The Impact End Stress of a Bar Subjected to Longitudinal Compression Impact

Abstract

In the present paper the elastic-plastic stress at the impact end of a cylindrical specimen subjected to longitudinal compression impact with a stress bar which remains elastic during the test is investigated experimentally and theoretically. The measured elastic response of the stress bar showed explicitly an elevation of dynamic stress and its relaxation at the impact end of the specimen. The impact end stress of the specimen was analyzed by using the strain-rate dependent theory for plastic wave propagation, taking into account a rise time of impact and impact conditions. An extreme elevation of the dynamic stress was predicted in the case of a step impact, but it went down rapidly with an increase in the rise time of an impact velocity. Taking the stress as an incident stress to the stress bar, the elastic response of the stress bar based on the Love theory for elastic waves almost agreed quantitatively with the experimental results as well as qualitatively.