T-stress effects on fatigue crack growth - Theory and experiment

The effects of specimen geometry on the fatigue crack growth rate and the number of elapsed cycles have been investigated experimentally and theoretically for Al 7075-T6 using four different cracked specimens with positive and negative T-stresses. All the specimens have been tested under high cycle fatigue loading. An energy-based method, namely the generalized strain energy density (GSED) criterion has been proposed to estimate the fatigue crack growth rate and the number of elapsed cycles by considering the T-stress effects. It is shown that the proposed criterion can provide significantly improved predictions for the fatigue crack growth behavior of the pre-cracked specimens.