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Viewing 1 to 30 of 2181
2011-04-12
Technical Paper
2011-01-0274
David C. Viano
Purpose: This study presents cases of fracture-dislocation of the thoracic spine in extension during severe rear impacts. The mechanism of injury was investigated. Methods: Four crashes were investigated where a lap-shoulder-belted, front-seat occupant experienced fracture-dislocation of the thoracic spine and paraplegia in a severe rear impact. Police, investigator and medical records were reviewed, the vehicle was inspected and the seat detrimmed. Vehicle dynamics, occupant kinematics and injury mechanisms were determined in this case study. Results: Each case involved a lap-shoulder-belted occupant in a high retention seat with ≻1,700 Nm moment or ≻5.5 kN strength for rearward loading. The crashes were offset rear impacts with 40-56 km/h delta V involving under-ride or override by the impacting vehicle and yaw of the struck vehicle. In each case, the occupant's pelvis was restrained on the seat by the open perimeter frame of the seatback and lap belt.
2010-04-12
Journal Article
2010-01-0516
Michelle F. Heller, William N. Newberry, Janine E. Smedley, Senthil K. Eswaran, Jeffrey J. Croteau, Michael R. Carhart
Rollover events involving multiple revolutions are dynamic, high-energy, chaotic events that may result in occupant injury. As such, there is ongoing discussion regarding methods that may reduce injury potential during rollovers. It has been suggested that increasing a vehicle's roof strength will mitigate injury potential. However, numerous experimental studies and published field accident data analyses have failed to show a causal relationship between roof deformation and occupant injury. The current study examines occupant kinematics and injury mechanisms during dolly rollover testing of a vehicle with a high roof strength-to-weight ratio (SWR = 4.8). String potentiometers and high-speed video cameras were used to capture and quantify the dynamic roof motion throughout the rollover. Instrumented Anthropomorphic Test Devices (ATDs) in the front occupant positions allowed for the assessment of occupant kinematics, loading, and injury mechanics during the rollover event.
2011-04-12
Technical Paper
2011-01-0014
Yuji Fujiyama, Daisuke Sonoyama, Kazuhiro Obayashi, Qiang Yu PhD
Evaluations of dummy injury readings obtained in regulatory crash tests and new car assessment program tests provide indices for the development of crash safety performance in the process of developing new vehicles. Based on these indices, vehicle body structures and occupant restraint systems are designed to meet the required occupant injury criteria. There are many types of regulatory tests and new car assessment program tests that are conducted to evaluate vehicle safety performance in side impacts. Factoring all of the multiple test configurations into the development of new vehicles requires advanced design capabilities based on a good understanding of the mechanisms producing dummy injury readings. In recent years, advances in computer-aided engineering (CAE) tools and computer processing power have made it possible to run simulations of occupant restraint systems such as side airbags and seatbelts.
2013-04-08
Technical Paper
2013-01-0805
John J. Christopher, Mark R. Sochor, Joseph Pellettiere, Robert Scott Salzar
Monitoring head accelerations as an indicator of possible brain injury may lead to faster identification of injury and treatments. This study investigates the skull-coupling of a tri-axial accelerometer mounted to a back molar and compares it with a tri-axial accelerometer inserted in the boney ear canal. These tri-axial accelerometers were mounted to three post mortem human surrogate (PMHS) skulls, and compared with a rigid, skull-mounted laboratory sensor reference cube. Each specimen was subjected to both a high-g loading from a vertical drop tower and a low frequency cyclic loading from a shaker device. The specimens were subjected to an approximate 150g input acceleration on the drop tower, and up to 10g at a frequency of 9Hz on the shaker device. Each specimen was tested on all three of the anatomical axes on both the drop tower and the cyclic shaker.
