A Constitutive Model for Cyclic Loading and Relaxation

Abstract

A new model is proposed which incorporates inelastic flow during cyclic loading and relaxation processes. The model is an extension of Hart’s constitutive model for inelastic flow and is based on the non-steady state condition for the frictional glide process. A new state variable is introduced here as a microhardness parameter which represents the strength or the average lifetime of the mobile dislocations relative to the frictional glide viscous drag process. The evolution of the microhardness parameter is very similar to that proposed for the hardness parameter except that the recovery plays a major role. The results show that the model can predict the transient behavior for both cyclic loading and the reloading phenomena during inelastic deformation and load relaxation.