Duration of Contact at Plastic Impact of Two Bars

Abstract

The present paper deals with a problem on the duration of impact between two bars. The two bars collide with each other longitudinally, one being plastically deformed and the other remaining elastic during the collision. In order to estimate the duration of contact between the two bars impacting each other, the variations of stress at the impact end are examined theoretically and experimentally. The theoretical predictions based on the strain-rate dependent theory for plastic wave propagation show that as the length of a specimen, the impact velocity and the magnitude of the dependence of strain-rate increase, the duration of contact increases regardless of the rising mode of the impact velocity and its rise time. The experimental verification was made by measuring the time variation of elastic-plastic stress at the impact end of a lead specimen in collision with an elastic stress bar made of carbon steel. The theoretical predictions almost agreed with the experimental observations.