Study On Sound Field Measurement Of Elastic Structures Under Shallow Sea Channel Environment

Ship-radiated noise is an important feature to evaluate its concealment,and it is also an important parameter to evaluate its noise reduction effect and theoretical verification.Radiation noise measurement can provide an important reference for the design and improvement of ship.However,in the shallow sea environment,the influence of the multi-path interference on the measurement is very serious,so the measurement results are not accurate enough.So it is imperative to study the structure of radiation sound field measurement in shallow sea environment.In this paper,according to the problem of acoustic power and acoustic pressure of underwater elastic structure,the method of array beamforming is proposed to filter the sound field in the channel and improve the measuring accuracy.With the aid of finite element modeling,acoustic finite element analysis and a variety of pre and post processing software,acoustical finite element method of point source,spherical shell and cylindrical shell was established respectively under the conditions of hard submarine channel,Pekeris submarine channel and elastic submarine channel Model,different structures under different radiation field simulation.The beamforming characteristics of the vertical array and shaped array are also studied,and the filtering ability of the different beamforming methods for the interference of the channel boundary is analyzed.For the vertical array,the conventional beamforming,the Chebyshev beamforming and the lowest sidelobe beamforming were used for filtering,and the shaped array was filtering by the conventional beamforming.The simulation results show that the filtering characteristics of the beamforming methods in both arrays are effective.The elimination of the influence of the boundary verifies the feasibility of applying the array wavenumber formation method to the radiated sound power and sound pressure measurement in the channel environment.In this paper,the measurement methods of vertical array and shaped array beamforming are analyzed experimentally,and the special shaped measurement array is designed and fabricated.The radiation field of spherical sound source with channel pool and anechoic pool is measured.The experimental results verify that vertical arrays and shapes array beamforming methods radiation sound field measurements of flexible structures in a channel are performed.