Numerical Simulation And Experimental Veriifcation For Sound Insulation Performance Of Panel-type Structures

Cabin noise is an important technical indicator for the high-performance ships. In orderto meet the requirements for ship cabin noise limitations, the sound insulation performance ofsound-insulated structures should be studied. The computational methods for predicting theacoustic performance of typical sound-insulated structure in ship cabins are developed in thisthesis. Then the effects of structures and boundary conditions on the sound insulationcharacteristics of sound-insulated structures are investigated numerically.The wave analysis approach is used to predict transmission loss of single-layer infinitepanel and double-layer infinite panel and to investigate the sound insulation characteristics ofboth panels. The acoustic modes of room and panel structure are predicted by applying thenumerical methods based on finite element theory, and compared with the analytical results,which illustrated the accuracy of the finite element method (FEM) predictions.In order to predict transmission loss of panels, the rectangular pipe model is used, andthe finite element software ANSYS and Virtual Lab Acoustics are employed to calculate thetransmission loss of single-layer infinite panel and double-layer infinite panel. The goodagreements between numerical predictions with wave analysis approach results for thesingle-layer infinite panel and double-layer infinite panel verified the FEM. The FEM is thenused to predict transmission loss of stiffened panels, composite panels and sandwich panelsunder different boundary conditions, and the sound insulation characteristics of the panels areinvestigated. The rectangular cavity is used to simulate a ship cabin and the sound source isset as vibrating surface. By comparing the sound pressure level of the same field point indifferent conditions, the effects of structure and sound absorbent material on the soundinsulation characteristics of ship cabins are investigated.In order to verify the accuracy of FEM for the sound insulation predictions of panels,two-load method is used to measure the transmission loss of panels. Measurements agreewell with FEM predictions, which demonstrated that the measurement method and thenumerical method are both valid.