Abstract
Discontinuity at the vertex of the Sekiguchi-Ohta model causes numerical troubles when associated flow rule is applied because the singularity encountered in the derivatives of yield function. Based on Koiter's associated flow rule, the numerical implementation to accommodate the vertex singularity had been generalized. The set of applied strains had been formulated and defined as the domain of metastability. This study is focused on validity of the domain of metastability by a regularized method. Infinitesimal vicinity adjacent to the vertex is considered to regularize all of plastic flow in outwards normal direction to the yield surface. It was confirmed that the metastable domain of the Sekiguchi-Ohta model is bounded by an elliptical cone in principal strain space.
