Dynamic modeling and parameter optimization method for ceramic matrix composite and metal connection structure

Abstract

The invention discloses a dynamic modeling and parameter optimization method for a ceramic matrix composite and a metal connection structure. The dynamic modeling and parameter optimization method comprises the following steps: constructing a dynamic model of the CMC / metal connection structure comprising thin layer units; determining the pressure distribution of the thin layer unit by adopting a shape function interpolation method; parameters in the theoretical function relational expression between the thin layer unit material parameters and the interface pressure are optimized, and a function relational expression between the thin layer unit elastic parameters and the joint surface pressure is constructed; and establishing a dynamic model of the CMC / metal connection structure under different temperatures and different pre-tightening forces, and calculating the inherent frequency of the CMC / metal connection structure under different pre-tightening forces and temperatures through a modal analysis method. According to the method, a dynamic model of the CMC / metal connection structure which comprehensively considers high-temperature pre-tightening relaxation, metal material high-temperature performance degradation and CMC material nonlinear influence under the pre-tightening force is established, so that effective calculation of the inherent frequency of the connection structure under different pre-tightening force and different temperature conditions is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of dynamic modeling of composite material connection structures, and in particular to a dynamic modeling and parameter optimization method for a ceramic-based composite material and metal connection structure. Background Art

[0002] Ceramic matrix composites (CMCs) are ideal materials for the hot end components of new-generation aircraft engines due to their high specific strength, high specific modulus, corrosion resistance, and excellent high-temperature performance. In practical applications, CMCs often need to be connected to metal structures, among which bolted connections are widely used due to their high reliability and removability. For example, the CMC flame tube in the combustion chamber is bolted to the metal support structure and is subjected to vibration loads caused by non-uniform airflow during service. When the vibration excitation frequency coincides with the natural frequency of the structure, resonance may be triggered, resulting in excessive dynamic stress and structural damage. In addition, the modal parameters of the structure are the basis for frequency-domain dynamic response analysis, so accurately predicting the dynamic characteristics of the connected structure is crucial.

[0003] In CMC / metal bolted connections, bolt preload compresses the connected components. However, because the connection interface is not completely rigid, the overall dynamic behavior of the structure depends largely on the contact characteristics of the mating surfaces. Therefore, accurately modeling the mechanical behavior of the connection interface is key to analyzing the dynamic characteristics of the connection structure.

[0004] At present, the main methods for joint modeling include the binding connection method, the spring-damper unit method, and the thin layer unit method. The binding method assumes that the connection is completely rigid and cannot consider the influence of preload; the spring-damper unit method simulates the interface through discrete springs, but it is difficult to determine the spring parameters and ignores the degree of freedom coupling (An Weiwei, Guo Lei, Gong Zhuorong. Dynamic stiffness identification method of bolted joint based on modal experiment [J]. Mechanical Design and Manufacturing, 2015(02):1-3+7.); the thin layer unit method introduces a thin layer of material at the connection interface and simulates the contact state under different preloads by adjusting its mechanical parameters. It has been widely proven to be able to effectively reflect the influence of preload. The material models of thin layer units can be divided into three categories: isotropic, orthotropic, and gradient materials. Among them, the gradient material model assumes that the material parameters are related to the contact pressure, can consider the non-uniformity of pressure distribution, and is closer to the actual working conditions.

[0005] However, existing studies usually calculate the interface pressure distribution based on macroscopic models (

[143] Sun Zhiyong. Research on the dynamic characteristics of bolted joints based on virtual materials [D]. Dalian University of Technology, 2018.), which fails to consider the effect of the heterogeneity of the CMC microstructure on the local contact pressure, resulting in large modal prediction errors. Therefore, it is necessary to develop a connection structure dynamic modeling method that can integrate the CMC microstructure characteristics to improve the accuracy of dynamic characteristics analysis. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for dynamic modeling and parameter optimization of ceramic-based composite and metal connection structures. A dynamic model of a CMC / metal connection structure is established that comprehensively considers high-temperature preload relaxation, high-temperature performance degradation of metal materials, and the nonlinear effects of CMC materials under preload. This allows for the effective calculation of the natural frequency of the connection structure under different preload forces and different temperature conditions.

