Multi-scale analysis method, system and equipment for damage failure of hybrid fiber composite material and storage medium

Abstract

The invention provides a multi-scale analysis method, system and equipment for damage failure of a hybrid fiber composite material and a storage medium, and the method comprises the steps: obtaining microscopic-macroscopic stress amplification coefficient linear equations corresponding to a first fiber, a second fiber and a matrix in different damage states of the matrix from a microscopic scale by means of a microscopic scale; further obtaining microscopic stress according to the macroscopic stress, judging whether damage failure occurs or not and whether damage evolution is performed or not based on the microscopic stress, and correspondingly, introducing macroscopic damage variables to realize the influence of the microscopic scale on the macroscopic scale when the damage failure occurs; further, the macroscopic stiffness matrix can be updated in real time along with the continuous change of different component states under the microscale, so that the damage failure mode of the hybrid fiber composite material in the woven layer is researched.

Description

Technical Field

[0001] The present invention belongs to the technical field of mechanical property evaluation of composite materials, and relates to a multi-scale analysis method, system, device and storage medium for damage and failure of hybrid fiber composite materials. Background Technique

[0002] Carbon fiber reinforced composite materials (CFRP) have been gradually introduced into the lightweight design of vehicle bodies due to their good mechanical properties and unique lightweight effect. However, the current high cost of carbon fiber restricts its large-scale application in the automotive industry. In addition, the poor toughness of carbon fiber may cause brittle fracture failure modes when the vehicle body components are subjected to impact loads, ultimately leading to a significant reduction in the vehicle body collision safety performance. To address the bottleneck problems of CFRP in the lightweight design of vehicle bodies, if low-cost and high-toughness composite materials are combined with CFRP, and the hybrid ratio and hybrid method are reasonably set, not only can the structural performance of the vehicle body be improved, but also the vehicle body self-weight can be significantly reduced, with a good lightweight effect, meeting the requirements of cost reduction and efficiency improvement. Accordingly, the design concept of a hybrid fiber composite material (HFRP) vehicle body structure has emerged. However, HFRP has a high degree of non-linearity and many influencing factors on mechanical properties. If only relying on experimental methods for structural design, not only is the cost too high and the cycle too long, but also it cannot meet the actual engineering requirements. Numerical simulation technology must play an important role in its structural design. Currently, the numerical models available for mechanical simulation of hybrid fiber composite materials can be roughly divided into three categories: micro-mechanical models, macro-mechanical models, and multi-scale models. Micro-mechanical models analyze the generation of component material fractures and crack propagation from the micro-scale composed of fibers and matrices. This model requires a large amount of computing resources and is not suitable for the development and design of large components. Therefore, it has not been popularized in engineering applications at present. Macro-mechanical models simplify the micro-material model into an anisotropic homogeneous material, which can more accurately predict the overall mechanical response of the structure, but cannot analyze the influence law of characteristic parameters at the micro-scale on the component performance.

[0003] To overcome the above drawbacks, some scholars have proposed a multi-scale modeling technique for composite materials based on localization and homogenization methods. By establishing microscopic models, mesoscopic models, and macroscopic models, the multi-scale characteristic parameters of composite materials are correlated with product performance. Currently, most multi-scale models can only transfer elastic and strength characteristics to corresponding meso-mechanics or macro-mechanics models, and these multi-scale models are widely used in structural stiffness analysis. However, for the crashworthiness design of composite thin-walled structures, it is usually necessary to consider the initiation and evolution of material damage. Traditional multi-scale models usually cannot obtain macroscopic material damage parameters through their microscopic and mesoscopic models, resulting in the separation of macroscopic material damage and failure from their microscopic characteristics and being unable to meet the multi-scale design requirements of component crashworthiness. Therefore, developing a microscopic-mesoscopic-macroscopic multi-scale analysis method for hybrid fiber composite materials is of great significance for studying the damage and failure modes of hybrid fiber composite materials. Summary of the Invention

[0004] To solve the problems of the above-mentioned existing technologies, the present invention provides a multi-scale analysis method, system, device, and storage medium for damage and failure of hybrid fiber composite materials. Starting from the microscopic scale and with the aid of the mesoscopic scale, it studies the damage and failure modes of woven hybrid fiber composite materials within a layer, providing a new strategy for the design and optimization of HFRP structures.

[0005] The present invention is realized through the following technical solutions: In a first aspect, the present invention provides a multi-scale analysis method for damage and failure of hybrid fiber composite materials, including: S1, establishing a first fiber microscopic unit cell model and a second fiber microscopic unit cell model of the hybrid fiber composite material and assigning the material properties of the first fiber filament, the second fiber filament, and the matrix; establishing a hybrid fiber mesoscopic unit cell model; S2, applying a concentrated unit load to the first fiber microscopic unit cell model, the second fiber microscopic unit cell model, and the hybrid fiber mesoscopic unit cell model respectively, extracting the stress, and calculating the microscopic-macroscopic stress amplification coefficients corresponding to the first fiber, the second fiber, and the matrix respectively; S3, reducing the material properties of the matrix, repeating S2, and then fitting to obtain the linear equations of the matrix reduction coefficients corresponding to the first fiber, the second fiber, and the matrix respectively and the microscopic-macroscopic stress amplification coefficients; S4, establishing a macroscopic model of the hybrid fiber composite material, assigning the elastic modulus of the hybrid fiber composite material, performing a three-point bending test simulation, and calculating the macroscopic stresses corresponding to the first fiber, the second fiber, and the matrix respectively according to the macroscopic stiffness matrix of the macroscopic model; S5. Calculate the microscopic stresses corresponding to the first fiber, the second fiber, and the matrix respectively based on the macroscopic stress obtained from S4 and the linear equation obtained from S3. Determine whether the first fiber, the second fiber, and the matrix satisfy the failure criterion according to the microscopic stresses. If at least one component satisfies the failure criterion, calculate the elastic modulus of the component after damage reduction at the microscopic scale based on the microscopic stress corresponding to the component that satisfies the failure criterion; otherwise, proceed to S7. S6. Calculate the macroscopic damage variable based on the elastic modulus after damage reduction, and update the macroscopic stiffness matrix according to the macroscopic damage variable. S7. Iterate the increment step and return to S4, where the increment step is the increment of the matrix reduction coefficient.

[0006] Preferably, S1 includes: S11. Obtain the volume fractions of the first fiber filaments and the second fiber filaments at the microscopic scale and the volume fractions of the first fiber bundles and the second fiber bundles at the mesoscopic scale in the hybrid fiber composite material. Respectively establish a first fiber microscopic unit cell model, a second fiber microscopic unit cell model, and a hybrid fiber mesoscopic unit cell model without pores according to the obtained volume fractions. S12. Randomly select a preset proportion of matrix grid cells in all matrix grid cells of the first fiber microscopic unit cell model, the second fiber microscopic unit cell model, and the hybrid fiber mesoscopic unit cell model without pores, and simulate pores with the selected matrix grid cells to obtain the first fiber microscopic unit cell model, the second fiber microscopic unit cell model, and the hybrid fiber mesoscopic unit cell model containing pores. Assign the material properties of the first fiber, the second fiber, and the matrix to the first fiber microscopic unit cell model and the second fiber microscopic unit cell model.

