A Constitutive Equation in Cyclic Plasticity Based on the Random Barriers Theory

Abstract

A constitutive equation in rate-independent cyclic plasticity was presented with a new plastic potential function dependent on the field of resisting force against the movement of dislocations. By extending the model proposed in the previous paper for a uniaxial case, it was assumed in this study that each process of the cyclic deformation under multiaxial loading should be attached to the processes of either to or formation, and a simple rule of conversion from one process to the other was postulated by considering the stress history. Moreover, an effect of anisotropy, produced by cyclic deformation, was reflected in the internal structure variable which was one of three internal state variables describing the force field. The propriety of this equation without any yield surface has been examined with some experiments obtained from the axial-and torsional-load cycling tests with tubular specimens of a carbon steel.