Can indentation technique measure unique elastoplastic properties?

Ling LIU, Nagahisa OGASAWARA, Norimasa CHIBA, Xi CHEN*

*Corresponding author for this work

Research output: Journal PublicationsJournal Article (refereed)peer-review

57 Citations (Scopus)


Indentation is widely used to extract material elastoplastic properties from measured force-displacement curves. Many previous studies argued or implied that such a measurement is unique and the whole material stress-strain curve can be measured. Here we show that first, for a given indenter geometry, the indentation test cannot effectively probe material plastic behavior beyond a critical strain, and thus the solution of the reverse analysis of the indentation force-displacement curve is nonunique beyond such a critical strain. Secondly, even within the critical strain, pairs of mystical materials can exist that have essentially identical indentation responses (with differences below the resolution of published indentation techniques) even when the indenter angle is varied over a large range. Thus, fundamental elastoplastic behaviors, such as the yield stress and work hardening properties (functions), cannot be uniquely determined from the force-displacement curves of indentation analyses (including both plural sharp indentation and deep spherical indentation). Explicit algorithms of deriving the mystical materials are established, and we qualitatively correlate the sharp and spherical indentation analyses through the use of critical strain. The theoretical study in this paper addresses important questions of the application range, limitations, and uniqueness of the indentation test, as well as providing useful guidelines to properly use the indentation technique to measure material constitutive properties. © 2009 Materials Research Society.
Original languageEnglish
Pages (from-to)784-800
Number of pages16
JournalJournal of Materials Research
Issue number3
Publication statusPublished - 1 Mar 2009
Externally publishedYes

Bibliographical note

The work is supported in part by National Science Foundation CMMI-0407743 and CMMI-CAREER-0643726, and in part by the Department of Civil Engineering and Engineering Mechanics, Columbia University.


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