A composite material fiber direction simulation modeling method and system

Abstract

The application relates to the technical field of fiber direction simulation, in particular to a composite material fiber direction simulation modeling method and system. The method comprises the following steps: collecting a fiber laying track, correcting the bending radius and unit tangent direction of a path point, and obtaining a fiber laying corrected track; constructing a first direction distribution map according to the tangent direction of each path point in the fiber laying corrected track; analyzing the coverage range of each path in the first direction distribution map on a component curved surface, identifying a curved surface overlapping and crossing area, and calculating an included angle adjustment amount of a direction vector; dividing the first direction distribution map into finite volume units, so as to obtain a second direction distribution map; and performing fiber direction simulation verification according to the second direction distribution map and in combination with preset material anisotropy properties, so as to obtain a fiber direction simulation result. The application is helpful to improve the spatial accuracy of fiber direction modeling and the consistency of simulation prediction.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fiber direction simulation, and particularly relates to a composite material fiber direction simulation modeling method and system. BACKGROUND

[0002] Composite materials have been widely used in aerospace, automobile, rail transportation and high-end manufacturing fields due to their light weight, high strength, corrosion resistance and other characteristics. The laying direction of the internal fibers of the composite material directly determines the mechanical properties of the structural parts under different load conditions.

[0003] In the prior art, composite material fiber direction modeling usually relies on idealized ply description in CAD or CAE systems, and a finite element model is established by simplifying to a two-dimensional ply angle or a regional average direction vector. However, such a method is difficult to cover the three-dimensional fiber deviation caused by interlayer slip or local thickening in the multi-layer overlapping area, thereby lacking accurate characterization of the three-dimensional fiber direction under the real forming path. SUMMARY

[0004] Therefore, it is necessary to provide a composite material fiber direction simulation modeling method and system to solve at least one of the above technical problems.

[0005] To achieve the above-mentioned purpose, a composite material fiber direction simulation modeling method comprises the following steps:

[0006] Step S1: acquiring a fiber laying track through a process control interface connected with an automatic fiber laying device; correcting a bending radius and a unit tangent direction of a path point according to a fitting error of the fiber laying track on a component surface to obtain a fiber laying corrected track;

[0007] Step S2: mapping a tangent direction of each path point in the fiber laying corrected track to a tangent base of a preset forming component CAD model surface to construct a first direction distribution map;

[0008] Step S3: analyzing a coverage range of each path in the first direction distribution map on the component surface, identifying a surface overlapping and crossing area, calculating a fiber disturbance deviation amplitude of each layer in the normal direction of the surface overlapping and crossing area, and calculating an included angle adjustment amount of a direction vector according to the fiber disturbance deviation amplitude and a path crossing angle of the surface overlapping and crossing area;

[0009] Step S4: dividing the first direction distribution map into finite volume elements, using the included angle adjustment amount of the direction vector to represent a spatial distribution trend of a fiber main direction vector and a fiber secondary direction vector of the corresponding finite volume element, and obtaining a second direction distribution map;

[0010] Step S5: taking the fiber main direction vector of the second direction distribution map as the principal axis direction and the fiber secondary direction vector as the transverse reference direction orthogonal to the principal axis, and performing fiber direction simulation verification in combination with the preset material anisotropic properties, to obtain a fiber direction simulation result.

[0011] The application collects the real fiber laying track through the interface with the automatic fiber laying equipment, corrects the path error in combination with the component CAD surface, establishes the corresponding relationship between the actual laying direction and the surface, further constructs the first direction distribution map on the component surface, identifies the disturbance caused by the interlayer cross in the overlapping area, calculates the adjustment amount of the path angle, maps the direction data into the continuously divided finite volume unit based on the adjustment amount, extracts the main direction and the secondary direction by using the statistical characteristics of the direction vector, forms the second direction distribution map of the fiber spatial distribution, maps the second direction into the anisotropic properties of the material, performs simulation analysis and comparison with the expected performance, and iteratively adjusts the angle adjustment amount through the disturbance sensitivity coefficient if the deviation exceeds the threshold, optimizes the simulation precision, and finally realizes the integrated feedback closed loop of the spatial distribution modeling and performance simulation of the real fiber direction in the composite component. The three-dimensional fiber deviation problems such as interlayer overlapping sliding and local thickening that cannot be accurately reflected by the two-dimensional idealized layer modeling in the prior art are effectively solved. Through the construction of the angle adjustment amount and the disturbance feedback mechanism, the closed loop optimization of the fiber direction modeling and the material anisotropic performance simulation is realized, the spatial accuracy of the fiber direction modeling in the composite component is significantly improved, and the consistency of the simulation prediction is improved. It is suitable for high-precision engineering structure design and performance evaluation.

[0012] Optionally, the application provides a composite fiber direction simulation modeling system for performing the composite fiber direction simulation modeling method as described above, which comprises:

[0013] A track acquisition module is configured to acquire the fiber laying track through a process control interface connected with the automatic fiber laying equipment, correct the bending radius and the unit tangent direction of the path point according to the fitting error of the fiber laying track on the component surface, and obtain the fiber laying corrected track.

[0014] A tangent direction mapping module is configured to map the tangent direction of each path point in the fiber laying corrected track into the tangent base of the preset formed component CAD model surface, to construct the first direction distribution map.

