Spherical indentation of porous ceramics: cracking and toughness
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Accepted version
Published version
Author(s)
Chen, Z
Wang, X
Atkinson, A
Brandon, N
Type
Journal Article
Abstract
A combined experimental-numerical approach is used to characterise the fracture of a porous bulk ceramic material (La0.6Sr0.4Co0.2Fe0.8O3) with porosities of 5-45%, undergoing spherical indentation. The Gurson model was used in FEM to describe the densification of the porous material. Indentation-induced radial cracks were observed, when the applied nominal contact pressure exceeded threshold values, with no Hertzian ring-cone cracks found. FEM analysis indicated that the cracks propagated mainly during unloading, driven by the tensile hoop stress generated near the contact circle. The stress intensity at the crack tip was estimated using an approximate analysis of the FEM stress field to derive toughness values that were consistent with values determined by conventional methods, provided that the crack length is sufficiently large compared with the contact radius and can be measured accurately. The absence of ring-cone cracks in the elastic field during loading is due to the material’s high modulus-to-hardness ratio and the small indenter radius as predicted by established theory.
Date Issued
2016-05-28
Date Acceptance
2016-05-06
Citation
Journal of the European Ceramic Society, 2016, 36 (14), pp.3473-3480
ISSN
0955-2219
Publisher
Elsevier
Start Page
3473
End Page
3480
Journal / Book Title
Journal of the European Ceramic Society
Volume
36
Issue
14
Copyright Statement
© 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license
(http://creativecommons.org/licenses/by/4.0/).
(http://creativecommons.org/licenses/by/4.0/).
License URL
Sponsor
Engineering & Physical Science Research Council (EPSRC)
Grant Number
EP/J016454/1
Subjects
Materials
Materials Engineering
Publication Status
Published