A parameterized modeling method of woven composite material

Abstract

The present application relates to the technical field of aero-engine outer casing design engineering simulation, and particularly relates to a parameterized modeling method of woven composite materials, which is based on TexGen open source software developed by the University of Nottingham, adopts a Python language interface provided by TexGen, takes fiber volume fraction, weaving angle and axial cross-sectional size factor as basic parameters of input variable parameters, and realizes parameterized modeling in combination with yarn trajectory and coordinates. The modeling process comprises the following steps: analyzing a weaving process, determining the number relationship of weaving yarn and axial yarn and the movement law of a yarn carrier; analyzing the in-plane and spatial movement law of yarn, determining internal weaving angle, surface weaving angle and the spatial orientation of various yarns; selecting an internal cell configuration and a surface cell configuration based on a mesoscopic hypothesis; calculating a single cell geometric parameter to determine the relationship between internal weaving angle and weaving angle; adopting linear interpolation fitting trajectory in TexGen, giving a cross-sectional shape, and establishing a parameterized mesoscopic single cell three-dimensional geometric model.

Description

Technical Field

[0001] This invention relates to the field of simulation technology for the design of aero-engine bypass casings, and specifically to a parametric modeling method for woven composite materials. Background Technology

[0002] In the aerospace field, multifunctional lightweight materials and structures have always been a key focus in design and manufacturing. With the continuous advancement of aerospace technology, increasingly stringent requirements are being placed on the structural performance and weight of aircraft and their engines. To meet these requirements, exploring and researching new materials and structures that combine high performance and lightweight design has become a crucial direction for continuous innovation.

[0003] Braided composite materials are formed by interlacing multiple bundles of fiber yarns in space. They have excellent specific strength, specific modulus, impact toughness and designability. In recent years, they have been gradually applied to the manufacture of key components of aero-engines (such as turbine blades) and structural components of aircraft (such as fuselage skin and solar panels), demonstrating their broad application prospects and continuous innovation potential in the aerospace field.

[0004] However, woven composite materials exhibit complex microstructures formed by interwoven yarns in their internal, surface, and angular regions. Due to the complex and varied interweaving paths of the yarns in space, accurately simulating the spatial orientation and solid structure of the internal yarns becomes a significant technical challenge when using the finite element method for modeling and simulation analysis. Traditional 3D modeling software such as Solidworks, UG, and CATIA employs a point-line-surface solid modeling approach. When dealing with structures like woven composite materials where the yarn trajectory is a complex spatial polygonal line, the modeling process is extremely cumbersome. Designers must define the path nodes of hundreds of yarns one by one, resulting in a large workload and a high risk of errors. More importantly, in dense areas where multiple yarns intersect in space, using simplified or fitted paths easily leads to geometric interference between yarn entities in the model, failing to accurately reflect the material's internal microstructure. This oversimplified geometric model directly results in inaccurate predictions of macroscopic mechanical properties such as material stiffness and strength during subsequent finite element simulations, severely impacting the design accuracy and reliability assessment of critical structural components such as the outer bypass casing of aero-engines.

[0005] Therefore, there is an urgent need for a parametric modeling method that can accurately describe the spatial orientation of yarns inside woven composite materials, effectively avoid yarn interference, and has high modeling efficiency. This method would overcome the shortcomings of existing technologies, such as cumbersome modeling processes, low model accuracy, and inability to accurately predict mechanical properties. In this way, it would provide a high-fidelity digital modeling tool for the design, material selection, and structural simulation of composite material components. Summary of the Invention

[0006] The purpose of this invention is to provide a parametric modeling method for woven composite materials, which overcomes the shortcomings of existing modeling techniques, such as cumbersome modeling process, easy yarn interference, and inaccurate internal structure simulation leading to low accuracy in mechanical property prediction.

[0007] To achieve the above objectives, this invention proposes a parametric modeling method for woven composite materials, comprising the following steps: S1. Analyze the weaving process to determine the quantitative relationship between the weaving yarn and the axial yarn, as well as the motion law of the yarn carrier. S2. Analyze the movement patterns of yarns in the plane and in space to determine the spatial orientation of internal braided yarns, surface braided yarns, and axial yarns. S3. Based on the assumption of microstructure, intracellular configuration and cellular configuration are selected as modeling objects; S4, according to the weaving angle Axial section size factor Calculate the geometric structural parameters of the inner cell configuration and the face cell configuration; S5. Using the Python language interface provided by the TexGen open-source software, the fiber volume fraction... , woven corner Axial section size factor Using basic parameters as input variables for parameterization, combined with yarn trajectory and coordinates, a three-dimensional geometric model of the micro-unit cell of woven composite materials is established.

