Study Of Vibro-acoustic Characteristics Of Plate And Stiffened Plate With Viscoelastic Damping Treatment And The Optimization Of Reducing Plate's And Stiffened Plate's Noise

Because most contemporary ships are composed of plate structures , stiffened plate structures and damping plate structures, during researching their acoustic characteristics and vibrational characteristics, it is propitious to reduce ships' vibrational velocity and their noise. It's very important for practical application. Based on the aim for reducing the vibration and noise of plate structures , stiffened plate structures and damping structures, this paper studies their acoustic characteristics and vibrational characteristics on three aspects as structures' radiation acoustic power, structures' acoustic radiational model analysis , structures' acoustic transfer vector and structures' model acoustic transfer vector. The primary researching content and innovations are as follows:The acoustic radiative characteristics of plate structures and damping plate structures are studied by combining FEM(Finite element method) and BEM(boundary element method). Compiles an interface programme between ANSYS and SYSNOISE by using APDL language, which is used to storage all the notes' displacements that are on the structure under different frequencies. By importing this displacements' file to SYSNOISE can account structure's radiative acoustic output power. When researches the plate's radiative acoustic output power, gain the infections by comparing different structures' parameters as plate's thickness, area, material and boundary restriction. When researches the damping plate's radiative acoustic output power, gain the infections by comparing different damping layer's thickness, Young Modulus and density. The researches' results provide references for debasing and controlling structures' acoustic radiative characteristics.The structures' acoustic ratiative model is studied by combining FEM and BEM. The analysis on acoustic ratiative model compares the infection of different acoustic transfer medium and laid damp on the stiffened plate. The cost of acoustic ratiative model in water is bigger than it in air. The costs of vibrative velocity on acoustic radiative model in water are also bigger than them in air. It is effection that reduce the costs of structures' model participate in response function (MPF) with viscoelastic damping.The structures' acoustic transfer vector and structures' model acoustic transfer vector are studied by combining FEM and BEM. When analyze structures' acoustic transfer vector and structures' model acoustic transfer vector, can concretely give the acoustic pressure cost of specific field point which causing by some note or some element or some model when structures vibrate under specific frequency. It's important in practical studies. By comparing the infection caused by different areas of plates, different acoustic transferring mediums, different plate materials and different places of field points, can get the conclusion that the structures' geometrical areas, the places of field points, calculate frequency and the physical parameters of acoustic medium such as velocity, density influence the structures' acoustic transfer vector and structures' model acoustic transfer vector. Structures' material characteristic only effects the model acoustic transfer vector.