Theoretical Design and Dynamic Analysis of a Quasi-Zero Stiffness Device Using Precompressed Springs as Negative Stiffness Component

Based on the principle of parallel connection of positive and negative stiffness structures, a new quasizero stiffness (QZS) isolation device is proposed in which the negative stiffness structure is designed by a nonlinear precompressed spring system. The mechanical model of the device is dimensionless, and the parameter conditions required to achieve QZS at the static equilibrium position are derived. The agreement between the theoretical mechanical model and the experimental mechanical model of the device is further verified by static experiments. The dynamic model of the QZS system is investigated by using the approximate analytical and numerical methods of nonlinear vibration, which reveals the influence of the device parameters on its nonlinear dynamic characteristics and vibration isolation performance. Shaking table test were conducted to compare and analyze the dynamic response characteristics and isolation performance of the QZS system with the equivalent linear system. The results showed that the new device can effectively extend the isolation frequency range, reduce the isolation amplitude, and have good isolation performance.