A parameterized modeling method of woven composite rve considering yarn geometry variation
Patent Information
- Application Number
- CN202311348444.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-10-18
- Publication Date
- 2026-09-18
- Estimated Expiration
- 2043-10-18
AI Technical Summary
对于纱线路径来说，纬纱路径以直线假设居多，很少有考虑纬纱的弯扭效应，因此纱线的路径也有失真实
[0022] I. This invention proposes to use spline curves to smoothly fit the yarn path, allowing the yarn geometry to be adjusted by increasing or decreasing control points and changing the control point weights. This can closely match the direction of the real fabric, and there will be no penetration between different yarns.
Smart Images
Figure CN117350058B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of three-dimensional model reconstruction and relates to a modeling method for woven composite materials, and more particularly to a parametric modeling method for RVE of woven composite materials that considers yarn geometric changes. Background Technology
[0002] Compared to traditional metals, composite materials have become a crucial pillar in modern aerospace and other fields due to their superior mechanical properties and significantly reduced weight. Braided composite materials, with their numerous irreplaceable advantages, are known as third-generation fiber-reinforced composites. 2.5D braided ceramic matrix composites combine the advantages of two-dimensional and three-dimensional braiding, strengthening the bonds between layers. They possess both high in-plane strength and high interlaminar strength, and importantly, their manufacturing process is simple, leading to their widespread application.
[0003] However, the internal structure of braided composite materials is extremely complex, and the manufacturing process is lengthy, making it difficult for researchers to study the overall structure. They can only select representative volumetric elements (RVEs) as their research objects. Therefore, whether the established RVE model can accurately reflect the internal structure of the material directly affects the prediction of the mechanical properties of braided composite materials.
[0004] Currently, most RVE models are based on idealized assumptions. For yarn cross-sections, circular, elliptical, racetrack-shaped, and weighted curves are commonly used to describe the cross-sectional shape. However, in reality, the cross-sectional shapes of warp and weft yarns are not arbitrarily chosen and combined; rather, the cross-sectional changes caused by the compression of adjacent yarns should be considered. Regarding yarn paths, weft paths are mostly assumed to be straight, rarely considering the bending and twisting effects of the weft yarn, thus resulting in unrealistic yarn paths. Summary of the Invention
[0005] This invention provides a parametric modeling method for RVE of woven composite materials that takes into account yarn geometry changes, which can make the RVE model closer to the real fabric and overcome the shortcomings of the prior art.
[0006] To achieve the above objectives, this invention provides a parametric modeling method for RVE of woven composite materials considering yarn geometric variations, characterized by the following steps: Step 1, obtaining a slice image of the woven composite material; Step 2, obtaining the parameters of the weft and warp yarns based on the slice image of the woven composite material; Step 3, selecting basic yarn segments of the weft and warp yarns in the slice image of the woven composite material; selecting control points on the basic yarn segments of the weft and warp yarns respectively; obtaining the coordinates of each control point based on the parameters of the weft and warp yarns; Step 4, calculating the spline curve using the coordinates of the control points. The process involves several steps: 1) Using functions to fit the basic yarn segment path using multiple spline curve functions; 2) Dividing the fitted basic yarn segment into several cross-sections, each cross-section into several nodes, obtaining the coordinates of the nodes on each cross-section, and establishing a 3D model of the basic yarn segment; 3) Performing geometric transformations on the coordinates of each node of the basic yarn segment to generate the node coordinates of the complete yarn segment; 4) Shifting the complete yarn segment by a corresponding distance according to the number of layers to generate the complete RVE data point coordinates; 5) Realizing the complete RVE data point coordinates to complete the establishment of the RVE model.
[0007] Furthermore, the present invention provides a parametric modeling method for RVE of braided composite materials that takes into account the geometric changes of yarns, and may also have the following features: wherein, in step one, XCT technology is used to obtain a slice image of the braided composite material.
