The mixed-mode propagation of fatigue crack in CTS specimen
CTS试件中复合型疲劳裂纹扩展

In this paper, the mixed-mode fatigue tests are carried out with the CTS specimen (Compact-Tension-Shear) and the mixed-mode loading device developed by Richard 1]. Three loading angles and two materials are selected in the experiments. The effect of loading angle on the crack propagation is analyzed numerically and experimentally. According to the experimental results, the fatigue crack growth rate is related to the loading angle. For the same initial equivalent stress intensity factor (combination of the stress intensity factor in mode I and in mode II), the crack grows slowest under pure mode I loading. The photos of crack bifurcation and the results of the crack growth rate in different specimens under different mixed-mode loadings are presented. Furthermore, a numerical model of fatigue crack propagation is proposed on the basis of the experimental results to evaluate the influences of loading mode on the crack growth rate. The validation of the model is performed on the steel specimens under mixed mode loading. The numerical evaluations are in good agreement with the experimental results.