A ceramic matrix composite gas-solid coupling vibration simulation method

Abstract

The application discloses a kind of ceramic matrix composite gas-solid coupling vibration simulation methods, comprising: the multiscale finite element model of ceramic matrix material is established;The load of gas flow field is calculated using computational fluid dynamics method, and the physical quantity between gas-solid interface is accurately mapped and transferred by radial basis function interpolation function;The stress-strain distribution in solid domain is solved by computational structural dynamics method, and closed loop feedback is formed in combination with fluid load, and the two-way coupling of fluid domain and solid domain is carried out;The stress-strain hysteresis behavior model of ceramic matrix material is constructed, and the vibration response under arbitrary stress path is calculated;The displacement of solid node is fed back to CFD fluid model, and the position of fluid node is updated, and dynamic gas-solid coupling vibration is calculated, and the synchronous iteration in two domains is maintained.The application overcomes the numerical instability caused by material stiffness mutation and nonlinear hysteresis behavior in traditional numerical simulation, and has high efficiency and robustness.

Description

Technical Field

[0001] The present invention relates to the technical field of vibration simulation of ceramic-based materials in a high-temperature flow field environment, and in particular to a gas-solid coupling vibration simulation method for ceramic-based composite materials, which is suitable for dynamic response analysis of ceramic-based structures (such as cantilever beams). Background Art

[0002] Under high-temperature conditions, the mechanical properties of ceramic matrix composites (CMCs) exhibit significant nonlinearity, accompanied by complex fluid-structure interaction (FSI) phenomena. FSI not only affects the material's vibration behavior but can also cause structural failure. However, existing FSI computational methods often struggle to achieve both accuracy and stability when dealing with the complex nonlinear behavior of CMCs, making it difficult to provide reliable vibration predictions.

[0003] In existing technologies, such as the staggered iterative coupling technique and the Newmark method, although they can handle fluid-structure coupling problems, most methods use linear material models and ignore the nonlinear behavior of materials during loading and unloading. In existing studies, although fluid-structure coupling models have been introduced when calculating the vibration response of ceramic-based materials, the following limitations still exist: (1) Ignoring hysteresis behavior: Most studies are limited to the linear characteristics of the material and fail to effectively describe the nonlinear hysteresis effect, which is crucial in the vibration and fatigue analysis of ceramic-based materials. (2) Poor computational robustness: Traditional methods are prone to cumulative errors in multiple loading and unloading cycles, resulting in unstable numerical calculations and an inability to accurately predict dynamic responses under complex working conditions.

[0004] Ceramic matrix composites (CMCs) are composite materials composed of a ceramic matrix and fiber reinforcements. They are widely used in the aerospace industry due to their exceptional properties, including high specific strength, high specific modulus, corrosion resistance, and high-temperature resistance. Compared to traditional high-temperature alloys, CMCs not only have a lower density but also exhibit higher modulus and strength at high temperatures, offering enhanced resistance to ablation and thermal shock. Therefore, CMCs are considered an ideal alternative to high-temperature alloys for manufacturing hot-end components in aircraft engines.

[0005] However, the complex mechanical properties of ceramic matrix composites (CMCs), such as vibration, fatigue, and strength, pose significant challenges to performance prediction. In particular, under extreme environments such as high temperature, high pressure, and gas-solid coupling, these materials are often subjected to complex stress conditions and frequent loading and unloading cycles, exhibiting complex variable stiffness and hysteresis. Therefore, accurately describing the mechanical behavior of these materials under these complex conditions is crucial for predicting their performance in practical applications.

[0006] Current research on constitutive models for ceramic matrix composites faces two major challenges: (1) Accurate description of damage modes: CMCs are prone to microcracks under high temperature and high pressure environments, and the materials exhibit nonlinear properties. Accurately capturing the damage modes of materials is a key challenge in constitutive modeling. (2) Nonlinear loading and unloading behavior: Under complex stress conditions, ceramic matrix materials exhibit significant nonlinear stress-strain hysteresis behavior. Existing modeling methods are often unable to adequately address this dynamic nonlinear response.

