An expression of elastic-plastic constitutive law incorporating a stress increment dependence. (4th Report; Determination of stress increment dependency parameters at the proportionally prestressed state).

Abstract

In the first report, a new expression of a constitutive law for elastic-plastic material was proposed using two transition parameters which describe the stress increment dependency. These parameters denote the magnitude and the direction of plastic strain increments. In this report, these are determinded by the biaxial loading test of aluminum specimens using testing machine constructed by trial and by the numerical simulation based on the KBW model. The results show that the stress increment dependency is the most considerable at the simple tension and decreases when the stres vector is turned toward the direction of the pure shear.