T-stress based short crack growth model for fretting fatigue

Abstract

The aim of this work is to model short crack growth under fretting fatigue loading conditions by considering a criterion based on linear elastic fracture mechanics quantities, which also accounts for the first non-singular terms of the asymptotic expansion, namely the T-stresses. The Modes I and II Stress Intensity Factors and the T-stresses were computed by the finite element method under plane strain hypothesis. To assess the model fretting fatigue tests were carried out using two cylindrical fretting pads, which were loaded against a flat dogbone tensile test piece, both made of a Ti–6Al–4V titanium alloy. The model was capable to correctly estimate short crack arrest and to find the threshold fretting conditions separating failure from infinite life (here defined by tests which reached one million cycles). An optimization technique was implemented to the numerical model so that it could also estimate crack path.