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

Abstract

The application 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. The application establishes a representative volume element model with a specific braiding angle and fiber volume fraction for different spatial positions of the coupling; through finite element analysis and volume averaging method, the macroscopic equivalent elastic modulus and strength of each position are obtained; then a macroscopic finite element model of the coupling is established, and the equivalent performance parameters are given to analyze the failure index and natural frequency of the coupling under the design load; taking the minimization of the mass as the target, and taking the failure index and natural frequency as the constraints, an optimization model is constructed, and the braiding angle, volume fraction and structure size are iteratively adjusted through a heuristic algorithm to realize the lightweight and performance collaborative optimization of the coupling. The application solves the design problems caused by the multiple parameters and strong multi-scale coupling of the three-dimensional braided coupling, and can efficiently and automatically obtain an optimized design scheme meeting the requirements of complex working conditions.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of digital data processing, and relates to a method using finite elements in computer-aided design, to design optimization, verification or simulation, to composite materials, and in particular to a three-dimensional woven composite material coupling device design method and system based on cross-scale analysis. BACKGROUND

[0002] As a key basic component in mechanical transmission system, coupling device is mainly used to connect two shafts to rotate together to transmit torque and motion. Traditional coupling devices are mostly made of metal materials, such as 45 steel, aluminum alloy, stainless steel, etc. Although metal coupling devices are widely used, with the increasing demand for lightweight of modern high-end equipment and the continuous improvement of the use environment, the lower stiffness ratio, strength ratio and corrosion resistance of metal materials limit their application range. In order to overcome these defects, composite material coupling devices have emerged.

[0003] Composite materials provide a new way for the performance improvement of coupling devices due to their high specific strength, high specific modulus, strong designability, fatigue resistance and corrosion resistance. Composite material coupling devices have appeared in the prior art, for example, Liu Changxi designed a composite material high compensation flexible membrane disc coupling in Chinese patent application CN108087442A, and gave the corresponding design method in Chinese patent application CN108595724A. However, this kind of composite material coupling device is mainly manufactured based on the form of lay-up, and the design process mainly focuses on the macro size and lay-up sequence of the component. Although the lay-up composite material coupling device realizes lightweight to some extent, it has the inherent defect of weak interlaminar performance, which is easy to cause interlaminar delamination when subjected to impact or complex alternating load, leading to progressive damage of the structure during continuous torque transmission and limiting the reliability.

[0004] In recent years, three-dimensional woven composite materials form a whole fibrous network structure by interweaving in X, Y and Z directions, which significantly improves the performance of composite materials in the thickness direction, making it reach the level of in-plane performance, so as to fundamentally solve the problems of weak interlaminar performance and poor impact resistance of traditional lay-up composite materials. However, the advantages of three-dimensional woven composite materials in structural performance depend highly on the mesoscopic design parameters such as weaving angle and fiber volume fraction. Compared with lay-up composite materials, three-dimensional weaving has higher design parameter freedom and more complex spatial distribution, which leads to greater challenges in the cross-scale design and performance optimization of three-dimensional woven composite material coupling devices. How to effectively associate and cooperatively optimize the mesoscopic weaving parameters and macroscopic component performance has become a key problem in the design of three-dimensional woven composite material coupling devices.

[0005] At present, there are some related researches on multi-scale design and optimization of composite structures:

