Estimation of Validity for the Trabecular Bone Indentation by FEA

Phak, Kunil; Lee, Moon Kyu; Choi, Kuiwon; Lee, Tae Soo

Abstract

Mechanical properties of trabecular bone were major particulars to understand a bone's quality and a information of osteoporotic patients. In a measurement of trabecular bone's properties, however, it was very difficult to extract and prepare it's specimen. Thus the goal of this study was to estimate the validity for indentation test which widely used as a non-destructive test of porous materials such as a trabecular bone using a FE analysis. We composed the FE model based on uniaxial compression test and clinical observation. It was able to extend for the simulation of indentation test. In addition to that, this FE model well imitated a behavior of a trabecular bone. We obtained a load-displacement curve by the indentation simulation and calculated the elastic modulus using Pharr's hypothesis. We estimated the validity of the indentation test by comparing compression simulation and indentation simulation. When indenter diameter was five times of pore size, the result of indentation simulation converged on compression simulation. If indentation depth was insufficient, the result of indentation simulation made serious errors. Therefore, to obtain the appropriate result of the indentation test, indenter diameter have to be five times of pore size and indentation depth should be about 8% of indenter diameter at least.