抄録
Fatigue crack propagation test were performed on single edge-notched pre-strained 7075-T6 aluminum alloy specimens. The similarity between the effect of pre-strain and that of stress ratio on fatigue crack propagation rate was confirmed by taking the acccumulated plastic strain rate, which involves not only the accumulated plastic strain in the monotonic plastic zone but also the plastic pre-strain. An analytical expression was proposed to explain the effect of pre-strain (i. e., the effect of cold work) quantitatively together with the effect of stress ratio. The applicability of this expression was evaluated by examining the effects of cold work and stress ratio on fatigue crack propagation rate of 7075-T6 aluminum alloy and various alloys determined previously.
