Insert The Hose Sound Absorption Characteristics Of The Resonant Structure Study

With the development of industry and national defence, noise pollution has been a problem which is an urgent demand to be meet. Since the low frequency noise is always broad band, it is very difficult to restrain, which is concerned by more and more researchers.Sound absorption advanced in this dissertation is different from traditional structure for sound absorption. The broadband resonance sound absorption structure for low frequency on the basis of Helmholtz resonator, and the rigidity neck is superseded by the tube. The thesis mainly includes the following three aspects: analyzing the sound absorption characteristics of Helmholtz resonator with extended neck; studing the acoustical speciality of tube; calculating the parameter of sound abstract of the structure with tube and comparing with the data of experiment.The first aspect is contributed to analyze characteristic of Helmholtz resonators with extended neck. In this part, the Helmholtz resonators are applied to pipeline noise elimination and panel sound absorption, and the relation between parameters of structure and the transmission loss, sound absorption coefficient is gained.The second aspect is to discuss the acoustical speciality of tube. Based on the material studying, mechanics and acoustics, the characteristic of tube is analyzed to find the the relation between parameters and the wall's impedance of the tube.The last aspect is devoted to discuss the relation between the parameter and the transmission loss, sound absorption coefficient, and then the acoustical speciality of tube is compared with the data of rigid structure and experiment. It is found that the structure advanced in this dissertation shows more advantageous theoretics considered in this paper is correct.