General knitting simulation method and system for special-shaped structural member based on model reconstruction algorithm

Abstract

The invention relates to the technical field of knitting processes, in particular to a general knitting simulation method and system for special-shaped structural parts based on a model reconstruction algorithm. The method comprises the following steps: acquiring three-dimensional model data of a core mold of the special-shaped structural part; through the three-dimensional model data, the center line of a core mold is extracted; according to the center line, the key section of the core mold is obtained; reconstructing a surface grid of the three-dimensional model of the core model by utilizing the key section; generating a yarn topology track based on kinematic characteristics by using the surface grid; and generating a fabric structure according to the yarn topology track. According to the method, through a model reconstruction algorithm and a kinematics method, redundant features of the complex special-shaped structural part core mold are effectively eliminated, and the precision and efficiency of weaving simulation are greatly improved; the error of the measurement result of the weaving experiment does not exceed 5 degrees, the actual production requirement is met, the method can be used for verifying the process design scheme in the actual production, and the high cost caused by sample piece trial-manufacture is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of weaving technology, and in particular to a general weaving simulation method and system for special-shaped structural parts based on a model reconstruction algorithm. Background Art

[0002] The 3D weaving process adjusts the weaving in real time according to the shape of the core mold, and realizes the synchronous weaving of large-scale yarns into an integral mesh preform, which is the preferred method for forming special-shaped structural parts. However, the complex features make it impossible to establish a high-precision fabric model, and it is difficult to simulate and verify the weaving process parameters and simulate the performance. Therefore, the high-precision simulation of the weaving process of special-shaped structural parts has become a current research hotspot.

[0003] In the prior art, the finite element method, geometric model analysis method and kinematic method are usually used to simulate the weaving process of special-shaped structural parts. Among them, the finite element method accurately simulates the behavior and response of the weaving process by performing multi-scale analysis on the weaving process of the yarn; the geometric model analysis method establishes a certain nonlinear equation set for the geometric function of the core mold shape and the position of the yarn, thereby simulating and analyzing the yarn landing point; the kinematic method provides detailed information on the weaving state in real time by performing kinematic analysis. However, the finite element method simulation takes a long time, the geometric model analysis method has low simulation accuracy for special-shaped structural parts, and the kinematic method has high requirements for the surface mesh of the core mold. Therefore, it is urgent to propose a fast, highly applicable, and universal weaving process simulation method for complex special-shaped structural parts.

[0004] At present, there is not much research on high-precision simulation methods for complex special-shaped structural parts, and there is no specific universal weaving simulation method for special-shaped structural parts based on model reconstruction algorithm. Summary of the invention

[0005] In view of the defects in the prior art, the present invention provides a universal weaving simulation method and system for special-shaped structural parts based on a model reconstruction algorithm.

[0006] In the first aspect, the present invention provides a general weaving simulation method for special-shaped structural parts based on a model reconstruction algorithm, comprising the following steps: obtaining three-dimensional model data of a core mold of a special-shaped structural part; extracting the center line of the core mold through the three-dimensional model data; obtaining the key section of the core mold according to the center line; reconstructing the surface mesh of the three-dimensional model of the core mold using the key section; generating a yarn topology trajectory based on kinematic characteristics using the surface mesh; generating a fabric structure according to the yarn topology trajectory. The present invention provides high-quality input for subsequent steps and ensures the accuracy of the simulation results by accurately obtaining the three-dimensional model data of the core mold of the special-shaped structural part; by extracting the center line and key section and reconstructing the surface mesh of the three-dimensional model accordingly, it realizes the accurate capture and expression of the complex morphology of the special-shaped structural part, and enhances the flexibility and adaptability of the simulation; the process of generating the fabric structure not only ensures the rationality and continuity of the yarn movement, but also provides strong technical support for the weaving of special-shaped structural parts.

[0007] Optionally, the extracting the center line of the core mold through the three-dimensional model data includes: constructing a center line space curve equation; substituting the three-dimensional model data into the center line space curve equation to obtain the trajectory of the center line. The center line space curve equation constructed by the present invention realizes the accurate description of the center line of the core mold, making the center line extraction process more scientific and rigorous; by substituting the three-dimensional model data into the center line space curve equation, the trajectory of the center line is directly calculated, which greatly improves the accuracy of the weaving simulation; the obtained center line trajectory has high accuracy, which provides reliable data support for the subsequent key section acquisition and surface mesh reconstruction.

