Thermal barrier coating multi-scale modeling and simulation method based on parameterized pore generation

Abstract

The present application relates to the technical field of high-temperature protective coating, in particular to a thermal barrier coating (TBC) multi-scale modeling and simulation method based on parameterized pore generation, which is particularly suitable for the simulation of thermal-mechanical coupling behavior of a ceramic layer containing rare earth elements, a yttrium stabilized zirconium oxide (YSZ) layer, a bonding layer and a high-temperature alloy substrate. Compared with the method of obtaining pores of the coating by SEM and then performing finite element modeling, the modeling method of the present application is simple, fast and can establish various ceramic layer models containing pores, without the need to make test samples to generate finite element models. Compared with the method of directly assuming uniform distribution of pores in the finite element and converting the influence of the pores on the coating into changes in the material parameters of the coating, the present method realizes accurate quantitative control of the pore parameters, meeting the design requirements of the microstructure of the thermal barrier coating. In the present model, the pores are randomly distributed and overlapping of the pores in the coating is avoided, simulating the non-uniformity of the real coating.

Description

Technical Field

[0001] This invention relates to the field of high-temperature protective coating technology, specifically to a multi-scale modeling and simulation method for thermal barrier coatings based on parameterized pore generation. Background Technology

[0002] Traditional thermal barrier coating simulation systems typically consist of a ceramic top layer (such as YSZ), a binder layer (MCrAlY alloy), and a high-temperature alloy substrate. Finite element simulation of the coating system is an effective method for coating failure analysis. However, existing technologies have the following shortcomings: When modeling the pore morphology in the coating obtained by SEM, the pores can only represent a single sample and cannot reflect the comprehensive influence of various pore factors such as porosity and pore orientation on the stress of the thermal barrier coating.

[0003] When modeling the pore structure of ceramic layers relies on a simplified pore model, it assumes that the pores are completely identical and uniformly distributed. This transforms the influence of pores on coating stress into changes in coating material parameters caused by pores, which cannot directly reflect the influence of pores formed by actual atmospheric plasma spraying processes on coating stress. Summary of the Invention

[0004] To address the above issues and overcome the shortcomings of existing technologies, the present invention aims to provide a multi-scale modeling and simulation method for thermal barrier coatings based on parametric porosity generation. This method is particularly suitable for simulating the thermo-mechanical coupling behavior of rare-earth element-containing ceramic layers, yttrium oxide-stabilized zirconia (YSZ) layers, binder layers, and high-temperature alloy substrates. It can accurately predict the residual stress distribution of porous thermal barrier coatings under thermal and mechanical loading conditions. This method has the advantages of accurate prediction and rapid calculation.

[0005] To achieve the above objectives, this invention proposes a multi-scale modeling method for thermal barrier coatings based on parameterized pore generation, comprising the following steps: (1) Set model parameters: matrix size (L×H), target value of elliptical porosity, range of major axis of elliptical pore [a_min,a_max] and safety factor α; (2) Execute intelligent collision avoidance algorithm: (21) Dynamically generate elliptical pores; (22) Calculate the safe distance between two elliptical pores S_safe=(a_i+a_j)×α; (23) Implement three-level collision detection: size over-limit detection → boundary safety detection → inter-pore interference detection; (3) Build parameterized model through ABAQUS Python interface: (31) Generate geometric entity according to the pore center coordinates (x,y) and elliptical rotation angle θ output in step (2); (32) Use RemoveFaces command to perform pore cutting.

[0006] Furthermore, the safety factor α satisfies 1.05≤α≤1.5, and is dynamically adjusted as: α=1.1+0.4×(A_current / A_target); where A_current is the current cumulative pore area, and A_target is the target pore area.

[0007] Furthermore, the three-level collision detection specifically includes: (a) Size over-limit detection: if the area of ​​the new hole plus the current cumulative area is greater than 1.05 × the target area, then the hole is discarded; (b) Boundary safety detection: the center coordinates (x, y) of the hole must satisfy: x∈[a_i×α,L-a_i×α] y∈[a_i×α,H-a_i×α] (c) Inter-hole interference detection: calculate the center distance d_ij between the new hole and the existing hole, and if there exists d_ij<(a_i+a_j)×α, then a collision is determined.

[0008] Furthermore, in step (2), the rotation angle θ of the elliptical aperture is randomly generated, θ∈[0,2π], and the safety distance calculation adopts the most unfavorable working condition in the direction of the major axis of the ellipse.

[0009] Furthermore, the ratio γ of the major and minor axes of the elliptical aperture satisfies: 1.0≤γ≤4.0; and the area of ​​the ellipse is calculated using the formula: A_e=π×a×b, where a is the radius of the major axis and b is the radius of the minor axis.

[0010] Furthermore, it also includes a circuit breaker protection mechanism, including the following steps: (41) Set the maximum number of attempts N_max∈[10000,50000]; (42) Terminate the generation when the number of attempts > N_max and output the current optimal distribution.

