles analyzed using different cost scenarios to derive a greater understanding of the usefulness and the challenges inherent in using on-board PV solar technologies.

The addition of on-board PVs to cover only 1.0 m2 of vehicle surfaces was found to extend the daily driving range to up to 2 miles for typical 2016 model vehicles, depending upon on vehicle specifications and destination, however over 7.0 miles with the use of extremely lightweight and aerodynamically efficient vehicles in a sunny location. The authors also estimated the maximum possible PV installation area via a unique relationship between the vehicle footprint and the projected horizontal vehicle surface area for different vehicles of varying sizes. It was determined that up to 50% of total daily miles traveled by an average U.S. person could be driven by solar energy, with the simple addition of on-board PVs to cover less than 50% (3.25 m2) of the projected horizontal surface area of a typical mid-size vehicle (e.g., Nissan Leaf or Mitsubishi i-MiEV). Specifically, the addition of the proposed PV module to a 2016 Tesla Model S AWD-70D vehicle in San Diego, CA extended the average daily range to 5.2 miles in that city. Similarly, for the 2016 BMW i3 BEV in Texas, Phoenix, and North Carolina, the range was extended to more than 7.0 miles in those states.

The cost of hybridizing a solar technology into a vehicle was also estimated for current and projected prices. The results show for current price scenario, the expense of powering an ICE vehicle within a certain range with only solar energy was between 4 to 23 cents per mile depending upon the vehicle specification and driving location. Future price scenarios determined the driving cost is an optimum of 17 cents per mile. However, the addition of a PV system to an EV improved the economics of the system because of the presence of the standard battery and electric motor components. For any vehicle in any assumed location, the driving cost was found to be less than 6.0 cents per mile even in the current price scenario.

The results of this dynamic model are applicable for determining the on-board PV contribution for any vehicle size with different powertrain configurations. Specifically, the proposed work provides a method that designers may use during the conceptual design stage to facilitate the deployment of an alternative energy propulsion system toward future mobility.

Commentary by Dr. Valentin Fuster
2016;():V003T01A034. doi:10.1115/DETC2016-59339.

A new class of electric motors with hybrid-field topology is introduced. Departing from conventional radial- or axial-field designs, the motors feature three-dimensional magnetic flux paths, which are enabled by an advanced isotropic soft magnetic material produced by a unique additive-manufacturing process based on spray forming. The motors provide considerably higher power output (40% higher power density) and improved energy efficiency (up to 15% lower losses) compared to the state of the art. A prototype spray-formed hybrid-field motor has been designed and constructed, and the size, power and efficiency benefits have been demonstrated.

Commentary by Dr. Valentin Fuster
2016;():V003T01A035. doi:10.1115/DETC2016-59955.

A novel hybrid-electric transmission concept was sought that yields higher acceleration and smoother gear-shifts compared to existing dual-clutch systems while improving the energy efficiency of the vehicle. After evaluating a range of strategies, the elimination of the clutch was identified as a viable method for reducing the vehicle’s effective inertia and viscous losses. The proposed architecture implements a single electric motor, and two separate shafts for odd and even gears, to replace the functions of a clutch. High acceleration rates can be achieved using the electric motor when launching the vehicle. Furthermore, the torque from the electric motor (EM) and internal combustion engine (ICE) can be simultaneously delivered through the two shafts to sustain this high acceleration. A 0 to 100 km/hr time of 3.18 s was simulated for a 1600 kg vehicle using a 180 kW EM and 425 kW ICE. In addition, the EM can be used to match the speeds of consecutive gears on the two shafts to reduce jerk while shifting. Shift durations were found to vary between 0.2 and 0.9 s using this strategy. Other benefits include regenerative braking and the removal of the reverse gear since the EM can rotate in either direction. It was also found that the vehicle can be operated on only electric power in urban settings — represented by the NEDC driving cycle — if the battery is recharged through regenerative braking, and by the ICE the vehicle is stopped.

Commentary by Dr. Valentin Fuster
2016;():V003T01A036. doi:10.1115/DETC2016-60335.

The design and control of hybrid-electric vehicle (HEV) powertrains presents an optimization problem to balance the trade-off between multiple objectives, such as fuel economy, driv-ability, and emissions. However, current design methodologies do not simultaneously incorporate all of these three considerations into both the sizing and control layers of the optimization problem. This paper first demonstrates that the trade-offs between these objectives can be non-trivial in the HEV control problem. This motivates the need for a systematic design procedure that can take all three objectives into account. To address this need, the paper describes the development of a new and efficient design framework called the Hybrid-Vehicle Design Tool (HVDT), which adopts a bi-level optimization strategy. Efficiency is achieved by introducing a neural-network-based meta-model to predict the performance of the optimal control strategy obtained using Dynamic Programming (DP). To demonstrate the HVDT, a small HEV is designed for the UDDS and HWFET driving cycles separately. Results show that the optimized design can reduce fuel consumption, improve emissions and improve driv-ability when compared to the nominal design obtained using first principle design methodologies. Additionally, compared to using DP directly in the bi-level optimization, using the meta-model reduces the simulation from 238 to 16 days (93%) and from 132 to 16 days (88%) for the UDDS and HWFET cycles, respectively, with an acceptable compromise in the accuracy of predicting the performance of DP.

Commentary by Dr. Valentin Fuster
2016;():V003T01A037. doi:10.1115/DETC2016-60562.

Temperature differential power generation made by the thermoelectric material is an effective way to recover waste heat and enhance the internal combustion engine energy utilization efficiency. At present, single-phase coolant is applied to the thermoelectric material cold-end, but the temperature control effect is not ideal except for low power generation. In this research, a two-phase cooling system is designed to stabilize the thermoelectric material cold-end temperature. Firstly, the thermal characteristics of the diesel engine exhaust gas and the Mg2Si0.3Sn0.7 thermoelectric material are obtained through experiments. Secondly, the heat-transfer model of the heat-exchange system is established through the set system’s geometrical parameters. Finally, the characteristics of temperature between the thermoelectric material’s cold-end and hot-end besides the heat transfer rate are acquired, thus the power generation performance of the thermoelectric material would be gained. The result shows that under the engine’s experiment working conditions of 1300rpm to 2100rpm, comparing to the single-phase cooling system, the two-phase cooling system could ensure the coolant’s cold-end temperature in the range of 102 °C to 106 °C , which increases the thermoelectric material temperature difference more than 50°C. Correspondingly, the power generation increases about 122W to 2785W.