[0008] Furthermore, this invention provides a parametric modeling method for RVE of woven composite materials that considers yarn geometric variations, which may also have the following characteristics: In step two, the parameters obtained include: the number of weft yarn layers n, warp yarn spacing s1, weft yarn spacing s2, warp yarn thickness t1, weft yarn thickness t2, warp yarn width w1, weft yarn width w2, and warp yarn extrusion deformation ratio. Weft yarn extrusion texture ratio The method for obtaining the parameters is as follows: multiple measurements are taken at the same location on the woven composite material slice image, and the average value is obtained.
[0009] Furthermore, this invention provides a parametric modeling method for RVE of woven composite materials that considers yarn geometric changes, which may also have the following features: In step three, the basic yarn segment is the smallest repeatable unit; RVE can be regarded as a combination of several yarn segments, some of which can be used as basic yarn segments, and the rest can be obtained by performing operations such as translation, symmetry, and rotation on the basic yarn segments; the control points include at least two points on the center line of the basic yarn segment, two points on the lower thickness control curve, and two points on the upper thickness control curve.
[0010] Furthermore, this invention provides a parametric modeling method for RVE of woven composite materials that considers yarn geometric variations, which may also have the following feature: wherein, in step four, the spline curve function is:
[0011] s(x) = a + b(x - x0) + c(x - x0) 2 +d(x-x0) 3
[0012] In the formula, a, b, c, and d are all undetermined coefficients, which are calculated and determined based on the coordinates of the control points obtained in step three; the multiple spline curve functions include at least the spline curve function of the center line of the basic yarn segment, the spline curve function of the lower thickness control curve, and the spline curve function of the upper thickness control curve.
[0013] Furthermore, the present invention provides a parametric modeling method for RVE of woven composite materials that considers yarn geometric changes, and may also have the following features: in step four, the spline curve function shape is adjusted by adding control points and changing the control point weights based on the basic yarn segments, so as to fit the actual fabric orientation to the greatest extent.
[0014] Furthermore, this invention provides a parametric modeling method for RVE of woven composite materials that considers yarn geometric changes, which may also have the following features: In step five, the segmented cross-sections include a racetrack-shaped cross-section at the contact point of the warp and weft yarns, an elliptical cross-section at the non-contact point of the warp and weft yarns, and a cross-section between the racetrack-shaped cross-section and the elliptical cross-section; firstly, based on the slice diagram of the woven composite material and the parameters of the weft and warp yarns, the coordinates of each node on the racetrack-shaped cross-section and the elliptical cross-section are obtained; then, based on the coordinates of each node on the racetrack-shaped cross-section and the elliptical cross-section, according to the principle of "cross-section adaptation path", the coordinates of each node on the cross-section between the racetrack-shaped cross-section and the elliptical cross-section are calculated.
[0015] Furthermore, the present invention provides a parametric modeling method for RVE of braided composite materials that considers yarn geometric changes, which may also have the following features: in step five, when calculating the coordinates of each node on the cross section between the racetrack-shaped cross section and the elliptical cross section, a linear interpolation method is used to interpolate and fit the coordinates of the nodes with the same number on each cross section.
[0016] Furthermore, the present invention provides a parametric modeling method for RVE of braided composite materials that takes into account the geometric changes of yarn, and may also have the following feature: wherein, in step six, the geometric changes include translation, symmetry, and rotation.
[0017] Furthermore, the present invention provides a parametric modeling method for RVE of woven composite materials that considers yarn geometric changes, which may also have the following features: In step seven, the complete yarn segments of the weft yarn are copied and translated sequentially according to the layer direction by x1×(t1+t2); the complete yarn segments of the warp yarn are copied and translated sequentially according to the layer direction by x2×(t1+t2); x1 is the number of translations of the weft yarn, x1=0, 1~n; x2 is the number of translations of the warp yarn, x2=0, 1~n-1; n is the number of layers of the weft yarn, t1 is the warp yarn thickness, and t2 is the weft yarn thickness.
[0018] The present invention also provides a parametric modeling system for RVE of braided composite materials that takes into account yarn geometry variations, for executing the parametric modeling method for RVE of braided composite materials that takes into account yarn geometry variations.
