An innovative X-shaped vibration mount with tunable quasi-zero-stiffness property

Passive vibration isolation is always preferable in many engineering practices. To this aim, a novel, compact, and passive vibration isolation mount is studied in this paper. This novel mount is adjustable to different payloads due to a special tunable oblique spring mechanism, and of high vibration isolation performance with enlarged stable quasi-zero-stiffness (QZS) range. The X-shaped structure has been well studied recently due to its excellent nonlinear stiffness and damping properties. In this work, it is for the first time to explore the utilization of the negative stiffness property within the X-shaped structure such that the designed X-structured mount (X-mount) can have obviously larger vibration displacement which maintains QZS property. A special oblique spring is thus introduced such that the equivalent stiffness of the X-mount can be much easily adjusted according to different payload. Systematic parametric study is conducted to reveal the enlarged QZS effect. A prototype and experimental validations are implemented to validate the theoretical results. It is believed that the X-mount would provide an innovative technical upgrade to many existing vibration isolation mounts in various engineering practices and it could also be the first prototyped mount which can offer adjustable QZS and adjustable loading capacity conveniently.