Abstract Scope |
Nanoindentation offers a unique but challenging opportunity to probe the mechanical properties of micron-scale features in hard biological tissues like wood and bone. However, traditional nanoindentation methods were developed for hard, inorganic materials. These traditional methods also tacitly assume specimens are rigidly supported, homogeneous, and semi-infinite. These assumptions are violated in biological materials. This paper presents improved nanoindentation methods, including experimental protocols and an analysis algorithm, specifically designed to improve the accuracy of Berkovich nanoindentation measurements in complex biological tissues. The improved methods are built off the traditional methods. But the key is to assess mechanical properties as a function of size in each nanoindentation location. This size-dependent data is used in the analysis algorithm to correct the data for structural compliances arising from nearby edges and specimen-scale flexing, as well as to detect potential errors caused by issues like surface detection errors, displacement drift, surface tilt, and dirty probes. |