Method and system for predicting hole extrusion strength of ceramic matrix composite part

Abstract

The invention belongs to the technical field of composite material mechanics, and provides a method and system for predicting the hole extrusion strength of a ceramic-based composite material part, and the method comprises the steps: carrying out the mesh generation of a finite element geometric model of a to-be-measured part of a ceramic-based composite material; obtaining a stress field of each grid unit through a finite element simulation method; according to the stress field, adopting a three-dimensional Hashin criterion or an MMF3 criterion to carry out grid unit damage type judgment, and carrying out rigidity degradation to obtain a rigidity matrix; and acquiring the current force load by adopting the stiffness matrix and the loaded displacement load, and acquiring the hole extrusion strength according to the current force load and the hole contact area. According to the method, the extrusion strength of the hole in the part can be accurately predicted, and a foundation is laid for mechanical connection performance analysis of a composite material and high-fidelity simulation calculation of a composite material structure.

Description

Technical Field

[0001] The invention belongs to the technical field of composite material mechanics, and relates to a method and a system for predicting the hole extrusion strength of a ceramic-based composite material part. Background Art

[0002] Ceramic matrix composite connectors have a very important impact on the overall performance of composite structures. Taking the structure of an aircraft as an example, a large number of complex and dense parts are combined into a whole through different connection methods (such as mechanical connection, brazing, etc.). Among various connection methods, mechanical connection is widely favored by designers due to its strong stability, reliability and detachable flexibility.

[0003] Mechanical connection requires drilling holes on the connecting parts, connecting them with components with holes with bolts or rivets to form a new force-bearing structure. Since composite materials are anisotropic materials with complex components, most of the weak areas of the structure are near the hole edges. The force distribution and damage form of the hole edges are much more complicated than those of traditional metal materials, and they will show different mechanical behaviors when subjected to tensile and compressive loads.

[0004] Therefore, it is of great significance to the safety and stability of composite material structures to deeply analyze its mechanical connection to determine its force form and stress distribution, and to reasonably and effectively establish a tensile and compressive damage model for composite material mechanical connectors. Summary of the invention

[0005] In order to analyze the hole edges of composite materials connected by mechanical connection to improve the safety and stability of the composite materials after connection, the present invention discloses a method for predicting the hole extrusion strength of ceramic-based composite parts, the method comprising the following steps: S1. Meshing the finite element geometric model of the ceramic matrix composite part to be tested; S2. Apply elastic modulus to each grid unit for nonlinear analysis through finite element simulation method to obtain the stress field of each grid unit; S3, according to the stress field, using the three-dimensional Hashin criterion or the MMF3 (modified micromechanics failure criterion) criterion to judge the damage type of the mesh unit, and performing stiffness degradation on each of the mesh units according to the damage type to obtain a stiffness matrix; S4. Using the stiffness matrix and the loaded displacement load, obtain the current force load according to the force load peak value calculated in the previous iteration, and obtain the hole extrusion strength according to the current force load and the hole contact area.

[0006] Further, in the above step S2, through the finite element simulation method, an elastic modulus is applied to each grid element for non-linear analysis to obtain the stress field of each grid element, including: S21. Through the finite element method, a tensile elastic modulus is assigned to each direction of each grid element for linear static analysis to obtain the material principal direction stress of each grid element; S22. A tensile elastic modulus is assigned to each direction of all the grid elements with positive material principal direction stress, and a compressive elastic modulus is assigned to each direction of all the grid elements with negative material principal direction stress to obtain the stress field of each grid element.

[0007] Further, in the above step S3, according to the stress field, the three-dimensional Hashin criterion or the MMF3 criterion is used to judge the damage of the grid element, and the stiffness matrix is calculated by stiffness degradation for the grid element judged to be damaged, including: S31. Calculate the sum of the normal stresses of the stress field of each grid element, and use the sum of the normal stresses as the stress invariant; S32. Judge the positive and negative values of the stress invariant of each grid element. If the judgment is positive, judge the damage type of the grid element according to the stress field using the three-dimensional Hashin criterion; if it is negative, judge the damage type of the grid element according to the stress field using the MMF3 criterion; S33. According to the damage type, calculate the stiffness matrix of each grid element through the stiffness reduction coefficient matrix and the initial material stiffness matrix.

