Viscoelasticity and Failure of Collagen Nanofibrils: 3D Coarse-Grained Simulation Studies

In this manuscript, we investigate the influence of loading rate and fibril length on viscoelastic and failure behavior of collagen nanofibrils. The computational experiments were performed using three-dimensional shape-based Coarse-Grained models of collagen nanofibrils, with parameters derived from atomistic simulations. The atomistic computational tensile and shear experiments were performed using Molecular Dynamics and extended AMBER force field for aqueous and non-aqueous environments. The Coarse-Grained interactions were defined by both intermolecular and intramolecular potentials which describe non-bonded and bonded interactions respectively. Computational studies revealed that the hydrogen bond network impacts both viscoelastic behavior and failure of collagen nanofibrils. Greater fibril length results in brittle cracking while higher loading rates result in ductile behavior, due to the unwinding and sliding of the fibril. The proposed Coarse-Grained model can be used in further studies incorporating the effects of ageing, such as collagen degradation and glycation.