Mechanisms Governing the Inelastic Deformation of Cortical Bone

摘要

To understand the inelastic response of bone, a two-part investigation has been conducted. In the first, a flexural test protocol has been designed and implemented that monitors the axial and transverse strains on both the tensile and compressive surfaces of cortical bone. The results are used to assess the relative contributions of dilatation and shear to the inelastic deformation. Unload/reload tests have characterized the hysteresis and provided insight about the mechanisms causing the strain. These tests reveal strain healing attributed to sacrificial bonds. The second part devises a model for the stress/strain response, based on a recent assessment of the nano-scale organization of the collagen fibrils and mineral platelets. The model rationalizes the inelastic deformation in tension, as well as the permanent strain and hysteresis.