A co-existing thermal-solidification solution method for CMC materials incorporating a probabilistic model

Abstract

This invention discloses a method for solving the solid-thermal coupling problem of CMC materials using a probabilistic model, belonging to the field of engineering thermophysics. This method addresses the mechanical damage that occurs in high-temperature CMC components after long-term service. It establishes a representative unit cell RVE model of the CMC material at the microscale, considering the stochastic characteristics of mechanical damage, and incorporates the characteristic patterns of mechanical damage occurring in the CMC material after long-term service into a complete RVE model. Based on this model, by applying axial and radial thermal boundary conditions respectively, the axial and radial thermal conductivity of the CMC material at the microscale are obtained. The corresponding elastic modulus is calculated using the CMC material matrix crack density formula and stress-strain relationship, establishing a mapping relationship between the thermophysical parameters and mechanical performance parameters of the CMC material when mechanical damage occurs, thus realizing the solid-thermal coupling analysis and solution of the CMC material after stochastic mechanical damage. Therefore, this method can improve the accuracy of temperature field prediction for high-temperature CMC components under long-term service conditions.

Description

Technical Field

[0001] This invention relates to the field of engineering thermophysics, and in particular to a method for solving CMC materials using a probabilistic model that incorporates solid-thermal coupling. Background Technology

[0002] CMC (Ceramic Matrix Composite) is a high-performance composite material composed of a ceramic matrix, fiber-reinforced phase, and an interface layer between the matrix and fibers. It possesses characteristics such as high temperature resistance, low density, and strong thermal stability. However, its temperature limit of 1623K is still lower than the ultra-high temperature of over 2200K at the turbine inlet of future advanced aero-engines. To avoid material damage or even failure due to overheating, appropriate cooling technologies are still needed to cool CMC high-temperature components. Therefore, a high-precision thermal analysis model of CMC high-temperature components is required to accurately obtain its temperature field and other characteristics. Due to the microscopic characteristics of the reinforcing fibers within CMC, there are significant differences in axial and radial thermal conductivity within the fibers. Furthermore, the significant differences in strength and thermal conductivity between the reinforcing fibers and the matrix lead to heterogeneity, resulting in significant anisotropy in the material properties of CMC, such as strength and thermal conductivity. Therefore, traditional thermal analysis methods for isotropic metallic alloys are no longer applicable in the design of high-temperature components for aero-engines. It is necessary to establish methods for predicting and analyzing the anisotropic thermal properties of CMC materials.

[0003] During the operation of aero-engines, their aero-thermal parameters are typically highly variable. In addition to high thermal loads, CMC materials, as high-temperature components, also face aerodynamic loads in their actual service environment. Because the temperature of the high-temperature exhaust gases from the combustion chamber is non-uniform, there are significant temperature gradients in the hot-end components of aero-engines. However, CMC materials are particularly sensitive to thermal stress due to the large difference in thermal expansion coefficients between the fibers and the matrix. NASA reports that turbine inlet temperatures above 1750K necessitate detailed analysis and strict requirements for the stress levels of CMC turbine components, as the internal stress caused by temperature differences significantly affects the strength of the reinforcing fibers within the CMC. Under the complex coupling of alternating thermo-mechanical loads, CMC materials can experience various forms and degrees of mechanical damage, such as matrix cracking, interfacial layer debonding, and fiber breakage. This leads to changes in the material's microstructure, affecting its mechanical and thermophysical properties, and consequently, the temperature field of the high-temperature CMC components. In practical engineering applications, CMC materials inevitably suffer mechanical damage. Due to the heterogeneous nature of the material, the equivalent thermal conductivity of CMC materials exhibits obvious anisotropic characteristics. If the impact of damage is not considered, it will be difficult to accurately predict the temperature field of CMC materials under service conditions. Summary of the Invention

[0004] This invention provides a co-mechanical solution method for CMC materials incorporating a probabilistic model. To accurately predict the temperature field requirements of CMC materials after mechanical damage, and considering the heterogeneous and anisotropic characteristics of CMC materials, traditional thermal analysis methods based on homogeneous metals and those that do not consider mechanical damage struggle to reflect the impact of mechanical damage characteristics on internal heat transfer, temperature field distribution, and thermal stress distribution. Therefore, this invention employs a co-mechanical solution method for CMC materials incorporating a probabilistic model to achieve accurate prediction of the temperature field and thermal stress of CMC materials after mechanical damage.

