Sound Radiation of Locally Resonant Unidirectionally Ribbed Plates

Abstract

This paper suggests a comprehensive case study of acoustic radiation from ribbed plate with inner resonance. Based on explicit design rules and homogenized model for flexural waves, it shows that bending waves propagation significantly differs from classical models in terms of wavenumber features in the neighborhood of local resonances, and comments on the influence of the atypical structural response on the radiated pressure field. The investigation of the acoustic radiation from an infinite and finite ribbed plate is proposed. The trend of the resulting radiated pressure fields from the homogenized model matches with classical models outside frequency bands associated with local resonance, however inner resonance yields additional frequency ranges in which acoustic radiation is either strongly reduced or enhanced. For both mechanical and acoustic responses, theoretical results are successfully compared with finite element method. Further consideration may focus on the radiation mechanisms with coupled bending and torsion in the stiffner.