Waveguide absorbers based on spiral acoustic black holes for damping vibration in a plate structure

Abstract

We propose a waveguide absorber (WGA) based on a spiral acoustic black hole (ABH) to reduce vibration in plates. The geometrical dimensions of the WGA are determined so that it has a lower cut-on frequency than a target frequency by using the impedance method. We also determine the attachment location and direction of the WGA on a plate to maximize its damping performance based on the structural intensity analysis. A couple of WGAs attached to a plate could reduce the mobility of the plate by more than 10 dB. In addition, the WGAs had far less weight but could achieve larger peak reductions compared to thick damping material or spiral ABHs attached to edges.