Implementing a Microstructure-Enhanced Material Model using Ansys USERMAT for the Prediction of Bone Failure
Continuum FE models of bones and bone-implant configurations have become a standard tool to estimate bone strength. These models are usually based on clinical CT scans.
In virtually all of these models, material properties assigned to the bone elements are chosen as isotropic with a stiffness based only on the density distribution. It has been shown, however, that trabecular bone can be highly anisotropic and it shows elastic plastic damage mechanical behaviour with softening.
In this study, a new database method was used to estimate anisotropy from clinical CT images. Finally, an anisotropic-elastic plastic damage model was implemented in ANSYS to simulate failure and post failure behavior of femurs during a fall to the side condition.