Three-dimensional braided composite material coupling design method and system based on cross-scale analysis

Abstract

The invention provides a three-dimensional braided composite coupling design method and system based on cross-scale analysis, and belongs to the technical field of electric digital data processing. According to the method, representative volume element models with specific weaving angles and fiber volume fractions are established according to different spatial positions of the coupler; the macroscopic equivalent elastic modulus and strength of each position are obtained through finite element analysis and a volume averaging method; establishing a coupler macroscopic finite element model, endowing the model with equivalent performance parameters, and analyzing a failure index and an inherent frequency of the model under a design load; and by taking mass minimization as a target and the failure index and the inherent frequency as constraints, constructing an optimization model, and iteratively adjusting a weaving angle, a volume fraction and a structural size through a heuristic algorithm, thereby realizing light weight and performance collaborative optimization of the coupler. According to the method, the design problem caused by multiple parameter freedom degrees and high multi-scale coupling performance of the three-dimensional braided coupling is solved, and an optimal design scheme meeting the requirements of complex working conditions can be efficiently and automatically obtained.

Description

Technical Field

[0001] This invention belongs to the field of electronic digital data processing technology, and relates to the finite element method in computer-aided design, design optimization, verification or simulation, and composite materials. Specifically, it relates to a design method and system for three-dimensional braided composite material couplings based on cross-scale analysis. Background Technology

[0002] Couplings, as a key basic component in mechanical transmission systems, are mainly used to connect two shafts, enabling them to rotate together to transmit torque and motion. Traditional couplings are mostly made of metal materials, such as 45 steel, aluminum alloy, and stainless steel. Although metal couplings are widely used, with the increasing demands for lightweighting in modern high-end equipment and the ever-improving operating environments, the relatively low stiffness-to-strength ratio, strength-to-weight ratio, and corrosion resistance of metal materials limit their application range. To overcome these shortcomings, composite material couplings have emerged.

[0003] Composite materials, with their superior properties such as high specific strength, high specific modulus, strong designability, fatigue resistance, and corrosion resistance, offer new avenues for improving coupling performance. Existing technologies already include couplings manufactured using composite materials. For example, Liu Changxi designed a composite high-compensation flexible diaphragm coupling in Chinese patent application CN108087442A and provided a corresponding design method in Chinese patent application CN108595724A. However, these composite material couplings are mainly manufactured based on ply layup, and their design process primarily revolves around the macroscopic dimensions of the components and the ply sequence. While ply layup composite material couplings achieve weight reduction to some extent, they inherently suffer from weak interlaminar properties. Under impact or complex alternating loads, they are prone to delamination, leading to progressive structural failure during continuous torque transmission and limiting reliability.

[0004] In recent years, three-dimensional braided composite materials, by interlacing in the X, Y, and Z directions to form an integral fiber network structure, have significantly improved the performance of composite materials in the thickness direction, achieving a level comparable to in-plane performance. This holds promise for fundamentally solving problems such as weak interlaminar structure and poor impact resistance in traditional plywood composites. However, the realization of the structural performance advantages of three-dimensional braided composite materials is highly dependent on microscopic design parameters such as braiding angle and fiber volume fraction. Compared with plywood composites, three-dimensional braiding offers greater design freedom and more complex spatial distribution of parameters, leading to greater challenges in cross-scale design and performance optimization of complex components such as couplings. How to effectively correlate and synergistically optimize microscopic braiding parameters with macroscopic component performance has become a key challenge in the design of three-dimensional braided composite couplings.

[0005] Currently, there are some relevant studies on the multi-scale design and optimization of composite material structures:

[0006] (1) Chinese patent application CN115238555A discloses a multi-scale analysis method for three-dimensional braided composite thin-walled structures based on local homogenization. This method improves computational efficiency by establishing a mesoscopic unit cell model and performing local homogenization. However, this method mainly focuses on predicting the mechanical properties of thin-walled structures and does not involve how to couple and optimize mesoscopic design parameters (such as braiding angle and volume fraction) with the multi-objective properties of macroscopic components (such as torque transmission capacity, vibration characteristics, and lightweighting). It also does not consider the dynamic load and reliability constraints unique to couplings in the optimization framework. Therefore, it is difficult to directly use it to guide the systematic design of three-dimensional braided composite couplings.

