Fatigue of self-healing hierarchical soft nanomaterials: The case study of the tendon in sportsmen

: One of the defining properties of biological structural materials is that of self-healing, i.e. the ability to undergo long-term reparation after instantaneous damaging events, but also after microdamage due to repeated load cycling. To correctly model the fatigue life of such materials, self-healing must be included in fracture and fatigue laws and related codes. Here, we adopt a numerical modelization of fatigue cycling of self-healing biological materials based on the Hierarchical Fibre Bundle Model and propose modifications in Griffith’s and Paris’ laws to account for the presence of self-healing. Simulations allow to numerically verify these modified expressions and highlight the effect of the self-healing rate, in particular for collagen-based materials such as human tendons and ligaments. The study highlights the robustness of the self-healing strategy adopted in Nature, and provides the possibility of improving the reliability of predictions on fatigue life in sports medicine