Analysis Of The Acoustics Of Infinite Double Sheets And Resonator Model

Because the sheet structure has the superior performance of sound insulation ability, easily processing, stability of acoustic performance, etc, It is widely used in aerospace, Construction Machinery, Vehicle Boat and other fields. With the development of acoustics, the Sound insulation ability of sheets have increasingly brought people’s attention. In order to explore the vibro-acoustic characteristic of sheet’s, This thesis is aimed to discuss the Sheet of sound transmission loss, calculate the acoustic characteristics of the infinite double sheets by theoretical deduction and numerical calculation.More details is as follows:Firstly, we deduce the formulas of the infinite double sheets by using the method of uniform distribution, the interaction force between sheets and connecting ribs is uniform distributed on the sheets, then, we deduce the sound transmission loss under the periodic boundary condition which using the space harmonics. From examples we can analysis the different parameters of the structures and the shape of the connecting ribs in MATLAB.In order to observe the influence of the connecting ribs more subtle, this thesis analyzes the sound insulation characteristics by using the periodic structure method in another way.During the analysis, the results need to deal in the method of truncation, when the two methods are proposed, we compare the two ways in MATLAB and conclude that:the periodic method is not different than the method of uniform distribution in the low frequency,However, the curve is oscillatory by the periodic structure method in the high frequency, the oscillatory curve reflects the microscopic properties preferably.Lastly, based on the sheets, we proposed a new model which is named resonator model with micro perforated, then the formula of sound transmission loss is deduced in the method of wave transmission, by means of examples,we conclude that:the resonator model with micro perforated has better performance than the infinite double sheets in the aspect of sound insulation, as well as, the sound transmission loss is not down to zero in the coincidence frequency. This results from the influence between the resonator and the structure itself.