New insights into the damping characteristics of a typical quasi-zero-stiffness vibration isolator

A typical quasi-zero-stiffness (QZS) vibration isolator composed of two lateral springs and a vertical spring has been widely studied in previous literature, in which the dynamic equation is usually formulated with linear viscous damping. However, in practical applications, the damping may be generated from many sources and thus deserves special study. In this paper, a dynamic model with consideration of three main damping generation mechanisms is established to give further insights into the damping characteristics of this typical QZS isolator. The dynamic response and stability are analyzed based upon the newly formulated dynamic equation. The effects of the damping characteristics on the vibration isolation performance are investigated. It is shown that the QZS isolator can exhibit hardening or softening damping properties by tuning parameters of the three damping sources, and the hardening damping is beneficial for the overall isolation performance.