[0006] (1) Chinese patent application CN115238555A discloses a three-dimensional woven composite thin-walled structure multi-scale analysis method based on local homogenization. This method improves the calculation efficiency by establishing a meso-cell model and performing local homogenization processing. However, this method mainly focuses on the mechanical property prediction of thin-walled structures, and does not involve how to couple the meso-design parameters (such as weaving angle, volume fraction) with the multi-objective performance of macro components (such as torque transmission ability, vibration characteristics, lightweight), nor does it consider the dynamic load and reliability constraints specific to couplings in the optimization framework, so it is difficult to directly guide the systematic design of three-dimensional woven 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” provides a carbon fiber reinforced composite drive shaft design method based on multi-scale reliability optimization. This method introduces optimization strategies such as particle swarm algorithm to automatically optimize the layer composite material, and makes progress in achieving lightweight and reliability balance. However, there are essential differences between drive shafts and couplings in terms of function and core stress state in the transmission system. The drive shaft mainly bears pure torsional load and dynamic balance under high-speed rotation, and the design focus is on torsional stiffness, critical speed and axial strength. The core function of the coupling is to connect two shafts and compensate for the radial, axial and angular deviations that exist in the installation, and its working condition is more complex. In addition to transmitting torque, it also needs to bear additional bending moment, radial force and other combined loads caused by misalignment, so the design of the coupling must balance multiple intercoupled objectives such as torsional performance, multi-directional compensation ability, fatigue life and specific vibration mode suppression. Directly applying the optimization model and failure criteria established for the drive shaft, which focuses on pure torsion as the core constraint, to the design of three-dimensional woven composite couplings, is difficult to fully evaluate their comprehensive performance and failure risk under real complex working conditions. In addition, the optimization framework of this method mainly focuses on layer composite materials, while three-dimensional woven composite materials have more complex spatial interweaving characteristics and more diverse meso-design variables (weaving angle, fiber volume fraction, spatial gradient distribution, etc. with strong coupling influence of multiple parameters), which have significant differences in design paradigm. Therefore, the optimization strategy based on the layer assumption has the problems of insufficient model adaptability and difficulty in effectively coordinating the strong coupling relationship of multiple parameters when applied to three-dimensional woven 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 , , and repeating steps S10-S40, and substituting several results of the finite element analysis into the optimization model solving to complete the design of the coupling, wherein represents a preset spatial position represents the total number of represents a design variable of the coupling obtained by solving, represents a function of the total mass of the coupling with , , as design variables, represents that the optimization model is designed to minimize the total mass of the coupling as an objective, represents a requirement that the design variable obtained by solving needs to meet the constraint condition, represents a failure index of the structure of the coupling with , , as design variables, represents a natural frequency of the structure of the coupling with , , as design variables, represents a failure index threshold value, represents a frequency requirement, , , respectively represent the minimum values of the weaving angle, the volume fraction, and the size parameter, , , respectively represent the maximum values of the weaving angle, the volume fraction, and the size parameter.

[0014] In the three-dimensional braided composite coupling design method based on cross-scale analysis provided by the application, the finite element pre-processing software in step S20 can include ABAQUS CAE or Hypermesh.

[0015] In the three-dimensional braided composite coupling design method based on cross-scale analysis provided by the application, the finite element pre-processing software in step S20 can include ABAQUS CAE or Hypermesh.

[0016] In the three-dimensional braided composite coupling design method based on cross-scale analysis provided by the application, the periodic boundary condition in step S20 can be realized by constraining the displacement of the corresponding nodes of the representative unit cell.

[0017] In the three-dimensional braided composite coupling design method based on cross-scale analysis provided by the application, the test load in step S20 can further include tensile, compression and shear loads.

[0018] In the three-dimensional braided composite coupling design method based on cross-scale analysis provided by the application, the finite element analysis of the macro finite element model under the design load of the coupling in step S40 can further include: applying a torsional load to the macro 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 macro finite element model to obtain the natural frequencies of each order of the coupling.

[0019] In the three-dimensional braided composite coupling design method based on cross-scale analysis provided by the application, the braiding angle of the fiber bundle in steps S10-S50 can be further determined according to the spatial position of the coupling. The corresponding braiding mode of the fiber bundle includes three-dimensional four-way braiding and three-dimensional five-way braiding.

[0020] In the three-dimensional braided composite coupling design method based on cross-scale analysis provided by the application, the adjustment and optimization model in step S50 can further include the adjustment and optimization model of the following formula. 、 、 .

[0021] In the three-dimensional braided composite coupling design method based on cross-scale analysis provided by the application, the heuristic algorithm in step S50 can further include a genetic algorithm and a particle swarm algorithm.