[0011] Another objective of this invention is to provide a simulation method for a multi-scale model of thermal barrier coatings based on parameterized pore generation. By applying the above-mentioned multi-scale modeling method for thermal barrier coatings based on parameterized pore generation, at least one of the following analyses can be performed: thermal stress distribution calculation, crack propagation calculation, and thermal cycle life assessment.

[0012] Beneficial effects: 1. Compared with obtaining the pores of the coating using SEM and then performing finite element modeling, the modeling method of the present invention is simple, fast and can establish a variety of different ceramic layer models with pores. It can generate finite element models without the need to make test samples. 2. Compared with directly assuming that pores are distributed in the finite element method and converting the influence of pores on the coating into changes in coating material parameters, this method achieves precise quantitative control of pore parameters, which meets the microstructure design requirements of thermal barrier coatings. 3. In this model, the pores are randomly distributed, and the overlap of pores in the coating is avoided to simulate the non-uniformity of the real coating.

[0013] Additional aspects and advantages of the invention will be set forth in the description which follows, and in some respects will be obvious from the description or may be learned by practice of the invention. Attached Figure Description

[0014] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a diagram showing the internal pore model of LMA and YSZ with pores according to an embodiment of the present invention; Figure 2 This is a diagram of the internal pore parameters LMA and YSZ of the pores in a Python script according to an embodiment of the present invention; Figure 3 This is a geometric dimension drawing of the geometric model of TGO, BC and substrate K423A according to an embodiment of the present invention; Figure 4 This is a stress diagram of the S22 point at the trough of the YSZ / TGO interface under different porosities according to an embodiment of the present invention; Figure 5 This is a stress diagram of the S11 at the trough point on the YSZ / TGO interface for different pore orientations according to an embodiment of the present invention. Figure 6 This is a flowchart illustrating the modeling and simulation process according to an embodiment of the present invention. Detailed Implementation

[0015] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0016] The following description, in conjunction with the accompanying drawings, illustrates a multi-scale modeling and simulation method for thermal barrier coatings (TBCs) based on parameterized pore generation, according to an embodiment of the present invention.

[0017] This invention relates to the field of high-temperature protective coating technology, specifically to a multi-scale modeling method and system for thermal barrier coatings (TBC) based on parametric pore generation. It is particularly suitable for simulating the thermo-mechanical coupling behavior of rare earth element ceramic layers, yttrium oxide-stabilized zirconia (YSZ) layers, adhesive layers, and high-temperature alloy substrates, and can accurately predict the residual stress distribution under thermal shock conditions.

[0018] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A multi-scale modeling and simulation method for thermal barrier coatings based on parametric pore generation, wherein the modeling method includes the following steps: 1. Create a CAE model, Model-1, in Abaqus.

[0019] 2. In a Python script, set the porosity, pore direction, pore major axis dimension range, and pore major-minor axis ratio. Run the Python script in Abaqus software to generate Model-2, which contains porous LMA and YSZ geometric models, such as... Figure 1 As shown in the figure, the upper half represents the porous LMA layer, and the lower half represents the porous YSZ layer. Ellipses represent pores.

[0020] In this step, the reasonable range for porosity is 0-20%, the pore direction is 0-360°, the pore major axis dimension is 1.0-10µm, and the ratio of major to minor axis is 1.0-4.5.

[0021] During the execution of the Python script, parameters such as porosity, pore direction, pore size, target value of the ratio of the major and minor axes of the pores, actual value of porosity, number of pores, and time taken to generate the model will be output simultaneously.

[0022] like Figure 2 As shown in the figure, the Target pore area in the top box is the total pore area target value of 0.0018 mm, calculated based on the total area of ​​YSZ and the set porosity. 2 The target porosity is set at 20%, the maximum target porosity is 0.0075 mm, and the ratio of the major axis to the minor axis of the porosity is 3.0.

[0023] The "Pore generation conpleted in .1 seconds" in the middle box indicates that the YSZ pores were generated within 0.1 seconds, with a total of 123 pores generated and an actual porosity of 20.13%.

[0024] The information in the bottom box indicates that the LMA width and height information were generated as required, resulting in a total of 163 pores. The ratio of the major axis to the minor axis of the pores is 3.0, and the angle between the major axis of the pores and the horizontal X-axis is 0 degrees.

[0025] 3. Copy the LMA and YSZ parts with pores generated in Model-2 to Model-1 using the Copy objects command.

[0026] 4. Create geometric models of TGO, BC, and matrix K423A in Model-1. The model dimensions are as follows: Figure 3As shown in the figure, the thicknesses of each thermal barrier coating layer are listed. The thicknesses of LMA, YSZ, BC, and K423A layers are 200um, 150um, 150um, and 1mm, respectively. The thickness of the TGO layer is 4um, and the model width is 60um. The cross-sections of the BC / TGO layer and the LMA / TGO layer are cosine curves with an amplitude of 10um.

[0027] 5. In Model-1, set the material elasticity, plasticity, and creep parameters of LMA, YSZ, TGO, BC, and the matrix, and specify the cross-sectional properties of each part.

