負荷形式の異なる引張せん断型レーザ接合継手の疲労強度評価

抄録

In the automobile industry, the thinned materials were applied to reduce the weight of the car body. Thus, the application of high-strength steel and resin material are currently expanding. At the same time, it is nessesary to develop a new welding method. The laser welding has attracted attention to weld high speed and low heat input to high-strength steel, So, the fatigue characteristics and a fracture mechanism of laser welded joints to high-strength steels are important from the viewpoint of reliability and safety. However, there researches of the joints in the automobile bodies are limitted, and it is required to expand the application range of laser welding in the future. Therefore, in this study, the fatigue properties of single lap laser welded joints were evaluated. Moreover, this study was focused on the loading mode of the lap joint, the pure tension-shear type in which the jig is restrained in the welded area was created and compared to the conventional lap joint. As a result, the static and fatigue strength of the joint was improved by the pure tension-shear type restraining the jig. In addition, the fatigue life of each joint was not uniformaly evaluated by the equivalent stress intensity factor ΔK_eq.