The use of experimental bending tests to more accurate numerical description of TBC damage process

3rd International Conference on Competitive Materials and Technology Processes

Sadowski, T.^1 ; Golewski, P.^1

Faculty of Civil Engineering and Architecture, Lublin University of Technology Lublin, Poland^1

关键词: Cohesive behaviors;    Corrosive environment;    Experimental testing;    High rotational speed;    Microscopic observations;    Strength property;    Thermal barrier coating (TBCs);    Three-point bending test;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/123/1/012017/pdf
DOI  :  10.1088/1757-899X/123/1/012017

来源: IOP

【 摘 要 】

Thermal barrier coatings (TBCs) have been extensively used in aircraft engines to protect critical engine parts such as blades and combustion chambers, which are exposed to high temperatures and corrosive environment. The blades of turbine engines are additionally exposed to high mechanical loads. These loads are created by the high rotational speed of the rotor (30 000 rot/min), causing the tensile and bending stresses. Therefore, experimental testing of coated samples is necessary in order to determine strength properties of TBCs. Beam samples with dimensions 50×10×2 mm were used in those studies. The TBC system consisted of 150 μm thick bond coat (NiCoCrAlY) and 300 μm thick top coat (YSZ) made by APS (air plasma spray) process. Samples were tested by three-point bending test with various loads. After bending tests, the samples were subjected to microscopic observation to determine the quantity of cracks and their depth. The above mentioned results were used to build numerical model and calibrate material data in Abaqus program. Brittle cracking damage model was applied for the TBC layer, which allows to remove elements after reaching criterion. Surface based cohesive behavior was used to model the delamination which may occur at the boundary between bond coat and top coat.