[0007] Preferably, S2 specifically includes: S21. Apply periodic boundary conditions to the first fiber microscopic unit cell model and the second fiber microscopic unit cell model respectively, apply six different working conditions of concentrated unit loads, and calculate the elastic mechanical parameters of the first fiber bundle and the second fiber bundle respectively. Assign the elastic mechanical parameters of the first fiber bundle and the second fiber bundle to the hybrid fiber mesoscopic unit cell model, apply periodic boundary conditions, apply six different working conditions of concentrated loads, and calculate the elastic modulus of the hybrid fiber composite material. S22. When applying a concentrated unit load, extract the stresses of the first fiber grid elements, the second fiber grid elements, and the matrix grid elements in the first fiber microscopic unit cell model, the second fiber microscopic unit cell model, and the hybrid fiber mesoscopic unit cell model under different working conditions. According to the obtained stresses and through cluster analysis, select reference points. By calculating the stress amplification factors of the reference points, respectively obtain the microscopic-mesoscopic stress amplification factors corresponding to the first fiber, the second fiber, and the matrix, as well as the mesoscopic-macroscopic stress amplification factors corresponding to the first fiber, the second fiber, and the matrix. Multiply the microscopic-mesoscopic stress amplification factors by the corresponding mesoscopic-macroscopic stress amplification factors to obtain the microscopic-macroscopic stress amplification factors corresponding to the first fiber, the second fiber, and the matrix respectively.

[0008] Further, S22 specifically includes: S221. After applying concentrated loads under six different working conditions to the first fiber microscopic unit cell model, respectively extract the stresses of the first fiber grid elements and the matrix grid elements in the first fiber microscopic unit cell model in six directions. Each grid element obtains a stress amplification factor matrix in the form of 6×6. S222. Convert the stress amplification factor matrix into a 1×36 matrix ; S223. Respectively arrange the matrices of all the first fiber grid elements and all the matrix grid elements in the first fiber microscopic unit cell model into a matrix B , and the number of rows of the matrix B is equal to the total number of grid elements in the corresponding component; S224. Conduct cluster analysis on the matrices B corresponding to the first fiber and the matrix respectively, take the obtained cluster centers as reference points, and based on the reference points, obtain the microscopic-mesoscopic stress amplification factors corresponding to the first fiber and the matrix in the first fiber microscopic unit cell model; S225. According to the methods of S221 - S224, obtain the microscopic-mesoscopic stress amplification factors corresponding to the second fiber and the matrix in the second fiber microscopic unit cell model, as well as the mesoscopic-macroscopic stress amplification factors corresponding to the first fiber, the second fiber, and the matrix in the hybrid fiber mesoscopic unit cell model; Combine the microscopic-mesoscopic stress amplification factors corresponding to the matrix in the first fiber microscopic unit cell model and the microscopic-mesoscopic stress amplification factors corresponding to the matrix in the second fiber microscopic unit cell model to obtain the microscopic-mesoscopic stress amplification factors corresponding to the matrix; S226, multiply the microscopic-mesoscopic stress amplification factor corresponding to the first fiber by the mesoscopic-macroscopic stress amplification factor corresponding to the first fiber, multiply the microscopic-mesoscopic stress amplification factor corresponding to the second fiber by the mesoscopic-macroscopic stress amplification factor corresponding to the second fiber, and multiply the microscopic-mesoscopic stress amplification factor corresponding to the matrix by the mesoscopic-macroscopic stress amplification factor corresponding to the matrix, to obtain the microscopic-macroscopic stress amplification factors corresponding to the first fiber, the second fiber, and the matrix respectively.

[0009] Preferably, S3 specifically includes: S31. Set the reduction coefficients of the first fiber and the second fiber in the first fiber microscopic unit cell model, the second fiber microscopic unit cell model, and the mesoscopic unit cell model to 0, and set the reduction coefficients of the matrix to 0, 0.1, 0.3, 0.6, and 0.9 respectively. Reduce the material properties of the matrix, repeat S2, and calculate the microscopic-macroscopic stress amplification factors corresponding to the first fiber, the second fiber, and the matrix respectively under different damage states of the matrix; S32. Using the reduction coefficient of the matrix as the independent variable and the microscopic-macroscopic stress amplification factors corresponding to the first fiber, the second fiber, and the matrix respectively as the dependent variables, fit a linear equation to obtain the linear equations of the reduction coefficient of the matrix and the microscopic-macroscopic stress amplification factors corresponding to the first fiber, the second fiber, and the matrix respectively when the first fiber and the second fiber are undamaged; S33. Set the reduction coefficients of the first fiber and the second fiber to 0.9, repeat S31 and S32, calculate the microscopic-macroscopic stress amplification factors corresponding to the first fiber, the second fiber, and the matrix respectively under different damage states of the matrix and fit a linear equation to obtain the linear equations of the reduction coefficient of the matrix and the microscopic-macroscopic stress amplification factors corresponding to the first fiber, the second fiber, and the matrix respectively when the first fiber and the second fiber are damaged.

[0010] Preferably, in S5, the failure criteria for the first fiber and the second fiber are:

[0011]

[0012] In the formula, represents the microscopic stress of the first fiber filament / second fiber filament along the longitudinal direction at the microscopic scale, represents the initial tensile strength of the first fiber filament / second fiber filament, represents the initial compressive strength of the first fiber filament / second fiber filament; if the calculated and values are greater than or equal to 1, then the first fiber filament / second fiber filament undergoes damage failure; The failure criterion for the matrix is:

[0013]

[0014] In the formula, and respectively represent the Von-Mises stress value and the critical Von-Mises stress value of the matrix; and respectively represent the first stress invariant of the matrix and the critical first stress invariant of the matrix; and respectively represent the initial tensile strength of the matrix and the initial compressive strength of the matrix; , and respectively represent the microscopic stresses in six directions of the reference point on the matrix. The subscript 1 corresponds to the x-axis, 2 corresponds to the y-axis, and 3 corresponds to the z-axis. When the value of

[0015] is greater than or equal to 1, damage failure of the matrix occurs. Preferably, S6 specifically includes:

[0016]

[0017] In the formula, , and respectively represent the elastic moduli of the hybrid fiber composite material in the x-direction, y-direction, and z-direction at the macroscopic scale; , and respectively represent the volume fractions of the first fiber, the second fiber, and the matrix at the microscopic scale; V f is the sum of the volume fractions of the first fiber and the second fiber; , and respectively represent the macroscopic damage variables of the hybrid fiber composite material in the x-direction, y-direction, and z-direction at the macroscopic scale. The superscripts T and C respectively represent tension and compression; and respectively are the elastic moduli along the longitudinal direction after damage reduction of the first fiber filament and the second fiber filament at the microscopic scale; is and sum, and respectively are the elastic moduli along the transverse direction after damage reduction of the first fiber filament and the second fiber filament at the microscopic scale; represents the elastic modulus of the matrix after damage reduction at the microscopic scale; Update the macroscopic stiffness matrix: The calculated macroscopic damage variable is multiplied by the initial stiffness matrix at the macroscopic scale to obtain the macroscopic stiffness matrix.

