Theoretical Analysis And Research On The Acoustic Characteristics Of High-Speed Train Based On Aluminum Alloy Profile

As far as our country's railway vehicle industry being developed at top speed is concerned, this thesis does prediction and control research on the vehicle interior low-frequency noise of the acoustic-structural system of the high-speed train, combining with the latest research achievements home and abroad; on the basis of the structural optimization and damping treatment of the vehicle body, the thesis analyzes the vehicle interior sound field and makes a conclusion of the prediction analysis and control methods for low-frequency structural noise inside the vehicle. It has important guiding significance for structural acoustic design of railway vehicle.In order to decrease the interior noise and vibration of the high-speed train, the carrier of acoustic vibration, i.e., the platform floor, is analysed and researched first in this thesis. Based on CAD/CAE software, the acoustic-structure vibration model is built up and by using the analytical method of finite element and boundary element, the vehicle structure is researched and the interior noise is analysed and forecasted.Firstly, this thesis introduces the general development of the vibration and noise reduction of high-speed train and the analysis of interior noise home and abroad. The mechanism of noise transmission and the resources of interior noises are described later. Secondly, because the primary vibration is propagated in via the platform floor, the large-scale aluminum alloy extrusions of the platform floor are researched and analysed, after the structure determination and parameters optimization, to make the stiffness maximum. Then, based on the modal analysis of the profiles and the testing results, the best positions where the vibration and noise reduction damping is sticked to the profiles are determined. The sticking damping is set as free damping, The test platform is built, and the effect of sticking damping is studied through test analysis.Then, this thesis establishes the finite element models of the high-speed train body structure and cavity acoustic, analyses the dynamic characteristics of the body structure and the acoustic modal characteristics of the cavity, and points out the probable frequency that may cause acoustic cavity resonance. By using the finite element method, the calculation in 10-200Hz hull structure within the scope of the vibration response in different position, through selecting observation in simulation under observation of incentive and vibration response differentia bodywork.Through the analysis of car-body harmonic response to a boundary conditions were analyzed and calculated inside the field observation plane in the interior 10-200Hz within the scope of the acoustic field distribution, and calculated the interior of selected six observation, through the pressure distribution characteristics of interior noise is analyzed. Then in aluminum alloy steel roof structure of pasting the damping and computing time inside the railcar, comparative analysis, thus draws the damping effect of paste.Finally, considering the air inside the body structure and the interaction based on a high-speed train sound - solid coupling model, and in the coupling condition of its dynamic analysis and interior acoustic analysis, further by selecting observation in the coupling reflects off the acoustic properties within the state.