[0008] Furthermore, in the above step S32, judging the damage type of the grid element according to the stress field using the three-dimensional Hashin criterion includes: When , the damage type is fiber tension; When , the damage type is fiber compression; When , the damage type is matrix tension; When , the damage type is matrix compression; When , the damage type is fiber-matrix shear; When , the damage type is tensile delamination; When , the damage type is compressive delamination; Among them, it is defined that the fiber direction is represented by 1, the in-plane direction perpendicular to the fiber direction is represented by 2, and the out-of-plane direction perpendicular to the fiber direction is represented by 3; is the normal stress in the 1 direction, is the normal stress in the 2 direction, is the normal stress in the 3 direction, is the shear stress in the 1 and 2 directions, is the shear stress in the 2 and 3 directions, is the shear stress in the 1 and 3 directions, is the tensile strength in the 1 direction; is the shear strength in the 1 and 2 directions; is the compressive strength in the 1 direction.

[0009] Furthermore, in the above step S32, the damage type of the grid unit is judged according to the stress field by using the MMF3 criterion, including: When , it is judged that the damage type is fiber tensile failure; When , it is judged that the damage type is fiber compressive failure; When , it is judged that the damage type is matrix failure; Among them, T f is the fiber tensile strength, C f is the fiber compressive strength, T m is the matrix tensile strength, C m is the matrix compressive strength, S m is the matrix shear strength, k m is the matrix stress distribution coefficient, k f is the fiber stress distribution coefficient; it is defined that the fiber direction is represented by 1, the in-plane direction perpendicular to the fiber direction is represented by 2, and the out-of-plane direction perpendicular to the fiber direction is represented by 3; is the normal stress in the 1 direction, is the normal stress in the 2 direction, is the normal stress in the 3 direction, is the in-plane shear stress in the 1 and 2 directions, is the interlaminar shear stress in the 1 and 3 directions.

[0010] Preferably, the matrix stress distribution coefficient and the fiber stress distribution coefficient are calculated by the formula where, E m is the matrix elastic modulus, E f is the fiber elastic modulus, V m is the proportion of the matrix volume in the part, Vf is the fiber volume fraction in the part.

[0011] Further, in the above step S4, using the stiffness matrix and the applied displacement load, the current force load is obtained based on the peak value of the force load calculated in the previous iteration, and the hole extrusion strength is obtained according to the current force load and the hole contact area, including: S41. Calculate the current force load by multiplying the stiffness matrix and the displacement load; S42. Compare the current force load with the peak value of the force load calculated in the previous iteration. If the current force load is less than a set multiple of the peak value of the force load, stop the iteration to obtain the maximum force load in the current iteration calculation; S43. Calculate the ratio of the maximum force load to the hole contact area to obtain the hole extrusion strength.

[0012] An embodiment of the present invention further provides a prediction system for the hole extrusion strength of a ceramic matrix composite part, including a finite element model establishment module, a stress field calculation module, a damage type judgment module, a stiffness degradation module, and a hole extrusion strength calculation module.

[0013] Among them, the finite element model establishment module is used to perform mesh division on the finite element geometric model of the part to be tested of the ceramic matrix composite; The stress field calculation module is used to perform non-linear analysis by applying the elastic modulus to each grid element through the finite element simulation method to obtain the stress field of each grid element; The damage type judgment module is used to judge the damage type of the grid element according to the stress field by using the three-dimensional Hashin criterion or the MMF3 criterion; The stiffness degradation module is used to perform stiffness degradation on each grid element according to the damage type to obtain the stiffness matrix; The hole extrusion strength calculation module is used to use the stiffness matrix and the applied displacement load to obtain the current force load based on the peak value of the force load calculated in the previous iteration, and obtain the hole extrusion strength according to the current force load and the hole contact area.

