On the characteristics of a quasi-zero-stiffness vibration isolator with viscoelastic damper

Quasi-zero-stiffness (QZS) vibration isolators have been widely studied in previous literature, in which the viscous damping was adopted. In this paper, the QZS isolator with viscoelastic damper is studied, to seek an approach for further improving the isolation performance. The governing equation of the QZS isolator with viscoelastic damper (QZS-VED isolator) is formulated. The dynamic response is analyzed analytically and numerically. The transmissibility characteristics with varying key parameters are investigated, accompanied by comparison with the conventional QZS isolator, to demonstrate the advantages of the QZS-VED isolator. It is revealed that the damping ratio can be optimized to attain the lowest peak transmissibility and meanwhile the roll-off rate of high frequency transmissibility is twice that of the conventional QZS isolator, which implies superior isolation performance both around the resonant frequency and at high frequencies.