[0008] Optionally, obtaining the key cross-section of the core mold according to the center line includes: obtaining the center line normal plane according to the trajectory of the center line; reconstructing the key cross-section of the core mold based on the intersection of the center line normal plane and the original mesh facet. The present invention accurately locates the cross-sectional shape of the core mold at different positions through the center line normal plane, ensuring the accuracy of key cross-sectional extraction; cross-sectional reconstruction is performed using the intersection of the center line normal plane and the original mesh facet, which not only retains the geometric features of the original mesh, but also achieves a detailed depiction of the complex shape of the core mold, thereby improving the accuracy of the simulation; the obtained key cross-section not only has good continuity, but also can truly reflect the structural characteristics of the core mold at different cross-sections, providing an important reference basis for subsequent surface mesh reconstruction and yarn topology trajectory generation.

[0009] Optionally, the reconstructing the key cross section of the core mold based on the intersection of the centerline normal plane and the original mesh patch includes: extracting the outermost contour points based on the intersection of the centerline normal plane and the original mesh patch to form an ordered contour point set; reconstructing the key cross section of the core mold according to the ordered contour point set. The present invention ensures that the outer contour morphology of the key cross section is consistent with the original mesh by extracting the outermost contour points, thereby improving the realism of the simulation; forming the extracted contour points into an ordered point set effectively avoids data confusion and reconstruction errors; reconstructing the cross section according to the ordered contour point set to generate a smooth and continuous key cross section, which not only retains the geometric features of the core mold, but also enhances the practicality and reliability of the simulation.

[0010] Optionally, the use of the key section to reconstruct the surface mesh of the core mold three-dimensional model includes: using the key section to obtain the number and position of the reconstructed patch corner points; reconstructing the surface mesh of the core mold three-dimensional model according to the number and position of the reconstructed patch corner points. The present invention accurately obtains the number and position of the reconstructed patch corner points through the key section, ensuring the accuracy and integrity of the surface mesh reconstruction, so that the reconstructed three-dimensional model truly reflects the geometric shape of the core mold; the mesh reconstruction is performed using the precise parameters of the reconstructed patch, effectively avoiding mesh distortion and topological errors, and improving the accuracy and realism of the three-dimensional model; the generated three-dimensional model surface mesh not only has good continuity, but also has high smoothness and detail expression, providing a reliable foundation for subsequent applications and analysis.

[0011] Optionally, the method of using the surface grid to generate a yarn topology trajectory based on kinematic characteristics includes: using the surface grid to judge the deposition state of the yarn based on the kinematic characteristics to obtain a judgment result; and generating a yarn topology trajectory based on the judgment result. The present invention accurately analyzes the dynamic behavior of the yarn during the weaving process by accurately judging the deposition state of the yarn, providing a basis for generating a real yarn trajectory; based on the judgment result of the yarn deposition state, the continuity and rationality of the yarn trajectory during the weaving process are ensured; the generated yarn topology trajectory not only meets the requirements of the weaving process, but also accurately reflects the distribution of the yarn on the surface of the three-dimensional model, providing a reliable basis for the subsequent generation of the fabric structure.

[0012] Optionally, generating a fabric structure according to the yarn topology trajectory includes: obtaining the interlacing form of the yarn using an interlacing relationship matrix according to the yarn topology trajectory; performing secondary processing on each interlacing point on the core mold surface based on the interlacing form to form the spatial topology of the yarn; and generating a fabric structure using an elliptical cross section and the spatial topology of the yarn. The present invention accurately captures the interlacing form of the yarn through an interlacing relationship matrix, ensuring the accuracy and authenticity of the fabric structure, so that the generated fabric structure can accurately reflect the relationship and arrangement between the yarns; secondary processing is performed on each interlacing point to form an accurate topological structure of the yarn in three-dimensional space, further enhancing the three-dimensional sense and detail expression of the fabric structure; the combination of an elliptical cross section and the yarn spatial topology not only simulates the actual form of the yarn, but also gives the fabric structure more flexibility and diversity, so that the generated fabric structure is more in line with the actual application requirements, and also provides a solid foundation for subsequent fabric simulation and analysis.

[0013] Optionally, the interweaving relationship matrix includes: an interweaving relationship matrix in which the same interweaving situation on the same yarn in the spindle arrangement of the diamond weaving structure has a period of 2 interweaving points; an interweaving relationship matrix in which the same interweaving situation on the same yarn in the spindle arrangement of the conventional weaving structure has a period of 4 interweaving points. The present invention achieves accurate capture and expression of the characteristics of the diamond weaving structure by defining an interweaving relationship matrix with an interweaving period of 2 interweaving points in the diamond weaving structure; by defining an interweaving relationship matrix with an interweaving period of 4 interweaving points in the conventional weaving structure, the stability and regularity of the fabric structure are ensured; through the two interweaving relationship matrices, not only the diversity of the fabric structure is enriched, but also flexible choices are provided for different weaving needs.

