Failure modes and 3D stress analysis method of thermal barrier coatings on turbine blades: Coupling creep and oxidation effects

Thermal barrier coatings (TBCs), serving as critical thermal protection systems for engine turbine blades, significantly enhance the high-temperature load-bearing capacity of hot-section components when combined with integrated cooling designs. However, these coatings remain highly susceptible to failure under harsh operating conditions. These failures are fundamentally driven by the complex evolution of internal mechanical and thermal responses over time. Consequently, a detailed understanding of coating failure modes and the quantitative characterization of their stress–strain states remain critical challenges in the life assessment of hot-section components. To address this, this paper proposes a three-dimensional stress evaluation method for coated turbine blades that accounts for creep deformation and oxidation. By combining analytical modeling with the finite element method (FEM), this approach overcomes the cross-scale computational challenges inherent to coated blades and correlates complex stress states with specific failure modes. First, the coated turbine blade is simplified into a multi-layered cylindrical tube model. Analytical stress formulations for each structural layer under creep and oxidation conditions are derived and subsequently validated against FEM results. Second, creep and tensile tests are conducted on coated specimens to systematically investigate the relationship between various stress states and failure mechanisms. Furthermore, by integrating the analytical models with FEM, a computational framework is established to bridge the macroscopic stress distribution of the entire blade with the localized stresses within the coating, thereby quantifying the influence of key parameters on coating stress. Ultimately, this study successfully correlates stress states with failure modes in coated blades subjected to thermo-mechanical loading. The proposed methodology provides a robust framework for evaluating coating stresses in complex engineering components, while the parametric sensitivity analyses offer theoretical guidance for the structural design of coatings.