The mixed-mode investigation of the fatigue crack in CTS metallic specimen

The experiments of a fatigue crack under mixed-mode loading are performed with CTS (Compact-Tension-Shear) specimens associated to a mixed mode loading device. The effect of loading angle on crack growth rate and on crack bifurcation angle is analyzed. Also, the welded specimens are introduced in the experiments in order to investigate the influence of the filled weld. In the fatigue tests, three loading angles, two loading levels and two materials are selected in the experiments. Furthermore, on the basis of the experimental data, a mixed-mode crack growth model is proposed in order to evaluate numerically a fatigue crack growth rate, in which the effects of the loading mode and of the residual stresses due to weld are considered. The validation of the model is carried out on CTS specimens under mixed mode loading.