[0014] Optionally, the secondary processing includes: at the interweaving point where the matrix content is 1, the clockwise yarn is offset by twice the yarn thickness along the normal vector of the core mold surface, and the counterclockwise yarn is offset by once the yarn thickness; at the interweaving point where the matrix content is 0, the counterclockwise yarn is offset by twice the yarn thickness along the normal vector of the core mold surface, and the clockwise yarn is offset by once the yarn thickness. The present invention realizes the precise spatial positioning of the yarn at the interweaving point by performing yarn offset processing in different directions on the interweaving points with matrix contents of 1 and 0, avoiding overlap and conflict between yarns, and making the fabric structure clearer and more three-dimensional; for the different settings of the clockwise and counterclockwise yarn offsets, the kinematic characteristics and weaving laws of the yarn in the interweaving process are fully considered, ensuring the stability and uniformity of the fabric structure; through the secondary processing method, not only the simulation accuracy of the fabric structure is improved, but also more accurate data support is provided for subsequent fabric processing and manufacturing, which is helpful to improve the quality and performance of fabric products.

[0015] In the second aspect, the present invention provides a general weaving simulation system for special-shaped structural parts based on a model reconstruction algorithm, the system includes an input device, a processor, an output device and a memory, the input device, the processor, the output device and the memory are interconnected, wherein the memory is used to store a computer program, the computer program includes program instructions, the processor is configured to call the program instructions, and the system uses the general weaving simulation method for special-shaped structural parts based on the model reconstruction algorithm. The system provided by the present invention efficiently and accurately simulates the weaving process of special-shaped structural parts, greatly improves the efficiency and accuracy of design and production, and reduces the cost of trial and error; through the model reconstruction algorithm, the system flexibly responds to various complex shaped special-shaped structural parts, realizes the versatility and scalability of weaving simulation, and meets the needs of different industries and fields; the generated weaving simulation results have a high degree of realism and credibility, which provides strong data support for subsequent process optimization, product design and market analysis, and promotes the innovation and development of special-shaped structural parts weaving technology.

[0016] Compared with the prior art, the beneficial effects of the present invention include: through the model reconstruction algorithm, the redundant features of the core mold, such as through holes and bosses, are automatically identified and eliminated, thereby greatly improving the weaving simulation accuracy; through the kinematic method, the calculation time of the weaving simulation is reduced, thereby greatly improving the weaving simulation efficiency; based on the reconstructed grid and yarn trajectory, the interwoven spatial structure of the fabric is generated, realizing high-fidelity modeling and performance analysis of the fabric; the error between the simulation result and the weaving experimental measurement result does not exceed 5°, which meets the actual production requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a flow chart of a general weaving simulation method for special-shaped structural parts based on a model reconstruction algorithm according to an embodiment of the present invention; Figure 2 A schematic diagram of a core mold feature filtering process according to an embodiment of the present invention; Figure 3 A schematic diagram of a face patch combination method and its index number according to an embodiment of the present invention; Figure 4 A schematic diagram of a reconstructed core mold surface mesh according to an embodiment of the present invention; Figure 5 A schematic diagram of a weaving process according to an embodiment of the present invention; Figure 6 It is a schematic diagram of a knitting simulation after relative motion conversion according to an embodiment of the present invention; Figure 7 Schematic diagram of fabric structure under different spindle arrangements according to an embodiment of the present invention; Figure 8 Schematic diagram of the generation process of a single yarn entity unit according to an embodiment of the present invention; Fig. 9 A schematic diagram of the geometric dimensions of a core mold according to an embodiment of the present invention; Fig.10 Schematic diagram of the fabric spatial structure according to an embodiment of the present invention; Fig.11 A schematic diagram showing a comparison between simulated weaving and actual weaving of a fabric according to an embodiment of the present invention; Fig.12 A schematic diagram showing a comparison of braiding angles between simulated braiding and actual braiding in an embodiment of the present invention; Fig.13 It is a schematic diagram of the structure of a universal weaving simulation system for special-shaped structural parts based on a model reconstruction algorithm according to an embodiment of the present invention. DETAILED DESCRIPTION

[0018] The specific embodiments of the present invention will be described in detail below. It should be noted that the embodiments described herein are only for illustration and are not intended to limit the present invention. In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present invention. However, it is obvious to those of ordinary skill in the art that these specific details do not need to be adopted to implement the present invention. In other examples, in order to avoid confusing the present invention, known circuits, software or methods are not specifically described.

[0019] Throughout the specification, references to "one embodiment," "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment of the present invention. Therefore, the phrases "in one embodiment," "in an embodiment," "an example," or "an example" appearing in various places throughout the specification do not necessarily all refer to the same embodiment or example. In addition, particular features, structures, or characteristics may be combined in one or more embodiments or examples in any suitable combination and / or subcombination. In addition, it should be understood by those of ordinary skill in the art that the figures provided herein are for illustrative purposes and that the figures are not necessarily drawn to scale.

