Study On Acoustic Radiation Prediction Method For Underwater Multi-cabin Elastic Structure

This paper mainly studies the method of acoustic radiation prediction for underwater multi-cabin elastic structures.The main research frequency band is low frequency.Firstly,the acoustic radiation efficiency of underwater multi-cabin model is calculated by numerical simulation using finite element method.Then the vibration response of the structure surface is obtained by arranging a certain number of vibration sensors between the ribs of the underwater multi-cabin model,and the vibration data and sound field data of the underwater multi-cabin model are obtained by experimental measurement.Finally,based on the transfer method of acoustic radiation efficiency,the radiated acoustic power of underwater multi-cabin elastic structures is predicted by combining numerical and experimental results.A simple cylindrical shell model is used to study the effect of boundary conditions on acoustic radiation efficiency.The section where the excitation position is located is intercepted,and the influence of the boundary conditions of different baffles on the acoustic radiation efficiency is studied by adding baffles at the two ends of the section.The effects of different excitation positions on the acoustic radiation efficiency of underwater multi-cabin structures are mainly studied.Under the premise of keeping the excitation form and the same magnitude,the acoustic radiation efficiency of the whole model is basically the same when the excitation is applied in the same section.The excitation efficiency of the whole model is slightly different when the excitation is applied in different sections.After numerical simulation and experimental comparison,the overall trend of sound radiation efficiency under various working conditions is basically consistent with the magnitude.In addition,the sound radiation efficiency obtained by measuring the sound radiation efficiency at different excitation locations in the same cabin section is better for mutual prediction of sound radiation,so that the sound radiation efficiency is mainly related to the structure itself when the excitation force is close to the size and distribution of the excitation force.The vibration data of different cabins are collected and the sound radiation prediction of the cabin model is carried out separately under the strong excitation of single cabin section through various working conditions.It is found that the predicted results of single cabin vibration data are basically the same as those of the whole structure.Therefore,the sound radiation of the whole model can be approximately predicted by using the vibration data of single cabin.The method of improving the efficiency of finite element numerical calculation is also studied in this paper.In the finite element numerical simulation,especially in the calculation of large-scale models,it is necessary to simplify the calculation and improve the efficiency.The research results show that this paper has certain reference significance for the prediction of acoustic radiation of underwater multi-cabin elastic structures.The use of symmetry,the surface excitation meets the actual circumstance better than line excitation and some measures,such as the selection of effective fluid domain,and the simplification of the fluid-structure coupling of the ribs between double shells,are effective and practical technical measures in numerical calculation.