A model construction and simulation method, device and storage medium for braided composite materials

Abstract

The present invention discloses a model construction and simulation method, device and storage medium for woven composite materials. The method, device and storage medium are as follows: at the microscale, material properties are assigned to a fiber bundle model and a porous matrix model, and then multi-physics field loads are applied and thermo-mechanical responses are extracted; the micromodel is homogenized into material properties and transferred to a mesoscopic model; at the mesoscale, a woven composite material model is constructed through structural parameters, and properties are assigned to the homogenized fiber bundle and the homogenized porous matrix; periodic boundary conditions and multi-physics field loads of the service conditions of the macrostructure are applied to the mesoscopic model to obtain the thermo-mechanical response and performance degradation of the mesoscopic model, as well as fatigue damage under cyclic loads, and complete progressive failure analysis; the actual response of the macrostructure under multi-physics fields is obtained; and low-cost, high-precision multi-scale and multi-physics field numerical simulation and performance prediction are achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of composite materials, and in particular relates to a model construction and simulation method, device and storage medium for a braided composite material. Background Art

[0002] In existing technologies, because woven composite materials are made of fiber bundles woven along the warp and weft directions and have complex microstructures, testing them under multi-physics loads, such as thermal cycling, is costly, and microscopic damage and thermo-mechanical responses are difficult to observe. Based on numerical methods and material constitutive models, a multi-scale micro-meso-macro model is constructed that considers the distribution of pores in the matrix, the weaving pattern, and the phase properties of the material, as well as the changes in the material constitutive and microstructural changes under thermal cycling loads. This can be used to guide structural design and reduce testing costs.

[0003] A new modeling and simulation method for braided composite materials is needed. Summary of the Invention

[0004] The purpose of the present invention is to provide a model construction and simulation method for a braided composite material, so as to solve the technical problems of high experimental cost and low measurement accuracy in the prior art.

[0005] The present invention also aims to provide a device for realizing a model construction and simulation method of a braided composite material.

[0006] Another object of the present invention is to provide a computer-readable storage medium.

[0007] The technical solution of the present invention to solve the technical problem is:

[0008] A method for modeling and simulating a braided composite material comprises the following steps:

[0009] S1: Establish a fiber bundle model containing fibers, matrix, pores, and interfaces, and a porous matrix model containing pores and matrix, respectively, at the microscale of the woven composite material. Assign material properties to the fiber bundle model and the porous matrix model based on existing material library data or observation data during the test process. Based on the observation results, assign structural parameters at the microscale to complete the construction of the multi-scale model.

[0010] S2: By applying multi-physics field loads transferred from the microscopic model to the fiber bundle model and porous matrix model after the material properties are assigned, and extracting the response, the material performance degradation related to elastic-plastic constitutive properties, high-temperature thermal properties, and fracture energy is obtained; the performance of the microscopic model is equivalent to a thermo-mechanical response curve, which is then homogenized and transferred to the homogenized fiber bundle and homogenized porous matrix in the microscopic woven composite material model;

[0011] S3: Assign properties to homogenized fiber bundles and homogenized porous matrices at the microscopic scale of woven composite materials; convert the service conditions of the macroscopic structure into loads and boundary conditions, apply them to the microscopic model, calculate the multi-physics field response as load and transfer it to the microscopic model; after the thermo-mechanical response is updated, the performance degradation of the microscopic model and the fatigue damage under cyclic load are obtained, and the progressive failure analysis is completed; the actual response of the macroscopic structure under multi-physics fields is obtained.

[0012] Furthermore, the structural parameters in step S1 include the diameter, aspect ratio, volume fraction, distribution mode of the fibers and the median pore size, shape, distribution mode, porosity of the pores at the microscopic scale, as well as the weaving density / bundle / cm, linear density / tex, and weaving mode of the warp and weft yarns at the microscopic scale; the material properties include the mechanical and thermal properties of the initial matrix phase, interface phase, and fiber phase.

[0013] Furthermore, the multi-physical field load in step S2 includes stress-strain field load, heat flow load, and temperature load.

[0014] Furthermore, the high-temperature thermal properties in step S2 include thermal expansion coefficient, thermal conductivity, specific heat capacity, and thermal diffusivity at different temperatures.

[0015] Furthermore, the progressive failure analysis in step S3 includes three parts: stress analysis, failure analysis, and material degradation.

