Description of cyclic hysteresis behaviour based on one-parameter model

The one-parameter model of Kock and Mecking, which is limited to monotonic loading, is extended to account for cyclic hardening/softening behaviour for the case where flow is governed by the glide motion of dislocations. The present model consists of two simple first-order differential equations, one describing the rate of change of stress with strain within a cycle, and the other describing the rate of change of peak stress with cumulative cycle strain. The coupled effect of these two equations enables the description of cyclic hardening or softening behaviour. Calculated results from the present model are compared with experimental strain-controlled cyclic deformation data of polycrystalline copper. Agreement between the two is very good.