[0022] The application further provides a three-dimensional braided composite coupling design system based on cross-scale analysis, which uses any of the three-dimensional braided composite coupling design methods based on cross-scale analysis provided by the application and includes: a modeling module for specifying the braiding angle and volume fraction of the fiber bundle in the initial microstructure model of the three-dimensional braided composite material at different spatial positions of the coupling by a user to establish a plurality of different representative volume element models; a finite element pre-processing module for importing the representative volume element models into a finite element pre-processing software for processing, applying test loads to the models to obtain the stress and strain of each unit cell of the plurality of representative volume element models; and a macro performance calculation module for obtaining the stress and strain of the plurality of unit cells, and obtaining the spatial positions of the coupling based on the volume average method. ​​​The macroscopic equivalent elastic modulus of the three-dimensional woven composite material at the spatial position of the coupling The equivalent macroscopic strength of the three-dimensional woven composite material at the spatial position of the coupling The size parameters of the three-dimensional woven composite material at the spatial position of the coupling The macroscopic equivalent elastic modulus and the equivalent macroscopic strength are assigned to the macroscopic finite element model, and finally the finite element analysis of the macroscopic finite element model under the design load of the coupling is performed 、 、 The results of the finite element analysis are substituted into the optimization model to solve the design of the coupling.

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

[0024] (1) The present application designs a composite coupling by introducing a three-dimensional woven composite material, greatly improving the interlaminar performance of the coupling and effectively resisting the delamination failure of the composite material. A systematic design framework for the three-dimensional woven composite coupling is provided, which combines the unique mesoscopic design variables (weaving angle, fiber volume fraction) of the three-dimensional woven composite material with the macroscopic structure size of the coupling for joint design and optimization, effectively solving the problems faced by the three-dimensional woven composite material in the design of the coupling due to its high degree of freedom, filling the gap of systematic design method in this field, and expanding the design space of the coupling compared with the traditional single-level design due to the scale synergy advantage.

[0025] (2) The present application can more accurately reflect the influence of the gradient change of the three-dimensional woven composite structure space on the overall performance by establishing multiple representative volume element models for different spatial positions of the coupling and obtaining the equivalent macroscopic performance based on finite element analysis and volume averaging method. Combined with the Hashin progressive damage failure model, the failure risk of the key position of the coupling can be quantitatively predicted, providing a reliable performance evaluation basis for optimization design, and finally realizing high-precision cross-scale performance prediction.

[0026] (3) The present application takes the minimization of the total mass of the coupling as the core target, and takes the failure index and the natural frequency of the structure as the key constraint conditions, establishes a special optimization model that fits the working condition of the coupling. The optimization results are highly consistent with the engineering actual demand, overcoming the limitations of directly applying the optimization model of simple torsion members such as driving shafts.

[0027] (4) The application realizes the automation of the design process by automatically substituting the finite element analysis results into the parameterized optimization model and automatically adjusting the meso-weaving parameters and macro-size by using a heuristic algorithm, can efficiently explore a complex multi-variable design space, converges to the optimal solution of lightweighting under the premise of guaranteeing performance constraints, greatly reduces the time and labor cost required by the traditional trial-and-error method, and significantly improves the design efficiency and automation level of the three-dimensional woven composite material coupling.

[0028] (5) In the optimization process, the application sets reasonable upper and lower limits for the weaving angle, volume fraction and size parameters, and considers the specific weaving methods such as three-dimensional four-way and five-way, so as to ensure that the final optimization design scheme obtained is implementable under the existing three-dimensional weaving process conditions. The optimization results based on the failure index and natural frequency constraints guarantee the structural safety and dynamic stability of the coupling in use from the source of design.

[0029] (6) The application can realize the maximum lightweighting of the structure under the premise of meeting all the mechanical properties (strength, stiffness) and dynamic characteristics (natural frequency) of the coupling. Compared with the traditional metal coupling or the composite material design scheme relying on experience, the application can find the maximum performance of the three-dimensional woven composite material coupling, realize the dual goals of weight reduction and performance improvement, and achieve significant lightweighting effect and comprehensive performance improvement. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a three-dimensional woven composite material coupling design method flow chart based on cross-scale analysis of an embodiment of the application.

