A microstructural model of tendon failure

Collagen fibrils are the most important structural component of tendons. Their crimped structure and parallel arrangement within tendon lead to a distinctive non-linear stress–strain curve when is stretched. Microstructural models can be used relate microscale collagen fibril mechanics macroscale mechanics, allowing us identify mechanisms behind each feature present in curve. Most literature focus on elastic behaviour tendon, there few which model beyond limit without introducing phenomenological parameters. We develop model, built upon recruitment approach, that only contains microstructural split stress into plastic parts, assume yield stretch rupture described by distribution function, rather than being single-valued. By changing shapes distributions their regions overlap, we produce curves generate full range features observed experimentally, including those could not explained using existing models. These include second linear occurring after has yielded, step-like failure peaked. When compare with an find our reduces average root mean squared error from 4.53MPa 2.29MPa, resulting parameter values closer found experimentally. Since parameters have direct physical interpretation, it predict how processes such as ageing, disease, injury affect mechanical tendons, provided quantify effects these microstructure.