Orthopaedic Biomechanics

Key Paper Overviews:

Self-tapping ability of carbon fibre reinforced PEEK suture anchors

feerick_2014_screwsAn experimental and computational investigation of the self-tapping ability of carbon fibre reinforced polyetheretherketone (CFR-PEEK) has been conducted. Experimental tests investigated the maximum axial force and torque required for self-taping insertion of each anchor design. Computational simulations reveal significant stress concentrations in the region of the anchor tip, demonstrating that a re-design of the tip geometry should be performed to avoid fracture during self-tapping, as observed in the experimental component of this study. Link to paper

Experimental and numerical characterisation of the elasto-plastic properties of bovine trabecular bone and a trabecular bone analogue

kelly_2011_crushable_foamThe inelastic pressure dependent compressive behaviour of bovine trabecular bone is investigated through experimental and computational analysis. Two loading configurations are implemented, uniaxial and confined compression, providing two distinct loading paths in the von Mises–pressure stress plane. This study provides a novel insight into the pressure dependent yield behaviour of trabecular bone, demonstrating the inadequacy of uniaxial testing alone. The enhanced understanding of the inelastic behaviour of trabecular bone established in this study will allow for more realistic simulation of orthopaedic device implantation and failure. Link to paper

Anisotropic mode-dependent damage of cortical bone using the extended finite element method (XFEM)

Feerick bone xfemAnisotropic damage initiation criteria were developed for extended finite element method (XFEM) prediction of crack initiation and propagation in cortical bone. Four initiation criteria were developed to define crack trajectories relative to osteon orientations and max principal stress for single and mixed mode fracture. Alternate failure strengths for tensile and compressive loading were defined to simulate the asymmetric failure of cortical bone. The unique set of parameters calibrated accurately predicted; (i) the relationship between fracture energy and osteon alignment, and (ii) the alternate crack patterns for both varying osteon orientations and loading angle.  Link to paper