[0014] Compared with the prior art, the beneficial effects that can be achieved by at least one of the above technical solutions adopted in the embodiments of this specification at least include: The method of the present invention can accurately obtain the characterization of the hole extrusion strength of ceramic matrix composites. Based on progressive damage, this method fully considers the constitutive characteristics of the different mechanical properties of tensile and compressive ceramic matrix composites. On the basis of using different elastic moduli for tension and compression, the mechanical model unit of composite material hole extrusion is divided into two categories for damage determination, that is, for tensile units, the three-dimensional Hashin criterion is used for damage determination; for compressive units, the MMF3 theory is used for damage determination. The present invention can relatively accurately obtain the characterization of the composite material constitutive curve, laying a foundation for the performance analysis of composite materials and the high-fidelity simulation calculation of composite material structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the accompanying drawings required for use in the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can also be obtained based on these drawings.

[0016] Figure 1 It is a flowchart of the method for predicting the hole extrusion strength of a ceramic matrix composite part disclosed in the embodiments of the present invention; Figure 2 It is an architecture diagram of the prediction of the hole extrusion strength of a ceramic matrix composite part disclosed in the embodiments of the present invention; Among them, 201 is a finite element model establishment module; 202 is a stress field calculation module; 203 is a damage type judgment module; 204 is a stiffness degradation module; 205 is a hole extrusion strength calculation module. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0018] The following illustrates the implementation manners of the present application through specific specific examples. Those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, without conflict, the following embodiments and the features of the embodiments can be combined with each other. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts belong to the scope of protection of the present application.

[0019] An embodiment of the present invention discloses a method for predicting the hole extrusion strength of a ceramic matrix composite part. Refer to Figure 1 as shown, the method includes the following steps: S1. Mesh the finite element geometric model of the part to be measured of the ceramic matrix composite; S2. Through the finite element simulation method, apply the elastic modulus to each mesh element for nonlinear analysis to obtain the stress field of each mesh element; S3. According to the stress field, use the three-dimensional Hashin criterion or the MMF3 criterion to judge the damage type of the mesh element, and perform stiffness degradation on each mesh element according to the damage type to obtain the stiffness matrix; S4. Use the stiffness matrix and the applied displacement load, obtain the current force load according to the peak value of the force load calculated in the previous iteration, and obtain the hole extrusion strength according to the current force load and the hole contact area.

[0020] Further, when implementing the above step S1, a commercial preprocessing software can be used to mesh the finite element geometric model of the ceramic matrix composite part. When meshing, for the hole edge, mapping division is performed with the hole center as the center to improve the accuracy of the calculation result. Generally speaking, the mesh size of the hole edge should not be greater than 1 / 16 of the hole circumference, and for the position without holes, free division can be performed.

[0021] For example, for a three-dimensional single-bolt composite connection structure finite element model, where the laminate layup sequence is [45 / 0 / -45 / 90] 2s , the total thickness of the laminate is 3.2 mm, the thickness of each layer is the same, and the material properties of each layer are the same. Use a general finite element software to assign the laminate layup and use the corresponding module in the software to mesh. Since the full integration element is prone to shear locking phenomenon, reduced integration is used to improve the reliability of the model, reduce the calculation error and save the time cost.

