WELD SHAPE EFFECT ON DUCTILE CRACK INITIATION IN WELD JOINTS SUBJECTED TO SEISMIC BENDING AND CONTROL EFFECT BY TOE GRINDING

Abstract

The welded joints of steel structure often accompany the high strain concentration and stress multiaxiality. Especially in the case of welded joints which subjected to bending during earthquakes, there is a possibility that a ductile crack occurs in the toe and the crack becomes the trigger of brittle fracture. In this study, the weld shape effect on ductile crack initiation and the control effect which produced by toe grinding were investigated through the cyclic loading tests of cross joint specimen and nonlinear FEM analyses on the specimen. As a result of loading test, the weld shape effect on ductile crack initiation at toe was confirmed. From the analytical investigation, the influence of the toe radius, the bead shape, and the base metal wastage accompanied with toe grinding were revealed. In particular, it was shown that the toe radius strongly affects on the risk of ductile cracking and toe grinding is effective to control the risk.