[0016] Furthermore, the imparting of properties to the homogenized fiber bundles and the homogenized porous matrix on a microscopic scale of the woven composite material in step S3 specifically includes the following steps:

[0017] Q1: Based on the ABAQUS solver, the strain field of the braided composite material is obtained through the finite element model, and the initial stress field of the braided composite material is calculated based on the stiffness matrix constructed by the mesh nodes;

[0018] Q2: The initial stress fields of the warp / weft yarns and the equivalent matrix are calculated using the microscopic model. These are then processed into step Q3 for homogenized fiber bundles and step Q4 for homogenized porous matrix to perform failure judgment and stress update.

[0019] Q3: Based on the ratio of stress to strength in the principal direction of the material, calculate the sum obtained by weighted average and determine whether the damage variable is greater than 1. If so, proceed to step Q3.1; if not, proceed to step Q5;

[0020] Q3.1: Degrade the stiffness of the homogenized fiber bundle along the linear decline curve according to the strain value. Determine whether the degraded stiffness value is zero based on the fracture energy data. If so, perform integration point failure and mesh deletion operations and proceed to step Q5; if not, proceed to step Q5;

[0021] Q4: Determine whether the stress value in the main direction of the material is higher than the strength value. If so, go to step Q4.1; if not, go to step Q5;

[0022] Q4.1: Calculate the magnitude of ductile deformation of the homogenized porous matrix using the material constitutive model for ductile fracture and determine whether the magnitude is below the fracture threshold. If so, proceed to step Q5. If not, fracture the homogenized porous matrix, perform integration point failure and mesh deletion, and proceed to step Q5.

[0023] Q5: Update the stress field, strain field and overall stiffness matrix of woven composite materials.

[0024] A device for implementing a model construction and simulation method for a braided composite material, comprising:

[0025] The microstructure processing module is used to establish a fiber bundle model containing fibers, matrix, pores, and interfaces, and a porous matrix model containing pores and matrix. Structural parameters and material properties are assigned to the fiber bundle model and the porous matrix model based on existing material library data or observation data during the test process. By applying cyclic temperature fields and multi-physics field loads to the assigned fiber bundle model and the porous matrix model and extracting responses, the degradation of material properties related to elastic-plastic constitutive properties, high-temperature thermal properties, and fracture energy after thermal cycling is obtained. The fiber bundle model and the porous matrix model are homogenized into the material properties and transferred to the microstructure model.

[0026] The microstructure processing module is used to impart properties to homogenized fiber bundles and homogenized porous matrices. It applies the periodic boundary conditions and multi-physics field loads of the macrostructure's service conditions to the micromodel to obtain the thermo-mechanical response and performance degradation of the micromodel, as well as fatigue damage under cyclic loads, and completes progressive failure analysis. It also obtains the actual response of the macrostructure under multi-physics fields.

[0027] The judgment module is used to judge whether the damage variable is greater than 1; whether the stiffness value after degradation is zero; whether the stress value in the main direction of the material is higher than the strength value; and whether the amplitude of ductile deformation is lower than the fracture threshold.

[0028] A computer-readable storage medium stores a computer program, wherein when the computer program is executed by a processor, the device where the computer-readable storage medium is located executes a model construction and simulation method for a woven composite material.

[0029] The beneficial effects of the present invention are:

[0030] By assigning material properties to fiber bundle models and porous matrix models at the microscale, applying multi-physics loads and extracting thermo-mechanical responses, homogenizing the micromodel into material properties and transferring them to the mesoscale model, and constructing a woven composite material model at the mesoscale using structural parameters to assign properties to the homogenized fiber bundle and porous matrix, applying periodic boundary conditions and multi-physics loads of the macrostructure's service conditions to the mesoscale model, the thermo-mechanical response and performance degradation of the mesoscale model, as well as fatigue damage under cyclic loading, are obtained to complete progressive failure analysis, and the actual response of the macrostructure under multi-physics is obtained. This enables low-cost, high-precision multi-scale and multi-physics numerical simulation and performance prediction. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A flow chart of the model building and simulation method of the present invention;

[0032] Figure 2 This is the flow chart of the UMAT subroutine when used for progressive failure analysis;

[0033] Figure 3 The present invention relates to the construction of a micro-meso-macro multi-scale model of the woven composite material;

[0034] Figure 4 Material phase distribution and mesh division of the multi-scale model: (a) micro-porous matrix; (b) micro-fiber bundle; (c)-(d) micro-woven composite material;

[0035] Figure 5 Simulation analysis of thermal cycle fatigue damage process of braided composite materials;

[0036] Figure 6 A research proposal for using multi-scale models for thermal cycling performance degradation simulation. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention.