Commentary by Dr. Valentin Fuster

13th International Conference on Design Education: Best Practices in Design Education

2016;():V003T04A001. doi:10.1115/DETC2016-59251.

This study explores whether changing design objectives during introductory mechanical engineering courses would improve design novelty and quality when these courses offer a competition element. Design fixation can occur when students are presented with the same design objective because the institutionalized “best” solutions are transferred from semester to semester and student to student. Design competitions are a popular way to teach the design and construction components, often with a focus on robotics. Some competitions are newly designed and rebuilt every single semester, requiring advanced planning and often high budgets. Others reuse a similar competition from year to year without any changes to the design objectives. This paper tries to answer whether or not students are building more novel designs when the competition changes from semester to semester. In this study, robots from four different configurations for a design-and-build activity were analyzed. The unchanged design prompt and 3 semesters of different design prompts were included in the study. The evaluations of the robots were based on the performance of the robots, the type and quality of the designs, and the relationship between the design competition and the robots. Results from this study suggest that changing design objectives (i.e. challenges found in a robotic competition) allows for a wider variation in the designs. While the average novelty did not change, students were no longer limited to and fixated on a very small range of designs.

Commentary by Dr. Valentin Fuster
2016;():V003T04A002. doi:10.1115/DETC2016-59295.

Engineering students are often unaware of manufacturing challenges introduced during the design process. Students tend to design parts that are either very difficult or impossible to manufacture because they are unaware of the intricacies and limitations of the manufacturing processes available. Design for manufacturability (DFM) education must be improved to help address this issue. This work discusses a vision for the implementation of a rapid method for facilitating DFM education in terms of subtractive and additive manufacturing processes. The goal is to teach students about how their designs impact the ease and cost of manufacturing, in addition to giving them knowledge and confidence to move fluidly between additive and subtractive manufacturing mindsets. For subtractive manufacturing, this is accomplished through a high-performance-computing accelerated and parallelized trajectory planning software package that enables students to visualize the subtractive manufacturability of the parts they design as rapidly as they get feedback when using additive manufacturing processes. Implementation of the subtractive manufacturability analysis tool in a sophomore-level design class is presented, along with the assessment of the students’ conceptual manufacturing-related understanding.

Commentary by Dr. Valentin Fuster
2016;():V003T04A003. doi:10.1115/DETC2016-60066.

The recent years have witnessed a new generation of Makers working with new ways of knowledge generation for creation and sharing of digital and physical products. While this development has started within collaborative and grass roots organised networks; educational institutions have also embraced it by opening makerspaces and adopting elements of the Maker Movement in their offerings. This paper investigates how university driven makerspaces can affect engineering design and product development education trough a case study. We provide our findings based on interviews and data collected from educators, students the administrative and workshop staff of the makerspace. The findings are used to outline the challenges in incorporating the offerings of makerspaces. By discussing these challenges we identify opportunities for turning university makerspaces into innovation hubs and platforms that can support engineering design education.

Commentary by Dr. Valentin Fuster
2016;():V003T04A004. doi:10.1115/DETC2016-60333.

While research has been conducted to study the use of concept selection methods in design education, few studies have focused on the influence of these methods on individual students’ and teams’ thought processes in grade-dependent class projects. In order to fill this research gap, the current study was designed to compare the influence of two concept selection methods, the Concept Selection Matrix (CSM) and a new adjective assessment method called the Tool for Assessing Semantic Creativity (TASC), through an experimental study in two sections of a first year engineering design class. The results of the study show that while students were equally confident in the concept ratings from the CSM and TASC methods, they reported that they were more likely to select ideas ranked highly in the CSM method. However, subsequent analysis revealed no difference between the common elements in the ideas rated highly by the two methods and the final design ideas produced.

Commentary by Dr. Valentin Fuster
2016;():V003T04A005. doi:10.1115/DETC2016-60382.

Cognitive Empathy, often referred to as perspective taking, refers to the ability to identify and understand details about another’s experience so that one can understand why people may think and feel the way that they do. In recent years the need for designers to develop Cognitive Empathy skills has been recognized and has given rise to human-centered design and empathic design. Many mechanical engineering and design departments offer courses and have programs in these emerging topics. Mechanical engineers need to have basic understanding of Cognitive Empathy to function in today’s workplace. In addition, most mechanical engineering undergraduate programs do not have a diverse student body representative of the general population. Although there are many reasons, we believe that having a welcoming, inclusive environment is a precursor to improving diversity and thus should be an important consideration in mechanical engineering education. We propose that introducing carefully designed training on Cognitive Empathy in design courses could result in (i) a more welcoming and inclusive environment and (ii) a new generation of designers better equipped to consider the users. In this paper we present an “Intercultural Cognitive Empathy” training that was given to all mechanical engineering seniors at the University of Oklahoma to create a more inclusive environment. The students in a senior design course received the training at the beginning of the semester, before forming their design teams, so that they could use the skills to better communicate with each other. Cognitive Empathy research provided the foundation for the training and intercultural active learning components were also integrated. A student survey, done at the end of the semester, showed that students retained and used different components of the training throughout the semester. The assessment strongly suggests that this training should be part of the regular curriculum.

Commentary by Dr. Valentin Fuster

13th International Conference on Design Education: Design Education in the Curriculum

2016;():V003T04A006. doi:10.1115/DETC2016-59035.

Uncertainty commonly exists in engineering applications, especially in a design process. Quantifying and managing uncertainty is often a core consideration during the design stage. Due to its importance in engineering practices, uncertainty is gradually introduced and taught in a number of engineering courses. Uncertainty topics, however, are still limited and the teaching materials on uncertainty are still currently lacking. This paper focuses on possible topics that could be introduced in various engineering courses, particularly in design courses. The topics cover the following aspects: identify and take actions on potential failure modes, account for system reliability in the early design stage, quantify the effect of uncertainty, and mitigate the effect of uncertainty in latter design stages. This paper also introduces basics of related design methodologies, such as reliability-based design, robust design, and design for six sigma in order for interested educators to develop familiarity of uncertainty. This paper also reports the implementation and experience of uncertainty education at the Missouri University of Science and Technology.

Commentary by Dr. Valentin Fuster
2016;():V003T04A007. doi:10.1115/DETC2016-59047.

