Identification of the fatigue stress intensity factor threshold for different load ratios R: From fretting fatigue to C(T) fatigue experiments

The aim of the study is to demonstrate the similar behaviour of crack arrest condition in mode I for partial slip simple fretting, prestressed fretting loadings, and conventional fatigue crack growth experiments. The stress intensity factor range ΔKth threshold of long crack is estimated based on crack arrest condition for partial slip fretting and prestressed fretting loadings, coupling experimental and FEM computations. The experimental work is performed on a cylinder (Ti–6Al–4V)/flat (Al-7050-T7451) interface. Fretting and prestressed fretting tests are performed to obtain the crack length at a crack arrest condition. Conventional fatigue crack growth experiments are performed on C(T) samples using a wide range of R to validate the fretting approach. The results and analysis show that using a reverse FEM analysis of crack arrest applied to fretting experiments, the fatigue long crack threshold region is determined for stress ratios between −2 and 1.