General Hosford yield functions of orthorhombic materials

Abstract

Although the Hosford yield function is more suitable for describing both the yielding and the plastic deformation of orthorhombic materials than the Hill quadratic yield function, the Hosford yield function suffers from the restriction that the loading has to be coaxial with the orthotropy of the materials. To relax this restriction, herein we present a new general Hosford yield function for the orthorhombic materials. The new general Hosford yield function is suitable to any stress state of the orthorhombic materials. When η = 2, the new general Hosford yield function becomes the Hill quadratic yield function. The new general Hosford yield function is more general than the general Hosford yield function of Huang and Man (Int J Plast 41:97–123, 2013), which covers only weakly-textured sheets of cubic metals. Two examples show that the new general Horsford yield function with suitable η value gives much better fits than those of the Hill quadratic yield function (η = 2).