1986 年 4 巻 4 号 p. 715-722
Fatigue crack propagation under repeated variable amplitude loading in welding tensile residual stress fields was studied experimentally in low propagation rate region (low dK region). Material used was steel of 800 MPa in tensile strength. Specimens were center-cracked-plates with a longitudinal bead on center of specimen.
Major results obtained are summarized as follows.
Fatigue crack propagation rate under repeated variable amplitude loading was estimated from linear accumulation rule for relation between crack propagation rate and dK under constant amplitude loading. Threshold value of dK in the relation, however, had to be changed to the value in appearance.