AN ELASTO PLASTIC CONSTITUTIVE EQUATIONS FOR THE STAINLESS STEEL UNDER COMBINED AXIAL AND TORSIONAL LOADS PART I. EXPERIMENTS
拉─扭复合加载下不锈钢的弹塑性本构关系─I．实验

In the present paper, a series of experiments were performed on the plastic deformation of a thin walled tubular specimen of 1Cr18Ni9Ti S.S. along trilinear, circular and elliptical strain paths under combined loads of axial force and torque. The effects of intrinsic geometry of loading path on the magnitude and the direction of stress vector were investigated in plastic strain vectoral space. Experimental results show that the delay,the instantaneous softening and the recovery of hardening of stress response are related tightly to intrinsic geometry of loading path. Lensky's hypothesis of local determinability is not hold in general loading. The deformation history and the coupled effect among strain components have significant influences on the response. The preliminary TEM tests show that the dislocation substructures in the material are dependent on the plastic deformation history.