Vibration Analysis of Commercial Thermal Barrier Coatings; Master's Thesis

摘要

Thermal barrier coatings (TBCs) are currently used in turbine engine components to protect substrate material from exposure to high temperature and corrosion. These coatings have the potential to reduce stress in critical engine parts which could increase the life cycle of these parts. The fact that these coatings are already qualified for use in turbine engines makes it worth investigating their damping properties. The problem with TBCs is that they are difficult to characterize as they display nonlinear properties. This research utilizes an experimental and finite element procedure to characterize these coatings. A scanning electron microscope (SEM) was employed to observe the microstructure contribution to the damping properties. This program utilizes a testing method which employs a test setup that attempts to eliminate any external factors which may add any unwanted damping. The major contributions of this research are: a comparison of the material properties of two different TBCs, magnesium aluminate spinel and yttria stabilized zirconia; the confirmation that sweep rate does not cause data recorded in the log decrement method to coincide with data recorded with the half-power bandwidth method; and SEM images that confirm the damping properties of plasma sprayed TBCs are directly related to the microcrack structure of a coating.