[0020] See also Figure 1 The embodiment of the present invention provides a general weaving simulation method for special-shaped structural parts based on a model reconstruction algorithm, and the method comprises the following steps: S1. Obtain the three-dimensional model data of the core mold of the special-shaped structural part.

[0021] In one embodiment, a 3D scanner is used to scan the core mold of the special-shaped structural part to obtain high-precision point cloud data.

[0022] Furthermore, the point cloud data is preprocessed to improve data quality; the preprocessing includes denoising and registration.

[0023] Furthermore, in the CAD software, a three-dimensional model is created using a modeling tool based on the point cloud data.

[0024] Furthermore, the 3D model is verified to check whether its size, shape and function meet the design requirements, and the model is optimized based on the verification results to ensure the accuracy and reliability of the model.

[0025] Furthermore, the optimized three-dimensional model data is exported for subsequent analysis.

[0026] S2. Extract the center line of the core mold through the three-dimensional model data.

[0027] Among them, S2 includes the following steps: S21. Construct the centerline space curve equation.

[0028] Optimizing the complex redundant features of the core model mesh, such as holes, flanges, concave corners, and hollows, is a necessary preprocessing process for finite element simulation, kinematics, and dynamics. Among them, the center line is the central reference for reconstructing the core model mesh, and its length interval corresponds to the length segment of the core model.

[0029] In one embodiment, based on the core mold end face coordinate system , The projection contour boundary of the plane is solved and synthesized, and the center line and traction trajectory are solved and synthesized. The modeling datum and posture of the mandrel 3D model are unified along the origin. Axis extension.

[0030] Specifically, the contour boundary of the mandrel is projected onto , On a plane, such as Figure 2 (A) As shown; Then, the curve of the contour boundary is fitted by the cubic curve interpolation algorithm and the curve fitting algorithm. The core shaft contour and the boundary curve are shown in Figure 2 (B) shown. Figure 2 (B1) and Figure 2 (B2) represents the algorithmic characteristics of the profile section, where Indicates the center line Points, Indicates the center line The tangent vector of the point, represents the center line normal plane, Represents the original mesh patch.

[0031] Furthermore, a point on the upper and lower boundary curves is taken and intersected along their respective normals. When the length of the line connecting the two points is equal, it is the discrete point of the center line.

[0032] Furthermore, according to the traction step value , and gives , The plane curve equation is as follows: , Furthermore, the plane curve equation is used to synthesize the center line space curve equation. In the synthesis process, the intersection point is solved by using the two-dimensional straight line point formula. , the two-dimensional straight line point formula is as follows: , in, The coordinates of , The coordinates of , The coordinates of , The coordinates of In this two-dimensional straight line point formula, when the line segment and line segments When the lengths are equal and the included angle is obtuse, On the center line, the corresponding point coordinates are marked as random discrete points of the center line The resulting centerline space curve equation is as follows: , in, Indicates The center line space curve trajectory corresponding to the pulling step length is is the pulling step length, is the maximum length of the center line, for The equation of a space curve in a plane, for Equation of a space curve in a plane.

[0033] S22. Substitute the three-dimensional model data into the centerline space curve equation to obtain the trajectory of the centerline.

[0034] In one embodiment, the three-dimensional model data obtained in step S1 is substituted into the centerline space curve equation to obtain the complete trajectory of the centerline.

[0035] S3. According to the center line, obtain the key cross section of the core mold.

[0036] Among them, S3 includes the following steps: S31. Obtain a centerline normal plane according to the trajectory of the centerline.

[0037] In one embodiment, a tangent vector of each point in the centerline trajectory is calculated, and the tangent vector is obtained by deriving a parametric equation of the centerline trajectory, or is approximately calculated by a vector difference between adjacent points.

[0038] Furthermore, for each point in the centerline trajectory, a plane passing through the point and having a normal vector perpendicular to the tangent vector is constructed, which is the normal plane of the centerline at the point.

[0039] S32. Based on the intersection of the centerline normal plane and the original mesh surface, obtain the key cross section of the core mold.

[0040] In one embodiment, first, using the center line normal plane and the original mesh patch The intersection of is taken as the dense section point set. Among them, the dense section point set of the center line normal plane and the original mesh patch satisfies the following equation: , in, , , is the coordinate of the point in the center line normal plane; , , is the normal vector coordinate in the center line normal plane, , is the ordinal number of the normal vector coordinate.

[0041] Furthermore, the outermost contour points are extracted to form an ordered contour point set, and redundant features such as holes, concave corners, and hollows are filtered out to form a key section of the reconstructed grid. The key section consists of two intersecting spatial straight lines. and Determine that the space straight line and The equations satisfied are as follows: , in, , , It is the ordinal number of the coordinates of the corner points of the triangle patch.

