Numerical modeling of stress state-dependent anisotropic fracture behavior for WE43 alloy

Accurate prediction for fracture behavior plays an important role in metal forming process. The study aims to uncover and model the effect of anisotropy and stress state on the fracture behavior of WE43 alloy. The mechanical experiments along 0°, 45°, and 90° between the loading direction and rolling direction (RD, DD and TD) were carried out under tension, compression and shear stress states. It shows that the initial yield stress is with weak anisotropy and negligible tension-compression asymmetry, while the hardening behavior shows some anisotropy related to strain. The plastic ability along DD is preferred to that along RD and TD under uniaxial loading. The fracture behavior belongs to the ductile fracture with tension and shear mechanisms, which is dependent on the stress state and loading direction. An analytical anisotropic Drucker yield function is proposed to capture the evolving yield behavior with non-proportionality. The fracture-related variables from plane strain compression to plane strain tension along different loading directions are obtained with acceptable prediction accuracy by adopting the hybrid experimental-numerical method. A Drucker-DF2016 anisotropic fracture criterion is established based on the linear transformation tensor to characterize the coupling effect of anisotropy and stress state on the fracture behavior of WE43 alloy with an error of 0.054, which is smaller than the error (0.2908) of the Yld91-DF2014 anisotropic fracture criterion. The fracture location in numerical simulation is basically consistent with the fracture location in the experiment. This research provides an analytical yield function and anisotropic fracture model to be applied into the numerical modeling of the yield and fracture behaviors of metals.