Design of nonlinear metal rubber isolator subjected to random vibration

In this paper, a strategy to analyze the response of nonlinear metal rubber (MR) isolator under random vibration is proposed. And the stiffness and damping coefficient of MR isolator are designed to achieve broadband vibration efficient isolation. Firstly, the dynamic model of isolator is established considering the nonlinear characteristics of MR, and the effects of parameters on transmissibility are analyzed. Then, the Harmonic Balance Method is adopted for the numerically study, and the response of a nonlinear MR isolator subjected to random vibration is investigated. Next, the influence of parameters on the random vibration response are analyzed, and a design procedure is proposed to optimize the parameters for better vibration isolation efficiency by genetic algorithm. Finally, random vibration experiments are conducted for verification. It is demonstrated that the use of a numerical model in design procedure has been validated against experimental results, which can be extended to design other isolators with nonlinear stiffness and achieve a refined understanding of the nonlinear phenomena to a certain extent. Based on the proposed numerical model and design procedure, the obtained MR isolator has achieved high vibration isolation efficiency around 80% in three directions.