[0018] In a second aspect, the present invention provides a multi-scale analysis system for damage and failure of hybrid fiber composites, including: A model construction module for establishing a first fiber microscopic unit cell model and a second fiber microscopic unit cell model of the hybrid fiber composite and assigning material properties to the first fiber filaments, the second fiber filaments, and the matrix; establishing a hybrid fiber mesoscopic unit cell model; A unit cell model simulation module for respectively applying concentrated unit loads to the first fiber microscopic unit cell model, the second fiber microscopic unit cell model, and the hybrid fiber mesoscopic unit cell model, extracting stresses, and calculating the microscopic-macroscopic stress amplification factors corresponding to the first fiber, the second fiber, and the matrix respectively; reducing the material properties of the matrix to obtain the microscopic-macroscopic stress amplification factors corresponding to the first fiber, the second fiber, and the matrix respectively under different damage states of the matrix, and fitting linear equations of the matrix reduction factors and the microscopic-macroscopic stress amplification factors corresponding to the first fiber, the second fiber, and the matrix respectively; A macroscopic model construction module for establishing a macroscopic model of the hybrid fiber composite and assigning the elastic modulus of the hybrid fiber composite; A failure simulation module for simulating a three-point bending test on the macroscopic model, calculating the macroscopic stresses corresponding to the first fiber, the second fiber, and the matrix respectively according to the macroscopic stiffness matrix of the macroscopic model; calculating the microscopic stresses corresponding to the first fiber, the second fiber, and the matrix respectively according to the macroscopic stresses and the linear equations; judging whether the first fiber, the second fiber, and the matrix meet the failure criteria according to the microscopic stresses. If at least one component meets the failure criteria, calculating the elastic modulus of the component after damage reduction at the microscopic scale according to the microscopic stress corresponding to the component that meets the failure criteria, calculating the macroscopic damage variable according to the elastic modulus after damage reduction, updating the macroscopic stiffness matrix according to the macroscopic damage variable, and iterating the increment step. Otherwise, directly iterating the increment step; the increment step is the increment of the matrix reduction factor.

[0019] In a third aspect, the present invention provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the multi-scale analysis method for damage and failure of hybrid fiber composites as described above.

[0020] In a fourth aspect, the present invention provides a computer-readable storage medium storing a computer program, and when the computer program is executed by a processor, it implements the multi-scale analysis method for damage and failure of hybrid fiber composites as described above.

[0021] Compared with the prior art, the present invention has the following beneficial effects: Based on the micro-mechanical damage theory (MMF), the present invention establishes a set of micro-meso-macro multi-scale hybrid fiber composite material collaborative design methods. Starting from the micro-scale, with the help of the meso-scale, the linear equations of the micro-macro stress amplification coefficients corresponding to the first fiber, the second fiber, and the matrix under different damage states of the matrix are obtained. Then, based on the macro stress, the micro stress is obtained, and based on the micro stress, it is judged whether damage failure occurs and whether damage evolution is carried out. When damage failure occurs, by introducing the macro damage variable, the influence of the micro-scale on the macro-scale is realized, and thus the macro stiffness matrix can be updated in real time as the different component states at the micro-scale change continuously, so as to study the damage failure mode of the woven in-layer hybrid fiber composite material, providing a new strategy for the design and optimization of the HFRP structure.

[0022] Furthermore, the present invention takes into account the influence of porosity on the elastic mechanical parameters of the structure, making the predicted results more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0024] Figure 1 is a flowchart of the multi-scale analysis of the woven hybrid fiber composite material; Figure 2 is a cross-sectional morphology diagram of the in-layer hybrid fiber composite material sample; Figure 3 is a microscopic unit cell model diagram containing pores; Figure 4 is a mesoscopic unit cell model diagram containing pores; Figure 5 is a simplified model diagram of the periodic boundary conditions of the unit cell model; Figure 6 is a comparison diagram of multi-scale simulation and experimental results. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The following specifically illustrates the embodiments of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and 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 invention.

[0026] It should be noted that the process equipment or devices not specifically specified in the following embodiments all adopt conventional equipment or devices in the art.

[0027] It should be noted that the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or devices. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool for identifying each method step, rather than limiting the arrangement order of each method step or the scope in which the present invention can be implemented. The change or adjustment of their relative relationship, without substantial change in the technical content, should also be regarded as the scope in which the present invention can be implemented.

[0028] Embodiment This embodiment provides a multi-scale analysis method for the micro-damage failure of hybrid fiber composites. Taking the laminate of plain woven carbon-glass hybrid fiber composites as an example below, the above method is used for multi-scale analysis ( Figure 1 ). In this embodiment, the first fiber is carbon fiber and the second fiber is glass fiber.

[0029] Step 1: Calculate the volume fractions of carbon fiber filaments and glass fiber filaments at the microscale and the volume fractions of carbon fiber bundles and glass fiber bundles at the mesoscale in the hybrid fiber composite through electron microscopy scanning tests. The distribution forms of carbon fiber filaments, glass fiber filaments, carbon fiber bundles, and glass fiber bundles are as Figure 2 shown. Respectively establish a carbon fiber microcell model without pores, a glass fiber microcell model without pores, and a hybrid fiber mesocell model without pores. Step 2: Randomly select a certain proportion of matrix grid cells in all matrix grid cells of the carbon fiber microcell model, the glass fiber microcell model, and the hybrid fiber mesocell model, and endow these matrix grid cells with the material properties of air to simulate pores, obtaining a carbon fiber microcell model containing pores, a glass fiber microcell model as Figure 3 shown, and a hybrid fiber mesocell model containing pores as Figure 4 shown.

[0030] Step 201: In the established carbon fiber microcell model, glass fiber microcell model, or hybrid fiber mesocell model, respectively establish sets to save the fiber grid cells and matrix grid cells, obtain a set of matrix grid cells, and export an input file.

[0031] Step 202: Locate the created matrix mesh element set in the exported input file, copy all the matrix mesh element numbers to EXCEL, and use a random function to select the required proportion of elements.

[0032] Step 203: Manually edit and establish a pore set in the input file, and input the matrix mesh element numbers randomly selected in Step 202 into the pore set.

[0033] Step 204: Import the input file into ABAQUS software, assign material properties to the fiber mesh elements and matrix mesh elements, and obtain a carbon fiber microscopic unit cell model, a glass fiber microscopic unit cell model, or a hybrid fiber mesoscopic unit cell model containing pores.

[0034] Step 3: Refer to Figure 5 the schematic diagram of applying periodic boundary conditions to the shown unit cell model, apply periodic boundary conditions to the microscopic unit cell model and the mesoscopic unit cell model, load six different concentrated unit load conditions, and predict the elastic mechanical parameters of the mesoscopic fiber bundle and the macroscopic laminate.

[0035] For plain weave fabrics, their structure is only periodic in the xy plane and not periodic in the thickness direction z. After simplifying the smallest unit cell model into a cube model and applying periodic boundary conditions, predict the elastic mechanical parameters. The specific steps are as follows: Step 301: Assign the material properties of fiber filaments and matrix to the carbon fiber microscopic unit cell model and the glass fiber microscopic unit cell model, and apply periodic boundary conditions: (a) Eliminate the rigid body displacement by constraining the degrees of freedom of the four vertices A, D, C, and H. The translational displacements of point D in the x, y, and z directions are all constrained, and the rotational degrees of freedom are released; the translational displacement of point H in the x direction is constrained; the translational displacement of point A in the y direction is constrained; the translational displacement of point C in the z direction is constrained.

[0036] (b) Define x = 0 and y = 0 as the master planes, while x = a and y = b are regarded as the slave planes. The points on the master plane and the slave plane are called the master nodes and the slave nodes respectively. When constraining the nodes on the parallel planes, the displacement difference between the projections of the master nodes and the slave nodes on the coordinate axes always remains a constant value.