[0038] Example 1:

[0039] like Figure 1 As shown, the present invention discloses a model construction and simulation method of a braided composite material, comprising the following steps:

[0040] S1: Establish a fiber bundle model containing fibers, matrix, pores, and interfaces, and a porous matrix model containing pores and matrix, respectively, at the microscale of the woven composite material. Assign material properties to the fiber bundle model and the porous matrix model based on existing material library data or observation data during the test process. Based on the observation results, assign structural parameters at the microscale to complete the construction of the multi-scale model.

[0041] Among them, the structural parameters include the diameter, aspect ratio, volume fraction, distribution mode of the fibers and the median pore size, shape, distribution mode, porosity of the pores at the microscopic scale, as well as the weaving density / bundle / cm, linear density / tex, and weaving mode of the warp and weft yarns at the microscopic scale; the material properties include the mechanical and thermal properties of the initial matrix phase, interface phase, and fiber phase.

[0042] S2: Multi-physics field loads transferred from the microscopic model are applied to the fiber bundle model and porous matrix model after material properties have been assigned, and the responses are extracted. Multi-physics field loads include stress-strain field loads, heat flow loads, and temperature loads. For example, applying uniaxial / multiaxial tensile loads can obtain stress-strain curves, which are characterized by elastic-plastic constitutive properties. Applying heat flow loads can obtain temperature field-time relationships, which are characterized by thermophysical properties. Applying temperature loads can obtain strain field-temperature relationships, which are characterized by the thermal expansion coefficient. The elastic-plastic constitutive property describes the deformation of the material under stress, which includes elastic and plastic deformation. For example, in the ductile fracture model used in strength analysis, the stress-strain curve is divided into elastic, yield, stiffness degradation, and fracture stages. In the kinematic bilinear hardening constitutive model used in thermal cycling fatigue analysis, the elastic modulus, yield strength, and tangent modulus are all temperature- and cycle-dependent. Thermophysical properties used in heat transfer analysis include thermal conductivity, thermal diffusivity, specific heat capacity, and other temperature-dependent properties. After thermal cycling, material degradation is determined for elastic-plastic constitutive properties, high-temperature thermal properties, and fracture energy. These high-temperature thermal properties include thermal expansion coefficient, thermal conductivity, specific heat capacity, and thermal diffusivity at different temperatures. The microscopic model's performance is converted into a thermo-mechanical response curve, homogenized, and then transferred to the warp / weft homogenized fiber bundles and the equivalent matrix homogenized porous matrix in the mesoscopic woven composite model.

[0043] S3: Assign properties to homogenized fiber bundles and homogenized porous matrices at the microscopic scale of woven composite materials; convert the service conditions of the macroscopic structure into loads and boundary conditions, apply them to the microscopic model, calculate the multi-physics field response as load and transfer it to the microscopic model; after the thermo-mechanical response is updated, the performance degradation of the microscopic model and the fatigue damage under cyclic load are obtained, and the progressive failure analysis is completed; the actual response of the macroscopic structure under multi-physics fields is obtained.

[0044] Among them, the service conditions of macroscopic structures include: stress fields generated by displacement loads, such as multi-axial tension, compression, and shear loads; temperature fields and thermal stress fields generated by heat transfer, as well as the convection / conduction / radiation methods used; time-related alternating loads, such as thermal cycles caused by alternating heating and displacement cycles caused by repeated loading; physical fields caused by extreme working conditions, such as ablation oxidation and surface ionization.

[0045] Progressive failure analysis includes three parts: stress analysis, failure analysis, and material degradation. The stress-strain field can be obtained by applying loads and boundary condition analysis in the finite element model. Failure analysis is responsible for detecting whether the grid integration point has failed and determining the failure mode. Material degradation is used to describe the stiffness degradation process after the integration point fails.

[0046] Typical failure forms include: matrix fragmentation and matrix peeling at the mesoscopic scale, fiber bundle breakage, and fiber bridging, fiber pullout, matrix cracking, and interface debonding at the microscopic scale.