[0007] (2) The paper "Zhang H, Li S, Wu Y, et al. A Multiscale Reliability-Based Design Optimization Method for Carbon-Fiber-Reinforced Composite Drive Shafts" presents a design method for carbon fiber-reinforced composite drive shafts based on multiscale reliability optimization. This method introduces optimization strategies such as particle swarm optimization to automatically optimize the ply composite material, achieving progress in balancing lightweighting and reliability. However, the functions and core stress states of drive shafts and couplings in the transmission system are fundamentally different. Drive shafts mainly bear pure torsional loads and dynamic balance problems under high-speed rotation, and their design focuses on torsional stiffness, critical speed, and axial strength. The core function of couplings is to connect two shafts and compensate for radial, axial, and angular misalignments during installation. Their working conditions are more complex. In addition to transmitting torque, they also need to withstand compound loads such as additional bending moments and radial forces caused by misalignment. Therefore, the design of couplings must simultaneously balance multiple coupled objectives such as torsional performance, multi-directional compensation capability, fatigue life, and suppression of specific vibration modes. Directly applying optimization models and failure criteria established for drive shafts with pure torsion as the core constraint to the design of 3D braided composite couplings makes it difficult to comprehensively evaluate their overall performance and failure risk under real and complex working conditions. Furthermore, the optimization framework of this method mainly revolves around plywood composites, while 3D braided composites have more complex spatial interweaving characteristics and more diverse micro-design variables (strong coupling effects of multiple parameters such as braiding angle, fiber volume fraction, and spatial gradient distribution). The significant differences in their design paradigms lead to insufficient model adaptability and difficulty in effectively coordinating the strong coupling relationships of multiple parameters when applying optimization strategies based on plywood assumptions to 3D braided couplings.

[0008] In summary, the existing technology has the following shortcomings:

[0009] (1) There is a lack of gradient design methods that dynamically correlate the micro-weaving parameters of three-dimensional braided composite materials with the macro-component performance of couplings.

[0010] (2) The special performance constraints of the coupling in terms of torque transmission and vibration suppression were not fully considered.

[0011] (3) There is a lack of a design framework that can systematically and collaboratively optimize micro-weaving parameters and macro-structural dimensions while ensuring structural reliability, thereby achieving lightweighting and optimal overall performance. Existing optimization methods derived from other components (such as drive shafts) or composite material forms (such as layups) face challenges in terms of model accuracy, solution efficiency, and global optimization capability when dealing with the multi-scale, multi-objective, and strongly constrained collaborative design problem of three-dimensional braided composite material couplings. Summary of the Invention

[0012] This invention is made to solve the above-mentioned problems, and aims to provide a design method and system for three-dimensional braided composite material couplings based on cross-scale analysis.

[0013] This invention provides a design method for three-dimensional braided composite material couplings based on cross-scale analysis. The method features a three-dimensional braided composite material for manufacturing the coupling, comprising a resin matrix and fiber bundles of carbon fiber as the braiding material. The method includes the following steps: S10, considering different spatial positions of the coupling... The braiding angle of the fiber bundles in the initial microstructure model of the three-dimensional braided composite material at this location. and volume fraction This establishes several different representative volume element models; S20, after importing the representative volume element models into the finite element preprocessing software, test loads are applied to obtain the stress and strain of each unit cell of the representative volume element models; S30, based on the stress and strain of the unit cells, the spatial position of the coupling is obtained using the volume averaging method. The macroscopic equivalent elastic modulus of the three-dimensional braided composite material was used to predict the spatial location of the coupling based on the Hashin progressive damage failure model. The equivalent macroscopic strength of the three-dimensional braided composite material at point S40; Establish the macroscopic finite element model of the coupling, and define the macroscopic finite element model of the coupling at point S40. dimensional parameters of a three-dimensional woven composite material at a spatial location Subsequently, the macroscopic equivalent elastic modulus and equivalent macroscopic strength are assigned to the macroscopic finite element model, and finally, finite element analysis of the macroscopic finite element model under the design load of the coupling is performed; S50, adjust , , After repeating steps S10 to S40, substitute several results from the finite element analysis into the optimization model. Solving for the problem completes the design of the coupling, where, Indicates the preset spatial location The total number, This represents the design variables of the coupling obtained from the solution. Indicated by , , The total mass of the coupling is a function of the design variables. The optimization model represents the total mass of the coupling. Minimize as the target design requirement. This indicates the constraint requirements that the design variables obtained from the solution must satisfy. Indicated by , , The failure index of the coupling structure is a design variable. Indicated by , , The natural frequency of the coupling structure is a design variable. This represents the failure index threshold. Indicates frequency requirement, , , These represent the minimum values ​​of the weave angle, volume fraction, and dimensional parameters, respectively. , , These represent the maximum values ​​of the weave angle, volume fraction, and dimensional parameters, respectively.