[0037] (c) When constraining the nodes on the plane, it is found that the nodes on the four free edges 9, 10, 11, and 12 are both master nodes and slave nodes. If finite element analysis is performed, they will not be recognized and an error will occur. Therefore, it is necessary to constrain the four edges separately.

[0038] (d) After constraining the nodes on the plane, not only will there be problems with the master and slave nodes on the edges, but also with the four free vertices B, E, F, and G. Therefore, they also need to be constrained separately.

[0039] Step 302: Apply concentrated unit loads to the carbon fiber microscopic unit cell model and the glass fiber microscopic unit cell model respectively , , , , , Six different working conditions of concentrated unit loads are applied, and the elastic mechanical parameters (elastic modulus and shear modulus) of the carbon fiber bundle and the glass fiber bundle are obtained through the following calculations: = , = - , = - (1) = , = - , = - (2) = , = - , = - (3) = (4) = (5) = (6) (7) Among them, represents the average strain of the node under the concentrated unit load of represents the average strain of the node under the concentrated unit load of represents the average strain of the node under the concentrated unit load of represents the average strain of the node under the concentrated unit load of represents the average strain of the node under the concentrated unit load of Represents The average strain of the node under a concentrated unit load, Represents the fiber bundle at The elastic modulus under a concentrated unit load, Represents the fiber bundle at The elastic modulus under a concentrated unit load, Represents the fiber bundle at The elastic modulus under a concentrated unit load, Represents the fiber bundle at The shear modulus under a concentrated unit load, Represents the fiber bundle at The shear modulus under a concentrated unit load, Represents the fiber bundle at The shear modulus under a concentrated unit load, Represents the fiber bundle at The shear modulus under a concentrated unit load, Represents the Poisson's ratio between the y-axis direction and the x-axis direction, Represents the Poisson's ratio between the y-axis direction and the x-axis direction, Represents the Poisson's ratio between the y-axis direction and the x-axis direction, Represents the Poisson's ratio between the z-axis direction and the x-axis direction, Represents the Poisson's ratio between the x-axis direction and the y-axis direction, Represents the Poisson's ratio between the z-axis direction and the y-axis direction, Represents the Poisson's ratio between the x-axis direction and the y-axis direction, Represents the Poisson's ratio between the y-axis direction and the z-axis direction. a represents the length of the carbon fiber microcell model or the glass fiber microcell model in the x-axis direction, b represents the length of the carbon fiber microcell model or the glass fiber microcell model in the y-axis direction, and c represents the length of the carbon fiber microcell model or the glass fiber microcell model in the z-axis direction. Represents the displacement value of node C on the x-axis, Represents the displacement value of node A on the z-axis, Represents the displacement value of node H on the y-axis, Represents the displacement value of node C on the z-axis, Represents the displacement value of node A on the z-axis, Represents the displacement value of node H on the y-axis.

[0040] Step 303: Assign the elastic mechanical parameters of the carbon fiber bundle and the glass fiber bundle obtained in Step 302 to the hybrid fiber mesoscopic cell model, and apply periodic boundary conditions.

[0041] Step 304: Apply concentrated unit loads under six different working conditions to the meso-unite cell model of hybrid fibers, and predict the elastic mechanical parameters of the macro laminate, including the elastic moduli in the x-direction, y-direction, and z-direction, denoted as , and , and the method is the same as that in Step 302.

[0042] Step 4: Extract the stresses of carbon fiber grid elements and matrix grid elements in the carbon fiber micro-unite cell model under different working conditions, perform clustering analysis using the K-means clustering method, respectively select the reference points of carbon fibers and the matrix, and calculate the microscopic-meso stress amplification factors corresponding to carbon fibers and the matrix; use the same method to calculate the microscopic-meso stress amplification factors corresponding to glass fibers and the matrix for the glass fiber micro-unite cell model; combine the microscopic-meso stress amplification factors corresponding to the matrix obtained from the carbon fiber micro-unite cell model and the glass fiber micro-unite cell model to obtain the unified microscopic-meso stress amplification factor corresponding to the matrix; for the meso-unite cell model of hybrid fibers, extract the stresses of carbon fiber grid elements, glass fiber grid elements, and matrix grid elements under different working conditions, perform clustering analysis using the K-means clustering method, respectively select the reference points of carbon fibers, glass fibers, and the matrix, and calculate the meso-macro stress amplification factors corresponding to carbon fibers, glass fibers, and the matrix; multiply the microscopic-meso stress amplification factor corresponding to carbon fibers by the meso-macro stress amplification factor corresponding to carbon fibers to obtain the microscopic-macro stress amplification factor corresponding to carbon fibers; use the same method to obtain the microscopic-macro stress amplification factor corresponding to glass fibers and the microscopic-macro stress amplification factor corresponding to the matrix.

[0043] Step 401: After applying concentrated unit loads under six different working conditions to the carbon fiber micro-unite cell model, use ABAQUS to extract the stresses in 6 directions of carbon fiber grid elements and matrix grid elements in the carbon fiber micro-unite cell model respectively. There are 36 stress values for each grid element, and a stress amplification factor matrix in the form of 6×6 is obtained. The loads applied in Step 3 are all unit loads, that is, the macro stresses are all 1, and the microscopic stress = macro stress * stress amplification factor. Since the macro stress is 1, the value of the microscopic stress is the value of the stress amplification factor. Therefore, the stress amplification factor matrix can be obtained by extracting the stress values of each grid element.

[0044] Step 402: Convert the stress amplification factor matrix of each carbon fiber grid element or matrix grid element into a 1×36 matrix through MATLAB software , and the matrix is in the following form: (8) In the formula,i indicating the i th carbon fiber mesh unit or matrix mesh unit.

[0045] Step 403: Arrange the stress amplification factors of all carbon fiber mesh units and all matrix mesh units in the carbon fiber microcell model into a new matrix B to obtain matrices corresponding to carbon fiber and matrix respectively B ; the number of rows of matrix B is equal to the total number of mesh units in the corresponding component, and the form of matrix B is as follows: (9) Step 404: The software SPSS integrates the theory of the k-means clustering analysis method. Import the matrices B corresponding to carbon fiber and matrix respectively into the software SPSS, select the number k of clusters, select the number of iterations. After the iteration is completed, the values of each cluster center can be obtained. As shown in the following formula, convert the values of the cluster centers into the form of a stress amplification factor matrix through the MATLAB software.

[0046] (10) In the formula, represents the average value of the stress amplification factors of all units in the J th class.

[0047] Take the cluster centers as reference points to obtain the micro-meso stress amplification factors corresponding to carbon fiber and the micro-meso stress amplification factors corresponding to matrix in the carbon fiber microcell model respectively.

[0048] Step 405: Using the same method as steps 401 - 404 above, obtain the micro-meso stress amplification factors corresponding to glass fiber and the micro-meso stress amplification factors corresponding to matrix in the glass fiber microcell model, and the meso-macro stress amplification factors corresponding to carbon fiber, the meso-macro stress amplification factors corresponding to glass fiber, and the meso-macro stress amplification factors corresponding to matrix in the hybrid fiber mesocell model. Combine the micro-meso stress amplification factors corresponding to matrix in the carbon fiber microcell model and the micro-meso stress amplification factors corresponding to matrix in the glass fiber microcell model to obtain the micro-meso stress amplification factors corresponding to matrix.