[0031] Figure 2 is an architecture diagram of a three-dimensional woven composite material coupling design system based on cross-scale analysis of an embodiment of the application.

[0032] Figure 3 is a geometric model of a fiber bundle in a representative volume element model of a test example of the application.

[0033] Figure 4 is a mesh model of a representative volume element model processed by a finite element pre-processing software in a test example of the application, wherein the part (a) is a mesh model of a fiber bundle, and the part (b) is a mesh model of a resin matrix.

[0034] Figure 5 is a stress and damage cloud chart of a unit cell in a test example of the application.

[0035] Figure 6 is a macro finite element model in a test example of the application.

[0036] Figure 7is the failure measure contour map obtained by the finite element analysis (stress intensity analysis) of the macro finite element model in the test example of the present application under the design load of the coupling.

[0037] Figure 8 is the result schematic diagram obtained by the finite element analysis (modal analysis) of the macro finite element model in the test example of the present application under the design load of the coupling.

[0038] Figure 9 is the geometric model of the fiber bundle in the newly established representative volume element model in the verification process of the test example of the present application.

[0039] Figure 10 is the grid model of the representative volume element model processed by the finite element pre-processing software in the verification process of the test example of the present application, wherein, (a) part is the grid model of the fiber bundle, and (b) part is the grid model of the resin matrix.

[0040] Figure 11 is the stress contour map and damage contour map of the unit cell of the newly established representative volume element model in the verification process of the test example of the present application.

[0041] Figure 12 is the failure measure contour map obtained by the finite element analysis (stress intensity analysis) of the new macro finite element model in the verification process of the test example of the present application under the design load of the coupling.

[0042] Figure 13 is the result schematic diagram obtained by the finite element analysis (modal analysis) of the new macro finite element model in the verification process of the test example of the present application under the design load of the coupling. DETAILED DESCRIPTION

[0043] In order to make the technical means, creative features, purposes and effects realized by the present application easy to understand, the following embodiments will make a specific description of the three-dimensional woven composite coupling design method and system based on cross-scale analysis of the present application in combination with the accompanying drawings.

[0044] EMBODIMENT

[0045] The embodiment provides a three-dimensional woven composite coupling design method based on cross-scale analysis. The three-dimensional woven composite material used for manufacturing the coupling comprises a resin matrix and a fiber bundle of carbon fiber material as a woven material in the resin matrix.

[0046] Figure 1 is the flowchart of the three-dimensional woven composite coupling design method based on cross-scale analysis of the embodiment of the present application.

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

[0048] S10, modeling a representative volume element model:

[0049] for different spatial positions of the coupling , specifying the braiding angle of the fiber bundle in the initial microstructure model of the three-dimensional braided composite material at the position and the volume fraction , thereby establishing a plurality of different representative volume element models.

[0050] wherein the braiding angle corresponding to the braiding mode of the fiber bundle includes three-dimensional four-way braiding and three-dimensional five-way braiding.

[0051] S20, finite element pre-processing of the representative volume element model:

[0052] After importing the representative volume element model into the finite element pre-processing software ABAQUS CAE for finite element meshing and applying the periodic boundary condition realized by constraining the displacement of the nodes of the representative unit, a test load (tensile, compressive and shear load) is applied to obtain the stress and strain of the unit of each representative volume element model.

[0053] S30, calculating the macroscopic performance of each spatial position of the coupling:

[0054] According to the stress and strain of the unit, the macroscopic equivalent elastic modulus of the three-dimensional braided composite material at the spatial position of the coupling is obtained based on the volume average method; and the equivalent macroscopic strength of the three-dimensional braided composite material at the spatial position of the coupling is predicted based on the Hashin progressive damage failure model.

