Variation of Stress Distribution in Metal Fracture Process under Compressive, Torsional, and Tensile Loading

In order to accurately fit the failure criteria in JC failure model, BW failure model, and MMC failure model, numerical simulations for metal materials Q345B and 921A under various loading conditions of compression, torsion, tension were performed in this work. The variation of stresses, indicated by stress triaxiality and Lode parameter, was investigated during the fracture progress. The results indicated: (1) exclusive of torsional loading, the stress distribution varied in the cracking plane as the crack growth; (2) the average stress triaxiality and Lode parameter are more suitable for describing the stress status; (3) for specimens having the same size, the value of average stress triaxiality was dependent on metal properties. This work would provide useful knowledge for obtaining the failure criterion from material failure experiments.