A simple method to minimize displacement measurement uncertainties using dynamic nanoindentation testing

A new simple indentation method is presented, minimizing strongly the influence of uncertainties linked to the displacement measurement, in the context of homogeneous materials indented by a sharp tip. Based on the determination of the derivative of the contact depth with respect to the indentation depth, this method depends indirectly on the displacement measurement, making the technique less sensible to displacement uncertainties. After being validated on flat samples (fused silica, PMMA), the method was tested on a rough specimen (anodized aluminum, Ra=1.7 µm) and on two heated flat samples (fused silica, PMMA, 60 °C). The mechanical properties determined by this new technique are more precise than properties measured by classical nanoindentation measurement.