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Viewing 181 to 210 of 15806
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.
Technical Paper
2014-04-01
Tushar Baviskar, Jagadish Mahadevaiah, Vijay Shankar Iyer, Mark Neal
Abstract EEVC WG17 Upper Leg impactors have been used to assess the risk of pedestrian upper leg injuries with respect to regulatory and consumer metric rating requirements. The paper compares the femur injury responses between the finite element models of the EEVC WG17 Upper Leg impactor, the FlexPLI and the 50th percentile male GM/UVa pedestrian model on two sample vehicle architectures, for a sedan and a sports utility vehicle. The study shows that the peak femur load and maximum bending moment response are higher in the EEVC WG17 Upper Leg impactor than the FlexPLI and the human body model. Variation studies are carried out to study the influence of impact location on the vehicle, impactor knee height, additional upper body mass and human body model size on the femur injury responses. The FlexPLI femur responses correlate better with those of the human body model and indicate that the impactor has the potential to be an effective surrogate leg form of a pedestrian with appropriate refinement.
Technical Paper
2014-04-01
Yukou Takahashi, Miwako Ikeda
Abstract The validity of evaluating FlexPLI peak injury measures has been shown by the correlation of the peak measures between a human FE model and a FlexPLI FE model. However, comparisons of tibia bending moment time histories (BMTHs) between these models show that the FlexPLI model exhibits a higher degree of oscillatory behavior than the human model. The goal of this study was to identify potential improvements to the FlexPLI such that the legform provides more biofidelic tibia BMTHs at the normal standing height. Impact simulations using a human FE model and a FlexPLI FE model were conducted against simplified vehicle models to compare tibia BMTHs. The same series of impact simulations were conducted using the FlexPLI models that incorporated potential measures to identify measures effective for further enhancement of the biofidelity. An additional analysis was also conducted to investigate the key factor for minimizing the oscillation of the tibia BMTH. The results of this study showed that the change of the mass distribution between the bony and flesh parts, along with the addition of the mass compensating for the upper body, provide more biofidelic FlexPLI tibia BMTHs, when used at the normal standing height.
Technical Paper
2014-04-01
Kambiz Jahani, Sajjad Beigmoradi
Abstract Adequate visibility through the automobile windscreen is a critical aspect of driving, most often at very low temperatures when ice tends to be formed on the windscreen. The geometry of the existing defroster system needs to be improved in the vehicles, with the main aim of substantial increase in air mass flow reaching the windscreen through defroster nozzles and appropriate velocity distribution over the windscreen, while respecting all packaging constraints. The reason of this study is to investigate the windscreen deicing behavior of a vehicle by means of Computational Fluid Dynamics (CFD) with the main concern of improving deicing process by design an appropriate defroster. Two different defrosters with completely different geometry are considered for this purpose. A detailed full interior model of an existing vehicle is created via CAE tools. A transient simulation is performed and results are extracted to show how a proper design of the defroster will lead to considerable improve in deicing process.
Technical Paper
2014-04-01
Sanjeev Kumar, Rahul Bettakote, Pinak Deb
Abstract Offset crash compliance of a compact car is severe due to the compact layout and stringent fuel economy, weight and cost targets. Scope of the current work is to improve the structural crash performance of a compact car through CAE, in order to meet the offset frontal crash requirements as per ECE R94 Regulation. The project has been classified in three main phases. First phase includes the evaluation of baseline vehicle in CAE. In order to ensure the accuracy of CAE prediction, a methodology for predicting Spotweld rupture was implemented. Using this methodology, it is possible to find out the location and time of spotweld rupture as well as propagation of spotweld rupture in CAE. CAE results of spotweld rupture prediction showed good agreement with the physical test. In second phase, design iterations were carried out in order to meet the performance targets of structural deformation. At critical locations of spotweld rupture, spotwelds were reinforced by addition of arc welds tugs and bolts.