[0014] The design method for three-dimensional braided composite material couplings based on cross-scale analysis provided by the present invention may also have the following feature: wherein, in step S20, the finite element preprocessing software includes ABAQUS CAE or Hypermesh.

[0015] The design method for three-dimensional braided composite material couplings based on cross-scale analysis provided by the present invention may also have the following features: in step S20, the finite element preprocessing software performs finite element mesh generation on the representative volume element model and applies periodic boundary conditions to it.

[0016] The design method for three-dimensional braided composite material couplings based on cross-scale analysis provided by the present invention may also have the following feature: in step S20, the periodic boundary conditions are achieved by constraining the displacement phase of the corresponding nodes of the representative unit cell.

[0017] The design method for three-dimensional braided composite material couplings based on cross-scale analysis provided by the present invention may also have the following feature: in step S20, the test load includes tensile, compressive and shear loads.

[0018] The design method for three-dimensional braided composite material couplings based on cross-scale analysis provided by this invention may also have the following features: wherein, in step S40, performing finite element analysis of the macroscopic finite element model under the design load of the coupling includes: applying a torsional load to the macroscopic finite element model to perform stress intensity analysis to obtain the failure index of the structure of the coupling under the design load; and performing modal analysis on the macroscopic finite element model to obtain the natural frequencies of each order of the coupling.

[0019] The three-dimensional braided composite material coupling design method based on cross-scale analysis provided by this invention may also have the following feature: wherein, in steps S10 to S50, the braiding angle... The corresponding fiber bundle weaving methods include three-dimensional four-way weaving and three-dimensional five-way weaving.

[0020] The three-dimensional braided composite material coupling design method based on cross-scale analysis provided by this invention may also have the following feature: wherein, in step S50, a heuristic algorithm is used to execute... , , Solving the adjustment and optimization model.

[0021] The design method for three-dimensional braided composite material couplings based on cross-scale analysis provided by the present invention may also have the following features: in step S50, the heuristic algorithm includes a genetic algorithm and a particle swarm algorithm.

[0022] This invention also provides a three-dimensional braided composite material coupling design system based on cross-scale analysis, characterized by using any of the aforementioned three-dimensional braided composite material coupling design methods based on cross-scale analysis, including: a modeling module for different spatial positions of the coupling. The braiding angle of the fiber bundles in the initial microstructure model of the three-dimensional braided composite material at that location is specified by the user. and volume fraction This allows for the establishment of several different representative volume element models. The finite element preprocessing module imports these models into the software, processes them, and applies test loads to obtain the stress and strain of each unit cell. The macroscopic performance calculation module, based on the stress and strain of these unit cells, calculates the spatial position of the coupling using the volume averaging method. The macroscopic equivalent elastic modulus of the three-dimensional braided composite material was used to predict the spatial location of the coupling based on the Hashin progressive damage failure model. The equivalent macroscopic strength of the three-dimensional braided composite material at the location; the coupling macroscopic analysis module, used to establish the macroscopic finite element model of the coupling, and then for users to define the macroscopic finite element model of the coupling in the first position. dimensional parameters of a three-dimensional woven composite material at a spatial location Subsequently, the macroscopic equivalent elastic modulus and equivalent macroscopic strength are assigned to the macroscopic finite element model. Finally, finite element analysis of the macroscopic finite element model under the design load of the coupling is performed. A design evaluation and iteration module is used to adjust... , , After repeatedly executing the functions of the modeling module, finite element preprocessing module, macroscopic performance calculation module, and coupling macroscopic analysis module, the results of the finite element analysis are substituted into the optimization model to solve, thereby completing the design of the coupling.

[0023] The present invention has the following beneficial effects:

[0024] (1) This invention introduces a three-dimensional braided composite material design for composite couplings, which greatly improves the interlayer performance of the couplings and can effectively resist delamination failure of composite materials. Furthermore, it provides a systematic design framework for three-dimensional braided composite couplings, combining and optimizing the unique microscopic design variables (braiding angle, fiber volume fraction) of three-dimensional braided composite materials with the macroscopic structural dimensions of the coupling. This effectively solves the problems faced by three-dimensional braided composite materials in coupling design due to their extremely high degree of parameter freedom, filling the gap in systematic design methods in this field. Compared with traditional single-layer design, it expands the design space of couplings by leveraging its dimensional synergy advantages.