[0008] Furthermore, the weaving process is a three-dimensional five-directional weaving process or a three-dimensional full five-directional weaving process. The three-dimensional five-directional weaving process is an improvement based on the four-step 1×1 weaving process, in which an axial yarn carrier is added between each row of yarn carriers. The three-dimensional full five-directional weaving process is in which an axially stationary yarn carrier is added between adjacent rows in the three-dimensional five-directional weaving process. The axially stationary yarn carrier remains stationary throughout the entire weaving process.

[0009] Furthermore, for the three-dimensional five-directional weaving process, the total number of weaving yarns... Total number of axial yarns and total number of yarns satisfy: ; ; ; For three-dimensional five-directional weaving technology, the total number of weaving yarns Total number of axial yarns Total number of yarns that remain stationary along the axis and total number of yarns satisfy: ; ; ; ; In the formula, and These represent the number of rows and columns of the main yarn being woven, respectively.

[0010] Furthermore, the analysis of yarn movement patterns includes: the in-plane movement trajectory of the braided yarn carrier is zigzag-shaped; the axial yarn carrier moves only along the row direction and not along the column direction; the surface braided yarn carrier stops one step after reaching the surface from the inner region and then returns to the inner region; the inner braided yarn extends one-quarter of the knot height in the z-direction after each process step in space, and after the tightening process, the yarn trajectory in space is a straight line, located in two sets of orthogonal planes at ±45° to the cross-section of the braided preform, and the angle with the z-direction is the inner braiding angle. The spatial trajectory of the axial yarn is a straight line parallel to the z-axis, passing through the midpoint of the axial yarn carrier position point; the spatial trajectory of the surface-knitted yarn is defined by two straight line segments, the angle between the straight line segments and the yarn axial direction is defined as the surface knitting angle. .

[0011] Furthermore, the internal braided angle With woven corner The relationship is: ; In the formula, the weaving angle Defined as the angle between the surface yarn texture formed by the arrangement of adjacent unidirectional braided yarns on the surface of the specimen and the braiding direction z.

[0012] Furthermore, the assumptions regarding the microstructure include: the braided yarns within the unit cell extend linearly in space, taking into account the tightening during the braiding process and the compression of adjacent yarns; the cross-sectional shape of the braided yarn is elliptical, defined using the powerellipse section in TexGen, with the power parameter P set to 0.5 to make the cross-section elliptical, with the major and minor axes being respectively... and The relationship between the two is as follows: ,in: The internal braiding angle is defined as follows: the axial yarn is a straight line parallel to the z-axis of space, with a square cross-section and the parallel sides of the cross-section forming ±45° with the cross-section of the preform; the braiding process is stable, the mechanical properties of the yarn are not damaged, and the uniformity of the braided parts is maintained.

[0013] Furthermore, the geometric parameters of the inner cell configuration include width. ,thickness and height , respectively represented as: ; ; ; The geometric parameters of the cell configuration include width ,thickness , respectively represented as: ; ; ; In the formula, For internal braided corners, This is the axial section size factor. The short semi-axis when the cross-sectional shape of the braided yarn is elliptical; The factor representing the reduction ratio of the cross-sectional area of ​​the face cell; For surface weaving angles.

[0014] Furthermore, the proportions of inner cells, face cells, and corner cells in the three-dimensional braided composite material are calculated using the following formula: ; In the formula, These represent the volume fractions of each region in the entire composite material structure, namely, the inner cell, the face cell, and the corner cell. This is the axial section size factor; and These represent the number of rows and columns of the main yarn being woven, respectively. This represents the fiber volume fraction. This indicates the volume fraction of fibers in the inner cells; This indicates the volume fraction of fibers in the face cells; This indicates the volume fraction of fibers in the cell.

