Numerical vibro-acoustic analysis of railway wheels with and without damping solutions

This paper presents a vibro-acoustic characterization of a railway wheel in the frequency domain with and without damping solutions. From a simple vibrational measure where modal damping ratios are calculated, the sound pressure at a certain distance from the railway wheel is predicted, avoiding time-consuming and expensive acoustic measurements. The approach is based on FEM (finite element method) and makes use of the submodeling technique which consists of decoupling the calculation first into a structural response, and then into the acoustic emission. This decoupling allows damping in the structure to be introduced in terms of modal damping ratios instead of Rayleigh damping, a commonly used approach that is, nonetheless, not very accurate. Due to the use of infinite elements in the boundaries, the size of the acoustic mesh is reduced to an ellipsoid surrounding the structure, thus decreasing calculation time. The results are compared with experimental measurements with satisfactory agreement. Thus, the approach described becomes a powerful tool to compare different damping treatments and to make a decision on which solution could be adopted in a particular application. (C) 2012 Institute of Noise Control Engineering.