Crack Growth Propagation Prediction in Non-Proportional Mixed-Mode Missions

The present paper focuses on the prediction of cyclic crack propagation due to missions with varying mixed-mode loading conditions. Overall, 18 different loading conditions are simulated and the numerical results are compared with the corresponding experimental results. The deflection angle prediction in correspondence of the complete mission is based on the Maximum Tensile Stress (MTS) criterion, coupled with the dominant step approach. The entire numerical simulation procedure relies on the algorithms implemented in the commercial FRacture ANalysis Code 3D, FRANC3D, and ABAQUS software. Numerical and experimental fracture surfaces, in correspondence of tension-torsion tests with and without phase shift, are compared by using an MTU in house tool, CT3D_Validator, with the aim to assess the accuracy of the numerical simulation procedure in determining the crack propagation direction.