二段多重変動振幅荷重下のスポット溶接継手における疲労限度以下荷重による疲労損傷

抄録

Fatigue damage of spot-welded joints by loading range below the fatigue limit under multi two steps variable amplitude load is estimated by the degree of influence α, according to the modified minor's rule. However, the verifying by experiment is not sufficient. The crack growth rate of the high loading range under variable amplitude is equal to the crack growth rate in the constant amplitude. Therefore, the crack propagation length caused by the high load ranges is the same as that of the constant amplitude. In this study, the crack length in single spot-welded joints under constant amplitude was observed. As a result, fatigue damage due to loading range below the fatigue limit can be evaluated by using the degree of influence α.