2013-04-08
Technical Paper
2013-01-1246
Bhavesh Prabhulal Gangani, Anil Vidye
Improvised Explosive Devices (IEDs) and Anti-Tank (AT) mines are a significant threat for military vehicles and their occupants. These explosive devices are designed for the destruction and damage of armored and other vehicles, by using them in battle fields on routes of army vehicles. The blast event results in effects like shockwave, fragments, fire, gases, blast overpressure as well as the vertical impulse load. A blast event affects occupants inside the vehicle in the form of various types of injuries (lower leg, spinal, chest, head etc) and trauma. The Lower leg is the foremost injured body region in a blast event. The term lower leg is used to designate the tibia, fibula and the foot/ankle complex in this paper. Detonations occurring under a vehicle produce high velocity floorboard flutter/deformation and transmit axial loads to lower leg and create injuries.
2013-04-08
Technical Paper
2013-01-1242
Yasuhiro Dokko, Toshiyuki Yanaoka, Kazuki Ohashi
Corresponding to the increasing need for the protection of elderly people from traffic accidents, the authors have been developing age-specific human FE models capable of predicting body kinematics and skeletal injuries for younger adult (35y.o.) and the elderly (75y.o.). The models have been developed and validated part by part referring to the literature and then integrated into whole bodies. Validation had been conducted in order of single bones, components and whole body. Whole body kinematics in frontal impact had been validated against the PMHS frontal belt restrained sled tests series, resulting in good biofidelity scores. In this study, the models were validated for lateral impact. The models were validated against several impact tests of body regions from ISO-TR9790 and against recently published full scale lateral sled tests for whole body kinematics. In most cases, the results showed good biofidelity of the models.
2013-11-11
Technical Paper
2013-22-0005
Vishal Gupta, King H. Yang
Most studies of pedestrian injuries focus on reducing traumatic injuries due to the primary impact between the vehicle and the pedestrian. However, based on the Pedestrian Crash Data Study (PCDS), some researchers concluded that one of the leading causes of head injury for pedestrian crashes can be attributed to the secondary impact, defined as the impact of the pedestrian with the ground after the primary impact of the pedestrian with the vehicle. The purpose of this study is to understand if different vehicle front-end profiles can affect the risk of pedestrian secondary head impact with the ground and thus help in reducing the risk of head injury during secondary head impact with ground. Pedestrian responses were studied using several front-end profiles based off a mid-size vehicle and a SUV that have been validated previously along with several MADYMO pedestrian models.
2013-11-11
Technical Paper
2013-22-0003
David Poulard, François Bermond, Karine Bruyère
Thoracic injuries are a major cause of mortality in frontal collisions, especially for elderly female and obese people. Car occupant individual characteristics like age, gender and Body Mass Index (BMI) are known to influence human vulnerability tolerance in crashes. The objective of the this study was to perform in vivo test experiments to quantify the influence of subject characteristics in terms of age, gender and anthropometry and on thorax mechanical response variability under belt loading. Thirty-nine relaxed volunteers of different anthropometries, genders and age were submitted to non-injurious sled tests (4 g, 8 km/h) with a sled buck representing the environment of a front passenger restrained by a 3-point belt. A resulting shoulder belt force FRes was computed using the external and internal shoulder belt loads and considering shoulder belt geometry.
2013-11-11
Technical Paper
2013-22-0009
Sijia Zhang, Kristen J. Nicholson, Jenell R. Smith, Taylor M. Gilliland, Peter P. Syré, Beth A. Winkelstein
Both traumatic and slow-onset disc herniation can directly compress and/or chemically irritate cervical nerve roots, and both types of root injury elicit pain in animal models of radiculopathy. This study investigated the relative contributions of mechanical compression and chemical irritation of the nerve root to spinal regulation of neuronal activity using several outcomes. Modifications of two proteins known to regulate neurotransmission in the spinal cord, the neuropeptide calcitonin gene-related peptide (CGRP) and glutamate transporter 1 (GLT-1), were assessed in a rat model after painful cervical nerve root injuries using a mechanical compression, chemical irritation or their combination of injury. Only injuries with compression induced sustained behavioral hypersensitivity (p≤0.05) for two weeks and significant decreases (p<0.037) in CGRP and GLT-1 immunoreactivity to nearly half that of sham levels in the superficial dorsal horn.
