Dynamic Analysis of a Loading-Adapting Quasi-Zero-Stiffness Isolation System Based on the Rolling Lobe Air-Springs

Purpose To overcome the disadvantages that the loading capacity cannot be adjusted according to the variation of mass in traditional quasi-zero-stiffness system and invalidation of vibration isolation in low frequency region for a single air-spring, a loading-adapting quasi-zero-stiffness isolation system based on the dipteran mechanism is proposed by introducing rolling lobe air-springs coupled with friction and the imbalance of negative stiffness part. Methods First, the dynamic model is constructed for a single rolling lobe air-spring and the loading-adapting quasi-zero-stiffness isolation system according to the Second Newton’s Law and the Ideal Gas Law. Moreover, the Runge-Kutta method is applied to explore dynamic behaviors including the bifurcation, chaos and the co-existing periodic solutions with varying disturbing parameters. Meanwhile, the vibration isolation characteristics is investigated by employing the averaging method theoretically. Furthermore, a single air-spring and a loading-adapting quasi-zero-stiffness isolation devices are set up to verify the isolation performance experimentally. Results The theoretical analysis show the new bifurcation forms occurs in this system. In addition, the requirements of vibration isolation can be satisfied in low frequency region although the friction and the imbalance of stiffness are introduced in this system without affecting the isolation performance in high frequency range, illustrating the ideal robustness of the system. The experimental results also indicate a good agreement with the theoretical results obtained for the rolling lobe air-spring and the proposed loading-adapting system. Conclusion The findings in this work illustrates a better performance of loading-adapting quasi-zero-stiffness system than traditional quasi-zero-stiffness system and air-springs, which can provide reference for research and application about loading-adapting quasi-zero-stiffness isolation system.