Effect of Mean Stress on Fatigue Crack Initiation and Propagation

抄録

This investigation was carried out to estimate the effect of mean stress on behaviour of the crack which was initiated at the edge of a hole and propagated on the surface of specimen with a transverse-circular hole under the fluctuating twisting moment. It was concluded that the life to the crack initiation did not depend on the mean stress, but only on the alternating stress and the relation between the rate of crack propagation and the stress could be expressed by : logΔl/ΔN=Aσ_a+Bσ_m-C, where A, B, and C are positive constants, σ_a, the alternating stress, σ_m, the mean stress and that the effect of the alternating stress on the rate of crack propagation was larger than that of the mean stress.