[0015] An angle adjustment amount calculation module is configured to analyze the coverage range of each path in the first direction distribution map on the component surface, identify the surface overlapping and crossing area, calculate the fiber disturbance offset amplitude in the normal direction of each layer in the surface overlapping and crossing area, and calculate the angle adjustment amount of the direction vector according to the fiber disturbance offset amplitude and the path crossing angle of the surface overlapping and crossing area.

[0016] The main and secondary direction division module is configured to divide the first direction distribution map into finite volume units, and to use the included angle adjustment amount of the direction vector to represent the spatial distribution trend of the fiber main direction vector and the fiber secondary direction vector for the corresponding finite volume unit, so as to obtain a second direction distribution map.

[0017] The simulation module is configured to use the fiber main direction vector of the second direction distribution map as a main shaft direction, the fiber secondary direction vector as a transverse reference direction orthogonal to the main shaft, and to perform fiber direction simulation verification in combination with preset material anisotropic properties, so as to obtain a fiber direction simulation result.

[0018] The composite material fiber direction simulation modeling system of the present application can realize any one of the composite material fiber direction simulation modeling methods of the present application, and is used as a medium for joint operation and signal transmission between modules to complete the composite material fiber direction simulation modeling method. The modules in the system cooperate with each other, thereby improving the spatial accuracy of fiber direction modeling and the consistency of simulation prediction in the composite material component. BRIEF DESCRIPTION OF DRAWINGS

[0019] Other features, objects and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments, made with reference to the following drawings:

[0020] Fig. 1 The figure is a schematic diagram of the steps of the composite material fiber direction simulation modeling method of the present application.

[0021] Fig. 2 The figure is a schematic diagram of the first direction distribution map in the embodiment of the present application.

[0022] The implementation of the object of the present application, functional features and advantages will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0023] The technical method of the present application will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0024] In addition, the accompanying drawings are included to provide a further understanding of the application, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the application and, together with the description, serve to explain the principles of the application. In the drawings:

[0025] It should be understood that, although terms such as "first", "second", and the like can be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element without departing from the scope of the example embodiments. The term "and / or" as used herein encompasses any and all combinations of one or more of the associated associated items.

[0026] To achieve the above object, there is provided Figs. 1-2 The present application provides a composite material fiber direction simulation modeling method, the method comprising the following steps:

[0027] Step S1: collecting the fiber laying track through the process control interface connected with the automatic fiber laying device; correcting the bending radius and unit tangent direction of the path point according to the fitting error of the fiber laying track on the component surface to obtain the fiber laying correction track;

[0028] In one embodiment of the present invention, fiber placement trajectory data during the molding process of composite material components is acquired in real time through a process control interface connected to an automated fiber placement device. This data is recorded in the form of a path point sequence, with each point containing three-dimensional coordinates (X, Y, Z), placement speed, and tangential direction vector. The acquired path point coordinates are projected onto the CAD model of the molded component, and the corresponding position of the path point in the component's surface coordinate system is obtained using a local surface parametric method (such as NURBS or Bezier surface UV coordinates). The surface normal vector at this position is calculated and vector difference is performed with the tangent vector of the path point to extract the offset components of the tangential and normal directions. Error thresholds for tangential and normal offsets are set (e.g., 0.2 mm and 0.1 rad), and continuous segments of path points with errors exceeding the thresholds are identified as path segments to be corrected. Curvature continuity analysis is performed on the path segment to be corrected and its adjacent path points, and curve fitting is performed using cubic B-splines to maintain the continuity of the first derivative of adjacent segments, ensuring a smooth transition of the fiber placement trajectory and avoiding abrupt changes. Based on the positional variation relationship of continuous points in the fitted path segment, the tangent direction vector is calculated using the central difference method, and the new direction vector of the path point is obtained by normalization, thus forming the fiber laying correction trajectory.

[0029] Step S2: Map the tangent direction of each path point in the fiber placement correction trajectory to the tangent base of the preset CAD model surface of the molding component to construct the first direction distribution map;

[0030] In one embodiment of the present invention, coordinate difference is performed on adjacent path points in the fiber placement correction trajectory, using... Calculate the unit tangent vector for each path point. The first in the fiber placement correction trajectory Spatial coordinate vectors of path points. For the first The unit tangent direction vector at each path point represents the instantaneous direction of fiber placement. , respectively path points The coordinates of two adjacent path points are used to calculate the central difference. For each path point, its U and V parameter positions are extracted from the CAD model, and the orthogonal tangent basis (i.e., the tangent vectors in the U and V directions) of the local surface are obtained using CAD kernel functions, denoted as... . The tangent vector of each path point Project to Calculate the directional projection of the local base in the surface coordinate system. This refers to the fiber placement direction on the component surface. These are the weighting coefficients for projecting the tangential directions of path points onto the U / V direction basis of the surface. By performing position matching and interpolation fitting (such as Gaussian weighted interpolation) on the direction projections of all path points, a first direction distribution map covering the entire component surface is generated. This distribution map can be represented as a direction vector field on the component surface mesh.

[0031] Step S3: Analyze the coverage of each path on the component surface in the first direction distribution map, identify the overlapping and intersecting areas of the surfaces; calculate the fiber disturbance offset amplitude in the normal direction of each layer in the overlapping and intersecting areas of the surfaces, and calculate the angle adjustment of the direction vector based on the fiber disturbance offset amplitude and the path intersection angle of the overlapping and intersecting areas of the surfaces.

