Reduction of First Excursion Probability of Mechanical Systems under Earthquake Excitations by Inelastic Restoring Force-Deformation Relation

Abstract

Important mechanical systems installed in nuclear power plants and other industrial facilities must be designed not to lose their performance during and after destructive earthquake excitations. In this paper, reduction of the first excursion probability of such mechanical systems with inelastic restoring force-deformation relation is examined. First, the first excursion probability of inelastic mechanical system is estimated from experiment using stationary random noises as input. Next, relation between restoring force and deformation is identified from simulation technique using hysteresis loop obtained from experiment. Next, effectiveness of reduction of the first excursion probability for mechanical systems subjected to earthquake excitation is examined by using nonstationary artificial time histories. Finally, obtained results are examined by theoretical technique using equivalent linearization method. It is concluded that the first excursion probability of inelastic mechanical system is smaller than that of elastic system.