[0049] Step 406: Multiply the microscopic-mesoscopic stress amplification factor corresponding to carbon fiber by the mesoscopic-macroscopic stress amplification factor corresponding to carbon fiber, multiply the microscopic-mesoscopic stress amplification factor corresponding to glass fiber by the mesoscopic-macroscopic stress amplification factor corresponding to glass fiber, and multiply the microscopic-mesoscopic stress amplification factor corresponding to the matrix by the mesoscopic-macroscopic stress amplification factor corresponding to the matrix, so as to obtain the microscopic-macroscopic stress amplification factors corresponding to carbon fiber, glass fiber, and the matrix respectively.

[0050] Step 5: Reduce the material properties of carbon fiber, glass fiber, and the matrix in advance to simulate damage. Repeat Step 3 and Step 4 to obtain the microscopic-macroscopic stress amplification factors under different damage states. Take the reduction coefficient of the matrix as the independent variable of the fitting equation, and use the linear fitting method to fit the linear equation of the stress amplification factor of the matrix under different damage states.

[0051] Step 501: Set the reduction coefficients of carbon fiber and glass fiber in the carbon fiber microscopic unit cell model, glass fiber microscopic unit cell model, and mesoscopic unit cell model to 0, and set the reduction coefficient of the matrix to 0, 0.1, 0.3, 0.6, 0.9. Then reduce the material properties of the matrix. Repeat Step 3 and Step 4 to calculate the microscopic-macroscopic stress amplification factors corresponding to carbon fiber, glass fiber, and the matrix respectively under different damage states of the matrix.

[0052] Step 502: Write a program using MATLAB. Take the reduction coefficient of the matrix as the independent variable, and the microscopic-macroscopic stress amplification factors corresponding to carbon fiber, glass fiber, and the matrix respectively as the dependent variables, and fit the linear equation to obtain the linear equations of the reduction coefficient of the matrix and the microscopic-macroscopic stress amplification factors corresponding to carbon fiber, glass fiber, and the matrix respectively when carbon fiber and glass fiber are undamaged.

[0053] Step 503: Adopt the maximum stress criterion for carbon fiber and glass fiber, and set the reduction coefficients of carbon fiber and glass fiber to 0.9. Repeat Step 501 and Step 502 to calculate the microscopic-macroscopic stress amplification factors corresponding to carbon fiber, glass fiber, and the matrix respectively under different damage states of the matrix and fit the linear equation, so as to obtain the linear equations of the reduction coefficient of the matrix and the microscopic-macroscopic stress amplification factors corresponding to carbon fiber, glass fiber, and the matrix respectively when carbon fiber and glass fiber are damaged under different damage states of the matrix.

[0054] Step 6: Write the fitted linear equation of the stress amplification factor, as well as the damage failure judgment criterion and damage evolution criterion of the fiber and the matrix, into the VUMAT subroutine to realize that the macroscopic stiffness matrix of the macroscopic model can be updated in real time as the different component states at the microscopic scale change continuously.

[0055] Step 601: Select the maximum stress failure criterion for the damage failure judgment of carbon fiber filaments / glass fiber filaments at the microscopic scale: (11) (12) In the formula, represents the microscopic stress of carbon fiber filaments / glass fiber filaments along the longitudinal direction at the microscopic scale, represents the initial tensile strength of carbon fiber filaments / glass fiber filaments, represents the initial compressive strength of carbon fiber filaments / glass fiber filaments. If the calculated through the microscopic stress and values are greater than or equal to 1, the carbon fiber filaments / glass fiber filaments are damaged and fail. The initial tensile strength and initial compressive strength are obtained through experiments.

[0056] Step 602: The damage failure mode of carbon fiber filaments / glass fiber filaments is mostly brittle fracture failure. Therefore, the damage evolution of carbon fiber filaments / glass fiber filaments adopts a direct reduction method. The present invention stipulates that the reduction coefficient of carbon fiber filaments / glass fiber filaments is 0.9, and the Poisson's ratio does not change. The damage evolution formula of carbon fiber filaments / glass fiber filaments is as follows: (13) Wherein, represents or , represents the reduction coefficient when the carbon fiber filaments / glass fiber filaments undergo tensile failure, represents the reduction coefficient when the carbon fiber filaments / glass fiber filaments undergo compressive failure, represents the tensile ultimate stress, represents the compressive ultimate stress, represents the microscopic stress of carbon fiber filaments / glass fiber filaments. After the carbon fiber filaments / glass fiber filaments undergo damage reduction, the mechanical constitutive relationship of carbon fiber filaments / glass fiber filaments at the microscopic scale changes as follows: (14) (15) Wherein, and respectively represent the microscopic stresses of carbon fiber filaments and glass fiber filaments; and respectively represent the reduction coefficients when the carbon fiber filaments and glass fiber filaments undergo tensile / compressive failure, and are respectively equal to the maximum values of the reduction coefficients of all reference points on the carbon fiber filaments and glass fiber filaments; and respectively represent the initial stiffness matrices of carbon fiber filaments and glass fiber filaments at the microscopic scale; and respectively represent the longitudinal elastic moduli of carbon fiber filaments and glass fiber filaments before damage occurs; and respectively represent the transverse elastic moduli of carbon fiber filaments and glass fiber filaments before damage occurs; and respectively represent the microscopic strains of carbon fiber filaments and glass fiber filaments at the microscopic scale; and respectively represent the longitudinal elastic moduli of carbon fiber filaments and glass fiber filaments after damage reduction at the microscopic scale; and respectively represent the transverse elastic moduli of carbon fiber filaments and glass fiber filaments after damage reduction at the microscopic scale.

[0057] Step 603, the failure of the matrix adopts the modified Von - Mises failure criterion: (16) (17) In the formula, and respectively represent the Von - Mises stress value and the critical Von - Mises stress value of the matrix; and respectively represent the first stress invariant of the matrix and the critical first stress invariant of the matrix; and respectively represent the initial tensile strength and the initial compressive strength of the matrix; , and respectively represent the microscopic stresses in six directions of the reference point on the matrix. The subscript 1 corresponds to the x - axis, 2 corresponds to the y - axis, and 3 corresponds to the z - axis. When the damage failure of the matrix starts, the value of is greater than or equal to 1. The initial tensile strength and the initial compressive strength of the matrix are obtained through experiments.

[0058] Step 604, due to the difference between the tensile strength and the compressive strength of the matrix, the present invention introduces an equivalent stress to characterize the damage evolution of the matrix, and the evolution process is as follows: (18) (19) (20) Among them, represents the equivalent stress of the matrix, represents the maximum equivalent stress value after the matrix is damaged, represents the damage factor when the matrix is in tension / compression, Represents the damage shape parameter of the matrix. After the matrix damage reduction, the mechanical constitutive relationship of the matrix at the microscale changes as follows: (21) In the formula, , and respectively represent the micro stress, initial stiffness matrix, and micro strain of the matrix at the microscale; and respectively represent the elastic modulus after matrix damage reduction and the elastic modulus when the matrix is undamaged; the matrix damage factor takes the maximum value of all reference points on the matrix.

[0059] Step 7: Establish a three-point bending finite element model of the thin-walled structure of the woven plain-layer hybrid fiber composite hat-shaped beam, and perform three-point bending test simulation analysis through the VUMAT subroutine combined with the ABAQUS / Explicit software, and compare the predicted results with the actual test results.

[0060] Step 701: Use C3D8R solid elements to model the single-hat-shaped beam thin-walled structure. The hat-shaped structure is set to 8 layers in total, and the thickness of each layer is set to 0.135 mm to obtain a three-point bending finite element model of the hat-shaped beam thin-walled structure (i.e., the macroscopic model).

