자동차 차체의 충돌해석을 위한 박판의 동적거동

Abstract

Identification of dynamic response of the auto-body is important to evaluate the crash worthiness of a car. A split Hopkinson bar could be used for obtaining high strain rate material properties of sheet metals. In this paper, experiments have been carried out with a new split Hopkinson bar apparatus specially designed for the dynamic tensile test of sheet metals. The experimental results are used to construct a dynamic constitutive relation of sheet metals as the Johnson-Cook model. The conventional Johnson-Cook model has a linear term for strain hardening of the semi-logarithmic scale, which must be modified to a higher-order term to satisfy the experimental results. The constructed constitutive relations are applied to simulating the crashworthiness of a simplified car body.