Modelling of crack propagation in heterogeneous materials like bones

Fractures of the metacarpal condyle are a common orthopaedic injury in Thoroughbred racehorses. A large proportion of injuries occur in the absence of a specific traumatic event and show typical characteristics of stress fractures. The purpose of this work is to develop a combined remodelling and fracture finite element based framework allowing for integrated simulation of equine 3rd metacarpal remodelling under specific exercise regime (boundary conditions), followed by crack propagation analysis. Such an approach may help to better understand the correlation between high exercise intensity, bone adaptation and fracture risk, ultimately improving the welfare of the racehorse. The authors' bone remodelling model provides the prediction of bone material distribution. Assessment of the fracture risk is conducted by evaluating the strain release energy rate within the context of configurational mechanics. The implemented framework provides a robust, accurate and energy consistent method for quantifying the influence of bone adaptation on the fracture propensity. Performance of the presented method is demonstrated by the numerical example of crack propagation in a heterogeneous plate in 3D. The proposed approach is fully implemented in open-source finite element library MoFEM. The promising results of this study offer a~novel framework to simulate crack propagation in bones, followed by bone adaptation, potentially providing better insight into quantifying propensity for fracture