Analysis of Perforated Sound Absorptive Structure of Trackside Sound Barrier

At low and medium speeds, wheel-rail rolling noise is the main noise source of rail transit. The low height sound barriers at trackside can better target wheel-rail noise, as show in Fiure.1. At the same time, sound-absorbing structures can be used to enhance noise reduction effect. In this paper, sound absorption structure is designed for wheel-rail noise peaks. The sound absorption characteristics of perforated sound-absorbing structure with homogeneous perforation have specific frequency selectivity. By combining different perforated sound-absorbing structure, it can be guaranteed that the barrier can meet the wideband sound absorption, and work well at the frequency of wheel-rail noise peaks. Different perforated plate and cavity are designed, and the sound absorption coefficient is calculated theoretically and numerically. The result of acoustic finite element impedance tube model and the electrical equivalent circuit model show that both the series and parallel structure can provide wideband sound absorption and several absorption peaks. Finally, the indirect acoustic boundary element method is used to analyze the noise reduction effect of common sound barrier and the sound-absorbing barrier on wheel-rail noise, as shown in Figure.2.