[0015] Furthermore, establishing the three-dimensional geometric model of the micro-cell includes: defining the coordinates of the feature nodes of the yarn using functions; for the inner cell configuration, the yarn trajectory is a straight line, defined by two principal nodes; for the face cell configuration, the yarn trajectory consists of multiple segments of broken lines, with nodes defined at the turning points of each broken line; fitting the yarn trajectory using a linear interpolation method; defining the yarn segment resolution using Set Resolution, with 40 segment points; and assigning cross-sectional shape and size to the woven yarn at the feature nodes to define the yarn cross-section.

[0016] Furthermore, for the inner cell configuration, the coordinates and cross-sectional information of four basic braided yarns and one axial yarn are defined. The addrepeat instruction is used to copy and translate the four basic braided yarns and axial yarns with different orientations. Then, the segmentation domain is defined to obtain the three-dimensional geometric model of the inner cell. For the face cell configuration, the feature nodes and cross-sectional information of two outer braided yarns and one axial yarn are defined. The face cell three-dimensional geometric model is obtained through the repeat instruction and region segmentation.

[0017] Due to the adoption of the above technical solution, the beneficial effects of the present invention are as follows: (1) High modeling accuracy: This invention fully considers the microstructure characteristics of braided composite materials, accurately describes the spatial orientation of internal braided yarns, axial yarns and surface braided yarns, and adopts the real yarn cross-sectional shape and trajectory, avoiding the oversimplification of microstructure in traditional modeling methods, and improving the realism of the model and the accuracy of mechanical performance prediction.

[0018] (2) High modeling efficiency: This invention achieves parametric modeling based on the TexGen open-source software and Python script interface. Users only need to input the fiber volume fraction. , woven corner Axial section size factor With just three basic parameters, the required 3D geometric model of a single cell can be automatically generated without manually defining the nodes and paths of each yarn, greatly improving modeling efficiency.

[0019] (3) Avoid yarn interference: By accurately calculating the coordinates of yarn feature nodes and using linear interpolation to fit the yarn trajectory, this invention can effectively control the relative position between yarns and avoid the yarn crossing and overlapping problem that is easy to occur in traditional manual modeling.

[0020] (4) Wide applicability: This invention is not only applicable to three-dimensional five-dimensional braided composite materials, but also to three-dimensional full five-dimensional braided composite materials. It can establish two microscale models, namely inner cell and surface cell, to meet the simulation needs of different regions.

[0021] (5) Integrated process: This invention establishes an adaptive mapping relationship between three-dimensional weaving process parameters and TexGen geometric model, realizing an integrated process of process parameter input, automatic modeling of material microstructure, and prediction of macroscopic mechanical properties, providing a high-precision and highly compatible digital development tool for the design, material selection, and structural optimization of composite material components such as the outer casing of aero-engines. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0023] Figure 1 This describes the workflow for TexGen microscopic unit cell modeling based on Python scripts.

[0024] Figure 2 This is a flowchart of the four-step weaving process.

[0025] Figure 3 This is the original diagram of the yarn carrier arrangement for a three-dimensional, five-directional weaving process.

[0026] Figure 4 This refers to the in-plane motion law of the yarn carrier.

[0027] Figure 5 The diagram shows the spatial movement of three-dimensional, five-directional knitting yarns, where: (a) the spatial direction of internal yarns; (b) the spatial direction of axial yarns; and (c) the spatial direction of surface yarns.

[0028] Figure 6 This is a PowerELlipse section.

[0029] Figure 7 Let be the projection of the yarn on the horizontal plane, where: (a) the unit cell of the three-dimensional five-directional braided structure is selected; (b) the unit cell of the three-dimensional full five-directional braided structure is selected.

[0030] Figure 8 The diagram shows the yarn topology, including: (a) a three-dimensional five-dimensional inner cell topology; (b) a three-dimensional fully five-dimensional inner cell topology; (c) a three-dimensional five-dimensional face cell topology; and (d) a three-dimensional fully five-dimensional face cell topology.

[0031] Figure 9 Define a flowchart for the yarn.

[0032] Figure 10 This is a schematic diagram of the yarn trajectory in a unit cell of a three-dimensional braided composite material.

[0033] Figure 11 This is a schematic diagram of the yarn trajectory of a three-dimensional braided composite material.