2013-11-11
Technical Paper
2013-22-0010
Erik G. Takhounts, Matthew J. Craig, Kevin Moorhouse, Joe McFadden, Vikas Hasija
Rotational motion of the head as a mechanism for brain injury was proposed back in the 1940s. Since then a multitude of research studies by various institutions were conducted to confirm/reject this hypothesis. Most of the studies were conducted on animals and concluded that rotational kinematics experienced by the animal's head may cause axonal deformations large enough to induce their functional deficit. Other studies utilized physical and mathematical models of human and animal heads to derive brain injury criteria based on deformation/pressure histories computed from their models.
2013-11-11
Technical Paper
2013-22-0007
Becky Mueller, Charles Farmer, Jessica Jermakian, David Zuby
Pedestrian protection evaluations have been developed to encourage vehicle front-end designs that mitigate the consequences of vehicle-to-pedestrian crashes. The European New Car Assessment Program (Euro NCAP) evaluates pedestrian head protection with impacts against vehicle hood, windshield, and A-pillars. The Global Technical Regulation No. 9 (GTR 9), being evaluated for U.S. regulation, limits head protection evaluations to impacts against vehicle hoods. The objective of this study was to compare results from pedestrian head impact testing to the real-world rates of fatal and incapacitating injuries in U.S. pedestrian crashes. Data from police reported pedestrian crashes in 14 states were used to calculate real-world fatal and incapacitating injury rates for seven 2002-07 small cars. Rates were 2.17-4.04 per 100 pedestrians struck for fatal injuries and 10.45-15.35 for incapacitating injuries.
2013-11-11
Technical Paper
2013-22-0008
Yasuhiro Matsui, Shoko Oikawa, Kenichi Ando
The first purpose of this study is to clarify the relation between the car impact velocity and pedestrian injury severity or mortality risk. We investigated the frequency of serious injuries and fatalities of pedestrians using vehicle-pedestrian accident data from the database of the Institute for Traffic Accident Research and Data Analysis (ITARDA) in Japan. The vehicle types considered are sedans, minivans, and box vans (ordinary automobiles) and light passenger cars and light cargo vans (light automobiles). The results revealed that a 10-km/h reduction in impact velocity could mitigate severe pedestrian injuries in cases involving impact velocities of 40 km/h or more for the five vehicle types analyzed. Specifically, if the impact velocity was 30 km/h or less, the frequency of serious injuries was less than 27% and the frequency of fatalities was less than 5% for the five vehicle types.
2013-11-11
Technical Paper
2013-22-0011
Chantal S. Parenteau, Peter Ehrlich, Linda Ma, Grace L. Su, Sven Holcombe, Stewart C. Wang
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.
2013-11-11
Technical Paper
2013-22-0012
Yuan-Chiao Lu, Andrew R. Kemper, Scott Gayzik, Costin D. Untaroiu, Philippe Beillas
The liver is one of the most frequently injured abdominal organs during motor vehicle crashes. Realistic numerical assessments of liver injury risk for the entire occupant population require incorporating inter-subject variations into numerical models. The main objective of this study was to quantify the shape variations of human liver in a seated posture and the statistical distributions of its material properties. Statistical shape analysis was applied to construct shape models of the livers of 15 adult human subjects, recorded in a typical seated (occupant) posture. The principal component analysis was then utilized to obtain the modes of variation, the mean model, and 95% statistical boundary shape models. In addition, a total of 52 tensile tests were performed on the parenchyma of three fresh human livers at four loading rates (0.01, 0.1, 1, and 10 s−1) to characterize the rate-dependent and failure properties of the human liver.
2013-04-08
Technical Paper
2013-01-0456
Binhui Jiang, Haojie Mao, Libo Cao, King H. Yang
Previously, a 10-year-old (YO) pediatric thorax finite element model (FEM) was developed and verified against child chest stiffness data measured from clinical cardiopulmonary resuscitation (CPR). However, the CPR experiments were performed at relatively low speeds, with a maximum loading rate of 250 mm/s. Studies showed that the biomechanical responses of human thorax exhibited rate sensitive characteristics. As such, the studies of dynamic responses of the pediatric thorax FEM are needed. Experimental pediatric cadaver data in frontal pendulum impacts and diagonal belt dynamic loading tests were used for dynamic validation. Thoracic force-deflection curves between test and simulation were compared. Strains predicted by the FEM and the injuries observed in the cadaver tests were also compared for injury assessment and analysis. This study helped to further improve the 10 YO pediatric thorax FEM.
