자동차용 강판의 동적 인장특성 평가

Abstract

The dynamic behavior of automotive steel sheets is dependent on the material strain rates. Therefore, the dynamic material properties of steel sheets are indispensable for the accurate crashworthiness analysis of auto-bodies. This paper evaluates the dynamic tensile characteristics of automotive steel sheets; Mild Steel, HS440MPa, HS590MPa and HS980MPa along the rolling direction and transverse direction. Dynamic tensile tests were carried out at the strain rate of 0.1/s to 200/s using a high speed tensile test machine(INSTRON VHS 65/85-25). Static tensile tests were carried out at the strain rate of 0.003/s using the static tensile test machine(ZWICK Z250). The tensile tests acquired stress-strain relations and strain rate sensitivities of each material. The test results showed that the flow stresses increased as the strain rates increased and the effect of strain rate hardening decreased as the tensile strengths of materials increased.