Three-dimensional mode-I/III fatigue crack propagation: Computational modeling and experiments

Three dimensional mixed mode-I/III fatigue crack growth simulations and experiments are performed on Al7075-T651 aluminum under different mode mixity ratios. The crack growth surfaces obtained from numerical models are compared to experimental results. Good agreement is achieved with experimental results on prediction of crack growth surfaces for up to upper intermediate levels of mixed mode loadings. Based on the computed mixed mode stress intensity factors from the numerical analyses, fatigue crack propagation lives are also predicted using different criteria. The results show that all of the mixed mode criteria evaluated in this study underestimate fatigue crack growth lives.