Finite element analysis of fretting fatigue under out of phase loading conditions

Fretting fatigue is a complex phenomenon involving various factors, such as slip amplitude, coefficient of friction, shear load and loading phase difference. In this study, three numerical models are used to model the effect of both in phase and out of phase loading on contact stresses and damage initiation locations. Three phase difference angles are considered, i.e. 0, 90 and 180, for this purpose. It is observed that phase difference affects the shear traction and tensile stress profiles at the contact interface, whereas no significant effect is observed on convergence efficiency. It is also shown that, due to increase of stick zone width, the convergence is slower during the unloading step than during the loading step. SWT parameter and Ruiz parameter are adopted as two crack initiation criteria in order to investigate their performance in case of out of phase loading. The critical locations predicted by both parameters have shown good agreement with experimental results from literature. In addition, it is observed that phase difference significantly affects the damage initiation location.