[0042] S4. Reconstruct the surface mesh of the core mold three-dimensional model using the key cross section.

[0043] Among them, S4 includes the following steps: S41. Using the key cross section, obtain the number and positions of the corner points of the reconstructed patch.

[0044] In one embodiment, the number of corner points is first determined using the key cross-section ordered contour point set.

[0045] Furthermore, the points with corresponding serial numbers in adjacent key sections are combined in sequence to form multiple sets of facet corner point sequences and normal lines, such as Figure 3 As shown. Among them, Figure 3 (A) is the correspondence diagram between the patch index number and the corner point sequence. A4.5 and A4.6 are the patch index numbers, and the black dots on the edge represent the corner points. Figure 3 (B) shows the patch index number A4.5 corresponding to the patch situation. Figure 3 In the figure, the A1.7 patch index is an odd number, and its corner point sequence is (P1.6, P1.5, P2.5) corresponding to Figure 3 (A); the A1.8 patch index number is an even number, and its corner point sequence is (P1.6, P2.5, P2.6) corresponding to (B) in Figure 3; the patches are distributed clockwise in each segment according to the index numbers A0.0, A0.1, A0.2...A1.0, A1.1, A1.2... It is assumed that each mesh segment (such as the patch set between S1-S2) has a total of 48 patches, and each key section has 24 patch corner points.

[0046] Furthermore, according to the ordered contour point set with index relationship, the coordinate position of the corner point on the triangle patch is obtained in the following form:

[0047] in, Represents the coordinates of the corner points on the triangle patch; is the corner point number, are the corner point coordinates.

[0048] S42. Reconstruct the surface mesh of the core mold three-dimensional model according to the number and positions of the corner points of the reconstructed surface patch.

[0049] In one embodiment, the positions of all patches in the space are determined according to the number and positions of the corner points of the reconstructed patches.

[0050] Furthermore, all the facets are combined together to reconstruct the surface mesh of the core mold 3D model, such as Figure 4 As shown in the figure, the surface topology is evenly distributed around the center line in a tangential direction, and the arrangement order corresponds to the patch index number. The adjacent patches can be directly called through the patch index number, which is the key to the rapid iteration method of process design. The reconstructed mesh removes the redundant features of the STL native mesh such as holes, corners, and hollows, and overcomes the disordered and uneven distribution of patches, but the adjacent patches cannot be directly called, resulting in a reduced iteration efficiency of the yarn trajectory prediction algorithm.

[0051] S5. Using the surface mesh, generate a yarn topology trajectory based on kinematic characteristics.

[0052] Among them, S5 includes the following steps: S51. Using the surface grid, based on the kinematic characteristics, the deposition state of the yarn is judged to obtain a judgment result.

[0053] See also Figure 5 In the process of weaving with a radial braiding machine, two sets of spindles carrying bobbins are placed in the corresponding notches on the dial, and the gear drives the dial, which drives the spindles to move clockwise and counterclockwise along the serpentine track on the chassis of the braiding machine, and the yarns are constantly intertwined to form a mesh structure. At the same time, the robot in the core mold attitude adjustment system clamps the core mold through the guide ring. Among them, the highly intertwined yarns cover the core mold surface on the forming plane after a convergence distance.

[0054] During the weaving process, large-scale yarns are simultaneously formed on the surface of the core mold. In order to simplify the weaving simulation and improve the computational efficiency, the present invention ignores the interaction between the yarns and the meandering motion of the spindles, and describes the guide ring as a The circular coil of the braiding device is described as having a radius of At the same time, in order to reduce the huge amount of calculation caused by updating the model data after each knitting posture change, after reading the surface mesh data of the reconstructed core model, the present invention sets the core model as a fixed reference system, and the spindle on the chassis performs a spiral motion according to the traction trajectory. Among them, the spiral line generated by the spiral motion satisfies the following expression: , in, for Time next The spatial position information of the spindles on the spiral line, the number of clockwise and counterclockwise spindles are both expressed as express; for The position information of the center point of the knitting machine chassis at all times; for The normal vector of the braiding machine chassis plane at the moment; is the core mold end face coordinate system The direction vector of the axis points to the inside of the core mold. for Time next The angular position information of each spindle on the chassis. Figure 6 As shown. Among them, Indicates clockwise yarn, Indicates counterclockwise yarn, , , Represents spatial coordinates.

