Yield Surfaces of SUS304 After Cyclic Preloading

Abstract

To formulate the constitutive equations for cyclic plasticity, the subsequent yield surfaces should be examined carefully. In this paper, using a 50μm/m offset strain criterion for yielding, the subsequent yield surface has been measured from the experiment for the initially isotropic material of SUS 304. The experiment shows a translation, distortion, expansion and rotation of the subsequent yield surfaces due to the deformation-induced anisotropy resulting from proportional or nonproportional cyclic loading tension-torsion space. These yield surfaces could be represented by the quadratic form of stresses with fourth rank anisotropic coefficient tensor components. These anisotropic coefficient tensor components are found to be related to the strain amplitude of cyclic loading. As a result, the loading function obtained facilitates the derivation of constitutive equations of cyclic plasticity.