Bone is a complex natural composite with a lamellar structure on the micro scale. In this study, scanning nanoindentation was used to assess the mechanical properties of individual lamellar and inter-lamellar components of trabecular bone under static and dynamic loading conditions. The combination of careful sample preparation, good topographical characterization of the sample surface, and a scanning nanoindenter provided insight into the mechanical properties of the individual lamellar structures. The results of quasi-static, as well as dynamic nanoindentation tests of bone are reported and discussed.
A surface roughness of only 18-20 nm RMS was achieved. Nonetheless, indentation depths in the range of 100 nm and above were required in order to minimize the effect of topography on the measurement. This requirement conflicts with the need to keep the probed volume small enough to sample only one component at a time. A simple volume-averaging model was developed and used as a tool to determine when individual lamellar bone structures were being probed and to help determine the properties of the lamellar and inter-lamellar materials.