Exploring the hierarchical structure of lamellar bone and its impact on fracture behaviour: A computational study using a phase field damage model

J Mech Behav Biomed Mater. 2024 Feb 27;153:106471. doi: 10.1016/j.jmbbm.2024.106471. Online ahead of print.ABSTRACTBone is a naturally occurring composite material composed of a stiff mineral phase and a compliant organic matrix of collagen and non-collagenous proteins (NCP). While diverse mineral morphologies such as platelets and grains have been documented, the precise role of individual constituents, and their morphology, remains poorly understood. To understand the role of constituent morphology on the fracture behaviour of lamellar bone, a damage based representative volume element (RVE) was developed, which considered various mineral morphologies and mineralised collagen fibril (MCF) configurations. This model framework incorporated a novel phase-field damage model to predict the onset and evolution of damage at mineral-mineral and mineral-MCF interfaces. It was found that platelet-based mineral morphologies had superior mechanical performance over their granular counterparts, owing to their higher load-bearing capacity, resulting from a higher aspect ratio. It was also found that MCFs had a remarkable capacity for energy dissipation under axial loading, with these fibrillar structures acting as barriers to crack propagation, thereby enhancing overall elongation and toughness. Interestingly, the presence of extrafibrillar platelet-based minerals also provided an additional toughening through a similar mechanism, whereby these structures also inhibited crack propagation...
Source: Journal of the Mechanical Behavior of Biomedical Materials - Category: Materials Science Authors: Source Type: research