Cortmech-Damage

• Project management: Andreas Reisinger, Karl Landsteiner University for Health Sciences / Division of Biomechanics
• Project partner(s): Vienna University of Technology / Institute of Lightweight Structures and Structural Biomechanics
• Project duration: 5 months from 1 September 2021

Background

Trabecular bone tissue can be reasonably modelled as an elasto-visco-plastic material. However, load-relief experiments on single trabeculae showed a decrease in elastic modulus with increasing strain. To model this behaviour, the current study aims to scale the elastic component of a previously developed 2-level elasto-visco-plastic rheological model with a plastic strain dependent damage variable (from 0 to 1). This adjustment should allow an improved description of the material properties of bone tissue. Furthermore, new tensile tests will be performed on cortical bone specimens obtained from the shaft of human femurs to compare the use of the proposed model for cortical and trabecular bone tissue. Additional samples will be taken from the femoral neck of healthy and osteoporotic donors to determine if the material properties of the bone tissue change in relation to osteoporosis. In a previous study, it was shown that the material properties of single femoral trabeculae do not change significantly in osteoporosis. The aim of the current study is to investigate whether this also applies to cortical bone tissue in the femoral neck. Knowledge of this information is essential not only for computer simulations, which require reliable material input parameters, but also for a better understanding of the effects of osteoporosis on the material itself.