Optics: measuring and testing – Material strain analysis
Patent
1997-03-03
2000-06-06
Rosenberger, Richard A.
Optics: measuring and testing
Material strain analysis
73800, G01N 2164
Patent
active
060725680
ABSTRACT:
A non-destructive measurement method for determining residual stress proximate an intermediate layer in a multilayer thermal barrier coating system by directing a laser beam through an outer ceramic thermal insulating layer with the laser beam illuminating a ceramic-bearing intermediate layer in a manner to cause species present in the intermediate layer to fluoresce, measuring the frequency of the light or photons emitted by the fluroescing species, and comparing the measured frequency shift of the intermediate ceramic layer to the frequency shift determined on like ceramic material under controlled stress states to determine a representation of relative residual stress in the measured coating. The invention can be used to assess integrity or quality control of as-manufactured TBC coatings or to assess remaining coating service life of engine-run TBC coated components during an inspection or repair procedure.
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Clarke David R.
Murphy Kenneth S.
Paton Neil E.
Howmet Research Corporation
Rosenberger Richard A.
Timmer Edward J.
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