[0022] Further, after establishing the finite element model through step S1, stress calculation is performed. When calculating the stress, first use a static load to assign the tensile elastic modulus to all mesh elements (including the tensile elastic modulus applied in the fiber direction and along the vertical direction of the laminate), perform a pre-analysis to obtain the initial stress field, and then extract the material principal direction stress for each mesh element according to the initial stress field. If the stress is positive, assign the tensile elastic modulus in this direction; if the stress is negative, assign the compressive elastic modulus in this direction to reorganize the stiffness matrix and obtain the stress field in the initial state. Specifically, in the above step S2, through the finite element simulation method, applying the elastic modulus to each mesh element for nonlinear analysis to obtain the stress field of each mesh element includes the following steps: S21. Perform linear static analysis by assigning tensile elastic moduli to each direction of each mesh element using the finite element method, and obtain the material principal direction stress of each mesh element. S22. Assign tensile elastic moduli to each direction of all the mesh elements with positive material principal direction stress, and assign compressive elastic moduli to each direction of all the mesh elements with negative material principal direction stress, to obtain the stress field of each mesh element. In this step, the values of the assigned compressive elastic modulus and tensile elastic modulus are different.

[0023] Further, in the above step S3, according to the stress field, use the three-dimensional Hashin criterion or the MMF3 criterion to judge the damage of the mesh elements, and calculate the stiffness matrix with stiffness degradation for the mesh elements judged to be damaged, including: S31. Calculate the sum of the normal stresses of the stress field of each mesh element, and take the sum of the normal stresses as the stress invariant. S32. Judge the positive and negative values of the stress invariant of each mesh element. If it is judged to be positive, judge the damage type of the mesh element according to the stress field using the three-dimensional Hashin criterion; if it is negative, judge the damage type of the mesh element according to the stress field using the MMF3 criterion. S33. According to the damage type, calculate the stiffness matrix of each mesh element through the stiffness reduction coefficient matrix and the initial material stiffness matrix.

[0024] Even further, in the above step S32, judging the damage type of the mesh element according to the stress field using the three-dimensional Hashin criterion includes: (1) When the damage type is fiber tension; (2) When the damage type is fiber compression; (3) When the damage type is matrix tension; (4) When the damage type is matrix compression; (5) When the damage type is fiber-matrix shear; (6) When the damage type is tensile delamination; (7) When the damage type is compressive delamination; Among them, it is defined that the fiber direction is represented by 1, the in-plane direction perpendicular to the fiber direction is represented by 2, and the out-of-plane direction perpendicular to the fiber direction is represented by 3; is the normal stress in the 1 direction, is the normal stress in the 2 direction, is the normal stress in the 3 direction, is the shear stress in the 1 and 2 directions, is the shear stress in the 2 and 3 directions, is the shear stress in the 1 and 3 directions, is the tensile strength in the 1 direction; is the shear strength in the 1 and 2 directions; is the compressive strength in the 1 direction.

[0025] Furthermore, a cross-scale failure criterion based on the MMF3 criterion is used to simulate the damage of the composite material under compressive load. It can analyze the stress states of the fibers and the matrix from the mesoscopic level and define the failure behaviors of the fibers and the matrix respectively, which can truly reflect the material properties of the fibers and the matrix. Specifically, in the above step S32, according to the stress field, the MMF3 criterion is used to judge the damage type of the grid unit, including: (1) When , it is judged that the damage type is fiber tensile failure; (2) When , it is judged that the damage type is fiber compressive failure; (3) When , it is judged that the damage type is matrix failure; In the formula, is the macroscopic stress of the single-layer flat plate. Five mesoscopic strength parameters are specified for the fibers and the matrix, namely . Among them, T f is the fiber tensile strength, C f is the fiber compressive strength, T m is the matrix tensile strength, C m is the matrix compressive strength, S m is the matrix shear strength. The above several strength parameters belong to material properties and can be obtained from the material handbook. k m is the matrix stress distribution coefficient, k f is the fiber stress distribution coefficient; it is defined that the fiber direction is represented by 1, the in-plane direction perpendicular to the fiber direction is represented by 2, and the out-of-plane direction perpendicular to the fiber direction is represented by 3; is the normal stress in the 1 direction, is the normal stress in the 2 direction, is the normal stress in the 3 direction, is the in-plane shear stress in the 1 and 2 directions, is the interlaminar shear stress in the 1 and 3 directions.