Technical Paper
2014-04-01
Bryan Styles, Jeffrey Santrock, Curtis Vincent, Michael Leffert, Narasimha Putcha
An evaluation methodology has been developed for assessing the suitability of R-1234yf in vehicles. This relates primarily to evaluating the flammability of R-1234yf in the engine compartment during a frontal collision. This paper will discuss the process followed in the methodology, the technical rationale for this process, and the results of the analysis. The specific types of analysis included in the methodology are: exhaust-system thermal characterization, computer simulated crash tests, actual crash tests, teardown and examination of crashed parts, and releases of refrigerant onto hot exhaust manifolds. Each type of analysis was logically ordered and combined to produce a comprehensive evaluation methodology. This methodology has been applied and demonstrates that R-1234yf is difficult to ignite when factors that occur in frontal crashes are simultaneously considered. Factors considered in this analysis include: crush and deformation of the vehicle structure, airflow in the engine compartment, exhaust system temperatures during different driving scenarios, and coolant release due to damage of the engine coolant system.
Technical Paper
2014-04-01
Sanjeev Kumar, Deepak Katyal, Amit Singh
Abstract Recent advancement in numerical solutions and advanced computational power has given a new dimension to the design and development of new products. The current paper focuses on the details of work done in order to improve the vehicle performance in Offset deformable Barrier (ODB) crash as per ECER-94. A Hybrid approach involving the Structural Crash CAE as well as Multi-body Simulation in MADYMO has been adopted. In first phase of the development, CAE results of Structural deformation as well as Occupant injury of the baseline model were correlated with physical test data. The second phase includes the improvement in intrusion and crash energy absorption by structural countermeasures in the vehicle body. In third phase parametric study has been carried out via Madymo simulation in order to decide on the factors which can be controlled in order to mitigate the Occupant injury. Recommendations of Madymo simulation have been confirmed by conducting Physical sled tests. Finally a cost and weight effective countermeasure package which involves the modification in Body structure and Restraint system has been developed in order to comply with the ECE R-94 offset crash regulation.
Technical Paper
2014-04-01
Alan R. Wedgewood, Patrick Granowicz, Zhenyu Zhang
Abstract Materials used in automotive components play a key role in providing crash safety to passengers and pedestrians. DuPont's lightweight hybrid material technology, which combines injection molded fiber reinforced plastics with drape molded woven composite materials, provides safety engineers with stiff energy absorbing alternatives. In an effort to validate the hybrid material's crash performance while avoiding expensive crash testing, numerical tools and methodologies are applied in evaluation of a hybrid composite test beam. Multi-scale material models capturing nonlinear strain-rate dependency, anisotropic characteristics, and failure criteria, are calibrated on a fiber reinforced plastic and a woven fabric. The fiber orientation and warp/weft angles were extracted from injection and drape molding simulation. The material laws and orientation information are coupled in a single finite element analysis to predict the performance of the hybrid composite beam under a dynamic three point bending load.
Technical Paper
2014-04-01
David LeBlanc, Mark Gilbert, Stephen Stachowski, Rini Sherony
Pre-collision systems (PCS) use forward-looking sensors to detect the location and motion of vehicles ahead and provide a sequence of actions to help the driver either avoid striking the rear-end of another vehicle or mitigate the severity of the crash. The actions include driver alerts, amplification of driver braking as distance decreases (dynamic brake support, DBS), and automatic braking if the driver has not acted or has not acted sufficiently (crash imminent braking, CIB). Recent efforts by various organizations have sought to define PCS objective test procedures and test equipment in support of consumer information programs and potential certification. This paper presents results and insights from conducting DBS and CIB tests on two production vehicles sold in the US. Eleven scenarios are used to assess the systems' performance. The two systems' performance shows that commercial systems can be quite different. Also demonstrated is the experience with test equipment, including a towable target that has been designed for resiliency and radar signature, a braking robot, and bumper guard.
