脆性破壊発生に及ぼす塑性拘束の影響の定量的評価

概要

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The plastic constraint condition affects the occurrence of brittle fracture. This effect is very important because many of the weld defects in beam to column connections are small cracks, although the material toughness is measured using a specimen with a deep notch. This paper shows the ability of the simplified model to predict brittle fracture under low plastic constraint conditions. Fracture toughness tests of SENB specimens with a shallow notch, and tension specimens (DENT and CNT) were performed and these specimens showed higher fracture toughness compared with SENB specimens with a deep notch due to a loss of plastic constraint at the crack tips. The Weibull stress approach and toughness scaling model were used to consider the effects of the loss of plastic constraint on the fracture toughness of the specimens. The corrected fracture toughness values evaluated by the toughness scaling model were found to be close to the toughness values observed in the tests as well as the values predicted by the Weibull stress approach.
社団法人日本建築学会の論文
2009-03-30