Fracture mechanics analysis of microcracks in thermally cycled thermal barrier coatings
Författare
Summary, in English
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.
Avdelning/ar
Publiceringsår
2004
Språk
Engelska
Sidor
377-380
Publikation/Tidskrift/Serie
Journal of Thermal Spray Technology
Volym
13
Issue
3
Dokumenttyp
Artikel i tidskrift
Förlag
Springer
Ämne
- Materials Engineering
- Applied Mechanics
Nyckelord
- coatings
- thermal barrier
- finite element method
- central crack
- edge crack
Status
Published
ISBN/ISSN/Övrigt
- ISSN: 1544-1016