[0028] 6. In the assembly module, create instances for each part.

[0029] 7. Mesh the LMA, YSZ, TGO, BC, and substrate layers, specifying the mesh type as CPE4T. Set the mesh size for LMA and YSZ to 1µm. Use an offset method to mesh the adhesive layer and substrate, with the mesh size gradually increasing from top to bottom.

[0030] 8. Establish a coupled temperature-displacement analysis step, set the analysis step time to 840 seconds, enable large deformation, select transient response type, and set the initial increment step to 1.

[0031] 9. Set the left side of the model as a symmetry constraint, and fix the bottom surface of the base metal.

[0032] 10. Apply time-varying temperature boundary conditions to the top layer of the LMA. The top layer of the LMA is raised from room temperature (25°C) to 1200°C within 120 seconds, held at 1200°C for 600 seconds, and then rapidly cooled back to room temperature (25°C) within 120 seconds.

[0033] 11. Set binding constraints for the contact positions of each part.

[0034] 12. Submit Job-1 and perform finite element simulation analysis to obtain the stress S11 and S22 at the YSZ and TGO interfaces.

[0035] 13. Repeat steps 1-12 to perform finite element simulations for different porosities and pore morphologies.

[0036] 14. By comparing the stress under different pore sizes, the influence of pores on the stress of thermal barrier coatings can be analyzed, such as... Figure 4 , Figure 5 As shown.

[0037] Figure 4 The figure shows the internal residual stress S22 values ​​along the Y-axis at the trough of the cosine curve when the porosity is 0%, 5%, 10%, 15%, and 20%, respectively.

[0038] Figure 5 The figure shows the internal residual stress S11 values ​​along the X-axis at the trough position when the angle between the principal axis and the X-axis of the elliptical pore is 0°, 45°, 90° and 135° respectively.

[0039] In summary, this invention can accurately predict the residual stress distribution of porous thermal barrier coatings under thermal and mechanical loading conditions. This method has the advantages of accurate prediction and rapid calculation.

[0040] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A multi-scale modeling method for thermal barrier coatings based on parametric pore generation, characterized in that, Includes the following steps: (1) Set model parameters: matrix size (L×H), target value of elliptical porosity, range of major axis of elliptical pore [a_min,a_max] and safety factor α; (2) Execute intelligent collision avoidance algorithm: (21) Dynamically generate elliptical pores; (22) Calculate the safe distance between two elliptical pores S_safe=(a_i+a_j)×α; (23) Implement three-level collision detection: size over-limit detection-boundary safety detection-inter-pore interference detection; (3) Build parameterized model through ABAQUS Python interface: (31) Generate geometric entity according to the pore center coordinates (x,y) and elliptical rotation angle θ output in step (2); (32) Use RemoveFaces command to perform pore cutting.

2. The multi-scale modeling method for thermal barrier coatings based on parameterized pore generation according to claim 1, characterized in that, The safety factor α satisfies 1.05≤α≤1.5, and is dynamically adjusted as: α=1.1+0.4×(A_current / A_target); where A_current is the current cumulative pore area, and A_target is the target pore area.

3. The multi-scale modeling method for thermal barrier coatings based on parameterized pore generation according to claim 1, characterized in that, The three-level collision detection specifically includes: (a) Size over-limit detection: If the area of ​​the new hole plus the current cumulative area is greater than 1.05 × the target area, then the hole is discarded; (b) Boundary safety detection: The center coordinates (x, y) of the hole must satisfy: x∈[a_i×α,L-a_i×α] y∈[a_i×α,H-a_i×α] (c) Inter-hole interference detection: Calculate the center distance d_ij between the new hole and the existing hole. If there exists d_ij<(a_i+a_j)×α, then a collision is determined.

4. The multi-scale modeling method for thermal barrier coatings based on parameterized pore generation according to claim 1, characterized in that, In step (2), the rotation angle θ of the elliptical aperture is randomly generated, θ∈[0,2π], and the safety distance calculation adopts the most unfavorable working condition in the direction of the major axis of the ellipse.

5. The multi-scale modeling method for thermal barrier coatings based on parameterized pore generation according to claim 1, characterized in that, The ratio γ of the major and minor axes of the elliptical aperture satisfies: 1.0≤γ≤4.0; and the area of ​​the ellipse is calculated using the formula: A_e=π×a×b, where a is the radius of the major axis and b is the radius of the minor axis.

6. The multi-scale modeling method for thermal barrier coatings based on parameterized pore generation according to claim 1, characterized in that, It also includes a circuit breaker protection mechanism, including the following steps: (41) Set the maximum number of attempts N_max∈[10000,50000]; (42) Terminate the generation when the number of attempts > N_max and output the current optimal distribution.

7. A simulation method for a multi-scale model of a thermal barrier coating based on parameterized pore generation, characterized in that, The multi-scale modeling method for thermal barrier coatings based on parametric pore generation according to any one of claims 1-6 can perform at least one of the following analyses: thermal stress distribution calculation; Crack propagation calculation; thermal cycling life assessment.

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