Variation of Stress at the Impact End of Body in Elastic-Plastic Impact

Abstract

In the present study, a new method for measuring the time-variation of stress at the impact end in the elastic-plastic collision of a body against another body was developed and the duration of impact was discussed.
Firstly, the simple method for measuring the duration of impact, called the sensing cylinder method, was proposed. The sensing cylinder was confirmed by calibration tests to be effective for measuring not only the duration of impact but also the impulsive force generated at the impact end of a body.
Secondly, as an application of the measuring method, plastic impact tests were made on pure copper and aluminum specimens with several different lengths. The time-variation of stress at the impact end of the bars colliding with the sensing cylinder and the duration of impact were measured under various impact velocities. The experimental results were compared with the theoretical ones based on the strain-rate dependent theory of plastic wave propagation. Close agreement between the observed and the calculated values was obtained.