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Fracture mechanics analysis of microcracks in thermally cycled thermal barrier coatings

Liu, Yan LU ; Persson, Christer LU and Melin, Solveig LU (2004) In Journal of Thermal Spray Technology 13(3). p.377-380
Abstract
The effects from thermal shock loading on pre-existing microcracks within thermal barrier coatings (TBCs) have been investigated through a finite element based fracture mechanical analysis. The TBC system consists of a metallic bond coat and a ceramic top coat. The rough interface between the top and bond coats holds an alumina oxide layer. Stress concentrations at the interface due to the interface roughness, as well as the effect of residual stresses, were accounted for. At the eventual closure between the crack surfaces, Coulomb friction was assumed. To judge the risk of fracture from edge cracks and centrally placed cracks, the stress intensity factors were continuously monitored during the simulation of thermal shock loading of the... (More)
The effects from thermal shock loading on pre-existing microcracks within thermal barrier coatings (TBCs) have been investigated through a finite element based fracture mechanical analysis. The TBC system consists of a metallic bond coat and a ceramic top coat. The rough interface between the top and bond coats holds an alumina oxide layer. Stress concentrations at the interface due to the interface roughness, as well as the effect of residual stresses, were accounted for. At the eventual closure between the crack surfaces, Coulomb friction was assumed. To judge the risk of fracture from edge cracks and centrally placed cracks, the stress intensity factors were continuously monitored during the simulation of thermal shock loading of the TBC. It was found that fracture from edge cracks is more likely than from centrally placed cracks. It was also concluded that the propagation of an edge crack is already initiated during the first load cycle, whereas the crack tip position of a central crack determines whether propagation will occur. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
coatings, thermal barrier, finite element method, central crack, edge crack
in
Journal of Thermal Spray Technology
volume
13
issue
3
pages
377 - 380
publisher
Springer
external identifiers
  • wos:000223928200005
  • scopus:4844220517
ISSN
1544-1016
DOI
10.1361/10599630420407
language
English
LU publication?
yes
id
f0b68da0-0538-4dfd-a7a3-05cf9ed8316b (old id 267026)
date added to LUP
2007-10-24 20:14:36
date last changed
2017-04-23 03:44:33
@article{f0b68da0-0538-4dfd-a7a3-05cf9ed8316b,
  abstract     = {The effects from thermal shock loading on pre-existing microcracks within thermal barrier coatings (TBCs) have been investigated through a finite element based fracture mechanical analysis. The TBC system consists of a metallic bond coat and a ceramic top coat. The rough interface between the top and bond coats holds an alumina oxide layer. Stress concentrations at the interface due to the interface roughness, as well as the effect of residual stresses, were accounted for. At the eventual closure between the crack surfaces, Coulomb friction was assumed. To judge the risk of fracture from edge cracks and centrally placed cracks, the stress intensity factors were continuously monitored during the simulation of thermal shock loading of the TBC. It was found that fracture from edge cracks is more likely than from centrally placed cracks. It was also concluded that the propagation of an edge crack is already initiated during the first load cycle, whereas the crack tip position of a central crack determines whether propagation will occur.},
  author       = {Liu, Yan and Persson, Christer and Melin, Solveig},
  issn         = {1544-1016},
  keyword      = {coatings,thermal barrier,finite element method,central crack,edge crack},
  language     = {eng},
  number       = {3},
  pages        = {377--380},
  publisher    = {Springer},
  series       = {Journal of Thermal Spray Technology},
  title        = {Fracture mechanics analysis of microcracks in thermally cycled thermal barrier coatings},
  url          = {http://dx.doi.org/10.1361/10599630420407},
  volume       = {13},
  year         = {2004},
}