Composite honeycomb metasurface panel for broadband sound absorption.

Composite honeycomb sandwich panels have been adopted in a wide range of applications owing to their excellent mechanical properties. This paper demonstrates a design of a composite honeycomb metasurface panel that can achieve 90% sound absorption from 600 to 1000 Hz with a thickness less than 30 mm. The panel is comprised of periodically and horizontally arranged honeycomb "supercells" which consist of unit cells of different geometric parameters (pore size). Two different analytical models (Helmholtz resonator model and micro-perforated panel model) are used to calculate the sound absorption of the panel, and they are further validated by a numerical model. The relatively broadband sound absorption is found to be attributed to the coupling between unit cells, which is illustrated by both the complex frequency plane theory and the calculated sound intensity field.