[0005] This invention provides a method for solving CMC materials using a probabilistic model that integrates solid-thermal coupling, comprising the following steps:

[0006] Step 1: Construct a parametric RVE model of the microstructure of the CMC material using the commercial software COMSOL;

[0007] Step 2: Based on the mechanical damage characteristics of CMC materials, use random functions in COMSOL to randomly introduce the mechanical damage characteristics into the microscopic RVE parameterized model of intact and undamaged CMC materials;

[0008] Step 3: Apply thermal boundary conditions in the axial and radial directions of the micro-based RVE model respectively, and analyze the effects of different mechanical damages and their characteristics on the axial and radial thermal conductivity of the CMC material after mechanical damage occurs using COMSOL analysis.

[0009] Step 4: By changing the fiber diameter, the influence of random fiber diameter distribution on the radial and axial thermal conductivity of CMC materials is studied. The damage rate of CMC materials is changed by altering the number of damages in the RVE parameterized model of the microstructure of intact CMC materials. The influence of the damage rate on the axial and radial thermal conductivity of CMC materials is studied and analyzed. The elastic modulus of CMC materials under different damage rates is calculated using the matrix crack density and stress-strain relationship. The mapping function relationship between the thermophysical parameters and mechanical performance parameters of CMC materials after mechanical damage is established, realizing the solution of the solid-thermal coupling analysis of CMC materials after mechanical damage.

[0010] Optionally, in one embodiment of the present invention, in step 1, a complete and undamaged parametric micro-foundation RVE model of CMC material is constructed using commercial software COMSOL. The micro-foundation RVE model is established based on SEM images of CMC material and includes fibers, interface layers and matrix. The various dimensional parameters of the micro-foundation RVE model are assigned values ​​through the defined parameters in COMSOL to achieve parametric modeling.

[0011] Optionally, in one embodiment of the present invention, in step 2, the mechanical damage characteristics of the CMC material are obtained based on the SEM image of the CMC material, a random function is generated in COMSOL, the damage location is assigned by the generated random function, and the mechanical damage characteristics are introduced into the microscopic basic RVE parameterized model of the intact and undamaged CMC material.

[0012] Optionally, in one embodiment of the present invention, in step 3, the mechanical damage characteristics refer to the location of mechanical damage in the CMC material and the fiber diameter of the CMC material. By generating a random function in COMSOL, the mechanical damage location and fiber diameter of the CMC material are randomly assigned. By setting two different thermal boundary conditions, axial and radial, on the microscopic basic RVE model, the physical field information of the axial temperature field, heat flux density field and radial temperature field of the CMC material after mechanical damage is obtained. The influence of different damage forms on the internal heat transfer of the CMC material is analyzed. The axial thermal conductivity and radial thermal conductivity of the CMC material are calculated using the Fourier formula.

[0013] Optionally, in one embodiment of the present invention, in step 3, the axial thermal conductivity and radial thermal conductivity of the CMC material are calculated using the Fourier formula as follows:

[0014]

[0015] In the formula, k is the axial thermal conductivity and radial thermal conductivity, q is the heat passing through a unit area cross section per unit time, Δx is the length change value perpendicular to the unit area cross section, and ΔT is the temperature change value perpendicular to the unit area cross section.

