Research On Vibration Characteristics And Dynamic Vibration Absorber Of Railway Track

Wheel/rail noise is the main source of railway traffic noise when the train is normal working. Noise radiated by the rail vibration is considered to be the main portion of wheel/rail noise in the frequencies blew 3000Hz. Studying in vibration characteristic of rail and improving a new method to decrease the vibration and noise become a key job of wheel/rail noise control.A finite elements model of rail is built in this paper. After model analysis in ANSYS, natural frequencies and modes is get. The result of experiment model analysis based on mechanical admittance method is coincident to the ANSYS results. Testing the vibration acceleration signal of rail top (lateral and vertical), rail middle (lateral), rail bed side (vertical) and rail bed middle (vertical) with DASP vibration testing system, calculation of signals obtains the power spectral density and frequency response curves of different position. The results indicate that the main form of lateral vibration is the whole rail's waggle with the axis at the intersection of neutral plane and symmetry plane, the main form of vertical vibration contains the vertical vibration arose by lateral vibration and the absolute vertical flexural vibrations of whole rail. Confirming 1072Hz and 2193Hz to be the most important control frequencies after the cohere analysis between vibration and noise signals.Calculate the optimum parameters of two freedoms damping dynamic vibration absorber with the method of optimum parameter designing. Results of vibration and noise experiment between the rail with and without damping dynamic vibration absorber indicate that the lateral damper can decrease 5.2 dB while the vertical can decrease 4.98 dB.Experimental method is used to study the relation between vibration of different position and noise and design a new simple and practical method but the method of treating whole rail as Euler or Timoshenko beam which is widely used by the most experts, but the result is improved to be effective.