Dynamic Compressive Test for Determining Stress-Strain Relation of Material

Abstract

An experimental method of determining the dynamic stress-strain relation of materials and the results of tests on specimens of annealed copper are reported in this paper. 1) Remarkable stress drops after the dynamic yield stress were observed in the stress-strain curves of copper in a certain range of strain rates. 2) The stress near the impact end of the specimen should be considered as three dimensional. In practice, however, if the ratio of specimen diameter to pulse length is reduced sufficiently, uniaxial stress state should be realized, so that this method can be employed to determine the dynamic characteristic of materials. Furthermore, a constitutive equation of metal was proposed from the standpoint of relaxation phenomenon. But for a more reasonable description of the dynamic plastic behavior of metals it may be necessary to take the strain history into consideration.