[0047] like Figure 2 As shown, the step S3 of imparting properties to the homogenized fiber bundles and the homogenized porous matrix on a microscopic scale of the woven composite material specifically includes the following steps:

[0048] Q1: Based on the ABAQUS solver, the strain field of the braided composite material is obtained through the finite element model, and the initial stress field of the braided composite material is calculated based on the stiffness matrix constructed by the mesh nodes;

[0049] Q2: The initial stress fields of the warp / weft yarns and the equivalent matrix are calculated using the microscopic model. These are then processed into step Q3 for homogenized fiber bundles and step Q4 for homogenized porous matrix to perform failure judgment and stress update.

[0050] Q3: Based on the ratio of stress to strength in the principal direction of the material, calculate the sum obtained by weighted average and determine whether the damage variable is greater than 1. If so, proceed to step Q3.1; if not, proceed to step Q5;

[0051] Q3.1: Degrade the stiffness of the homogenized fiber bundle along the linear decline curve according to the strain value. Determine whether the degraded stiffness value is zero based on the fracture energy data. If so, perform integration point failure and mesh deletion operations and proceed to step Q5; if not, proceed to step Q5;

[0052] Q4: Determine whether the stress value in the main direction of the material is higher than the strength value. If so, go to step Q4.1; if not, go to step Q5;

[0053] Q4.1: Calculate the magnitude of ductile deformation of the homogenized porous matrix using the material constitutive model for ductile fracture and determine whether the magnitude is below the fracture threshold. If so, proceed to step Q5. If not, fracture the homogenized porous matrix, perform integration point failure and mesh deletion, and proceed to step Q5.

[0054] Q5: Update the stress field, strain field and overall stiffness matrix of woven composite materials.

[0055] Taking a woven composite material with a warp density of 8 yarns / cm and a weft density of 2.5 yarns / cm, where the fiber density in the warp and weft yarns is 205 tex and the volume fraction is 43%, as an example, the specific model construction and simulation methods are as follows:

[0056] S1: Establish a multi-scale model based on experimental observations. It is observed that the warp density of the woven composite material is 8 yarns / cm and the weft density is 2.5 yarns / cm. The fiber density in the warp and weft yarns is 205 tex and the volume fraction is 43%. Figure 3 As shown in Figure 1-a, the smallest element was selected to establish a microscopic model with dimensions of 16×5×3.8 mm. The warp and weft yarns and the matrix were observed using a scanning electron microscope, and the fiber diameter in the fiber bundle was measured to be 10 μm, the fiber volume fraction Vf = 73.23%; the porosity (density method) in the porous matrix was 52.7%, and the median pore size (mercury intrusion method) was 0.6 μm. Figure 3 -b, a microscopic fiber bundle model with a side length of 50 μm is established, as shown in Figure 3 -c, a microscopic porous matrix model with a side length of 1 μm was established.

[0057] The model is meshed and boundary conditions are applied. The models in this embodiment are constructed using Digmat software and solved using ABAQUS / Standard. The meshing of the multi-scale model is as follows Figure 4 As shown in the figure, the mesh type for each material phase is four-node linear tetrahedral elements (C3D4). Surface / surface interactions are defined using general contact, with a tangential friction coefficient of 0.5. Because the microelements are selected from the macrostructure, it is necessary to ensure that the model deforms in a coordinated manner when loaded. Therefore, periodic boundary conditions (PBCs) are applied to each external surface of the model, imposing coupling constraints on the nodes of the opposite surface to ensure that each node displaces equally when loaded.

[0058] S2: Analysis of fatigue damage process of thermal cycle. First, set the initial temperature of micro and meso models to 0℃ (room temperature is also acceptable), then raise the temperature field to a constant value (400℃), then lower it to the initial temperature, and end the analysis after the sinusoidal curve cycles for the specified number of times (100 times). Figure 5As shown in Figure 1-a, at the microscopic level, due to the huge difference in thermal expansion coefficients between the fiber and the matrix and the high modulus of the fiber, the matrix will produce alternating thermal stress, and after multiple thermal cycles, multiple fracture zones will be generated in the longitudinal direction and the structure will tend to be stable. Figure 5 As shown in Figure 2-b, as the number of warm-heat cycles increases, the stress on some interfaces accumulates and exceeds the strength, resulting in interface debonding. Figure 5 As shown in Figure 1-c, due to the random distribution of pores in the matrix, thermal stress is not uniformly transmitted in the matrix, and stress concentration occurs at the pore agglomeration; therefore, matrix cracking occurs first at the pore agglomeration and continues with the thermal cycle until complete failure. At the microscopic level, due to the large difference in the transverse and longitudinal thermal expansion coefficients of the fiber bundles, there is severe stress concentration at the intersection interface of the warp yarn (x-axis carbon fiber bundle) and the weft yarn (y-axis carbon fiber bundle). Figure 5 As shown in Figure 3-d, as the number of cycles increases, the plastic zone is generated from the intersection interface and grows along the thickness direction, and finally a certain amount of microcracks are generated.

