Damping mechanism of noise damped wheel for high-speed railway vehicles

Abstract

The purpose of this paper is to clarify the damping mechanism of the wheel that we have developed. In high-speed railway vehicles, noise associated with speed increase is a problem. We have developed a new wheel that can damp the rolling noise radiated from the wheel. This noise damped wheel has a special device attached to the inner circumference of the rim, which consists of steel sandwiched with vibration absorbing rubber. The noise damping effect was confirmed by the wheel rolling test, but the mechanism was unclear. Therefore, we elucidated the vibration damping mechanism using FEM. Using frequency response analysis, the equivalent radiated power (ERP) was calculated based on the response speed and element area when a load was repeatedly applied at a specified frequency. By calculating the modal ERP for a specific frequency, the natural vibration of the wheel, which contributes significantly to that frequency, was clarified. From this result, it became clear that the developed wheel disperses the natural vibration modes. It was also found that the vibration is reduced by damping of the rubber that acts on the dispersed natural vibration. Based on these findings, we concluded that increasing the Young's modulus of the rubber would improve the damping performance.