A research of a two degrees nonlinear quasi-zero stiffness vibration isolation system

For a vibration isolation system, the natural frequency of the system should be less than 0.707 times of the excitation frequency to make the isolation effective so it is necessary to reduce the natural frequency of the system. In this paper, the vehicle support system requiring good vibration environment with quasi-zero stiffness (QZS) isolator for loading the precision equipment is simplified into a two degrees vibration isolation system. On the basis, the dynamic differential equations of the system are established and the equations can be simplified as a 2-dimensional Duffing equation set. The differential equation set is solved with the harmonic balance method. The bifurcation, the jumping and other complex dynamic phenomena of the system are analyzed and the influence rules of system parameters are studied. The work can provide a theoretical basis for the design of quasi-zero stiffness vibration isolation system.