欠陥を有する完全溶込み溶接始終端部から発生する脆性破壊: 塑性拘束が及ぼす影響

摘要

A series of tests, which reproduced brittle fracture starting from the region around the terminations of CJP (complete joint penetration) groove welded joints, was conducted. The joint models under study were portion of welded beam flange-to-through diaphragm joints in beam-to-column connections. Various artificial defects were installed in the welded joints prior to testing. This paper describes the effects of plastic constraint on brittle fracture from the welded joints with the defects at the ends of CJP groove welds. Atoughness scaling model, which considers the effects of plastic constraint, was used for evaluating the occurrence of brittle fracture and was found to predict well the test results, compared with a conventional prediction method using fracture toughness Jc.%本研究では，欠陥を有する溶接始終端部から発生する脆性破壊を実験的に再現し，有限要素解析を用いて欠陥先端の応力状態を調べ脆性破壊の発生について考察した．また，Toughness scaling modelを用いて塑性拘束の影響を考察するとともに，_(ap)J_cを用いて脆性破壊が発生する試験体の曲げモーメントを推定した．以下に本研究から得られた知見を示す．