[0007] In order to solve these problems, it is urgent to develop a vibration simulation method that can effectively handle the variable stiffness and hysteresis behavior of materials, especially in the dynamic response calculation under gas-solid coupling, to ensure the accuracy and stability of the calculation. Summary of the Invention

[0008] The present invention aims to address the shortcomings of the existing technology in the calculation of fluid-solid coupling response of ceramic matrix composites (CMCs) under high temperature and high pressure environments, which makes it difficult to accurately describe complex mechanical behaviors and nonlinear phenomena. In particular, the present invention proposes a gas-solid coupling vibration simulation method for ceramic matrix composites, combined with a dynamic solution model of fluid-solid coupling, to provide an efficient and accurate solution for predicting the vibration behavior of ceramic matrix composites.

[0009] In order to achieve the above technical objectives, the technical solution adopted by the present invention is:

[0010] A gas-solid coupled vibration simulation method for ceramic matrix composite materials, the simulation method comprising the following steps:

[0011] S1, based on ceramic matrix composites under high temperature and high pressure environment, comprehensively consider the mechanical properties and thermodynamic characteristics of ceramic matrix composites, and establish a multi-scale finite element model of ceramic matrix materials;

[0012] S2, by using the polynomial fitting method, a stress-strain hysteresis behavior model of ceramic-based materials under loading and unloading is constructed, and the vibration response under arbitrary stress paths is calculated using the explicit dynamic integration method;

[0013] S3, uses computational fluid dynamics (CFD) methods to calculate the load of the gas flow field, and uses radial basis function interpolation functions to accurately map and transfer the physical quantities between the gas-solid interface to ensure the dynamic response between the fluid and the solid is coordinated;

[0014] S4, solves the stress and strain distribution in the solid domain through the Computational Structural Dynamics (CSD) method, combines the fluid load calculated by CFD to form a closed-loop feedback, and performs bidirectional coupling between the fluid domain and the solid domain;

[0015] In S5, the displacement of the solid node is fed back to the CFD fluid model to update the position of the fluid node and calculate the dynamic gas-solid coupling vibration to maintain synchronous iteration in the two domains.

[0016] Furthermore, in step S2, the physical quantities at the gas-solid interface include displacement and stress.

[0017] Furthermore, in step S2, the process of accurately mapping and transferring the physical quantities at the gas-solid interface by using the radial basis function interpolation function includes the following steps:

[0018] At the fluid-solid coupling interface, the load of the fluid domain is calculated by CFD to obtain the fluid force on the fluid-solid interface;

[0019] Write a program to map the fluid load to the nodes of the solid finite element model, and read the displacement of the solid nodes and feed it back to the fluid domain to update the status of the fluid nodes;

[0020] The Newton iteration method is used to perform the mapping calculation between fluid and solid nodes.

[0021] Furthermore, the Newton iteration method is used to perform the mapping calculation between the fluid and solid nodes, which specifically includes the following steps:

[0022] Using volume spline function As basis functions, the center points x1, x2, ..., x N The corresponding values ​​at different positions in the d-dimensional Euclidean space are g1, g2, ..., g N , there exists a continuous function passing through these center points, namely the radial basis function (RBF) interpolation function:

[0023]

[0024] Where: s(x) is the function value that changes with x, x is the coordinates of the unknown point (x, y, z), x i is the coordinate of the center point (x i ,y i ,z i ), is the radial basis function, α i is x i The unknown coefficient at ||xx i|| is the unknown point x and the center point x i The Euclidean distance of , p(x) is a low-order polynomial;

[0025] For conditionally positive basis functions, p(x) is expressed as:

[0026] p(x)=γ0+γ1x+γ2y+γ3z

[0027] The solution conditions of the RBF interpolation function are:

[0028] s(x i )=g i ,i=1,2,…,N

[0029]

[0030] Where: q(x) is all polynomials satisfying deg(q(x))≤deg(p(x));