[0025] (2) This invention establishes multiple representative volumetric element models for different spatial locations of the coupling and obtains their equivalent macroscopic performance based on finite element analysis and the volume averaging method. This allows for a more accurate reflection of the influence of the gradient changes in the three-dimensional braided composite material structure on the overall performance. Combined with the Hashin progressive damage failure model, it enables quantitative prediction of the failure risk at critical locations of the coupling, providing a reliable performance evaluation basis for optimized design, and ultimately achieving high-precision cross-scale performance prediction.

[0026] (3) This invention takes minimizing the total mass of the coupling as its core objective, and uses the failure index and natural frequency of the structure as key constraints to establish a dedicated optimization model that fits the working conditions of the coupling. This makes the optimization results highly consistent with the actual engineering requirements, overcoming the limitations of directly applying the optimization model of simple torsional components such as drive shafts.

[0027] (4) This invention automatically substitutes the finite element analysis results into the parameterized optimization model and uses a heuristic algorithm to automatically iteratively adjust the micro-weaving parameters and macro-dimensions, thereby realizing the automated optimization of the design process. It can efficiently explore complex multivariate design spaces and quickly converge to the lightweight optimal solution under the premise of ensuring performance constraints. This greatly reduces the time and manpower costs required by the traditional trial and error method and significantly improves the design efficiency and automation level of three-dimensional braided composite material couplings.

[0028] (5) In the optimization process, this invention sets reasonable upper and lower limits for the weaving angle, volume fraction, and dimensional parameters, and considers specific weaving methods such as three-dimensional four-dimensional and five-dimensional weaving, ensuring that the final optimized design scheme is feasible under existing three-dimensional weaving process conditions. Based on the optimization results constrained by the failure index and natural frequency, the structural safety and dynamic stability of the coupling during use are guaranteed from the design source.

[0029] (6) This invention can maximize the weight reduction of the structure while meeting all the hard constraints of the mechanical properties (strength, stiffness) and dynamic characteristics (natural frequency) of the coupling. Compared with traditional metal couplings or composite material design schemes that rely on experience, this invention can find the maximum performance of three-dimensional braided composite material couplings, achieve the dual goals of weight reduction and performance improvement, and achieve significant weight reduction effect and comprehensive performance improvement. Attached Figure Description

[0030] Figure 1 This is a flowchart of a three-dimensional braided composite material coupling design method based on cross-scale analysis, according to an embodiment of the present invention.

[0031] Figure 2 This is an architectural diagram of a three-dimensional braided composite material coupling design system based on cross-scale analysis, according to an embodiment of the present invention.

[0032] Figure 3 This is the geometric model of the fiber bundle in the representative volumetric unit model of the test example of the present invention.

[0033] Figure 4 This is a mesh model of a representative volume element model processed by the finite element preprocessing software in the test example of the present invention, wherein (a) is a mesh model of fiber bundles and (b) is a mesh model of resin matrix.

[0034] Figure 5 These are stress cloud diagrams and damage cloud diagrams of unit cells in the test examples of this invention.

[0035] Figure 6 This is the macroscopic finite element model in the test example of this invention.

[0036] Figure 7The failure measurement cloud map is obtained from the finite element analysis (stress intensity analysis) of the macroscopic finite element model in the test example of the present invention under the design load of the coupling.

[0037] Figure 8 This is a schematic diagram showing the results of finite element analysis (modal analysis) of the macroscopic finite element model in the test example of this invention under the design load of the coupling.

[0038] Figure 9 This is the geometric model of the fiber bundle in the newly established representative volumetric unit model during the verification process of the test examples of this invention.

[0039] Figure 10 This is a mesh model of a representative volume element model after processing by finite element preprocessing software during the verification process of the test example of the present invention, wherein (a) is a mesh model of fiber bundles and (b) is a mesh model of resin matrix.

[0040] Figure 11 These are stress cloud diagrams and damage cloud diagrams of a newly established representative volumetric element model during the verification process of the test examples of this invention.

