Dynamic Behavior of Nonlinear Rolling Isolation System

Dynamic Behavior of Nonlinear Rolling Isolation System

Most of the isolation systems are in linear system wherein the isolator has fixed vibration period. When structures with these linear isolators are located near a certain fault, it may cause resonance and large displacement response. For such, nonlinear isolation system can avoid the situation. In this study, an eccentric rolling isolator is used, and a parameter alpha(α ), which is the eccentricity of the mass block to the radius of the rolling device, was investigated. If the parameter alpha is not equal to zero, the dynamic response is said to be in nonlinear rolling behavior. The equation of motion of the isolation system was derived. The frequency of the isolator increases with the parameter alpha under the same initial displacement. The influence of the said parameter to the effect of isolation was scrutinized. Finally, the feasibility of the proposed isolation device has been verified numerically. From the obtained numerical results, the frequency of the nonlinear rolling system varies with the amplitude of vibration. Therefore, these isolation systems cannot only avoid resonance but also decrease well the response of structure.