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Magazine
2014-04-01
Methodology developed for safer hood design The methodology enables material selection and design optimization of energy absorbers for pedestrian protection based on a simple laboratory test and FE model, eliminating the need for extensive vehicle testing. Developing a winning formula It's been 20 years since the University of Michigan won a Formula SAE championship. Sick of getting smoked in recent years by top teams from Germany and the U.S., MRacing is going "big aero" for a better crack at the 2014 crown.
Technical Paper
2014-04-01
Parul Goyal, Feng Liang, Olof Oberg
Abstract The aim of the paper is to describe how Volvo Construction Equipment uses a virtual product development process to analyze potential risks, find root causes and optimize future product development. A model based method is used to analyze a potential risk in the design of Wheel Loader transmissions. The risk was recognized from failure mode and effect analysis (FMEA), and a simulation model using AMESim modeling tool was developed to analyze the behavior of the new design. Together with test rig result, it is proved that the model based method gives a considerably accurate prediction of the system behavior. By using the model based approach, lead time for development process is reduced and important feedbacks from simulation model are obtained on early stage of the development. This paper further presents the use of the simulation model as a tool to predict the potential risks in the extreme operating conditions, which are difficult to test on the vehicle test bench.
Technical Paper
2014-04-01
Thomas Juergen Boehme, Tobias Sehnke, Matthias Schultalbers, Torsten Jeinsch
Abstract In this paper an energy management is proposed which is optimal to certain driving scenarios which can be clustered into freeway, rural and urban situations. This strategy is non-predictive but uses information about the current driving situation provided by modern navigation systems to identify the current road type. Based on this information a set of simplified optimal control problems are solved offline via an indirect shooting algorithm. By relaxation of the problem formulation, the solutions of these optimal control problems can be stored into easily implementable maps. The energy management control is then determined from these maps during vehicle operation using the current road type, the vehicle speed and the required wheel-torque. The strategy is implemented in a dSPACE MicroAutoBox and validated on a near mass-production vehicle. The proposed methodology has shown fuel savings on a real world drive cycle. Additionally, robustness aspects have been considered in a MATLAB/Simulink based simulation environment.
Technical Paper
2014-04-01
Horst Lanzerath, Niels Pasligh
Abstract Structural adhesives are widely used across the automotive industry for several reasons like scale-up of structural performance and enabling multi-material and lightweight designs. Development engineers know in general about the effects of adding adhesive to a spot-welded structure, but they want to quantify the benefit of adding adhesives on weight reduction or structural performance. A very efficient way is to do that by applying analytical tools. But, in most of the relevant non-linear load cases the classical lightweight theory can only help to get a basic understanding of the mechanics. For more complex load cases like full car crash simulations, the Finite Element Method (FEM) with explicit time integration is being applied to the vehicle development process. In order to understand the benefit of adding adhesives to a body structure upfront, new FEM simulation tools need to be established, which must be predictive and efficient. Therefore new FEM crash methods for structural adhesives have been investigated and validated with the help of test results.
Technical Paper
2014-04-01
Youmei Zhao
The Hybrid III 50th male dummy is widely used in front impact crash tests in the world to evaluate the vehicle safety performance. The chest impact calibration test should be conducted after certain amount of crash tests to ensure that the dummy has the right performance during the crash tests. The impact velocity in the current chest calibration tests is 6.71 m/s and the chest displacement corridor is 63.5 mm to 72.6 mm, which was based on the cadaver tests carried out in 1970s. After over forty years' development, the vehicle safety has been improved significantly with applications of seat belt and airbag technologies. In the European and China new car assessment program (ENCAP and CNCAP), the higher performance limit for the front impact dummy chest compression is 22mm and the lower performance limit is 50 mm, which is much lower than the dummy chest calibration corridor. In this paper, the dummy rib assembly structure is analyzed and the rib impact FEA simulation was also conducted.
