Search Results

The purpose of this study is to evaluate and compare two front body structure designs of a new car program using three dimensional lumped spring-mass model so called ‘MADYMO 3D frame model’ in the view of frontal crash with concept drawing only. A MADYMO 3D frame model, composed of a number of bodies and joints, was built for a current vehicle model and correlated with full car crash analysis results from explicit finite element analysis for FMVSS 208 and AMS (Auto motor und sports) crash conditions. Then the same method was applied to a new car structure. The new 3D frame models of two front structure design concepts were built and the result was compared for two crash conditions. Two models were required to reduce footwell intrusion to meet the design target. Several design modifications were tried to reduce footwell intrusion for both models.

This paper includes madymo simulations and sled tests for airbag depowering. A compact vehicle's driver and passenger airbags, developed for previous FMVSS 208 regulation, were depowered 20% and 30%. Sled tests and madymo simulations were performed with the sine sled pulse for baseline and depowered airbags under unbelted condition. The results of simulation were compared with those of sled tests which were conducted according to the procedure of amended regulation. In addition, so-called “ridedown energy” management technique was introduced to improve the understanding of physical differences between sine sled pulse and vehicle barrier pulse. By comparing the sine pulse with barrier pulse of a compact vehicle and a mid sized vehicle, it was found that the sine pulse is a typical body pulse of a large sized vehicle and a compact vehicle pulse normally has shorter vehicle rebound time and higher deceleration peak than sine pulse because of small energy absorbing spaces in engine room.