[0061] Step 702: Assign material properties to the macroscopic model. The material properties are the numerical values of the elastic mechanical parameters of the macroscopic laminate predicted in Step 304 (the numerical values of the elastic mechanical parameters of the macroscopic laminate in the undamaged state of carbon fiber, glass fiber, and matrix).

[0062] Step 703: The overall mesh size of the macroscopic model is 1.5 mm × 1.5 mm. The mesh around the contact between the upper punch and the hat-shaped beam thin-walled structure in the macroscopic model is encrypted, and the mesh size around the contact is 1 mm × 1 mm, and the macroscopic stiffness matrix is initialized.

[0063] Step 704: Fix and restrict all degrees of freedom of the support base in the macroscopic model, apply a downward velocity to the upper punch and restrict other degrees of freedom, the loading velocity is set to 2 m / s, and the loading method is set to smooth loading.

[0064] Step 705: When constructing the macroscopic model, use Cohesive Behavior Contact to simulate the damage failure between layers. The damage evolution adopts the Benzeggagh-Kenane criterion based on fracture energy, and the friction coefficient between the upper punch, the support base, and the hat-shaped beam thin-walled structure is set to 0.3.

[0065] Step 706: Conduct numerical simulation by means of the VUMAT subroutine completed in Step 6, and verify the accuracy of the multi-scale theoretical model by comparing the deformation modes and failure forms of the hybrid fiber hat-shaped beam thin-walled structure.

[0066] (1) Calculate the macroscopic stresses corresponding to carbon fiber, glass fiber, and matrix respectively according to the macroscopic stiffness matrix.

[0067] (2) Calculate the microscopic stresses According to the linear equations of the matrix reduction coefficients and microscopic-macroscopic stress amplification coefficients corresponding to carbon fiber, glass fiber, and matrix respectively, and the macroscopic stresses, calculate the microscopic stresses corresponding to carbon fiber, glass fiber, and matrix respectively.

[0068] (3) Determine whether the failure criterion is satisfied. If the failure criterion is satisfied, proceed to step (4); otherwise, proceed to step (7).

[0069] Substitute the microscopic stresses of carbon fiber and glass fiber in the longitudinal direction into the formula in step 601 to determine whether carbon fiber and glass fiber satisfy the failure criterion; Substitute the microscopic stress of the matrix into the formula in step 603 to determine whether the matrix satisfies the failure criterion.

[0070] (4) Calculate the microscopic damage variable If carbon fiber and / or glass fiber satisfy the failure criterion, then according to the formula in step 602, calculate the elastic moduli along the longitudinal and as well as the transverse directions and .

[0071] If the matrix satisfies the failure criterion, then according to the formula in step 604, calculate the elastic modulus of the matrix after damage reduction at the microscopic scale .

[0072] (5) Calculate the macroscopic damage variable How to characterize the damage evolution of the macroscopic composite material after the damage evolution of the fibers and matrix at the microscopic scale is a key step in the implementation of the above multi-scale method. The macroscopic scale is affected by many parameters at the microscopic scale, such as the volume fraction of fibers, the hybrid ratio of different fibers, etc. Therefore, it is necessary to construct an expression to characterize the influence of microscopic scale parameters on the macroscopic scale. The present invention realizes the influence of the microscopic scale on the macroscopic scale by introducing a macroscopic damage variable. The setting and calculation process of the macroscopic damage variable are shown in formulas (22) and (23): (22) (23) In the formula, , and respectively represent the elastic moduli of the hybrid fiber composite material (macroscopic laminate) in the x-direction, y-direction, and z-direction at the macroscopic scale; , and respectively represent the volume fractions of carbon fiber, glass fiber, and matrix at the microscopic scale; V f is the sum of the volume fractions of carbon fiber and glass fiber; represents the sum of the elastic moduli along the transverse direction after damage reduction of carbon fiber filaments and glass fiber filaments at the microscopic scale, that is, and sum; , and respectively represent the macroscopic damage variables of the woven in-layer hybrid fiber composite material in the x-direction, y-direction, and z-direction at the macroscopic scale. The superscripts T and C represent tension and compression respectively.

[0073] (6) Update the macroscopic stiffness matrix Multiplying the calculated macroscopic damage variable by the initial stiffness matrix at the macroscopic scale can realize the real-time update of the macroscopic stiffness matrix with the continuous change of different component states at the microscopic scale. The update method of the macroscopic stiffness matrix is shown in formula (24): (24) In the formula, represents the initial stiffness matrix coefficient of the hybrid fiber composite material at the macroscopic scale, is the stiffness matrix of the hybrid fiber composite material at the macroscopic scale after damage.

[0074] (7) Iterate the incremental step (i.e., the matrix reduction coefficient) and return to step (1), and stop the iteration when the matrix reduction coefficient increases to 0.9.

[0075] The load-displacement curves and deformation modes of the experiment and the multi-scale simulation of the present invention are compared as Figure 6 shown. By comparing the load-displacement curves, it is found that the result curves of the experiment and the multi-scale simulation have good consistency. The error range between the experiment and the simulation is within 10%, and the error range is within the acceptable range, thus proving the feasibility of the present method.

[0076] In another embodiment of the present invention, a multi-scale analysis system for damage failure of hybrid fiber composite materials is provided. In this embodiment, the first fiber is carbon fiber and the second fiber is glass fiber, including: A model construction module for establishing a carbon fiber microscopic unit cell model and a glass fiber microscopic unit cell model of a hybrid fiber composite material, assigning material properties to carbon fiber filaments, glass fiber filaments and the matrix; and establishing a hybrid fiber mesoscopic unit cell model; A unit cell model simulation module for respectively applying a concentrated unit load to the carbon fiber microscopic unit cell model, the glass fiber microscopic unit cell model, and the hybrid fiber mesoscopic unit cell model, extracting stresses, and calculating the microscopic-macroscopic stress amplification factors corresponding to carbon fiber, glass fiber and the matrix respectively; reducing the material properties of the matrix to obtain the microscopic-macroscopic stress amplification factors corresponding to carbon fiber, glass fiber and the matrix respectively under different damage states of the matrix, and fitting linear equations of the matrix reduction factors and the microscopic-macroscopic stress amplification factors corresponding to carbon fiber, glass fiber and the matrix respectively; A macroscopic model construction module for establishing a macroscopic model of a hybrid fiber composite material and assigning the elastic modulus of the hybrid fiber composite material; A failure simulation module for simulating a three-point bending test on the macroscopic model, calculating the macroscopic stresses corresponding to carbon fiber, glass fiber and the matrix respectively according to the macroscopic stiffness matrix of the macroscopic model; calculating the microscopic stresses corresponding to carbon fiber, glass fiber and the matrix respectively according to the macroscopic stresses and the linear equations; judging whether carbon fiber, glass fiber and the matrix meet the failure criteria according to the microscopic stresses, if at least one component meets the failure criteria, calculating the elastic modulus after damage reduction of the component at the microscopic scale according to the microscopic stress corresponding to the component meeting the failure criteria, calculating the macroscopic damage variable according to the elastic modulus after damage reduction, updating the macroscopic stiffness matrix according to the macroscopic damage variable, and iterating the increment step, otherwise, directly iterating the increment step; the increment step is the increment of the matrix reduction factor.

