Configurational forces and J-integrals in cyclic metal plasticity

Abstract

The configurational force concept is known to describe adequately the crack driving force in linear fracture mechanics. It is unclear however, if and how the crack driving force can be defined in the case of elastic-plastic material properties. In metal plasticity, many materials exhibit hardening effects when sufficiently large loads are applied. Von Mises yield function with isotropic and kinematic hardening is a common assumption in many models. Kinematic and isotropic hardening turn out to be very important whenever cyclic loading histories are applied. This holds equally regardless of whether the induced deformations are homogeneous or non-homogeneous. The aim of the present paper is to discuss the effect of non-linear isotropic and kinematic hardening on the response of the configurational forces and to provide suitable concepts for the thermodynamic description of elastic-plastic fracture problems. Further, the applicability of the shown concepts is discussed.