[0032] In this embodiment, the tangent vectors of all path points are extracted from the first direction distribution map. The bandwidth values ​​in each extension direction on both sides (e.g., ±3mm), construct a rectangular projection strip corresponding to each path point (center at the path point coordinates, direction is...). Width is (The length is determined by the point spacing). Perform spatial intersection operations (such as AABB box detection) on the rectangular projections of all path points to identify areas where paths intersect or overlap, forming path intersection candidate areas. Based on the laying order, identify path pairs with a "first-laid-last-laid" relationship within the intersection areas. Calculate their center-to-center spacing in the normal direction of the component surface. And calculate the angle between the two path direction vectors. If satisfied (e.g., 0.8mm) and If the angle is 20°, then the candidate intersection area is considered an effective surface overlap intersection region. Extract the set of path points in these regions, calculate their center height in the normal direction, and calculate the relative height difference layer by layer according to the laying order. Combined with the path curvature sign, determine whether the upper-layer path is shifted upwards or downwards, thus obtaining the fiber perturbation offset amplitude. Calculate the angle of the path direction Based on the normalized value of the disturbance offset Combined with the disturbance sensitivity coefficient The direction adjustment amount is obtained. .in This represents the fiber disturbance offset amplitude.

[0033] Step S4: Divide the first directional distribution map into finite volume units, and use the angle adjustment of the directional vectors to characterize the spatial distribution trend of the fiber principal directional vector and the fiber secondary directional vector in the corresponding finite volume units to obtain the second directional distribution map;

[0034] In this embodiment, according to the path point density distribution on the surface of the component, the number of path points of each local area is calculated using a sliding window. A density threshold (such as ≥5 path points per square centimeter) is set, and the area that meets the condition is extracted as the effective path distribution area. The maximum vertical spacing (such as the maximum interlayer spacing 2mm) of the path points in the normal direction is counted in the effective area, and is set as the vertical division spacing of the volume unit. Isometric slicing is performed in the normal direction of the component curved surface to obtain a three-dimensional finite volume unit grid. Each path point (including its direction vector) is mapped to the volume unit where it is located according to its three-dimensional coordinates, forming a path point set and a direction vector set in the unit. For each volume unit, the direction vector of the path point set is adjusted based on the obtained angle adjustment value: ; based on the obtained angle adjustment value, each direction vector is corrected: Covariance matrix analysis is performed on the corrected direction vector set to construct matrix , and its eigenvalues and eigenvectors are calculated, where is the direction vector of the th path point after angle adjustment; is the average value of the direction vector set; is the vector transpose operation. The eigenvector corresponding to the maximum eigenvalue is taken as the main direction of the fiber of the unit , and the eigenvector corresponding to the second largest eigenvalue is taken as the secondary direction , thereby obtaining a second direction distribution map.

[0035] Step S5: taking the main direction vector of the second direction distribution map as the main axis direction and the secondary direction vector of the fiber as the transverse reference direction orthogonal to the main axis, and combining the preset material anisotropic properties to perform fiber direction simulation verification, thereby obtaining the fiber direction simulation result.

[0036] In this embodiment, for each volume unit, a local coordinate system is established, taking as the main axis direction, as the transverse reference direction, as the thickness direction, to form a fiber space directional coordinate system. The local coordinate system direction is mapped to the anisotropic properties in the material database, such as the tensile modulus of the main axis direction, the transverse modulus , the shear modulus , etc., to construct a third direction distribution map, i.e. a “material performance direction map”. The third direction distribution map is integrated with the three-dimensional finite element model of the component, the layer properties, mesh division and boundary conditions are introduced, and the structural simulation is performed in the finite element software (such as ABAQUS or ANSYS) to obtain the stress-strain response and anisotropic behavior. The direction response (such as the elastic modulus of the main axis direction) of each unit in the simulation result is compared with the target value in the material library, and the difference value is calculated; anisotropic response (such as the principal direction modulus) extracted from the simulation results, a target attribute value provided in the material database. If the maximum difference value (for example, 2%), the perturbation sensitivity coefficient is updated according to the difference gradient feedback , the angle adjustment amount is updated, steps S4 and S5 are repeated until the error converges, and finally the fiber direction distribution diagram that passes the simulation verification is output.

[0037] Optionally, step S1 comprises:

[0038] Step S11: Collecting the fiber laying track through the process control interface connected with the automatic fiber laying device;

[0039] In the embodiment of the present application, in the process of automatic carbon fiber laying forming, a data channel is established with the laying machine control unit (such as FANUC controller or Siemens PLC) of the automatic laying device, and the track data in the fiber bundle laying process is collected in real time. The collected data includes but is not limited to: three-dimensional coordinate values of track path points in the workpiece coordinate system, laying speed, tool posture angle information (such as rotation angle around the tangent of the workpiece), channel number and time stamp, etc. The track data is recorded at a frequency of 10ms sampling period, and packed to form a track sequence file for subsequent geometric deviation analysis and path reconstruction processing.

[0040] Step S12: Projecting the path points of the fiber laying track into the component surface coordinate system in the preset forming component CAD model, and calculating the position error of the path points in the surface tangent and normal directions based on the deviation between the local normal vector of the component surface and the tangent vector of the path point;

[0041] In the embodiment of the present application, the forming component CAD model is called, and the parametric coordinate system of each surface element in the model is extracted, including the surface tangent vector pair and the normal vector. For each collected path point, based on its nearest neighbor distance relationship, it is projected onto the CAD surface to obtain the projection point on the surface, and the local surface tangent and normal vectors are read at the point. Further, by comparing the angle deviation between the path point tangent direction and the surface normal, the deviation distance of the path point in the surface normal direction is estimated as the normal error; at the same time, the projection length of the path point on the surface tangent base is compared with the ideal laying path to obtain the tangent error.

