Isolation performance of a quasi-zero stiffness isolator in vibration isolation of a multi-span continuous beam bridge under pier base vibrating excitation

Abstract

This paper considers a vibration control problem for a multi-span beam bridge under pier base vibrating excitation by using nonlinear quasi-zero stiffness (QZS) vibration isolators. Three linear springs are needed to construct a nonlinear vibration isolator with quasi-zero stiffness. The vibration of the multi-span beam bridge under control and without control is governed by partial differential equation and several ordinary differential equations which are derived from Galerkin method. Modal superposition method with numerical modes of the structure and an iterative method are combined to predict the vibration response of the structure under pier base excitation. The influence of the quasi-zero stiffness vibration isolators on isolation of multimodal vibration of beam bridge is studied. The absolute motion transmissibility is proposed to evaluate the performance of the quasi-zero stiffness vibration isolator and is compared with an equivalent linear viscoelastic vibration isolator. The results demonstrate the effectiveness of the these two potential control method as well as a good control performance in suppressing vibration for high frequencies. But at low frequencies, only the quasi-zero stiffness vibration isolator can reduce the vibration amplitude of the beam bridge around the resonance frequency region. The effects of each control parameter on the absolute motion transmissibility of steady-state behaviors are investigated for a better isolation performance.