Multiscale Experimental and Computational Investigation of Cortical Bone Fracture

Previous experimental studies of cortical bone have investigated cortical bone fracture toughness and crack trajectory as a function of microstructural alignment of osteons [1,2]. The dependence of osteon orientation on screw pullout force and crack propagation trajectory during screw pullout has been demonstrated previously by Feerick and McGarry (2012) [3]. The alternate failure modes for longitudinal and transverse screw pullout observed in the latter study are shown in Figure 1. Using an isotropic damage criterion with crack growth was simulated using an element deletion technique. An explicit representation of cortical bone microstructure was required to replicate experimental observations. The use of such a computational scheme for 3D macro-scale applications is not viable given the requirement of explicit representation of the microstructure. Other computational studies of cortical bone have also developed geometric representations of the microstructure of cortical bone to simulate the fracture and establish crack trajectories [4]. Again, upscaling these detailed microstructural geometries in 3D macroscale simulations of fracture would currently be computationally unfeasible.