Acoustic mechanism of the vertical incidence and diffusion domain of the front protective wall containing microfibers-HT400P (Retracted article. See vol. 192, 2022)

Based on wave theory, the propagation equations of sound waves in single layer and multilayer media are established. In the traditional multi-layered structure and the microfiber multi-layered structure, the sound transmission characteristics of air in the middle and the back are analyzed by numerical simulation and acoustic parameter experiment. The effects of bending, viscous characteristic length and thermal characteristic length on the acoustic performance of multilayer structures are compared. At the same time, the sound transmission characteristics of two multilayer structures are compared and analyzed. The results show that the sound insulation performance of the multi-layer structure increases when the air sandwich appears in the middle of the composite structure. The sound insulation performance of the single composite structure, the sound insulation performance of the double wall structure and the superfine fiber structure are better than the traditional PU (Polyurethane, PU) foam and EVA (Ethylene vinyl acetate copolymer, EVA) composite structure. (C) 2021 Elsevier Ltd. All rights reserved.