Decision making is an important feature of design. Although engineering design refers to the design of products and technical systems, design activities occur in many other professions, including education. As education moves from teaching to learning, engineering faculty are becoming course designers who make many decisions when designing a course. Although many course design processes have been described, previous work has not considered course design as an interrelated set of decisions. To plan a course, a designer must make decisions. The course designer must select following elements: the purposes of the course, the content, its sequence, the instructional resources, and the instructional processes. These decisions occur at different “levels”: some determine “small” parts of the course (such as the media for one activity), and some determine “large” parts of the course (such as the sequence of topics). This paper, an initial step towards decision-based instructional design, describes the decisions that need to be made to design a typical academic course, the different ways in which these decisions are logically related to each other, and the objectives relevant to these decisions. These descriptions, which focus on the logical relationship between the decisions, do not form a complete course design process. Designing better courses requires selecting better alternatives for the many decisions that must be made. The objectives used to guide these decisions are thus a critical part of course design. These objectives include meeting a specific need in a satisfactory way, using an established rule or heuristic, maximizing effectiveness, optimizing a metric that is correlated with effectiveness, reducing the costs and resources required to develop and offer the course, and maximizing cost-effectiveness. This paper presents a simple model that describes the relationships between the course design, the instructor’s actions, the students’ actions, the initial and recurring costs of a course, the course effectiveness, and the utility (value) of the course. Based on this model, one could formulate a comprehensive instructional design problem: select the course design that maximizes the expected utility (value). Although there may be other factors that should be included in this model and we may currently be far away from formulating and solving this comprehensive instructional design problem, it can serve as a goal to motivate future research. This paper presents a new perspective for understanding course design, and elaborating this view can increase our understanding of engineering education and help those who are designing engineering courses. Describing these steps as decisions is an important step towards helping instructors make better decisions, which can yield more effective course designs and enhance student learning. This paper adds to our knowledge of engineering education by identifying the types of decisions involved and the objectives that can be used to make those decisions.

Commentary by Dr. Valentin Fuster
2016;():V003T04A008. doi:10.1115/DETC2016-59640.

Functional modeling as a design methodology is often covered in engineering design texts as a tool for transforming “customer speak” into “engineering speak.” There is little to no empirical data, though, that clearly demonstrates that learning functional modeling actually improves students’ engineering design skills. The overall objective of this project is to determine the impact of teaching function on engineering students’ design synthesis abilities. This paper focuses on preliminary data collected as a part of the longitudinal study. Students were asked to generate functional models of functionally similar systems at two points during an engineering design course: (1) once as a homework assignment immediately following the introduction of the topic and (2) again as a low stakes in-class activity seven weeks later. This paper will present the comparison of models created at both data points. Student models at each time point are analyzed using a validated 18-question rubric. The results provide promise that, in general, students retain their modeling ability, but there are noted characteristic differences between homework-generated functional models and those generated later in the semester during an in-class activity. These characteristics will be discussed as will potential improvements to the scoring rubric.

Commentary by Dr. Valentin Fuster
2016;():V003T04A009. doi:10.1115/DETC2016-59661.

Engineers in the 21st century can no longer isolate themselves and must be prepared to work across disciplinary, cultural, political, and economic boundaries to meet challenges facing the US and the world. Recently, a greater emphasis is being placed on understanding social, economic and environmental impacts of engineered solutions. Undergraduate education must train students to not only solve engineering challenges that transcend disciplinary boundaries, but also communicate, transfer knowledge, and collaborate across technical and non-technical boundaries. One approach to achieving this goal is through introducing bio-inspired design in the engineering curriculum. Bio-inspired design encourages learning from nature to generate innovative designs for man-made technical challenges that are more economic, efficient and sustainable than ones conceived entirely from first principles. This paper reviews the literature pertaining to current approaches to teaching bio-inspired design in and engineering curriculum curriculum at different institutions as well as the essential competencies of the 21st century engineering. At James Madison University a Concept-Knowledge Theory instructional approach was adopted for teaching sophomore engineering design students bio-inspired design to foster many of the 21st century competencies. A pilot study was conducted to demonstrate that the 21st century competencies can be targeted and achieved. The results of study are presented, and the significance and implications of teaching bio-inspired design in an engineering curriculum are discussed.

Commentary by Dr. Valentin Fuster
2016;():V003T04A010. doi:10.1115/DETC2016-59694.

Design courses in engineering play an important role to enhance development of competencies needed by students to excel in the 21st century workplace. Problems solved by undergraduate students in engineering programs are mostly well-structured, while real world engineering problems are most likely to be ill-structured and complex. These ill-structured problems have vaguely defined goals and constraints, which demand graduates to apply the learnt knowledge beyond the understanding of fundamental concepts. To prepare and educate the future workforce for engineering workplace, we must provide them with opportunities to learn how to internalize the principles of design and to develop competencies to tackle ill-structured problems through an authentic, immersive experience that involves designing, building and testing an artifact. In this paper, we use students’ self-reported level of competencies to see how students develop competencies and how the inter-relationships among these competencies change overtime in a senior-level design course. We performed this study in Principles of Design course, during fall semester of 2014, where students addressed an ill-structured design problem. Five questionnaires were developed and administered for self-reported assessment of competencies by students. The development of competencies was tracked over time across all five surveys, followed by t-tests to identify the significant patterns of change in the developed competency level. Students showed lack of confidence in competencies related to understanding problem, requirements, concept generation and selection. Communication did not vary significantly throughout the semester. The relationships among the competencies were examined using the correlational analysis at each point and over time to identify the core competencies. Competencies related to communication, understanding problem and understanding requirements are found to be the core competencies as the development of other competencies are dependent on the level of these competencies. Recommendations have been made to modify the course in the areas of core competencies, where students lack confidence. We believe continuous improvement of student professional competencies through course modifications will help students to develop more professional competencies in a semester long design course.

Commentary by Dr. Valentin Fuster
2016;():V003T04A011. doi:10.1115/DETC2016-59767.

