- Title: Vibro-acoustic characterization of railway wheels: application to sandwich-type constrained layer damping solutions
- Defense Date: 01/07/2013
- Directors: Nere Gil-Negrete and Javier Nieto
The continuous advances in rail transportation has made it one of the most efficient forms of transportation today in terms of energy efficiency. Nevertheless, due to its expansion across the globe, environmental requirements have also become more stringent, especially those related to emitted noise. Along this line, an exhaustive study on predicting the amount of noise generated by trains and designing solutions for noise reduction found that among the various sources of noise, the railway wheel represents a major component. This attracted the interest of many researchers, and it has been concluded that increasing wheel damping is an effective method of reducing noise. In this sense, the concept damped wheel is equivalent to low-noise wheel.
This thesis focuses on developing a methodology for acoustically characterizing railway wheels, both with and without damping solutions. This methodology can serve as a flexible and computationally cheap tool that helps companies during the design stages of low-noise railway wheels.
Among the available damping solutions, the sandwich-type constrained layer damper presents a broader design application than other solutions, and it can be adapted to solve a wide range of noise problems. However, even though it is being used in operating railway wheels, an exhaustive study is missing. This thesis intends to fill this gap by carrying out a complete analysis of this solution, which involves understanding the damping mechanism, modeling it and determining the influence of the design parameters, and theoretically predicting its efficiency.
To that end, this thesis presents methodologies for (1) evaluating railway wheels without damping solutions, (2) numerically comparing different damping systems, (3) modeling and designing sandwich-type constrained layer damping solutions, and (4) theoretically predicting their effectiveness when they are attached to a railway wheel.