[0055] In one embodiment, the deposition process of the yarn landing point on the core mold surface is mathematically described. When the yarn starts from the yarn outlet and passes through the guide ring, the yarn direction is forced to bend to form a convergence area and finally falls on the core mold surface. Due to the uneven distribution of yarns in the process of weaving non-circular core molds, the circumferential movement speed of the yarn on the guide ring is not equal to the weaving speed. Therefore. It is necessary to determine the intersection of the yarn and the guide ring based on the geometric relationship, and the expression is as follows: , in, for Time next The intersection of the yarn corresponding to each spindle and the guide ring, for Time next The projection point position information of the yarn drop point corresponding to each spindle on the plane where the guide ring is located, for Time next The projection point position information of each spindle on the plane where the guide ring is located, Describes the yarn drop point in the guide ring coordinate system Projection of the plane, The yarn drop point position and spindle position in the guide ring coordinate system are described in the guide ring coordinate system. Projection of the plane, is the guide ring coordinate system The angle formed by the contact point in the plane, the midpoint of the guide ring and the landing point is expressed as follows: , in, for The location of the weaving track at all times.

[0056] Furthermore, the deposition state of each yarn is judged according to the intersection of the yarn and the guide ring. , Yarn drop point and the normal vector of the triangular mesh on the surface of the core mold where the landing point is located , the yarn state is judged and analyzed. When the yarn is located under the triangular grid, the yarn is defined to be deposited on the surface of the core mold to form a fabric. The conditional expression for forming a fabric is as follows: , S52. Based on the judgment result, generate a yarn topology trajectory.

[0057] In one embodiment, based on the judgment result of the deposition state of each yarn, a yarn topological trajectory formed by the yarn deposited on the surface of the core mold is generated.

[0058] S6. Generate a fabric structure according to the yarn topology trajectory.

[0059] Wherein, S6 further comprises the following steps: S61. According to the yarn topological trajectory, using the interweaving relationship matrix, the interweaving form of the yarn is obtained.

[0060] In order to achieve high-precision modeling and performance analysis of the subsequent composite materials, it is necessary to establish an interwoven structure in which the fabric covers the outside of the core mold. There are two main types of interwoven structures, namely diamond weaving structure and conventional weaving structure. The weaving structure is closely related to the arrangement of the spindles. The relationship between the two fabric structures and the spindle arrangement is shown in Figure 7. Figure 7 (a) shows the relationship between the diamond weaving structure and the spindle arrangement. Figure 7 (b) Represents the relationship between conventional weaving structure and spindle arrangement.

[0061] In the spindle arrangement of the diamond braided structure, the interweaving of the clockwise spindle and the counterclockwise spindle is single and has strong periodicity. Since the same interweaving situation on the same yarn occurs at two interweaving points in a period, it can be seen from the movement of the dial that the interweaving points formed by the clockwise spindle and the counterclockwise spindle of different parity sequences are one form of interweaving points, which is defined as the clockwise yarn on the top and the counterclockwise yarn on the bottom in the present invention. On the contrary, the interweaving points formed by the clockwise spindle and the counterclockwise spindle of the same parity sequence are another form, which is defined as the clockwise yarn on the bottom and the counterclockwise yarn on the top in the present invention.

[0062] In one embodiment, for the convenience of calculation, the spatial position of the interleaving point is described in matrix form, and the interleaving relationship is defined as The interweaving relationship matrix of the clockwise yarn on the top and the counterclockwise yarn on the bottom is defined as 1 in the interweaving relationship matrix, and the interweaving state of the clockwise yarn on the bottom and the counterclockwise yarn on the top is defined as 0 in the interweaving relationship matrix. The interweaving relationship matrix in the spindle arrangement of the diamond braided structure The expression is as follows: , In the spindle arrangement of the conventional weaving structure, the interweaving pattern of the clockwise spindle and the counterclockwise spindle is more complicated than that of the diamond weaving structure, and the cycle of the same interweaving situation on the same yarn is 4. Therefore, it is necessary to discuss the four spindles with different serial numbers. The interweaving form under conventional weaving is two up and two down. Therefore, according to the spindle arrangement order, the interweaving relationship matrix under conventional weaving is The expression is:

[0063] Furthermore, based on the above interweaving relationship matrix, the interweaving morphology of the yarn is preliminarily generated.

[0064] S62. Based on the interweaving morphology, each interweaving point on the surface of the core mold is subjected to secondary processing to form the spatial topology of the yarn.

[0065] In one embodiment, based on the interlacing morphology, each interlacing point on the core mold surface is subjected to secondary processing to form the spatial topology of the yarn. The secondary processing includes: At the interlacing point where the matrix content is 1, the normal vector of the clockwise yarn along the surface of the mandrel is offset by twice the yarn thickness, and the counterclockwise yarn is offset by once the yarn thickness; At the interlacing point where the matrix content is 0, the normal vector of the counterclockwise yarn along the surface of the core mold is offset by twice the yarn thickness, and the normal vector of the clockwise yarn is offset by once the yarn thickness.

[0066] S63. Generate a fabric structure using the elliptical cross-section and the spatial topology of the yarn.