[0042] In another embodiment, the error calculation uses a sliding window mode of every 5mm path distance as a group, which can ensure the stable extraction of the continuous distribution trend of the error.

[0043] It is noted that the forming component CAD model refers to a three-dimensional modeling file describing the shape of the target composite material component, usually stored in an industry standard format such as.STEP,.IGES,.SLDPRT or.STL, and generated by computer-aided design (CAD) software such as SolidWorks, UG NX, CATIA or Creo, etc. The model not only contains the geometric outer contour surface information of the component, but also includes the definition of the parametric surface patch for spatial fitting and path projection processing. In actual operation, a local coordinate system of the surface of the forming component is constructed based on the CAD model, and the local tangent vector (U, V direction) and normal vector (N direction) of the surface are extracted for trajectory projection and path error calculation. If the CAD model contains assembly reference surface, connection boundary or forming mold partition information, such information can also be called to automatically divide the laying area and classify the path segments.

[0044] In other embodiments, the ideal laying path refers to a theoretical fiber laying trajectory sequence designed by a process engineer in a CAD / CAM environment according to the component surface characteristics, fiber direction requirements and forming process constraints. It is usually defined in point sequence or tool path format and contains spatial coordinates, direction vectors, laying sequence and speed information, etc.

[0045] Step S13: identifying the path segment to be corrected in the fiber laying trajectory according to the position error of the path point in the tangent and normal directions of the surface;

[0046] In embodiments of the present application, based on a preset process error tolerance threshold (for example, normal error 0.5mm, tangent error 1.0mm), error judgment is performed on each path point. If the error values of the continuous path points in a path segment exceed the threshold, the path segment is determined as an abnormal path segment. In the identification process, a dynamic path segment sliding window identification method is used to extract a segment with more than N points (such as N=5) exceeding the error limit from the path point sequence, and the start and end indexes are labeled. If there are multiple intermittent abnormalities in a path segment, further fusion of adjacent abnormal point segments is performed, and the overall length, path deviation trend and upstream and downstream path continuity are jointly evaluated, and finally the set of path segments to be corrected is output.

[0047] It is noted that if there are multiple discontinuous abnormal point segments in a path segment, further merging adjacent abnormal point segments means that in the actual track error identification process, when there are multiple error point segments with short intervals (such as less than the set time window T=0.5s or path distance D=15mm) in a certain section (i.e. the error points show "jumping distribution"), these mutually adjacent but non-continuous abnormal point segments will be merged. The fusion process can include but is not limited to: if the time interval of two abnormal point segments is less than the set time window threshold, or the distance between the space path points is less than the set threshold (such as 10~20mm), it is considered as an integral abnormal segment; if the error directions of adjacent abnormal segments (such as both downward deflection) have the same direction, it is determined that they are the same kind of abnormality, and the segment fusion is performed; by fitting the error variation trend curve of the abnormal segment boundary, it is determined whether there is a missed error point ("missed segment") between the two segments to prevent misclassification.

[0048] In another embodiment, the joint evaluation of the overall length, path offset trend and upstream and downstream path continuity means that when identifying multiple path abnormal segments and determining whether they need to be merged or processed separately, the following three aspects are analyzed comprehensively: 1) overall length evaluation: if the length of a single abnormal segment is less than the minimum control threshold (such as 20mm), but it appears continuously in a certain area and the total length exceeds the set upper limit (such as 80mm), it is treated as a continuous abnormal segment that needs to be corrected as a whole; avoid misjudging small error segments as negligible, thereby missing potential curvature deformation areas. 2) path offset trend analysis: the direction consistency of the error vector sequence of each abnormal path segment is determined (such as multiple point error downward deflection, which is a consistent trend); if the continuous abnormal segment shows the same direction of deflection (such as negative deflection increases), it is considered that these abnormal points are caused by the same working condition or path planning logic failure. 3) upstream and downstream path continuity detection: check the tangent direction and curvature change of the normal path segments on both sides of the abnormal segment; if the abnormal segment and the normal segments before and after it have obvious angle mutation or curvature discontinuity (such as the tangent direction angle is greater than 10° or the curvature change rate is greater than 0.05 / mm), it is recommended to be processed separately; otherwise, it can be included in the unified path segment for integrated reconstruction.

[0049] Step S14: performing curved boundary smoothing fitting on the to-be-corrected path segment based on the curvature continuity of the to-be-corrected path segment and adjacent path segments to obtain a fitted path segment;

[0050] In the embodiment of the present application, the first and last points of each path segment to be corrected are extracted, and 3 to 5 path points in the adjacent normal path segments before and after the first and last points are selected as the fitting boundary control points. In order to ensure the continuity and physical realizability of the fitted path, a fitting algorithm based on cubic B-spline is used to construct a smooth curve, the curvature variation trend is constrained to ensure that the tangent direction and curvature value of the fitted path at the connection boundary are consistent or similar to those of the adjacent path segments. In the fitting process, a fitting residual control threshold (such as the maximum fitting residual is not more than 0.2 mm) is set, and the control point weight is automatically adjusted to ensure that the fitted path segment is continuous and smooth in space without mutation. After the fitting is completed, the fitted path segment is used as an updated path to replace the original error segment and is connected to the original trajectory sequence.

