BIOMED Seminars: Mechanics of Cortical Bone at Multi-Length-scale
Prof. Ahmad R. Najafi will give a presentation at the BIOMED Seminars in the School of Biomedical Engineering, Science, and Health Systems at the Drexel on Wednesday, October 11, 2017.
Title:
Mechanics of Cortical Bone at Multi-Length-scale
Abstract:
Bone tissue has an intricate arrangement of material structures at multiple length scales which work in harmony to perform a variety of mechanical, biological and chemical functions. The hierarchical structure of bone, spanning from the nanoscale, sub-microscale, microscale, mesoscale to the macroscale, significantly contributes to high stiffness, strength, toughness, and energy absorption, light weight and other remarkable mechanical properties of bone. In this seminar, we present our results on the multiscale characterization and modeling of bone which provide structure-composition-properties relations. To characterize the bone structure and composition, we use micro-computed tomography, transmission electron microscopy, ash and water contents, whereas we implement nanoindentation, microindentation (reference point indentation) and other traditional mechanical tests such as fracture test to measure mechanical properties of bone. The outcomes of our experimental studies are used as inputs for our numerical and analytical models as well as the validation of modeling results. Our finite element and analytical model investigates the cortical bone fracture at the microscale level. The results indicate that cortical bone microcrack propagation is greatly influenced by osteonal density and bone microstructural heterogeneity, suggesting bone resistance to fracture can be predicted, at least in part, by quantification of osteonal density and bone material mismatch. Modelling of bone, accounting for different scales in a conjunction with experimental works, provides new and needed insights into the fracture and strength of bone, which, in turn, can lead to improved diagnostic tools and drugs for the treatment of bone diseases such as osteoporosis.