Technical Paper
2014-04-01
Shweta Rawat, Soumya Kanta Das
Abstract With the ever increasing emphasis on vehicle occupant safety, the safety of pedestrians is getting obscured behind the A-pillars that are expanding in order to meet the federal roof crush standards. The serious issue of pillar blind spots poses threats to the pedestrians who easily disappear from driver's field of view. To recognize this blinding danger and design the car around the driver's eye, this paper proposes the implementation of Aluminum Oxynitride marked under name AlON by Surmet Corporation for fabrication of A-pillars that can allow more than 80% visibility through them. AlON is a polycrystalline ceramic with cubic spinel crystal structure and is composed of aluminum, oxygen and nitrogen. With hardness more than 85% than sapphire, its applications range from aerospace to defense purposes which qualify it in terms of strength and thus imply that it can be conveniently used as A-pillars in vehicles. Furthermore, it possesses characteristics of being bonded to metals as well.
Technical Paper
2014-04-01
Jeong Keun Lee, Byung-Jae Ahn, Ye Ri Hong
Abstract In current inflatable curtain airbag development process, the curtain airbag performance is developed sequentially for the airbag coverage, FMVSS 226, FMVSS 214 and NCAP. Because the FMVSS 226 for the ejection mitigation and the NCAP side impact test require the opposite characteristics in terms of the dynamic stiffness of the inflatable curtain airbag, the sequential development process cannot avoid the iteration for dynamic stiffness optimization. Airbag internal pressure characteristics are can be used to evaluate the airbag performance in early stage of the development process, but they cannot predict dynamic energy absorption capability. In order to meet the opposite requirements for both FMVSS 226 and NCAP side impact test, a test and CAE simulation method for the inflatable curtain airbag was developed. The purpose of this study is to standardize the test setup for comparing the energy absorption capability of inflatable curtain airbag and to make criteria for meeting both FMVSS 226 and NCAP early in the program.
Technical Paper
2014-04-01
Yuanyuan Zhang, Shen Wu, Yuliang Shi, Jingang Tu, Jingguo Hu
Abstract The design of front rail is very important to vehicle safety performance. The test and CAE analysis are commonly used methods for design on the component level. Based on experience of impact test designed to simulate the performance of rail in vehicle rigid wall frontal impact, an inclined test is designed to simulate the performance of rail in vehicle offset deformable barrier impact. Two LS-DYNA computer simulation models are established including the effects of plastic strain rate, spot-weld failure, and stamping hardening. The deformation and mechanical properties are studied. The simulation results are correlated to the component tests very well in both cases. The usual impact test and inclined impact test for component rail can represent the main features of the rail performances in the vehicle frontal impact and offset impact respectively. Both of the simulation method and the component test method can support the early stage design for vehicle crash safety.
Technical Paper
2014-04-01
Erdem Uzunsoy, Emmanuel Bolarinwa, Oluremi Olatunbosun, Rui He
Abstract Sloped medians provide a run-off area for errant vehicles so that they can be safely stopped off-road with or without barriers placed in the sloped median. However, in order to optimize the design of sloped medians and the containment barriers, it is essential to accurately model the behavior of vehicles on such sloped terrain surfaces. In this study, models of a vehicle fleet comprising a small sedan and a pickup truck and sloped terrain surface are developed in CarSim™ to simulate errant vehicle behavior on sloped median. Full-scale crash tests were conducted using the vehicle fleet driven across a 9.754 meters wide median with a 6:1 slope at speeds ranging from 30 to 70 km/h. Measured data such as the lateral accelerations of the vehicle as well as chassis rotations (roll and pitch) were synchronized with the vehicle motion obtained from the video data. The measured responses were compared with responses obtained from simulation in CarSim™ to validate the vehicle and slope terrain models.
