き裂開口変位分布に基づく疲労き裂伝ぱ挙動の考察

切欠き付近の残留応力分布に注目して

抄録

A method was proposed which evaluates crack opening stress distribution and stress intensity factor from the crack opening displacement distribution near a circular-hole. The fatigue crack and the low-temperature annealed crack emanating from the hole were prepared and the crack opening displacements were measured along their faces. The difference in the crcak opening stress distribution between the fatigue and the annealed cracks was used to estimate the residual stress distribution along the fatigue crack. They showed the compressive residual stresses near the hole and the crack tip, but the tensile ones between them, which were caused by cyclic deformation near the hole and subsequently redistributed due to fatigue crack propagation. The stress intensity factors estimated from the fatigue crack opening displacements were smaller than those calculated from the applied stress and were closely related to the change in fatigue crack propagation rate.