Mixed mode fatigue crack initiation and growth in a CT specimen repaired by stop hole technique

The crack growth retardation and the location of fatigue crack initiation from stop-hole edge under different mode-mixities are examined in this paper by means of a developed fatigue code. Different loading conditions have been generated by using a mixed-mode CT specimen made of Al6061-T651. The numerical results reveal that in the presence of stop holes the reduction in the stress concentration becomes larger for mode-II loading conditions. A comparison between the reported experimental results and the obtained computational results shows that the fatigue life extension of repaired specimens can be well predicted by the numerical model developed in this study