[0077] In another embodiment of the present invention, a computer device is provided, which includes a processor and a memory. The memory is used to store a computer program, and the computer program includes program instructions. The processor is used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit, or may also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field programmable gate arrays or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, and is suitable for implementing one or more instructions. Specifically, it is suitable for loading and executing one or more instructions in the computer storage medium to implement the corresponding method flow or corresponding function; the processor described in the embodiment of the present invention can be used for the operation of the multi-scale analysis method for the damage failure of hybrid fiber composite materials.

[0078] In another embodiment of the present invention, the present invention further provides a storage medium, specifically a computer-readable storage medium (Memory). The computer-readable storage medium is a memory device in a computer device and is used to store programs and data. It can be understood that the computer-readable storage medium here can include both the built-in storage medium in the computer device and, of course, the extended storage medium supported by the computer device. The computer-readable storage medium provides a storage space, and the operating system of the terminal is stored in this storage space. And, one or more instructions suitable for being loaded and executed by the processor are also stored in this storage space. These instructions can be one or more computer programs (including program codes). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. One or more instructions stored in the computer-readable storage medium can be loaded and executed by the processor to implement the corresponding steps of the multi-scale analysis method for damage failure of hybrid fiber composites in the above embodiments.

[0079] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a system, or a computer program product. Therefore, the present invention can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memories, optical memories, etc.) containing computer-usable program codes.

[0080] The present invention is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present invention. It should be understood that each flow and / or block in the flowchart and / or block diagram, and the combination of flows and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0081] These computer program instructions can 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 generate a manufactured article including an instruction device, and the instruction device implements the functions in the processFigure 1 one process or multiple processes and / or blocks Figure 1 the functions specified in one block or multiple blocks

[0082] These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process. Thus, the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one process Figure 1 one process or multiple processes and / or blocks Figure 1 the steps of the functions specified in one block or multiple blocks

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that it is still possible to modify the specific implementation manners of the present invention or make equivalent substitutions. Any modification or equivalent substitution that does not depart from the spirit and scope of the present invention shall be covered by the protection scope of the present invention.

[0084] Although the present invention has been described above with reference to the embodiments, various improvements can be made to it and components therein can be replaced with equivalents without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the various features in the disclosed embodiments of the present invention can be combined with each other in any way. The exhaustive description of these combinations is omitted in this specification only for the sake of saving space and resources. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A multi-scale analysis method for damage and failure of hybrid fiber composites, characterized in that Including: S1. Establish a first fiber microscopic unit cell model and a second fiber microscopic unit cell model of the hybrid fiber composite material, and assign the material properties of the first fiber filament, the second fiber filament and the matrix; establish a hybrid fiber mesoscopic unit cell model; S2. Apply a concentrated unit load to the first fiber microscopic unit cell model, the second fiber microscopic unit cell model and the hybrid fiber mesoscopic unit cell model respectively, extract the stress, and calculate the microscopic-macroscopic stress amplification factors corresponding to the first fiber, the second fiber and the matrix respectively; S3. Reduce the material properties of the matrix, repeat S2, and then fit the linear equations of the matrix reduction coefficients and the microscopic-macroscopic stress amplification factors corresponding to the first fiber, the second fiber and the matrix respectively; S4. Establish a macroscopic model of the hybrid fiber composite material, assign the elastic modulus of the hybrid fiber composite material, conduct a three-point bending test simulation, and calculate the macroscopic stresses corresponding to the first fiber, the second fiber and the matrix respectively according to the macroscopic stiffness matrix of the macroscopic model; S5. Calculate the microscopic stresses corresponding to the first fiber, the second fiber and the matrix respectively according to the macroscopic stresses obtained in S4 and the linear equations obtained in S3; Judge whether the first fiber, the second fiber and the matrix meet the failure criterion according to the microscopic stress. If at least one component meets the failure criterion, calculate the elastic modulus after damage reduction of the component at the microscopic scale according to the microscopic stress corresponding to the component that meets the failure criterion. Otherwise, go to S7; S6. Calculate the macroscopic damage variable according to the elastic modulus after damage reduction, and update the macroscopic stiffness matrix according to the macroscopic damage variable; S7. Iterate the increment step and return to S4, where the increment step is the increment of the matrix reduction coefficient.

2. The multi-scale analysis method for damage failure of the hybrid fiber composite material according to claim 1, wherein S1 includes: S11. Obtain the volume fractions of the first fiber filaments and the second fiber filaments at the microscopic scale and the volume fractions of the first fiber bundles and the second fiber bundles at the mesoscopic scale in the hybrid fiber composite material, and establish a first fiber microscopic unit cell model, a second fiber microscopic unit cell model and a hybrid fiber mesoscopic unit cell model without pores respectively according to the obtained volume fractions; S12. Randomly select a preset proportion of matrix grid cells in all matrix grid cells of the first fiber microscopic unit cell model, the second fiber microscopic unit cell model and the hybrid fiber mesoscopic unit cell model without pores, and simulate pores with the selected matrix grid cells to obtain a first fiber microscopic unit cell model, a second fiber microscopic unit cell model and a hybrid fiber mesoscopic unit cell model containing pores; assign the material properties of the first fiber, the second fiber and the matrix to the first fiber microscopic unit cell model and the second fiber microscopic unit cell model.

3. The multi-scale analysis method for damage failure of the hybrid fiber composite material according to claim 1, characterized in that S2 specifically includes: S21. Apply periodic boundary conditions to the first fiber microscopic unit cell model and the second fiber microscopic unit cell model respectively, apply concentrated unit loads under six different working conditions, calculate the elastic mechanical parameters of the first fiber bundle and the second fiber bundle respectively, assign the elastic mechanical parameters of the first fiber bundle and the second fiber bundle to the hybrid fiber mesoscopic unit cell model, apply periodic boundary conditions, apply concentrated loads under six different working conditions, and calculate the elastic modulus of the hybrid fiber composite material; S22. When applying a concentrated unit load, extract the stresses of the first fiber grid elements, the second fiber grid elements, and the matrix grid elements in the first fiber microscopic unit cell model, the second fiber microscopic unit cell model, and the hybrid fiber mesoscopic unit cell model under different working conditions. Based on the obtained stresses, select reference points through cluster analysis. By calculating the stress amplification factors of the reference points, obtain the microscopic-mesoscopic stress amplification factors corresponding to the first fiber, the second fiber, and the matrix respectively, as well as the mesoscopic-macroscopic stress amplification factors corresponding to the first fiber, the second fiber, and the matrix respectively. Multiply the microscopic-mesoscopic stress amplification factors by the corresponding mesoscopic-macroscopic stress amplification factors to obtain the microscopic-macroscopic stress amplification factors corresponding to the first fiber, the second fiber, and the matrix respectively.

