Nanoindentation of Soft Polymers: Modeling, Experiments and Parameter Identification

Abstract

Since the nanoindentation technique is able to measure the mechanical properties of extremely thin layers andsmall volumes with a high resolution, it also became one of the most important testing techniques for thin polymerlayers and coatings. This work is focusing on the characterization of polymers using nanoindentation, which isdealt with by means of numerical computation, experiments and parameter identification. An analysis procedureis developed using the FEM based inverse method to evaluate the hyperelasticity and time-dependent properties.This procedure is firstly verified with a parameter re-identification concept. An important issue in this publicationis to take into account the error contributions in real nanoindentation experiments. Therefore, the effects of surface roughness, adhesion force and the real shape of the tip are involved in the numerical model to minimize thesystematic error between the experimental responses and the numerical predictions. The effects are quantified asfunctions or models with corresponding parameters to be identified.