Technical Paper
2014-04-01
Chi-Chun Yao, Jin-Yan Hsu, Yu-Sheng Liao, Ming Hung Li
Abstract Vehicle Rollover Prevention/Warning Systems have recently been an important topic in Advanced Driver Assistance Systems (ADAS) of automotive electronics field. This paper will propose a rollover-prevention system implementation with vehicle dynamic model, video-detection technique and rollover index to help the driver avoid accidents as driving into a curve. Due to the reason that vehicle rollover motion analysis needs complicated computation and accurate parameters of vehicle stability in real time, in the first stage a vehicle dynamic model based on Extended Kalman Filter (EKF) algorithm is built, which can estimate vehicle roll/yaw motion in the curve by vehicle sensors. And then the image-based technique will be employed in detecting the front road curvature, and combined in the system to predict vehicle steering status. The final stage is to apply the vehicle rollover index with estimated vehicle motion to predict the dangerous level to drivers for warning. In the system validation, a Digital Signal Processor (DSP) with Microcontroller Unit (MCU) hardware structure is equipped and implemented in our vehicle experimental platform.
Technical Paper
2014-04-01
Cheng-Lung Lee, Hongyi Zhang, Hong Nguyen, Yu-Ting Wu, Christopher Smalley, Utayba Mohammad, Mark J. Paulik
Abstract A novel multi-modal scene segmentation algorithm for obstacle identification and masking is presented in this work. A co-registered data set is generated from monocular camera and light detection and ranging (LIDAR) sensors. This calibrated data enables 3D scene information to be mapped to time-synchronized 2D camera images, where discontinuities in the ranging data indicate the increased likelihood of obstacle edges. Applications include Advanced Driver Assistance Systems (ADAS) which address lane-departure, pedestrian protection and collision avoidance and require both high-quality image segmentation and computational efficiency. Simulated and experimental results that demonstrate system performance are presented.
Technical Paper
2014-04-01
Louis Tijerina, James Sayer
Abstract The objectives of this study were a) to determine how expert judges categorized valid Integrated Vehicle-Based Safety Systems (IVBSS) Forward Collision Warning (FCW) events from review of naturalistic driving data; and b) to determine how consistent these categorizations were across the judges working in pairs. FCW event data were gathered from 108 drivers who drove instrumented vehicles for 6 weeks each. The data included video of the driver and road scene ahead, beside, and behind the vehicle; audio of the FCW alert onset; and engineering data such as speed and braking applications. Six automotive safety experts examined 197 ‘valid’ (i.e., conditions met design intent) FCW events and categorized each according to a taxonomy of primary contributing factors. Results indicated that of these valid FCW events, between 55% and 73% could be considered ‘nuisance alerts’ by the driver. These were the FCW alerts presented in benign conditions (e.g., lead-vehicle turning) or as a result of deliberate driver action (aggressive driving).
Technical Paper
2014-04-01
Edgar Yoshio Morales Teraoka, Shin Tanaka, Tsutomu Mochida
Abstract We develop a simulation tool which reproduces lane departure crashes for the purpose of estimating potential benefits of Lane Departure Warning (LDW) systems in the American traffic environment. Tools that allow a fast evaluation of active safety systems are useful to make better systems, more effective in the real world; however accuracy of the results is always an issue. Our proposed approach is based on developing a simulation tool that reproduces lane departure crashes, then adding the effect of the LDW to compare the cases with and without the safety system, and finally comparing the results of different settings of the safety system. Here, the accurate reproduction of the relevant crashes determines the reliability of the results. In this paper, we present the reproduction of the lane departure crashes occurred in American roads in one year, by using data distributions obtained from retrospective crash databases. We analyze data from NASS/GES1 and NASS/CDS2 to obtain the characteristics of lane departure accidents in the USA.