[0041] Figure 12 The failure measurement cloud map is obtained by finite element analysis (stress intensity analysis) of the new macroscopic finite element model under the design load of the coupling during the verification process of the test example of the present invention.

[0042] Figure 13 This is a schematic diagram showing the results of finite element analysis (modal analysis) of the new macroscopic finite element model under the design load of the coupling during the verification process of the test example of the present invention. Detailed Implementation

[0043] To make the technical means, creative features, objectives and effects of this invention easy to understand, the following embodiments, in conjunction with the accompanying drawings, specifically illustrate a design method and system for a three-dimensional braided composite material coupling based on cross-scale analysis.

[0044] Example

[0045] This embodiment provides a design method for three-dimensional braided composite material couplings based on cross-scale analysis. The three-dimensional braided composite material used to manufacture the coupling includes a resin matrix and fiber bundles of carbon fiber as the braiding material.

[0046] Figure 1 This is a flowchart of a three-dimensional braided composite material coupling design method based on cross-scale analysis, according to an embodiment of the present invention.

[0047] like Figure 1As shown, the design method for three-dimensional braided composite material couplings based on cross-scale analysis in this embodiment includes the following steps:

[0048] S10, Modeling a representative volumetric element model:

[0049] For different spatial positions of the coupling The braiding angle of the fiber bundles in the initial microstructure model of the three-dimensional braided composite material at this location. and volume fraction This allows for the establishment of several different representative volumetric unit models.

[0050] Among them, the weaving corner The corresponding fiber bundle weaving methods include three-dimensional four-way weaving and three-dimensional five-way weaving.

[0051] S20, Finite element preprocessing of representative volumetric element models:

[0052] After importing the representative volume element model into the finite element preprocessing software ABAQUS CAE for finite element mesh generation and applying periodic boundary conditions by constraining the displacement phase of the corresponding nodes of the representative unit cell, test loads (tensile, compressive, and shear loads) are applied to obtain the stress and strain of each unit cell of several representative volume element models.

[0053] S30, calculate the macroscopic performance of the coupling at various spatial positions:

[0054] The spatial position of the coupling is obtained based on the stress and strain of several unit cells using the volume averaging method. Macroscopic equivalent elastic modulus of three-dimensional braided composite material; prediction of spatial location of coupling based on Hashin progressive damage failure model. The equivalent macroscopic strength of the three-dimensional braided composite material at the location.

[0055] S40, performing multi-scale finite element modeling and analysis of couplings:

[0056] Establish a macroscopic finite element model of the coupling, and define the macroscopic finite element model of the coupling in the first... dimensional parameters of a three-dimensional woven composite material at a spatial location Subsequently, the macroscopic equivalent elastic modulus and equivalent macroscopic strength calculated in step S30 are assigned to the macroscopic finite element model. Finally, finite element analysis of the macroscopic finite element model under the design load of the coupling is performed, including applying torsional load to the macroscopic finite element model to perform stress intensity analysis to obtain the failure index of the coupling structure under the design load, and performing modal analysis on the macroscopic finite element model to obtain the natural frequencies of the coupling at each order.

[0057] S50, Design Evaluation and Iteration:

[0058] Adjustment is performed using a heuristic algorithm (specifically, a genetic algorithm is used in this embodiment). , , After repeating steps S10 to S40, substitute several results from the finite element analysis obtained in step S40 into the optimization model. The solution is then used to complete the design of the coupling.

[0059] In the above optimization model, Indicates the preset spatial location The total number, This represents the design variables of the coupling obtained from the solution. Indicated by , , The total mass of the coupling is a function of the design variables. The optimization model represents the total mass of the coupling. Minimize as the target design requirement. This indicates the constraint requirements that the design variables obtained from the solution must satisfy. Indicated by , , The failure index of the coupling structure is a design variable. Indicated by , , The natural frequency of the coupling structure is a design variable. This represents the failure index threshold. Indicates frequency requirement, , , These represent the minimum values ​​of the weave angle, volume fraction, and dimensional parameters, respectively. , , These represent the maximum values ​​of the weave angle, volume fraction, and dimensional parameters, respectively.

[0060] Figure 2 This is an architectural diagram of a three-dimensional braided composite material coupling design system based on cross-scale analysis, according to an embodiment of the present invention.

