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The current test methods are insufficient to evaluate and ensure the safety and reliability of vehicle system for all possible dynamic situations including the worst cases such as rollover, spin-out and so on. Although the known NHTSA J-turn and Fish-hook steering maneuvers are applied for the vehicle performance assessment, they are not enough to predict other possible worst case scenarios. Therefore, it is crucial to search for the various worst cases including the existing severe steering maneuvers. This paper includes the procedure to search for other useful worst case based upon the existing worst case scenarios in terms of rollover and its application in simulation basis. The human steering angle is selected as a design variable and optimized to maximize the index function to be expressed in terms of vehicle roll angle. The obtained scenarios were enough to generate the worse cases than NHTSA ones.

Ten mold-in-color black polymers were evaluated for exterior weathering in an attempt to improve the specifications for exterior mold-in-color plastics to meet five year durability for a 95th percentile sunbelt customer. Four different weathering methods were utilized including Arizona exposure, Florida exposure, and Xenon arc exposures per the GMNA and the GM Europe methods. Colorfastness, gloss retention and other material property changes due to weathering were measured and analyzed against two GM durability standards. For the appearance attributes, correlations between actual exposure and accelerated exposure were attempted. Test results before and after polishing were also analyzed. Finally, in addition to comparing the performance of the ten polymers, the four weathering methods are compared and discussed with recommendations for the preferred testing regimen.

Warpage is the distortion induced by inhomogeneous shrinkage during injection molding of plastic parts. Uncontrolled warpage will result in dimensional instability and bring a lot of challenges to the mold design and part assembly. Current commercial simulation software for injection molding cannot provide consistently accurate warpage prediction, especially for semi-crystalline thermoplastics. In this study, the root cause of inconsistency in warpage prediction has been investigated by using injection molded polypropylene plaques with a wide range of process conditions. The warpage of injection molded plaques are measured and compared to the numerical predictions from Moldex3D. The study shows that with considering cooling rate effect on crystallization kinetics and using of the improved material model for residual stress calculations, good agreements are obtained between experiment and simulation results.

Digital human models (DHM) are now widely used to assess worker tasks as part of manufacturing simulation. With current DHM software, the simulation engineer or ergonomist usually makes a manual estimate of the likely worker standing location with respect to the work task. In a small number of cases, the worker standing location is determined through physical testing with one or a few workers. Motion capture technology is sometimes used to aid in quantitative analysis of the resulting posture. Previous research has demonstrated the sensitivity of work task assessment using DHM to the accuracy of the posture prediction. This paper expands on that work by demonstrating the need for a method and model to accurately predict worker standing location. The effect of standing location on work task posture and the resulting assessment is documented through three case studies using the Siemens Jack DHM software.

BACKGROUND: Detailed fatal injury data following fatal motor vehicle crashes (MVC) are necessary to improve occupant safety and promote injury prevention. Autopsy remains the principle source of detailed fatal injury data. However, procedure rates are declining due to a range of technical, ethical and religious concerns. Postmortem computed tomography (PMCT) is a potential alternative or adjunct to autopsy which is increasingly used by forensic researchers. However, there are only limited data regarding the utility of PMCT for analysis of fatal MVC injuries. METHODS: We performed whole body PMCT, autopsy and complete crash reconstruction on 3 subjects fatally injured in MVC in a single county in Michigan. All injuries detected by either PMCT or autopsy were coded using the Abbreviated Injury Scale (AIS). Severe injuries, defined as AIS 3 or higher (AIS 3+), were tallied for each forensic procedure to allow a comparison of relative diagnostic performance.

Predicting the vibration of a motor gearbox assembly driven by a PWM inverter in the early stages of development is demanding because the assembly is one of the dominant noise sources of electric vehicles (EVs). In this paper, we propose a simulation model that can predict the transient vibration excited by gear meshing, reaction force from the mount, and electromagnetic forces including the carrier frequency component of the inverter up to 10 kHz. By utilizing the techniques of structural model reduction and state space modeling, the proposed model can predict the vibration of assembly in the operating condition with a system level EV simulator. A verification test was conducted to compare the simulation results with the running test results of the EV.