[0026] Furthermore, the matrix stress distribution coefficient and the fiber stress distribution coefficient are calculated by the formula wherein, E m is the matrix elastic modulus, E f is the fiber elastic modulus, V m is the matrix volume fraction in the part, V f is the fiber volume fraction in the part.

[0027] When it is judged that damage occurs and the damage type is determined through step S32, the method of step S33 is adopted to perform stiffness proportional reduction using the stiffness reduction coefficient matrix M At this time, the concept of the damage variable matrix D in damage mechanics also needs to be introduced. The law of the instantaneous degradation model is shown in the following formula: ; In the above formula, when failure occurs and affects the material, the stiffness matrix is represented by E * E represents the initial material stiffness matrix, M M is the stiffness reduction coefficient matrix, 0 ≤ M ≤ 1. In the gradual degradation model, when the stress and strain increase, the material stiffness also changes, that is, the stiffness parameters of the material degenerate according to a certain linear or non - linear function form.

[0028] Furthermore, in the above - mentioned step S4, using the stiffness matrix and the applied displacement load, the current force load is obtained based on the peak force load calculated in the previous iteration, and the hole extrusion strength is obtained according to the current force load and the hole contact area, including: S41. Calculate the current force load by multiplying the stiffness matrix and the displacement load; S42. Compare the current force load with the peak force load calculated in the previous iteration. If the current force load is less than a set multiple of the peak force load, stop the iteration to obtain the maximum force load in the current iteration calculation. In this embodiment, it is selected to stop the calculation when the current force load drops to 40% of the peak force load; S43. Calculate the ratio of the maximum force load to the hole contact area to obtain the hole extrusion strength.

[0029] The method of the present invention can accurately obtain the hole extrusion strength of ceramic matrix composites. Based on progressive damage, this method fully considers the constitutive characteristics of different mechanical properties of ceramic matrix composites in tension and compression. On the basis of using different elastic moduli for tension and compression, the mechanical model unit of the composite material hole extrusion is divided into two categories for damage determination. That is, for the tensile unit, the three-dimensional Hashin criterion is used for damage determination; for the compressive unit, the MMF3 theory is used for damage determination. The present invention can relatively accurately obtain the constitutive curve of the composite material, laying a foundation for the performance analysis of the composite material and the high-fidelity simulation calculation of the composite material structure.

[0030] Based on the same inventive concept, an embodiment of the present invention also provides a hole extrusion strength prediction system for a ceramic matrix composite part, as described in the following embodiments. Since the principle of solving problems by the hole extrusion strength prediction system for a ceramic matrix composite part is similar to the hole extrusion strength prediction method for a ceramic matrix composite part disclosed in the above embodiments, the implementation of the hole extrusion strength prediction system for a ceramic matrix composite part can refer to the implementation of the hole extrusion strength prediction method for a ceramic matrix composite part, and the repeated parts will not be elaborated. As used hereinafter, the term "unit" or "module" may be a combination of software and / or hardware that can implement a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, implementation in hardware, or a combination of software and hardware is also possible and contemplated.

[0031] Figure 2 is a structural block diagram of a hole extrusion strength prediction system for a ceramic matrix composite part disclosed in an embodiment of the present invention, as Figure 2 shown. The system includes a finite element model establishment module 201, a stress field calculation module 202, a damage type judgment module 203, a stiffness degradation module 204, and a hole extrusion strength calculation module 205. The following will explain this structure.

[0032] Among them, the finite element model establishment module 201 is used to perform mesh division on the finite element geometric model of the part to be tested of the ceramic matrix composite material; The stress field calculation module 202 is used to perform non-linear analysis by applying an elastic modulus to each grid unit through a finite element simulation method to obtain the stress field of each grid unit; The damage type judgment module 203 is used to judge the damage type of the grid unit according to the stress field by using the three-dimensional Hashin criterion or the MMF3 criterion; The stiffness degradation module 204 is used to perform stiffness degradation on each of the grid units according to the damage type to obtain a stiffness matrix; The hole extrusion strength calculation module 205 is configured to use the stiffness matrix and the applied displacement load, obtain the current force load based on the peak value of the force load calculated in the previous iteration, and obtain the hole extrusion strength according to the current force load and the hole contact area.

