Study And Improvement On The Acoustic Performance Of Floor Of High-speed Train

With the development of high-speed railway technology,the speed of high-speed train in our country is higher and higher,but the noise caused by the increase of the speed becomes a major obstacle to improve the comfort of trains.Therefore,the vibration and noise reduction of high speed train has become an important research topic,and the improvement of the sound insulation property and the acoustic radiation property of the train plate plays an important role in the vibration and noise reduction of the train.At present,the experimental method is widely used by many engineers to study the acoustic properties of train plates.The results of this method are very accurate,but a lot of laboratory equipment and time will be needed.Therefore,the method of combining theory and simulation is used in this paper to analyze the acoustic performance of the inner and outer floor of the train.Time and the cost of laboratory equipment will be saved by using this method and the effects on acoustic performance of floor caused by the change of structural design variables can be discussed in detail.Then the design variables are optimized.Firstly,the sound insulation prediction model of single layer aluminum plate is established and the simulation results are compared with the experimental results to verify the validity of the simulation model.Then,according to the method of numerical simulation,the acoustic properties and stiffness of three commonly used aluminum profiles are compared and analyzed.The results show that the triangular aluminum profile is superior to the other two structures in acoustic property,bending rigidity and sound insulation stability.Then,the acoustic property of pure wood floor and sandwich panel under the same surface density is compared.In addition,the acoustic property of inner floor with different layers of damping is compared.The results show that the property of sandwich panel is very well when one layer of damping is inserted in the wood layer of the sandwich panel.Then the characteristic parameters of the inner and outer floor of the train are extracted and the parametric model of the inner and outer floor of the train is established based on the characteristic parameters.Taking the characteristic parameters of the inner and outer floor of the train as design variables,the sensitivity of the acoustic performance of the plate to the design variables is analyzed in wide frequency domain and narrow frequency domain respectively based on the finite difference method.The influence degree and direction of each design variable on the acoustic performance of the floor are clarified.Finally,according to the analysis results of the sensitivity of the characteristic parameters on the acoustic performance of the interior and exterior floors,the characteristic parameters which need to be optimized are determined.Then,the thickness of all layers of inner floor and the density of the wood layer and rubber layer are optimized.The thickness of the upper and lower panels,the thickness of the ribs and the angle of the ribs are also optimized.According to the sound insulation under different frequency,the average of sound insulation and the depth of the sound insulation trough of the floor with different parameters,the optimal values of the parameters are founded.The sound insulation of after optimization floor and no-optimization floor is compared to verify the effectiveness of the optimization method.