Estimating Life Scatter in Fretting Fatigue Crack Initiation

A new approach was developed to estimate the crack initiation life of a fretting contact while accounting for the variability in the fatigue response. This was accomplished using a modified application of the Smith-Watson-Topper (SWT) fatigue criterion. A combined finite–discrete element model of a cylinder-on-flat configuration incorporating material randomness and disorder via a Voronoi tessellation was developed. The SWT equation was used with this model to predict the crack initiation lives for multiple material domains. The predicted crack initiation lives displayed a large degree of scatter and were less conservative than previous deterministic implementations of the SWT parameter. The scatter in the predicted initiation lives was quantified using Weibull statistics.