[0016] Optionally, in one embodiment of the present invention, in step 4, the crack density of the CMC material matrix is ​​calculated as follows:

[0017]

[0018] In the formula, D is the matrix crack density, D sat Let σ be the final density when the crack reaches saturation, and σ be the stress on the CMC material. m Both m and are statistical parameters;

[0019] The stress-strain relationship is:

[0020]

[0021] In the formula, ε is the strain of the CMC material, and E f V is the fiber elastic modulus, L is the matrix crack spacing, and V is the fiber elastic modulus. f d is the volume fraction of the fiber, d is the debonding length of the CMC material interface layer, and r is the volume fraction of the fiber. f σ is the diameter of the fiber.f0 α represents the normal stress of the CMC material when it is undamaged. f α is the coefficient of thermal expansion of the fiber. c ΔT1 is the coefficient of thermal expansion of CMC material, and ΔT1 is the temperature difference between the preparation of CMC material and cooling to room temperature.

[0022] The elastic modulus of CMC material under different damage rates was calculated using the matrix crack density and stress-strain relationship:

[0023]

[0024] In the formula, E is the elastic modulus of CMC material;

[0025] Establish the mapping function relationship between the thermophysical parameters and mechanical properties of CMC materials after mechanical damage, and realize the solution of the solid-thermal coupling analysis of CMC materials after mechanical damage:

[0026] σ T =E(ε-αΔT1)

[0027] In the formula, σ T α represents the thermal stress on the CMC material, and α is the coefficient of thermal expansion of the CMC material.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] This invention addresses the accurate prediction of temperature field and thermal stress requirements for high-temperature CMC (Continuous Metal Structure) components in aero-engines after mechanical damage. Based on a parametric model of CMC materials considering mechanical damage, it studies the impact of mechanical damage on the temperature field distribution and internal heat transfer of CMC materials, and further establishes a coherent solid-thermal coupling solution method for CMC materials incorporating a probabilistic model. This invention establishes a microscopic model of CMC materials considering mechanical damage, solving the modeling problem for CMC materials under such conditions and improving the accuracy of temperature field prediction for high-temperature CMC components under long-term service environments.

[0030] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0031] 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:

[0032] Figure 1 A flowchart illustrating a method for solving CMC materials using a probabilistic model, according to an embodiment of the present invention;

[0033] Figure 2 This is a schematic diagram of the RVE parameterized model of the microstructure of intact and undamaged CMC material according to an embodiment of the present invention;

[0034] Figure 3 This is a schematic diagram of the RVE parameterization model of the microstructure of CMC material with mechanical damage introduced in an embodiment of the present invention;

[0035] Figure 4 This is a structured mesh partitioning diagram of the microscopic basic RVE parameterized model according to an embodiment of the present invention;

[0036] Figure 5 This is a diagram showing the boundary condition settings for the microscopic basic RVE parameterized model in an embodiment of the present invention.

[0037] Figure 6 This is a turbine blade model made of CMC material, as described in an embodiment of the present invention. Detailed Implementation

[0038] 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.

[0039] The following describes a method for solving the thermal-physical coupling problem of CMC materials using a probabilistic model, based on an embodiment of the present invention, with reference to the accompanying drawings. Addressing the issue mentioned in the background art that the equivalent thermal conductivity of CMC materials exhibits significant anisotropy, making it difficult to accurately predict the temperature field of CMC materials under service conditions without considering the impact of damage, the present invention provides a method for solving the thermal-physical coupling problem of CMC materials using a probabilistic model. This method performs anisotropic thermal conductivity analysis of CMC materials considering mechanical damage. By establishing a microscale analysis model reflecting the characteristics of mechanical damage in the material, and under isothermal boundary conditions in different directions, it analyzes the influence of different damage characteristics and damage rates on the thermal conductivity in different directions of the material. This explores the impact of mechanical damage on the material's equivalent thermal conductivity and internal heat transfer mechanism, thereby establishing a method for solving the thermal-physical coupling problem of CMC materials considering mechanical damage.

[0040] Figure 1 This is a flowchart illustrating a method for solving CMC materials using a probabilistic model, according to an embodiment of the present invention.

[0041] like Figure 1 As shown, this method for solving CMC materials using a probabilistic model includes the following steps:

[0042] Step 1: Use the commercial software COMSOL to construct a complete and undamaged RVE parameterized model of the microstructure of CMC materials.

