Sound transmission characteristics of underwater flexible micro-perforated panels

It is unlikely to ignore the coupling effect between the structure of the micro-perforated panel (MPP) and the water medium during the application of MPP in the water medium. Theoretical and experimental studies on the sound transmission characteristics of multi-layer flexible micro-perforated panels (FMPPs) under normal incidence conditions were performed. The transfer impedance of finite-sized FMPPs was calculated with the modal superposition method, and the transmission and energy dissipation factor of the FMPPs was derived using the transfer matrix method. Besides, the studies on the effect of panel elastic properties and the arrangement order on the sound insulation performance were carried out. The sound transmission loss (STL) curve remains unchanged when the arrangement order was transposed symmetrically, and it was beneficial to improve the energy dissipation factor when the perforation rate decreased from the sound source side. Theoretical results were verified on a water-filled impedance tube using the two source-location methods. (C) 2021 Elsevier Ltd. All rights reserved.