Effect of fretting wear on crack initiation for cylinder-plate and punch-plane tests

Numerous studies highlighted the influence of the fretting sliding conditions on fretting damage. Gross slip may lead to material removal while partial slip conditions favor crack initiation and propagation. The aim of this work is to develop a robust computational framework for fretting simulation in both regimes including both wear and fatigue-crack initiation. This framework involves the resolution of the contact problem, damage accumulation, update of the geometry and automatic remeshing to capture the material removal. A detailed description of the employed wear and damage models is presented; the competition of the two corresponding mechanisms determine weather the damaged zones are worn out or weather a fatigue cracks are initiated. The wear model is based on a non-local wear criterion making a link between friction energy density and the local wear depth, which enables to update the surface profile for the following calculation step. A Smith-Watson-Topper (SWT) parameter combined with a linear cumulative law allows to predict the crack-nucleation risk. The selected material under study is a classical titanium alloy, Ti-6Al-4 V. A series of numerical simulations is carried out to study the influence of surface wear on fretting damage distribution under different slip regimes for two contact geometries: a cylinder-on-plane and a punch-on-plane. Our numerical results enable us to distinguish various damage mechanisms and are in a very good agreement with experimental data taken from the literature.