Study On Vibration Isolation System Of Mixed Floating Raft Based On Magnetorheological Damper

"If the sea cannot be made,it must be made by the sea." This is an iron fact and a lesson from blood.The heavy equipment such as ships is one of the important ways to achieve a maritime power.All countries in the world have invested a lot of manpower and financial resources in this.Acoustic stealth,as an important indicator of ship level,has attracted the attention of navies and researchers from various countries.Improving the stealth performance of ship sound has become a research hotspot now and for some time to come.Based on the vibration noise of the main and auxiliary submarines under low-speed navigation,this paper studies the hybrid floating raft vibration isolation system based on magnetorheological dampers,and obtains the time-domain curves of performance indicators such as system acceleration response and vibration level drop,and analyzes the fuzzy PID.The effectiveness of the control strategy was tested and analyzed on the vibration isolation system.In this paper,the mechanical admittance method and the four-terminal parameter method are first used to model the dynamics of a complex floating raft vibration isolation system.A magnetorheological damper is used as an actuator,and a parallel hybrid vibration isolation system is formed with a spring guide to achieve vibration isolation in the full frequency domain.The flexibility of the intermediate floating raft and the non-rigidity of the foundation are fully considered,and the boundary conditions of the subsystems at all levels are taken into account to establish the dynamic model of the system.Subsequently,the core component magnetorheological damper is analyzed,and the mechanical model of the magnetorheological damper is established.The mechanical model is calibrated with the data obtained from the mechanical test and verified model credibility with test data.Based on the mechanical model of the magnetorheological damper and the dynamic model of the system,the PID and fuzzy PID controllers are designed and simulated.The two control methods are compared and analyzed.The optimal control method is selected as the system control based on the simulation analysis results.Finally,the experimental analysis of a hybrid floating raft vibration isolation system based on a magnetorheological damper is performed to obtain the acceleration response curve and vibration level curve of the system under different excitation forces.The vibration isolation of the system is verified by the introduced acceleration level.The validity of the theoretical analysis is verified by comparison between modal experiments and simulation analysis.