Research On Coupling Vibration And Underwater Acoustic Radiation Characteristics Of Mechanical Equipment And Boat Hull

Controlling and reducing the coupling vibration of mechanical equipment and the hull structure is the primary link and basic guarantee for the ship to achieve quietness.When the mechanical equipment is running,the vibration energy is transmitted through the floating raft and the base and excites the shell,causing the shell to vibrate and radiate noise into the surrounding water medium.This is a very complicated process.Carry out research on the vibration transmission characteristics of mechanical equipment to the hull structure and the acoustic radiation efficiency of the shell,as well as the contribution of different unit and base vibrations to the radiated underwater sound,evaluation of submarine stealth performance,noise source identification,vibration isolation of mechanical equipment The design,the optimization design of the underwater acoustic radiation characteristics of the coupling between the mechanical equipment and the hull,and the repair and maintenance work of the warship all have their important practical requirements and theoretical significance.A lot of research work has been carried out on the dynamic modeling of the vibration isolation system of the ship's mechanical equipment and the analysis of the vibration isolation effect,as well as the underwater noise radiation characteristics of the shell structure,but there is still a lack of vibration energy in the mechanical equipment-installation support(Or vibration isolation device)-the complete consideration of the propagation process in the transmission path-hull structure-underwater acoustic field,lack of quantitative research on the contribution of different unit and base vibrations to radiated underwater acoustics.In this paper,on the basis of reviewing and summarizing the research status of vibration and hydroacoustic radiation problems at home and abroad,the mechanical equipment,the hull and the surrounding acoustic field are used as a large system for parametric theoretical modeling and numerical simulation.Calculation and analysis of influencing factors,revealing the general propagation characteristics of vibration and acoustic energy in the transmission path,and the internal relationship between the vibration isolation performance evaluation index and the underwater acoustic radiation evaluation index,in order to further establish a theoretical modeling and experimental modeling phase Combined,suitable for quantitative research methods of coupled vibration and underwater acoustic radiation characteristics of mechanical equipment and hull structure.First,based on the dynamic modeling of the traditional mechanical equipment and hull coupling system,the fluid-structure coupling of the hull structure and its external underwater acoustic field is taken into account,and the hull structure is expanded to include the liquid-solid coupling of its external underwater acoustic field Vibration structure,and comprehensively use the admittance analysis method and four-terminal parameter transfer method to solve the theoretical model,in order to further confirm and express the relationship between the vibration isolation performance evaluation index and the underwater acoustic radiation performance index from the mechanism,establish Theoretical basis and working basis.Secondly,based on the typical installation form of mechanical equipment in the boat,the cylindrical hull is used to simulate the hull structure,and a parametric analytical model of the mechanical equipment?floating raft device?cylindrical thin hull hull?underwater acoustic field coupling system is established,and the vibration of the coupling system is analyzed.Numerical simulation and influencing factors analysis of the energy transfer and underwater acoustic radiation characteristics were carried out,including the transmission power flow,vibration level drop and sound pressure of observation points in the underwater acoustic field,etc.The influence of structural parameters on vibration energy transmission and underwater acoustic radiation characteristics,the basic law of sound pressure at the field point,and the relationship between the underwater acoustic pressure and the transmitted power flow and vibration level drop of the hull.Finally,the comprehensive use of finite element,finite element/boundary element analysis methods,with the help of finite element software ANSYS and acoustic software Virtual.Lab for experimental modeling,by calculating the sound pressure of the observation point in the underwater acoustic field of the thin cylindrical hull structure,the theory The comparative analysis of the analytical and experimental simulation results further verifies the reliability of the relevant modeling theory and analysis results.