Design education is a large field. It is not just limited to engineering design but can also include apparel design, industrial design, graphic design, architecture, and many others. These disciplines instruct students to follow a similar design process to what is generally taught in engineering design. However, these other disciplines contain a variety of instructional techniques, class structures, and class types that are not regularly included in engineering design. While design engineers tend to get a background rich in math and science, instructing students in design can be difficult. Many of these math and science classes focus on one approach and one right answer. However, in design the answers tend to fall on a spectrum from unsatisfactory to varying levels of satisfactory to ideal and innovative solutions, all of which can be uncovered using widely varying design methods. Despite the rigidness of the mechanical engineering curriculum there are areas where the implementation of techniques used in the other design disciplines could be advantageous to help engineering design students improve students design skills, design process knowledge, and softer skills such as team communication. The research done in this paper examines how the curricula of design disciplines could influence the coursework of students focusing on the design area of mechanical engineering.

Commentary by Dr. Valentin Fuster
2016;():V003T04A012. doi:10.1115/DETC2016-60079.

Spatial thinking is paramount in engineering education, however there is a lack of reliable data on instructional strategies for developing and improving these skills. In this pilot study, we investigate the feasibility of using students’ freehand sectional view drawings to measure their initial and developing spatial skills in a semester-long engineering design graphics course. Participants included 121 junior-level students (M = 98, F = 23). Preliminary results show moderate-to-strong positive correlations between drawing accuracy and performance on two spatial thinking tests: the Purdue Spatial Visualization Test (PSVT:R), and Santa Barbara Solids Test (SBST).

Commentary by Dr. Valentin Fuster
2016;():V003T04A013. doi:10.1115/DETC2016-60250.

As Computer-Aided Design software has become more advanced, the use of hand-drawn engineering drawings has greatly diminished. This reduction has led to free-hand sketching becoming less emphasized in engineering education. While many engineering curriculums formerly included courses dedicated entirely to sketching and hand drafting, these topics are no longer addressed by most current curriculums. However, it has been observed that sketching has many benefits including improved communication in the design process, idea generation exercises, and visualizing design ideas in three-dimensional space. While isometric sketching has long been the preferred method in engineering curriculums, there are benefits of teaching perspective sketching including the creation of more realistic sketches for communication and idea generation.

This paper presents the development of a perspective-based sketching curriculum and the study of how this method compares to more traditional methods of teaching sketching to students in a freshman level engineering graphics course.

The results show that the perspective-based sketching method leads to equivalent gains in spatial visualization skills and final design self-efficacy as the traditional method of teaching hand sketching. While maintaining these skills, the new method also taught students additional skills. Through surveys and interviews, the students expressed that these skills would be useful to them in their future coursework and careers.

Commentary by Dr. Valentin Fuster
2016;():V003T04A014. doi:10.1115/DETC2016-60341.

This research paper presents the initial results of a multi-institute study comparing motivational factors between freshmen and senior mechanical engineering design students. A total of 418 freshman and senior undergraduate mechanical engineering students enrolled at the Florida Institute of Technology and the Pennsylvania State University Erie are studied. To measure motivation we utilize an adaptation of the Motivated Strategies for Learning Questionnaire (MSLQ). The MSLQ examines five factors when measuring motivation and performance. The motivational factors are test anxiety, self-efficacy, and intrinsic value while the performance factors are cognitive value, and self-regulation. Surveys are administered during both the beginning (first two weeks) and end (final two weeks) of the semester. Data is collected from freshmen and seniors through their introduction to engineering and senior design courses, respectively, at both institutes. Statistical analysis compares Likert scale student responses to demographic data. The analysis compares the motivational factors for female versus male, international versus domestic, and senior versus freshman students. Results indicate there is a change in motivational factors as students’ progress from freshman to seniors. Most of the changes are positive, such as a decrease in anxiety, increase in self-recognition, and increase in intrinsic value. Moreover, there were differences between Florida Tech and Penn State students as the makeup of both student bodies are different. This paper will compare the results and provide recommendations for improving motivational factors in freshman students to support their engineering studies and persistence in engineering.

Commentary by Dr. Valentin Fuster
2016;():V003T04A015. doi:10.1115/DETC2016-60364.

Product dissection, or the systematic disassembly of design products, has been utilized in engineering education in order to better prepare students for industry. Despite the common use of product dissection in engineering classrooms, knowledge is lacking about how effective different methods of dissection are for encouraging learning and student engineering self-efficacy. This is problematic because without this knowledge, we do not know what components of product dissection impact (positively or negatively) learning. Therefore, the purpose of this study was to identify the impact of dissection virtuality (physical and virtual), product power source (electrical and manual), and product complexity (simple and complex) on efficiency, learning, and engineering self-efficacy through a factorial experiment with 30 engineering students. The results of the study show that virtual dissection is more efficient than its physical counterpart and also maintains the same learning benefits as physical practices. These results are used to develop recommendations for the use of product dissection in education and propel future research that investigates relationships between example-based design practices and student learning outcomes.

Commentary by Dr. Valentin Fuster

13th International Conference on Design Education: Research Methods and Assessment of Design Education

2016;():V003T04A016. doi:10.1115/DETC2016-59038.

Research on expertise in design has focused primarily on understanding expert-novice differences. Although it is well established that experts perform better than novices, there is a lack of formal methods to quantify the potential impact of expertise on the quality of design outcomes. The research question addressed in this paper is: How can the impact of expertise on the quality of design solutions be quantified? Quantifying such impacts can be of particular importance in product development, recruitment processes and design competitions. We utilize an approach based on Item Response Theory (IRT) and Concept Inventories (CI) for expertise quantification. We then investigate and validate the impact of expertise on solution quality through a behavioral experiment involving a track design problem. The results highlight the usefulness of the proposed approach and provide a functional relationship between expertise and solution quality. We also observe behavioral differences between participants with varying scores on a test taken in the behavioral experiment. The proposed approach could be used in the future work to quantify learning.

Topics: Design , Performance
Commentary by Dr. Valentin Fuster
2016;():V003T04A017. doi:10.1115/DETC2016-59299.

