Cortical bone fracture analysis including the combined influence of osteon orientations, applied load and crack lengths: A numerical investigation.

Similar to how fiber orientation affects composite materials, osteon orientation affects the elasticity and fracture behavior of cortical bone. The objective of this work is to predict the combined effect of orientations of the osteon, applied load, and various crack lengths on the fracture characteristics of cortical bone. Orthotropic modeling and analyses of cortical bone were carried out using the linear-elastic fracture mechanics (LEFM) based extended finite element method (XFEM). Five values of applied mode-I and mode-II load, five distinct crack lengths, and seven angular osteon orientations were taken into consideration to predict the change in SIF. In this work, the 2-D plane stress assumption with a straight-edge crack was taken into consideration. It was found that the values of SIF significantly increased when the load (15-35 MPa) and fracture length (1.8-2.2 mm) increased. SIF (K_I) values under mode-I loading were discovered to be substantially lower than SIF (K_I and K_II) values under mode-II loading. Results of this study showed that osteon orientations with different crack lengths and applied loads had a significant impact on cortical bone fracture characteristics. Only the crack's opening was discovered to be caused by mode-I loading; however, both the opening and shearing of the crack were found to be caused by mode-II loading. Despite differences in applied loads, crack lengths, and osteon orientations, the values of the SIF predicted in this work (under mode-I loading) using LEFM-based XFEM exhibited good agreement with the prior published experimental and numerical data.