[0055] S40, cross-scale finite element modeling and analysis of the coupling:

[0056] A macroscopic finite element model of the coupling is established, the size parameters of the three-dimensional braided composite material at the first spatial position of the macroscopic finite element model of the coupling are defined , then the macroscopic equivalent elastic modulus and the equivalent macroscopic strength calculated in step S30 are assigned to the macroscopic finite element model, and finally the finite element analysis of the macroscopic finite element model under the design load of the coupling is performed, including applying a torsional load to the macroscopic finite element model to perform stress strength 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 frequency of each order of the coupling.

[0057] S50, design evaluation and iteration:

[0058] using a heuristic algorithm (in this embodiment, a genetic algorithm is specifically selected) , , and repeating steps S10-S40, and then substituting the results of the finite element analysis obtained in step S40 into the optimization model to solve, thereby completing the design of the coupling.

[0059] In the above optimization model, denotes the total number of preset spatial positions , denotes the design variables of the coupling obtained by solving, denotes a function of the total mass of the coupling , , with the design variables, denotes that the optimization model is designed to minimize the total mass of the coupling , denotes the requirement that the design variables obtained by solving need to meet the constraint conditions, denotes the failure index of the structure of the coupling , , with the design variables, denotes the natural frequency of the structure of the coupling , , with the design variables, denotes the failure index threshold, denotes the frequency requirement, , , respectively denote the minimum values of the weaving angle, volume fraction, and size parameter, , , respectively denote the maximum values of the weaving angle, volume fraction, and size parameter.

[0060] Figure 2 is the architecture diagram of the three-dimensional braided composite coupling design system based on cross-scale analysis according to an embodiment of the present application.

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

[0062] The modeling module 10 is configured to create a plurality of representative volume element models in a manner according to step S10, for different spatial locations of the coupling , for which the user specifies the weaving angle and volume fraction of the fiber tows in the initial microstructure model of the three-dimensional woven composite material of the location , thereby establishing a plurality of representative volume element models. The finite element pre-processing module 20 is configured to import the representative volume element models into a finite element pre-processing software and apply test loads to obtain the stress and strain of the unit cells of the representative volume element models in a manner according to step S20.

[0063] The macroscopic performance calculation module 30 is configured to obtain the macroscopic equivalent elastic modulus of the three-dimensional woven composite material at the spatial location of the coupling

[0064] , based on the volume average method according to the stress and strain of the unit cells, and predict the equivalent macroscopic strength of the three-dimensional woven composite material at the spatial location of the coupling , based on the Hashin progressive damage failure model, in a manner according to step S30. The coupling macroscopic analysis module 40 is configured to establish a macroscopic finite element model of the coupling and define the size parameters of the three-dimensional woven composite material at the first spatial location of the macroscopic finite element model of the coupling

[0065] by the user in a manner according to step S40, then assign the macroscopic equivalent elastic modulus and the equivalent macroscopic strength to the macroscopic finite element model, and finally perform finite element analysis of the macroscopic finite element model under the design load of the coupling. The design evaluation and iteration module 50 is configured to adjust ,

[0066] , , , and repeat the functions of the modeling module 10, the finite element pre-processing module 20, the macroscopic performance calculation module 30, and the coupling macroscopic analysis module 40, and then substitute a plurality of results of the finite element analysis into an optimization model to solve the coupling design.

[0067] Test Example

[0068] The test example uses the three-dimensional woven composite coupling design system 100 based on the cross-scale analysis in the embodiment to design a coupling according to the three-dimensional woven composite coupling design method based on the cross-scale analysis in the embodiment.

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

[0070] (1) No damage occurs at 500

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

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

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

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

[0075] In order to design the above-mentioned coupling:

[0076] In step S10, the weaving manner of the fiber bundle in the initial microstructure model is specified as three-dimensional four-way weaving, and the initial values of the weaving angles at different spatial positions are first uniformly set to 60°, and the initial values of the volume fractions are uniformly set to 50%. The obtained representative volume element model includes a resin matrix and a fiber bundle of carbon fiber material as the weaving material in the resin matrix, and the geometric model of the fiber bundle is as shown in . Figure 3 In step S20:

[0077] (1) The grid model of the fiber bundle and the resin matrix after processing by the finite element pre-processing software is as shown in

[0078] . Figure 4 (2) The stress and damage cloud maps of the unit cell obtained by applying the test load to the unit cell of the representative volume element model are as shown in

[0079] . Figure 5 In step S30:

[0080] The calculated macroscopic equivalent elastic modulus and equivalent macroscopic strength are shown in Table 1 below.