[0059] like Figure 6 As shown in the simulation of performance degradation after thermal cycling, even if the fiber performance is stable at high temperature, matrix cracking and interface debonding will cause the fiber bundle performance to degrade as the temperature rises. The microscopic model after thermal cycling can be subjected to uniaxial stretching, and the stress-strain curve can be transferred to the microscopic scale as mechanical properties. During the uniaxial stretching process, the stretching surface is coupled with the reference point RP. By assigning a displacement constraint at RP and outputting the curve of the model through the reference point, the displacement load is applied to the model at a uniform speed until the set value is reached, and the stress-strain curve is drawn synchronously. By converting the stress-strain curves of the microscopic fiber bundles and porous matrix, as well as the strength values, thermal expansion coefficients and yield points at the corresponding temperatures, the equivalent homogenization and performance transfer of the microscopic warp and weft yarns and equivalent matrix are completed.

[0060] For the microscopic model of performance degradation after thermal cycling, finite elements can be used to apply uniaxial or multiaxial tension along the longitudinal (x-axis) and latitudinal (y-axis) directions for progressive failure analysis, or to perform response analysis of multi-physics field loads according to service conditions.

[0061] S3: Multi-level homogenization and property transfer. In this multiscale model, the properties of the microfiber bundle are transferred to the microscale warp and weft yarns, and the properties of the microporous matrix are transferred to the microscale equivalent matrix. After homogenization and equivalentization, the micromodel is treated as the same homogeneous material phase in the mesoscale model. The transferred properties include thermophysical properties such as thermal conductivity, specific heat capacity, and thermal expansion coefficient; mechanical properties such as elastic modulus, yield stress, plastic strain, strength, and elongation at break; and other properties such as density, creep, viscosity, and damping. For heat transfer analysis and temperature fields, these material properties are temperature-dependent. These properties are generally extracted from finite element analysis curves of the micromodel, and the corresponding material constitutive model is selected for characterization and fitting. For the progressive failure analysis, the UMAT subroutine (User-Material) was written for ABAQUS using Python software. The porous matrix was characterized using a ductile fracture model, and the fiber bundles were characterized using the Hashin damage criterion.

[0062] Apply multi-physics loads. Select the required analysis method based on the structural service condition and apply loads. The following are relevant examples.

[0063] Working condition 1, heat transfer-thermal property analysis: There are two types of heat transfer analysis used in this example: steady-state and transient. In the macrostructure and microscopic models, the heat flux applied on the surface is conducted along the thickness until it reaches the bottom surface and produces a transient temperature rise; while the microscopic model is a unit cell, the time consumption of heat flux conduction can be ignored, and a stable temperature gradient is generated at any time. In order to meet the periodic boundary conditions, adiabatic boundaries are used on all sides of the model. Steady-state heat transfer analysis is performed on the microscopic fiber bundle and porous matrix models, and the obtained thermal properties in the orthogonal direction are assigned to each phase of the microscopic model; transient heat transfer analysis is performed on the microscopic model of the woven composite material to characterize the temperature field and thermal stress field of the macroscopic structure under service conditions after thermal cycling.

[0064] Working condition 2, multiaxial load-progressive failure analysis: establish a reference point on the microscopic model (including fiber bundles and porous matrix) and couple it with the loading surface, apply transverse / longitudinal tension and shear loads to the reference point respectively, and obtain stress-strain curves and corresponding failure modes. Due to the large differences in the transverse and longitudinal properties of the fiber bundle, it is necessary to perform failure analysis under combined stress to describe the progressive failure form of the macrostructure in a complex stress field. Couple the fiber bundles according to different loading paths (radial, orthogonal, and tortuous), such as applying multiaxial loads radially at a fixed combined strain ratio until it fails, and then output the mechanical response under different loading ratios and draw the failure envelope surface, and transfer the mechanical properties to the warp and weft yarns through the UMAT subroutine. Apply multiaxial loads to the microscopic woven composite material model, and use the subroutine to judge and correct the stiffness matrix, stress and damage state of the grid integration point to complete the progressive failure analysis.

