Study On The Relationship Between The Scale And Sound Insulation Characteristics Of Composite Hollow Sound Insulation Test Piece

Since 2008,China's high-speed trains have emerged,which greatly enriched people's travel modes.The problems that were difficult to travel,slow travel,and inconvenient travel have been fundamentally alleviated.At the same time,high speed train has made a huge contribution for the domestic economy growth.Although the advantages of high-speed trains are self-evident,the aerodynamic noise generated by the high speed train is very large,whether it is for residents along the line,passengers in the car or train drivers.It has a very big impact.At present,the high-speed trains deal with noise mainly by noise isolation.The sound insulation wall panels are used to block the noise outside the compartment,so that the noise cannot be further propagated.However,the structure of the sound insulation wall panel can be selected to maximize the noise isolation.The current major issues still need to be studied in depth.In this paper,the composite hollow test piece is selected as the sound insulation test piece.By changing the structure size of the sound insulation test piece and analyzing the influence relationship of the sound insulation quantity change,two research methods are adopted in the paper.The first is the experimental method,and the reverberation room method is used.Measurement of multiple sound insulation test pieces of different structure sizes,mainly by changing the area and thickness of the test piece to carry out comparative experiments,and controlling the sound insulation quantity of test pieces of different area sizes under the condition of controlling the thickness of the sound insulation test piece unchanged When the area of the sound insulation test piece is controlled to be the same;the sound insulation quantity of the test pieces of different thicknesses is measured and compared and analyzed.The frequency is divided into the low-medium frequency band and the medium-high frequency band,and the test pieces of the same thickness are analyzed for the variation of the sound insulation amount with the area in the two frequency bands.The second is the numerical simulation method.One of the test pieces is selected to establish a three-dimensional solid model,and the finite element software is introduced for modal analysis.Then the simulation results are analyzed,and the experimental results and numerical simulation results of the similar test pieces are compared and analyzed.Finally,the experimental results and numerical simulation results are used to draw corresponding conclusions,so as to provide prediction and guidance for the practical application of sound insulation test pieces in the future.The results show that when the thickness of the test piece is the same,the area of the test piece with the maximum sound insulation at three thicknesses is not the same;When the test piece area is the same,the sound insulation amount increases with the increase of the thickness of the test piece,that is,the sound insulation amount of the test piece with the thickness of 150 mm is the largest than that of the other thickness test pieces;The area of the test piece with the smallest amount of sound in the middle and high frequency bands is not the same;the sound insulation of the test piece fluctuates but rises continuously at low frequency,and the sound insulation of the test piece suddenly drops and the amplitude is large at high frequency.Comparing the experimental results with the numerical results,it is shown that the low-frequency range agrees well,but in the high-frequency range,the difference between the them is large.