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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.

The heads of auto racing drivers and military pilots are usually not supported so that neck fatigue and injury can be a serious problem. A new Head And Neck Support (HANS) is being developed to reduce head motions and neck loads. The biomechanical performance of HANS has been evaluated by crash victim modeling with CAL 3-D and by impact sled testing with a Hybrid III dummy. Modeling and testing were conducted at 30 and 35 mph BEV and with acceleration directions from the front, right front, and right lateral. The model and test results show that head motions, neck loading, and the potential for neck injury are all significantly reduced with HANS compared to without HANS.

The purpose of this study is to provide an understanding of driver kinematics, injury mechanisms and spinal loads causing thoracolumbar spinal fractures in Indianapolis-type racing car drivers. Crash reports from 1996 to 2006, showed a total of forty spine fracture incidents with the thoracolumbar region being the most frequently injured (n=15). Seven of the thoracolumbar fracture cases occurred in the frontal direction and were a higher injury severity as compared to rear impact cases. The present study focuses on thoracolumbar spine fractures in Indianapolis-type racing car drivers during frontal impacts and was performed using driver medical records, crash reports, video, still photographic images, chassis accelerations from on-board data recorders and the analysis tool MADYMO to simulate crashes. A 50th percentile, male, Hybrid III dummy model was used to represent the driver.

A PC based interactive program was developed to simulate the unfolding and deploying process of a driver side airbag in the sagittal plane. The airbag was represented by a series of nodes. The maximum allowable stretch was less or equal to one between any two nodes. We assumed that the airbag unfolding was pivoted about folded points. After the completion of the unfolding process the airbag would begin to deploy. During the deploying process, two parameters were used to determine the nodal priority of the inflation. The first parameter was the distance between the instantaneous and final positions of a node. Nodes with longer distances to travel will have to move faster. We also considered the distance between the current nodal position and the gas inlet location. For a node closer to the gas inlet, we assumed that the deploying speed was faster. A graphical procedure was used to calculate the area of the airbag.

Studies have shown that dummies can be used to study various issues relating to an unrestrained driver's interaction with the steering system in frontal crashes. However, current dummies have limitations in simulation of car occupants and to assess the spectrum of injury types and mechanisms. Human cadaver subjects were used to study abdominal injury and “severe” steering wheel deformation as part of an evaluation of energy absorbing steering systems. A predominant factor influencing abdominal injury in these tests was the impact location of the lower rim, injury being associated with the rim aligned 50 mm below the xiphoid. The dummies developed approximately twice the impact force than the cadaver subjects in these severe tests with a noncompressible column, in part due to the chest of the dummies “bottoming” out on a rigid spine.

This paper builds on previous research on the development of a head displacement model for restrained occupants in frontal collisions. Physical and mathematical simulations were performed utilizing the 5th percentile female and 50th percentile male Hybrid III dummies to measure the effect of occupant size, seat belt system design and crash severity on resultant head displacement of occupants in frontal collisions. Sled and simulation accelerations ranged from 10 g to 20 g with delta-V's from 6.6 m/s to 10.0 m/s. Results indicate a difference between the 5th percentile female and 50th percentile male dummies. Preliminary assessment of head displacement as a function of occupant kinetic energy demonstrated good correlation.

This study identified the mechanical properties of ten cadaveric lumbar spines and two Hybrid III lumbar spines. Eight tests were performed on each specimen: tension, compression, anterior shear, posterior shear, left lateral shear, flexion, extension and left lateral bending. Each test was run at a displacement rate of 100 mm/sec. The maximum displacements were selected to approximate the loading range of a 50 km/h Hybrid III dummy sled test and to be non-destructive to the specimens. Load, linear displacement and angular displacement data were collected. Bending moment was calculated from force data. Each mode of loading demonstrated consistent characteristics. The load-displacement curves of the Hybrid III lumbar spine demonstrated an initial region of high stiffness followed by a region of constant stiffness.