This article presents the development, deployment, and assessment of a hands-on curriculum module for a senior-level course in component design at the Industrial and Enterprise Systems Engineering department at the University of Illinois at Urbana-Champaign. In this course students learn how to design engineering systems using gears, bearings, springs, steel structures, and other components. The course has traditionally included a semester group project where students apply their component design knowledge to a realistic design application, helping to further solidify and integrate their design knowledge. In recent years the project has centered on the design of a trailing arm automotive suspension system with components that interact in complicated ways. Students are expected to follow a rigorous engineering design process and support their design decisions with thorough engineering analysis. Until recently this project was limited to virtual analyses and design solutions; the connection between these design solutions and physical realization was an obvious gap in the project experience. This project was revised to incorporate a targeted hands-on curriculum module, which was introduced in fall 2014. Objectives of this module include helping students gain experience with the ‘media’ of engineering design, and to help students connect analytical and simulation-based studies with the corresponding physical system. The implemented module is a two-part activity in which students design a suspension system using model-based design techniques (in Matlab), followed by physical testing and further analysis using a specially built physically reconfigurable suspension testbed. This testbed allows students to test unique designs rapidly, observe real-time dynamic system performance, and to analyze the difference between simulated and physical test results. Through this activity we gauge students’ attitudes towards traditional theoretical and paper-based design activities versus the hands-on module. We also work to answer the question: “to what extent does a project-based curriculum module influence student experiences and conceptual understanding of engineering design?” through systematic student surveys designed around this new hands-on curriculum module.

Commentary by Dr. Valentin Fuster
2016;():V003T04A018. doi:10.1115/DETC2016-59597.

Each year, over 700 students take the Engineering Graphics course taught within the General Engineering Program at Clemson University. A SCALE-UP (Student-Centered Activities for Large-Enrollment Undergraduate Programs) environment is utilized to provide a highly collaborative, hands-on classroom format with a primary emphasis on learning by guided inquiry and live demonstrations rather than by traditional lecturing. One of the goals of using this format is real-time assistance and rapid feedback.

In the spring term, each class day, 400 student submit a solid model file. This presents a challenge to returning feedback before the next class period. The current grading method consists of students submitting solid model files to a course management system and awarding credit for submissions matching the mass of the presented design. However, this method does not allow students to earn partial credit based on the relative accuracy of their model. To date, instructors have been unable to reward partial credit in an automated or timely manner.

The objective of this research is to evaluate the use of shape similarity algorithms to provide decision making support while grading solid models for this engineering graphics course. The proposed method of automated grading is to use a solid model similarity algorithm and the mass properties to assess the relative similarity of each submission to a correct solid model. The distribution of grades using the proposed method is compared to the existing method’s distribution. Use of the proposed method ensures that the results from this research can be applied to other engineering graphics courses, regardless of the solid modeling software used.

Commentary by Dr. Valentin Fuster
2016;():V003T04A019. doi:10.1115/DETC2016-59757.

Assessment and feedback play an instrumental role in an individual’s learning process. Continued assistance is required to help students learn better and faster. This need is especially prominent in engineering laboratories where students must perform a wide range of tasks using different machines. One approach to understanding how students feel towards using certain machines is to assess their affective states while they use these machines. Affective state can be defined as the state of feeling an emotion. The authors of this work hypothesize that there is a correlation between students’ perceived affective states and task complexity. By adopting the Wood’s complexity model, the authors propose to assess how the correlations of perceived affective states of students change while they perform tasks of different complexity. In this study, each student performs a “hard” and an “easy” task on the same machine. Each student is given the same tasks using the same materials. Knowledge gained from testing this hypothesis will provide a fundamental understanding of the tasks that negatively impact students’ affective states and risk them potentially dropping out of STEM tracks, and the tasks that positively impact students’ affective states and encourage them to engage in more STEM-related activities. A case study involving 22 students using a power saw machine is conducted. Perceived affective states and completion time were collected. It was found that task complexity has an effect on subjects’ affective states. In addition, we observed some weak correlation between some of the perceived affective states and laboratory task performance. The distribution of correlation between affective states may change as the tasks change. With the knowledge of the relationship between task complexity and affective states, there is the potential to predict students’ affective states before starting a given engineering task.

Commentary by Dr. Valentin Fuster

13th International Conference on Design Education: Short Papers: Innovations in Design Education

2016;():V003T04A020. doi:10.1115/DETC2016-59090.

In August 2013, the Purdue University President and Board of Trustees designated the transformation of the College of Technology into the Purdue Polytechnic Institute as one of Purdue’s “Big Moves”. This transformation requires changes of enormous breadth and depth for everyone in the college. Now, almost half-way through the transformation, milestones and expectations continue to be met. However, much work is still to be done to fully execute a successful transformation. The transformation continues to allow faculty extraordinary opportunities to revise many parts of the college, including curricula, instruction methods, learning spaces, etc. A key characteristic of the transformation is creating learning environments that are student-centered with innovative instruction techniques.

TECH 120 – “Design Thinking in Technology”, is a freshman level survey course designed to develop a student’s perspective and enhance their skills in living and working in a technological society while introducing them to the College of Technology — now Purdue Polytechnic. Prior to the fall 2015 semester, Purdue Polytechnic New Albany decided to redesign portions of their TECH 120 course. The aim was to improve team project-based learning opportunities while incorporating modernized teaching methods. With a fresh set of eyes and collaboration between new and tenured faculty the projects, lectures, and assessments were all analyzed looking for areas for higher level of innovation and creativity. The aim for the overall effort was to increase student success rate (i.e. successful completion of assigned project tasks) while improving the alignment with elements of the transformation.

In past semesters, the course consisted of a mixture of traditional instructor-led lectures and a series of team projects. Each individual project part was intended to build upon each other while promoting the successful completion of a much larger final task. At the core of each project was LEGO® MINDSTORMS® NXT. The second generation set in the MINDSTORMS series is a programmable robotics kit that is based on robotics technology similar to that used in industry today. Each group (3–4 students) were given their own kit at the beginning of the semester. The final project statement was to design and build an autonomous robot which could identify and follow a light source attached to an instructor’s robot, which would be driven around a room. This task proved to be difficult and had a low success rate.

The new project is to design and build a robot that autonomously draws the initials (first and last name) of each team member within an assigned writing zone on a poster. The constant and open collaboration between the two TECH 120 instructors and the incorporation of student input proved to be important during the redesign. The success rate at the end of the semester increased. From course surveys, data also shows that students’ enjoyment and interest in the final project increased.

This short paper will describe the introduction to a team project-based activity in a polytechnic setting which uses modernized teaching methods. Preliminary findings and observations will be presented.

Topics: Design
Commentary by Dr. Valentin Fuster
2016;():V003T04A021. doi:10.1115/DETC2016-59701.