[0034] Figure 12 This is a microscopic geometric model of a three-dimensional braided composite material. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0036] Combination Figures 1 to 12 The image shows a specific embodiment of a parametric modeling method for woven composite materials provided by the present invention. The method includes the following steps: I. Analysis of Weaving Techniques The four-step 1×1 weaving process is the main preparation process for three-dimensional braided composite material preforms. The weaving machine chassis is equipped with a yarn carrier, and each yarn carrier carries a bundle of yarn. The yarn follows the machine chassis in a periodic four-step motion as the yarn carrier is pulled. After each cycle, a tightening process is performed to form a three-dimensional braided composite material with a knot length. By continuously cycling, the required three-dimensional braided composite material preform can be woven and formed, hence the name four-step weaving process.

[0037] The three-dimensional five-directional weaving process is an improvement on the four-step weaving process. Between the yarn carriers in each row, a yarn carrier for the axial yarn is added. These newly added axial yarns are wrapped by the surrounding weaving yarns, thus achieving the weaving shape.

[0038] Combination Figure 2 As shown, regarding the arrangement and movement of the braided yarn and axial yarn carriers, in the first step of the machine's movement, the braided yarn and axial yarn carriers of adjacent rows move alternately one position along the x-direction; in the second step, the braided yarn carriers of adjacent columns move alternately one position along the y-direction; the third step is the opposite of the first step; and the fourth step is the opposite of the second step. After one braiding cycle, the yarn carriers on the chassis return to their initial positions. Through the "tightening" process, tight contact is achieved between the braided yarns and between the braided yarns and the axial yarns. At this point, the preform of the three-dimensional braided composite material extends a height of [missing information] in the forming direction (z-direction) after one braiding cycle. The woven floral pattern is created through a four-step process and a "tightening" step, resulting in a preform of the three-dimensional woven composite material.

[0039] It should be noted that during the four-step motion process, the axial yarn carrier moves only along the row direction and not along the column direction.

[0040] Total number of woven yarns in woven prefabricated components Total number of axial yarns and total number of yarns satisfy: ; ; In the formula, and These represent the number of rows and columns of the main yarn in the weaving process. Therefore, the total number of yarns in the three-dimensional woven prefabricated component can be obtained. : .

[0041] Combination Figure 3 As shown, the three-dimensional full five-way weaving process adds axially stationary yarns between adjacent rows to the aforementioned three-dimensional five-way weaving process. The four-step movement pattern of the yarn carrier and the axial yarn carrier is exactly the same as in the three-dimensional five-way weaving process, while the axially stationary yarn carrier remains stationary throughout the entire weaving process. The difference between the two weaving processes is that the three-dimensional full five-way weaving process uses more axial yarn carriers than the three-dimensional five-way weaving process, which results in more axially stationary yarns filling the gaps in the three-dimensional five-way weaving structure that would otherwise be without a central axis. Let the total number of yarns in the three-dimensional full five-way rectangular weaving preform be... The total number of axial yarns is The total number of axially stationary yarns is Then we have: ; ; ; In the formula, and These represent the number of rows and columns of the main yarn being woven, respectively.

[0042] Similarly, the total number of yarns in the three-dimensional omnidirectional braided preform can be obtained. for: .

[0043] II. Analysis of yarn movement patterns The motion of yarn can be analyzed from two aspects: in-plane motion and spatial motion. In the weaving process of three-dimensional five-dimensional braided composite preforms, the in-plane motion trajectory of the yarn carrier resembles a "Z" shape, such as... Figure 4 As shown, taking the yarn carrier A as an example, after the yarn undergoes one cycle of movement and the "tightening" process, the yarn is taut inside the three-dimensional braided composite material due to the yarn tension. The projection of the yarn onto the surface is the line connecting the midpoints of adjacent points during the movement, as shown in the figure. Figure 4As shown in A'E', the axial yarn always moves only within the range of JL in the plane, and the midpoint K of JL is the projection of the axial yarn's trajectory in the horizontal plane. For the surface unit cell, the yarn carrier F of the surface braided yarn moves from the inner region to the surface and then back to the inner region throughout the entire braiding process. At H-H', the surface yarn carrier stops one step, which is also a factor that leads to the difference in spatial structure between the surface yarn and the inner yarn.

