High cycle fatigue limit prediction of foreign object damaged aerofoil samples by the theory of critical distance

Abstract

The fatigue limit at 3 × 107 cycles predicted by the theory of critical distance (TCD) on Ti–6Al–4V aerofoil samples subjected to foreign object damage (FOD) was studied. First-order bending vibration fatigue experiments were carried out with 18 FOD samples after FOD tests. First-order bending vibration mode analysis of each notched sample with various semi-elliptical notch dimensions were carried out by finite element method and the critical distance is deduced by test results and numerical simulation. FOD and HCF tests were carried out on another 9 aerofoil samples, and fatigue limit predictions were carried out using the Peterson formula and the TCD model. The results showed that the TCD model has higher prediction accuracy.