Study On Vibration And Sound Radiation Characteristics Of Low-noise Wheel

Reduction technique of wheel/rail rolling noise is investigated through the finite element (FE) simulations and experiments, and focus is placed on examining the vibration characteristics of two damped wheels, namely a ring damped one and the noise shielded and vibration damped one developed lately. Sound radiation characteristics of the two damped wheels are tested in a semi-anechoic room, based on which the noise reduction of the damped wheels is assessed and the reduction mechanisms are investigated.First, the3D FE models are developed for the un-damped wheels that are taken as the referential wheels corresponding to the damped ones. Combining the eigen frequencies and modal shapes of the reference wheels calculated by the FE models and the frequency response functions of the wheels before and after installing damping devices on them, the noise reduction of the damped wheels is assessed and the reduction mechanisms are studied through the tests in a labratory. Furthermore, with both the numerical and experimental approaches, influences of shape of the wheel web plate on the vibration characteristics of a wheel are also investigated by comparing the results of the three different web types, i.e. straight, slope and double "S" types.Secondly, for the case of the wheel and rail in contact under static loads, the present work carries out the tests on the vibration characteristics of the noise shielded and vibration damped wheel and its referential wheel, and compares with those measured from the flexibly suspended wheels.The influences of wheel/rail contact are analyzed. Furthermore, the vibration frequency response functions of the wheel with straight web are measured in the flexibly suspended state and in the wheel/rail contact state under different loads. The mode damping ratios of the wheels under different conditions are determined using the half-power bandwidth method. Influences of the contact load on the vibration characteristics of the wheel are studied.Thirdly, in the flexibly suspended state, the sound radiation characteristics of the ring damped wheel and the noise shielded and vibration damped wheel are tested in the semi-anechoic room. Based on these tests, the noise reduction mechanism is investigated for the damped wheels. In the meantime, the sound radiation characteristics of the wheels with three different web types are compared.Finally, the sound radiation characteristics of the noise shielded and vibration damped wheel with straight web are tested in the flexibly suspended state and the wheel/rail contact state. The noise reduction of the wheel is in detail analyzed for the wheel and rail in contact.