[0065] Thermomechanical response analysis and design optimization under macrostructure service conditions. The results show that matrix cracking and interface debonding after thermal cycling lead to performance degradation and affect the stress field and temperature field of the macrostructure. Due to the difference in thermal expansion coefficients between the fiber and the matrix, the temperature change caused by the thermal cycle causes huge thermal stress at the interface. When the thermal stress at the pores exceeds the yield strength, the matrix produces plastic strain and has the following effects on the microstructure: 1. The dislocation substructure changes, accompanied by cyclic hardening or softening; 2. Microcracks occur in the matrix or develop into micropores; 3. Debonding and slip occur at the interface. The corresponding working condition results are as follows:

[0066] Case 1: Results demonstrate that the multiscale model can explain the linear, nonlinear, and quasi-linear phases of the stress-strain curve of a braided composite material under multiaxial tension, as well as the corresponding damage evolution. Fracture morphologies of the braided composite material include mesoscale matrix fragmentation and delamination, as well as microscale fiber breakage, fiber pullout, matrix cracking, and interfacial debonding. This method can reveal the damage evolution of materials under thermal cycling, the relationship between macroscopic loading and microscopic failure, and the failure mechanism of coupled multiaxial loading.

[0067] Case 2: Results show that the structural form significantly influences thermal properties and temperature fields. Fibers serve as the primary heat transfer pathways, with heat flow primarily conducted along the fibers or along the channels formed by their overlap. Porosity and manufacturing defects create thermal resistance, hindering heat flow. By adjusting the fiber / pore distribution and the 2D / 3D weaving pattern, heat transfer pathways can be designed and an effective heat transport network can be constructed, potentially redesigning the thermal insulation properties of composite materials.

[0068] Example 2:

[0069] A device for implementing a model construction and simulation method for a braided composite material, comprising:

[0070] The microstructure processing module is used to establish a fiber bundle model containing fibers, matrix, pores, and interfaces, and a porous matrix model containing pores and matrix. Structural parameters and material properties are assigned to the fiber bundle model and the porous matrix model based on existing material library data or observation data during the test process. By applying cyclic temperature fields and multi-physics field loads to the assigned fiber bundle model and the porous matrix model and extracting responses, the degradation of material properties related to elastic-plastic constitutive properties, high-temperature thermal properties, and fracture energy after thermal cycling is obtained. The fiber bundle model and the porous matrix model are homogenized into the material properties and transferred to the microstructure model.

[0071] The microstructure processing module is used to impart properties to homogenized fiber bundles and homogenized porous matrices. It applies the periodic boundary conditions and multi-physics field loads of the macrostructure's service conditions to the micromodel to obtain the thermo-mechanical response and performance degradation of the micromodel, as well as fatigue damage under cyclic loads, and completes progressive failure analysis. It also obtains the actual response of the macrostructure under multi-physics fields.

[0072] The judgment module is used to judge whether the damage variable is greater than 1; whether the stiffness value after degradation is zero; whether the stress value in the main direction of the material is higher than the strength value; and whether the amplitude of ductile deformation is lower than the fracture threshold.

[0073] Example 3:

[0074] A computer-readable storage medium stores a computer program, wherein when the computer program is executed by a processor, the device where the computer-readable storage medium is located executes a model construction and simulation method for a woven composite material.

[0075] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.

