Damage evolution and fracture of aluminum alloy based on a modified Lemaitre model

Abstract

Ensuring that metal materials do not fail during the forming process is a concern; forming is a complex process with development of a large amount of macroscopic and mesoscopic damage inside the metal. In this study, the damage evolution of 5052 aluminum alloy during the plastic forming process was studied using a modified Lemaitre damage model. First, a combination of theoretical derivation, experimental analysis, and fracture scanning was used to study the material damage evolution law at different strain rates. Subsequently, a more accurate nonlinear relationship between plastic strain and damage value was proposed, and an assumption regarding the Lemaitre damage model was revised. A VUMAT user material subroutine based on the Lemaitre damage model was developed; the reliability of the modified Lemaitre damage model was verified by numerically simulating the tensile process of 5052 aluminum alloy at different strain rates. The relative error between the fracture failure location of the specimen obtained from the numerical simulation of the modified Lemaitre model and that in the experiment was 3%.