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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.

The offset crash performance of a vehicle is getting important in reducing occupant injuries in a high-speed frontal collision on real road. To enhance the performance, we have to keep the passenger compartment space and distribute a half side load to a whole vehicle body structure. In this point of view, a cradle type front wheel carrier system can be very effective. But it poses a little difficulty in using various engine and transmission combinations. But a short wheel carrier system provides a flexible engine room package even though it has a conceptual weakness to offset crash protection. The wheel carrier connecting bar supporting between a short wheel carrier and a radiator supporting cross member is suggested. Two offset crash test modes (Euro NCAP, IIHS) are simulated for developing the wheel carrier connecting bar and modifying the vehicle body structure.

An investigation has been performed to predict full vehicle frontal crash behaviors in collapse zone of the front side rail through the front sub-structure vehicle impact test. Attaching the front structure of a vehicle to the rear crash (FMVSS301) moving barrier makes the front sub-structure vehicle. The test condition is set-up to represent full vehicle crash mode in the collapse zone of the front side rail, a sub-structure FE model is built from full vehicle FE model. Mass and initial velocity of the model are changed so that the model has the same kinetic energy on the US-NCAP frontal crash condition. A preferable model in point of a test set-up is suggested and the analysis result is compared with the other results. The model has 1950Kg of the mass and 20Kph of the impact velocity. Even though the model has 17% of the US-NCAP kinetic energy the result of the sub-structure model look similar to that of full vehicle FE analysis in point of deformation and transmitted section force.