[0081] Table 1 (macroscopic equivalent elastic modulus and equivalent macroscopic strength)

[0082]

[0083] In Table 1 above,

[0084] represents the elastic modulus in the 1 direction, represents the elastic modulus in the 2 direction, represents the primary Poisson's ratio, represents the secondary Poisson's ratio, represents the in-plane shear modulus, represents the out-of-plane shear modulus, ​​tensile strength in the 1 direction, compressive strength in the 1 direction, tensile strength in the 2 direction, compressive strength in the 2 direction, in-plane shear strength, out-of-plane shear strength.

[0085] In step S40:

[0086] (1) The initial value of the size parameter of the three-dimensional woven composite material at the 1st space position of the macro finite element model of the coupling is specifically: the initial thickness of the diaphragm is 4mm, and the initial thickness of the intermediate shaft is 10mm.

[0087] (2) The macro finite element model of the coupling is as shown in Figure 6 .

[0088] (3) The failure measurement cloud diagram obtained by the finite element analysis (stress strength analysis) of the macro finite element model under the design load of the coupling is as shown in Figure 7 ; the result obtained by the finite element analysis (modal analysis) of the macro finite element model under the design load of the coupling is as shown in Figure 8 .

[0089] In step S50, the values of each parameter of the optimization model are respectively:

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

[0091] (2) The frequency requirement includes the design requirements of the frequencies corresponding to the first-order bending mode, the first-order axial tensile mode, the first-order torsional mode, and the first-order shear mode of the coupling , , , , which are respectively set to 150Hz, 150Hz, 1000Hz, and 200Hz.

[0092] (3) , , The values of , , are respectively 30°, 40%, and 3mm; ,

[0093] In step S50, Latin hypercube sampling is performed for the above interval, and the mechanical response of the coupling at the sampling points is calculated according to the analysis steps of the coupling. Then, based on the calculation results, a surrogate model of the design parameters and the mechanical properties of the coupling is constructed. Finally, the design parameters are solved by using a genetic algorithm, and finally the weaving angle is 45°, the size parameter is the film disc thickness 3.6mm and the intermediate shaft thickness 10mm, the volume fraction of the fiber bundle is 50%. Finally, the design of the coupling is completed.

[0094] The test example then verifies the parameters of the coupling designed as described above, and the verification process is the same as the design process in the embodiment.

[0095] Wherein:

[0096] Based on the parameters of the coupling designed as described above, a representative volume unit model is established again, wherein the geometric model of the fiber bundle is as shown in Figure 9 .

[0097] The grid model of the resin matrix and the fiber bundle established again is as shown in Figure 10 .

[0098] The stress and damage contours of the unit cell obtained by applying a test load to the unit cell of the newly established representative volume unit model are as shown in Figure 11 .

[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 measure contour obtained by the finite element analysis (stress intensity analysis) of the new macroscopic finite element model under the design load of the coupling is as shown in Figure 12 ; the results obtained by the finite element analysis (modal analysis) of the new macroscopic finite element model under the design load of the coupling are as shown in Figure 13 .

[0103] Based on the above results, it can be known that it fully meets the optimization model , proving that the design is successfully completed.

[0104] Those skilled in the art should understand that the present application is not limited to the above-mentioned embodiments, and the above-mentioned embodiments and descriptions in the specification are only to illustrate the principles of the present application, and various changes and improvements can be made without departing from the spirit and scope of the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application 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 braiding angle, the volume fraction, the size parameter, , , respectively denote a maximum value of the braiding 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 macroscopic equivalent elastic modulus and the 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. 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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