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In this study a mathematical model was developed for the BIOSID dummy using the CAL3D simulation program. This model was correlated to the dummy impact response using pendulum tests on various body regions, and a side sled test. Favorable comparisons were achieved between the test results and the model responses. This model was then used for identifying optimal side airbag designs for a large car.

In this study the side airbag design for a large car was investigated. The assessment of the airbag efficacy was based on the TTI response of the SID. In general, large size cars have low TTI values to begin with due to their higher mass, stronger structure, and more spacing between the occupant and the door. The CALOPT optimization program was used to search the design space. We found that for this particular impact environment an airbag design with a high mass flow rate and a large vent resulted in the lowest TTI for the SID. The high mass flow rate enables the airbag to contact the dummy thorax early, which causes the dummy to begin to move away from the door before contact is established with the door. The large vent is necessary to avoid excessive force from the airbag during the dummy/airbag interaction. For the two inflators considered in this study it was found that the less aggressive inflator achieved a marginal reduction of 10% from the baseline TTI response.

A design strategy to simultaneously address the interaction of two restraint systems (airbag and belt) and two test conditions (FMVSS 208 and NCAP) was investigated. This design strategy was implemented using a math-based methodology for a midsize car passenger side restraint system. A number of airbag and safety belt design variables were examined and optimized resulting in improved NCAP performance for the midsize car used in the simulations. The result of this study shows that this math-based methodology could be used to project the potential performance of restraint systems for future vehicle programs. As is the usual recommended procedure for math-based results of highly complex nonlinear mechanical analyses of the type under consideration herein, test validation should be carried out prior to implementation of specific results in a production program.

A modeling technique was developed to simulate the door/occupant interaction in the FMVSS 214 test. The door components, including all the panels and the side airbag, were modeled by finite elements and the Side Impact Dummy was modeled by rigid segments with finite element contact surfaces. The DYNA3D finite element code and the CAL3D lumped-mass code were coupled together such that features in each program can be utilized in this modeling approach. A numerical scheme was developed to simulate the door crush due to the barrier impact to obtain the proper door interior stiffness. Material constants for the model were derived from the available test data. The model exhibited good correlation with the barrier test data for the dummy acceleration response. Using this model, potential countermeasures, including thorax padding, an armrest design, and a side airbag, were evaluated.

This study examines the combined effects of the passenger airbag and the seat belt on the occupant impact response. It was found that while an airbag is beneficial in reducing unbelted occupant injury, its restraint force is in general additive to that of the belts in a 30 MPH barrier impact and tends to increase belted occupant response numbers. A number of possible design strategies were discussed and the inherent performance trade-offs among various impact conditions were illustrated. Concepts for two types of Adaptive Restraint System (ARS) are discussed which might achieve even greater levels of occupant protection for both belted and unbelted occupants. For a belted occupant, these ARS designs have embedded logic to determine when and how to use an airbag and/or a belt under various impact conditions. These ARS designs try to utilize the combined strengths of the airbag and the seat belt systems. Possible design strategies for these systems were also discussed.