新しい局部COD仮説の提案とその溶接部への適用(昭和59年度秋季全国大会論文発表講演論文)

概要

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Fracture toughness of welds has been usually evaluated, based on COD tests developed for homogeneous material. However, since mechanical heterogeneity caused inevitably in welds considerably influences crack opening behaviour, critical COD calculated according to the conventional method does not necessarily represent an appropriate fracture toughness parameter of material in the vicinity of crack tip. In the present study, at first, "Local COD criterion" has been proposed newly as an appropriate fracture criterion of welds with mechanical heterogeneity. In order to clarify the availability of the new criterion, bending COD tests and tensile tests of notched-welded plate have been conducted, using specimens extracted from undermatched and evenmatched weld joints of HT80 steel. FEM analyses have been also conducted in order to characterize the deformation behaviours of these specimens. From the experiments and analyses, in the welded joints with notch existing along fusion line, Local COD δ_L defined newly in our study is proved to control strains in the vicinity of crack tip, and applicability of Local COD δ_L as an appropriate fracture characteristic parameter is clarified. Moreover, it is suggested that fracture performance of welded joints with mechanical heterogeneity should be evaluated, based on Local COD criterion proposed in the presnet study.
社団法人溶接学会の論文
1984-08-05