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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.

This paper presents an analytic method to estimate the proper space and stiffness of the vehicle's pillar trim to meet FMVSS 201 head injury criteria. A practical guideline curve, which is used in determining the adequate space and stiffness of pillar trim, is derived assuming haversine curve for the head impact pulse. Rib structure of pillar trim, which has a required stiffness, is designed using further simplification that models the BIW and the trim as equivalent springs. The required stiffness of the trim was achieved by adding a rib structure to it, and the shape of the rib structure was obtained using finite element analysis. Finite element analysis and experiment were conducted to validate the design of the trim, and the results were very close to the required stiffness.

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.

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 describes an analytical method to find optimal side structure of convertible vehicle for occupant protection using full vehicle finite element model compared with typical notch-back style vehicle. The strategy of occupant protection for convertible vehicle is quite different from that of notch-back sedan in the view point of vehicle structure due to the limitations in building concept of side structures. In this study, the strategy leading to reliable results in the convertible type vehicle will be discussed. This analysis work shows a good preliminary result for predicting vehicle side structure behavior and occupant injury in early stage of car developing program.

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.