Structural damping by lightweight poro-elastic media

The structural damping performance of limp porous media: i.e., fibrous layers with negligible bulk frame elasticity, was investigated previously. Presented here is a study focusing on porous damping media (i.e., fibers, foams, etc.) with elastic frames, here referred to as "poro-elastic media". By using the near-field damping (NFD) analytical toolbox, the power distributions and damping performances were evaluated for both a limp porous layer and a poro-elastic layer resting on an infinitely-extended stiff panel driven by a harmonic line force. The elastic layer was found to outperform the limp layer due to the additional structural dissipation within the solid phase of the material. The effect of bonding a poro-elastic layer to the unconstrained panel was also studied. The panel was then made partially-constrained by adding two discontinuities with finite translational and rotational inertias. The constrained panel case was validated by comparison with a finite element model, and was also used to compare the damping loss factors of a limp porous layer and a poro-elastic layer. Insights and concepts are summarized for the design of a poro-elastic structural damper. (C) 2019 Elsevier Ltd. All rights reserved.