Life Prediction Modeling Based on FOA and Interface Shapes Simulation Applicability Analysis of TBCs

Subjective selection of simulation interface shapes may introduce errors in the strength and fatigue analysis of thermal barrier coatings (TBCs). However, the applicability of different interface shapes for the TBCs simulation has rarely been investigated. Based on the TBCs thermal fatigue experiment, a finite element model is established and combined with the Fruit Fly Optimization Algorithm (FOA), a TBCs life prediction model is established. Then, five typical interface shapes, sawtooth, sinusoidal, semicircular, elliptical, and trapezoidal, are identified based on fine-scale photographs of the real interface morphology of the TBCs. Finally, the interface shape with the highest simulation applicability is identified through interface stress state analysis and life prediction error analysis, and verified through experiment. The results show that the stress maximum location of the sawtooth and trapezoidal interface shapes is inconsistent with the experimental onset of damage in TBCs, which proves that the applicability of the two shapes in the simulation of TBCs is not high. When applying equivalent strain for life prediction, the life prediction errors for the semicircular interface shape, elliptical interface shape, and sinusoidal interface shape are 72.84%, 61.74%, and 58.72%, respectively. The lowest life prediction error is obtained by using data from the sinusoidal interface shape. Therefore, the sinusoidal interface shape is the most applicable simplified shape for TBC simulation. Applying sinusoidal interface shape for additional TBCs life prediction with only 13.52% error, which verifies the accuracy of the methodology and conclusions of this study. These conclusions can inform accurate strength and fatigue simulation analysis of TBCs.