Design and Experiment of a Railway Noise Barrier Based on the Phononic Crystals

The increasing operating speeds and service frequencies of rail transit systems have posed unprecedented challenges to the acoustic environmental quality adjacent to railway alignments. Noise barriers, as the most effective solution for mitigating rail transit noise, currently represent the predominant noise reduction measure in this field. However, the continuous enhancement of noise control requirements along railways has revealed the inherent limitations of traditional noise barriers, which exhibit diminishing potential for further acoustic performance improvements. Phononic crystals exhibit distinctive band gap properties that enable superior suppression of acoustic waves within their forbidden bands. The application of these materials in rail transit noise control could solve the existing noise mitigation challenges. Moreover, rail transit systems impose stringent installation requirements for ancillary equipment. Consequently, this study develops a novel phononic crystal noise barrier design featuring bi-periodic cross-shaped unit cells, while incorporating the shape characteristics of traditional noise barriers. The effectiveness and applicability of the proposed design have been verified through theoretical and experimental studies.