Importance of geometric parameters in modeling of porous materials - a finite element study

Abstract

Porous materials consist of interconnected skeletal structure around a porous space. The skeletal structure is usually formed of a solid phase and the pores are typically filled with a fluid (liquid or gas). Porous materials are characterized by two essential geometric properties: porosity and pore size distribution (PSD), which influence their bulk mechanical properties. Porosity, which is defined in terms of the ratio between the envelope and the skeletal densities, is sufficient to describe the elastic bulk properties of porous materials. Gibson and Ashby developed a power scaling law expressing the linear relation between the elastic modulus and the relative density. The PSD describes the spatial variation of the pore sizes and has recently been shown to influence the mechanical properties of porous materials. In addition to porosity and PSD, the pore characteristics, namely pore size and shape, and pore-wall size and shape, also determine the geometric properties that influence the bulk response of these materials. In this study, the importance of the above-mentioned geometric parameters in the modeling of the porous materials is studied using a computational framework. The bulk mechanical response under large deformation of various porous structures with PSD based on different probability density functions (PDF) and different combinations of other geometric properties under uniaxial compression is investigated. The sensitivity of mechanical response to these geometric parameters is studied. Interdependent parameters which are significantly influential are identified. By controlling these parameters, the synthesis of porous materials can be guided and optimized.