Technical Paper
2014-04-01
Hang Yin, Weiming Zeng, Guobiao Yang, Songgang Li
Abstract When an object was subjected an impact loading, stress wave was produced in the object. Studying the regularity of stress-wave propagation was significant to the study of objects subjected to impact loading. When stress wave travelled in the object, principal stress on free boundary was useful to theoretical analysis and calculation. In this article, a new kind of dynamic photoelastic apparatus was used. Isochromatic and isoclinic of the object subjected to impact loading could be obtained combining dynamic photoelastic experiment and related test equipment. By analyzing the isoclinic, there would be a conclusion that the angle between the isoclinic and the free boundary was not 0°or 90°. So the values of the two principal stress on the boundary were all not 0. The result obtained from the electrometric method came to the same conclusion. Analysis showed the result of dynamic photoelastic method was compatible with the result of electrometric method. So the method in this article was feasible and accurate.
Technical Paper
2014-04-01
Qiang Yi, Stanley Chien, David Good, Yaobin Chen, Rini Sherony
Abstract According to pedestrian crash data from 2010-2011 the U.S. General Estimates System (GES) and the Fatality Analysis Report System (FARS), more than 39% of pedestrian crash cases occurred at night and poor lighting conditions. The percentage of pedestrian fatalities in night conditions is over 77%. Therefore, evaluating the performance of pedestrian pre-collision systems (PCS) at night is an essential part of the pedestrian PCS performance evaluation. The Transportation Active Safety Institute (TASI) of Indiana University-Purdue University Indianapolis (IUPUI) is conducting research for the establishment of PCS test scenarios and procedures in collaboration with Toyota's Collaborative Safety Research Center. The objective of this paper is to describe the design and implementation of a reconfigurable road lighting system to support the pedestrian PCS performance evaluation for night road lighting conditions. First, the test conditions of the road lighting (light intensity and uniformity) are generated by combining recommendations from road lighting design standards and the average measured lighting levels at various crash locations.
Technical Paper
2014-04-01
Ahmed A. Abdel-Rehim, Ahmed A.A. Attia
Abstract The effect of magnetic field has attracted many researchers to investigate the impact of this type of force on different applications such as combustion and water. Different systems supported by many patents were introduced to the market to treat these applications. In the present study, a series of experiments were conducted to explore the impact of magnetic fuel treatment on engine performance. The magnetic field was produced from two different sources based on permanent and electromagnetic coils. Two engines with different configurations were used. Three fuels were tested, gasoline and diesel as liquid fuels and natural gas as a gaseous fuel. Vast numbers of experiments at different operating conditions were conducted on the two engines. Fuel consumption, output power, and exhaust emissions were analyzed under the exposure of magnetic field. Gasoline was the most affected fuel while other fuels showed less or negligible effect. Magnetic field strength was a key parameter to have any impact on engine performance.
Technical Paper
2014-04-01
Venkat Pisipati, Srikanth Krishnaraj, Edgar Quinto Campos
Abstract Motor vehicle safety standards are getting to be more demanding with time. For automotive interiors, instrument panel (IP) head impact protection is a key requirement of the Federal Motor Vehicle Safety Standard (FMVSS) 201. To ensure compliance of this requirement, head impact tests are conducted at 12 and 15 mph for performance verification. Computer simulation has become more prevalent as the primary development tool due to the significant reduction in time and cost that it offers. LS-DYNA is one of the most commonly used non-linear solvers in the automotive industry, particularly for safety related simulations such as the head impact of automotive interiors. LS-DYNA offers a wide variety of material models, and material type 024 (MAT 024, piecewise linear plasticity) is one of the most popular ones [1]. Although it was initially developed for metals, it is commonly used for polymers as well. LS-DYNA also offers several other material models specifically developed to simulate polymers, such as material types 019, 089, 123, to name a few.