[0043] In one embodiment of the present invention, in step 1, a complete and undamaged parametric micro-foundation RVE model of CMC material is constructed using commercial software COMSOL. The micro-foundation RVE model is established based on SEM images of CMC material and includes fibers, interface layers and matrix. The dimensional parameters of the micro-foundation RVE model are assigned values ​​through the defined parameters in COMSOL to achieve parametric modeling.

[0044] Step 2: Based on the mechanical damage characteristics of CMC materials, use random functions in COMSOL to randomly introduce the mechanical damage characteristics into the microscopic RVE parameterized model of intact and undamaged CMC materials.

[0045] In one embodiment of the present invention, in step 2, the mechanical damage characteristics of the CMC material are obtained based on the SEM image of the CMC material, a random function is generated in COMSOL, the damage location is assigned by the generated random function, and the mechanical damage characteristics are introduced into the microscopic basic RVE parameterized model of the intact and undamaged CMC material.

[0046] Step 3: Apply thermal boundary conditions in the axial and radial directions of the micro-based RVE model respectively, and analyze the effects of different mechanical damages and their characteristics on the axial and radial thermal conductivity of the CMC material after mechanical damage occurs using COMSOL.

[0047] In one embodiment of the present invention, in step 3, the mechanical damage characteristics refer to the location of mechanical damage in the CMC material and the fiber diameter of the CMC material. By generating a random function in COMSOL, the mechanical damage location and the fiber diameter of the CMC material are randomly assigned. By setting two different thermal boundary conditions, axial and radial, on the microscopic basic RVE model, the physical field information of the axial temperature field, heat flux density field and radial temperature field of the CMC material after mechanical damage is obtained. The influence of different damage forms on the internal heat transfer of the CMC material is analyzed. The axial thermal conductivity and radial thermal conductivity of the CMC material are calculated using the Fourier formula.

[0048] Furthermore, the axial thermal conductivity and radial thermal conductivity of the CMC material were calculated using Fourier's formula as follows:

[0049]

[0050] In the formula, k is the axial thermal conductivity and radial thermal conductivity, q is the heat passing through a unit area cross section per unit time, Δx is the length change value perpendicular to the unit area cross section, and ΔT is the temperature change value perpendicular to the unit area cross section.

[0051] Step 4: By changing the fiber diameter, the influence of random fiber diameter distribution on the radial and axial thermal conductivity of CMC materials is studied. The damage rate of CMC materials is changed by altering the number of damages in the RVE parameterized model of the microstructure of intact CMC materials. The influence of the damage rate on the axial and radial thermal conductivity of CMC materials is studied and analyzed. The elastic modulus of CMC materials under different damage rates is calculated using the matrix crack density and stress-strain relationship. The mapping function relationship between the thermophysical parameters and mechanical performance parameters of CMC materials after mechanical damage is established, realizing the solution of the solid-thermal coupling analysis of CMC materials after mechanical damage.

[0052] In step 4, different mechanical damage characteristics are introduced to study the effects of different mechanical damage forms on CMC materials. The damage rate of CMC materials is changed by introducing different numbers of damage characteristics. Calculation conditions with damage rates of 0%, 1%, 2%, 3%, and 5% are set to study the effects of different damage degrees on CMC materials.

[0053] In one embodiment of the present invention, the crack density of the CMC material matrix in step 4 is calculated as follows:

[0054]

[0055] In the formula, D is the matrix crack density, D sat Let σ be the final density when the crack reaches saturation, and σ be the stress on the CMC material. m Both σ and m are statistical parameters; in this example, m = 5, σ m =160MPa,D sat =2.5mm -1 .

[0056] The stress-strain relationship is:

[0057]

[0058] In the formula, ε is the strain of the CMC material, and E f V is the fiber elastic modulus, L is the matrix crack spacing, and V is the fiber elastic modulus. f d is the volume fraction of the fiber, d is the debonding length of the CMC material interface layer, and r is the volume fraction of the fiber. f σ is the diameter of the fiber. f0 α represents the normal stress of the CMC material when it is undamaged. f α is the coefficient of thermal expansion of the fiber. c ΔT1 is the coefficient of thermal expansion of CMC material, and ΔT1 is the temperature difference between the preparation of CMC material and cooling to room temperature.

