The Subsequent Yield Surfaces after Proportional Preloading of the Tresca-type Material

Abstract

The subsequent yield surfaces after proportional preloading are experimentally investigated for the materials whose stress-strain curves in the proportional loading are represented by the effective stress-strain relation of Tresca-type. The yield surfaces are obtained by subjecting thin-walled tubular specimens of aluminum alloy to combined axial load and internal pressure. These results are compared with those of combined axial load and torsion. For the Tresca-type materials, the shapes of the yield surfaces represented in the π-plane and in the deviatoric stress plane are found to depend on the direction of the prestress. A new stress plane modified from the deviatoric stress plane is proposed, in which the yield surfaces are given uniquely as a function of the length of the prestrain path.