2013-04-08
Journal Article
2013-01-0466
Yibing Shi, Guy Nusholtz
Regression models are used to understand the relative fatality risk for drivers in front-front and front-left crashes. The field accident data used for the regressions were extracted by NHTSA from the FARS database for model years 2000-2007 vehicles in calendar years 2002-2008. Multiple logistic regressions are structured and carried out to model a log-linear relationship between risk ratio and the independent vehicle and driver parameters. For front-front crashes, the regression identifies mass ratio, belt use, and driver age as statistically significant parameters (p-values less than 1%) associated with the risk ratio. The vehicle type and presence of the ESC are found to be related with less statistical significance (p-values between 1% and 5%). For front-left crashes the driver risk ratio is also found to have a log-log linear relationship with vehicle mass ratio.
2004-03-08
Technical Paper
2004-01-0188
Christoph Knotz, Bernd Mlekusch
Many safety regulations in the automotive engineering use impactor testing (e.g. FMVSS201 in the US; Pedestrian Protection, ECE-R21, proposal for EEVC WG13 in Europe) in the certification process. Through the increasing demand for very short development times virtual engineering has become an inevitable tool. We show a complete virtual development process for the Free-Motion-Headform (FMH) regulation (FMVSS201u), where we use a combination of self-developed and standard software. The process starts with the definition of the target-points, the possible and allowed positioning of the FMH, the detection of worst case angles, the automated generation of section cuts, the Finite-Elements (FE) analysis and the web based documentation of the results. Our self-developed tools play an important role in the FMH-positioning/worst case detection area as well as in the result analysis and documentation.
2004-03-08
Technical Paper
2004-01-0336
Naoki Kaneko, Masayuki Wakamatsu, Masanobu Fukushima, Shigeru Ogawa
Development of anti-whiplash technology is one of the hottest issues in the automotive safety field because of the frequent occurrence of rear impact accidents. We analyzed the whiplash mechanism and conducted a study to seek the optimized seat characteristics with BioRID II and MADYMO simulations. A parameter study was made to construct a conceptual theory to decrease NIC, Neck Injury Criteria, with the MADYMO model. As a result of the study, head restraint position and seatback stiffness were found to affect dummy movement and injury values. Applying the NIC mechanism and the influential parameters to the MADYMO model, the optimized seat characteristics for whiplash prevention were obtained.
2004-03-08
Technical Paper
2004-01-0342
David C. Viano, Chantal S. Parenteau
This paper provides an overview of rollover crash safety, including field crash statistics, pre- and rollover dynamics, test procedures and dummy responses as well as a bibliography of pertinent literature. Based on the 2001 Traffic Safety Facts published by NHTSA, rollovers account for 10.5% of the first harmful events in fatal crashes; but, 19.5% of vehicles in fatal crashes had a rollover in the impact sequence. Based on an analysis of the 1993-2001 NASS for non-ejected occupants, 10.5% of occupants are exposed to rollovers, but these occupants experience a high proportion of AIS 3-6 injury (16.1% for belted and 23.9% for unbelted occupants). The head and thorax are the most seriously injured body regions in rollovers. This paper also describes a research program aimed at defining rollover sensing requirements to activate belt pretensioners, roof-rail airbags and convertible pop-up rollbars.
2004-03-08
Technical Paper
2004-01-0350
Suzanne Tylko, Dainius Dalmotas
The responses of a 5th percentile female ATD in the driver and/or rear passenger positions of 56 crashes are described. The Transport Canada side impact programme consisted of LTV-to-car impacts, car-to-car impacts and IIHS barrier-to-car tests. The majority of the tests involved severe crash conditions for which the vehicles were not designed. The SID-IIs head, chest and abdominal responses were compared to determine the effects of the striking bullet geometry, the angle of impact, the impact point and the self-protective elements of the struck vehicle, including airbag technology and armrest designs. The SID-IIs head responses and deflection measures were sufficiently sensitive to discriminate between the various striking vehicles, crash configurations, airbag systems and armrest characteristics.