[0059] The elastic modulus of CMC material under different damage rates was calculated using the matrix crack density and stress-strain relationship:

[0060]

[0061] In the formula, E is the elastic modulus of CMC material;

[0062] Establish the mapping function relationship between the thermophysical parameters and mechanical properties of CMC materials after mechanical damage, and realize the solution of the solid-thermal coupling analysis of CMC materials after mechanical damage:

[0063] σ T =E(ε-αΔT1)

[0064] In the formula, σ T α represents the thermal stress on the CMC material, and α is the coefficient of thermal expansion of the CMC material.

[0065] This invention addresses the mechanical damage to CMC (Continuous Metallic Components) high-temperature components after long-term service. It establishes a Representational Virtualization (RVE) model of the CMC material's microscale representative unit cell, considering the stochastic characteristics of mechanical damage. The model incorporates mechanical damage patterns such as matrix cracking, interface layer debonding, and fiber fracture that occur in the CMC material after long-term service, with the spacing between different damage characteristics generated by a random function. Based on this model, axial and radial thermal boundary conditions are applied to obtain the axial and radial thermal conductivity of the CMC material at the microscale. The corresponding elastic modulus is calculated using the CMC material matrix crack density formula and stress-strain relationship. This establishes a mapping relationship between the thermophysical parameters and mechanical performance parameters of the CMC material when mechanical damage occurs, enabling the solution of the solid-thermal coupling analysis of the CMC material after random mechanical damage.

[0066] The following description, in conjunction with embodiments, further illustrates the present invention. This example demonstrates the specific implementation steps of a coherent thermal coupling solution method for CMC materials incorporating a probabilistic model. The model used in this example is as follows: Figure 2 and Figure 3 As shown, the model represents both a basic RVE parameterized model of the CMC material with intact, undamaged microstructure and a basic RVE parameterized model of the CMC material with introduced mechanical damage. The basic RVE parameterized model has a length of L and a width of W, and the width of the matrix crack is l. m The debonding length of the interface layer is l i The width of the fiber break is l f The diameter of the fiber is d f The thickness of the interface layer is d i The volume fraction of the fiber is V fThe detailed dimensions of the basic RVE parameterized model are shown in Table 1. The spacing of mechanical damage in CMC material is generated by a random function of COMSOL.

[0067] Table 1 Detailed Dimensional Parameters of the Basic RVE Parametric Model

[0068]

[0069] First, the dimensional parameters of the RVE model are defined in the global definition of COMSOL to facilitate parametric modeling of the intact model. Next, a random function is selected to randomly introduce the mechanical damage of the CMC material into the intact RVE model. Then, material parameters are assigned and thermal boundary conditions are set. The matrix and interface layer are isotropic materials with thermal conductivity set to 16 and 25 W / (K·m), respectively. The fiber is an anisotropic material with thermal conductivity set to {4, 40, 4} W / (K·m), where the axial thermal conductivity is 40 W / (K·m) and the radial thermal conductivity is 4 W / (K·m). To study and analyze the influence of mechanical damage on the anisotropic thermal conductivity of the CMC material, axial and radial thermal boundary conditions need to be set separately to obtain the axial and radial heat flux densities of the CMC material. Then, the axial and radial thermal conductivity are obtained using the Fourier formula. The axial thermal boundary conditions are set as follows: Two surfaces on the XOZ plane are set as follows: one is a low-temperature surface at 1900K, and the other is a high-temperature surface at 1200K. The remaining four outer surfaces of the RVE model are set as periodic boundary conditions. Similarly, the radial thermal boundary conditions are set as follows: Two surfaces on the XOY plane are set as follows: one is a low-temperature surface at 1900K, and the other is a high-temperature surface at 1200K. The remaining four outer surfaces of the RVE model are set as periodic boundary conditions. Air is used within the mechanical damage area of ​​the CMC material, and air is selected as the material assignment. In mesh generation, to improve computational accuracy while reducing unnecessary computational resource consumption, the heat flux density value on the centerline of the RVE model is used as a reference for mesh independence verification. Simultaneously, due to the small size of the damage feature, mesh refinement is required at the mechanical damage area of ​​the CMC material. Structured meshes are generated for the fibers, interface layer, and mechanical damage; unstructured meshes are generated for the matrix, such as... Figure 4 and Figure 5 As shown.

