THE MECHANICAL PROPERTIES OF COPPER AT HIGH STRAIN RATES Volume II ANALYTICAL AND EXPERIMENTAL PLASTIC STRAIN PROFILES IN HIGH VELOCITY IMPACT

摘要

Cold-drawn copper rods were end-impacted with projectiles having lengths of 1 to 5 inches and initial velocities of 500 to 1240 in./ace, send the resulting plastic strain profiles were measured. Also the strain profiles were calculated using a numerical method based on the method of characteristics and on material properties which are rate sensitive. The reliability of the concepts employed in these calculations was indicated by the good agreement between the measured and calculated strain profiles. Strain rate exponent, defined as the slope of the curve of log stress versus log plastic strain rate, was found by these calcula-tions to increase with increasing strain rate, reaching a value of about 0.04 at a plastic strain rate of 400 sec-1.