Dynamic Behavior of a Simple Rolling Seismic Isolator with a Position Restoring Device

Abstract

Herein, the behavior of a rolling type seismic isolation system with a position restoring device (PRD) is investigated, for alleviating problems such as rapid convergence and position restoration. The equation of motion is derived by modeling the behavior of the seismic isolation system, and the seismic characteristics according to the design variables of the PRD are investigated through numerical analysis. The vibration characteristics of the equation of motion show nonlinearity and depend on different variables. Numerical analysis was performed by using the fourth and fifth order Runge–Kutta method, and the vibration characteristics were analyzed with respect to the design parameters in the rolling type seismic isolation system with PRD, and compared to a model without PRD. In the model with PRD, numerical results show that the vibration suppression capability of the earthquake and the position restoration after disturbance are improved compared to those of the model without PRD. In addition, the rolling type seismic isolation system had nonlinear characteristics at specific frequencies, where the response increases suddenly and harmonics occur. This phenomenon can be controlled by the ratio of mass to stiffness and the damping coefficient, showing that the mount system can be designed to avoid resonance through optimal design.