Bifurcation and chaos analysis of the floating raft vibration isolation system with quasi-zero-stiffness isolators

• Published in: Journal of Vibroengineering Vol. 27; no. 2; pp. 360 - 376
• Main Authors: Fang, Ming, Shi, Zhengong, Xing, Shuo, Zhang, Miao, Li, Zhipeng
• Format: Journal Article
• Language: English
• Published: JVE International Ltd 01.03.2025
• ISSN: 1392-8716; 2538-8460
• DOI: 10.21595/jve.2025.24486

This paper presents an investigation into the nonlinear dynamic behaviors of the floating raft isolation system coupled with quasi-zero-stiffness isolators subject to multiple disturbance sources. First, the coupling effects between the excitation source and isolation system are considered. Also, the floating raft isolation model under multiple excitations and its motion equation are deduced, and then the dynamic responses are mainly investigated by using the techniques of time history diagram, spectrum diagram, phase diagram and Poincaré map, and the bifurcation diagram. Finally, the bifurcations of the mechanical isolation system with different parameters are analyzed through numerical methods, especially the effect of center distance and mass ratio. The result predicts that the floating raft shows an alternate phenomenon of periodic motion, quasi-periodic motion, and chaotic motion when the center distance and mass ratio vary. The motion state of the floating raft vibration isolation system is more sensitive to the mass ratio than to the center distance. The horizontal and rotational response of the system becomes very intense in the chaotic state, and the response amplitudes in the horizontal and vertical directions reach the same order of magnitude. Above all, the dynamic characteristics can provide the theoretic supporting for the dynamics, vibration control and its parametric optimization of the floating raft isolation system coupled with quasi-zero-stiffness isolators. This study will lay down the requirements for the engineering design and application of floating raft isolation equipment in large vessel.