Investigating the effect of micro-structure on the deformation of saturated fibrous media using direct numerical simulations

- Validation of LB-FE method to model the deformation of saturated fibrous media.
- Development of bulk modulus expression for orthogonal arrangment of cylinders.
- Staggered orthogonal cylinders represent real fibrous medium under compression.
- Bulk modulus of fibrous medium depends on the porosity and not on the fiber diameter.

To understand the effect of micro-structure on the deformation of saturated fibrous media, this study investigates the viability of representing real layered fibrous media through model geometry made of cylinders in orthogonal arrangements. Direct numerical simulations of compression performed on such model geometries, using a coupled lattice Boltzmann and finite element method, facilitate the investigation of micro-structure effect on deformation.The deformational response of the model cylindrical arrangements representing porous media is validated with an existing analytical solution and in doing so the bulk elastic modulus of such an arrangement is evaluated. Based on the critical parameters porosity, permeability and compressive modulus, it is found that cylinders in staggered orthogonal arrangement behave as real layered fibrous porous media during saturated compression. Furthermore an analytical expression is developed to predict the compressive modulus of orthogonal arrangement of cylinders. The expression shows that fiber diameter does not affect the compression of such fibrous media which only depend on void fraction. This is further confirmed through direct numerical simulations.