[0051] Step S15: Based on the differential direction vector relationship between the path points in the fitted path segment, the instantaneous tangent direction of the path points is calculated as the new tangent direction of the path segment, and the fiber laying correction trajectory is obtained.

[0052] In the embodiment of the present application, forward difference processing is performed on the coordinates of each pair of adjacent path points in the fitted path segment, the differential displacement vector is calculated, and the vector is unitized as the instantaneous tangent direction of the path point. The tangent direction is used for subsequent fiber direction calculation, laying head posture control and forming quality simulation. In order to improve the stability of the direction vector, the system further performs sliding weighted average processing after calculating the differential direction, and performs vector weighted smoothing processing on the direction vectors of the continuous 3 to 5 path points to avoid local posture mutation caused by small disturbances. The finally updated path segment includes: updated three-dimensional space coordinates, new tangent direction vector, curvature information and local direction gradient value, which constitutes the fiber laying correction trajectory segment, and is spliced into a complete trajectory sequence with the front and rear path segments.

[0053] Fig. 2 The first direction distribution diagram in the embodiment of the present application is shown in FIG. 1. As shown in FIG. 1, the space region is divided based on a grid, and a plurality of directional arrows are drawn in each grid unit, wherein the red arrows represent the local tangent direction (i.e. the fiber laying direction) of the path points in the region, and the blue dots represent the path points of the correction trajectory. Fig. 2

[0054] The first direction distribution diagram reflects the fiber laying trajectory direction distribution of the composite material component in the actual forming process. As can be seen, there are local concentrated changes or intersection phenomena of the fiber direction in multiple grid regions, especially in the regions with high arrow density or direction convergence, which indicates that the path points have a laying direction mutation or spatial superposition in these regions, which may correspond to the interlaminar overlap, curvature mutation or path disturbance in the actual component.

[0055] In addition, as shown in FIG. 2, the second direction distribution diagram in the embodiment of the present application is shown in FIG. 2. As shown in FIG. 2, the space region is divided based on a grid, and a plurality of directional arrows are drawn in each grid unit, wherein the red arrows represent the local tangent direction (i.e. the fiber laying direction) of the path points in the region, and the blue dots represent the path points of the correction trajectory. Fig. 2 ​As shown, in the first direction distribution map, part of the red arrow profile is clear and the direction is clear, and part of the arrow presents a blurred and divergent visual effect. The main reason is that there are differences in the local spatial curvature and normal disturbance degree of the component surface where different path points are located.

[0056] Specifically, the area where the arrow is relatively clear usually corresponds to the area where the curvature of the component surface is relatively small and the laying path is relatively smooth and continuous. At this time, the projection of the path point in the tangent direction of the surface is stable, the direction vector has consistency, and a relatively regular directional distribution is formed. The area where the arrow is blurred or divergent is usually located in the high-curvature area of the component surface or between adjacent layers where the normal of the surface changes rapidly. In such areas, the local tangent direction of the path point is greatly affected by the disturbance of the surface normal, the path turning back or local superposition, the projection direction is significantly deviated, and multiple direction vectors interfere with each other in a single unit, presenting a blurred or divergent unstable feature. Therefore, the change in the clarity of the arrow essentially reflects the influence of the spatial topography of the component surface on the consistency of the fiber laying direction, and is an important basis for judging the path disturbance, normal deviation and abnormal laying area.

[0057] Optionally, step S2 comprises:

[0058] Step S21: differentiating the spatial positions between the continuous path points in the differential fiber laying correction trajectory, and extracting the tangent vector of each path point;

[0059] In this embodiment, the spatial positions between adjacent path points in the differential fiber laying correction trajectory are subjected to differential operation, and the relative displacement relationship thereof is extracted, so as to construct a local tangent vector sequence of each path point. The path points in each trajectory have a clear arrangement order, and the instantaneous motion direction of the trajectory can be obtained through piecewise differential processing. The tangent vector represents the main extension direction of the fiber tows on the surface of the component in actual laying.

[0060] In particular, for trajectory segments with uneven path intervals, a local weighted differential method can be used to improve the stability of direction estimation.

[0061] Step S22: calculating a local orthogonal tangent base at any given path point position on the component surface in the formed component CAD model;

[0062] In this embodiment, for each path point position, the projection point thereof is found in the formed component CAD model, and a local coordinate system is defined based on the component surface where the projection point is located. The coordinate system consists of two main tangent directions (which can correspond to u and v directions) and a normal direction that change along the surface direction, and forms an orthogonal base.

[0063] Step S23: projecting the tangent vector of each path point into the local orthogonal tangent base to obtain the direction vector of each path point on the component surface.

[0064] In another embodiment of the present application, the obtained tangent vector is projected into the constructed local orthogonal tangent basis, and a tangent projection vector of the path point in the component surface coordinate system is obtained, and then a direction vector of each path point on the component surface is obtained. The direction vector reflects the actual laying direction of the path point relative to the geometric appearance of the component surface. For regions with large curvature variation, there may be a significant difference between the spatial tangent vector of the path point and its tangent projection on the surface. The projection vector is used to correct the response of the path direction to the surface normal disturbance.