[0031] Assume that there are n f and n f nodes, the coordinates of each node are known; use S f and S s They represent the physical quantities of aerodynamic and structural boundary nodes respectively, and data transmission is done by S f Come to S s Representation; by transferring the matrix H sf or H fs Data interaction between aerodynamics and structure is carried out for the above physical quantities; matrix M f and M s represents the radial basis function value between the aerodynamic and structural boundary nodes, Represents two known nodes x i and x j The radial basis function values ​​between them are calculated; the unknown coefficients α and γ are solved, and physical quantities are transferred between grids to ensure the effective coupling and information transfer between aerodynamic and structural calculation programs;

[0032] Among them, the RBF interpolation function of the aerodynamic boundary is expressed as:

[0033]

[0034] make: γ=[γ0 γ1 γ2 γ3] T ; α=[α1 α2 … α nf ] T ,

[0035] Where: x f1 ~x fnf ,y f1 ~yfnf ,z f1 ~z fnf Represents the coordinates of each node on the aerodynamic boundary, (x f1 ,y f1 ,z f1 ) represents the coordinates of the first aerodynamic node, (x fnf ,y fnf ,z fnf ) represents the coordinates of the nfth aerodynamic node; represents the value of the radial basis function between different aerodynamic boundary nodes, represents the radial basis function value of aerodynamic node 1 itself, represents the radial basis function value of the nfth aerodynamic node; S f1 ~S fnf Represents the physical value of each node on the aerodynamic boundary, S f1 is the physical quantity of the first aerodynamic node, S fnf is the physical quantity of the nfth aerodynamic node; nf: represents the total number of nodes on the aerodynamic boundary;

[0036] The RBF interpolation function of the aforementioned aerodynamic boundary is expressed as:

[0037]

[0038] The matrix of undetermined coefficients is:

[0039]

[0040] In RBF interpolation, the interpolation function S f It is defined as the weighted sum of various radial basis functions and polynomials to approximate the function value; for the interpolation S of the structure boundary s ,have:

[0041]

[0042] in:

[0043] Substituting the coefficient matrix into the equation, we get:

[0044]

[0045] Right now:

[0046]

[0047] The data transfer matrix from the aerodynamic grid to the structural grid is:

[0048]

[0049] The data transfer matrix from the structural grid to the aerodynamic grid is:

[0050]

[0051] The data transfer matrix is ​​used to exchange data of specific physical quantities at the aerodynamic / structural interface.

[0052] Furthermore, in step S4, the process of constructing a loading and unloading stress-strain hysteresis behavior model of the ceramic-based material by a polynomial fitting method includes:

[0053] S41, loading and unloading experiments are performed on the ceramic-based material to obtain its stress-strain hysteresis loop;

[0054] S42, the multi-scale finite element model is applied to the calculation of stress-strain hysteresis loops to obtain stress-strain curves under different loading paths;

[0055] S43, extract the stress-strain curve of each loading and unloading process respectively, and use the cubic function to fit the stress σ of the loading section based on the historical maximum strain. + and the stress σ in the unloading section - :

[0056]

[0057] The loading and unloading hysteresis loop is fitted and the polynomial coefficient a is obtained by interpolation fitting. nu ,a nu , where ε is strain, n=1,2,3,4;

[0058] Calculate the stress response under arbitrary strain conditions and establish a nonlinear constitutive model that adapts to different working conditions.

[0059] Furthermore, in step S5, the process of reading the dynamic response and updating the fluid node displacement includes the following steps:

[0060] After each time step, the dynamic response, including the displacement information of the solid nodes, is read; the position of the fluid nodes is updated by feeding the displacement information back to the fluid domain; based on the updated fluid node state, the fluid-solid coupling calculation continues for the next time step; the aforementioned steps are repeated to predict the vibration characteristics of ceramic-based composites under gas-solid coupling.

[0061] Compared with the prior art, the present invention has the following beneficial effects:

[0062] First, the present invention's gas-solid coupled vibration simulation method for ceramic-based composites utilizes RBF interpolation technology to achieve efficient transfer of physical quantities in complex fluid-solid coupled environments, ensuring accurate data exchange between the fluid and solid domains. By combining explicit dynamic integration with polynomial fitting, it accurately describes the nonlinear mechanical behavior of ceramic-based materials under high-temperature and high-pressure environments, particularly the variable stiffness and hysteresis effects.