[0044] From the perspective of spatial motion, the internal weaving yarn extends by a quarter of the height of the flower knot in the z-direction of space for each step it undergoes in the process. That is... Figure 5 As shown in (a), the yarn moves from point A to point E in space, going through four steps. Under the influence of the tightening process and yarn tension, the yarn's trajectory in space is a straight line A'E', located in two sets of orthogonal planes at ±45° to the cross-section of the prefabricated body, with an angle of θ with the z-direction. , Defined as the internal braiding angle of a three-dimensional braided composite material unit cell model.

[0045] For the axial yarn of a three-dimensional five-axis braided composite material, since the axial yarn does not participate in the entire braiding process, the four-step movement of the axial yarn carrier Q always remains within the range of QR. Therefore, the spatial trajectory of the axial yarn is a straight line parallel to the z-axis and passes through the midpoint of the axial yarn carrier's position point, such as... Figure 5 As shown in (b). For surface-woven yarns, their spatial trajectory can be defined by two straight line segments, as follows: Figure 5 (c) shows F'H and HI'. The angle between the straight line segment F'H and the axial direction of the yarn is defined as the surface weave angle. The definition of the spatial trajectory of the braided yarn in three-dimensional omnidirectional braided composite materials is the same as that in three-dimensional pentaxial composite materials.

[0046] III. Selection and Assumptions of the Unit Cell Model To facilitate parametric modeling of the unit cell 3D geometric model, the following basic assumptions are made for the modeling of the mesoscopic model: (1) It is assumed that the braided yarns inside the unit cell extend in a straight line in space, taking into account the "tightening" in the braiding process and the compression of the braided yarns in other directions and the axial yarns. It is assumed that the cross-sectional shape of the internal braided yarn bundle is elliptical, and the major and minor axes are respectively and The relationship between the two is ,in: For internal braided corners.

[0047] (2) Assuming the cross-sectional shape of the braided yarn is elliptical, the powerellipse section is defined in TexGen. The cross-section of the powerellipse is defined by its width and height. The power parameter P controls the shape; when P < 1, the cross-section resembles a rounded rectangle, and when P > 1, the cross-section resembles a lenticular cross-section. The last parameter XOffset is optional; it is the offset from the center and specifies the maximum height of the shape. When the power parameter P is set to 0.5, the cross-section is elliptical. The axial yarn is a straight line parallel to the z-axis of space, and the cross-sectional shape is square. The parallel sides of the cross-section are at ±45° to the cross-section of the preform.

[0048] (3) The weaving process is stable, the mechanical properties of the yarn are not damaged, and the uniformity of the woven parts is maintained.

[0049] In three-dimensional five-dimensional and full five-dimensional braided structures, the projections of all yarns onto the xy-plane are as follows: Figure 7 As shown in the figure, the solid lines represent the braided yarns, and the axial yarns are evenly distributed among the braided yarns, with the braided yarns interlacing and wrapping around the axial yarns. This represents the horizontal orientation angle, under ideal conditions. =±45°. Inner cell configuration and face cell configuration are selected to describe the mechanical properties of three-dimensional braided composite materials.

[0050] Based on the fundamental assumptions of mesoscopic structure modeling and the spatial configuration of yarns in each region, structural parameters of the inner cell configuration and the face cell configuration can be obtained, serving as the basis for calculating the fiber volume content of the entire composite material structure and subsequently establishing a parametric solid structure model. In three-dimensional five-directional and all-five-directional woven composite material preforms formed through a four-step weaving process, the woven yarns intertwine with the axial yarns, extending and interweaving along multiple spatial directions to form an overall mesh structure. Based on the mesoscopic structure analysis of the three-dimensional five-directional and all-five-directional woven composite materials, the yarn topological relationships of the rectangular hexahedral inner cell configuration and the face cell configuration are obtained as follows: Figure 8 As shown. Further, based on the fundamental assumptions of the modeling, the relevant structural parameters are obtained.

