NUMERICAL INVESTIGATION OF MICROSTRUCTURE EFFECT ON ACOUSTIC PROPERTIES OF UNDERWATER ANECHOIC COATINGS

Abstract

This paper presents a simulation-based model for predicting the acoustic properties of underwater anechoic structures with its main layer made of viscoelastic sound absorbing materials including air-filled cavities. Some preliminary numerical results are first compared with the published analytical and experimental data to validate the proposed modeling. Then, a developed design of anechoic using two arrays of air-filled bubbles is considered. It is observed from the investigation results that the new coating shows an interesting sound absorbing performance (i.e., absorbing > 80% incident energy in a large frequency range 25 MHz) compared with the original one having a single air cavity array. The developed structure allows broadening and tailoring their acoustic performance (peak frequency and averaging level) by tuning some microstructural parameters of the air-filled cavity (shape and size) and its distribution (location and fraction).