A three-dimensional finite element model of a human neck has been developed in an effort to study the mechanics of cervical spine while subjected to impacts. The neck geometry was obtained from MRI scans of a 50th percentile male volunteer. This model, consisting of the vertebrae from C1 through T1 including the intervertebral discs and posterior elements, was constructed primarily of 8-node brick elements. The vertebrae were modeled using linear elastic-plastic materials, while the intervertebral discs were modeled using linear viscoelastic materials. Sliding interfaces were defined to simulate the motion of synovial facet joints. Anterior and posterior longitudinal ligaments, facet joint capsular ligaments, alar ligaments, transverse ligaments, and anterior and posterior atlanto-occipital membranes were modeled as nonlinear bar elements or as tension-only membrane elements. A previously developed head and brain model was also incorporated.

In a frontal automotive crash, the driver's foot is usually stepping on the brake pedal as an instinctive response to avoid a collision. The tensile force generated in the Achilles tendon produces a compressive preload on the tibia. If there is intrusion of the toe board after the crash, an additional external force is applied to the driver's foot. A series of dynamic impact tests using human cadaveric specimens was conducted to investigate the combined effect of muscle preloading and external force. A constant tendon force was applied to the calcaneus while an external impact force was applied to the forefoot by a rigid pendulum. Preloading the tibia significantly increased the tibial axial force and the combination of these forces resulted in five tibial pylon fractures out of sixteen specimens.

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.

Various types of padding have been used in side impact sled tests with cadavers. This paper presents a summary of performance of the padding used in NHTSA and WSU/CDC sled tests, and a summary of material properties of padding used in cadaveric sled tests. The purpose of this paper is to provide information on padding performance in cadavers, rather than optimum padding performance in dummies.

Heidelberg-type side impact sled tests were conducted using SID side impact dummies. These tests were run under similar conditions to a series of cadaveric sled tests funded by the Centers for Disease Control in the same lab. Tests included 6.7 and 9 m/s (15 and 20 mph) unpadded and 9 m/s padded tests. The following padding was used at the thorax: ARSAN, ARCEL, ARPAK, ARPRO, DYTHERM, 103 and 159 kPa (15 and 23 psi) crush strength paper honeycomb, and an expanded polystyrene. In all padded tests the dummy Thoracic Trauma Index, TTI(d) was below the value of 85 set by federal rulemaking (49 CFR, Part 571 et al., 1990). In contrast, cadavers in 9 m/s sled tests did not tolerate ARSAN 601 (MAIS 5) and 23 psi (159 kPa) paper honeycomb (MAIS 5), and 20 psi (138 kPa) Verticel™ honeycomb (MAIS 4), but tolerated 15 psi (103 kPa) paper honeycomb (average thoracic MAIS 2.3 in six tests).

Auto racing has been in vogue from the time automobiles were first built. With the dawn of modern cars came higher engine capacities; the speeds involved in these races and crashes increased as well. However, the advent of passive restraint systems such as the helmet, HANS (Head and Neck Support device), multi-point harness system, roll cage, side and frontal crush zones, racing seats, fire retardant suits, and soft-wall technology, have greatly improved the survivability of the drivers in high-speed racing crashes. Three left lateral crashes from Begeman and Melvin (2002), Case #LAS12, #IND14 and #99TX were used as inputs to the Wayne State Human Body Model (WSHBM) in a simulated racing buck. Twelve simulations with delta-v, six-point harness and shoulder pad as design variables were analyzed for the average maximum principal strain (AMPS) in the aorta. The average AMPS for the high-speed crashes were 0.1551±0.0172 while the average maximum pressure was 110.50±4.25 kPa.

Twelve side impact sled tests were performed using a horizontally accelerated sled and a Heidelberg-type seat fixture. In these tests the subject's whole body impacted a sidewall with one of three surface conditions: 1) a flat, rigid side wall, 2) a side wall with a 6″ pelvic offset, or 3) a flat, padded side wall. This series of runs provided a good test of how injury criteria perform under a variety of impact surface conditions. In this study thoracic injury criteria based on force, acceleration, compression, and velocity x compression (VC) were evaluated. Maximum compression and VCmax proved to be the best injury indicators in this series. Biomechanical response and injury tolerance are also presented.