[0051] IV. Analysis of unit cell geometric parameters The braid angle is a crucial structural parameter in braided composite materials. Since the internal braid angle is difficult to measure directly after the material is molded, it is typically measured in practical applications. This angle is defined as the angle between the surface yarn texture formed by adjacent unidirectional braided yarns on the specimen surface and the braiding direction z. For the microcellular configuration of three-dimensional five-dimensional and fully five-dimensional braided composite materials, the internal braiding angle is... With woven corner The relationship is: ; For a rectangular hexahedral in-cell configuration, the width ,thickness and height , respectively represented as: ; ; ; For cell configuration, width ,thickness , respectively represented as: ; ; ; In the formula, For internal braided corners, This is the axial section size factor. The short semi-axis when the cross-sectional shape of the braided yarn is elliptical; The factor representing the reduction ratio of the cross-sectional area of ​​the face cell; For surface weaving angles.

[0052] The proportions of inner cells, face cells, and corner cells in a three-dimensional braided composite material can be calculated using the following formula: In the formula, These represent the volume fractions of each region in the entire composite material structure, namely, the inner cell, the face cell, and the corner cell. This is the axial section size factor; and These represent the number of rows and columns of the main yarn being woven, respectively. This represents the fiber volume fraction. This indicates the volume fraction of fibers in the inner cells; This indicates the volume fraction of fibers in the face cells; This indicates the volume fraction of fibers in the cell.

[0053] V. Establishing a three-dimensional geometric model of a mesoscopic unit cell TexGen's solid modeling is based on the solid representation of yarn bundles in textile composites, mainly involving two key geometric features: (1) the cross-sectional shape of the yarn bundle; and (2) the spatial trajectory of the yarn. Therefore, in order to establish a unit cell three-dimensional geometric model of a three-dimensional braided composite material, several key geometric features need to be considered, including the main nodes of the yarn, the yarn trajectory, and the cross-sectional shape of the yarn. The trajectories of each yarn in each configuration have been obtained through the above analysis. The coordinates of the main nodes are defined using the XYZ() function. The coordinates of each main node of the three-dimensional five-directional braided composite material are shown in Tables 1 and 2. In TexGen, the default axial vector is defined as (0,0,1) and is used to calculate the direction of the yarn normal. If the direction of the yarn tangent is perpendicular or close to perpendicular, using the default Up vector will produce incorrect results, which will manifest as yarn distortion during rendering. To avoid this situation, the x-direction is used instead of the yarn weaving height direction.

[0054] Table 1. Coordinates of characteristic nodes of microcellular yarns in three-dimensional five-dimensional braided composite materials. Based on the assumptions established in this paper, in the inner cell, since the yarn trajectory is a straight line, it only needs to be defined through two principal nodes. However, in the face and corner cells, the yarn trajectory consists of multiple broken lines, so each broken line needs to be defined at its turning point.

[0055] Table 2. Coordinates of characteristic yarn nodes in the microstructure of three-dimensional five-dimensional braided composite materials. After determining the coordinates of each node, the yarn trajectory needs to be fitted. TexGen software provides several fitting methods, including linear interpolation fitting, Bezier curve fitting, and Cubic curve fitting. Linear interpolation is chosen to fit the yarn trajectory. The yarn resolution is defined using Set Resolution, which defines the fineness of generating a mesh, with a defined number of segments of 40. The yarn definition process is as follows: Figure 9 As shown.

[0056] TexGen provides three ways to assign cross-sectional shapes to yarns. The first method maintains a constant cross-section at all yarn locations. The second method assigns the cross-sectional shape and size at each node, which can be customized. The third method represents the cross-sectional position as a percentage of the yarn length, also allowing control over the shape and size at each location. This embodiment uses the method of assigning cross-sectional definitions to the braided yarn at feature points to establish a unit cell 3D geometric model. For the 3D braided composite material cell configuration, only the coordinates and cross-sectional information of four basic braided yarns and one axial yarn need to be defined. The addrepeat function is used to copy and translate the four basic braided yarns and axial yarn with different orientations. Then, defining the domain yields the desired 3D geometric model of the cell, such as... Figure 10 As shown. Similarly, Figure 11 It also clearly shows the yarn definition and yarn direction in the cell configuration. For the cell configuration, only the feature nodes and cross-sectional information of two external braiding yarns and one axial yarn need to be defined. The required three-dimensional geometric model of the cell can be obtained by repeating instructions and dividing the region. The difference between three-dimensional five-way braided composite material and full five-way braided composite material lies in the different repeated definitions of the axial yarn.

