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Abstract
In recent years, the study of trabecular bone has benefited from the development of improved medical imaging, experimental measuring techniques, computational engineering analysis methods and computer hardware. This has been derived by the need to better understand, monitor and treat bone conditions (e.g. osteoporosis) and to improve the design of orthopaedic implants (e.g. artificial hips). The work presented in this thesis combines the above advances into a study of trabecular bone. μCT imaging and nanoindentation provide the raw geometry and material property data, respectively, for the finite element analysis suite FEEBE (Finite Element-By-Element). This suite is designed and validated for small deformation kinematics before being applied to individual trabeculae, cores of trabecular bone and whole bone specimens, for the determination of apparent modulus and tissue level deformations. Results show the importance of incorporating local heterogeneity in tissue level properties, and maintaining in-vivo boundary conditions on the bone when modelled or experimentally tested. A large deformation kinematics module of FEEBE is used to model trabecular bone buckling. Asymmetric micro-damage criteria are added to this module allowing the investigation of including tissue level heterogeneity in bone damage behaviour. A novel element removal scheme is also developed and incorporated, giving new insights into bone micro-fracture. The complete FEEBE suite is used to determine trabecular bone apparent modulus, ultimate strength, ultimate strain, asymmetric tissue damage strains, asymmetric tissue fracture strains, and the accumulation of micro-damage and micro-fracture in a single computational analysis.
