Abstract
In this paper, the possibility of fatigue life prediction of spot-welded joint under two steps variable amplitude load was investigated. The constant amplitude fatigue tests for the spot-welded tensile shear and peel, bend specimens were carried out and the results were arranged by using the nominal structural stress. As a result of prediction using Miner's rule, the fatigue life of spot-welded joint under two steps variable amplitude load could be estimated by Miner's rule considering mean load. Further, it was suggested to be able to estimate the fatigue life without depending on the kind of joint. Therefore, the nominal structural stress parameter showed the possibility of evaluating the fatigue life of spot-welded joint under variable amplitude load.