[0007] In order to achieve the above technical objectives, the technical solution adopted by the present invention is:

[0008] A method for dynamic modeling and parameter optimization of a ceramic matrix composite material and metal connection structure, comprising the following steps:

[0009] S1, based on the macro-micro integrated model of the CMC / metal connection structure, obtains the pressure distribution of the bonding surface under different preloads and temperatures. The bonding surface refers to the contact surface between the CMC connected part and the metal connected part. The CMC / metal connection structure includes the CMC connected part and the metal connected part.

[0010] S2, based on the full macroscopic model of the CMC / metal connection structure, thin-layer units are established between the CMC connected parts and the metal connected parts to construct a dynamic model of the CMC / metal connection structure including thin-layer units;

[0011] S3, based on the pressure distribution of the bonding surface calculated in step S1 and the dynamic model of the CMC / metal connection structure established in step S2, the pressure distribution of the thin layer unit is determined using a shape function interpolation method;

[0012] S4, determine the theoretical functional relationship between the thin layer unit material parameters and the interface pressure;

[0013] S5, solving the natural frequencies of the CMC / metal connection structure under different temperature and preload conditions through modal analysis, obtaining simulation results of the natural frequencies; and establishing a proxy model between the natural frequencies of the CMC / metal connection structure and the theoretical functional relationship in step S4;

[0014] S6: Conduct modal tests on CMC / metal connections under different temperatures and preload conditions to obtain test results of natural frequencies.

[0015] S7, comparing the simulation results of the natural frequency predicted based on the surrogate model with the test results in step S6, optimizing the parameters in the theoretical functional relationship using a genetic algorithm, and constructing a functional relationship between the elastic parameters of the thin layer element and the interface pressure;

[0016] In step S8, the calculated results of the thin-layer unit pressure at different preload forces and temperatures are substituted into the functional relationship constructed in step S7 to obtain the corresponding thin-layer unit material parameter distribution; the CMC material parameters of the dynamic model in step S2 are adjusted through the coordinate relationship, a dynamic model of the CMC / metal connection structure at different temperatures and preload forces is established, and the natural frequencies of the CMC / metal connection structure at different preload forces and temperatures are calculated using the modal analysis method.

[0017] Furthermore, in step S1, the process of constructing the macro-micro integrated model of the CMC connection structure includes the following steps:

[0018] A mesoscopic model is established in the stress concentration area or overlap area of ​​the CMC perforated plate, and a macroscopic model is established in the area with uniform stress distribution. The interface between the macroscopic and mesoscopic models is located at the cross section with small porosity in the mesoscopic model and an integrated mesh is performed. Then, a macroscopic model is established for the metal fasteners and connected parts to construct a macro- and mesoscopic integrated model of the CMC / metal connection structure.

[0019] Furthermore, in step S1, the process of obtaining the pressure distribution of the bonding surface under different preload forces and different temperatures includes the following steps:

[0020] The initial elastic parameters and constitutive behaviors of yarn and braided CMC were substituted into the microscopic model and macroscopic model of the CMC connected parts, respectively. At room temperature, an initial preload at room temperature was applied to the macro-microscopic integrated model of the CMC / metal connection structure to obtain the pressure distribution of the bonding surface at room temperature. At high temperature, the initial preload at room temperature and the high-temperature preload were applied successively to obtain the pressure distribution of the bonding surface at high temperature.

[0021] Step S2 further comprises:

[0022] Based on the full macroscopic model of the CMC / metal connection structure, the metal fasteners and holes in the connected parts are removed, and a thin layer unit structure with a thickness of 1 mm is established between the CMC connected parts and the metal connected parts. The dynamic model of the CMC / metal connection structure is established, and the common node method is used to mesh the different components in the dynamic model of the CMC / metal connection structure.

