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This paper describes the results of a project to develop a MADYMO occupant model for predicting thoracolumbar (TL) spine injuries during frontal impacts in the Indianapolis-type racing car (ITRC) environment and to study the effect of seat back angle, shoulder belt mounting location, leg hump, and spinal curvature on the thoracolumbar region. The newly developed MADYMO Race Car Driver Model (RCDM) is based on the Hybrid III, 50th percentile male model, but it has a multi-segmented spine adapted from the MADYMO Human Facet Model (HFM) that allows it to predict occupant kinematics and intervertebral loads and moments along the entire spinal column. Numerous simulations were run using the crash pulses from seven real-world impact scenarios and a 70 G standardized crash pulse. Results were analyzed and compared to the real-world impacts and CART HANS® model simulations.

The objective of this work was to evaluate a new tool for assessing brain injury. Many race car drivers have suffered concussion and other brain injuries and are in need of ways of evaluating better head protective systems and equipment. Current assessment guidelines such as HIC may not be adequate for assessing all scenarios. Finite element models of the brain have the potential to provide much better injury prediction for any scenario. At a previous Motorsports conference, results of a MADYMO model of a racing car and driver driven by 3-D accelerations recorded in actual crashes were presented. Model results from nine cases, some with concussion and some not, yielded head accelerations that were used to drive the Wayne State University Head Injury Model (WSUHIM). This model consists of over 310,000 elements and is capable of simulating direct and indirect impacts. It has been extensively validated using published cadaveric test data.

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.

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.

The close-fitting cockpit of the modern Indy car single seat race car has the potential to provide a high level of head and neck impact protection in rear and side impacts. Crash investigation has shown that a wide variety of materials have been used as the padding for these cockpits and, as a result, produced varying outcomes in crashes. Additionally, these pads have not always been positioned for optimal performance. The purpose of this study was to investigate the head impact performance of a variety of energy-absorbing padding materials under impact conditions typical of Indy car rear impacts and to identify superior materials and methods of improving their performance as race car head pads. An extensive series of tests with the helmeted Hybrid III test dummy head and neck on an impact mini-sled was conducted to explore head padding concepts.

This paper describes the results of an ongoing project in the GM Motorsports Safety Technology Research Program to investigate Indianapolis-type (Indy car) race car crashes using an on-board impact recorder as the primary data collection tool. The paper discusses the development of specifications for the impact-recording device, the selection of the specific recorder and its implementation on a routine basis in Indy car racing. The results from incidents that produced significant data (crashes with peak decelerations above 20 G) during the racing seasons from 1993 through the first half of 1998 are summarized. The focus on Indy car crashes has proven to provide an almost laboratory-like setting due to the similarity of the cars and to the relative simplicity of the crashes (predominantly planar crashes involving single car impacts against well-defined impact surfaces).

Two-dimensional film analysis was conducted to study the kinematics of the head and neck of 17 restrained human volunteers in 24 frontal impacts for acceleration levels from 6g to 15g. The trajectory of the head center of gravity relative to upper torso reference points and the rotation of head and neck relative to the lower torso during the forward motion phase were of particular interest. The purpose of the study was to analyze the head-neck kinematics in the mid-sagittal plane for a variety of human volunteer frontal sled tests from different laboratories using a common analysis method for all tests, and to define a common response corridor for the trajectory of the head center-of-gravity from those tests.

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.

A two-dimensional finite element model of the head of a rhesus monkey was built to simulate the head acceleration experiments done by Gennarelli and his colleagues. The purposes of the study were to better understand the mechanisms of traumatic subdural hematoma and to estimate its threshold of occurrence. The brain was treated as an isotropic homogeneous elastic material with and without structural damping and the skull was treated as a rigid shell. To simulate Abel et al.'s (1) experiments, the head was subjected to an enforced forward rotation around the neck. The loading had an initial acceleration phase followed by deceleration. During both acceleration and deceleration phases, high shear stress (and thus strain) occurred at the vertex, where the parasagittal bridging veins are located. The deformation of the bridging vein depended on its orientation relative to the direction of impact.

Injury and disability associated with head (brain), neck (spinal cord) and facial injury account for 61.7% of the total societal Harm in the most recent estimate of motor-vehicle related crash injuries. This paper discusses the need for accurate information on translational and rotational acceleration of the head as the first step in critiquing the Head Injury Criterion (HIC) and other injury predictive methods, and developing a fuller understanding of brain and spinal cord injury mechanisms. A measurement system has been developed using linear accelerometers to accurately determine the 3D translational and rotational acceleration of the Hybrid III dummy head. Our concept has been to use the conventional triaxial accelerometer in the dummy's head to assess translational acceleration, and three rows of in-line linear accelerometers and a least squares analysis to compute statistical best-fits for the rotational acceleration about three orthogonal axes.

