引張残留応力場からき裂が伝ぱんする場合の溶接残留応力場の再分布に関する研究

Abstract

An experimental investigation was conducted to clarify the behavior of residual stress redistribution caused by fatigue crack propagation itself initially through compressive residual stress field. Test specimens were prepared from HT80 steel plate and two parallel welds comprising one pass along each side of the specimen were applied by electron beam welding to induce centrally located compressive residual stress field.The results obtained from fatigue crack propagation tests were reviewed comparing with the results from sawcut simulating a propagating crack. While the crack propagated in the initial compressive residual stress field, the initial distribution of residual stress was maintained until the crack tip reached tensile field in the vicinity of the weld bead. However, as the crack propagated beyond compressive field and crack tip entered into the tensile field, accompaning the residual crack opening just behind of the crack tip, progressive redistribution of residual stress was occurred.