[0023] Step S3 further comprises:

[0024] Based on the pressure distribution of the bonding surface under different preloads and temperatures obtained in step S1, relevant information of the bonding surface is extracted, including contact elements, node coordinates, pressure values, and coordinates of the center points of the contact elements; based on the dynamic model of the CMC / metal connection structure obtained in step S2, coordinate information of the center points of the thin layer elements is obtained;

[0025] Based on the shape function interpolation method in finite element analysis, each node in the contact element is processed, and the pressure value corresponding to the center coordinate of the thin layer element is calculated by weighted superposition of the node pressure value through shape function.

[0026] Step S4 further comprises:

[0027] Assume that the elastic modulus of the thin layer element is E bc With contact pressure P n The following relationship is satisfied:

[0028]

[0029] Among them, the coefficient a1 and the exponent b1 are determined by comparison with the experiment; the conversion formula obtains the functional relationship between the thin layer unit material parameters and the interface pressure:

[0030]

[0031] Among them, E max It represents the elastic modulus corresponding to the maximum pressure of the thin layer unit at different preloads and temperatures, P n / P n_max It represents the calculation result of normalizing the thin layer unit pressure based on the maximum value, and the index b1 represents the fitting index.

[0032] Step S5 further comprises:

[0033] The Latin hypercube sampling method is used to sample the coefficients and exponents in the functional relationship between the thin-layer element material parameters and the interface pressure in the parameter space. For each sample point, the distribution of the thin-layer element material parameters under different temperature and preload conditions is calculated. The natural frequency of the CMC / metal connection structure is solved through modal analysis, and the simulation results of the natural frequency are obtained.

[0034] Construct a proxy model based on the Kriging method and establish a mapping relationship between the natural frequency simulation results and the coefficient a1 and exponent b1;

[0035] The proxy model is trained and validated using the sampled data until the root mean square error of the proxy model is no greater than the preset error threshold.

[0036] Furthermore, in step S7, the fitness function used by the genetic algorithm is the error expression between the simulation result of the natural frequency predicted by the agent model and the test result in step S6, which is expressed as:

[0037]

[0038] Among them, f exp_i and f ga_iare the experimental value and the predicted result of the surrogate model of the first-order natural frequency under the i-th preload and temperature combination conditions, n represents the total number of combination conditions, w i Represents the weighting coefficient of the i-th preload and temperature combination condition;

[0039] The value range of the parameter to be identified in the theoretical function relationship is the value range of the sample points during Latin hypercube sampling.

[0040] Step S8 further includes:

[0041] Substituting the calculated results of the thin layer unit pressure at different preload forces and temperatures into the functional relationship constructed in step S7, the corresponding thin layer unit material parameter distribution is obtained;

[0042] Based on a full macroscopic model of the CMC / metal connection structure and a progressive damage analysis method, the nonlinear constitutive damage behavior of the CMC material under the initial state at room temperature and the residual preload at high temperature is obtained. The CMC material parameters in the dynamic model of the CMC / metal connection structure are adjusted through coordinate correspondence. At the same time, the metal material parameters in the dynamic model of the CMC / metal connection structure are adjusted according to the temperature. Finally, a dynamic model of the CMC / metal connection structure is established, considering the influence of temperature and preload on the material parameters of the connected structure and the state of the bonding surface. Based on modal analysis, the natural frequencies of the CMC / metal connection structure under different preloads and temperatures are calculated.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] The dynamic modeling and parameter optimization method of the ceramic matrix composite material and metal connection structure of the present invention can effectively describe the influence of the non-uniformity of the CMC microstructure on the pressure of the bonding surface based on the macro-micro integrated model of the CMC connection structure, thereby obtaining the pressure distribution of the bonding surface under different temperatures and torques. In addition, the present invention establishes a CMC microstructure dynamic model containing thin layer units, and combines the shape function interpolation method with the non-uniform pressure distribution of the bonding surface to further optimize the pressure distribution calculation of the thin layer units. Through the parameter identification method, the distribution of the material parameters of the thin layer units under different preload forces and different temperatures was successfully determined. Finally, the present invention establishes a CMC connection structure dynamic model that comprehensively considers the high-temperature preload relaxation, high-temperature performance degradation of metal materials, and the nonlinear effects of CMC materials under preload forces, thereby realizing the effective calculation of the natural frequency of the connection structure under different preload forces and different temperature conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 Schematic diagram of the macro-micro integrated model of the CMC / metal connection structure;