Technical Paper
2014-04-01
Rainer Neumann
Abstract Since 2012, adaptive driving beam (ADB) was homologated first in the ECE world (ECE 123). The idea behind is a camera based lighting system, which enables the driver to achieve at night nearly high beam visibility without glaring oncoming or proceeding vehicles and road users. Once the presence of other vehicles is detected the headlamps change the light pattern and block the light where the oncoming or proceeding vehicles are located. Light sources are typically High Intensity Discharge (HID) bulbs, but today also first LED applications are visible. For SAE, the definition of the parameters and the requested regulation changes to allow such systems are in progress. The paper reports about an extensive study executed in Germany at TU Darmstadt to investigate not only the improvement in visibility for the driver with such systems, but also evaluate the disability and discomfort glare for other road users. The results are demonstrating clearly, that the existing ADB systems do not cause additional glare for the road users and also do not lead to an increased subjective discomfort glare rating.
Technical Paper
2014-04-01
Flaura Winston, Catherine McDonald, Venk Kandadai, Zachary Winston, Thomas Seacrist
Abstract Driving simulators offer a safe alternative to on-road driving for the evaluation of performance. In addition, simulated drives allow for controlled manipulations of traffic situations producing a more consistent and objective assessment experience and outcome measure of crash risk. Yet, few simulator protocols have been validated for their ability to assess driving performance under conditions that result in actual collisions. This paper presents results from a new Simulated Driving Assessment (SDA), a 35- to-40-minute simulated assessment delivered on a Real-Time® simulator. The SDA was developed to represent typical scenarios in which teens crash, based on analyses from the National Motor Vehicle Crash Causation Survey (NMVCCS). A new metric, failure to brake, was calculated for the 7 potential rear-end scenarios included in the SDA and examined according two constructs: experience and skill. The study included an inexperienced group (n=21): 16-17 year olds with 90 days or fewer of provisional licensure, and an experienced group (n=17): 25-50 year olds with at least 5 years of PA licensure, at least 100 miles driven per week and no self-reported collisions in the previous 3 years.
Technical Paper
2014-04-01
Mindy Heading, Douglas Stein, Jeff Dix
Abstract Ejection Mitigation testing is now required by the U.S. government through FMVSS 226 [1]. FMVSS 226 contains the requirement of using a linear guided headform in a horizontal impact test into the inflated curtain, or other ejection mitigation countermeasure that deploys in the event of a rollover. The specification provides dimensions for a featureless headform [2] but there are limited specifications for the headform skin surface condition. In the “Response to Petitions” of the 2011 Final Rule for FMVSS 226 [3], the NHTSA declined the option to include a headform cleaning procedure. This research presents a case study to quantify the effect of changes in the friction between the headform and curtain on the measured excursion. The study presented here shows that a change in friction between the headform and curtain can affect excursion values by up to 135 millimeters (mm).
Technical Paper
2014-04-01
Richard Young
This study reanalyzes the data from a recent experimental report from the University of Utah investigating the effect on driving performance of auditory-vocal secondary tasks (such as cell phone and passenger conversations, speech-to-text, and a complex artificial cognitive task). The current objective is to estimate the relative risk of crashes associated with such auditory-vocal tasks. Contrary to the Utah study's assumption of an increase in crash risk from the attentional effects of cognitive load, a deeper analysis of the Utah data shows that driver self-regulation provides an effective countermeasure that offsets possible increases in crash risk. For example, drivers self-regulated their following distances to compensate for the slight increases in brake response time while performing auditory-vocal tasks. This new finding is supported by naturalistic driving data showing that cell phone conversation does not increase crash risk above that of normal baseline driving. The Utah data are next compared to those from a larger study that included visual-manual as well as auditory-vocal tasks.
