き裂近傍に円孔を有する材の変形挙動と脆性破壊強度

概要

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The effects of circular hole located near crack tip on deformation and brittle fracture were investigated analytically using F.E.M. and experimentally. It will be important to investigate these effects in relation to the significance of defects in welded structures. Stress and strain distributions at the vicinity of crack tip were calculated for various locations of hole. The results showed that stress and strain between crack tip and hole become extremely large due to the effect of hole. Experiments were also conducted for the same model of F.E.M. calculation. It was found that brittle fracture initiation is almost independent of hole location, when the diameter of hole is small in comparison with the crack length. And the estimation of fracture initiation stress for this experiments can be made by COD-criterion. It also showed that stress and elongation at completely fracture of specimen with hole are dependent of hole location and are never lower than these of specimen without hole. For more general circular holes, the effects of circular hole location and size on brittle fracture behaviors were preparedly considered.