A new yield surface distortion model based on Baltov and Sawczuk’s model

Abstract

In the present study, a new distortion yield surface model is proposed to represent compatible results with experimental observations. The proposed yield surface model is determined numerically during tension–torsion loadings by considering a kinematic hardening model and monotonic loading paths. The experimental results of yield surface determination (Khan et al. in Int J Plast 26:1432–1441, 2010; Naghdi et al. in ASME J. Appl Mech 25:201–209, 1957) represent the nosed and flattened regions in the loading and reverse loading directions, respectively. But, the Baltov and Sawczuk’s yield surface model can only predict nosed or flattened shape in both loading and reversed loading directions, depending on the sign of their model constant. Thus, the elliptic Baltov and Sawczuk’s yield surface is modified by changing the sign of this parameter continuously from loading to reverse loading direction. Relations and convexity of the new model are obtained and discussed. The new model is able to predict properly the shape of the yield surface. The experimental results are in a satisfactory agreement with the new yield surface distortion model predictions.