溶接殘留応力が脆性破壊伝播におよぼす影響について

概要

論文の詳細を見る
Brittle crack propagation in welding residual stress field will be intensely affected by the tensile and compressive components of residual stress. It mainly results from the fact that the strain energy release rate pertaining the energy condition for unstable fracture changes in accordance with the changes of pre-existing residual stress.In this paper, the strain energy release rate when a brittle crack propagates through residual stress field is calculated by assuming some simplified forms of residual stress distribution, and some experimental results are accounted on its grounds.As to the effect of welding residual stress, the following conclusions are obtained from the results of the calculations.1) The effect of residual stress decreases as crack length increases.2) Strain energy release rate responds to changes of pre-existing stress state but with some lags.3) The larger is the residual compressive stress between two neighbouring welding beads, the smaller the minimum value of strain energy release rate.4) The lower is the applied load, the more intense the effect of residual stress on brittle fracture and so a brittle crack should possibly be arrested or accelerated at a certain low stress level.5) As a rule strain energy release rate for a plate with finite width is larger than the one for infinite plate, and the difference between them increases as crack length or applied stress increases.