[0046] Figure 2Schematic diagram of pressure distribution on the bonding surface of CMC / metal connection structure;

[0047] Figure 3 Schematic diagram of pressure distribution on the joint surface of CMC / metal connection structure under different torques and temperatures;

[0048] Figure 4 Schematic diagram of the dynamic model of CMC / metal joint structure including thin layer elements;

[0049] Figure 5 Schematic diagram of pressure distribution of thin layer unit under different preload and temperature;

[0050] Figure 6 is the distribution diagram of coefficient and index sample points;

[0051] Figure 7 Schematic diagram of the first-order natural frequency proxy model fitting and prediction results for the CMC / metal connection structure;

[0052] Figure 8 Schematic diagram of the first-order natural frequency test results of the CMC / metal connection structure;

[0053] Figure 9 It is a flow chart of the steps of the present invention. DETAILED DESCRIPTION

[0054] The embodiments of the present invention are described in further detail below with reference to the accompanying drawings.

[0055] The present invention discloses a method for dynamic modeling and parameter optimization of a ceramic matrix composite material and a metal connection structure. Figure 9 As shown, the method includes the following steps:

[0056] S1, based on the macro-micro integrated model of the CMC / metal connection structure, obtains the pressure distribution of the bonding surface under different preloads and temperatures. The bonding surface refers to the contact surface between the CMC connected part and the metal connected part. The CMC / metal connection structure includes the CMC connected part and the metal connected part.

[0057] S2, based on the full macroscopic model of the CMC / metal connection structure, thin-layer units are established between the CMC connected parts and the metal connected parts to construct a dynamic model of the CMC / metal connection structure including thin-layer units;

[0058] S3, based on the pressure distribution of the bonding surface calculated in step S1 and the dynamic model of the CMC / metal connection structure established in step S2, the pressure distribution of the thin layer unit is determined using a shape function interpolation method;

[0059] S4, determine the theoretical functional relationship between the thin layer unit material parameters and the interface pressure;

[0060] S5, solving the natural frequencies of the CMC / metal connection structure under different temperature and preload conditions through modal analysis, obtaining simulation results of the natural frequencies; and establishing a proxy model between the natural frequencies of the CMC / metal connection structure and the theoretical functional relationship in step S4;

[0061] S6: Conduct modal tests on CMC / metal connections under different temperatures and preload conditions to obtain test results of natural frequencies.

[0062] S7, comparing the simulation results of the natural frequency predicted based on the surrogate model with the test results in step S6, optimizing the parameters in the theoretical functional relationship using a genetic algorithm, and constructing a functional relationship between the elastic parameters of the thin layer element and the interface pressure;

[0063] In step S8, the calculated results of the thin-layer unit pressure at different preload forces and temperatures are substituted into the functional relationship constructed in step S7 to obtain the corresponding thin-layer unit material parameter distribution; the CMC material parameters of the dynamic model in step S2 are adjusted through the coordinate relationship, a dynamic model of the CMC / metal connection structure at different temperatures and preload forces is established, and the natural frequencies of the CMC / metal connection structure at different preload forces and temperatures are calculated using the modal analysis method.

[0064] (1) Establish a macro- and micro-integrated model of the CMC / metal connection structure. For the CMC connected components, a macro- and micro-integrated model is established. Specifically, a micro-model is established in the stress concentration area or overlap area of ​​the CMC perforated plate, and a macro-model is established in the area with uniform stress distribution. The interface between the macro- and micro-models is located on a cross-section with a small porosity in the micro-model, and an integrated mesh is performed. Macro-models are established for the metal fasteners and connected components, and finally, a macro- and micro-integrated model of the CMC / metal connection structure is established.

[0065] Based on an integrated macro- and micro-scale model of the CMC / metal connection structure, the pressure distribution of the interface under different preloads and temperatures was obtained. The initial elastic parameters and constitutive behavior of the yarn and braided CMC were incorporated into the micro- and macro-scale models of the CMC connected components, respectively. At room temperature, an initial preload was applied to obtain the pressure distribution of the interface at room temperature. At high temperatures, the initial and high-temperature preloads were applied sequentially to obtain the pressure distribution of the interface at high temperatures. The interface specifically refers to the contact surface between the CMC connected component and the metal connected component.

