Search Results

Throughout the first decade of the twenty first century, large improvements in occupant safety have been made in NASCAR®'s (National Association for Stock Car Auto Racing, Inc) race series. Enhancements to the occupant restraint system include the development and implementation of head and neck restraints, minimum performance requirements for belts and seats and the introduction of energy absorbing foam are a few highlights, among others. This paper discusses nineteen sled tests used to analyze hypothesized improvements to restraint system mounting geometry. The testing matrix included three sled acceleration profiles, three impact orientations, two Anthropomorphic Test Device (ATD) sizes as well as the restraint system design variables.

This study examines the static pressure distribution under both width belts in the shoulder and the pelvis of 15 volunteer subjects. The subjects applied the belt loads to themselves through a lever and pulley system. The configuration of the belts simulated the typical arrangement of a six-point belted upright-seated racing driver. The pressure distribution between the belt and the volunteer's body was determined and recorded with Tek-Scan pressure sensing grids. The paper presents the results of the measurements by comparing the actual area of significant loading beneath the two widths and materials of both lap and shoulder belts. In, general, there no significant increase in loaded area for the wider belts.

Measurement of chest compression is vital to properly assessing injury risk for restraint systems. It directly relates chest loading to the risk of serious or fatal compression injury for the vital organs protected by the rib cage. Other measures of loading such as spinal acceleration or total restraint load do not separate how much of the force is applied to the rib cage, shoulders, or lumbar and cervical spines. Hybrid III chest compression is biofidelic for blunt impact of the sternum, but is “stiff” for belt loading. In this study, an analysis was conducted of two published crash reconstruction studies involving belted occupants. This provides a basis for comparing occupant injury risks with Hybrid III chest compression in similar exposures. Results from both data sources were similar and indicate that belt loading resulting in 40 mm Hybrid III chest compression represents a 20-25% risk of an AIS≥3 thoracic injury.

Recent action by some racecar sanctioning bodies making head/neck restraint use mandatory for competitors has resulted in a number of methods attempting to provide head/neck restraint. This paper evaluates the performance of a number of commercially available head/neck restraint systems using a stock car seating configuration and a realistic stock car crash pulse. The tests were conducted at an impact angle of 30 degrees to the right, with a midsize male Hybrid III anthropomorphic test device (ATD) modified for racecar crash testing. A six-point latch and link racing harness restrained the ATD. The goal of the tests was to examine the performance of the head/neck restraint without the influence of the seat or steering wheel. Three head/neck restraint systems were tested using a sled pulse with a 35 mph (56 km/h) velocity change and 50G peak deceleration. Three tests with three samples of each system were performed to assess repeatability.

This study is an extension of previous work on driver air bag deployment loads which used the mid-size male Hybrid Ill dummy. Both small female and mid-size male Hybrid Ill dummies were tested with a range of near-positions relative to the air bag module. These alignments ranged from the head centered on the module to the chest centered on the module and with various separations and lateral shifts from the module. For both sized dummies the severity of the loading from the air bag depended on alignment and separation of the dummy with respect to the air bag module. No single alignment provided high responses for all body regions, indicating that one test at a typical alignment cannot simultaneously determine the potential for injury risk for the head, neck, and torso. Based on comparisons with their respective injury assessment reference values, the risk of chest injury appeared similar for both sized dummies.

The purpose of this paper is to establish injury assessment reference values specific to the CRABI 6-Month infant dummy for use in evaluating the interaction of rear-facing infant restraints with a deploying passenger airbag. The available literature on the biomechanics of child injury and mechanical response and the results of impact tests with various child and infant dummies are reviewed and summarized. Estimations of the injury assessment reference values for use with the CRABI 6-Month dummy are made using scaling techniques based on the principles of dimensional analysis and dummy test data from infant restraint tests under conditions where injuries are not likely to occur. The information developed in this report will allow the assessment of injury potential in tests of the interaction of passenger airbags with rear-facing infant restraints. This issue is of particular importance to vehicles with only front seats, such as pickup trucks and sport vehicles.

It is well known that the ability of the human body to withstand trauma is a function of its inherent strength, i.e., the strength of the bones and soft tissues. Yet, the properties of the bones and tissues change as a function of the individual's age. In this paper age effects on thoracic injury tolerances are studied by analyzing the mechanical properties of human bones and soft tissues and by examining experimental results found in the literature of thoracic impact tests to human cadavers. This work suggests that the adult age range can be divided into three age groups. Using piece-wise linear regression analyses, it has been determined that the reduction in injury tolerance from the “young” age group to the “elderly” group is approximately 20% under blunt frontal impact loading conditions and is as much as 70% under belt loading conditions.

At the 2002 MSEC, we presented a paper on the sled test evaluation of racecar head/neck restraint performance (Melvin, et al. 2002). Some individuals objected to the 3 msec clip filtering procedures used to eliminate artifactual spikes in the neck tension data for the HANS® device. As a result, we are presenting the same test data with the spikes left in the neck force data to reassure those individuals that these spikes did not significantly affect the results and conclusions of our original paper. In addition we will add new insights into understanding head/neck restraint performance gained during two more years of testing such systems. This paper re-evaluates the performance of three commercially available head/neck restraint systems using a stock car seating configuration and a realistic stock car crash pulse. The tests were conducted at an impact angle of 30 degrees to the right, with a midsize male Hybrid III anthropomorphic test device (ATD) modified for racecar crash testing.

