High-Density Pulse Current-Induced Unsteady Stress-Strain State in a Long Rod

Abstract

The results of experimental investigations and numerical calculations of the unsteady stress-strain state in a thin steel rod (wire length) prestressed statically below the yield strength upon the passage of a high-density current pulse are presented. The current pulse gives rise to oscillations of axial stresses with a period corresponding to the period of natural longitudinal oscillations of the rod. Maximum compression and tensile stresses are determined by current pulse front duration and its amplitude. A high level of the above stresses in the central portion of the rod brings about local losses of longitudinal stability. The results of numerical simulation of the stress-strain state in the rod upon its heating with a current pulse correspond to experimentally observed effects. A current pulse-induced decrease in the level of initial tensile stresses (at constant strains) produced by static loading points to the development of relaxation processes that are associated not only with heating. To separately evaluate the effects stemming from elastic stress waves in the rod, heating, and immediate current action, further studies would be required.