Damage Criteria Based on Plastic Strain Energy Intensity Under Complicated Stress State

摘要

In this study, total strain theory and isotropic hardening model based on Mises yield condition are used to derive the expression for plastic strain energy density under complicated stress state. The normal and shear stress distributions of a solid cylindrical bar under a combination of tensile and torsional stresses as well as the equation and integral formula for plastic strain energy density are presented. The plastic strain energy density of critical point and the plastic strain energy intensity on the fracture plane of different materials under several typical stress states are obtained by measuring the fracture data of different materials. With the plastic strain energy intensity as the failure parameter, uniaxial tensile experiments were conducted to measure the final plastic strain energy intensity of the failure section. The plastic strain energy intensity failure criteria of the material under complex stress state are established. Combined tension-torsion tests were conducted on two types of materials, LC9 and LY12, to verify the validity and applicability of the criteria.