Technical Paper
2014-04-01
Madhav Khadilkar
Abstract The purpose of Federal Motor Vehicle Safety Standard 216 is to reduce fatalities and serious injuries when vehicle roof crushes into occupant compartment during rollover crash. Upgraded roof crush resistance standard (571.216a Standard No. 216a) requires vehicle to achieve maximum applied force of 3.0 times unloaded vehicle weight (UVW) on both driver and passenger sides of the roof. (For vehicles with gross vehicle weight rating ≤ 6,000 lb.) This paper provides an overview of current approach for dual side roof strength Finite Element Analysis (FEA) and its limitations. It also proposes a new approach based on powerful features available in virtual tools. In the current approach, passenger side loading follows driver side loading and requires two separate analyses before arriving at final assessment. In the proposed approach only one analysis suffices as driver and passenger side loadings are combined in a single analysis. This is achieved by using sensors to control loadings, resulting in reduced consumption of CPU time (for computer simulation) and disk space utilization without compromising accuracy of current approach.
Technical Paper
2014-04-01
Janet Brelin-Fornari, Sheryl Janca
Abstract The National Highway Traffic Safety Administration (NHTSA) has utilized a two part sled fixture to evaluate a near side test protocol for child restraint systems (CRS). The test was designed to impact the CRS with a fixed door at nearly 20 mph. This paper examines the affects of various fixture parameters on the acceleration and velocity profiles of the two part system during the impact event. It was determined that the kinematic time histories are sensitive to crush energy dissipation (as evaluated with variance in aluminum honeycomb volume) and fixture weight. It was also determined that payload weight, impact speed, and impact plane alignment have a small effect on the acceleration and velocity profiles. Even though the kinematics of the secondary carriage was small with the change in the impact plane alignment, it was determined that the CRS utilized in the standard test would have a 23% reduction in impact energy when compared to the CRS with the impact planes aligned.
Technical Paper
2014-04-01
Sheryl Janca, Kurt Shanks, Janet Brelin-Fornari, Ravi Tangirala, Massoud Tavakoli
Abstract A near-side, rear seat side impact component test, was conducted and validated utilizing a SIDIIs anthropomorphic test device (ATD). The test fixture consisted of the rear seat structure, side door, interior trim, and side airbag curtain module. Test parameters were determined from full scale tests including impact speed, angle of impact, and depth of door intrusion. A comparative assessment was conducted between the full scale test and the deceleration sled test including ATD contact with the vehicle interior, contact duration, sequential timing of ATD contact, and dummy injury measures. Validation was achieved so that the deceleration sled test procedure could be utilized for further evaluations.
Technical Paper
2014-04-01
Jan Vychytil, Jaroslav Manas, Hana Cechova, Stanislav Spirk, Ludek Hyncik, Ludek Kovar
Abstract The paper concerns the development of a new scalable virtual human body model. The model has been developed to assess safety risk during various complex crash scenarios including impacts from different directions. The novel approach described couples the basic multi-body structure with deformable segments, resulting in short calculation time. Each multi-body structure segment carries the particular surface parts that are linked to the segment with non-linear springs representing the behavior of related soft tissues. The response of particular body segments (head, thorax, pelvis, lower extremities) is validated in known impact scenarios and the response of the model is tuned to the experimental corridors obtained from literature. The tuning process involved the adjustment of both model material and numerical parameters in order to get the correct response for all the tests. Several energy level impacts from different directions are usually considered in order to generalize the model; to test its robustness and correct biofidelic performance.
Technical Paper
2014-04-01
Gwansik Park, Taewung Kim, Jeff Crandall, Andy Svendsen, Nathaniel Saunders, Craig Markusic
Abstract The goal of this study was to evaluate the biofidelity of the three computational surrogates (GHBMC model, WorldSID model, and the FTSS ES-2re model) under the side impact rigid wall sled test condition. The responses of the three computational surrogates were compared to those of post mortem human surrogate (PMHS) and objectively evaluated using the correlation and analysis (CORA) rating method. Among the three computational surrogates, the GHBMC model showed the best biofidelity based on the CORA rating score (GHBMC =0.65, WorldSID =0.57, FTSS ES-2re =0.58). In general, the response of the pelvis of all the models showed a good correlation with the PMHS response, while the response of the shoulder and the lower extremity did not. In terms of fracture prediction, the GHBMC model overestimated bone fracture. The results of this study can be effectively utilized in a research that mainly relies on the response of computational surrogates without experimental tests, especially initial development stage of countermeasures for occupant protection from vehicular accidents.
