抄録
The purpose of this paper was to investigate quantitatively the effect of tensile residual stress on fatigue crack propagation based on the experimental facts and the linear fracture mechanics. In the experiment, the X-ray oscillating stress measurement method was applied to examine the residual stress distribution around a precrack in the plate specimens which were made so as to have longitudinal residual stress due to water cooling from the temperature below 873K. By using these specimens, it was confirmed that the acceleration of the fatigue crack propagation from the precrack in tensile residual stress field was induced by the crack opening due to the tensile residual stress. On the other hand, it was found that the initial stress intensity factor of precrack in tensile residual stress field could be calculated by substituting the measured value of tensile residual stress for the crack opening stress on the ideal crack surface in a linear fracture mechanics model. The effective stress intensity factor range calculated from the initial stress intensity factor of precrack was useful for understanding of the fatigue crack propagation from the precrack in tensile residual stress field.
