Abstract
For the simple vibration system that established the concentrated mass on the tip of the cantilever, we carried out elasto-plastic response analysis and examined the failure mode of nuclear equipment under earthquake loadings. As a result, the maximum response stress of the cantilever is less than tensile strength even if the input acceleration reaches more than 10 times of the acceleration to reach a yield stress. It is clarified that the threshold passage destruction do not occur under earthquake loadings.
