Fracture processes in cortical bone: effect of microstructure

Understanding of bone fracture can improve medical and surgical procedures. Therefore, investigation of the effect of bone’s microstructure and properties as well as loading conditions on crack initiation and propagation is of great importance. In this paper, several modelling approaches are used to study fracture of cortical bone tissue at various length scales and different types of loading. Two major problems are tackled: crack propagation under impact loading and bone cutting in surgical procedures. In the former case, a micro-scale finite-element (FE) fracture model was suggested, accounting for bone’s microstructure and using X-FEM for crack-propagation analysis [1, 2]. The cortical bone tissue was modelled as four-component heterogeneous materials. The morphology of a transverse-radial cross section captured with optical microscopy was used to generate FE models; extensive experimental studies provided necessary mechanical input data [3]. The problem of bone cutting was treated within the framework of tool-bone interaction analysis [4, 5]. A two-domain approach was used, with a process zone simulated using a smooth-particle hydrodynamics method. This zone was embedded in a continuum domain with macroscopic anisotropic properties obtained in experiments. This study is supported by analysis of damage induced by interaction between the cutting tool and the bone tissue using wedge-indentation tests and considering also the anisotropic behaviour of the bone.