Technical Paper
2014-04-01
Baeyoung Kim, Kangwook Lee, Jeong Keun Lee, June-Young Song
Abstract The role of CAB is protecting the passenger's head during rollover and side crash accidents. However, the performance of HIC and ejection mitigation has trade-off relation, so analytical method to satisfy the HIC and ejection mitigation performance are required. In this study, 3 types of CAB were used for ejection mitigation analysis, drop tower analysis and SINCAP MDB analysis. Impactor which has 18kg mass is impacting the CAB as 20KPH velocity at six impact positions for ejection mitigation analysis. In drop tower analysis, impactor which has 9kg mass is impacting the CAB as 17.7KPH velocity. Acceleration value was derived by drop tower analysis and the tendency of HIC was estimated. Motion data of a vehicle structure was inserted to substructure model and the SID-IIS 5%ile female dummy was used for SINCAP MDB analysis. As a result, HIC and acceleration values were derived by MDB analysis. As a result of ejection mitigation analysis, the impactor was ejected in type 1 of the CAB but the impactor was not ejected in type 2 and type 3.
Technical Paper
2014-04-01
Sebastian Karwaczynski, Mehmet H. Uras
This work is based on a current project funded by the United States Army Small Business Innovation Research (SBIR) Program and is being conducted with the Tank Automotive Research, Development and Engineering Center (TARDEC) Ground Systems Survivability (GSS) Team and Paradigm Research and Engineering. The focus of this project is to develop an advanced and novel sensing and activation strategy for Pyrotechnic Restraint Systems, Air Bags and other systems that may require activation. The overriding technical challenge is to activate these systems to effectively protect the Soldier during blast events in addition to Crash, Rollover and Other Injury Causing events. These activations of Pyrotechnic systems must occur in fractions of milliseconds as compared to typical automotive crashes. By investigating systems outside of typical accelerometer based applications and activations, the potential exists to exploit systems that require little power, are self-contained and provide the required output for the desired result.
Technical Paper
2014-04-01
Ishika Zonina Towfic, Jennifer Johrendt
Abstract The development of a collision severity model can serve as an important tool in understanding the requirements for devising countermeasures to improve occupant safety and traffic safety. Collision type, weather conditions, and driver intoxication are some of the factors that may influence motor vehicle collisions. The objective of this study is to use artificial neural networks (ANNs) to identify the major determinants or contributors to fatal collisions based on various driver, vehicle, and environment characteristics obtained from collision data from Transport Canada. The developed model will have the capability to predict similar collision outcomes based on the variables analyzed in this study. A multilayer perceptron (MLP) neural network model with feed-forward back-propagation architecture is used to develop a generalized model for predicting collision severity. The model output, collision severity, is divided into three categories - fatal, injury, and property damage only.
Technical Paper
2014-04-01
John Patalak, Thomas Gideon, Don Krueger
First required in 1970 in NASCAR® (National Association for Stock Car Auto Racing, Inc) the driver's window safety net or driver's window net has continually evolved and improved. The driver's window net has played an important role in protecting race car drivers from injury. Driver's window nets were originally used to help keep the driver's upper torso, head and arms inside the interior of the race vehicle during crashes. As restraint systems were improved, the role of the driver's window net in stock car racing has transitioned to keeping flailing hands inside the interior of the car while also serving as a shield to protect the driver from intruding debris. This paper describes three separate window net and window net mounting tests and the use of these tests to design an improved window net mounting system. Also shown are test results of previously used window net mounting systems and the improved NASCAR system which has been incorporated into the 2013 NASCAR Sprint Cup, Nationwide Series, and Camping World Truck Series vehicles.
