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Thermal barrier coating life prediction model development, phase 1The objective of this program was to establish a methodology to predict thermal barrier coating (TBC) life on gas turbine engine components. The approach involved experimental life measurement coupled with analytical modeling of relevant degradation modes. Evaluation of experimental and flight service components indicate the predominant failure mode to be thermomechanical spallation of the ceramic coating layer resulting from propagation of a dominant near interface crack. Examination of fractionally exposed specimens indicated that dominant crack formation results from progressive structural damage in the form of subcritical microcrack link-up. Tests conducted to isolate important life drivers have shown MCrAlY oxidation to significantly affect the rate of damage accumulation. Mechanical property testing has shown the plasma deposited ceramic to exhibit a non-linear stress-strain response, creep and fatigue. The fatigue based life prediction model developed accounts for the unusual ceramic behavior and also incorporates an experimentally determined oxide rate model. The model predicts the growth of this oxide scale to influence the intensity of the mechanic driving force, resulting from cyclic strains and stresses caused by thermally induced and externally imposed mechanical loads.
Document ID
19900004072
Acquisition Source
Legacy CDMS
Document Type
Contractor Report (CR)
Authors
Demasi, Jeanine T.
(Pratt and Whitney Aircraft East Hartford, CT, United States)
Ortiz, Milton
(Pratt and Whitney Aircraft East Hartford, CT, United States)
Date Acquired
September 6, 2013
Publication Date
December 1, 1989
Subject Category
Aircraft Propulsion And Power
Report/Patent Number
NASA-CR-182230
PWA-5970-40
NAS 1.26:182230
Accession Number
90N13388
Funding Number(s)
CONTRACT_GRANT: NAS3-23944
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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