[0019] The present invention also provides a computer-readable storage medium storing a computer program, characterized in that: when the computer program is run by a computer, it executes the described parametric modeling method for woven composite materials considering yarn geometric changes.
[0020] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: when the processor executes the computer program, it implements the aforementioned parametric modeling method for woven composite materials considering yarn geometric changes.
[0021] The beneficial effects of this invention are as follows:
[0022] I. This invention proposes to use spline curves to smoothly fit the yarn path, allowing the yarn geometry to be adjusted by increasing or decreasing control points and changing the control point weights. This can closely match the direction of the real fabric, and there will be no penetration between different yarns.
[0023] Second, this invention is a parametric modeling method. By simply changing the relevant parameters according to the algorithm, RVE models with different cross sections and paths can be obtained, which has strong applicability.
[0024] Third, the modeling method of the present invention is not limited to a certain weaving method in 2.5D, nor is it limited to a single dimension of 2.5D. It can be extended to RVE models with more dimensions and more weaving methods, and is applicable to the modeling of various composite materials, with wide versatility. Attached Figure Description
[0025] Figure 1 This is a flowchart of the RVE parameterized modeling method for braided composite materials that takes into account yarn geometric changes, as described in this invention;
[0026] Figure 2 This is a schematic diagram for selecting basic yarn segments and control points;
[0027] Figure 3 This is a comparison chart of yarn path fitting results;
[0028] Figure 4 These are yarn segments generated from cross-sections of different shapes;
[0029] Figure 5 It is the geometric transformation process from a basic warp segment to a complete warp segment;
[0030] Figure 6 It is an RVE model established using the method of this invention. Detailed Implementation
[0031] The present invention will be further described below with reference to specific embodiments.
[0032] like Figure 1 As shown, this embodiment provides a parametric modeling method for RVE of woven composite materials that considers yarn geometry variations. This method is used to model 2.5D one-to-three twill woven composite materials, including the following steps:
[0033] Step 1: Obtain a 2.5D one-to-three twill braided composite material slice image using XCT technology.
[0034] Step 2: Define the relevant parameters for establishing the RVE model, including: number of weft layers n, warp spacing s1, weft spacing s2, warp thickness t1, weft thickness t2, warp width w1, weft width w2, and warp compression deformation ratio. Weft yarn extrusion texture ratio Each parameter was obtained by taking multiple measurements at the same location in the slice image obtained in step one and averaging the results. The values of the basic modeling parameters are shown in the table below:
[0035] Table 1 Measurement parameters of 2.5D one-dimensional and three-dimensional twill woven composite materials
[0036]
[0037] Step 3: Observe the slice diagram and select the basic yarn segments of the weft and warp yarns. The basic yarn segment is the smallest repeatable unit, such as... Figure 2 As shown. Based on the basic yarn, relevant control points are selected. In this embodiment, nine control points are selected for both the warp and weft yarns. The coordinates of each control point are obtained based on the parameters of the weft and warp yarns. In this embodiment, the two-dimensional coordinates of the nine warp control points can be represented by the parameters in Table 1:
[0038] A, B, and C are points on the center line; A1, B1, and C1 are points on the lower warp thickness control curve; and A2, B2, and C2 are points on the upper warp thickness control curve. Using point A1 as the origin, the two-dimensional coordinates of these nine points can be represented according to the parameters in Table 1 as follows:
[0039] The coordinates of point A are: The coordinates of point B are: The coordinates of point C are The coordinates of point A1 are (0,0) and the coordinates of point B1 are... The coordinates of point C1 are: The coordinates of point A2 are (0, t1) and the coordinates of point B2 are... The coordinates of point C2 are:
[0040] The same applies to weft yarns.
[0041] Step 4: Calculate the spline curve function using the coordinates of the control points.
