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Shafts used in torque and angular velocity transmission may behave as torsional vibration amplifiers due to resonance followed by unwanted vibrations. Many technologies are applied to attenuate vibration in certain frequency ranges in automotive, aerospace and industrial applications. More recently, using the concept of periodic structures (phononic crystals and metamaterials), it has been shown to be possible to obtain frequency band gaps where elastic waves cannot propagate and, therefore, standing waves cannot build up, thus avoiding resonance. Using a few periodic cells large attenuation can be obtained, so that the structure behaves like a mechanical filter. Investigations in periodic structure dynamics have been developed in recent years aiming at to attenuating specific and wide frequency ranges. The periodic structure can be a combination of different materials, or a unique material varying the geometry periodically.

Poroelastic materials are commonly used in passive noise control due to their low cost and relative efficient acoustic absorption characteristics in the middle to high frequency range. They are constituted by a rigid and a fluid phase responsible for the dissipation mechanisms attenuating the propagation of acoustic waves inside the material. The understanding of these phenomena and their translation into parameters existing in the mathematical formulations for poroelastic materials are of paramount importance in the design of optimized structures for choosing the proper materials for each application. This work presents studies on the validation of a melamine foam characteristics using the equivalent fluid model from Johnson-Champoux-Allard (JCA) and a rigid structure.