Liver injuries can be significant in vehicle crashes. In this study, the liver anatomy was quantified in both adult and pediatric populations as a function of gender and age. Five anatomical liver measurements were determined using CT scans of 260 normal livers. These measurements include the area and volume, and the length, width, and girth of the liver (IRB HUM00041441). To characterize geometrical shape, an inscribed sphere and circumscribed ellipsoid were fitted on the measurements. In the pediatric population the liver area and volume continuously increased with age. When normalized by patient weight, volume measurements show a decrease in volume with age, suggesting that the liver occupies a smaller proportion of the body with age. In the adult population, liver measurements varied with gender. The superior and inferior locations of the liver were also recorded with respect to the spine. The lower portion was at the L3 in small children and at L2 as children approached puberty.

Quasi-static tensile properties of TRIP590 steels from three different manufacturers were investigated using digital image correlation (DIC). The focus was on the post-uniform elongation behavior which can be very different for steels of the same grade owing to different manufacturing processes. Miniature tensile specimens, cut at 0°, 45°, and 90° relative to the rolling direction, were strained to failure in an instrumented tensile stage. True stress-true strain curves were computed from digital strain gages superimposed on digital images captured from one gage section surface during tensile deformation. Microstructural phases in undeformed and fracture specimens were identified with optical microscopy using the color tint etching process. Fracture surface analyses conducted with scanning electron microscopy and energy dispersive spectroscopy were used to investigate microvoids and inclusions in all materials.

Tanker trucks are commonly used for transporting liquid material including chemical and petroleum products. On the one hand, tanker trucks are susceptible to rollover accidents due to the high center of gravity when they are loaded and due to the liquid sloshing effects when the tank is partially filled. On the other hand, tanker truck rollover accidents are among the most dangerous vehicle crashes, frequently resulting in serious to fatal driver injuries and significant property damage, because the liquid cargo is often hazardous and flammable. Therefore, effective schemes for tanker truck rollover avoidance are highly desirable and can bring a considerable amount of societal benefit. Yet, the development of such schemes is challenging, as tanker trucks can operate in various environments and be affected by manufacturing variability, aging, degradation, etc. This paper considers the use of Learning Reference Governor (LRG) for tanker truck rollover avoidance.

Morphological features of voids were characterized for T300/924 12-ply and 16-ply composite laminates at different porosity levels through the implementation of a digital microscopy (DM) image analysis technique. The composite laminates were fabricated through compression molding. Compression pressures of 0.1MPa, 0.3MPa, and 0.5MPa were selected to obtain composite plaques at different porosity levels. Tension-tension fatigue tests at load ratio R=0.1 for composite laminates at different void levels were conducted, and the dynamic stiffness degradation during the tests was monitored. Fatigue mechanisms were then discussed based on scanning electron microscope (SEM) images of the fatigue fracture surfaces. The test results showed that the presence of voids in the matrix has detrimental effects on the fatigue resistance of the material, depending on the applied load level.

Among the most important finishing structures of a vehicle interior, the door trim panels reduce external noises, present ergonomic concepts generating comfort, improve appearance, and provide objects storage, knobs and buttons. The panels usually composed of several molded parts (trim, armrest, etc.) connected to each other also have structural function as support closing loads, protect occupants of door internal mechanisms, energy absorption in side impacts and resist misuse conditions. Therefore, these trims usually made of polymeric materials must to present good structural integrity, demanding appropriate connections between components to have good load distribution. The connections between parts can be made using bolts, interference fits (like self-locking), welding tubular plastic towers (heat stakes), or clips (such as snap fits) and last two are the most common due to be cheap and with good retention.

A multi-body dynamics model of the U.S. Army3s High Mobility Multi-purpose Wheeled Vehicle (HMMWV) has been created using commercial software (ADAMS) to simulate and analyze the vehicle3s rollover behavior. However, manual operation of such simulation and analysis for design purposes is prohibitively expensive and time consuming, limiting the engineers3 ability to utilize the model fully and extract from it useful design information in a timely, cost-effective manner. To address this challenge, a commercial system integration and optimization software (OPTIMUS) is utilized in order to automate the simulation processes and to enable the more complex uncertainty-based analysis of the HMMWV rollover behavior under a variety of external conditions. Challenges involved in integrating the software are highlighted and remedies are discussed. Rollover analysis results from using the integrated model and automated simulation are also presented.

Sintered parts mechanical properties are very sensitive to final density, which inevitable cause an enormous density gradient in the green part coming from the compaction process strategy. The current experimental method to assess green density occurs mainly in set up by cutting the green parts in pieces and measuring its average density in a balance using Archimedes principle. Simulation is the more accurate method to verify gradient density and the main benefit would be the correlation with the critical region in terms of stresses obtained by FEA and try to pursue the optimization process. This paper shows a case study of a part that had your fatigue limit improved 1000% using compaction process simulation for better optimization.

