RESEARCH ON TRIPLE-SHEAR YIELD CRITERION FOR MATERIALS

A triple-shear yield criterion is proposed through analyzing the Tresca yield criterion and the twin-shear yield criterion by taking account of the combined actions of all three principal shear stresses acting on the dodecahedron element. The loci on the π plane and (σ₁,σ₂)plane, the Mohr circles on the (σ,τ)plane, the effective curves with the intermediates principal stress, and the slip directions are analyzed for it. Similar to the unified yield criterion, the proposed criterion can represent a series of yield criteria in which the Tresca yield criterion and the von Mises yield criterion are only its special cases. The loci and the effective curves of the criterion are of nonlinear types that could give a better description to the yield characteristics of materials. On the other hand, this criterion overcomes the disadvantages of the twin-shear yield criterion with double slip planes and sudden changes of slip directions when materials are in some special stress states.