[0065] Step S24: According to the coordinate position of the path point on the component surface coordinate system, the direction vectors of each path point on the component surface are interpolated and spliced to obtain a first direction distribution map.

[0066] In this embodiment, according to the coordinate position of the path point on the component surface, the direction projection vector of each path point is embedded into a set of preset grid structures, and the direction data in each unit is weighted interpolated and graphically spliced according to the component surface parameter space (such as the local coordinate system defined by the component surface). The set of direction vectors in each grid unit is used to draw arrow marks to represent the main fiber laying trend in the region, and finally a first direction distribution map as shown in FIG. 6 is formed. Fig. 2 The red arrows in the figure represent the distribution characteristics of the direction vectors of each path point in the grid unit, and the blue dots represent the corrected key path points of the trajectory. Some arrows in the figure show a clear and unified direction, which usually corresponds to the smooth and stable laying region of the component surface. Some arrows are blurred and divergent, which usually appear in the space region with rapid curvature variation or severe normal disturbance. These phenomena reflect the coupling relationship between local laying consistency and surface disturbance, and are an important basis for subsequent identification of abnormal laying regions and execution of direction field reconstruction.

[0067] In some embodiments, the weighted interpolation and graphical stitching specifically includes: dividing the surface of the shaped component CAD model into a regular two-dimensional grid structure in its local parametric coordinate system (e.g., (u, v) parameter space), and the grid cell size can be adaptively adjusted according to the path point density and the local curvature of the component (e.g., finer grid is used in high curvature areas). For each path point with a known direction vector, the system determines the grid cell in which it is located according to its (u, v) coordinates in the component surface coordinate system, and maps the direction vector of the path point into the grid cell. For each grid cell, the system extracts the direction vectors of all the path points belonging to the cell, and calculates the representative direction of the area. To improve the smoothness and local consistency of the direction estimation, a weighted interpolation method is used to calculate the mean direction vector. The weight can be determined according to the distance between the path point and the center of the grid, and the closer the distance, the higher the weight. A Gaussian kernel function or inverse distance weighting (IDW) model is commonly used for weighting. For some grid cells without path points falling into them (e.g., edges or sparse areas), neighborhood diffusion or surface interpolation is used to introduce direction information from adjacent valid grid cells, to achieve local continuity completion and avoid direction map breaks. After the direction interpolation is completed, the representative direction vector of each grid cell is drawn on the component surface graph in the form of an arrow, with the arrowhead at the center of the grid, and the direction and length representing the average direction and laying trend intensity of the fiber laying in the area.

[0068] Optionally, the step S3 of identifying the surface overlapping intersection area includes:

[0069] Based on the first direction distribution map, a tangential direction vector of each path point in each path in the tangential direction of the component surface is extracted, and a rectangular projection band is constructed along the tangential direction of the component surface by extending half of the preset direction bandwidth value on both sides of the tangential direction vector, to determine the coverage range of each path direction.

[0070] In this embodiment, for each path point in each fiber laying correction trajectory, a direction vector of the path point in the tangential direction of the component surface is extracted in the first direction distribution map as the main extension direction reference of the path point. Then, a rectangular projection band area is constructed along the tangential direction by extending half of the preset direction bandwidth value (e.g., in millimeters, such as a direction bandwidth of 2.0 mm) on both sides of the direction vector, to form the influence area of the path in the component surface coordinate system. The rectangular projection band is constructed point by point with the path point as the center, and then spliced and fused along the path point sequence, to finally form a continuous band-shaped area covering the entire path.

[0071] The spatial overlapping area of the rectangular projection band is solved to identify the area where two or more fiber paths overlap or penetrate each other on the component surface, to obtain a path intersection candidate area.

[0072] In this embodiment, based on the obtained path rectangular projection bands, the detection of the spatial overlapping area is performed in the component curved surface coordinate system. Specifically, the boundary overlap calculation is sequentially performed on the projection bands of any two paths. If there is a significant intersection or interpenetration trend (for example, the overlapping length exceeds a set threshold or there is an intersection angle) between the two paths in the curved surface space, the spatial position can be marked as a path intersection candidate area. The intersection candidate area generally shows the intersection or interpenetration of multiple path projection areas in the local space, which may correspond to the mutual stacking, twisting or abnormal behavior of the trajectory of the laying path in the actual working condition.

[0073] It is noted that the overlapping length exceeds the set threshold, which is determined according to the design size of the composite component, the fiber laying process precision and the structural safety requirement. Generally, the reasonable threshold interval is in the range of 2 mm to 10 mm, which is flexibly adjusted according to the following factors: the high-precision automatic fiber laying equipment allows the threshold to be set smaller (for example, 2 to 5 mm) to capture the small path overlapping risk; the larger or thicker component can appropriately relax the threshold (for example, 5 to 10 mm) to avoid excessive sensitivity leading to frequent misjudgment.

[0074] According to the laying sequence of the paths in the fiber laying correction trajectory, the path pairs with upper and lower layer relationship in the path intersection candidate area are extracted, and the interlayer spacing and intersection angle in the normal direction of the component curved surface are calculated for each path pair.

