January 12, 2017
Two multiscale approaches for fracture analysis of full scale femur are developed. The two approaches are the reduced order homogenization (ROH) previously developed by the first author and his associates and a novel accelerated reduced order homogenization (AROH). The AROH is based on utilizing reduced order homogenization calibrated to limited experimental data as a training tool to calibrate a simpler, single-scale anisotropic damage model. For bone tissue orientation, we take advantage of so-called Wolff’s law, which states that bone tissue orientation is well correlated with principal strain direction in a stance position. The meso-phase properties are identified by minimizing error between the overall cortical and trabecular bone properties resulting from the quantitative computer tomography (QCT) scans and those predicted by the two-scale homogenization. The overall elastic and inelastic properties of the cortical and trabecular bone microstructure are derived from bone density that can be estimated from the Hounsfield units (HU) which represent the measured grey levels in the QCT scans. For model validation, we conduct ROH and AROH simulations of full scale finite element model of femur created from the QCT and compare the simulation results with available experimental data.