2004-03-08
Technical Paper
2004-01-1702
Alok Nanda, Gopikrishna Surisetty, Subhransu Mohapatra, Shaleena AD, Stephen Shuler, Frank Mooijman
This paper discusses a Design for Six Sigma (DFSS) based methodology for designing an injection molded bumper energy absorber to help meet vehicle pedestrian protection requirements. The development process is described, and an example is presented of its use in designing an injection molded energy absorber for a range of various vehicle styling parameters. First, an idealized set-up incorporating the car styling parameters critical for pedestrian protection requirements was developed. Then, the vehicle and Energy Absorber (EA) geometries were parameterized and a DFSS process was employed to investigate the design space using Finite Element Impact Analysis with a commercially available Lower Leg Form Impactor.
2004-03-08
Technical Paper
2004-01-0837
Zhiqing Cheng, Annette L. Rizer, Joseph A. Pellettiere
The performance of inflatable toepan padding for mitigating lower limb injuries was investigated. A rigid multi-body model was used to describe the scenario of an occupant in an automobile frontal crash with toepan intrusion. The emphasis was placed on the lower limb responses during impact. The interaction between the lower limbs and the inflatable toepan padding was described by the contact between the feet and the load distribution plate of the padding. Computational simulations were performed to analyze the effects of the controlled motion of this plate on the lower limb impact responses.
2004-03-08
Technical Paper
2004-01-0845
Lijian (Lee) Zhang, Liang Chen, Alicia Vertiz, Rana Balci
In 2002, NHTSA statistics indicate air bag deployments saved an estimated 1,500 lives; however, reports of occupants having serious or fatal injuries during air bag deployment appear low relative to the number of accidents with air bag deployments. To avoid air bag induced injuries, a variety of occupant sensing technologies are being developed. One of the critical logic deployment challenges faced by these technologies is whether the system can accurately determine if the occupant is in a posture or a position such that air bag deployment may result in an injury. To improve accuracy, it is necessary to understand what postures the occupants are likely to assume during a ride and how often. For this purpose, Delphi Corporation has conducted a survey to solicit opinions on the posture usage rate. With 560 responses, the frequencies for 29 sitting postures for adult passengers and 13 child postures or positions were estimated.
2004-03-08
Technical Paper
2004-01-0844
Raj S. Roychoudhury, James K. Conlee, Michael Best, David Schenck
Deployable or active knee bolsters are being introduced by many OEMs, primarily on the driver side, as an improvement to the fixed or passive knee bolsters. There are shortcomings with the fixed knee bolster and many of them can be overcome with a deployable knee bolster. Also the deployable knee bolster has a few other advantages that make it a critical restraint system component for reducing the occupant injury numbers in frontal impact crashes. With the latest revision of FMVSS208, vehicle manufacturers must now demonstrate occupant performance for a wide range of test conditions. OEMs are now required to evaluate the 5th percentile female and the 50th percentile male in both belted and unbelted scenarios. A wide range of crash conditions must also be evaluated, including rigid barriers, angled impacts and offset deformable barriers.
2004-03-08
Technical Paper
2004-01-0842
Jeffrey Augenstein, Elana Perdeck, James Stratton, Luis Labiste, Jerry Phillips, Jeffrey Mackinnon, Kennerly Digges, Richard Morgan, George Bahouth
The U.S. Department of Transportation-sponsored Crash Injury Research and Engineering Network (CIREN) program offers a reasonable look at the efficacy of second-generation air bags. This paper examines the data from the William Lehman Injury Research Center (WLIRC). The WLIRC data is a near census of crashes in the Miami-Dade region with occupants that appear to be severely injured. The percentage of deaths among trauma patients in the WLIRC data as a function of delta-V for first-generation air bags was higher than expected at lower delta-V's. There were nine driver fatalities at delta-V's of less than 20 mph (four involving short stature occupants, four with elderly occupants, and one due to significant intrusion and/or vehicle incompatibility). The data supported NHTSA's conclusion that first-generation air bags were too aggressive for occupants in close proximity to the deploying air bag and too aggressive for older persons.
