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Load-Displacement Behavior During Sharp Indentation of Viscous-Elastic-Plastic Materials

Published online by Cambridge University Press:  17 March 2011

Michelle Oyen-Tiesma ,
Yvete A. Toivola  and
Robert F. Cook
Michelle Oyen-Tiesma
Affiliation:
Department of Chemical Engineering and Materials Science, University of Minnesota Minneapolis, MN 55455
Yvete A. Toivola
Affiliation:
Department of Chemical Engineering and Materials Science, University of Minnesota Minneapolis, MN 55455
Robert F. Cook
Affiliation:
Department of Chemical Engineering and Materials Science, University of Minnesota Minneapolis, MN 55455
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Abstract

A constitutive equation is developed for geometrically-similar sharp indentation of a material capable of elastic, viscous, and plastic deformation. The equation is based on a series of elements consisting of a quadratic (reversible) spring, a quadratic (time-dependent, reversible) dashpot, and a quadratic (time-independent, irreversible) slider—essentially modifying a model for an elastic-perfectly plastic material by incorporating a creeping component. Load-displacement solutions to the constitutive equation are obtained for load-controlled indentation during constant loading-rate testing. A characteristic of the responses is the appearance of a forward-displacing “nose” during unloading of load-controlled systems (e.g., magnetic-coil-driven “nanoindentation” systems). Even in the absence of this nose, and the associated initial negative unloading tangent, load-displacement traces (and hence inferred modulus and hardness values) are significantly perturbed on the addition of the viscous component. The viscous-elastic-plastic (VEP) model shows promise for obtaining material properties (elastic modulus, hardness, time-dependence) of time-dependent materials during indentation experiments.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 649: Symposium Q – Fundamentals of Nanoindentation & Nanotribology II , 2000 , Q1.5
Copyright
Copyright © Materials Research Society 2001

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References

REFERENCES

1. Oliver, W.C. and Pharr, G.M., J Mater Res 7, 1564 (1992).Google Scholar
2. Briscoe, B.J., Fiori, L., and Pelillo, E., J Phys D: Appl. Phys. 31, 2395 (1998).Google Scholar
3. Cook, R.F. and Pharr, G.M., J. Hard Mater. 5, 179 (1994).Google Scholar
4. Adhihetty, I., Hay, J., Chen, W., and Padmanabhan, P., Mat. Res Soc. Symp. Proc 522, 317 (1998).Google Scholar