[0075] In this embodiment, after identifying the intersection candidate area, the path pairs with clear upper and lower layer relationship are further extracted in combination with the time sequence or hierarchical identification of each path in the actual laying sequence. For example, if path A is laid earlier than path B and the two paths coincide in a certain area, it can be considered that path B is above path A. By identifying and pairing all path combinations that meet this condition, a set of path pairs with potential interlayer interference are obtained for subsequent spatial structure evaluation. For each set of upper and lower layer path pairs extracted, the interlayer spacing in the normal direction of the component curved surface and the intersection angle between the tangential direction vectors of the two paths are calculated.

[0076] The path intersection candidate area that simultaneously satisfies the preset interlayer spacing threshold and intersection angle threshold is regarded as the curved surface overlapping intersection area.

[0077] In this embodiment, if the interlayer spacing of a path pair in the intersection area is less than the preset spacing threshold (for example, 0.5 mm) and the intersection angle is greater than the intersection angle threshold (for example, 30 degrees), it is considered that there is a potential physical overlapping or spatial interpenetration risk, and the area can be marked as a curved surface overlapping intersection area. The identification result of the intersection area can be used in subsequent path reconstruction, fiber laying optimization or laying sequence adjustment process correction links to ensure the spatial integrity and structural stability between the layers in the forming process.

[0078] Optionally, the step S3 of calculating the fiber disturbance offset amplitude of each layer in the normal direction in the curved surface overlapping intersection region comprises:

[0079] The rectangular projection band corresponding to each path in the curved surface overlapping intersection region is extracted, and the center position of each path in the local curved surface normal direction is calculated according to the normal coordinates of the path points on the component curved surface in the component CAD model;

[0080] In the embodiment of the present application, for the identified curved surface overlapping intersection region, first, the rectangular projection band corresponding to each fiber path involved in the region is extracted in sequence, and the projection band is constructed based on the tangential direction vector of the path point and the preset direction bandwidth value, covering the main extension direction of the path on the curved surface and the influence range. The normal mapping of each path point in the rectangular projection band in the corresponding curved surface parameter coordinate system in the component three-dimensional CAD model is performed to obtain the projection value of each path point in the normal direction of the curved surface (i.e. the direction of the unit normal vector). The average value of the normal coordinates of all points in each rectangular projection band is taken as the center normal position of the path in the overlapping region, that is, the center elevation reference of the path in the region.

[0081] In one implementation manner of the embodiment of the present application, if the rectangular projection band of path A in a certain overlapping region contains 68 path points, the average value of the normal height values of the 68 points is calculated to obtain the center normal height of path A in the region as 12.38 mm; similarly, the center normal height calculation result of path B is 13.02 mm.

[0082] The center positions are sorted according to the laying sequence, and the relative height difference of the corresponding upper path in the normal direction is calculated layer by layer with the lower center position in the laying sequence as the reference benchmark to obtain the initial interlayer distance;

[0083] In the embodiment of the present application, the paths are sorted according to the time sequence or hierarchical coding of fiber laying to determine the path relationship between the upper and lower layers. Then, the normal center position of the path above is calculated by difference with the center normal height of the lower path as the benchmark to obtain the initial interlayer distance between the path pairs. The interlayer distance represents the theoretical interlayer spacing of the path in the normal direction under the condition of no disturbance, and is a basic parameter for subsequent disturbance influence judgment.

[0084] In one implementation manner of the embodiment of the present application, the laying serial number of path A is #12, and the serial number of path B is #17, indicating that path A is laid before path B. The normal center height of path A is 12.38 mm, and the normal center height of path B is 13.02 mm, so the initial interlayer distance of the path pair is 0.64 mm.

[0085] Determine the normal offset tendency of each path according to the path curvature and the laying sequence in the fiber laying correction trajectory;

[0086] In the embodiment of the present application, based on the fiber laying correction trajectory of each path, the curvature change of the path in the overlapping intersection area is extracted, the local geometry of the component surface where the path is located (such as the concave-convex change of the surface, local corner, etc.) and the laying direction are combined, and the normal offset tendency vector of the path is calculated by using a fitting algorithm. If the path curvature is larger, or it is in a local area where the curvature changes sharply, it usually indicates that a certain offset or bending may occur during the laying process, forming a normal disturbance. The tendency vector is in millimeters, a positive value indicates deviation from the normal direction upwards, and a negative value indicates downwards.

[0087] In one implementation manner of the embodiment of the present application, path B presents a concave trajectory in the overlapping area, and the average curvature is 0.021 , combined with the local surface concave tendency, the normal disturbance tendency of path B is calculated as +0.22 mm; path A is in a relatively flat area, and the disturbance tendency is only +0.04 mm.

[0088] The normal offset tendency is superimposed on the initial interlayer distance between the path pairs to obtain the fiber disturbance offset amplitude of each layer path in the normal direction.

[0089] In the embodiment of the present application, the obtained initial interlayer distance and the obtained normal disturbance tendency are numerically superimposed as the fiber disturbance offset amplitude in the normal direction between the actual paths. The amplitude can be used to judge whether to trigger the physical interference judgment condition, such as less than a certain spacing threshold (such as 0.5 mm) and the disturbance angle is greater than a limited angle (such as 30°).

[0090] In one implementation manner of the embodiment of the present application, the initial interlayer distance of path A and path B is 0.64 mm, the normal disturbance tendency of path B is +0.22 mm, and the final disturbance offset amplitude is: 0.64 mm-0.22 mm=0.42 mm. Since the disturbance offset amplitude is less than 0.5 mm, and under the premise that the intersection angle is greater than 30 degrees, the path pair is judged as a possible physical contact or interlacing risk area, which can be included in the identification result of the surface overlapping intersection area.

