On Correlating Elastic Properties of the Porous Structure to Pore Attributes

The correlation between the stiffness and porosity of the porous material is studied for many decades. In most cases the goal was to propose an equation correlating the fractional change in elastic modulus to the net porosity for a given pore geometry (often spherical). The mechanical behavior of the porous material is often assumed to be isotropic with few exceptions where the directionality is addressed. In the current study through numerical analysis in Ansys APDL it is shown that the variation of elastic modulus with net porosity is also affected by the factors like shape, size, slenderness and relative orientation of the pores. In addition a general equation is proposed to represent the effect of net porosity and aspect ratio on the variation of Young's moduli in different directions. The behavior of the porous structure is found to be neither isotropic nor completely anisotropic. If the solid phase is isotropic, then the behavior of the porous structure is best classified as orthotropic.