Complex Network Analysis of Bone for Understanding Multiscale Mechanisms of Strength

Bone is a complex, heterogeneous material that displays mechanisms of fracture resistance across multiple scales. At the mesoscale, trabecular (cancellous) bone is a strong, lightweight tissue consisting of interconnected bone struts (trabeculae) that erode with age and disease, resulting in increased fracture propensity. Due to its structural resemblance to a network, we use micro-computed-tomography images to model trabecular bone as weighted networks, and we compare network metrics with mechanical response in order to investigate how its architecture gives rise to fragilities or conversely robustness to fracture. This approach also allows us to use dynamic community detection to identify pathways for force propagation. We simulate damage with finite element analysis on beam-element structures that correspond to 3-D realizations of the network models, but are less computationally intensive than continuum-element reconstructions of bone, and we validate our results against the continuum models. Our results can be integrated into a comprehensive, multiscale characterization of bone, and our approach can be applied to the analysis of other hierarchical materials.