This paper discusses the development of adequate criteria and evaluation methods for seat belt restraint design. These criteria should include the effect of seat belts in abdominal injury as well as head injury. It is concluded that belt load limiters and energy-absorbing devices should limit head-to-vehicle contact, ensure that the lap belt maintains proper contact with the bony pelvic girdle, and limit the belt loads. Studies are made of pulse shape and belt fabrics. Currently available mathematical models are used for the studies included in the paper.

Data on towaway accidents involving 1973- and 1974-model American passenger cars were collected according to a systematic sampling plan in order to measure 1974 restraint system performance. The data on 5,138 drivers and right front passengers were collected by three organizations: Calspan Corporation, Highway Safety Research Institute, and Southwest Research Institute. Analysis of the data showed that the 1974 ignition interlock system increased full restraint system usage by a factor of 10 over 1973 cars. The 1974 full restraint system (lap and upper-torso belts) also demonstrated a greater reduction in severe injuries (AIS≥2) than the 1973 lap-belt-only system. Paradoxically, little reduction in 1974-model severe injuries was found when the two model years were compared, although no attempt was made to control for confounding factors in the accident cases.

Detailed investigations of automobile crashes in which children under 10 years old were passengers were carried out. The purpose of this study was to investigate the injury patterns of restrained and unrestrained children and to assess the performance of child restraint systems in real world crashes. Crashes which occurred mainly in Washtenaw and Oakland counties of the state of Michigan were surveyed. A total of 348 vehicle crashes involving 494 children less than 10 years old were identified. Forty eight crashes involving 63 children were selected for in-depth investigation. 37% of the children in the investigated cases were restrained by an adult lap belt or a child restraint. It was found that only 4.7% of the children in the overall sample were restrained. Both adult seat belts and child restraints (when used) were found to be effective in reducing injuries in crashes. Head and facial injuries were found to be the most common form of injury to children.

The general objective of the whole-Body Response (WBR) research program was to generate data on the kinematics and response of human surrogates in a realistic automobile impact environment. The program used a test configuration consisting of an idealized hard seat representation of a car seat with a three-point harness restraint system. Three different severity levels of crash test conditions were used. The human surrogates tested in this program were fifteen male cadavers*, a Hybrid II (Part 572) Anthropomorphic Test Device and a Hybrid III ATD recently developed by General Motors. In addition, mathematical simulations of the response and kinematics of a 50th percentile male occupant were performed at the three levels of crash severity, using the MVMA Two-Dimensional Crash Victim Simulator.

A series of 16 sled impact tests was conducted at the Highway Safety Research Institute sled facility to evaluate the effectiveness of restraint devices and systems currently being used to transport school-bus and wheelchair-seated handicapped children. A sled impact pulse of 20 m.p.h. and 16 G's was used for all tests. Eight tests involved wheelchairs in forward-facing and side-facing orientations for head-on and 33-degree oblique impacts. Another eight tests involved forward-facing bus seats for head-on and 33-degree oblique impacts. The results generally point out the ineffectiveness of many currently used devices and systems for protecting the child in a bus collision. In six of the eight bus seat tests the dummy's head struck the back of the bus seat in front. This was primarily because of a lack of upper-torso restraint.

A sensor is described that can continuously monitor intrusion and associated pressure in the abdominal area of a child dummy. A prototype device was installed in a Part 572 3-year-old dummy and used in a series of dynamic tests with a variety of child restraint systems. The sensor was able to discriminate among different restraint configurations over a range of 0 to 55 psi. The performance differences observed, in terms of peak pressures and pressure-time waveforms, were further evaluated in relation to dummy kinematics and restraint system construction.

This paper presents the results of a series of over 30 impact sled simulations of racing car frontal crashes conducted as part of the GM Motorsports Safety Technology Research Program. A Hyge™ impact sled fitted with a simulated racing car seat and restraint system was used to simulate realistic crash loading with a mid-size male Hybrid III dummy. The results of tests, in the form of measured loads, displacements, and accelerations, are presented and comparisons made with respect to the levels of these parameters seen in typical passenger car crash testing and to current injury threshold values.

Biomechanical analysis of Indy car crashes using on-board impact recorders (Melvin et al. 1998, Melvin et al. 2001) indicates that Indy car driver protection in high-energy crashes can be achieved in frontal, side, and rear crashes with severities in the range of 100 to 135 G peak deceleration and velocity changes in the range of 50 to 70 mph. These crashes were predominantly single-car impacts with the rigid concrete walls of oval tracks. This impressive level of protection was found to be due to the unique combination of a very supportive and tight-fitting cockpit-seating package, a six-point belt restraint system, and effective head padding with an extremely strong chassis that defines the seat and cockpit of a modern Indy car. In 2000 and 2001, a series of fatal crashes in stock car racing created great concern for improving the crash protection for drivers in those racecars.

NASA is developing a new crewed vehicle and desires a lower risk of injury compared to automotive or commercial aviation. Through an agreement with the National Association of Stock Car Auto Racing, Inc. (NASCAR®), an analysis of NASCAR impacts was performed to develop new injury assessment reference values (IARV) that may be more relevant to NASA's context of vehicle landing operations. Head IARVs associated with race car impacts were investigated by analyzing all NASCAR recorded impact data for the 2002-2008 race seasons. From the 4015 impact files, 274 impacts were selected for numerical simulation using a custom NASCAR restraint system and Hybrid III 50th percentile male Finite Element Model (FEM) in LS-DYNA. Head injury occurred in 27 of the 274 selected impacts, and all of the head injuries were mild concussions with or without brief loss of consciousness. The 247 noninjury impacts selected were representative of the range of crash dynamics present in the total set of impacts.