鉄道車両用台車枠の実溶接形状を考慮した応力解析

抄録

Railway bogie frames are welded structures, and there are stress concentrations such as weld toes, internal defects, and weld metal in the weld joints. In this study, ten weld joints were selected from the cross-sectional observations of the joints in actual bogie frames where fatigue cracks had occurred, and stress analyses of them were conducted. As a result, the stress was the highest at the weld toes, which corresponded to the actual crack initiation location. This suggests that fatigue crack initiation is more affected by the local shape of the weld toe than by internal defects in the weld or the shape of the weld metal. In fatigue design of welded joints for railway bogie frames, it is appropriate to use edge type gauge stresses at weld toes and to use actual bogie frame models with an element size of 16 mm to obtain the edge type gauge stresses in FE analyses. Moreover, the cracks were thought not to propagate from the overlaps and weld cracks from calculation results based on the fracture mechanics.