Noise reduction performance of non-uniform resonant cavity periodic array noise barriers

Abstract To address the limitations of traditional sound barriers in controlling low-frequency noise, this study designs a supercell structure comprising five Helmholtz resonator units targeting distinct frequencies, based on the spectral characteristics of highway traffic noise. By periodically arranging these supercell units, the narrow Bragg bandgap limitation inherent in traditional periodic array structures is overcome. The effective coupling of multiple resonant bandgaps with Bragg bandgaps achieves broadband noise reduction in the low-to-medium frequency range. Furthermore, a design strategy involving column-by-column optimization of the sound-absorbing material filling dimensions is proposed. This approach effectively mitigates the attenuation of noise reduction performance in the 500–2000 Hz frequency band caused by acoustic reflection and resonance enhancement effects observed in traditional full (100%) filling. Results indicate that the filling dimensions significantly influence performance within the resonant bandgaps, and the non-uniform filling method extends the effective noise reduction bandwidth to an ultra-wide range of 315 Hz–2500 Hz. Additionally, micro-perforated panels (MPPs) are integrated to encase the internal absorbing materials, thereby enhancing structural durability. Simulation results confirm that the optimized non-uniform resonant cavity periodic array barrier achieves a noise reduction exceeding 10 dB within the characteristic frequency range of highway traffic noise. This study provides a rigorous design framework and new insights for the development of broadband, efficient, and economical periodic array structures.