Rate-dependent Behavior in Cyclic Plasticity : Description Based on the Random Barriers Theory

Abstract

A descriptive model for rate-dependent behavior in cyclic plasticity, based on the random barriers theory, was presented by considering the velocity of a moving dislocation which was one of the movable dislocations and named a"free dislocation"in this paper. Each of the stress- and strain-rate sensitivities on the stress-rate relation in each half cycle could be fairly well estimated on the basis of an equilibrium equation derived in this study as a function of the stress-rate and the strain-rate at any stress level. Moreover, several types of transient behaviors caused by a sudden change in the stress- or strain-rate might be uniformly expressed by each analysis of the processes in which a deficient or excess quantity of the free dislocations in this period came close to the moderate quantity decided by the stress and stress-rate.