[0061] like Figure 2 As shown, this embodiment also provides a three-dimensional braided composite material coupling design system 100 based on cross-scale analysis, which uses the three-dimensional braided composite material coupling design method based on cross-scale analysis in this embodiment, including a modeling module 10, a finite element preprocessing module 20, a macroscopic performance calculation module 30, a coupling macroscopic analysis module 40, and a design evaluation and iteration module 50.

[0062] Modeling module 10 is used to model the coupling in different spatial positions according to step S10. The braiding angle of the fiber bundles in the initial microstructure model of the three-dimensional braided composite material at that location is specified by the user. and volume fraction This allows for the establishment of several different representative volumetric unit models.

[0063] The finite element preprocessing module 20 is used to import representative volume element models into the finite element preprocessing software for processing in accordance with step S20, and then apply test loads to obtain the stress and strain of each unit cell of several representative volume element models.

[0064] The macroscopic performance calculation module 30 is used to obtain the spatial position of the coupling based on the stress and strain of several unit cells using the volume averaging method, in accordance with step S30. The macroscopic equivalent elastic modulus of the three-dimensional braided composite material was used to predict the spatial location of the coupling based on the Hashin progressive damage failure model. The equivalent macroscopic strength of the three-dimensional braided composite material at the location.

[0065] The coupling macroscopic analysis module 40 is used to establish a macroscopic finite element model of the coupling according to step S40, and then allow the user to define the macroscopic finite element model of the coupling in the first step. dimensional parameters of a three-dimensional woven composite material at a spatial location Subsequently, the macroscopic equivalent elastic modulus and equivalent macroscopic strength are assigned to the macroscopic finite element model, and finally, the macroscopic finite element model is subjected to finite element analysis under the design load of the coupling.

[0066] The design evaluation and iteration module 50 is used to adjust according to step S50. , , After repeatedly executing the functions of modeling module 10, finite element preprocessing module 20, macroscopic performance calculation module 30, and coupling macroscopic analysis module 40, the results of the finite element analysis are substituted into the optimization model to solve, thereby completing the design of the coupling.

[0067] Test case

[0068] This test case uses the three-dimensional braided composite material coupling design system 100 based on cross-scale analysis in the embodiment to design a coupling by conducting actual tests according to the three-dimensional braided composite material coupling design method based on cross-scale analysis in the embodiment.

[0069] Before starting the test, the performance requirements of the coupling must first be set:

[0070] (1) In 500 It does not break under certain torque.

[0071] (2) The frequency corresponding to the first bending mode is greater than 150Hz.

[0072] (3) The frequency corresponding to the first-order axial tensile mode is greater than 150Hz.

[0073] (4) The frequency corresponding to the first torsional mode is greater than 1000Hz.

[0074] (5) The frequency corresponding to the first-order shear mode is greater than 200Hz.

[0075] In order to design the above coupling:

[0076] In step S10: the fiber bundles in the initial microstructure model are specified to be 3D four-way braided, and different spatial positions are... Woven corner The initial value is uniformly set to 60°, and the volume fraction is... The initial value is uniformly set to 50%. The resulting representative volumetric unit model includes a resin matrix and fiber bundles made of carbon fiber material as the weaving material. The geometric model of the fiber bundles is as follows: Figure 3 As shown.

[0077] In step S20:

[0078] (1) The mesh model of the fiber bundle and resin matrix after processing by the finite element preprocessing software is as follows: Figure 4 As shown.

[0079] (2) The stress contour plots and damage contour plots of the unit cells obtained by applying test loads to the unit cells of the representative volume element model are as follows: Figure 5 As shown.

[0080] In step S30:

[0081] The calculated macroscopic equivalent elastic modulus and equivalent macroscopic strength are shown in Table 1 below.

[0082] Table 1 (Macroscopic equivalent elastic modulus and equivalent macroscopic strength)

[0083]

[0084] In Table 1 above, This represents the elastic modulus in the 1st direction. This represents the elastic modulus in two directions. Indicates the principal Poisson ratio, Indicates the second Poisson ratio, Indicates the in-plane shear modulus. Represents out-of-plane shear modulus. This represents the tensile strength in direction 1. Represents the compressive strength in direction 1. Indicates tensile strength in two directions. Indicates compressive strength in two directions. Indicates in-plane shear strength. It represents out-of-plane shear strength.

[0085] In step S40:

[0086] (1) Define the macroscopic finite element model of the coupling in the first... dimensional parameters of a three-dimensional woven composite material at a spatial location The initial values ​​are as follows: the initial thickness of the diaphragm is 4 mm and the initial thickness of the intermediate shaft is 10 mm.