[0066] In this example, the macro-micro integrated model of the CMC / metal connection structure is shown in the attached figure. Figure 1As shown in Figure 2 . The macro- and micro-model interface is located at the center cross section of the weft yarn in the micro-model. This region has the lowest porosity, effectively reducing stress concentration caused by geometric discontinuities at the interface. The micro-model is used throughout the entire connection area to ensure accurate calculation of the pressure distribution at the interface. The anisotropic material parameters of the yarn and braided CMC are shown in Tables 1 and 2. The residual preload data at room temperature and 600°C corresponding to different initial torques (5, 10, and 15 N·m) are shown in Table 3.

[0067] Table 1 Initial elastic parameters of yarn

[0068]

[0069] Table 2 Initial elastic parameters of braided CMC

[0070]

[0071] Table 3 Residual preload of CMC / metal connection structure at room temperature and 600℃

[0072]

[0073]

[0074] In this example, the pressure distribution on the joint surface of the connection structure under the action of preload is shown in the attached figure. Figure 2 As shown. Figure 3 The pressure distribution under different torque and temperature conditions is further demonstrated. The analysis shows that at the same temperature, the interface pressure amplitude increases with the initial preload; when the temperature rises, the interface pressure tends to decrease due to the preload relaxation effect.

[0075] (2) Establish a dynamic model of the CMC / metal connection structure including thin-layer units. Based on the full macroscopic model of the CMC / metal connection structure, the holes in the fasteners and the connected parts are removed, and a thin-layer structure with a thickness of 1 mm is established between the CMC connected parts and the metal connected parts, thereby establishing a dynamic model of the CMC / metal connection structure. The different components of the connection structure are meshed in the form of common nodes to meet the requirements of linear modal analysis and calculation. In this example, the dynamic model of the connection structure including thin-layer units is shown in the attached figure. Figure 4 shown.

[0076] (3) Use the shape function interpolation method to determine the pressure distribution of the thin layer unit. For the macro-micro integrated model of the CMC / metal connection structure, it is necessary to extract the relevant information of the contact surface unit, including the contact unit, node coordinates, pressure value and the coordinates of the center point of the contact unit, and at the same time obtain the coordinate information of the center point of the thin layer unit. Based on the shape function interpolation method in finite element analysis, the pressure value corresponding to the center coordinate of the thin layer unit is calculated. For triangular contact units, the area method can be used to simplify the calculation process of the shape function. Specifically, the shape function interpolation coefficients of any point in the three-node and six-node triangular units are shown in formulas (1) and (2), respectively. By weighting the shape function and superimposing the node pressure values, the pressure distribution corresponding to the thin layer unit can be obtained.

[0077]

[0078] Among them, i, j, m are the three corner nodes of the triangle, i', j', m' represent the middle nodes on the edge corresponding to the corner nodes i, j, m, A ijm represents the area of ​​the triangle, A i Represents the area of ​​any point in the triangle and the corner nodes j and m. Similarly, A j A represents the area of ​​any point in the triangle and the corner nodes i and m. m represents the area formed by any point in the triangle and the corner nodes i and j, L i ,L j ,L m Indicates the interpolation coefficient of the corresponding nodes of the three-node triangle, N i ,N j ,N m ,N i' ,N j' ,N m' Indicates the interpolation coefficients of the corresponding nodes of the six-node triangle.

[0079] (4) Determine the functional relationship between the thin layer unit material parameters and the interface pressure. The same functional relationship is used between the thin layer unit material parameters and the interface pressure at different temperatures and torques. Assume that the elastic modulus of the thin layer unit E bc With contact pressure P n The relationship between them satisfies the relationship shown in formula (3), where the coefficient a1 and the exponent b1 are determined by comparison with the test. In order to facilitate the determination of the value range of the coefficient and the exponent, formula (3) is further transformed into the relationship shown in formula (4). max represents the elastic modulus corresponding to the maximum pressure of the thin layer unit at different torques and temperatures in step (1), P n / P n_max It means that the thin layer unit pressure is normalized based on the maximum value, and the index represents the corresponding relationship between the ratio of the elastic modulus of the thin layer unit and the pressure ratio.