[0057] Through the above steps, based on the Texgen fabric modeling platform developed by the University of Nottingham, and using parametric modeling ideas and methods, to... Using the basic parameters as the primary input variables for parameterization, combined with yarn trajectory and coordinates, a Python program was written to create 3D geometric models of parametric mesoscopic internal and facial cells of 3D five-dimensional and all-five-dimensional braided composite materials in TexGen. For solid models under different braiding process conditions, only the basic variable parameters need to be changed in the parametric model to generate the required mesoscopic unit cell 3D geometric model. The parametric mesoscopic cell geometric models of 3D five-dimensional and all-five-dimensional braided composite materials are shown below. Figure 12 As shown in the figure. This method fully considers the geometric features of yarn nodes, trajectory, and cross-sectional shape, which helps to improve the accuracy and efficiency of modeling. It overcomes the difficulties in directly generating 3D braided material mesoscopic unit cells in TexGen software and the difficulties of traditional modeling platforms in modeling the real internal structure of braided composite materials, thus providing assistance for material selection and structural design of aero-engine bypass casings.

[0058] This embodiment provides a parametric modeling method for woven composite materials, characterized by the following workflow: analyzing the weaving process, analyzing yarn movement patterns, selecting and assuming modeling objects, analyzing unit cell geometric parameters, and establishing a three-dimensional geometric model of the mesoscopic unit cell. The focus is on the accurate description of the internal spatial yarn orientation of woven composite materials and the establishment of an adaptive mapping relationship between three-dimensional weaving process parameters (fiber bundle path, weaving angle, fiber volume fraction, etc.) and the TexGen geometric model through secondary development of the TexGen platform using Python. This achieves an integrated workflow of process parameter input, automatic modeling of the material's mesoscopic structure, and prediction of macroscopic mechanical properties. This method fully considers the geometric features of yarn nodes, trajectories, and cross-sectional shapes, which helps improve the accuracy and efficiency of modeling. It overcomes the difficulties in directly generating 3D braided material mesoscopic unit cells in TexGen software and the difficulties in modeling the real internal structure of braided composite materials by traditional modeling platforms. The accurate establishment of the internal structure of this type of composite material by the model can help understand and calculate the mechanical properties of this type of composite material. It solves the problem that the simplification of the internal structure of braided composite materials in traditional modeling platforms leads to inaccurate prediction of mechanical properties. It provides a high-precision and highly compatible digital development tool for the design and material selection of aero-engine bypass casings, structural design, and aero-engine composite component design.

[0059] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A parametric modeling method for woven composite materials, characterized in that, Includes the following steps: S1. Analyze the weaving process to determine the quantitative relationship between the weaving yarn and the axial yarn, as well as the motion law of the yarn carrier. S2. Analyze the movement patterns of yarns in the plane and in space to determine the spatial orientation of internal braided yarns, surface braided yarns, and axial yarns. S3. Based on the assumption of microstructure, intracellular configuration and cellular configuration are selected as modeling objects; S4, according to the weaving angle Axial section size factor Calculate the geometric structural parameters of the inner cell configuration and the face cell configuration; S5. Using the Python language interface provided by the TexGen open-source software, the fiber volume fraction... , woven corner Axial section size factor Using basic parameters as input variables for parameterization, combined with yarn trajectory and coordinates, a three-dimensional geometric model of the micro-unit cell of woven composite materials is established.

2. The parametric modeling method for woven composite materials according to claim 1, characterized in that, The weaving process is a three-dimensional five-directional weaving process or a three-dimensional full five-directional weaving process. The three-dimensional five-directional weaving process is an improvement on the four-step 1×1 weaving process, in which an axial yarn carrier is added between each row of yarn carriers. The three-dimensional full five-directional weaving process is in which an axially stationary yarn carrier is added between adjacent rows in the three-dimensional five-directional weaving process. The axially stationary yarn carrier remains stationary throughout the entire weaving process.

3. The parametric modeling method for woven composite materials according to claim 2, characterized in that, For three-dimensional five-directional weaving technology, the total number of weaving yarns Total number of axial yarns and total number of yarns satisfy: ； ； ； For three-dimensional five-directional weaving technology, the total number of weaving yarns Total number of axial yarns Total number of yarns that remain stationary along the axis and total number of yarns satisfy: ； ； ； ； In the formula, and These represent the number of rows and columns of the main yarn being woven, respectively.

