Restraint Robustness in Frontal Crashes 2007-01-1181

The protection of a vehicle occupant in a frontal crash is a combination of vehicle front structural design and occupant restraint design. Once chosen and manufactured, these design features must interact with a wide variety of structural characteristics in potential crash partners. If robust, the restraint design will provide a high level of protection for a wide variety of crash conditions. This paper examines how robust a given restraint system is for occupant self-protection and how frontal design can improve the restraint performance of potential crash partners, thus improving their restraint robustness as well.

To examine restraint robustness in self protection, the effect of various vehicle deceleration characteristics on occupant injury potential is investigated for a given restraint design. A MADYMO model of a 1996 Taurus interior and its restraint system with a Hybrid III 50th percentile male dummy are simulated and subjected to 650 crash pulses taken during 25 years of U.S. New Car Assessment Program (NCAP) testing, thus reflecting a wide range of frontal stiffness and corresponding crash pulses. The injury measures of the dummies in the simulations, with only the deceleration pulse changed, are compared to examine the robustness of the given occupant restraint system. Average deceleration is shown to have a high correlation with the MADYMO injury outcomes and thus provides an overall indication of structural performance in robust self protection.

In order to relate self protection to more detailed structural characteristics and robust compatibility performance, the average deceleration from the NCAP vehicles are analyzed with respect to the vehicle design metrics of weight, dynamic stiffness, dynamic crush, and the compatibility metric of energy stiffness. Of these, dynamic crush is shown to highly correlate with average deceleration in the NCAP vehicles, and thus self protection injury measures. Conversely, energy stiffness is shown to be nearly independent of average deceleration, thus opening the way to design for both high self protection and effective fleet compatibility.