Using impulse acoustic response to evaluate the efficiency of rail absorbers

Abstract

The paper deals with laboratory measurements and analysis of the acoustic response of a rail equipped with various rail absorbers during impulse excitation by mechanical shock. The aim of the research was to design and verify an experimental methodology enabling an objective comparison of the acoustic properties of various design solutions of rail absorbers in controlled laboratory conditions. The excitation of the test sample was realized by the impact of a steel ball of defined mass from a constant height onto the rail head, while the resulting acoustic response was recorded using a measuring system with a calibrated measuring path. The
measured signals were subsequently evaluated in the time, frequency and time-frequency domains using the analysis of the measured impulse response. Particular attention was paid to the evaluation of the maximum sound pressure levels, the course of the response attenuation and changes in spectral characteristics after the installation of the absorbers. The results
demonstrate that the proposed methodology allows for reliable identification of differences in the acoustic behavior of individual absorbers and provides a suitable tool for their laboratory evaluation, development and optimization before deployment in railway operations.