[0063] Second, the gas-solid coupled vibration simulation method of ceramic matrix composite materials of the present invention has efficient computing performance and good computing stability, and is suitable for predicting the vibration response of ceramic matrix composite materials under complex working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 Schematic diagram of the fluid-solid coupling interface in an embodiment of the present invention.

[0065] Figure 2 Schematic diagram of a radial basis function (RBF) interpolation function in an embodiment of the present invention.

[0066] Figure 3 Schematic diagram of the stress-strain curve of the loading and unloading hysteresis loop of the ceramic-based material in an embodiment of the present invention.

[0067] Figure 4 Schematic diagram of fluid-structure coupling displacement response in an embodiment of the present invention.

[0068] Figure 5 This is a flow chart of the gas-solid coupled vibration simulation method for ceramic matrix composite materials of the present invention. DETAILED DESCRIPTION

[0069] The embodiments of the present invention are described in further detail below with reference to the accompanying drawings.

[0070] The present invention discloses a gas-solid coupling vibration simulation method for ceramic matrix composite materials, the simulation method comprising the following steps:

[0071] S1, based on ceramic-based composites under high temperature and high pressure environment, comprehensively considers the mechanical properties and thermodynamic characteristics of ceramic-based composites, and establishes a multi-scale finite element model of ceramic-based materials; the multi-scale finite element model includes micro-scale and macro-scale mechanical models. By combining the two models, the computational complexity is reduced and the computational accuracy is improved.

[0072] S2 uses CFD to calculate the load of the gas flow field and uses radial basis function (RBF) interpolation function to accurately map and transfer the physical quantities at the gas-solid interface to ensure the coordinated dynamic response between the fluid and the solid. RBF interpolation technology can perform high-precision data transmission between irregular grids, ensuring high accuracy of load and displacement transmission at the gas-solid coupling interface.

[0073] S3 uses the CSD method to solve the stress and strain distribution in the solid domain, combined with the fluid load calculated by CFD to form a closed-loop feedback, and bidirectionally couples the fluid domain and the solid domain. The fluid load calculated by CFD and the displacement of the solid node in CSD are mutually transmitted to achieve efficient coupling between the fluid and solid.

[0074] S4 uses a polynomial fitting method to construct a stress-strain hysteresis behavior model for ceramic-based materials under loading and unloading, and uses an explicit dynamic integration method to calculate the vibration response under arbitrary stress paths. Polynomial fitting is used to simulate the hysteresis behavior of ceramic-based materials, and the stress-strain characteristics under different stress paths are calculated using the fitted polynomial coefficients. The explicit dynamic integration method is used to solve the vibration response problem of ceramic-based materials under high temperature and high pressure conditions and reduce the numerical divergence caused by sudden changes in material stiffness. Combining explicit dynamics with a gas-solid coupling model can accurately predict the vibration characteristics of ceramic-based materials in high-temperature flow fields and is suitable for calculating material vibration responses in extreme environments.

[0075] In S5, the displacement of the solid node is fed back to the CFD fluid model to update the position of the fluid node and calculate the dynamic gas-solid coupling vibration to maintain synchronous iteration in the two domains.

[0076] The simulation method of the present invention is described below using a ceramic-based cantilever beam as an example. Figure 5 The simulation method of this embodiment specifically includes the following steps:

[0077] Step 1: Create a finite element model of the ceramic-based cantilever beam

[0078] First, a finite element model of a ceramic-based cantilever beam was established. This model is based on ceramic-based composites subjected to high-temperature and high-pressure environments, taking into account the mechanical properties of the material and the actual operating conditions. The meshing in the model is suitable for the complex geometry of the ceramic-based material, and appropriate boundary conditions (such as fixed boundary conditions and external loads) are set at both ends of the cantilever beam.

[0079] Figure 1 A schematic diagram of the fluid-solid coupling interface in an embodiment of the present invention. RBF interpolation technology is used for data transfer at the fluid-solid coupling interface. This RBF interpolation function accurately maps and transfers physical quantities (such as displacement and stress) between the aerodynamic and solid domains at the interface, ensuring consistent dynamic responses between the fluid and solid. Figure 2 Schematic diagram of a radial basis function (RBF) interpolation function in an embodiment of the present invention.

