High Speed Tensile Tests of Plastics at the Intermediate Strain Rate

Abstract: In the past, the static load−displacement curve was sufficient to predict the deformation of plastics. As plastics have increasingly been used in more applications such as automotive pasts, the dynamic material properties considering the strain rate and temperature become important. In plastics, the stress is typically very sensitive to the strain rate, but results for dynamic material properties at the intermediate strain rate ranged from 1 /sec to 500 /sec do not have been published sufficiently. This paper introduces a newly developed high speed material testing apparatus for tensile tests at the strain rate up to 500 /sec and dynamic material properties of plastics from experiments. Stress−strain curves were acquired for the polycarbonate and the polypropylene from the dynamic tensile test and utilized to obtain the relationship of the stress and the fracture elongation to the strain rate. Key words: High speed material testing machine(고 속 재료시험기), Intermediate strain rate(중변형 률 속도), Strain sate hardening(변형 률 속 도 경화), Plastics(플라스틱, Load ringing phenome on(하 중 떨 림 현상)