[0080] In this example, E max The value range is 0.01-20GPa, and the value range of b1 is 0.1-1.2.

[0081]

[0082]

[0083] Figure 5 Schematic diagram of pressure distribution of thin layer units under different preloads and temperatures.

[0084] (5) The Latin hypercube sampling (LHS) method is used to sample the parameter space of the coefficients and exponents in formula (4). For each sample point, the parameter distribution of the thin-layer unit material under different temperature and torque conditions is calculated, and the natural frequency of the connection structure is solved by modal analysis. A proxy model is constructed based on the Kriging method, and a mapping relationship between the natural frequency simulation results and the function parameters (coefficients and exponents) is established. 95% of the sample data is used as the training set, and the remaining 5% is used as the test set, and an error threshold of 1% is set. The accuracy of the proxy model is verified by calculating the root mean square error (RMSE) of the training set and the test set. If the RMSE exceeds the threshold, the number of sampling points is increased to improve the reliability of the model.

[0085] In this example, the coefficient P n_max The LHS sampling distribution of the index b1 is shown in the attached figure. Figure 6 As shown in the figure, the sample points are evenly distributed in the parameter space. Figure 7 As shown in the figure, the prediction results of the surrogate model are highly consistent with the modal analysis results: the maximum fitting error of the training set is 0.79%, and the maximum prediction error of the test set is 0.47%, both of which are lower than the error threshold of 1%, indicating that the surrogate model has good accuracy and generalization ability, and can effectively support subsequent parameter identification work.

[0086] (6) Obtain the natural frequency response of the connection structure at room temperature and high temperature (such as 600°C) through frequency sweep test. Figure 8 As shown in the figure, the test results show that: at a fixed temperature, the natural frequency first increases and then decreases with the increase of torque; under the same torque conditions, the increase in temperature will lead to a decrease in the natural frequency.

[0087] (7) Compare the prediction results of the proxy model with the test data, and use the genetic algorithm to optimize the functional relationship between the elastic parameters of the thin layer unit and the interface pressure. As shown in formula (5), the relative error of the natural frequency is used as the fitness function:

[0088]

[0089] Among them, f exp_i and f ga_i They are the experimental value and the proxy model prediction result of the first-order natural frequency at a certain torque and temperature, i represents the combination of different torques and different temperatures, n represents the number of combinations, and w i represents the weighting coefficient. The range of the parameters in the functional relationship to be identified is the range of the sample points during LHS sampling. Ultimately, the functional relationship between the thin layer element material parameters and pressure can be identified.

[0090] In this example, the coefficient w i The average value is 1, and n is 6, representing six different preload and temperature combinations. The genetic algorithm parameters are selected as follows: 500 initial sample points, a coefficient of variation of 0.2, and a crossover probability of 0.4. The range of values ​​for the parameter to be identified corresponds to the range of values ​​for the sample points during LHS sampling. The test results with an initial torque of 5 N·m and an ambient temperature of 600°C (abbreviated as: 5 N·m-600°C) serve as the test set, while the other test results serve as the training set. Ultimately, the coefficient and exponent identification results for the thin-layer element elastic modulus calculation function are 4.312 GPa and 0.534, respectively.

[0091] (8) Substitute the calculated results of the thin-layer unit pressure under different torques and temperatures into the formula (3) identified in step (7) to obtain the corresponding thin-layer unit material parameter distribution. Based on the macroscopic model of the CMC / metal connection structure and the progressive damage analysis method, the nonlinear constitutive damage behavior of the CMC material under the initial state at room temperature and the residual preload at high temperature is obtained, and the CMC material parameters in the CMC / metal dynamic model are adjusted through the coordinate correspondence. At the same time, considering the influence of temperature on the metal elastic modulus, a dynamic model of the CMC / metal connection structure under different torque and temperature conditions is established, and the natural frequency of the connection structure under different torque and temperature conditions is calculated through modal analysis.

