On the contact law within a poroelastic granular material
Résumé
Poroelastic materials are widely used for acoustic treatments due to their efficient sound absorption. Granular materials present also interesting properties according to wave propagation and attenuation. In this work, we study the properties of poroelastic spheres made of polymer foam. The objective is to determine the contact stiffness between a poroelastic sphere and a rigid plane, with a view to homogenize a poroelastic granular material for sound propagation. First, we present experimental results obtained with poroelastic half-spheres, made of same materials but different radii, subjected to a quasistatic strain by a rigid plane. The results show two regimes: a nonlinear Hertzian regime at high strain, which is radius-dependent, preceded by a regime common to all samples at low strain, which relies on the features of the surface. The limit between the two regimes is further studied by a numerical approach using a finite element model of a representative volume. The poroelastic grain is modeled by Kelvin cells within Abaqus software and takes into account the geometrical non-linearity during the deformation.
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