A Study on the Equivalent Stress and the Equivalent Plastic Strain Rate : Theory of Anisotropic Plasticity Based on the Maximum Shear Stress Hypothesis

抄録

A conception of the equivalent stress and the equivalent strain rate can be used for comparison of the yield surfaces or the stress-strain diagrams of the materials deformed plastically under combined stresses. There is a close relationship between formulating the equivalent strain rate and selecting the type of the equivalent stress. In this paper, when the principal axes of anisotropy coincide with those of stresses, a new conception of the equivalent stress and the equivalent strain rate is suggested for the theory of anisotropic plasticity based on the maximum shear stress hypothesis. Then it is found that lines connecting the tops of strain rate vectors on the sides and corners of the yield surface becomes straight lines respectively, that is, the tops of these strain rate vectors from a polygon when the equivalent strain rate or the change of the amount of deformation is constant. Theoretical results obtained here are concise and this will make it easy to analyze the problems of plastic anisotropy.