[0042] The spline curve function is:
[0043] s(x) = a + b(x - x0) + c(x - x0) 2 +d(x-x0) 3
[0044] In the formula, a, b, c, and d are all undetermined coefficients. By combining the coordinates of the control points mentioned above, the undetermined coefficients in the spline curve function are obtained, thus yielding the spline curve function.
[0045] The corresponding spline curve functions are obtained based on the control points of the centerline, lower thickness control curve, and upper thickness control curve.
[0046] By weighting the parametric spline curve function and adding control points, the shape of the function can be adjusted to conform to the direction of the real fabric.
[0047] The resulting multiple spline curve functions fit the basic yarn segment path, and the fitting results are as follows: Figure 3 As shown.
[0048] Step 5: Divide the yarn into several sections with a certain precision, and each section is further divided into several nodes. Select sections at key locations and determine their shapes. By observing the XCT slices, when the warp and weft yarns are in contact, the warp yarn has a racetrack-shaped cross-section; when they are not in contact, the warp yarn has an elliptical cross-section. Therefore, the divided sections are categorized as racetrack-shaped sections at warp and weft yarn contact points, elliptical cross-sections at warp and weft yarn non-contact points, and sections that fall between the racetrack-shaped and elliptical cross-sections.
[0049] First, based on the cross-sectional diagram of the woven composite material and the parameters of the weft and warp yarns, the coordinates of each node on the racetrack-shaped and elliptical cross-sections are obtained. Then, based on the coordinates of each node on the racetrack-shaped and elliptical cross-sections, and following the principle of "cross-section adaptation path," the coordinates of each node on the cross-section between the racetrack-shaped and elliptical cross-sections are calculated according to the path changes of the yarns. Linear interpolation can be used to fit the interpolation values of the nodes with the same number on each cross-section. That is, the cross-sectional shape is determined based on the XCT slices to determine the shape of key positions, and the cross-sectional shape between key positions is formed by interpolation fitting of the points with the same number on each cross-section.
[0050] Finally, the coordinates of the nodes on each cross section are obtained, and a basic three-dimensional model of the yarn segment is established, such as... Figure 4 As shown.
[0051] Step Six: Perform geometric transformations such as translation, symmetry, and rotation on the coordinates of each node of the basic yarn segment to generate the node coordinates of the complete yarn segment. For example... Figure 5 The diagram shows the process of generating a basic warp yarn segment into a complete warp yarn segment; the weft yarn follows the same principle.
[0052] Step 7: Based on the number of layers, shift the complete yarn segments by the corresponding distance. Specifically, copy and shift the complete weft yarn segments sequentially along the layer direction by x1×(t1+t2); copy and shift the complete warp yarn segments sequentially along the layer direction by x2×(t1+t2); where x1 is the number of shifts for the weft yarn, x1=0, 1~n; x2 is the number of shifts for the warp yarn, x2=0, 1~n-1; n is the number of weft yarn layers; t1 is the warp yarn thickness; and t2 is the weft yarn thickness. After the shift, complete RVE data point coordinates are generated.
[0053] Step 8: Import the data points into UG software for solidification, ultimately generating a model like... Figure 6 The RVE model of a 2.5D tri-twill woven composite material considering yarn geometry is shown.
[0054] The present invention also provides a parametric modeling system for RVE of braided composite materials that takes into account yarn geometry variations, for executing the parametric modeling method for RVE of braided composite materials that takes into account yarn geometry variations.
[0055] The present invention also provides a computer-readable storage medium storing a computer program, characterized in that: when the computer program is run by a computer, it executes the described parametric modeling method for woven composite materials considering yarn geometric changes.
[0056] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: when the processor executes the computer program, it implements the aforementioned parametric modeling method for woven composite materials considering yarn geometric changes.
[0057] In the embodiments disclosed in this application, a computer storage medium may be a tangible medium that may contain or store programs for use by or in conjunction with an instruction execution system, apparatus, or device. The computer storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of computer storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.
[0058] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed in this application can be implemented in electronic hardware or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.
