1984 年 33 巻 368 号 p. 578-583
The fatigue life prediction of butt welded joints was investigated by paying attention to fatigue cracks originating at the weld toes. The experimental results indicated that the fatigue crack initiation life depended on the weld toe configuration. The effect of stress concentration at the weld toes was estimated by a local strain approach with due consideration for the scatter of the stress concentration factor.
The shallow fatigue cracks, 0.5-1.0mm, initially grew fast under the influence of stress concentration at the weld toes. The propagation of cracks more than 0.5-1.0mm was not affected by the weld toes. Since in this experiment, the fatigue crack initiation was defined as the state in which the crack depth became 0.5mm, this experimental result showed that the fatigue crack propagation life hardly depended on the weld toe configuration. From an engineering point of view, the fatigue crack propagation life can be estimated conveniently by the linear fracture mechanics analysis based on the assumption of the initial crack depth of 0.5-1.0mm at the weld toes, as described above.