Technical Paper
2014-04-01
Gauri Ranadive, Anindya Deb, Bisheshwar Haorongbam
Abstract Load cells and accelerometers are commonly used sensors for capturing impact responses. The basic objective of the present study is to assess the accuracy of responses recorded by the said transducers when these are mounted on a moving impactor. In the present work, evaluation of the responses obtained from a drop-weight impact testing set-up for an axially loaded specimen has been carried out with the aid of an equivalent lumped parameter model (LPM) of the set-up. In this idealization, a test component such as a steel double hat section subjected to axial impact load is represented with a nonlinear spring. Both the load cell and the accelerometer are represented with linear springs, while the impactor comprising a hammer and a main body with the load cell in between are modelled as rigid masses. An experimentally obtained force-displacement response is assumed to be a true behavior of a specimen. By specifying an impact velocity to the impactor as an initial condition and using an implicit time integration technique, it is shown that the model accurately reproduces the input load-displacement behavior of the nonlinear spring corresponding to the tested component.
Technical Paper
2014-04-01
Prasad Rao Yerraguntla, Shashi Kulkarni, Deepak Asthana
Abstract Automotive Audio Signaling system is very vital and is controlled by local regulatory requirements. In India, usage of horn is very frequent due to highly congested traffic conditions, and is in the order of 10 to 12 times per kilometer. This results in the deterioration of the “contact”, which enables the functioning of the device. Hence the device requires premature replacement or frequent tuning, which are time consuming and results an increase in warranty costs and cost of service as well. Thus, to overcome this problem a unique and novel approach is proposed in this paper which enhances the life of the automobile horn, by implementing an additional pair of Contacts on circuit breakers, providing a parallel path for the power supply. This effort ensures that the life of the horn is increased by 5 times than the existing design. In addition, this approach completely eliminates the problems of premature failure or frequent tuning, yet without any change in the physical dimensions of the device, thus ensuring that no additional engineering efforts are required for its implementation.
Technical Paper
2014-04-01
Greg A. Sullenberger
Abstract A well-established methodology has often been used to calculate a speed-at-impact from the overall distance that a pedestrian is thrown as a result of a vehicle-pedestrian impact. (Searle, SAE #831622 and SAE #930659). The formulae were derived for use on typical road surfaces, such as asphalt, concrete, and grass. Significant testing has been done to validate the formulae on these normal surfaces. The current research was completed to assess if the same formulae are also applicable to lower-friction surfaces, e.g. snow, ice. Test dummies were impacted by automobiles or launched from a ramp in order to simulate the airborne trajectory of a vehicle-pedestrian collision. Speeds were measured with a radar unit and/or the analysis of high speed video. The overall distance traveled by the dummy from impact/launch to final rest was measured. A calculated friction value for the overall throw distance was based upon the known speed and distance and a known or approximated angle of takeoff.
Technical Paper
2014-04-01
Raed E. El-jawahri, Tony R. Laituri, Agnes S. Kim, Stephen W. Rouhana, Para V. Weerappuli
In the present study, transfer equations relating the responses of post-mortem human subjects (PMHS) to the mid-sized male Hybrid III test dummy (HIII50) under matched, or nearly-identical, loading conditions were developed via math modeling. Specifically, validated finite element (FE) models of the Ford Human Body Model (FHBM) and the HIII50 were used to generate sets of matched cases (i.e., 256 frontal impact cases involving different impact speeds, severities, and PMHS age). Regression analyses were subsequently performed on the resulting age-dependent FHBM- and HIII50-based responses. This approach was conducted for five different body regions: head, neck, chest, femur, and tibia. All of the resulting regression equations, correlation coefficients, and response ratios (PHMS relative to HIII50) were consistent with the limited available test-based results.