[0080] Step 2: Calculate the loading and unloading hysteresis loop and perform interpolation

[0081] Next, the ceramic-based material was subjected to loading and unloading experiments to obtain its stress-strain hysteresis loops. Finite element models were applied to the calculation of these hysteresis loops to obtain stress-strain curves under different loading paths. The stress-strain curves for each loading and unloading process were extracted, and a cubic function was used to fit the loading and unloading sections, based on the historical maximum strain, as described by the following polynomial:

[0082]

[0083] By fitting the loading and unloading hysteresis loops with a cubic polynomial and interpolating them, the stress response under arbitrary strain conditions is calculated. Based on this, a nonlinear constitutive model adaptable to different working conditions is established, which can effectively handle the variable stiffness and hysteresis behavior of the material. Figure 3 Schematic diagram of the stress-strain curve of the loading and unloading hysteresis loop of the ceramic-based material in an embodiment of the present invention.

[0084] Step 3: Calculate fluid loads based on CFD and implement data mapping

[0085] At the fluid-solid interface, CFD calculates the loads in the fluid domain and determines the fluid forces acting on the interface. A program is developed to map the fluid loads to the nodes of the solid finite element model, while also reading the displacements of the solid nodes and feeding them back to the fluid domain to update the state of the fluid nodes.

[0086] To ensure the accuracy of data transfer, the Newton iteration method is used to calculate the mapping between fluid and solid nodes. At each time step, the fluid domain and the solid domain are kept synchronized to ensure the accuracy of the dynamic response.

[0087] Using volume spline function As basis functions, if x1, x2, ..., x N is a set of center points, which are at different positions in the d-dimensional Euclidean space. Let the corresponding values ​​of each point be g1, g2, ..., g N , which are a set of scalar data. Therefore, there exists a continuous function passing through these center points, namely the RBF interpolation function:

[0088]

[0089] Where: s(x) is the function value that changes with x, x is the coordinates of the unknown point (x, y, z), x i is the coordinate of the center point (x i ,y i ,z i ), is the radial basis function, α i is x i The unknown coefficient at ||xx i|| is the unknown point x and the center point x i The Euclidean distance of , p(x) is a low-order polynomial.

[0090] For conditionally positive basis functions, p(x) can be expressed as:

[0091] p(x)=γ0+γ1x+γ2y+γ3z

[0092] The solution conditions of the RBF interpolation function are:

[0093] s(x i )=g i ,i=1,2,…,N

[0094]

[0095] Where: q(x) is all polynomials that satisfy deg(q(x))≤deg(p(x)).

[0096] Assume that there are points nf and nf on both sides of the aerodynamic and structural interface, and the coordinates of each node are known. f and S s Represents the physical quantities of aerodynamic and structural boundary nodes respectively, and data transmission requires S f Come to S s These physical quantities are expressed by the transfer matrix H sf or H fs Realize data interaction between aerodynamics and structure. Matrix M f and M s represents the radial basis function value between the aerodynamic and structural boundary nodes, and represents the radial basis function value between two known nodes. These matrices form a system of linear equations that allows us to solve the unknown coefficients α and γ, thereby transferring physical quantities between grids and ensuring effective coupling and information transfer between aerodynamic and structural calculation programs.

[0097] The RBF interpolation function of the aerodynamic boundary can be expressed as:

[0098]

[0099] make: γ=[γ0 γ1 γ2 γ3] T ; α=[α1 α2 … α nf ] T

[0100] , then the RBF interpolation function can be expressed as:

[0101]

[0102] Then the undetermined coefficient matrix is:

[0103]

[0104] For the structure boundaries, we have:

[0105]

[0106] in:

[0107] Substitute the coefficient matrix into

[0108]

[0109] Right now

[0110]

[0111] Therefore, the data transfer matrix from the aerodynamic grid to the structural grid is:

[0112]

[0113] Similarly, the data transfer matrix from the structural grid to the aerodynamic grid is:

[0114]

[0115] After obtaining the data transfer matrix, the data exchange of specific physical quantities at the aerodynamic / structural interface can be realized.

