In previous studies, theories have been developed and simulations performed to show that properly designed fibrous media can be very effective at reducing structural vibration as well as absorbing airborne sound. Therefore, the potential range of noise control applications for fibrous media such as glass and polymeric fiber has been broadened due to this multi-functionality. Since the acoustical, sound absorption properties of these two kinds of fibers are well-known, the current study focused on a comparison of their damping performance when they are used as layered dampers for a fuselage-like structure: i.e., a panel with frames. A layer of each kind of fiber was modeled as resting on the stiffened panel, which was then driven by a convective pressure. The solution for the panel motion was first found in the wavenumber/frequency domain, and an inverse transform was then applied to obtain the spatial results. Through model calculations, the structural damping characteristics of these two fibrous dampers were analyzed and quantified in terms of an equivalent loss factor. In addition, microstructures were designed for each fiber type that results in optimal damping performance over a frequency range of interest. Guidelines were also established for the effective use of these media in structural damping applications.
Structural damping, Fibrous media, Numerical modeling, Acoustical materials
Acoustics and Noise Control
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