Axisymmetric Bifurcations of Metals with Tangential-Subloading Surface Model

Abstract

This article discusses about localized bifurcation corresponding to shear band formation and diffuse bifurcation modes of deformation, such as necking and bulging, for a cylindrical metallic specimen subjected to tensile or compressive loading under axisymmetric deformations. Further, conditions for the shear band formation, the diffuse bifurcations, and the long and short wavelength bifurcation are discussed in relation to material properties and their state of stress. We employ the tangential-subloading surface model, in which tangential-inelastic strain rate term makes the inception of bifurcation modes easier in not only normal-yield, but also subyield states. Furthermore, their formation is severely affected by the normal-yield ratio describing the approach of magnitude of stress to that of the normal-yield state.