A STAGGERED-ARRAY MODEL FOR MINERALIZED COLLAGEN FIBRIL WITH FINITE ELEMENT APPROACH

To investigate the failure mode of the MCFs, it is important to understand how intrinsic residual stress contributes to loading. In this study, first, the analytical Fratzl-Weinkamer model is reproduced and extended with finite element model to examine how compressive residual stresses in mineral platelets influence stress distributions and tensile strength. The results demonstrated that the distribution of residual stress plays a critical role in peak tensile stress and failure initiation in mineral platelets.A non-linear finite element representation is then introduced to incorporate interfaces and crosslinks and enable additional failure mode analysis. It is revealed that compressible residual stresses delay mineral fracture, increase apparent tensile strength, and may induce a brittle-to-ductile transition by shifting mineral fracture to interface sliding. However, increasing crosslink density constrains the sliding, leading to higher stiffness but more brittle behavior.Overall, this research seeks to analyze the mechanical response of MCFs under the influence of residual stress, interface behavior, and collagen crosslinks with finite element models. The results provide insight into explaining experimentally observed changes in bone stiffness and strength associated with mineralization, hydration, and aging.