Fracture of 1045 steel under complex loading history Yuanli Bai

In the paper, a 3D fracture locus of 1045 steel under proportional loading conditions was calibrated using round, plane strain, and tubular specimens. The fracture locus includes both the stress triaxiality and Lode angle dependence. As an extension to the conventional linear damage evolution assumption, a new form of ductile fracture model considering the loading history effect was proposed, in which two weighting functions were introduced to the damage indicator calculation. One considers the non-linear damage evolution under proportional loading, the other accounts for the effect of change in loading directions. A round of comprehensive fracture tests on 1045 steel was conducted to validate the proposed fracture model. These tests include monotonic loading tests for 3D fracture locus calibration and other tests with complex loading histories, for example two-stage-tension test, compression-tension test and torsion-tension test.