PHASE I - A containment fixture was designed and manufactured to stabilize and preload isolated human pelves within a DYNATUP™ Drop Tower during simulated automotive side impact. The fixture was utilized during thirteen parametric tests aimed at determining boundary conditions which simulate inertial properties of whole cadavers during impacts of the isolated human pelvis. The resulting pelvic injuries (i.e., fractures) ranged from no fracture to complex acetabular fracture. These injuries were sustained with drop masses of 14.2-25.2 kg and impact velocities of 4.1-6.4 m/s. Peak force, measured during impact, ranged from 2.0-8.2 kN. PHASE II - Phrase II studies used nine additional human pelves to explored pelvis stiffness and pubis symphysis mobility under lateral impact to the greater trochanter. The containment device designed and tested in Phase I was utilized to stabilize and compressively preload the specimens during impact.

The primary purpose of this research was to generate a “linked set” of data between collision severity, occupant weight and collision-induced seat belt markings to assist in reconstruction of motor vehicle accidents. The secondary purpose was to establish a preliminary threshold of belt load to produce known collision-induced seat belt markings. Sled tests were performed utilizing Hybrid III 5th and 50th percentile crash test dummies. Sled accelerations ranged from 10.0 g to 23.6 g and Delta-V’s from 6.4 m/s to 11.3 m/s. Post-test inspections and photographs taken of the seat belts documented collision-induced markings on components such as the D-Ring, latch plate, webbing and stitching. Belt loads were analyzed to establish preliminary thresholds for the production of observable markings.

Injuries to the thorax and abdomen comprise a significant percentage of all occupant injuries in motor vehicle accidents. While the percentage of internal chest injuries is reduced for restrained front-seat occupants in frontal crashes, serious skeletal chest injuries and abdominal injuries can still result from interaction with steering wheels and restraint systems. This paper describes the design and performance of prototype components for the chest, abdomen, spine, and shoulders of the Hybrid III dummy that are under development to improve the capability of the Hybrid III frontal crash dummy with regard to restraint-system interaction and injury-sensing capability.

A 3-D finite element human head model has been developed to study the dynamic response of the human head to direct impact by a rigid impactor. The model simulated closely the main anatomical features of an average adult head. It included the scalp, a three-layered skull, cerebral spinal fluid (CSF), dura mater, falx cerebri, and brain. The layered skull, cerebral spinal fluid, and brain were modeled as brick elements with one-point integration. The scalp, dura mater, and falx cerebri were treated as membrane elements. To simulate the strain rate dependent characteristics of the soft tissues, the brain and the scalp were considered as viscoelastic materials. The other tissues of the head were assumed to be elastic. The model contains 6080 nodes, 5456 brick elements, and 1895 shell elements. To validate the head model, it was impacted frontally by a cylinder to simulate the cadaveric tests performed by Nahum et. al. (8).

Thirty-seven SID side impact sled tests were performed using a rigid wall and a padded wall with fourteen different padding configurations. The Thoracic Trauma Index (TTI) and Average Spine Acceleration (ASA) were measured in each test. TTI and ASA were evaluated in terms of their ability to predict injury in identical cadaver tests and in terms of their ability to predict the harm or benefit of padding of different crush strengths. SID ASA predicted the injury seen in WSU-CDC cadaver tests better than SID TTI. SID ASA predicted that padding of greater than 20 psi crush strength is harmful (ASA > 40 g's). SID TTI predicted that padding of greater than 20 psi crush strength is beneficial (TTI < 85 g's). SID TTI predicts the benefit of lower impact velocity. However, SID ASA appears more useful in assessing the harm or benefit of door padding or air bags.

A new three-dimensional human head finite element model, consisting of the scalp, skull, dura, falx, tentorium, pia, CSF, venous sinuses, ventricles, cerebrum (gray and white matter), cerebellum, brain stem and parasagittal bridging veins has been developed and partially validated against experimental data of Nahum et al (1977). A frontal impact and a sagittal plane rotational impact were simulated and impact responses from a homogeneous brain were compared with those of an inhomogeneous brain. Previous two-dimensional simulation results showed that differentiation between the gray and white matter and the inclusion of the ventricles are necessary in brain modeling to match regions of high shear stress to locations of diffuse axonal injury (DAI). The three-dimensional simulation results presented here also showed the necessity of including these anatomical features in brain modeling.