Investigation On The Force Source Recognition By Matching Method For Underwater Cylindrical Shell

Underwater vehicle investigation has become an important part of marine research.The acoustic concealment of underwater vehicle is one of the most important performance,only by ensuring the acoustic concealment characteristics can the underwater vehicle not be detected in the water and guarantee the operational performance.The premise of ensuring the performance of acoustic concealment is to find and suppress the noise source inside the structure.This paper is based on this goal to study the strength identification of internal force source.This paper studied the strength identification of internal force source based on the principle of matching field.The finite element software ANSYS,SYSNOISE and Virtual Lab are used to simulate the excitation response of the underwater flat plate structure and single-layer cylindrical shells.A matching field force source identification technique is proposed for the problem of force source localization and strength source analysis by combining with matching field processing technology.Underwater structures are mostly cylindrical shell structures.So,this paper selected cylindrical shell as the test object.Firstly,a single-layer cylindrical shell model is established by using finite element software ANSYS.The acoustic and vibration characteristics and sound field characteristics under the single-source and multi-source excitation are calculated in the boundary element software SYSNOISE.Then,sound pressure copy field,vibration velocity field and radiated sound power are established.Based on the analysis of the vibration characteristics of the shell under different excitation conditions,the force source equivalence method was established according to the different excitation sources.Particle swarm genetic algorithm(GA)is applied to the searching process of force source.These data analysis is carried out for the search accuracy under different signal-to-noise ratios.The threshold conditions of sound pressure,vibration velocity and radiated sound power as matching factors are analyzed.Verifying the proposed force source identification matching field method,using the calculated data to establish the copy field for the genetic algorithm search.And the matching recognition is carried out under different signal-to-noise ratios.The matching results are compared with the simulation results of the BEM,verifying the correctness of the search algorithm that used.The purpose of this paper is to verify the feasibility of the proposed method.Single-layer cylindrical shell multiple force source excitation are tested in free-field poll.In the caseof a single source,the intensity and position of the excitation source can be accurately identified.This paper validates the accuracy and feasibility of the method of matching source field to identify the force source,and can provide the basis and guidance for the vibration and noise reduction of underwater structures.