摘要：Based on the ABAQUS/Standard platform and the characteristics of loading and unloading for autofrettage, the User-defined Material Mechanical Behavior (UMAT) subroutine of hybrid hardening constitutive relationship was developed. In this implicit algorithm, parameter of back stress, loading parameters and isotropic hardening coefficient were introduced, algorithm for stress compensation updating and consistent stiffness matrix updating were used. After the reliability verification, this UMAT was used for autofrettage residual stress analysis of notch ring specimen’s model. Experimental and Comparison results showed that analysis results of residual stress field based on UMAT were accurate. The effect of isotropic hardening coefficient on maximum residual equivalent stress, maximum compressive residual stress and depth of residual compressive stress zone were examined. The results showed that under the same autofrettage process condition, the residual compressive stress would increases with isotropic hardening coefficient but the depth of residual compressive stress zone decreases with the increase of isotropic hardening coefficient. The findings have significant influence on the improvement of autofrettage technology.