[0070] Analysis of the heat flux density cloud map of the CMC material after mechanical damage revealed that the damage alters the heat transfer path within the CMC material. Furthermore, a sudden increase in heat flux density occurs at the point of contact between the damaged area and the material itself, indicating that mechanical damage increases the potential high thermal stress zone within the CMC material. In this example calculation, with a 5% damage rate, the axial and radial thermal conductivity of the material were the lowest among all calculation conditions, at 16.2456 W / (m·K) and 10.1733 W / (m·K), respectively, representing decreases of 34.5% and 5.32% compared to the intact, undamaged material. By varying the fiber diameter between 6 and 7 μm, the calculated average axial thermal conductivity was 23.72 W / (m·K) with a standard deviation of 0.9385; the average radial thermal conductivity was 11.34 W / (m·K) with a standard deviation of 0.519.

[0071] In this example, the following two formulas were used to calculate the mechanical property parameters of CMC material. The normal stress received by the material can be calculated by formula (1) matrix crack density, and then the strain of the material at this time can be calculated by formula (2), and the elastic modulus of the material can be calculated.

[0072]

[0073] Where m and σ m D is a statistical parameter. sat This represents the final density at crack saturation. In this example, m = 5, σ m =160MPa,D sat =2.5mm -1 The remaining parameters are shown in Table 2.

[0074] Table 2 CMC Material Parameters

[0075]

[0076] The thermal conductivity and Young's modulus of the material were calculated, and the fitted relationships between the thermal conductivity and Young's modulus functions in the X, Y, and Z directions were obtained, respectively, K. X =0.0401E X +5.5512, K Y =0.0102E Y +6.7896, K Z =0.0616E Z +3.0644.

[0077] CMC material turbine blade simulation calculation model, such as Figure 6As shown, the calculation results indicate that the average blade temperature of a blade with a 5% damage rate is 447.2 K, while the average blade temperature of a healthy blade is 441.6 K, an increase of 1.27%. The maximum stress of a blade with a 5% damage rate is 8.02 MPa, while the maximum stress of a healthy blade is 7.71 MPa, an increase of 4.02%. This is because with the addition of material damage, the thermal conductivity and elastic modulus of the material decrease, leading to a greater likelihood of localized high-temperature and high-stress areas.

[0078] This invention addresses the need for accurate prediction of the temperature field requirements of CMC materials after mechanical damage. Considering the heterogeneous and anisotropic characteristics of CMC materials, traditional thermal analysis methods based on homogeneous metals and those neglecting mechanical damage struggle to reflect the impact of mechanical damage on internal heat transfer, temperature field distribution, and thermal stress distribution. Therefore, it is necessary to develop a coherent thermal solution for CMC materials incorporating a probabilistic model to accurately predict the thermal conductivity, temperature field, and thermal stress of CMC materials after mechanical damage.

