The Compelling Case for Indentation as a Functional Exploratory and Characterization Tool
Abstract
The utility of indentation testing for characterizing a wide range of mechanical properties of brittle materials is highlighted in light of recent articles questioning its validity, specifically in relation to the measurement of toughness. Contrary to assertion by some critics, indentation fracture theory is fundamentally founded in Griffith–Irwin fracture mechanics, based on model crack systems evolving within inhomogeneous but well‐documented elastic and elastic–plastic contact stress fields. Notwithstanding some numerical uncertainty in associated stress intensity factor relations, the technique remains an unrivalled quick, convenient and economical means for comparative, site‐specific toughness evaluation. Most importantly, indentation patterns are unique fingerprints of mechanical behavior and thereby afford a powerful functional tool for exploring the richness of material diversity. At the same time, it is cautioned that unconditional usage without due attention to the conformation of the indentation patterns can lead to overstated toughness values. Limitations of an alternative, more engineering approach to fracture evaluation, that of propagating a precrack through a “standard” machined specimen, are also outlined. Misconceptions in the critical literature concerning the fundamental nature of crack equilibrium and stability within contact and other inhomogeneous stress fields are discussed.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jul 30, 2015
- Source ID
- 10.1111/jace.13729
Entities
People
- Antonia Pajares
- Brian R. Lawn
- David B. Marshall
- George M. Pharr
- Ivar E. Reimanis
- Jodie E. Bradby
- Michelle L. Oyen
- Nitin P Padture
- Rajan Tandon
- Robert F. Cook
- Trevor F. Page
Organizations
- Australian National University
- Australian Research Council
- Brown University
- Colorado School of Mines
- Engineering and Physical Sciences Research Council
- National Institute of Standards and Technology
- National Nuclear Security Administration
- National Science Foundation
- Newcastle University
- Oak Ridge National Laboratory
- Office of Naval Research
- United States Department of Energy
- University of Cambridge
- University of Extremadura
- University of Tennessee