Vibro-Acoustic Analysis Of Composite Structure Lined With Porous Media By Wave Based Method

The Wave Based Method is a deterministic prediction technique to solve steady-state vibro-acoustic dynamic response.The method is computationally efficient and becomes convergence quickly.WBM equations for composite structure lined with porous media is derived to solve vibro-acoustic response.The Method dealing with boundary condction on the coupling interface is discussed specially and the implementation process of WBM is specified.The verification of WBM is carried out by numerical examples preparing for the analysis of acoustic coupling problems.First,double panels lined with porous media is solved by WBM,and the influence of parameter on the transimission loss(TL)performance considering three types of boundary condiction(BB,BU,UU)is discussed.It is found that along with the increase of porous media,the significant difference between lower frequency and higher frequency is found for UU panels,and for BU panels positive correction can be found besides some opposite appearance in mid-frequency.Along with the increase of air gap depth,UU panels and BU panels appears different.With the same depth of the whole double panels,UU panels shows the best TL in high frequency,and BU becomes best under the considering of the whole range of freqency.BB panels,however,show some advantages only in low frequency.Besides,the influence of porous media type is also discussed.Then,research on the vibration analysis of double panels lined with porous media is also implemented with WBM as well as the parameter effect.It is found that along the increase of porous media thickness,for UU and BB panels,the importing energy is mostly transported into porous media and air.Along with the increase of air gap depth,the feature of force resistance become dominant for UU bound and BU bound,and the amplitude of admittance for UU bound show positive correction,while BU bound show negative correction.It is also found that with the increase of depth of incident side panel,the energy of transmission panel for three types all shows a decreasing trend,indicating that the energy is dissipated by other parts of systerm.Due to the lack of efficient modeling procedure for the associated problems in sandwich structures,here the WBM is used to model the composite structure lined with porous problems.The results obtained here can be a good reference for the practical engineering problems.