Abstract
This paper deals with the ductile crack growth in the heat affected zone of butt welded joints which are made by multi-layer CO2 gas shielded arc welding and made with steel for building structure. The purpose of this study is to evaluate the ductile crack growth in heat affected zone under large cyclic deformation. The test welded joint whose heat affected zone has the inhomogeneity of strength and ductility was fabricated, and in order to confirm the ductile crack growth behavior in the heat affected zone, the large deformation cyclic loading test for notched element specimens taken from the heat affected zone was carried out. Then, FEM analysis simulating the loading test was carried out. It was found that the ductile crack growth behavior in the heat affected zone can be evaluated by using the ductile damage model proposed by the authors. As a result of FEM analysis, it was indicted that the ductile crack growth behavior in the heat affected zone was greatly affected by the strength inhomogeneity. FEM analysis was also carried out using the assignment of material properties to the heat affected zone as a parameter, and it was found that the ductile crack growth behavior can be evaluated even if the assignment of material properties to the heat affected zone is simplified, if the effect of the strength inhomogeneity on the strain distribution can be reproduced.
