A Spherically Anisotropic Microstructure Model for Fluid-saturated Poroelastic Isotropic Materials

The microstructure model proposed in this work is an assemblage of hollow spheres saturated by a fluid. The solid phase of each sphere is linearly elastic and spherically anisotropic. On the basis of this microstructure model, the effective bulk modulus, Biot’s coefficient and porosity variation are determined. It is shown that local anisotropy has important effects on the macroscopic isotropic poroelastic properties via a dimensionless material parameter which characterizes the degree of anisotropy and exponentially affects the porosity.