Claims

1. A model construction and simulation method for braided composite materials, characterized in that , including the following steps: S1: Establish a fiber bundle model containing fibers, matrix, pores, and interfaces, and a porous matrix model containing pores and matrix, respectively, at the microscale of the woven composite material. Assign material properties to the fiber bundle model and the porous matrix model based on existing material library data or observation data during the test process. Based on the observation results, assign structural parameters at the microscale to complete the construction of the multi-scale model. S2: By applying multi-physics field loads transferred from the microscopic model to the fiber bundle model and porous matrix model after the material properties are assigned, and extracting the response, the material performance degradation related to elastic-plastic constitutive properties, high-temperature thermal properties, and fracture energy is obtained; the performance of the microscopic model is equivalent to a thermo-mechanical response curve, which is then homogenized and transferred to the homogenized fiber bundle and homogenized porous matrix in the microscopic woven composite material model; S3: Assign properties to homogenized fiber bundles and porous matrices at the microscale of woven composites; convert the service conditions of the macrostructure into loads and boundary conditions, apply them to the microscopic model, calculate the multi-physics field response as loads, and transfer it to the microscopic model; After updating the thermo-mechanical response, the performance degradation of the micro-model and the fatigue damage under cyclic loading are obtained, and the progressive failure analysis is completed; the actual response of the macro-structure under multi-physics fields is obtained; The imparting of properties to the uniform fiber bundles and the uniform porous matrix on the microscopic scale of the woven composite material specifically includes the following steps: Q1: Based on the ABAQUS solver, the strain field of the braided composite material is obtained through the finite element model, and the initial stress field of the braided composite material is calculated based on the stiffness matrix constructed by the mesh nodes; Q2: The initial stress fields of the warp / weft yarns and the equivalent matrix are calculated using the microscopic model. These are then processed into step Q3 for homogenized fiber bundles and step Q4 for homogenized porous matrix to perform failure judgment and stress update. Q3: Based on the ratio of stress to strength in the principal direction of the material, calculate the sum obtained by weighted average and determine whether the damage variable is greater than 1. If so, proceed to step Q3.1; if not, proceed to step Q5; Q3.1: Degrade the stiffness of the homogenized fiber bundle along the linear decline curve according to the strain value. Determine whether the degraded stiffness value is zero based on the fracture energy data. If so, perform integration point failure and mesh deletion operations and proceed to step Q5; if not, proceed to step Q5; Q4: Determine whether the stress value in the main direction of the material is higher than the strength value. If so, go to step Q4.1; if not, go to step Q5; Q4.1: Calculate the magnitude of ductile deformation of the homogenized porous matrix using the material constitutive model for ductile fracture and determine whether the magnitude is below the fracture threshold. If so, proceed to step Q5. If not, fracture the homogenized porous matrix, perform integration point failure and mesh deletion, and proceed to step Q5. Q5: Update the stress field, strain field and overall stiffness matrix of woven composite materials.

2. The model construction and simulation method of a braided composite material according to claim 1, characterized in that: The structural parameters in step S1 include the diameter, aspect ratio, volume fraction, distribution mode of the fibers and the median pore size, shape, distribution mode, porosity of the pores at the microscopic scale, as well as the weaving density / bundle / cm, linear density / tex, and weaving mode of the warp and weft yarns at the microscopic scale; the material properties include the mechanical and thermal properties of the initial matrix phase, interface phase, and fiber phase.

3. The model construction and simulation method of a braided composite material according to claim 1, characterized in that: The multi-physics field load in step S2 includes stress-strain field load, heat flow load, and temperature load.

4. The model construction and simulation method of a braided composite material according to claim 1, characterized in that: The high-temperature thermal properties in step S2 include thermal expansion coefficient, thermal conductivity, specific heat capacity, and thermal diffusivity at different temperatures.

5. The model construction and simulation method of a braided composite material according to claim 1, characterized in that: The progressive failure analysis in step S3 includes three parts: stress analysis, failure analysis, and material degradation.

6. A device for implementing the model building and simulation method of a braided composite material according to any one of claims 1 to 5, characterized in that: include: The microstructure processing module is used to establish a fiber bundle model containing fibers, matrix, pores, and interfaces, and a porous matrix model containing pores and matrix. Structural parameters and material properties are assigned to the fiber bundle model and the porous matrix model based on existing material library data or observation data during the test process. By applying cyclic temperature fields and multi-physics field loads to the assigned fiber bundle model and the porous matrix model and extracting responses, the degradation of material properties related to elastic-plastic constitutive properties, high-temperature thermal properties, and fracture energy after thermal cycling is obtained. The fiber bundle model and the porous matrix model are homogenized into the material properties and transferred to the microstructure model. The microstructure processing module is used to impart properties to homogenized fiber bundles and porous matrices. The periodic boundary conditions and multi-physics field loads of the macrostructure service conditions are applied to the microstructure model to obtain the thermo-mechanical response and performance degradation of the microstructure, as well as the fatigue damage under cyclic loads, and complete the progressive failure analysis. The actual response of the macrostructure under multi-physics fields is obtained. The judgment module is used to judge whether the damage variable is greater than 1; whether the stiffness value after degradation is zero; whether the stress value in the main direction of the material is higher than the strength value; and whether the amplitude of ductile deformation is lower than the fracture threshold.

7. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the device where the computer-readable storage medium is located executes the method according to any one of claims 1 to 5.

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