Evaluation of the Accuracy of Young's Moduli of Thermal Barrier Coatings Determined on the Basis of Composite Beam Theory

摘要

The Young's modulus of thermal barrier coating (TBC) is an important mechanical property as it is required for calculating the parameters of material mechanics in the TBC system. In this study, we investigated the accuracy of the Young's modulus of TBC calculated using the composite beam theory. Generally, both the Young's modulus and the thickness of TBC are approximately one order of magnitude lower than those of the substrate. Consequently, the Young's modulus of the TBC calculated on the basis of the composite beam theory is considerably sensitive to experimental errors. In order to improve the accuracy of the composite beam method, methods that make use of coating strain, substrate strain, or deflection were compared. The methods with low sensitivity to experimental errors were determined through sensitivity analysis. Further, the effectiveness of the methods with low sensitivity was confirmed experimentally.