Efficient methods for simulating operators performing part handling tasks in manufacturing plants are needed. The simulation of part handling motions is an important step towards the implementation of virtual manufacturing for the purpose of improving worker productivity and reducing injuries in the workplace. However, industrial assembly tasks are often complex and involve multiple interactions between workers and their environment. The purpose of this paper is to present a series of industrial simulations using the Human Motion Simulation Framework developed at the University of Michigan. Three automotive assembly operations spanning scenarios, such as small and large parts, tool use, walking, re-grasping, reaching inside a vehicle, etc. were selected.

This paper presents a simplified approach for formability simulation of automotive body structural sections in the early design stage of vehicle development process. Plane strain approach is investigated for its applicability and accuracy by comparing the analytical results with the measured results of automotive body side panel. The plane strain approach was tried based on the fact that for a certain section location of a stamped panel, the minor strains are relatively small and negligible compared to the major strains. The state of plane strain can be induced mainly through symmetry and applied boundary conditions. This approach is both cost effective and time saving for analyzing sheet metal formability in early vehicle development stage, since only few sections of the entire panel need be analyzed.

Lap-shoulder belt effectiveness has been indicated by many authors, however there is minimal information on the more severe injuries to lap-shoulder belted car occupants. This paper presents details of 15 lap-shoulder belted occupants in frontal collisions and 24 lap-shoulder belted occupants in side impact collisions. Case descriptions of these crashes are presented, each including vehicle, environmental and injury details.

This presentation is an assessment of the turbulence-stress scale-similarity in an IC engine, which is used for modeling subgrid dissipation in LES. Residual stresses and Leonard stresses were computed after applying progressively smaller spatial filters to measured and simulated velocity distributions. The velocity was measured in the TCC-II engine using planar and stereo PIV taken in three different planes and with three different spatial resolutions, thus yielding two and three velocity components, respectively. Comparisons are made between the stresses computed from the measured velocity and stress computed from the LES resolved-scale velocity from an LES simulation. The results present the degree of similarity between the residual stresses and the Leonard stresses at adjacent scales. The specified filters are systematically reduced in size to the resolution limits of the measurements and simulation.

In this paper, a simulation-based dynamic rollover evaluation procedure is described. This work is based on the worst-case methodology developed at the University of Michigan, and is the result of a collaborated research project between the University of Michigan and TRW Inc. The target vehicle studied in this paper is a large production volume SUV. This vehicle is equipped with a production-intent TRW Vehicle Stability Control (VSC) system. The main goals of this paper are to (i) study the rollover propensity of this SUV, as influenced by vehicle and environment parameters such as vehicle speed, road condition, etc.; and (ii) investigate whether, and by how much, does the VSC system influence the rollover propensity of this SUV. The modeling, evaluation procedure, and preliminary evaluation results are reported.

Electric Power Assisted Steering (EPAS) is widely adopted in modern vehicles to reduce steering effort. It is probable that some EPAS systems will experience a shutdown due to reliability issues stemming from electrical and/or electronic components. In the event of EPAS failure, power assist becomes unavailable and the steering system reverts to a fully manual state, leading to excessive steering torque demands from the driver to maneuver the vehicle at lower speeds, i.e., under 30 mph. This situation has resulted in dozens of reported crashes and several OEM safety recalls in the past few years. Inspired by recent work which utilizes independent driving torque of in-wheel-motor vehicles to reduce steering torque, this paper proposes the use of Differential Braking Assisted Steering (DBAS) to alleviate steep increases in steering torque upon EPAS failure. DBAS requires software upgrades with minimal hardware modification to EPAS, which is preferable for a backup system.

In June 1997, the Vehicle Recycling Partnership (VRP) and the American Plastics Council (APC) asked MBA Polymers to conduct a study to determine the technical and economic feasibility of recovering metals and plastics from end-of-life radiator end caps (RECs). The VRP worked with the Institute of Scrap Recycling Industries (ISRI) to obtain samples of RECs from two metal recycling companies, SimsMetal America and Aaron Metals. MBA performed its standard Recyclability Assessment on the materials, which included a detailed density and material characterization study and an actual processing study using its pilot processing line. It was found that the polyamide from RECs could be recovered in reasonably high yield and purity using tight density separations. The recycling of the REC samples used for this study generated about 40% nonferrous metal, 19% mixed ferrous and nonferrous metal and about 20% polyamide flakes.