There is a need to improve the innovation and entrepreneurship capacity of engineering design students before graduation, as innovation and entrepreneurship are drivers of economic growth. This paper presents the alignment of existing courses within a university system, mainly Design Thinking (Engineering) and Consumer Behavior (Marketing), with the purpose of developing technology-based entrepreneurship efforts that directly impact a society in need of economic development. Students from each course were presented with six current problems being faced by society, for them to work on in groups. The experience of having interdisciplinary teams working together to achieve a common goal is documented. Also, in order to measure the impact of the courses on the students, a survey of innovation self-efficacy was given to the students at the beginning and at the end of each semester. The results and implications for engineering design education are discussed.

Commentary by Dr. Valentin Fuster
2016;():V003T04A022. doi:10.1115/DETC2016-60288.

To address the grand challenge of the severe shortage of qualified engineering workforce and equally important educators, engineering and education departments at Manhattan College created a holistic program called Engineering Scholars Training and Retention (STAR) program. Engineering STAR program created a collaboration among undergraduate education and engineering majors, the professors who teach them and current STEM teachers and their students in local urban middle and high schools.

We developed three new academic programs (engineering education minor and certificate programs for both undergraduate and graduate engineering and education majors) to support engineering and education students who are passionate about promoting engineering for 6–12 grade students and become qualified and competent engineering educators.

In addition, through partnership with local middle/high schools we developed an engineering ambassadors’ program where students from engineering and education majors develop hands-on design projects and present them to middle/high school students to encourage and inspire more students to study engineering.

Next, we engaged in a professional development program to support current STEM teachers to develop skills in engineering and increase the number of teachers who possess the pedagogical content knowledge to prepare students to be successful in engineering fields.

All three aspects of the STAR program employees engineering design projects to introduce engineering to students and teachers. This integrative model could serve initially as a template to design such programs.

Commentary by Dr. Valentin Fuster
2016;():V003T04A023. doi:10.1115/DETC2016-60358.

Many K-12 students, and perhaps even some of their teachers, lack clear understanding of the significance or roles of an engineer [4, 13]. With the ever-growing integration of technology in our society, there is a need to establish a stronger foundation of STEM education, specifically ‘E’: engineering. Several research groups believe and have published data supporting the idea that minimal exposure of engineering at a young age may lead to the absence of motivation by students to consider engineering as a future career [14, 15]. In contrast, studies have also shown that exposing students to engineering concepts early in their academic careers could influence them to seriously consider engineering [28]. In this study, hands-on outreach events were held for students at local K-12 schools to expose and share knowledge about the importance of engineering, careers engineers enter into, and examples of problems engineers work to solve daily. Students were given the opportunity to reverse engineer various small home appliances to learn about the components and how those components collectively help complete a system function. These appliances were gender neutral, and included power drills, hair dryers, coffee makers and more. To engage their minds further, students were tasked with redesigning the product with proposed improvements to increase the product’s overall functionality and/or efficiency. The students were surveyed with a questionnaire to gauge their interest in engineering. This data was analyzed and it was found that though the students viewed engineering as fun and exciting, it did not correlate to their desire to pursue it as a career. Additionally, the known gender gap that exists in engineering today was reconfirmed with this study.

Commentary by Dr. Valentin Fuster

9th Frontiers in Biomedical Devices: Computational Modeling and Simulation

2016;():V003T11A001. doi:10.1115/DETC2016-59019.

The biomechanical behavior of brain tissue is needed for predicting the traumatic brain injury (TBI). Each year over 1.5 million people sustain a TBI in the United States. The appropriate coefficients for modeling the injury prediction can be evaluated using experimental data. In the present paper, using an experimental setup on bovine brain tissue, unconfined compression tests at quasi-static strain rates of Display Formulaε. = 0.0004s−1, 0.008s−1 and 0.4s−1 combined with a stress relaxation test under unconfined uniaxial compression with Display Formulaε. = 0.67s−1 ramp rate are performed. The fitted visco-hyperelastic parameters were utilized by using obtained stress-strain curves. The finite element analysis (FEA) is validated using experimental data.

Commentary by Dr. Valentin Fuster
2016;():V003T11A002. doi:10.1115/DETC2016-59021.

Traumatic brain injury (TBI) has long been known as one of the most anonymous reasons for death around the world. This phenomenon has been under study for many years and yet it remains a question due to physiological, geometrical and computational complexity. Although the modeling facilities for soft tissue have improved, the precise CT-imaging of human head has revealed novel details of the brain, skull and meninges. In this study a 3D human head including the brain, skull, and meninges is modeled using CT-scan and MRI data of a 30-year old human. This model is named “Sharif University of Technology Head Trauma Model (SUTHTM)”. By validating SUTHTM, the model is then used to study the effect of +Gz acceleration on the human brain. Damage threshold based on loss of consciousness in terms of acceleration and time duration is developed using Maximum Brain Pressure criteria. Results revealed that the Max. Brain Pressure ≥3.1 are representation of loss of consciousness. 3D domains for the loss of consciousness are based on Max. Brain Pressure is developed.

Commentary by Dr. Valentin Fuster
2016;():V003T11A003. doi:10.1115/DETC2016-59433.

Recently researches have reported the ocular structural and functional changes observed in astronauts after long-duration space flight, which includes optic disk edema, globe flattening, choroidal folds, hyperopic shifts and reduction of near visual acuity. This syndrome, which is called the Visual Impairment/Intracranial Pressure (VIIP) Syndrome, is reported due to the alterations of translaminar pressure and some other factors (concentration of CO2, genotype, B-vitamin status, androgens, etc.) in microgravity or in space station. On account of the shortage of measurement and limit of sample size in space experiments, the study of VIIP Syndrome was difficult to make progress. In this research, numerical analysis combined with animal experiment were performed. In the animal experiment, hindlimb suspension (HLS) model was used to simulate the cephalic liquid shifts of Sprague-Dawley (SD) rats in microgravity, as well as fundus photography and optical coherence tomography (OCT) were executed to detect the ocular structural changes. For both the experimental group and the control group, the illumination, temperature and feeding were strictly controlled, well the watering was unrestricted, during the long-term hinlimb suspension. The ocular structural changes and the physiological index including weight and intraocular pressure (IOP) were evaluated. A numerical model of eye was established, then finite element analysis was performed to study the biomechanical response of ocular structure due to the changes of translaminar pressure. We observed that the changes of the ocular structure in rats after the long-term hindlimb suspension were consistent with the finite element simulation results. The findings in this research showed the significance of animal experiment and numerical analysis for the study of VIIP Syndrome.

Commentary by Dr. Valentin Fuster
2016;():V003T11A004. doi:10.1115/DETC2016-59455.

