Integration of plasticity equations for singular yield functions

Abstract An algorithm is described which properly handles integration of stress-strain laws at singular points in a yield surface. Koiter's requirements for such points are incorporated exactly within the proposed algorithm. The conditions for which the stress, after correction for plastic flow, exactly satisfies the yield function are discussed. The algorithm is elaborated for the Mohr-Coulomb and Tresca yield criteria and an explicit expression is provided to decide whether the current regime is a corner of the yield surface or not.

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