[0033] In this embodiment, a computer device is provided, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the hole extrusion strength prediction method for any of the above ceramic matrix composite parts is implemented.

[0034] Specifically, the computer device may be a computer terminal, a server, or a similar computing device.

[0035] In this embodiment, a computer-readable storage medium is provided, and the computer-readable storage medium stores a computer program for executing the hole extrusion strength prediction method for any of the above ceramic matrix composite parts.

[0036] Specifically, the computer-readable storage medium includes permanent and non-permanent, removable and non-removable media, and information storage can be implemented by any method or technology. The information may be computer-readable instructions, data structures, program modules, or other data. Examples of computer-readable storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory, or other memory technologies, compact disc read-only memory (CD-ROM), digital versatile disc (DVD), or other optical storage, magnetic cassette tapes, magnetic disk storage, or other magnetic storage devices, or any other non-transmission medium that can be used to store information accessible by a computing device. As defined herein, computer-readable storage media do not include transitory media such as modulated data signals and carrier waves.

[0037] Obviously, those skilled in the art should understand that the above modules or steps of the embodiments of the present invention can be implemented by a general-purpose computing device. They can be concentrated on a single computing device or distributed on a network composed of multiple computing devices. Optionally, they can be implemented by program codes executable by the computing device, so that they can be stored in the storage device and executed by the computing device. And in some cases, the steps shown or described herein can be executed in a different order, or they can be separately fabricated into individual integrated circuit modules, or multiple modules or steps among them can be fabricated into a single integrated circuit module to be implemented. In this way, the embodiments of the present invention are not limited to any specific combination of hardware and software.

[0038] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, various modifications and variations can be made to the embodiments of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for predicting the hole extrusion strength of a ceramic matrix composite part, characterized in that, Including: Performing mesh generation on the finite element geometric model of the part to be measured of the ceramic matrix composite material; By means of finite element simulation method, applying elastic modulus to each mesh element for non-linear analysis to obtain the stress field of each mesh element; According to the stress field, using the three-dimensional Hashin criterion or MMF3 criterion to judge the damage type of the mesh element, and performing stiffness degradation on each mesh element according to the damage type to obtain the stiffness matrix; Using the stiffness matrix and the applied displacement load, obtaining the current force load based on the peak value of the force load calculated in the previous iteration, and obtaining the hole extrusion strength according to the current force load and the hole contact area.

2. The method for predicting the hole extrusion strength of a ceramic matrix composite part according to claim 1, wherein By means of finite element simulation method, applying elastic modulus to each mesh element for non-linear analysis to obtain the stress field of each mesh element, including: By means of finite element method, assigning tensile elastic modulus to each direction of each mesh element for linear static analysis to obtain the material principal direction stress of each mesh element; Assigning the tensile elastic modulus to each direction of all the mesh elements with positive material principal direction stress, and assigning the compressive elastic modulus to each direction of all the mesh elements with negative material principal direction stress to obtain the stress field of each mesh element.

3. The method for predicting the hole extrusion strength of a ceramic matrix composite part according to claim 1, wherein According to the stress field, using the three-dimensional Hashin criterion or MMF3 criterion to judge the damage of the mesh element, and performing stiffness degradation calculation on the mesh element judged to be damaged to obtain the stiffness matrix, including: Calculating the sum of the normal stresses of the stress field of each mesh element, and taking the sum of the normal stresses as the stress invariant; Judging the positive and negative values of the stress invariant of each mesh element. If the judgment is positive, using the three-dimensional Hashin criterion according to the stress field to judge the damage type of the mesh element; if it is negative, using the MMF3 criterion according to the stress field to judge the damage type of the mesh element; According to the damage type, calculating the stiffness matrix of each mesh element through the stiffness reduction coefficient matrix and the initial material stiffness matrix.