The importance of physiotherapy is becoming more significant with the increasing number of countries with aging populations. Thus, the education of physiotherapists is a crucial concern in many countries. Information and communications technologies, such as motion capture systems, have been introduced to sophisticate the training methods used in physiotherapy. However, the methods employed in most training schools for physiotherapists and occupational therapists remain dependent on more conventional materials. These materials include conventional textbooks with samples of traditional gait motion photographs and video archives of patients’ walking motion. Actual on-site clinical training is also utilized in current physiotherapy education programs. The present paper addresses an application of previously developed digital human model called kinematic digital human (KDH) to physiotherapy education with a focus on improving students’ understanding of the gait motion of disabled patients. KDH models for use in physiotherapy were constructed based on Rancho Los Amigos National Rehabilitation Center terminology, which is considered the preferred standard among clinicians. The developed KDH models were employed to allow the three-dimensional visualization of the gait motion of a hemiplegic patient.

Commentary by Dr. Valentin Fuster
2016;():V003T11A005. doi:10.1115/DETC2016-59934.

The objective of this research is to model the geometric variability of the glenoid (the “socket” component of the “ball and socket” connection of the shoulder joint) of the scapula. The model must capture the observed variability with sufficient resolution such that it informs operative and design decisions. This required the quantification of variability in landmark locations and relevant bone geometry. Landmarks were placed on the existing glenoid meshes, such that they provided enough information to represent the geometry, while being consistent across each glenoid. Additionally, the surface geometry of the glenoid vault was modeled. This required the application of existing mathematical and statistical modeling approaches, including geometric fitting, radial basis functions, and principal component analysis. The landmark identification process represented the glenoid in new manner. The work was validated against existing approaches and CT scans from 42 patients.

A range of information on shoulder geometries can assist with preoperative planning, as well as implant design, for Total Shoulder Arthroplasty (TSA). Principal component analysis (PCA) was used to quantify the variability of shape across the glenoid landmarks, and synthesize new glenoid models. The process of creation of these shoulder geometries may possibly be useful for the study of other joints. The models created will help surgeons and engineers to understand the effects of osteoarthritis on bone geometry, as well as the range of variability present in healthy shoulders.

Topics: Modeling , Geometry
Commentary by Dr. Valentin Fuster
2016;():V003T11A006. doi:10.1115/DETC2016-60408.

Majority of wheelchair users experience upper-body muscular weakness, resulting from neuromuscular diseases, which limit their ability to perform common activities of daily living. A Wheelchair Mounted Robotic Arm (WMRA) will assist these individuals to eat, drink, and move objects as needed. This paper presents the design of a new WMRA as well as the analysis of its function. The design is side-mounted onto either a normal or power wheelchair, and incorporates a slim profile to allow ease of passage through doorways and be otherwise unobtrusive. The arm is easily removable, with assistance, for storage or travel. The mechanical design utilizes a belt and pulley system for remote actuation of each joint, driven by DC Gearmotors located in the base of the arm. This helps to shift the weight closer to the wheelchair and to maintain the required speed, torque and inertia while actively driving each joint of the robot. The end-effector is a unique design, intended to have the adaptability to securely lift a large variety of objects. Grasping simulations were performed on several standard objects which might be encountered daily. Structural, kinematic and workspace analyses are conducted, and results confirm that the designed WMRA is rated to lift a 4 kg payload, while also having a reach of 1.3 meters long radius.

Commentary by Dr. Valentin Fuster
2016;():V003T11A007. doi:10.1115/DETC2016-60444.

In this paper, we investigate the effect of mechanical deformation during original impact on the propagation of bleeds during traumatic brain injury (TBI). For this purpose, we have developed a numerical framework that considers Magnetic Resonance Images (MRI) of a rat subjected to TBI modelled using controlled cortical impact (CCI). Using the MRI images of first day of impact a solid model of brain is developed and strains during impact are estimated using the finite element tool LSDyna. It was observed that the actual propagation of blood obtained from day 14 MRI data closely resembles the one developed by solving a time dependent advection equation with advection rates proportional to the strain estimates during impact from LSDyna. This numerical framework holds promise that with proper calibration and validation it can be used to predict the possible propagation of blood post-impact and therefore may be used to inform treatment protocols for such patients.

Commentary by Dr. Valentin Fuster
2016;():V003T11A008. doi:10.1115/DETC2016-60456.

Having the ability to study the activity of single neurons will facilitate studies in many areas including cognitive sciences and brain computer interface applications. Due to the fact that every neuron has it’s own unique spike waveform, by applying spike-sorting methods, one can separate neurons based on their associated spike. Spike sorting is an unsupervised learning problem in the realm of data mining and machine learning. In this study, a new method that will improve the accuracy of spike sorting in comparison to existing methods has been introduced. This method, which is named Multi Cluster Feature Selection (MCFS), will designate a reduced number of features from the original data set that will best differentiate the existing clusters through solving a Lasso optimization problem. MCFS, was also applied to data obtained from multi-channel recordings on a rat’s brain. With MCFS, each channel was studied and neurons in each channel were sorted with an improved rate in comparison to conventional methods such as PCA.

Commentary by Dr. Valentin Fuster

9th Frontiers in Biomedical Devices: General Biomedical Devices

2016;():V003T11A009. doi:10.1115/DETC2016-59199.

Oxygen concentration devices currently on the market have many shortcomings. They are bulky and difficult to carry. They alter a patient’s outward image with a visual mark of disability. They do not change oxygen delivery in any way to adjust to the patient’s health. They also lack indicators to help the patient decide when to begin or end a therapy session. Some patient’s decide not to take oxygen therapy as a result of these shortcomings. Those that use these devices may receive over oxygenation or under oxygenation due to the mentioned pitfalls. Any of the shortcomings described can be life threatening to the patient.

The present innovation is a proposed system for oxygen delivery that adjusts flowrate based on the patient health and requires no user input to begin or end a therapy session. This paper presents a unique wearable device design for delivering oxygen in a pressure based concentration system.

Commentary by Dr. Valentin Fuster
2016;():V003T11A010. doi:10.1115/DETC2016-60180.

