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.

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.

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.

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.

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.

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.

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.

NHTSA conducted seventy-six side impact FMVSS No. 214 compliance tests from 1994 through 1997. The compliance tests are nearly right angle side impacts with low longitudinal components of change of velocity (Δv). Frontal air bag deployments were found to have occurred for 34% of the driver bags and 32% of the front passenger bags in these compliance-tested passenger cars. In 1997, NHTSA began testing passenger cars 'in side impact in the New Car Assessment Program (NCAP). The NCAP crash tests are conducted at a higher speed than the compliance tests. The cars in the NCAP side impact tests also had low longitudinal components of Δv. Approximately 40% of the twenty-six passenger cars tested in the 1997 Side Impact NCAP had their frontal air bags deploy. Real world crash data were examined to determine if frontal air bags are deploying in right angle side impacts on the roads of the US.

Since 1990, the National Highway Traffic Safety Administration (NHTSA) implemented a dynamic side impact compliance test. This compliance test, Federal Motor Vehicle Safety Standard (FMVSS) No. 214, is a nearly right angle side impact in which the striking vehicle moves at 53.6 kmph into the struck vehicle. In 1997, NHTSA began testing passenger cars in side impact in the New Car Assessment Program (NCAP). In the USA NCAP side impact, the striking vehicle is towed at a 8 kmph higher speed than in the compliance test. An analysis has begun on the data from the first NCAP side impact tests, thirty-two in number. In the crashes, accelerometers were installed in the door and door frames of the struck vehicle. Using the accelerometers on the vehicle structure and in the side impact dummy, the crash event was investigated. One tool used in the investigation was the velocity-versus-time diagram.

A three-dimensional finite element model of the Hybrid III dummy head-neck complex was created to simulate the Amended Part 572 Head-Neck Pendulum Compliance Test, of the Code of Federal Regulations. The model consisted of a rigid head and five circular aluminum disks joined together by butyl elastomer rubber. Contact surfaces were defined to allow the anterior neck to separate upon an application of extension moments. Two mounting positions, one for flexion and the other one for extension, were used to simulate the head-neck calibration tests. An explicit finite element code PAM-CRASH was utilized to simulate the model dynamic responses. Simulation results were compared to experimental data obtained from First Technology Safety Systems Inc. Model predictions agreed well in both flexion and extension. This model can be used to study the head-neck biomechanics of the existing dummy as well as in the development of new dummies.

Sixty-three simulated frontal impacts using cadaveric specimens were performed to examine and quantify the performance of various contemporary automotive restraint systems. Test specimens were instrumented with accelerometers and chest bands to characterize their mechanical responses during the impact. The resulting thoracic injury severity was determined using detailed autopsy and was classified using the Abbreviated Injury Scale. The ability of various mechanical parameters and combinations of parameters to assess the observed injury severities was examined and resulted in the observation that belt restraint systems generally had higher injury rates than air bag restraint systems for the same level of mechanical responses. To provide better injury evaluations from observed mechanical parameters without prior knowledge of what restraint system was being used, a dichotomous process was developed.

A study of frontal collisions using the NASS data base showed that there were four times as many arm injuries to belt restrained drivers who had an air bag deploy than for the drivers who were simply belted. By far, the distal forearm/hand was the most commonly injured region. Hard copy review identified two modes of arm injury related to the deploying air bag: 1) The arm is directly contacted by the air bag module and/or flap cover, and 2) The arm is flung away and contacts an interior car surface. Based on the field studies, a mechanical device called the Research Arm Injury Device (RAID) was fabricated to assess the aggressivity of air bags from different manufacturers. Results from static air bag deployment tests with the RAID suggested that the RAID was able to clearly distinguish between the aggressive and non-aggressive air bags. Maximum moments ranging between 100 Nm and 650 Nm, and hand fling velocity ranging between 30 and 120 km/h were measured on the RAID in these tests.

After a rear end impact, various clinical symptoms are often seen in car occupants (e.g. neck stiffness, strain, headache). Although many different injury mechanisms of the cervical spine have been identified thus far, the extent to which a single mechanism of injury is responsible remains uncertain. Apart from hyperextension or excessive shearing, a compression of the cervical spine can also be seen in the first phase of the impact due to ramping or other mechanical interactions between the seat back and the spine. It is hypothesized that this axial compression, together with the shear force, are responsible for the higher observed frequency of neck injuries in rear end impacts versus frontal impacts of comparable severity. The axial compression first causes loosening of cervical ligaments making it easier for shear type soft tissue injuries to occur.