4. The method for predicting the hole extrusion strength of a ceramic matrix composite part according to claim 3, characterized in that, Judging the damage type of the mesh element using the three-dimensional Hashin criterion according to the stress field, including: When the damage type is fiber stretching; When the damage type is fiber compression; When the damage type is matrix tension; When the damage type is matrix compression; When the damage type is fiber-matrix shear; When the damage type is tensile delamination; When the damage type is compression delamination; Among them, the fiber direction is defined as 1, the in-plane direction perpendicular to the fiber direction is defined as 2, and the out-of-plane direction perpendicular to the fiber direction is defined as 3; is the normal stress in the 1 direction, is the normal stress in the 2 direction, is the normal stress in the 3 direction, is the shear stress in the 1 and 2 directions, is the shear stress in the 2 and 3 directions, is the shear stress in the 1 and 3 directions, is the tensile strength in the 1 direction; is the shear strength in the 1 and 2 directions; is the compressive strength in the 1 direction.

5. The method for predicting the hole extrusion strength of a ceramic matrix composite part according to claim 3, characterized in that Judging the damage type of the mesh element using the MMF3 criterion according to the stress field, including: When it is determined that the damage type is fiber tensile failure; When it is determined that the damage type is fiber compression failure; When , it is determined that the damage type is matrix failure; Among them, T f is the fiber tensile strength, C f is the fiber compressive strength, T m is the matrix tensile strength, C m is the matrix compressive strength, S m is the matrix shear strength, k m is the matrix stress distribution coefficient, k f is the fiber stress distribution coefficient; it is defined that the fiber direction is represented by 1, the in-plane direction perpendicular to the fiber direction is represented by 2, and the out-of-plane direction perpendicular to the fiber direction is represented by 3; is the normal stress in the 1 direction, is the normal stress in the 2 direction, is the normal stress in the 3 direction, is the in-plane shear stress between the 1 direction and the 2 direction, is the interlaminar shear stress between the 1 direction and the 3 direction.

6. The method for predicting the hole extrusion strength of the ceramic matrix composite part according to claim 5, characterized in that, The matrix stress distribution coefficient and the fiber stress distribution coefficient are calculated by the formula where E m is the matrix elastic modulus, E f is the fiber elastic modulus, V m is the matrix volume fraction in the part, V f is the fiber volume fraction in the part.

7. The method for predicting the hole extrusion strength of the ceramic matrix composite part according to claim 1, characterized in that, Using the stiffness matrix and the applied displacement load, obtaining the current force load based on the peak value of the force load calculated in the previous iteration, and obtaining the hole extrusion strength according to the current force load and the hole contact area, including: Calculating the current force load through the product of the stiffness matrix and the displacement load; Comparing the current force load with the peak value of the force load calculated in the previous iteration. If the current force load is less than the set multiple of the peak value of the force load, stop the iteration to obtain the maximum force load in the current iteration calculation; Calculating the ratio of the maximum force load to the hole contact area to obtain the hole extrusion strength.

8. A prediction system for the hole extrusion strength of a ceramic matrix composite part, characterized in that, Including: Finite element model establishment module, the finite element model establishment module is used to perform mesh generation on the finite element geometric model of the part to be measured of the ceramic matrix composite material; A stress field calculation module, which is used to perform nonlinear analysis by applying elastic modulus to each grid element through the finite element simulation method to obtain the stress field of each grid element; A damage type judgment module, which is used to judge the damage type of grid elements according to the stress field by using the three-dimensional Hashin criterion or the MMF3 criterion; A stiffness degradation module, which is used to perform stiffness degradation on each grid element according to the damage type to obtain a stiffness matrix; A hole extrusion strength calculation module, which is used to use the stiffness matrix and the applied displacement load to obtain the current force load according to the peak value of the force load calculated in the previous iteration, and obtain the hole extrusion strength according to the current force load and the hole contact area.

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