[0087] (2) Macroscopic finite element model of coupling, such as Figure 6 As shown.

[0088] (3) The failure measurement cloud diagram obtained from the finite element analysis (stress intensity analysis) of the macroscopic finite element model under the design load of the coupling is as follows: Figure 7 As shown; the results of finite element analysis (modal analysis) of the macroscopic finite element model under the design load of the coupling are as follows. Figure 8 As shown.

[0089] In step S50, the model is optimized. The values ​​of each parameter are as follows:

[0090] (1) The Tsai-Hill failure index is used to determine whether the structure has failed, and the failure index threshold is set. Set to 1.0.

[0091] (2) Frequency requirements This includes design requirements for the frequencies corresponding to the first-order bending mode, first-order axial tension mode, first-order torsional mode, and first-order shear mode of the coupling. , , , The frequencies were set to 150Hz, 150Hz, 1000Hz, and 200Hz respectively.

[0092] (3) , , The values ​​are 30°, 40%, and 3mm, respectively; , , The values ​​are 70°, 60%, and 10mm.

[0093] In step S50, Latin hypercube sampling is performed on the aforementioned interval, and the mechanical response of the coupling at the sampling points is calculated according to the aforementioned analysis steps for couplings. Then, based on the calculation results, a surrogate model between the design parameters and the mechanical properties of the coupling is constructed. Finally, a genetic algorithm is used to solve for the design parameters, ultimately obtaining: braiding angle. 45°, dimensional parameters The thickness of the membrane disk is 3.6 mm and the thickness of the intermediate shaft is 10 mm, and the volume fraction of the fiber bundle is... The figure is 50%. The design of the coupling is now complete.

[0094] This test case then verifies the parameters of the aforementioned completed coupling design, and the verification process is the same as the design process in the embodiment.

[0095] in:

[0096] Based on the parameters of the coupling designed above, a representative volume element model is established again, in which the geometric model of the fiber bundle is as follows: Figure 9 As shown.

[0097] The re-established mesh model of the resin matrix and fiber bundles is as follows: Figure 10 As shown.

[0098] The stress contour plots and damage contour plots of the newly established representative volume element model obtained by applying test loads to the unit cells are as follows: Figure 11 As shown.

[0099] The recalculated macroscopic equivalent elastic modulus and equivalent macroscopic strength are shown in Table 2 below.

[0100] Table 2 (Recalculated macroscopic equivalent elastic modulus and equivalent macroscopic strength)

[0101]

[0102] Finally, the failure measurement contour plot obtained from the finite element analysis (stress intensity analysis) of the new macroscopic finite element model under the design load of the coupling is as follows: Figure 12 As shown; the results of finite element analysis (modal analysis) of the new macroscopic finite element model under the design load of the coupling are as follows. Figure 13 As shown.

[0103] Based on the above results, it can be seen that it fully conforms to the optimization model. This proves that the design was successfully completed.

