Experimental assessment of permeability variation with the compression of soft reticulated foams

Abstract

The resistance to flow of imbibed fluids in soft porous structures subjected to compression can be a solution for impact attenuation. The mechanism, named ex-poro-hydrodynamic (XPHD) lubrication, is based on permeability variation with porosity, which, at its turn, depends on the compression degree of the porous structure. A literature survey revealed scarce information regarding the permeability of compressed reticulated foams or 3D fiber-based structures, used in XPHD applications. Moreover, the permeability depends on the fluid and its velocity. This paper presents experimental data of the permeability of glycerine for an in-plane, axisymmetric flow through a porous material subjected to various degrees of compression. The experiments were done on an in-house made radial permeameter with pressure differentials up to 6 bars. The experimental data was compared with the predicted results, using the well-known Kozeny-Carman equation and related formulations.

Mechanical and structural characterisation of a 3D warp-knitted spacer fabric subjected to compression

“…In the last decades, theoretical ( [11], [12]) and experimental results ( [13], [14]), have shown that using porous and deformable materials, imbibed with fluids, greatly increases their impact damping capacity making the evaluation process of the material's permeability variation with compression level an activity of great importance. The evaluation of this variation has been possible with the use of complex experimental devices [15] and has proved to be an useful and thorough approach, but also time and resource consuming.…”