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The present analysis concerns collapse behavior of vehicles under the quasi-static loading condition as analysis for the initial stage of conceptual design. Collapse analysis of a vehicle model with the space-framed structure is carried out using finite element limit analysis. To improve collapse response and strengthen weak parts, the dimension of the section and the position of the frame are locally changed as design parameters. The results demonstrates that the present analysis can easily predict weak parts of the structure and the change of design parameters enhances the load-carrying capacity of vehicle structures and reduces the deflection toward the passenger compartment.

In order to evaluate the crash-worthiness of a car, the dynamic response of the car body has to be correctly obtained at each level of car velocity. For the dynamic analysis, the dynamic properties of auto-body materials need to be identified for various strain rates. One of the typical high strain rate tensile tests is a split Hopkinson bar test. The present experiment has been carried out with a new split Hopkinson bar apparatus specially designed for the dynamic tensile test of sheet metals. The experiment provides stress-strain curves for various strain rates ranged from 2500 to 5000/sec. The experimental results from the both quasi-static and dynamic test are used to construct the Johnson-Cook equation as a constitutive relation, which can be applied to simulate the dynamic behavior of auto-body structures.