[0079] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0080] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0081] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or N executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

Claims

1. A method for solving CMC materials using a coherent thermal-solid coupling approach incorporating a probabilistic model, characterized in that, Includes the following steps: Step 1: Construct a parametric RVE model of the microstructure of the CMC material using the commercial software COMSOL; Step 2: Based on the mechanical damage characteristics of CMC materials, use random functions in COMSOL to randomly introduce the mechanical damage characteristics into the microscopic RVE parameterized model of intact and undamaged CMC materials; Step 3: Apply thermal boundary conditions in the axial and radial directions of the micro-based RVE model respectively, and analyze the effects of different mechanical damages and their characteristics on the axial and radial thermal conductivity of the CMC material after mechanical damage occurs using COMSOL analysis. Step 4: By changing the fiber diameter, the influence of random fiber diameter distribution on the radial and axial thermal conductivity of CMC materials is studied. The damage rate of CMC materials is changed by altering the number of damages in the RVE parameterized model of the microstructure of intact CMC materials. The influence of the damage rate on the axial and radial thermal conductivity of CMC materials is studied and analyzed. The elastic modulus of CMC materials under different damage rates is calculated using the matrix crack density and stress-strain relationship. The mapping function relationship between the thermophysical parameters and mechanical performance parameters of CMC materials after mechanical damage is established, realizing the solution of the solid-thermal coupling analysis of CMC materials after mechanical damage.

2. The method according to claim 1, characterized in that, In step 1, a complete and undamaged parametric micro-foundation RVE model of CMC material is constructed using the commercial software COMSOL. The micro-foundation RVE model is built based on the SEM image of CMC material and includes fibers, interface layer and matrix. The dimensional parameters of the micro-foundation RVE model are assigned values ​​through the defined parameters in COMSOL to achieve parametric modeling.

3. The method according to claim 1, characterized in that, In step 2, the mechanical damage characteristics of CMC material are obtained based on the SEM images of CMC material. A random function is generated in COMSOL, and the damage location is assigned by the generated random function. The mechanical damage characteristics are then introduced into the microscopic RVE parameterized model of the intact and undamaged CMC material.

4. The method according to claim 1, characterized in that, In step 3, the mechanical damage characteristics refer to the location of mechanical damage in the CMC material and the fiber diameter of the CMC material. By generating a random function in COMSOL, the mechanical damage location and fiber diameter of the CMC material are randomly assigned. By setting two different thermal boundary conditions, axial and radial, on the microscopic basic RVE model, the physical field information of the axial temperature field, heat flux density field and radial temperature field of the CMC material after mechanical damage is obtained. The influence of different damage forms on the internal heat transfer of the CMC material is analyzed. The axial thermal conductivity and radial thermal conductivity of the CMC material are calculated using the Fourier formula.

5. The method according to claim 4, characterized in that, In step 3, the axial thermal conductivity and radial thermal conductivity of the CMC material are calculated using Fourier's formula as follows: In the formula, k is the axial thermal conductivity and radial thermal conductivity, q is the heat passing through a unit area cross section per unit time, Δx is the length change value perpendicular to the unit area cross section, and ΔT is the temperature change value perpendicular to the unit area cross section.

6. The method according to claim 1, characterized in that, In step 4, the crack density of the CMC material matrix is ​​calculated as follows: In the formula, D is the matrix crack density, D sat Let σ be the final density when the crack reaches saturation, and σ be the stress on the CMC material. m Both m and are statistical parameters; The stress-strain relationship is: In the formula, ε is the strain of the CMC material, and E f V is the fiber elastic modulus, L is the matrix crack spacing, and V is the fiber elastic modulus. f d is the volume fraction of the fiber, d is the debonding length of the CMC material interface layer, and r is the volume fraction of the fiber. f σ is the diameter of the fiber. f0 α represents the normal stress of the CMC material when it is undamaged. f α is the coefficient of thermal expansion of the fiber. c ΔT1 is the coefficient of thermal expansion of CMC material, and ΔT1 is the temperature difference between the preparation of CMC material and cooling to room temperature. The elastic modulus of CMC material under different damage rates was calculated using the matrix crack density and stress-strain relationship: In the formula, E is the elastic modulus of CMC material; Establish the mapping function relationship between the thermophysical parameters and mechanical properties of CMC materials after mechanical damage, and realize the solution of the solid-thermal coupling analysis of CMC materials after mechanical damage: s T =E(ε-αΔT1) In the formula, σ T α represents the thermal stress on the CMC material, and α is the coefficient of thermal expansion of the CMC material.

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