Abstract Noise control remains a critical challenge in mechanical engineering, particularly for low- and mid-frequency noise mitigation in industrial applications. This study proposes a composite structure combining micro-perforated panels (MPPs) and back-shaped cavities, targeting the 20–1000 Hz frequency range. An acoustic-electrical analogy model is developed to characterize the sound absorption mechanism. A carefully selected set of parameters is then utilized to fabricate a prototype, which undergoes rigorous experimental validation. Additionally, the finite element method is employed in conjunction with the control variable approach in tandem to systematically investigate the impact of eight structural parameters on the sound absorption performance of the composite structure. Following this, Particle Swarm Optimization (PSO) is employed to optimize the structural parameters. The results indicate that among the eight geometrical parameters, the perforation rate and the second layer’s cavity depth significantly affect the acoustic performance, while the remaining parameters exhibit minimal or negligible impact. The optimized composite structure demonstrates remarkable efficacy in mitigating low-frequency and mid-frequency noise, effectively broadening the acoustic bandwidth from 165 Hz to 740 Hz within these frequency ranges. The research conducted in this study provides valuable insights and serves as a reference for noise reduction in practical machinery equipment and indoor acoustic environments.
Zhou et al. (Thu,) studied this question.