モードII負荷を受ける切欠きからの延性き裂発生の機構

概要

論文の詳細を見る
This investigation deals with the mechanism of ductile crack initiation from a notch under mode II loading on a weldable structural steel SM41A. Under mode II loading, a notch root becomes acute and ductile crack initiation in shear type occrs at the region of the acutenotch tip by large shear deformation. The ductile crack initiation occurs in two stages. In the first stage, the crack is initiated ahead of the acutenotch tip by shear decohesion, and in the second stage, the crack emanates fro the tnsion side of the surface of the first stage crack under low stress tfiaxiality. It seems to be difficult to predict analytically the shear type crack initiation fro a notch under mode II loading, because of the intense concentration of strain at the acute notch tip and the coplexity of stress history of material lelments around notch tip. From the mode I loading tests of the specimens subjected to mode II pre-loading, it is found that the ductile crack initiation under mode I loading is promoted hy mode II pre-loading. This result suggests that, at the notch tip region under mode II loading, soe microscopic damage other than voids is produced, though unobservable by an optical microscope.
社団法人日本材料学会の論文
1989-09-15