Technical Paper
2014-04-01
Bradley Orme, Robert V. Walsh, Scott Westoby
Abstract Changes in the automotive supply chain over the past several years were brought about by global economic pressures, and forced some materials into tight supply as the industry started its recovery. One such material is polyamide 6,6 fiber (PA 6,6) used for airbags, which was in tight supply in 2008-09. This, with the availability of new low temperature inflators caused some airbag module manufacturers to revisit the use of polyester (PET), which had been used sporadically and in small quantities since the 1970s, although the overwhelming majority of airbags used PA 6,6. Over the last several years PET has been adopted for use in a small number of airbag programs to reduce supply concerns, but this use has come with performance tradeoffs of higher weight, lower tear and seam properties, and other changes. Still, the lower polymer cost of PET has driven a wider evaluation. Polyamide 6,6 and polyester are not equivalent fibers, and differences in thermal capacity, toughness, modulus, and other properties result in different fabric performance.
Technical Paper
2014-04-01
Vesna Savic, Matthew Pawlicki, Paul Krajewski, Mark Voss, Louis Hector, Keith Snavely
Abstract Global regulations intended to enhance pedestrian protection in a vehicle collision, thereby reducing the severity of pedestrian injuries, are presenting significant challenges to vehicle designers. Vehicle hoods, for example, must absorb a significant amount of energy over a small area while precluding impact with a hard engine compartment component. In this paper, a simple passive approach for pedestrian protection is introduced in which thin metal alloy sheets are bent to follow a C-shaped cross-sectional profile thereby giving them energy absorbing capacity during impact when affixed to the underside of a hood. Materials considered were aluminum (6111-T4, 5182-O) and magnesium (AZ31-O, AZ61-O, ZEK100) alloys. To evaluate the material effect on the head injury criterion (HIC) score without a hood, each C-channel absorber was crushed in a drop tower test using a small dart. Two high speed cameras captured dart image data before and during impact from which HIC scores were computed with stereo digital image correlation (DIC).
Technical Paper
2014-04-01
Hiroyuki Asanuma, Yukou Takahashi, Miwako Ikeda, Toshiyuki Yanaoka
Abstract Japanese accident statistics show that despite the decreasing trend of the overall traffic fatalities, more than 1,000 pedestrians are still killed annually in Japan. One way to develop further understanding of real-world pedestrian accidents is to reconstruct a variety of accident scenarios dynamically using computational models. Some of the past studies done by the authors' group have used a simplified vehicle model to investigate pedestrian lower limb injuries. However, loadings to the upper body also need to be reproduced to predict damage to the full body of a pedestrian. As a step toward this goal, this study aimed to develop a simplified vehicle model capable of reproducing pedestrian full-body kinematics and pelvis and lower limb injury measures. The simplified vehicle model was comprised of four parts: windshield, hood, bumper and lower part of the bumper. Several different models were developed using different combinations of geometric and stiffness representation. A unique model called a multi-layer model developed in this study represented each of the hood and the windshield with a stack of the panel representing the entire area of these components, while applying localized stiffness characteristics and contact definition with a particular pedestrian body region that contacts with the layer represented by the stiffness characteristics.
Technical Paper
2014-04-01
Bingbing Nie, Qing Zhou, Yong Xia, Jisi Tang
Vehicle hood styling has significant influence on headform kinematics in assessment tests of pedestrian impact protection performance. Pedestrian headform kinematics on vehicle front-end models with different hood styling characteristics is analyzed based on finite element modeling. More elevated feature lines near hood boundary and the following continuous hood surface towards fender will result in a different headform motion. It can lead to larger deformation space, more rotation and earlier rebound of the headform impactor, which will benefit the head impact protection performance. In addition, hood geometry characteristics such as hood angle and curvature have effects on structural stiffness. Therefore, inclusion of considerations on pedestrian head protection into the vehicle hood styling design stage may lead to a more effective and efficient engineering design process on headform impact analysis.
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