隅肉溶接トウ部の表面切欠からの脆性破壊発生特性評価

概要

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As a model of the stress concentrators in the welded structures, a wide plate test with stiffener was carried out, and the brittle fracture characteristics from a surface notch at the toe of the fillet weld was studied. The results of the investigation are summarized as follows. CTOD values obtained from the wide plate test are agreed well with those from COD test with a/ω=0.5, even for the very shallow surface notch in the wide plate test. It is confirmed from this results that CTOD criterion can be applied to elastic-plastic fracture from the surface crack in the highly deformed region. The brittle fracture strength from the surface notch at the fillet weld toe is evaluated using COD design curve, which is obtained by modifying WES 2805. The strain at the toe used in the evaluation is estimated for the average value in the cracked area. The strain concentration factor at the toe is caluculated from the elastic stress concentration factor by means of the modified Neuber's relation. Using such strain and COD design curve. the brittle fracture strength is well estimated.