[0116] Step 4: Solve the vibration response of the ceramic-based cantilever beam using the explicit dynamics integration method

[0117] The vibration response of a ceramic-based cantilever beam is solved using the explicit dynamics integration method, which is capable of handling the nonlinear mechanical behavior of materials during vibration, especially sudden changes in stress and stiffness.

[0118] Ceramic-based materials are prone to nonlinear stress-strain behavior under high-temperature and high-pressure environments. The explicit dynamic integration method can stably solve these complex behaviors and ensure the robustness of the calculation results. The final vibration response results reflect the dynamic characteristics of the ceramic-based cantilever beam under complex working conditions.

[0119] Step 5: Read the dynamic response and update the fluid node displacement

[0120] After each time step, the dynamic response of the solid nodes, especially the displacement information of the nodes, is read. By feeding this displacement information back to the fluid domain, the position of the fluid nodes is updated.

[0121] Based on the updated fluid node state, the fluid-structure interaction calculation continues for the next time step, ensuring the continuity and accuracy of the entire simulation process. Through this cyclic calculation process, the vibration characteristics of the ceramic-based cantilever beam under gas-structure interaction can be accurately predicted. Figure 4 Schematic diagram of fluid-structure coupling displacement response in an embodiment of the present invention.

[0122] The above specific implementation method describes in detail the steps and application scenarios of the ceramic-based cantilever beam vibration calculation method based on RBF gas-solid thermal coupling of the present invention, and demonstrates how to realize the dynamic response calculation of ceramic-based materials in high temperature and high pressure environments through RBF interpolation technology and CFD combined with explicit dynamic integration method.

[0123] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code. The scheme in the embodiment of the present application can be implemented in various computer languages, for example, object-oriented programming language Java and literal translation scripting language JavaScript, etc.

[0124] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0125] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0126] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions for executing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0127] 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.

[0128] 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 gas-solid coupling vibration simulation method for ceramic matrix composite materials, characterized in that: The simulation method comprises the following steps: S1, based on ceramic matrix composites under high temperature and high pressure environment, comprehensively consider the mechanical properties and thermodynamic characteristics of ceramic matrix composites, and establish a multi-scale finite element model of ceramic matrix materials; S2, by using the polynomial fitting method, a stress-strain hysteresis behavior model of ceramic-based materials under loading and unloading is constructed, and the vibration response under arbitrary stress paths is calculated using the explicit dynamic integration method; S3 uses CFD to calculate the load of the gas flow field and accurately maps and transfers the physical quantities between the gas-solid interface through radial basis function interpolation to make the dynamic response between the fluid and the solid coordinated; S4, solves the stress and strain distribution in the solid domain by the CSD method, combines it with the fluid load calculated by CFD to form a closed-loop feedback, and performs bidirectional coupling between the fluid domain and the solid domain; S5, feeds the displacement of the solid node back to the CFD fluid model, updates the position of the fluid node, and calculates the dynamic gas-solid coupling vibration to maintain synchronous iteration in the two domains; In step S2, the process of constructing a loading and unloading stress-strain hysteresis behavior model of ceramic-based materials by a polynomial fitting method includes: S21, loading and unloading experiments are performed on the ceramic-based material to obtain its stress-strain hysteresis loop; S22, the multi-scale finite element model is applied to the calculation of stress-strain hysteresis loops to obtain stress-strain curves under different loading paths; S23, extract the stress-strain curve of each loading and unloading process respectively, and use the cubic function to fit the stress σ of the loading section based on the historical maximum strain. + and the stress σ in the unloading section _ : The loading and unloading hysteresis loop is fitted and the polynomial coefficient a is obtained by interpolation fitting. nu ,a nd , where ε is strain, n=1,2,3,4; Calculate the stress response under arbitrary strain conditions and establish nonlinear constitutive models that adapt to different working conditions; In step S3, the process of accurately mapping and transferring the physical quantities at the gas-solid interface by using the radial basis function interpolation function includes the following steps: At the fluid-solid coupling interface, the load of the fluid domain is calculated by CFD to obtain the fluid force on the fluid-solid interface; Write a program to map the fluid load to the nodes of the solid finite element model, and read the displacement of the solid nodes and feed it back to the fluid domain to update the status of the fluid nodes; The Newton iteration method is used to perform the mapping calculation between fluid and solid nodes.

