Nonlinear stochastic earthquake response analysis of primary-secondary systems with base isolation and shock absorption

In order to examine how nonlinear hysteretic restoring force of the devices of base isolation and shock absorption is able to influence the response of root-mean-square displacements for two-degree-of-freedom (2-DOF) primary-secondary systems,hysteretic restoring force of the two devices are expressed by a nonlinear differential equation with several parameters as variables.The earthquake ground motion is simulated as Gaussian white-noise process.The responses of root-mean-square displacements of both primary structure and secondary structure are solved by using the equivalent linearization method.The response statistics by varying parameters indicates that nonlinearity of base-isolation dominates the influence of the response of both primary system and secondry system,and that moderate nonlinearities of the two devices contribute to reduce both response.