2004-03-08
Technical Paper
2004-01-0840
Leonard Evans
This paper estimates that currently there are 250 million frontal airbags in the United States, which cost their owners $54 billion. In 2003 about 1.7 million of these deployed, 19,000 in fatal crashes in which over 8,000 vehicle occupants were killed sitting in seats protected by airbags that deployed. To date over 40,000 occupants have been killed sitting in seats protected by airbags that deployed. The growth of airbags increases the need to revisit the question of their cost-effectiveness, and also provides the data to do this. The cost-benefit comparison presented here relies on airbag effectiveness estimates and injury cost estimates published since 2000. Even after the deployment of 10 million airbags, their effect on injury risk remains uncertain, and the results presented here are sensitive to the injury-effectiveness values assumed.
2004-03-08
Technical Paper
2004-01-0852
Anne W. Snowdon, Jan Miller-Polgar, James Potvin, Giovanna Follo
Since 1976, Ontario has legislated mandatory use of vehicle restraints. However, trauma due to vehicle collisions continues to be a leading cause of death and injury in children. A survey design was used to examine parental knowledge and perceptions about safety systems for children. A biomechanical observation was conducted to document the physical and cognitive demands associated with safety restraint use. Results suggest that most children are generally seated in the correct restraint system; however transitions from forward facing car seats to booster seats and/or lap and shoulder belts were often done too early. In addition, physical demands of using safety restraints exceed most parents' ability to safety install and use safety restraints for their children.
2004-03-08
Technical Paper
2004-01-0850
Byungseok Kong, Jeonggil Park, Jongshik Bae
Hard panel types of invisible passenger-side airbag (IPAB) door system must be designed with a weakened area such that the airbag will deploy through the Instrument Panel (IP) in the intended manner, with no flying debris at any required operating temperature. At the same time, there must be no cracking or sharp edges in the head impact test (ECE 21.01). If the advanced-airbag with the big difference between high and low deployment pressure ranges are applied to hard panel types of IPAB door system, it becomes more difficult to optimize the tearseam strength for satisfying deployment and head impact performance simultaneously. We introduced the ‘Operating Window’ idea from quality engineering to design the hard panel types of IPAB door applied to the advanced-airbag for optimal deployment and head impact performance. To accurately predict impact performance, it is important to characterize the strain rate.
2004-03-08
Technical Paper
2004-01-0848
Patricia B. Fyhrie, Artie J. Martin
Panic braking can cause an “in-position” unbelted occupant to become “out-of-position.” Although the braking event dynamics and initial positioning of the occupant affect the final position at time of impact (if any), general trends are assumed. FMVSS208 now includes “out-of-position” (OOP) performance for Anthropomorphic Test Devices (ATDs) sizes twelve month to six year-old. Airbag suppression technologies currently address that range of OOP occupants. The objective of this study is to develop an approach to defining OOP test positions for the recently released 10 year old ATD and to assist restraint engineers in developing strategies to help reduce the risk of inflation induced injury to the larger out-of-position child. A series of panic brake tests was conducted with the 10 year-old Hybrid III to study panic braking kinematics. Antilock braking (ABS) generated the desired constant deceleration from high initial speeds (40 to 60mph) in three types of vehicles.
2004-03-08
Technical Paper
2004-01-1282
B. Wördenweber, H. Schäfer
The European Commission has set itself the ambitious target of cutting the figure of killed road users by half until the year 2010. In order to reach this goal it is absolutely necessary to check all possibilities and bring to bear measures with beneficial potential. Pedestrian protection is one such key point. With a voluntary agreement the European auto makers intend to comply with component safety tests similar to an EEVC proposal for the year 2005 and on. Beginning in 2010 the entire EEVC test procedure, or similar, will become obligatory. This paper lays down the requirements now arising for pedestrian protection and spells out the consequences for headlamp design.
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