Two series of impacts to the head in the superior-inferior direction using 19 unembalmed cadavers are reported. The first series of five tests was aimed at generating kinematic and dynamic response to sub-injurious impacts for the purpose of defining the mechanical characteristics of the undamaged head-neck-spine system in the S-I direction. The second series of fourteen tests was intended to define injury tolerance levels for a selected subject configuration. A 10-kg impactor was used to deliver the impact to the crown at a nominal velocity of 8 m/s for the first series, and between 7 and 11 m/s for the second series. Measurements made in the first series include the impact velocity, force, and energy, the head three-dimensional kinematics, forces and moments at the occipital condyles, and accelerations of the T1, T6, and T12 vertebrae. Impact impedance curves were also generated.

Multiple axial knee impacts and/or a single lateral pelvis impact were performed on a total of 19 cadavers. The impacting surface was padded with various materials to produce different force-time and load distribution characteristics. Impact load and skeletal acceleration data are presented as functions of both time and frequency in the form of mechanical impedance. Injury descriptions based on gross autopsy are given. The kinematic response of the pelvis during and after impact is presented to indicate the similarities and differences in response of the pelvis for various load levels. While the impact response data cannot prescribe a specific tolerance level for the pelvis, they do indicate variables which must be considered and some potential problems in developing an accurate injury criterion.

The purpose of this literature review was to determine areas of automotive injury information that may add to knowledge of injury type, frequency, severity, and cause. This paper is a review of the literature concentrating on the period between 1965 and present. Literature on car, van, or 1ight truck occupants has been reviewed for injury frequencies, types, and locations. Current experimental biomechanical articles are also included. A search was made for descriptions of injury frequency, restraint effectiveness, and the causes of specific injuries. Medical and engineering journals, texts, and books were reviewed. For convenience, this report is divided into sections by body region with an overview introduction on the anatomy of the specific region.

The response of the head to impact in the posterior-to-anterior direction was investigated with live anesthetized and post-mortem primates.* The purpose of the project was to relate animal test results to previous head impact tests conducted with cadavers (reported at the 21st Stapp Car Crash Conference (1),** and to study the differences between the living and post-mortem state in terms of mechanical response. The three-dimensional motion of the head, during and after impact, was derived from experimental measurements and expressed as kinematic quantities in various reference frames. Comparison of kinematic quantities between subjects is normally done by referring the results to a standard anatomical reference frame, or to a predefined laboratory reference frame. This paper uses an additional method for describing the kinematics of head motion through the use of Frenet-Serret frame fields.

Knee bolsters on the lower instrument panel have been designed to control occupant kinematics during sudden deceleration. However, a wide variability in car occupant anthropometry and choice of seating posture indicates that lower-extremity contacts with the impingement bolster could predominantly load the flexed leg through the knee (acting through the femur) or through the tibia (acting through the knee joint). Potential injuries associated with these types of primary loading may vary significantly and an understanding of potential trauma mechanisms is important for proper occupant restraint.

A versatile high-speed cineradiographic system developed in the Biomechanics Department of The University of Michigan's Highway Safety Research Institute has recently been completed, for application to human injury and tolerance and occupant protection research. This system consists of a high-speed motion picture camera which views a 2-inch diameter output phosphor of a high gain 4-stage, magnetically focussed image intensifier tube, gated on and off synchronously with shutter pulses from the motion picture camera. A fast lens optically couples the input photocathode of the image intensifier tube to x-ray images produced on a fluorescent screen by a d-c x-ray generator.

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.

This paper is a brief review of the complex subject of human injury mechanisms and impact tolerance. Automotive accident-related injury patterns are briefly described and the status of knowledge in the biomechanics of trauma of the head, neck, chest, abdomen and extremities is discussed.

This paper presents the results of direct impact tests and driving point impedance tests on the legs of seated unembalmed human cadavers. Variables studied in the program included impactor energy and impact direction (axial and oblique). Multiple strain gage rosettes were applied to the bone to determine the strain distribution in the bone. The test results indicate that the unembalmed skeletal system of the lower extremities is capable of carrying significantly greater loads than those determined in tests with embalmed subjects (the only similar data reported in the present literature). The strain analysis indicated that significant bending moments are generated in the femur with axial knee impact. The results of the impedance tests are used to characterize the load transmission behavior of the knee-femur-pelvis complex, and the impact test results are combined with this information to produce suggested response characteristics for dummy simulation of knee impact response.

This paper describes the development of an improved neck simulation that can be adapted to current anthropometric dummies. The primary goal of the neck design is to provide a reasonable simulation of human motion during impact while maintaining a simple, rugged structure. A synthesis of the current literature on cervical spine mechanics was incorporated with the results of x-ray studies of cervical spine mobility in human volunteers and with the analysis of head-neck motions in human volunteer sled tests to provide a background for the design and evaluation of neck models. Development tests on neck simulations were carried out using a small impact sled. Tests on the final prototype simulation were also performed with a dummy on a large impact sled. Both accelerometers and high-speed movies were used for performance evaluation.