| Modern gas turbine engines have routinely utilized thermal barrier coatings for the past three decades to coax greater thermodynamic efficiency out of jet engines. In service, it has been noted that these ceramic materials are also effective at suppressing high cycle fatigue in the engine components, increasing their respective fatigue life. Recent efforts have been made to mechanically characterize these materials; this has been a challenge as they are thin coatings, prone to history effects, and are materially nonlinear. Refinement of the apparatus have occurred and it is now desired to characterize them across a range of likely service temperatures.;A free-free beam apparatus has been adapted to accomplish this. Important to achieving viable results is the design, analysis, and experimental validation of the chamber in regards to the free-free specimen being heat-able, modally detuned and free-hanging, and the preservation of a non-contacting excitation method. Critical to success is ensuring a near-isothermal heated beam specimen. After successful validation and calibration of the chamber, a common thermal barrier coating, 8-YSZ, was tested, primarily using the free-decay, logarithmic decrement method, using the chamber from 70-900degF. Materially non-linear behavior was observed and findings of material storage modulus and loss coefficient that are consistent with previous studies were obtained. The chamber was also used to characterize the bare metal beam blanks and bond-coat only specimens. The apparatus was found to be sensitive when determining the storage modulus and damping, more so than the baseline configuration. This was due to changes in design to proof it against high temperature. Resulting, it clearly characterized the anisotropic modulus of titanium and determined that bond coating had a negligible contribution to the beam system. Design life criteria with the properties of the coating could now be adopted across a range of temperatures. |
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