Experimental and numerical study on the fretting wear-fatigue interaction evolution in press-fitted axles

Fretting fatigue in press-fitted axles is closely related to fretting wear. However, most studies have been limited to the effect of fretting wear on crack initiation, neglecting the interaction influence between fretting wear, crack initiation, and propagation. In this study, interrupted fretting fatigue tests of press-fitted axles were conducted. The evolution of the surface damage and fretting cracks with the number of test cycles was observed and measured. Then, based on numerical simulations, the fretting wear-fatigue interaction evolution was investigated. The results indicated that the stress redistribution resulting from fretting wear led to fretting crack initiation within the fretted wear scar. Due to fretting wear, the compressive stress within the press-fitted region was released and the stress field surrounding the crack tip was enhanced, promoting the propagation of fretting cracks, especially those close to the contact surface. Fretting crack propagation resulted in the loss of stiffness of the axle and locally prevented the transmission of bulk stress to the inner side of the contact surface. The shear traction and slip range were redistributed, alleviating the fretting wear near the wear boundary and increasing the surface damage within the region close to the right-hand side of the crack.