Investigation and modelling of damping in a plate with a bonded porous layer

Abstract

SUMMARYBehavior of a poroelastic material bonded onto a vibrating plate is investigated in the low frequency range. From the analysis of dissipation mechanisms, a model accounting for damping added by the porous layer on the plate is derived. This analysis is based on a 3-D finite element formulation including poroelastic elements based on Biot displacement theory. First, dissipated powers related to thermal, viscous and viscoelastic dissipation are explicited. Then a generic configuration (simply supported aluminium plate with a bonded porous layer and mechanical excitation) is studied. Thermal dissipation is found negligible. Viscous dissipation can be optimized as a function of air flow resistivity. It can be the major phenomenon within soft materials, but for most foams viscoelastic dissipation is dominant. Consequently an equivalent plate model is proposed. It includes shear in the porous layer and only viscoelasticity of the skeleton. Excellent agreement is found with the full numerical model.

A new analytical model for vibration of a cylindrical shell and cardboard liner with focus on interfacial distributed damping

“…Furthermore, these methods are often applied only to beams and plates [12][13][14][15][16] (rather than cylindrical shells), systems with only proportional damping [17], or cited in patents [18][19] with little scientific justification. In most publications, the primary damping mechanism is material (structural) damping, whereas for a cardboard liner, significant damping may arise due to friction at the sliding interface.…”

Nonlinear damping of a plate using Faraday instability of a fluid film

“…Nevertheless, note that the damping added by the fluid film is comparable to thoses obtained with viscoelastic or porous material treatments [1,6].…”

“…These techniques are limited by viscoelastic properties that depend on frequency and temperature [3]. Designed primarily for sound absorbing, porous materials such as polymer foam may also add significant damping when mounted onto a structure [4][5][6]. To improve the efficiency of Fig.…”

Numerical investigation of active porous composites with enhanced acoustic absorption

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