[0059] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A parametric modeling method for RVE of braided composite materials considering yarn geometry variations, characterized in that: Includes the following steps: Step 1: Obtain cross-sectional images of the braided composite material using XCT technology; Step 2: Obtain the parameters of the weft and warp yarns based on the slice diagram of the woven composite material; The acquired parameters include: the number of layers n of weft yarns, the distance between warp yarns , the distance between weft yarns , the thickness of warp yarns , the thickness of weft yarns , the width of warp yarns , the width of weft yarns , the extrusion deformation ratio of warp yarns , and the extrusion deformation ratio of weft yarns ; the method for acquiring the parameters is: obtaining the average value by measuring and counting the same position of the woven composite material slice diagram for multiple times. Step 3: Select the basic yarn segments of the weft and warp yarns from the slice diagram of the woven composite material; Control points are selected on the basic yarn segments of the weft and warp yarns respectively; Based on the parameters of the weft and warp yarns, the coordinates of each control point are obtained; Step 4: Obtain the spline curve function using the coordinates of the control points; fit multiple spline curve functions to obtain the basic yarn segment path; Step 5: Divide the fitted basic yarn segment into several cross sections, and each cross section into several nodes. Obtain the coordinates of the nodes on each cross section and establish a three-dimensional model of the basic yarn segment. The segmented sections include a racetrack-shaped section at the contact point of the warp and weft yarns, an elliptical section at the non-contact point of the warp and weft yarns, and a section between the racetrack-shaped section and the elliptical section. First, based on the slicing diagram of the woven composite material and the parameters of the weft and warp yarns, the coordinates of each node on the racetrack-shaped section and the elliptical section are obtained. Then, based on the coordinates of each node on the racetrack-shaped section and the elliptical section, the coordinates of each node on the section between the racetrack-shaped section and the elliptical section are calculated according to the "section adaptation path" principle. When calculating the coordinates of each node on the section between the racetrack-shaped section and the elliptical section, linear interpolation is used to interpolate and fit the coordinates of the nodes with the same number on each section. Step 6: Perform geometric transformations on the coordinates of each node of the basic yarn segment to generate the node coordinates of the complete yarn segment; Step 7: Based on the number of layers, shift the complete yarn segment by the corresponding distance to generate complete RVE data point coordinates; Step 8: Solidify the coordinates of the complete RVE data points to complete the establishment of the RVE model.
2. The parametric modeling method for RVE of braided composite materials considering yarn geometry changes according to claim 1, characterized in that: in, In step three, the basic yarn segment is the smallest repeatable unit; The control points include at least two points on the center line of the basic yarn segment, two points on the lower thickness control curve, and two points on the upper thickness control curve.
3. The parametric modeling method for RVE of braided composite materials considering yarn geometry changes according to claim 1, characterized in that: in, In step four, the spline curve function is: In the formula, a, b, c, and d are all undetermined coefficients, which are calculated and determined based on the coordinates of the control points obtained in step three. Multiple spline curve functions include at least the spline curve function of the centerline of the basic yarn segment, the spline curve function of the lower thickness control curve, and the spline curve function of the upper thickness control curve.
4. The parametric modeling method for RVE of braided composite materials considering yarn geometry changes according to claim 1, characterized in that: in, In step four, the shape of the spline curve function is adjusted by adding control points and changing the weights of the control points, based on the basic yarn segments.
5. The parametric modeling method for RVE of braided composite materials considering yarn geometry changes according to claim 1, characterized in that: in, In step six, geometric transformations include translation, symmetry, and rotation.
6. The parametric modeling method for RVE of braided composite materials considering yarn geometry changes according to claim 1, characterized in that: in, In step seven, the complete yarn segments of the weft yarn are copied and translated sequentially according to the layer direction. ; Copy and translate the complete warp yarn segments sequentially according to the layer direction. ; x1 represents the number of times the weft yarn is translated, where x1 = 0, 1 to n; x2 represents the number of times the warp yarn is translated, where x2 = 0, 1 to n-1; n is the number of weft yarn layers. For warp thickness, This refers to the thickness of the weft yarn.