A peridynamic frictional contact model for contact fatigue crack initiation and propagation

Cyclic contact between components can cause cracks in the contact area. Peridynamics can overcome the difficulty of solving cracks and other discontinuities in classical continuum mechanics. A new peridynamic sliding frictional contact model is proposed and verified by a two-dimensional point contact sliding simulation. Then, a two-dimensional plane strain elastoplastic peridynamic model of a single micro-contact asperity is established, and the fatigue crack initiation and propagation in the micro-contact area during fretting wear is analyzed. The results show that in fretting wear, crack initiation originates from the area of maximum shear stress below the surface. The subsurface crack initially propagates in the direction parallel to the surface, and then gradually propagates to the surface. Finally, the crack grows to the free surface and forms wear debris. The contact pressure and the coefficient of friction in the contact surface can affect the crack initiation depth and crack propagation path, thereby affecting the size of wear debris. The crack propagation path is not sensitive to the change of the coefficient of friction of the crack surface. This study helps to understand the mechanism of fretting wear and provides a reference for predicting fretting wear.