Evaluation of the acoustic radiation of contrasted orthogonally stiffened plates from homogenized model

This paper presents a study of the acoustic radiation from a ribbed plate with inner resonance. Based on explicit design rules and homogenized model for flexural waves, it reminds that bending wave propagation significantly differs from classical models in case of strong contrast between constituents, resulting into inner resonance. In order to demonstrate that this model advantageously supplements the Timoshenko orthotropic plate model, it links the atypical structural response on common vibroacoustic indicators, which are of value to discuss on different levels of abstraction. In either infinite or finite cases, the resulting indicators obtained from the homogenized model matches with classical trends 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 quantities, key indicators are successfully compared with classical theory for either poorly and highly contrasted ribbed plates in order to confirm the diversification of acoustic behaviors encompassed by the homogenized model.