Research On Radiation Sound Field Prediction Of Elastic Structures Based On The Coupling Of Ray And Wave Superposition

Predicting radiated acoustic field of elastic structures in sea is a concerned research area in underwater acoustics.Traditional acoustic radiation calculation methods are mainly aimed at free space or semi-free space,but few studies have been conducted in ocean channels considering interaction with ocean boundaries,especially the radiation acoustic prediction in the middle and high frequency band is still blank.This paper combines the ray theory and the wave superposition method.Using the vibration information on the structure surface,the corresponding structural sound source is equivalent to several virtual sound sources by configuring corresponding virtual sources,and then the prediction of the radiated sound field of the elastic structure in sea in the middle and high frequency band is realized.In the process of establishing the theoretical model of the ray combined wave superposition method,this paper proposes an optimization for the phenomenon that the prediction result of the radiated sound field under certain conditions is greatly affected by the small disturbance of the vibration information of the structure surface,which damages the stability of the numerical calculation.In the solution,in the process of solving the inverse problem,a stable functional is constructed by using the regularization parameters to the possible ill-conditioned equations,and the stable approximate solution of the ill-conditioned equations is solved by adjusting the values of the regularization parameters,so as to optimize the numerical calculation.Combined with the theoretical basis proposed in this paper,a prediction program of acoustic radiation by ray combined wave superposition method is compiled.After giving the corresponding reference scope of the ray wave superposition method,this paper verifies the validity of the ray wave superposition method from the perspective of the near-field calculation accuracy of the Green's function and the virtual source allocation strategy.After analyzing the accuracy of its prediction,this paper explains the selection criteria and error influence rules of the number of virtual sources and the ratio of the virtual source surface to the structural surface radius.Based on the completion of the above work,the paper analyzes the acoustic radiation characteristics of elastic structures in shallow sea environments.The analysis mainly reveals the characteristics of structural acoustic radiation from two aspects: the type of the sound source and the size of the source,which is mainly reflected in the fact that the radiated sound source generates a specific mode.In the radiated sound field,it is reflected in the attenuation and propagation of normal modes with different orders.The excitation intensity spectra of normal modes corresponding to structural sources and point sources have different distributions,but the spectral components are consistent,indicating a certain relationship.Finally,the experimental verification of the ray combined wave superposition method is carried out in this paper.The surface vibration information and radiated acoustic field of the elastic structure model are measured in a specific experimental environment,which effectively verifies the practicality and reliability of the ray combined wave superposition method.