4. The parametric modeling method for woven composite materials according to claim 2, characterized in that, The analysis of yarn movement patterns includes: the movement trajectory of the braided yarn carrier in the plane is zigzag; the axial yarn carrier only moves along the row direction and not along the column direction; the surface braided yarn carrier stops one step after reaching the surface from the inner region and then returns to the inner region. As the internally woven yarn undergoes each process step in space, it extends one-quarter of the knot height in the z-direction. After the tightening process, the yarn's trajectory in space is a straight line, located within two sets of orthogonal planes at ±45° to the cross-section of the woven prefabricated body. The angle between the yarn and the z-direction is the internal weaving angle. ; The spatial trajectory of the axial yarn is a straight line parallel to the z-axis and passes through the midpoint of the axial yarn carrier position point; The spatial trajectory of the surface-woven yarn is defined by two straight line segments, and the angle between these straight line segments and the axial direction of the yarn is defined as the surface weave angle. .

5. The parametric modeling method for woven composite materials according to claim 4, characterized in that, The internal braided corner With woven corner The relationship is: ； In the formula, the weaving angle Defined as the angle between the surface yarn texture formed by the arrangement of adjacent unidirectional braided yarns on the surface of the specimen and the braiding direction z.

6. The parametric modeling method for woven composite materials according to claim 1, characterized in that, The assumptions regarding the microstructure include: The braided yarns inside the unit cell extend in a straight line in space, taking into account the tightening during the braiding process and the compression of adjacent yarns. The cross-sectional shape of the braided yarn is elliptical. In TexGen, the cross-section is defined using the powerellipse function, with the power parameter P set to 0.5 to make the cross-section elliptical. The major and minor axes are respectively... and The relationship between the two is as follows: ,in: For internal braided corners; The axial yarn is a straight line parallel to the z-axis of space, with a square cross-section and the parallel sides of the cross-section forming ±45° with the cross-section of the precast body. The weaving process is stable, the mechanical properties of the yarn are not damaged, and the uniformity of the woven parts is maintained.

7. The parametric modeling method for woven composite materials according to claim 6, characterized in that, The geometric parameters of the inner cell configuration include width. ,thickness and height , respectively represented as: ； ； ； The geometric parameters of the cell configuration include width ,thickness , respectively represented as: ； ； ； In the formula, For internal braided corners, This is the axial section size factor. The short semi-axis when the cross-sectional shape of the braided yarn is elliptical; The factor representing the reduction ratio of the cross-sectional area of ​​the face cell; For surface weaving angles.

8. The parametric modeling method for woven composite materials according to claim 7, characterized in that, The proportions of inner cells, face cells, and corner cells in a three-dimensional braided composite material are calculated using the following formula: ； In the formula, These represent the volume fractions of each region in the entire composite material structure, namely, the inner cell, the face cell, and the corner cell. This is the axial section size factor; and These represent the number of rows and columns of the main yarn being woven, respectively. This represents the fiber volume fraction. This indicates the volume fraction of fibers in the inner cells; This indicates the volume fraction of fibers in the face cells; This indicates the volume fraction of fibers in the cell.

9. The parametric modeling method for woven composite materials according to claim 1, characterized in that, Establishing a three-dimensional geometric model of a mesoscopic unit cell includes: Use functions to define the coordinates of the characteristic nodes of the yarn; For the inner cell configuration, the yarn trajectory is a straight line, defined by two principal nodes; for the face cell configuration, the yarn trajectory consists of multiple broken lines, with nodes defined at the turning points of each broken line. The yarn trajectory was fitted using a linear interpolation method; Define the yarn segment resolution using Set Resolution, with 40 segment points; At the feature node, assign a cross-sectional shape and size to the braided yarn to define the yarn cross-section.

10. The parametric modeling method for woven composite materials according to claim 9, characterized in that, For the inner cell configuration, the coordinates and cross-sectional information of four basic braided yarns and one axial yarn are defined. The addrepeat instruction is used to copy and translate the four basic braided yarns and axial yarns with different orientations. Then, the segmentation domain is defined to obtain the three-dimensional geometric model of the inner cell. For the face cell configuration, the feature nodes and cross-sectional information of two outer braided yarns and one axial yarn are defined. The face cell three-dimensional geometric model is obtained through the repeat instruction and region segmentation.

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