Study On The Influence Of Composite Floor Parameters On Sound Insulation Performance And Interior Noise Of Train

In order to better serve the social economy,the speed of high-speed trains is gradually increasing,and the problem of vibration and noise has also become prominent.Research has shown that high-speed train interior noise is formed by the transmission of external noise such as wheels and rails to the interior of the train through transmission,etc.Therefore,controlling the sound transmission path is of great significance for interior noise reduction.Taking the high-speed train floating floor structure as the research object,and for the purpose of noise reduction,this thesis analyzed the modal and sound insulation performance of the high-speed train composite floor structure,then analyzed and optimized the subsystem parameters of the main sound transmission path.The research results can provide a reference for improving the sound insulation performance of the composite floor and reducing the noise in the train.The research content of this paper are as follows.First,based on the modal theory,the effect of different boundary conditions and areas on the sound insulation performance of the aluminum plate is studied,and it is found that the different boundary conditions and areas mainly affects the low frequency sound insulation performance of the plate structure.As the board area increases,its low-frequency sound insulation characteristics gradually approach the unconstrained small-area board,so the use of free boundary conditions to establish a floor model can better fit the sound insulation performance of the car body floor.Combined with the verification of the free boundary conditions and the FE-SEA method in the case of aluminum profiles,the sound insulation prediction model of the composite floor was established,and the sound insulation frequency characteristics and sound transmission paths were respectively analyzed.Secondly,study the influence of the parameters of each subsystem on the path on the sound insulation performance of the composite floor along the structural sound transmission path.The results show that changing the inner floor parameters and wood bone spacing has a significant impact on the sound insulation.The influence of the inner floor parameters on the sound insulation performance is density,thickness,and stiffness in descending order.Increasing the wood bone spacing can effectively improve the sound insulation performance of the composite floor in the intermediate frequency.Changing the aluminum profile parameters has little effect on the sound insulation performance of the composite floor.Changing the thickness of the upper and lower plates only affects individual frequency bands.Changing the thickness and angle of the ribs has a relatively obvious effect on the sound insulation performance.Adding damping and damping layers mainly has a greater impact on the sound insulation performance of the sound insulation trough area.Adding damping and damping layers mainly has a greater impact on the sound insulation performance of the sound insulation trough area.Combining the above analysis,optimization suggestions such as changing the inner floor parameters,wood bone spacing,adding damping and vibration reduction layers,etc.Then,based on the MMA,the parameters of the wooden inner floor and the sandwich inner floor are optimized under the conditions of the deformation amount and the total mass of the composite floor under a given load,and combined with the optimization suggestions in Chapter 4,establish an optimized composite floor sound insulation prediction model for verification.The results show that the sound insulation of the four optimized sound insulation prediction models has improved significantly,and compared with the sandwich inner floor,the sound insulation performance of the wooden inner floor has a greater advantage.Finally,based on the statistical energy method,a high-speed train noise prediction model is established,the key model parameters are obtained after theoretical calculation,and the optimized composite floor is loaded to evaluate the noise reduction effect in the train.The results found that the noise reduction in the car is obvious,and the noise reduction effect of each composite floor on the interior noise is consistent with its own sound insulation performance.When the speed is increased,the contribution of the noise power in the direction of the floor gradually decreases.The difference in noise in the train caused by the four optimized composite floors has gradually decreased.