角回し溶接止端部に存在する表面き裂に対するWES2805 CTOD設計曲線の適用性に関する検討

Abstract

In The Japan Welding Engineering Society standard WES 2805-1997, a fracture mechanics parameter, crack tip opening displacement (CTOD), relative to the flaw located in highly stressed region surrounded by clastic stress field is estimated using the CTOD design curve from the flaw size and the applied local strain considering strain concentration in the components. In this report, finite element analyses using three-dimensional solid elements and tensile tests were performed to evaluate an accuracy of CTOD estimated by the design curve for a continuous circumferential surface crack which was present at the corner boxing toe. It was found that a CTOD estimated by the design curve in WES 2805 had to allow for a great margin of safety. It was possible to estimate a CTOD accurately using te applied local strain calculated from the correction function of the stress intensity factor Mk for the design curve.