Fracture in porous bone analysed with a numerical phase-field dynamical model

A dynamic phase-field fracture finite element model is applied to discretized high-resolution three-dimensional computed tomography images of human trabecular bone to analyse rapid bone fracture. The model is contrasted to quasi-static experimental results and a quasi-static phase-field finite element model. The experiment revealed complex stepwise crack evolution with multiple crack fronts, and crack arrests, as the global tensile displacement load was incrementally increased. The quasi-static phase-field fracture model captures the fractures in the experiment reasonably well, and the dynamic model converges towards the quasi-static model when mechanically loaded at low rates. At higher load rates, i.e., at larger impulses, inertia effects significantly contribute to an increased initial global stiffness, higher peak forces and a larger number of cracks spread over a larger volume. Since the fracture process clearly is different at large impulses compared to small impulses, it is concluded that dynamic fracture models are necessary when simulating rapid bone fracture.

Automated summary

A dynamic phase-field fracture finite element model is used to investigate rapid bone fracture in human trabecular bone based on high-resolution three-dimensional computed tomography images. The model is compared to quasi-static experimental results and a quasi-static phase-field finite element model. The experiment shows complex crack evolution with multiple crack fronts and crack arrests, while the quasi-static phase-field fracture model can reasonably capture the fractures in the experiment. At higher load rates, inertia effects significantly contribute to increased stiffness, higher peak forces, and more cracks spread over a larger volume. The study concludes that dynamic fracture models are necessary for simulating rapid bone fracture.