Research On The Vibration And Acoustic Radiation Characteristics Of The Metro Wheels

The advantages of the subway commute are as follows:high speed, big capacity, low cost, light pollution, less land occupation, good security, which other means of transportation could not match, therefore subway commute is the best way to relieve the traffic jam of cities. However the problems of noise pollution and ambient vibration in subway transit are very serious, which could not be ignored. The wheel noise is the important part of railway noise, so reducing wheel vibration and noise is a very efficient measure to reducing the rail transit noise. Compared with the straight wheels, the S-shaped web plate wheels have obvious advantage in structural strength, mechanical properties and so on, but also have serious noise and vibration problem. So this paper makes a pertinent study on the characteristics of the S-shaped web plate wheel vibration and noise radiation.By using finite element method and boundary element method, the S-shaped web plate wheel vibration and noise radiation are researched as follows:(1) NURBS curve method was used to build the axial section of wheel, on this basis, using De Boer algorithm to write MATLAB programs for solving quadratic NURBS curve of wheel profile. The curve of wheel is controlled by control vertices and weight factor, which could easily be modified.(2) The finite element model of the S-shaped web plate wheel is established in Hypermesh. The natural frequency and modal shape of the subway wheel are investigated. The result shows that wheel vibration modes contain axial modes and radial modes. The displacement admittance on different parts of the wheel is studied.(3) The boundary element model of the subway wheel is established. The dynamic response is used as a velocity boundary condition in acoustic boundary element model(BEM) for noise radiation analysis. From this analysis, the surface sound pressure, sound radiation efficiency and radiated sound power are calculated.(4) The wheel profile is changed by modifying control vertices and weight factor. Based on this, the geometric parameters of web that affect the wheel vibration and noise radiation are discussed.