The role of macroscopic plastic deformation in fretting fatigue life predictions

Fretting damage resulting from contacts under cyclic tangential loading is modeled using the finite element method. Plane strain line contact between a rigid circular cylinder and a semi-infinite elastic—plastic half space is analyzed to predict cyclic strain response. The boundary between active plasticity and elastic shakedown is illustrated as a function of tolerable strain ranges and the amount of strain hardening present. Purely elastic and elastic—plastic analyses are contrasted via cyclic total strain ranges and fatigue life predictions based on a uniaxial strain life model. The results indicate that plasticity acts to concentrate regions of intense cyclic straining at the surface, near the edges of contact. It is shown that the presence of plastic straining, despite its small amplitude, can significantly alter lifetime predictions from those generated from purely elastic analyses.