A Novel of Low-Frequency Vibration Isolation with High-Static Low-Dynamic Stiffness Characteristic

The efficiency of quasi-zero stiffness vibration isolator will decrease when getting overloaded and underloaded. Given the variability of load in general engineering application, this paper aims at presenting a newly designed type of vibration isolation system with positive stiffness in parallel with elements of negative stiffness, which has variable carrying capacity. The vibration isolation performance of system requires overall analysis. Firstly, static analysis is applied to obtain the optimal vibration isolation parameters of the system at the equilibrium position and to verify the high-static low-dynamic stiffness characteristic of the system. Then, the nonlinear dynamic equation of the system is established. Meanwhile, the influence of excitation amplitude on the transmissibility of the system is analyzed under three different conditions by harmonic balance method. Finally, the response curves of the system to sinusoidal excitation and multi-frequency excitation are analyzed by numerical simulation. The result of numerical simulation shows that the vibration isolation system still has good low-frequency vibration isolation characteristics when dealing with different loads. The problem of poor vibration isolation performance of general quasi-zero stiffness isolators under load changes is well solved.