Optimization of a clamped plate silencer
Theoretical model of sound wave reflection by two cavity-backed plates forming part of the otherwise rigid duct walls.
(Color online) Performance optimization of the clamped plate silencer. (a) Comparison of the performance of the plate silencer (solid curve) with drumlike silencer (dashed curve) with the same cavity geometry of , , and the same mass ratio of . (b) Bandwidth . (c) Dimensionless optimal bending stiffness . (d) Dimensionless lower band limit .
(Color online) Optimization of the nonuniform plate. (a) Optimal distribution of the bending stiffness along the length of the plate. (b) TL. (c) Bandwidth with respect to the relative bending stiffness at the two thin ends. (d) Bandwidth with respect to the length of the thick part of the plate. The cavity geometry is , ; average mass ratio =1.
(Color online) Comparison of the vibration velocity distribution between the clamped nonuniform plate (solid lines) and the simply supported plate (dashed lines). (a) , real parts. (b) , real parts. (c) , imaginary parts. (d) , imaginary parts.
(Color online) Comparison of the clamped nonuniform plate with the simply supported uniform plate (solid lines: nonuniform plate; dashed lines: simply supported). The cavity geometry is , , and the average mass ratio . (1a) TL. (2a) Odd-even modal interference index. (3a) Sound reflected by the even modes. (4a) Sound reflected by the odd modes. The second and third columns compare the modal amplitude,, the modal reflection coefficient,, the single mode reflection,, and the modal contribution of the two plate silencers. The four peak positions are identified in all the subfigures.
The four-microphone, two-load measurement system (dimensions in mm).
Three-point bending test of the balsawood plate. (a) Schematic of the bending test. (b) Load versus extension at the middle point.
(Color online) Comparison of the measured data (with open circles) with theoretical solution (without open circles) for the expansion chamber. (a) TL. (b) The absorption coefficient . (c) The reflection coefficient .
(Color online) Comparison of experimental data (solid curves with open circles) with theoretical solution (solid curves without open circles). (a) TL. (b) The absorption coefficient . (c) The reflection coefficient . The dimensionless bending stiffness , the mass ratio .
(Color online) Modeling of plate damping mechanisms with two set of damping factors. (1a) and (1b), and (1c) show the results with , . (2a), (2b), and (2c) are the results with , .
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