Toward Material Property Extraction from Dynamic Spherical Indentation Experiments

Author(s):

John D Clayton, Daniel T Casem, Jeffrey T Lloyd, and Emily H Retzlaff

Abstract:

A new treatment of dynamic indentation using dimensional analysis is forwarded, and a general framework for extraction of material property information (i.e., constitutive model parameters) from spherical indentation experiments is set forth. Static indentation is reviewed as a prerequisite to dynamic indentation, since the former is a subset of the latter with inertia, rate dependence, and adiabatic heating removed. Experimental data obtained from instrumented spherical indentation in a miniature Kolsky bar apparatus are evaluated via the proposed method of dimensional analysis. The substrate material is aluminum alloy Al6061-T6. Several definitions of indentation strain proposed for static indentation are newly assessed for dynamic indentation, as are indentation strain rates. The analysis suggests that while fidelity of the experimental method and inertial effects could inhibit extraction of elastic properties, extraction of certain plastic constitutive properties is feasible. However, current data are insufficient to enable determination of a complete and unique set of all physical properties. Motivated by the current results, new experiments and simulations are proposed that would enable identification of influential properties, facilitating inverse analysis.