Analysis of traveling waveform of flexible waveguides containing absorbent material along flanged junctions

摘要

The traveling waveform of a flexible waveguide bounded by elastic plates and with an inserted expansion chamber having flanges at two junctions and a finite elastic membrane atop is investigated through a mode-matching technique. The modeled problem is governed by Helmholtz & rsquo;s equation and includes Dirichlet and higher-order boundary conditions. An acoustically absorbent lining is placed along the inner sides of the flanges at the junctions while their outer sides are kept rigid. Moreover, the edge conditions are imposed to define the physical behavior of the elastic membrane and plates at finite edges. The configuration is excited with the structure as well as fluid-borne modes. The influence of the imposed edge conditions at the connections of the plates and the prescribed incident forcing on the transmission-loss along the duct is elaborated. Specifically, the effects of edge conditions on the transmission-loss of structure-borne vibrations and fluid-borne noise are specified. The performance of low-frequency approximation is compared with that of the benchmark mode-matching method and is found to be in good agreement with relative merits. Apposite numerical simulations are performed to substantiate the validity of the mode-matching technique.(c) 2021 Elsevier B.V. All rights reserved.