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A finite element model of the human thorax was merged with a rigid body finite element implementation of the Hybrid III dummy (after removal of the Hybrid III thorax) and the combined model is used in simulations of an out of position driver during airbag deployment. Parameters related to injury, such as A-P thorax deformation, Viscous Criterion, rib stress distribution and strain in the thoracic contents are used to quantify the thoracic injury response. Initial driver position is varied to examine the relationship between distance from the airbag module and thoracic injury risk. The potential for injury mitigation through modulation of airbag inflation after initiation is also investigated. The utility of the combined model as an effective tool for the analysis of occupant kinematics and dynamics, examination of injury mechanisms, and optimization of restraint system design parameters is demonstrated.

Analysis of experimental acceleration time history data obtained from a thoracic instrumentation array has been performed. The data were generated under test conditions which include realistic frontal impacts in belt, air bag, and steering column systems and side impacts with rigid and padded door structures. Data from frontal and lateral pendulum impacts were also included. The results demonstrate that the instrumentation array captures sufficient information from the impact event to allow prediction of resulting thoracic trauma, defined either as thoracic AIS or total number of thoracic fractures, using a single function for each injury measure. Each function is universal in the sense that it is valid for all test modes and directions of impact. A strategy for developing a surrogate thorax to implement this injury predictive methodology is discussed and preliminary specifications are presented.

A series of 24 pregnant baboons was impacted under similar conditions. The only major variable was the difference in maternal restraint. The fetal death rate of 8.3% (1/12) among maternal animals impacted with three-point restraint was significantly different from five fetal deaths among 10 maternal animals impacted under lap belt restraint alone (p < 0.05). It is concluded that shoulder harness restraint should be recommended for use by pregnant travelers as being significantly more protective of fetal welfare when compared with lap belt restraint alone.

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.

With the widespread use of supplemental restraint systems (airbags), occasional rare injuries have occurred because of the force associated with these systems upon deployment. Recent case studies have demonstrated forearm fractures associated with airbag deployment. The present study was conducted to determine the tolerance of the human forearm under a dynamic bending mode. A total of 30 human cadaver forearm specimens were tested using three-point bending protocol to failure at 3.3 m/s and 7.6 m/s velocities. Results indicated significantly (p < 0.01) greater biomechanical parameters associated with males compared to females. The bending tolerance of the human forearm, however, was found to be most highly correlated to bone mineral density, bone area, and forearm mass. Thus, any occupant with lower bone mineral density and lower forearm geometry/mass is at higher risk. The mean failure bending moment for all specimens was 94 Nm.

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 series of twenty-nine tests was completed by conducting static deployment of side airbag systems to an out-of-position Hybrid III three-year-old dummy. Mock-ups (bucks) of vehicle occupant compartments were constructed. The dummy was placed in one of four possible positions for both door- and seat-mounted side airbag systems. When data from each type of position test were combined for the various injury parameters it was noted that the head injury criteria (HIC) were maximized for head and neck tests, and the chest injury parameters were maximized for the chest tests. For the neck injury parameters, however, all of the test positions produced high values for at least one of the parameters. The study concluded the following. Static out-of- position child dummy side airbag testing is one possible method to evaluate the potential for injury for worst-case scenarios. The outcome of these tests are sensitive to preposition and various measurements should be made to reproduce the tests.