2. The ceramic matrix composite material gas-solid coupling vibration simulation method according to claim 1, characterized in that: In step S3, the physical quantities at the gas-solid interface include displacement and stress.

3. The gas-solid coupled vibration simulation method for ceramic matrix composite materials according to claim 1, characterized in that: The Newton iteration method is used to calculate the mapping between fluid and solid nodes, which includes the following steps: Using volume spline function As basis functions, the center points x1, x2, ..., x N The corresponding values ​​at different positions in the d-dimensional Euclidean space are g1, g2, ..., g N , there exists a continuous function passing through these center points, namely the radial basis interpolation function: Where: s(x) is the function value that changes with x, x is the coordinates of the unknown point (x, y, z), x i is the coordinate of the center point (x i ,y i ,z i ), is the radial basis function, α i is x i The unknown coefficient at ||xx i || is the unknown point x and the center point x i The Euclidean distance of , p(x) is a low-order polynomial; For conditionally positive basis functions, p(x) is expressed as: p(x)=γ0+γ1x+γ2y+γ3z The solution conditions of the RBF interpolation function are: s(x i )=g i ,i=1,2,…,N Where: q(x) is all polynomials satisfying deg(q(x))≤deg(p(x)); Assume that there are n f and n f nodes, the coordinates of each node are known; use S f and S s They represent the physical quantities of aerodynamic and structural boundary nodes respectively, and data transmission is done by S f Come to S s Representation; by transferring the matrix H sf or H fs Data interaction between aerodynamics and structure is carried out for the above physical quantities; matrix M f and M s represents the radial basis function value between the aerodynamic and structural boundary nodes, Represents two known nodes x i and x j The radial basis function values ​​between them are calculated; the unknown coefficients α and γ are solved, and physical quantities are transferred between grids to ensure the effective coupling and information transfer between aerodynamic and structural calculation programs; Among them, the radial basis interpolation function of the aerodynamic boundary is expressed as: Let: γ = [γ0 γ1 γ2 γ3] T ; α[α1 α2 … α nf T ,​ Where: (x f1 ,y f1 ,z f1 ) represents the coordinates of the first aerodynamic node, (x fnf ,y fnf ,z fnf ) represents the coordinates of the nfth aerodynamic node; represents the radial basis function value of the first aerodynamic node, represents the radial basis function value of the nfth aerodynamic node; S f1 Represents the physical quantity of the first aerodynamic node, S fnf Represents the physical quantity of the nfth aerodynamic node; nf represents the total number of nodes on the aerodynamic boundary; The RBF interpolation function of the aforementioned aerodynamic boundary is expressed as: The matrix of undetermined coefficients is: In RBF interpolation, the interpolation function S f It is defined as the weighted sum of various radial basis functions and polynomials, which is used to approximate the function value; the interpolation function S for the structure boundary s ,have: in: Substituting the coefficient matrix into the equation, we get: Right now: The data transfer matrix from the aerodynamic grid to the structural grid is: The data transfer matrix from the structural grid to the aerodynamic grid is: The data transfer matrix is ​​used to exchange data of specific physical quantities at the aerodynamic / structural interface.

4. The ceramic matrix composite material gas-solid coupling vibration simulation method according to claim 1, characterized in that: In step S5, the process of reading the dynamic response and updating the fluid node displacement includes the following steps: After each time step, the dynamic response, including the displacement information of the solid nodes, is read; the position of the fluid nodes is updated by feeding the displacement information back to the fluid domain; based on the updated fluid node state, the fluid-solid coupling calculation continues for the next time step; the aforementioned steps are repeated to predict the vibration characteristics of ceramic-based composites under gas-solid coupling.

Images