Technical Paper
2014-04-01
Toshiyuki Yanaoka, Yasuhiro Dokko
Abstract The high frequency of fatal head injuries of elderly people in traffic accidents is one of the important issues in Japan. One of the causes may be vulnerability of the aged brain. While a human head/brain FE model is a useful tool to investigate head injury mechanism, there has not been a research result using a model considering the structural and qualitative changes of the brain by aging. The objective of this study was to clarify the generational difference of intracranial responses related to traumatic brain injuries (TBI) under impact loading. In this study, the human head/brain FE models in their twenties (20s) and seventies (70s) were used. They were developed by reflecting the age-specific characteristics, such as shape/size and stiffness of brain matter and blood vessels, to the baseline model developed by Global Human Body Models Consortium (GHBMC) LLC. The generational difference of intracranial responses related to TBI, such as cumulative strain damage measure (CSDM), dilatational damage measure (DDM) and elongation of bridging vein (BV), were studied using the models.
Technical Paper
2014-04-01
William R. Bussone, Michael Prange
Abstract Few studies have investigated pediatric head injury mechanics with subjects below the age of 8 years. This paper presents non-injurious head accelerations during various activities for young children (2 to 7 years old). Eight males and five females aged 2-7 years old were equipped with a head sensor package and head kinematics were measured while performing a series of playground-type activities. The maximum peak resultant accelerations were 29.5 G and 2745 rad/s2. The range of peak accelerations was 2.7 G to 29.5 G. The range of peak angular velocities was 4.2 rad/s to 22.4 rad/s. The range of peak angular accelerations was 174 rad/s2 to 2745 rad/s2. Mean peak resultant values across all participants and activities were 13.8 G (range 2.4 G to 13.8 G), 12.8 rad/s (range 4.0 rad/s to 12.8 rad/s), and 1375 rad/s2 (range 105 rad/s2 to 1375 rad/s2) for linear acceleration, angular velocity, and angular acceleration, respectively. The peak accelerations measured in this study were similar to older children performing similar tasks.
Technical Paper
2014-04-01
Ellen L. Lee, Patrick J. Lee, Wilson C. Hayes
Abstract Non-neutral posture prior to impact is one of many factors thought to influence the onset and severity of whiplash associated disorders following low speed, rear impact collisions. The Graphical Articulated Total Body Model (GATB) is one simulation tool that has been used to investigate injury risk in rear impact collisions, though the model has not previously been validated for occupants in non-neutral postures. The main purpose of this study was to evaluate the performance of the GATB model during low speed rear impacts in out-of-position postures, by comparing simulations to previously published volunteer head accelerations. Twelve simulations (four occupants in each of three postures) were performed. Results demonstrated good agreement between the GATB simulations and the volunteer kinematics, with a mean error for peak head acceleration of 3.4 ± 13%. In addition, influence of out-of-position postures on the risk of whiplash injury for different sized occupants was investigated using the Neck Injury Criterion (NIC).
Technical Paper
2014-04-01
Chinmoy Pal, Tomosaburo Okabe, Kulothungan Vimalathithan, Muthukumar Muthanandam, Jeyabharath Manoharan, Satheesh Narayanan
Abstract A comprehensive analysis was performed to evaluate the effect of BMI on different body region injuries for side impact. The accident data for this study was taken from the National Automotive Sampling System-Crashworthiness Data System (NASS-CDS). It was found that the mean BMI values for driver and front passengers increases over the years in the US. To study the effect of BMI, the range was divided into three groups: Thin (BMI<21), Normal (BMI 24-27) and Obese (BMI>30). Other important variables considered for this study were model year (MY1995-99 for old vehicles & MY2000-08 for newer vehicles), impact location (side-front F, side-center P & side-distributed Y) and direction of force (8-10 o'clock for nearside & 2-4 o'clock for far-side). Accident cases involving older occupants above 60 years was omitted in order to minimize the bone strength depreciation effect. Results of the present study indicated that the Model Year has influence on lower extremity injuries. Occurrence of pelvis injury was found to be influenced by BMI and was validated with logistic regression analysis.
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