In this paper, we present a robust post processing method to improve the accuracy of kinematics information of human walking gait obtained from the Kinect sensor to be used for home-based gait analysis purposes. The accuracy of raw skeleton tracking data provided by Kinect suffers from a considerable level of uncertainty that compromises any reliable motion analysis. To address this issue, we have developed a comprehensive framework that reconstructs the joint trajectories from the Kinect’s uncertain measurements. The proposed algorithm detects valid motion periods as well as valid segments that represent starting and ending points of fully observed walking gait cycles. It then estimate the skeleton parameters based on the data within these valid periods. The variations of the estimated parameters is significantly reduced when only the data within valid periods are used. Moreover, by considering human motor control principles, the orientation of each limb is filtered through a 5th order polynomial fitting algorithm (Savitzky-Golay). This process removes sudden jumps/deviations which are inconsistent with human motor control. This fitting process along with the estimated skeleton parameters as geometrical constraints are used to reconstruct the joint trajectories. The experimental results demonstrate higher repeatability and less dispersion of the reconstructed joint trajectories compared to the raw skeleton information.

Topics: Kinematics
Commentary by Dr. Valentin Fuster
2016;():V003T11A011. doi:10.1115/DETC2016-60487.

This paper presents a fused metric for the assessment of physical workload that can improve fatigue detection using a statistical visualization approach. The goal for considering this combined metric is to concisely reduce the number of variables acquired from multiple sensors. The sensor system gathers data from a heart rate monitor and accelerometers placed at different locations on the body including trunk, wrist, hip and ankle. Two common manufacturing tasks of manual material handling and small parts assembly were tested. Statistical process control was used to monitor the metrics for the workload state of the human body. A cumulative sum (CUSUM) statistical analysis was applied to each of the single metrics and the combined metric of heart rate reserve and acceleration (HRR*ACC). The sensor data were transformed to linear profiles by using the CUSUM plot, which can be monitored by profile monitoring techniques. A significant variation between the lifting replications was observed for the combined metric in comparison to the single metrics, which is an important factor in selecting a fused metric. The results show that the proposed approach can improve the ability to detect different states (i.e., fatigue vs. non-fatigued) in the human body.

Commentary by Dr. Valentin Fuster

9th Frontiers in Biomedical Devices: Implantable and Wearable Devices

2016;():V003T11A012. doi:10.1115/DETC2016-60137.

This paper presents an analysis of a mechanism which aims to reduce the energy consumption during locomotion. The mechanism is based on a linear extension spring positioned in parallel with the Achilles tendon. The tension of the spring is regulated by a ratchet-pawl mechanism that engages during the flat foot phase of locomotion. The tension of the spring is used in parallel to the calf muscles to slow down the velocity of the body before the double support phase of locomotion thus avoiding the energy to be dissipated by the muscles. The release of the ratchet avoids reinjection of the energy stored in the spring back into the system. We find that this process is theoretically sound and we provide a verification of the contact stresses acting on the release mechanism.

Commentary by Dr. Valentin Fuster
2016;():V003T11A013. doi:10.1115/DETC2016-60237.

This paper presents the design and control of a human prosthetic hand with an active palm roll joint. An active palm roll to a prosthetic hand will add a new degree-of-freedom, which can maximize the functionality and capability of performing complex tasks. The palm roll combined with the thumb allows the finger tips to touch one another and pinching to become a possible task for the user. In addition to maximizing the functionality of the hand, the inclusion of an active palm joint in the design provides a useful function for the design of prosthetics for children and the elderly who do not have enough upper arm strength to grasp objects firmly in their hand. The kinematics and workspace analyses of the pinky fingertips with the active palm joint and the thumb are also conducted in this study. With the added palm joint, the interaction of the workspace of the pinky fingertip and the thumb-tip is maximized, which allows grasping and manipulating different sizes and shapes of an object. Experiments are conducted to demonstrate the use of the active palm joint in grasping of objects.

Commentary by Dr. Valentin Fuster
2016;():V003T11A014. doi:10.1115/DETC2016-60512.

Piezoelectric materials are commonly found in many devices, but their usage is limited by the low strain and high stiffness of the material. This prevents their use in “soft” applications, such as compliant actuators for haptic feedback devices and wearable technology. The actuation dynamics of a ferro-electric relaxor terpolymer, a type of soft and high strain electroactive polymer (EAP), are examined. This paper studies the unimorph actuator via a linearized time-domain model and experiments to validate the model include step response and frequency response of tip displacement.

Commentary by Dr. Valentin Fuster
2016;():V003T11A015. doi:10.1115/DETC2016-60573.

This paper investigates energy harvesting from arterial blood pressure via the piezoelectric effect for the purpose of powering embedded micro-sensors in the brain. Blood flow is highly dynamic and arterial blood pressure varies, in the average human blood vessel, from 120 mm of Hg to 80 mm of Hg and we look at transduction of this pressure variation to electric energy via the piezoelectric effect. We propose two different geometries for this purpose. Initially, we look at the energy harvested by a cylinder, coated with PVDF (Polyvinylidene fluoride) patches, placed inside an artery acted upon by blood pressure. The arrangement is similar to that of a stent which is a cylinder placed in veins and arteries to prevent obstruction in blood flow. The governing equations of the harvester are obtained using Hamilton’s principle. Pressure acting in arteries is radially directed and this is used to simplify the governing equations. Specifically, radial pressure directed on the inner wall of the cylinder is assumed to excite only the radial breathing mode of vibration. Using this, the transfer function relating pressure to the induced voltage across the surface of the harvester is derived and the power harvested by the cylindrical harvester is obtained for different shunt resistances.

However, the natural frequency of the radial breathing mode (RBM) is found to be very high and the harvested power at the frequencies of interest (3 Hz – 20 Hz) is very low. To decrease the natural frequency, we propose a novel streaked cylinder design that involves cutting the cylinder along the length, transforming it to a curved beam with an opening angle of 360 deg.. The governing equations corresponding to a circular curved beam, with PVDF patches on top and bottom surfaces, are derived using Hamilton’s principle and modal analysis is used to obtain the transfer function relating radial pressure to induced voltage. We validate the derived transfer function by evaluating the harvested power for a beam with very large radius of curvature; in which case, the curved beam becomes a straight beam and the harvested power is compared with the same for a straight beam (which exists in the literature). Further, we conduct design analyses and obtain the power as the geometric parameters of the harvester are varied for the purpose of optimizing the dimensions of harvester for maximal power generation. The power harvested by the harvester, at lower frequencies is deemed to be satisfactory.

Commentary by Dr. Valentin Fuster

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