Plastic flow potential for cone region of MRS-Lade model

The original formulation of the MRS-Lade model, with nonassociated flow rul e on the meridian plane in the cone region, has a corner. In order to reduc e the computational effort of corner solution algorithms, a modified plasti c how potential for the cone part is found in the literature. This modifica tion may have a nonadmissible flip over of the flow vector in the cone-cap intersection if the plastic flow potential is not correctly defined. Here a corrected plastic flow potential for the cone region is defined to obtain a continuous transition of the flow vector.