[0092] In this example, the natural frequency identification and prediction results are shown in Table 4. It can be seen that the calculation errors are small under all operating conditions, with the maximum identification error being 0.13 Hz and the maximum prediction error being 0.26 Hz. Therefore, the proposed method for connecting structural dynamic modeling and parameter identification, which considers the heterogeneous characteristics of the CMC microstructure, has high accuracy and engineering applicability.

[0093] Table 4 Identification and prediction results of the first-order natural frequency of CMC / metal connection structure

[0094]

[0095] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application.

[0096] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. A method for dynamic modeling and parameter optimization of a ceramic matrix composite material and metal connection structure, characterized in that: The method comprises the following steps: S1, based on the macro-micro integrated model of the CMC / metal connection structure, obtains the pressure distribution of the bonding surface under different preloads and temperatures. The bonding surface refers to the contact surface between the CMC connected part and the metal connected part. The CMC / metal connection structure includes the CMC connected part and the metal connected part. S2, based on the full macroscopic model of the CMC / metal connection structure, thin-layer units are established between the CMC connected parts and the metal connected parts to construct a dynamic model of the CMC / metal connection structure including thin-layer units; S3, based on the pressure distribution of the bonding surface calculated in step S1 and the dynamic model of the CMC / metal connection structure established in step S2, the pressure distribution of the thin layer unit is determined using a shape function interpolation method; S4, determine the theoretical functional relationship between the thin layer unit material parameters and the interface pressure; S5, solving the natural frequencies of the CMC / metal connection structure under different temperature and preload conditions through modal analysis, obtaining simulation results of the natural frequencies; and establishing a proxy model between the natural frequencies of the CMC / metal connection structure and the theoretical functional relationship in step S4; S6: Conduct modal tests on CMC / metal connections under different temperatures and preload conditions to obtain test results of natural frequencies. S7, comparing the simulation results of the natural frequency predicted based on the surrogate model with the test results in step S6, optimizing the parameters in the theoretical functional relationship using a genetic algorithm, and constructing a functional relationship between the elastic parameters of the thin layer element and the interface pressure; In step S8, the calculated results of the thin-layer unit pressure at different preload forces and temperatures are substituted into the functional relationship constructed in step S7 to obtain the corresponding thin-layer unit material parameter distribution; the CMC material parameters of the dynamic model in step S2 are adjusted through the coordinate relationship, a dynamic model of the CMC / metal connection structure at different temperatures and preload forces is established, and the natural frequencies of the CMC / metal connection structure at different preload forces and temperatures are calculated using the modal analysis method.

2. The method for dynamic modeling and parameter optimization of a ceramic matrix composite material and metal connection structure according to claim 1, characterized in that: In step S1, the process of constructing the macro-micro integrated model of the CMC connection structure includes the following steps: A mesoscopic model is established in the stress concentration area or overlap area of ​​the CMC perforated plate, and a macroscopic model is established in the area with uniform stress distribution. The interface between the macroscopic and mesoscopic models is located at the cross section with small porosity in the mesoscopic model and an integrated mesh is performed. Then, a macroscopic model is established for the metal fasteners and connected parts to construct a macro- and mesoscopic integrated model of the CMC / metal connection structure.

3. The method for dynamic modeling and parameter optimization of a ceramic matrix composite material and metal connection structure according to claim 1, characterized in that: In step S1, the process of obtaining the pressure distribution of the bonding surface under different preload forces and different temperatures includes the following steps: The initial elastic parameters and constitutive behaviors of yarn and braided CMC were substituted into the microscopic model and macroscopic model of the CMC connected parts, respectively. At room temperature, an initial preload at room temperature was applied to the macro-microscopic integrated model of the CMC / metal connection structure to obtain the pressure distribution of the bonding surface at room temperature. At high temperature, the initial preload at room temperature and the high-temperature preload were applied successively to obtain the pressure distribution of the bonding surface at high temperature.