[0067] In one embodiment, the solid element of a single yarn is generated using the elliptical cross-section and the spatial topology of the yarn, such as Figure 8 shown. Figure 8 The generation process of the fabric spatial structure is demonstrated.

[0068] For the weaving simulation method of the present invention, in one embodiment, a simulation experiment was carried out using Matlab R2023b software, and the calculation was performed on a computer equipped with an Intel(R) Core(TM) i9-14900HX processor, an NVIDIA GeForce RTX4070 graphics card, 32GB of RAM and Windows 11 operating system. In the actual weaving process, the yarn is tied tightly with a binding tape at the starting section of the core mold. Therefore, the starting points of the yarn are evenly distributed on the end face of the core mold, and the initial landing point of the yarn in the simulation model is the intersection of the line connecting the midpoints of the spindle and the end face of the core mold and the contour line. Among them, the geometric dimensions of the core mold are as follows: Fig. 9 Through this experiment, the generated fabric spatial structure is shown as Fig.10 shown.

[0069] In the weaving experiment, a 176-spindle radial braiding machine made of Yunlu Composites and a KUKA six-degree-of-freedom industrial robot KR 240 R2700-prime installed on a linear guide rail were used. Each spindle in the radial braiding machine moves forward along the track of the braiding machine chassis, and the yarn is carried by the yarn tube installed on the spindle for weaving. At the same time, the motion system of the braiding machine consists of 4 servo motors, 2 vibration motors and their controllers. The parameters of the braiding equipment are shown in Table 1.

[0070]

[0071] from Fig.11It can be seen that the reconstruction grid algorithm and weaving simulation method proposed in the present invention can accurately simulate the weaving process under any weaving process parameters, and the fabric structure has good consistency with the actual weaving structure. The weaving angles of simulated weaving and actual weaving are compared, as shown in Figure 2. Fig.12 As shown in the figure, due to the influence of the initial convergence distance, the braiding angle changes with a certain delay in the initial stage. Fig.12 It can be seen that the distribution of the fabric in the initial section of the core mold is more complex, and the braiding angle shows a trend of first decreasing, then increasing, and finally becoming relatively stable. As the cross-sectional shape of the core mold changes from a circular cross-section to a quasi-rectangular cross-section, the error of the braiding angle in the simulated braiding and actual braiding processes gradually increases. In the circular cross-sectional part, since the yarn and the core mold are tangent in the time series, the influence of the force between the yarns on the braiding angle prediction results is not considered. However, in the actual weaving process on the quasi-rectangular cross-section, due to the interaction between the yarns, there is a phenomenon of premature deposition of the fabric, so there is a prediction error. According to the measurement results, the error can be guaranteed to be within 5°, so it meets the actual working conditions.

[0072] See also Fig.13 , Fig.13 The schematic diagram of the structure of the general braiding simulation system for special-shaped structural parts based on the model reconstruction algorithm in the embodiment of the present invention is shown. The system includes an input device, a processor, an output device and a memory, wherein the input device, the processor, the output device and the memory are interconnected, wherein the memory is used to store a computer program, the computer program includes program instructions, the processor is configured to call the program instructions, and the system uses the general braiding simulation method for special-shaped structural parts based on the model reconstruction algorithm.

[0073] In this embodiment, the input device is mainly used to input knitting data information, which includes knitting process parameters, shape and size information of special-shaped structural parts, and type of knitting materials. Through the input device, not only can the required knitting process parameters and related information of special-shaped structural parts be conveniently input, but also instructions can be sent to the system, such as starting knitting simulation and adjusting process parameters.

[0074] The processor is the core part of the system, including various types of computing units, such as a central processing unit and a graphics processing unit, to support complex computing tasks; the processor is mainly used to execute the model reconstruction algorithm, process the input knitting data information, and generate corresponding knitting simulation results; The output device uses a display screen to display the results processed by the processor to the user. The results include images of knitting simulation and detailed data during the knitting process.

[0075] The memory adopts a high-speed solid-state hard disk, which has the characteristics of fast reading and writing speed, large capacity and high reliability, can meet the needs of large data storage, and is used to store the knitting data information input by the input device and the results processed by the processor.

