Search Results

This investigation addresses and evaluates: (1) belted drivers in frontal crashes; (2) crashes divided into low, medium, and high severity; (3) air-bag-equipped passenger vehicles separated into either model years 1985 - 1997 (with airbags) or model years 1998 - 2008; (4) rate of Harm as a function of crash severity and vehicle model year; and (5) injury patterns associated with injured body regions and the involved physical components, by vehicle model year. Comparisons are made between the injury patterns related to drivers seated in vehicles manufactured before 1998 and those manufactured 1998 or later. The purpose of this comparative analysis is to establish how driver injury patterns may have changed as a result of the introduction of more recent safety belt technology, advanced airbags, or structural changes.

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.

For children seated next to the struck side, real-world crash outcome was determined for the rear-seat of passenger vehicles over the entire range of side impact crash severities. The method was first to calculate the actual risk for an occupant based on field data. The data sources were non-rollover, tow-away crashes from the 1997 - 2009 National Automotive Sampling System. By limiting the struck passenger vehicle to model year 1985 or newer, field data were identified for a total of 588 children. In all crashes, the child was seated in the rear-seat area on the struck side of the passenger vehicle. A matrix of MADYMO model simulations calculated the response of child dummies over the entire range of the field data. Age-dependent, moderate-to-serious (AIS ≥ 2) injury risk curves were derived and evaluated for children in side impact. Risks to the children were calculated by combining the derived child risk curves with the MADYMO model simulations.

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.

Accident cases are examined to determine the injury mechanism for foot/ankle moderate and greater injuries in vehicle crashes. The authors examine 480 in-depth cases from the National Accident Sampling System for the years 1979 through 1987. An injury mechanism - a description of how the foot/ankle physically interacted with the interior of the vehicle - is assigned to each of the injured occupants. For the accidents in which the 480 occupants were injured, the more prominent types of vehicle collisions are characterized.

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.

A common injury type among foot and ankle injury is the Lisfranc trauma, or injury to the forefoot. The Lisfranc injury indicates abnormal alignment of the tarsal-metatarsal joints with the loss of their normal spatial relationships. In 2003, Smith completed a laboratory study of this injury mechanism at Wayne State University [1, 2]. He found Lisfranc trauma was correlated with impact force to the forefoot. He proposed a probability of injury function that is based on the applied force to the forefoot. This study examined the instrumentation in the foot of the dummies in the USA New Car Assessment Program (NCAP) and Insurance Institute of Highway Safety (IIHS) frontal crashes. Nineteen different passenger vehicles representing four different vehicle classes were selected based mostly on a large presence in the USA vehicle fleet. Both NCAP and IIHS crashed these nineteen makes and models.

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.

The purpose of this paper is to assess the vehicle environment that a child occupant, between the ages of seven and thirteen years old, is exposed to in a real world crash. The focus of analysis is on those child occupants that are seated at the struck side in a lateral collision. This study was based on data extracted from the National Automotive Sampling System / Crashworthiness Data System (NASS/CDS) between years 1991-2006. Analysis was based upon the evaluation of the projected consequence of injury to the child occupants. The societal costs generated as a result of occupant injuries were quantified. The societal cost, or Harm, acts as a measure of consequence of occupant exposure to the vehicle environment, when involved in a collision. The Harm was determined as a function of ΔV, principal direction of force, vehicle extent of damage, the pattern of damage to the vehicle, and the magnitude of intrusion based on the occupant seating position.

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.

Since 1994, the New Car Assessment Program (NCAP) of the National Highway Traffic Safety Administration (NHTSA) has compiled upper neck loads for the belt and air bag restrained 50th percentile male Hybrid III dummy. Over five years from 1994 to 1998, in frontal crash tests, NCAP collected upper neck data for 118 passenger cars and seventy-eight light trucks and vans. This paper examines these data and attempts to assess the potential for neck injury based on injury criteria included in FMVSS No. 208 (for the optional sled test). The paper examines the extent of serious neck injury in real world crashes as reported in the National Automotive Sampling System (NASS). The results suggest that serious neck injuries do occur at higher speeds for crashes involving occupants restrained by belts in passenger cars.

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.

This study assessed the primary involved physical components attributed to the head and face injuries of child occupants seated directly adjacent to the stuck side of a vehicle in a side impact collision. The findings presented in this study were based upon analysis of the National Automotive Sampling System/Crashworthiness Data System (NASS/CDS) for the years 1993–2007. Injury analysis was conducted for those nearside child occupants aged between 1–12 years-old. The involved children were classified as toddler-type, booster-type, or belted-type occupants. These classifications were based upon the recommended restraint system for the occupant. Injury mechanisms were assessed for the child occupants in each of the three groups. A detailed study of NASS/CDS cases was conducted to provide a greater understanding of the associated injury mechanisms.

Lower extremity injuries in frontal automotive crashes usually occur with footwell intrusion where both the knee and foot are constrained. In order to identify factors associated with tibial shaft injury, a series of numerical simulations were conducted using a finite element model of the whole human body. These simulations demonstrated that tibial mid-shaft injuries in frontal crashes could be caused by an abrupt change in velocity and a high rate of footwell intrusion.

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.

A nonlinear foam was added to a previously created three-dimensional finite element model of the Hybrid III dummy chest which consisted of six steel ribs, rib damping material, the sternum, a spine box and a pendulum. Two standard calibration pendulum impact tests for a Hybrid III dummy chest were used to validate the new model. An explicit finite element analysis code PAM-CRASH was utilized to simulate the dynamic process. At impact velocities of 6.7 m/s and 4.3 m/s, the force and deflection time history as well as the force-deflection plots showed good agreement between model predictions and calibration data. Peak strains also agreed well with experimental data.

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.

The research question investigated in this study is what are the key attributes of foot and ankle injury in the between-rail frontal crash? For the foot and ankle, what was the type of interior surface contacted and the type of resulting trauma? The method was to study with in-depth case reviews of NASS-CDS cases where a driver suffered an AIS=2 foot or ankle injury in between-rail crashes. Cases were limited to belted occupants in vehicles equipped with air bags. The reviews concentrated on coded and non-coded data, identifying especially those factors contributing to the injuries of the driver's foot/ankle. This study examines real-world crash data between the years 1997-2009 with a focus on frontal crashes involving 1997 and later model year vehicles. The raw data count for between-rail crashes was 732, corresponding to 227,305 weighted, tow-away crashes.