Study of anisotropic crack growth behavior for aluminum alloy 7050-T7451

Hill's normalized plastic zone at crack tip under mode-I and mixed-mode loadings were studied in compact-tension-shear specimen. Effects of the parameters of Hill's criterion on the normalized plastic zone were analyzed. Moreover, the shapes of normalized plastic zones for distortional and total strain-energy-density were investigated. To analyze the crack growth behavior by different normalized plastic zones, fatigue crack growth tests of AA7050-T7451 were performed using digital image correlation technique. The initiation angle predicted by anisotropic R-criterion under mixed-mode loading is closest to experimental data.