4. The method for dynamic modeling and parameter optimization of a ceramic matrix composite material and metal connection structure according to claim 1, characterized in that: Step S2 further comprises: Based on the full macroscopic model of the CMC / metal connection structure, the metal fasteners and holes in the connected parts are removed, and a thin layer unit structure with a thickness of 1 mm is established between the CMC connected parts and the metal connected parts. The dynamic model of the CMC / metal connection structure is established, and the common node method is used to mesh the different components in the dynamic model of the CMC / metal connection structure.

5. The method for dynamic modeling and parameter optimization of a ceramic matrix composite material and metal connection structure according to claim 1, characterized in that: Step S3 further comprises: Based on the pressure distribution of the bonding surface under different preloads and temperatures obtained in step S1, relevant information of the bonding surface is extracted, including contact elements, node coordinates, pressure values, and coordinates of the center points of the contact elements; based on the dynamic model of the CMC / metal connection structure obtained in step S2, coordinate information of the center points of the thin layer elements is obtained; Based on the shape function interpolation method in finite element analysis, each node in the contact element is processed, and the pressure value corresponding to the center coordinate of the thin layer element is calculated by weighted superposition of the node pressure value through shape function.

6. The method for dynamic modeling and parameter optimization of a ceramic matrix composite material and metal connection structure according to claim 1, characterized in that: Step S4 further comprises: Assume that the elastic modulus of the thin layer element is E bc With contact pressure P n The following relationship is satisfied: Among them, the coefficient a1 and the exponent b1 are determined by comparison with the experiment; the conversion formula obtains the functional relationship between the thin layer unit material parameters and the interface pressure: Among them, E max It represents the elastic modulus corresponding to the maximum pressure of the thin layer unit at different preloads and temperatures, P n / P n_max It represents the calculation result of normalizing the thin layer unit pressure based on the maximum value, and the index b1 represents the fitting index.

7. The method for dynamic modeling and parameter optimization of a ceramic matrix composite material and metal connection structure according to claim 6, characterized in that: Step S5 further comprises: The Latin hypercube sampling method is used to sample the coefficients and exponents in the functional relationship between the thin-layer element material parameters and the interface pressure in the parameter space. For each sample point, the distribution of the thin-layer element material parameters under different temperature and preload conditions is calculated. The natural frequency of the CMC / metal connection structure is solved through modal analysis, and the simulation results of the natural frequency are obtained. Construct a proxy model based on the Kriging method and establish a mapping relationship between the natural frequency simulation results and the coefficient a1 and exponent b1; The proxy model is trained and validated using the sampled data until the root mean square error of the proxy model is no greater than the preset error threshold.

8. The method for dynamic modeling and parameter optimization of a ceramic matrix composite material and metal connection structure according to claim 1, characterized in that: In step S7, the fitness function used by the genetic algorithm is the error expression between the simulation result of the natural frequency predicted by the agent model and the test result in step S6, which is expressed as: Among them, f exp_i and f ga_i are the experimental value and the predicted result of the surrogate model of the first-order natural frequency under the i-th preload and temperature combination conditions, n represents the total number of combination conditions, w i Represents the weighting coefficient of the i-th preload and temperature combination condition; The value range of the parameter to be identified in the theoretical function relationship is the value range of the sample points during Latin hypercube sampling.

9. The method for dynamic modeling and parameter optimization of a ceramic matrix composite material and metal connection structure according to claim 1, characterized in that: Step S8 further includes: Substituting the calculated results of the thin layer unit pressure at different preload forces and temperatures into the functional relationship constructed in step S7, the corresponding thin layer unit material parameter distribution is obtained; Based on a full macroscopic model of the CMC / metal joint structure and a progressive damage analysis method, the nonlinear constitutive damage behavior of the CMC material under the initial state at room temperature and the residual preload at high temperature is determined. The CMC material parameters in the dynamic model of the CMC / metal joint structure are adjusted using coordinate correspondences. Simultaneously, the metal material parameters in the dynamic model of the CMC / metal joint structure are adjusted according to temperature. Finally, a dynamic model of the CMC / metal joint structure is established, taking into account the effects of temperature and preload on the material parameters of the connected structure and the state of the bonding interface. Based on modal analysis, the natural frequencies of the CMC / metal connection structure under different preload forces and temperatures are calculated.

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