[0104] Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for designing a three-dimensional braided composite coupling based on cross-scale analysis, comprising the following steps: a three-dimensional braided composite material used for manufacturing a coupling comprises a resin matrix and a fiber bundle of carbon fiber material as a braided material, the method comprises the following steps: S10, for different spatial positions of the coupling specifying the weaving angle of the fiber bundles in the initial microstructure model of the three-dimensional woven composite material for this position and the volume fraction so as to establish a number of different representative volume element models; S20, introducing the representative volume element model into a finite element pre-processing software, and applying a test load to obtain the stress and strain of each unit cell of the representative volume element model; S30, obtaining the spatial position of the coupling based on the volume average method according to the stress and strain of a plurality of said cells the macroscopic equivalent elastic modulus of the three-dimensional woven composite material at the position, predicting the spatial position of the coupling based on the Hashin progressive damage failure model the equivalent macroscopic strength of the three-dimensional woven composite material at the position; S40, establishing a macro finite element model of the coupling, defining size parameters of the three-dimensional woven composite material at a plurality of spatial positions of the macro finite element model of the coupling , subsequently assigning the macro equivalent elastic modulus and the equivalent macro strength to the macro finite element model, and finally performing finite element analysis of the macro finite element model under design load of the coupling;​ S50, adjusting , , and repeating steps S10-S40 and substituting the results of the finite element analysis into the optimization model solving to complete the design of the coupling, wherein represents a preset spatial position total number of denotes the design variables of the coupling obtained by solving, denotes the total mass of the coupling as a function of the design variables , , , denotes the optimization model with the total mass of the coupling as a design requirement minimizing the total mass of the coupling as a design requirement requirements representing constraints that the design variables obtained by solving need to satisfy, represents a failure index of the structure of the coupling with , , represents a natural frequency of the structure of the coupling with , , ​​ represents a failure index threshold, represents a frequency requirement, , , respectively denote a minimum value of the weaving angle, the volume fraction, the size parameter, , , respectively denote a maximum value of the weaving angle, the volume fraction, the size parameter. 2.The method for designing a three-dimensional braided composite coupling based on cross-scale analysis according to claim 1, wherein: wherein in step S20, the finite element pre-processing software comprises ABAQUS CAE or Hypermesh. 3.The method for designing a three-dimensional braided composite coupling based on cross-scale analysis according to claim 1, wherein: wherein, in step S20, the finite element pre-processing software performs finite element meshing on the representative volume element model and applies a periodic boundary condition. 4.The method for designing a three-dimensional braided composite coupling based on cross-scale analysis according to claim 3, wherein: wherein in step S20, the periodic boundary condition is realized by restraining the displacement of the corresponding nodes of the representative unit cell. 5.The method for designing a three-dimensional braided composite coupling based on cross-scale analysis according to claim 1, wherein: wherein in step S20, the test load comprises a tensile load, a compressive load, and a shear load.

6. The cross-scale analysis based three-dimensional woven composite couplings design method of claim 1, wherein, in step S40, performing the finite element analysis of the macroscopic finite element model under the design load of the coupling comprises: applying a torsional load to the macroscopic finite element model to perform stress intensity analysis to obtain a failure index of the structure of the coupling under the design load; and performing modal analysis on the macroscopic finite element model to obtain the natural frequencies of each order of the coupling. 7.The method for designing a three-dimensional braided composite coupling based on cross-scale analysis according to claim 1, wherein: 8.The method for designing a three-dimensional braided composite coupling based on cross-scale analysis according to claim 1, wherein: wherein In steps S10-S50, the weaving angle The corresponding weaving mode of the fiber bundle includes three-dimensional four-way weaving and three-dimensional five-way weaving. 9.The method for designing a three-dimensional braided composite coupling based on cross-scale analysis according to claim 8, wherein: wherein In step S50, the adjustment of the heuristic algorithm and the solving of the optimization model are performed , , . in step S50, the heuristic algorithm comprises a genetic algorithm or a particle swarm algorithm. wherein The method for designing a three-dimensional braided composite coupling based on cross-scale analysis according to any one of claims 1 to 9 comprises:

10. A system for designing a three-dimensional braided composite material coupling based on a cross-scale analysis, characterized in that, a finite element pre-processing module for introducing the representative volume element model into a finite element pre-processing software, and applying a test load to obtain the stress and strain of each unit cell of the representative volume element model; and a modeling module for different spatial positions of the coupling for the user to specify the fiber bundle weaving angles in the initial microstructure model of the three-dimensional woven composite material for the position and volume fraction to establish a number of different representative volume element models; ​ a macro performance calculation module for obtaining the macro equivalent elastic modulus of the three-dimensional braided composite material at the spatial position of the coupling based on the Hashin progressive damage failure model a macro performance calculation module for obtaining the macro equivalent elastic modulus of the three-dimensional braided composite material at the spatial position of the coupling based on the Hashin progressive damage failure model a macro performance calculation module for obtaining the macro equivalent elastic modulus of the three-dimensional braided composite material at the spatial position of the coupling based on the Hashin progressive damage failure model The coupling macroscopic analysis module is used to establish a macroscopic finite element model of the coupling, which is then used by the user to define the macroscopic finite element model of the coupling in the [missing information]. dimensional parameters of the three-dimensional woven composite material at each spatial location Then, the macro equivalent elastic modulus and the equivalent macro strength are assigned to the macro finite element model, and finally, the macro finite element model is subjected to finite element analysis under the design load of the coupling. a design evaluation and iteration module for adjusting , , After repeating the functions of the modeling module, the finite element pre-processing module, the macro performance calculation module and the coupling macro analysis module, the results of the finite element analysis are substituted into the optimization model to solve and complete the design of the coupling.

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