[0076] In summary, the present invention proposes a novel weaving process simulation method based on a model reconstruction algorithm for any shape of special-shaped structural parts. Among them, the model reconstruction algorithm can automatically identify and eliminate the redundant features of the through holes and bosses of the core mold that affect the prediction accuracy of the fabric, thereby ensuring the accuracy and efficiency of the weaving simulation. At the same time, based on the reconstructed grid and yarn trajectory, the interwoven spatial structure of the fabric is generated, which is convenient for high-fidelity modeling and performance analysis of the fabric. Based on the kinematic characteristics, the present invention greatly improves the calculation speed while ensuring accuracy, and the calculation time for special-shaped structural parts is much less than the calculation time of commercial finite element software. Experimental verification was carried out through the aircraft air inlet, and the error between the braiding angle extracted in the circular cross-section part and the measured value was extremely small. In the variable cross-section part, since the present invention does not consider the interaction relationship between the yarns, the error value is significantly increased, but it can still be guaranteed to be within 5°. Therefore, the present invention meets the actual production accuracy, can be used to verify the process design scheme in actual production, and reduce the high cost brought by the trial production of samples.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A general braiding simulation method for special-shaped structural parts based on a model reconstruction algorithm, characterized in that: The method comprises the following steps: Obtain 3D model data of the core mold of special-shaped structural parts; Extracting the center line of the core mold through the three-dimensional model data; According to the center line, a key cross section of the core mold is obtained; Reconstructing the surface mesh of the three-dimensional model of the core mold by using the key cross section; Using the surface mesh, based on kinematic characteristics, a yarn topology trajectory is generated; A fabric structure is generated according to the yarn topology trajectory.

2. A general braiding simulation method for special-shaped structural parts based on a model reconstruction algorithm according to claim 1, characterized in that: The extracting the center line of the core mold through the three-dimensional model data includes: Construct the centerline space curve equation; Substitute the three-dimensional model data into the centerline space curve equation to obtain the centerline trajectory.

3. A general braiding simulation method for special-shaped structural parts based on a model reconstruction algorithm according to claim 1, characterized in that: The key cross-section of the core mold obtained according to the center line includes: According to the trajectory of the center line, the center line normal plane is obtained; Based on the intersection of the centerline normal plane and the original mesh surface, the key cross section of the core mold is reconstructed.

4. The general braiding simulation method for special-shaped structural parts based on model reconstruction algorithm according to claim 1 is characterized in that: The key cross-section of the reconstructed core mold based on the intersection of the center line normal plane and the original mesh patch includes: Based on the intersection of the center line normal plane and the original mesh patch, the outermost contour points are extracted to form an ordered contour point set; The key cross section of the core mold is reconstructed according to the ordered contour point set.

5. The general braiding simulation method for special-shaped structural parts based on model reconstruction algorithm according to claim 1 is characterized in that: The method of reconstructing the surface mesh of the core mold three-dimensional model by using the key cross section includes: Using the key cross section, obtaining the number and positions of the reconstructed patch corner points; The surface mesh of the core mold three-dimensional model is reconstructed according to the number and positions of the reconstructed surface patch corner points.

6. The general braiding simulation method for special-shaped structural parts based on model reconstruction algorithm according to claim 1 is characterized in that: The generating of the yarn topology trajectory based on the kinematic characteristics by using the surface mesh comprises: Using the surface grid, based on the kinematic characteristics, the deposition state of the yarn is judged to obtain a judgment result; Based on the judgment result, a yarn topology trajectory is generated.

7. The general braiding simulation method for special-shaped structural parts based on model reconstruction algorithm according to claim 1 is characterized in that: Generating a fabric structure according to the yarn topology trajectory comprises: According to the yarn topological trajectory, using the interweaving relationship matrix, obtaining the interweaving form of the yarn; Based on the interlacing morphology, each interlacing point on the surface of the core mold is subjected to secondary processing to form a spatial topology of the yarn; The elliptical cross-section and the spatial topology of the yarn are used to generate a fabric structure.

8. A general braiding simulation method for special-shaped structural parts based on a model reconstruction algorithm according to claim 7, characterized in that: The interweaving relationship matrix includes: The interweaving relationship matrix of the same interweaving situation on the same yarn in the spindle arrangement of the diamond braiding structure has a period of 2 interweaving points; The period of the same interweaving situation on the same yarn in the spindle arrangement of the conventional weaving structure is an interweaving relationship matrix of 4 interweaving points.

9. A general braiding simulation method for special-shaped structural parts based on a model reconstruction algorithm according to claim 7, characterized in that: The secondary processing includes: At the interlacing point where the matrix content is 1, the normal vector of the clockwise yarn along the surface of the mandrel is offset by twice the yarn thickness, and the counterclockwise yarn is offset by once the yarn thickness; At the interlacing point where the matrix content is 0, the normal vector of the counterclockwise yarn along the surface of the core mold is offset by twice the yarn thickness, and the normal vector of the clockwise yarn is offset by once the yarn thickness.

10. A general braiding simulation system for special-shaped structural parts based on a model reconstruction algorithm, the system using the general braiding simulation method for special-shaped structural parts based on a model reconstruction algorithm according to any one of claims 1 to 9, characterized in that: The system includes an input device, a processor, an output device and a memory, wherein the input device, the processor, the output device and the memory are connected to each other, wherein the memory is used to store a computer program, the computer program includes program instructions, and the processor is configured to call the program instructions.

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