NUMERICAL ANALYSIS OF POROUS SOLIDS

Abstract

The main objective of this project is to study the mechanical behaviour of anisotropic porous solids. The mechanical response of this class of materials depends on porosity, which is a primary factor affecting the mechanical characteristics. The other parameters that are commonly used to describe the orientation of material’s microstructure are known as fabric tensors. Fabric tensors characterize the arrangement of the microstructural components in a porous material. The concept of fabric tensors is employed to define the constitutive equations and the corresponding failure criteria of porous solids. The presence of liquid in a porous solid can influence the mechanical properties. When the material is in compression the deformation process is constrained and the mechanical behaviour is different from that observed in the dry material. This effect has also been investigated. To illustrate the performance of the formulation, a numerical analysis of the fracture in proximal femur due to a sideways fall was performed. The analysis incorporated a finite element model developed in the work of Pietruszczak et al.(1999a), in which the geometry of femur was extracted from CT scans. The numerical study in this project extends the previous work in two major areas. First, a static analysis was performed, taking into the account the biphasic nature of the bone material. The second contribution concerns the extension of the analysis to dynamic range, which simulates more closely the condition of a sideways fall.