4. The multi-scale analysis method for damage failure of hybrid fiber composites according to claim 3, characterized in that S22 specifically includes: S221. After applying concentrated loads with six different working conditions to the first fiber microscopic unit cell model, extract the stresses of the first fiber grid elements and the matrix grid elements in the first fiber microscopic unit cell model in six directions respectively. Each grid element obtains a 6×6 stress amplification factor matrix. S222, convert the stress amplification factor matrix into a 1×36 matrix ; S223. Arrange the matrices of all the first fiber grid cells and all the matrix grid cells in the first fiber microcell model respectively into a matrix B . The number of rows of the matrix B is equal to the total number of grid cells in the corresponding component; S224. Conduct cluster analysis on the matrices B corresponding to the first fiber and the matrix respectively, use the obtained cluster centers as reference points, and obtain the microscopic-mesoscopic stress amplification factors corresponding to the first fiber and the matrix in the first fiber microscopic unit cell model based on the reference points. S225. According to the methods of S221 - S224, obtain the microscopic-mesoscopic stress amplification factors corresponding to the second fiber and the matrix in the second fiber microscopic unit cell model respectively, and the mesoscopic-macroscopic stress amplification factors corresponding to the first fiber, the second fiber, and the matrix in the hybrid fiber mesoscopic unit cell model respectively. Combine the microscopic-mesoscopic stress amplification factors corresponding to the matrix in the first fiber microscopic unit cell model and the microscopic-mesoscopic stress amplification factors corresponding to the matrix in the second fiber microscopic unit cell model to obtain the microscopic-mesoscopic stress amplification factor corresponding to the matrix. S226. Multiply the microscopic-mesoscopic stress amplification factor corresponding to the first fiber by the mesoscopic-macroscopic stress amplification factor corresponding to the first fiber, multiply the microscopic-mesoscopic stress amplification factor corresponding to the second fiber by the mesoscopic-macroscopic stress amplification factor corresponding to the second fiber, and multiply the microscopic-mesoscopic stress amplification factor corresponding to the matrix by the mesoscopic-macroscopic stress amplification factor corresponding to the matrix to obtain the microscopic-macroscopic stress amplification factors corresponding to the first fiber, the second fiber, and the matrix respectively.

5. The multi-scale analysis method for damage failure of hybrid fiber composites according to claim 1, characterized in that, S3 specifically includes: S31. Set the reduction coefficients of the first fiber and the second fiber in the first fiber microscopic unit cell model, the second fiber microscopic unit cell model, and the mesoscopic unit cell model to 0, and set the reduction coefficients of the matrix to 0, 0.1, 0.3, 0.6, and 0.9 respectively. Reduce the material properties of the matrix, repeat S2, and calculate the microscopic-macroscopic stress amplification factors corresponding to the first fiber, the second fiber, and the matrix under different damage states of the matrix. S32. Taking the reduction coefficient of the matrix as the independent variable and the microscopic-macroscopic stress amplification coefficients corresponding to the first fiber, the second fiber, and the matrix respectively as the dependent variables, fitting a linear equation to obtain the linear equations of the matrix reduction coefficients and the microscopic-macroscopic stress amplification coefficients corresponding to the first fiber, the second fiber, and the matrix respectively when the first fiber and the second fiber are undamaged. S33. Setting the reduction coefficients of the first fiber and the second fiber to 0.9, repeating S31 and S32, calculating the microscopic-macroscopic stress amplification coefficients corresponding to the first fiber, the second fiber, and the matrix respectively under different damage states of the matrix and fitting a linear equation to obtain the linear equations of the matrix reduction coefficients and the microscopic-macroscopic stress amplification coefficients corresponding to the first fiber, the second fiber, and the matrix respectively when the first fiber and the second fiber are damaged.

6. The multi-scale analysis method for damage failure of hybrid fiber composites according to claim 1, characterized in that, In S5, the failure criteria for the first fiber and the second fiber are: In the formula, represents the microscopic stress of the first fiber filament / second fiber filament in the longitudinal direction at the microscopic scale, represents the initial tensile strength of the first fiber filament / second fiber filament, represents the initial compressive strength of the first fiber filament / second fiber filament; If the calculated and values are greater than or equal to 1, the first fiber filament / second fiber filament is damaged and fails; The failure criterion for the matrix is: In the formula, and respectively represent the Von-Mises stress value and the critical Von-Mises stress value of the matrix; and respectively represent the first stress invariant of the matrix and the critical first stress invariant of the matrix; and respectively represent the initial tensile strength and the initial compressive strength of the matrix; , and respectively represent the microscopic stresses in six directions of the reference point on the matrix, where the subscript 1 corresponds to the x-axis, 2 corresponds to the y-axis, and 3 corresponds to the z-axis. When the value of is greater than or equal to 1, damage failure of the matrix occurs.

7. The multi-scale analysis method for damage failure of hybrid fiber composites according to claim 1, characterized in that, S6 specifically includes: Calculation of macroscopic damage variables: In the formula, , and respectively represent the elastic moduli of the hybrid fiber composite material in the x-direction, y-direction, and z-direction at the macroscopic scale; , and respectively represent the volume fractions of the first fiber, the second fiber, and the matrix at the microscopic scale; V f is the sum of the volume fractions of the first fiber and the second fiber; , and respectively represent the macroscopic damage variables of the hybrid fiber composite material in the x-direction, y-direction, and z-direction at the macroscopic scale. The superscripts T and C represent tension and compression respectively; and are respectively the elastic moduli along the longitudinal direction after damage reduction of the first fiber filament and the second fiber filament at the microscopic scale; is and the sum of, and are respectively the elastic moduli along the transverse direction after damage reduction of the first fiber filament and the second fiber filament at the microscopic scale; represents the elastic modulus after damage reduction of the matrix at the microscopic scale; Updating the macroscopic stiffness matrix: Multiplying the calculated macroscopic damage variables by the initial stiffness matrix at the macroscopic scale to obtain the macroscopic stiffness matrix.

8. A multi-scale analysis system for damage and failure of hybrid fiber composites, characterized in that, Including: A model construction module for establishing the first fiber microscopic unit cell model and the second fiber microscopic unit cell model of the hybrid fiber composite material and assigning the material properties of the first fiber filament, the second fiber filament, and the matrix; establishing the hybrid fiber mesoscopic unit cell model. A unit cell model simulation module for applying a concentrated unit load to the first fiber microscopic unit cell model, the second fiber microscopic unit cell model, and the hybrid fiber mesoscopic unit cell model respectively, extracting the stress, and calculating the microscopic-macroscopic stress amplification coefficients corresponding to the first fiber, the second fiber, and the matrix respectively; reducing the material properties of the matrix to obtain the microscopic-macroscopic stress amplification coefficients corresponding to the first fiber, the second fiber, and the matrix respectively under different damage states of the matrix, and fitting to obtain the linear equations of the matrix reduction coefficients and the microscopic-macroscopic stress amplification coefficients corresponding to the first fiber, the second fiber, and the matrix respectively. A macroscopic model construction module for establishing the macroscopic model of the hybrid fiber composite material and assigning the elastic modulus of the hybrid fiber composite material. A failure simulation module for simulating a three-point bending test on the macroscopic model, calculating the macroscopic stresses corresponding to the first fiber, the second fiber, and the matrix respectively according to the macroscopic stiffness matrix of the macroscopic model; calculating the microscopic stresses corresponding to the first fiber, the second fiber, and the matrix respectively according to the macroscopic stresses and the linear equations. Judging whether the first fiber, the second fiber, and the matrix meet the failure criteria according to the microscopic stresses. If at least one component meets the failure criteria, calculating the elastic modulus of the component after damage reduction at the microscopic scale according to the microscopic stress corresponding to the component that meets the failure criteria, calculating the macroscopic damage variable according to the elastic modulus after damage reduction, updating the macroscopic stiffness matrix according to the macroscopic damage variable, and iterating the increment step. Otherwise, directly iterating the increment step; the increment step is the increment of the matrix reduction coefficient.

9. A computer device, characterized in that, Comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, when the processor executes the computer program, it implements the multi-scale analysis method for damage failure of hybrid fiber composite materials according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, it implements the multi-scale analysis method for damage failure of hybrid fiber composite materials according to any one of claims 1 to 7.

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