[0091] Optionally, the step S3 of calculating the angle adjustment amount of the direction vector comprises:

[0092] The path pairs with upper and lower layer relationship in the surface overlapping intersection area are extracted, the angle between the laying direction vectors of the path pairs is calculated, and an initial angle value is obtained;

[0093] In the embodiment of the present application, the path pairs with established upper and lower layer relationship are extracted from the overlapping intersection area of the curved surface. Each path can be represented as a spatial curve segment composed of continuous path points in the laying process, and the tangent direction vector at the corresponding position in the path segment is selected as the laying direction vector of the path. For each pair of upper and lower paths, the corresponding tangent vectors in the overlapping area are selected, and the initial included angle value between the laying direction vectors is calculated according to the three-dimensional vector included angle formula. The included angle is used to measure the relative laying direction difference of the upper and lower paths in the laying process, and is one of the important parameters for judging the interference and offset risk of the paths.

[0094] In an implementation manner of the embodiment of the present application, path A is the lower layer path, and path B is the upper layer path, and the laying direction vectors of the paths in the overlapping area are vector VA=(0.92, 0.12, 0.36) and vector VB=(0.88, 0.14, 0.45) respectively. The vector included angle calculation formula is used to calculate the initial laying direction included angle value of the path pair in the area as follows:

[0095] The fiber disturbance offset amplitude is normalized, and a correction factor is constructed by combining a preset disturbance sensitivity coefficient, and the correction factor is multiplied by the initial included angle value to calculate the included angle adjustment amount of the direction vector.

[0096] In the embodiment of the present application, the fiber disturbance offset amplitude calculated in the normal direction for each path pair is normalized by using a preset standard disturbance interval (such as 0 to 1 mm). The normalization processing standardizes the offset amplitude to a value between 0 and 1. The normalized result, in combination with the disturbance sensitivity coefficient K (range 0.5 to 2.0) preset for different materials and laying scenes, together constitutes an amplification or inhibition factor for the included angle correction. The correction factor is used to dynamically adjust the judgment sensitivity of the included angle between the paths.

[0097] In an implementation manner of the embodiment of the present application, the disturbance offset amplitude of the path pair is 0.42 mm, and the normalized result is If the current material type is high modulus carbon fiber, which is sensitive to directional disturbance, and the preset disturbance sensitivity coefficient is K=1.5, then the correction factor can be calculated as .

[0098] In the embodiment of the present application, the initial included angle value calculated and the disturbance correction factor calculated are multiplied to obtain the final included angle adjustment amount . The adjustment amount is used to correct the original included angle judgment value, and can be further used to adjust the laying path strategy or judge the potential interference risk level.

[0099] In an implementation manner of the embodiment of the present application, the initial included angle value is ​, the correction factor is 0.63, the calculated angle adjustment is: ; the angle adjustment indicates that the influence of the original path direction difference on the laying interference risk is equivalent to about actual laying deflection angle after considering the disturbance offset effect. If the value exceeds the system set interference warning threshold (such as ), it is determined that the path has a high directional interference risk, and further path optimization or interlayer compression adjustment is required.

[0100] Optionally, the step S4 of dividing the first direction distribution map into finite volume units comprises:

[0101] Based on the spatial positions of the path points in the first direction distribution map on the component surface of the forming component CAD model, a continuous region with a path point density greater than a preset laying density threshold is extracted to obtain an effective path distribution region;

[0102] In an embodiment of the present application, by analyzing the mapping coordinates of each path point in the first direction distribution map in the component CAD model, the number of path points in a unit area range is counted according to the projection relationship on the component surface, thereby constructing a path point density distribution map. The preset laying density threshold can be set according to the component material type, path control accuracy and process requirements, for example, set to 30 path points per square centimeter. A sliding window (such as 2mm x 2mm) is used to scan the entire component surface area, and the region with a path point density continuously exceeding the threshold is identified and extracted as an effective path distribution region according to a connectivity clustering algorithm (such as a 4-neighbor aggregation rule).

[0103] In one implementation manner of the embodiment of the present application, the component surface area is a complex curvature hyperboloid, and there are 15,380 path points recorded in the first direction distribution map. A 2mm x 2mm sliding window is used to traverse the CAD surface, and a plurality of continuous regions with a path density exceeding 40 points / cm² are extracted. After region aggregation and boundary rejection, three effective path distribution regions are finally identified, with the maximum region size being 56mm x 88mm and the minimum being 18mm x 27mm, which are used for subsequent space division and volume modeling.

[0104] The maximum vertical spacing of each path point in the effective path distribution region on the component surface and in the thickness direction of the adjacent layer is taken as the division spacing, and the component surface coordinate system is equally divided in the normal direction of the component surface according to the division spacing, to obtain initial finite volume units;

[0105] In the embodiment of the present application, the maximum vertical distance in the effective path distribution area is calculated as the division distance d by further extracting the projection distance of all path points in the effective path distribution area on the normal direction of the component surface. To ensure the accuracy of the structure modeling and disturbance calculation, the division distance can be set to the maximum distance value rounded up to a set accuracy level (such as 0.1 mm). Then, taking the component surface as the reference surface, combining the normal direction (obtained by derivation of the CAD surface), and constructing a plurality of layers of parallel planes with the division distance d as the unit from the upper and lower layers of the surface, the spatial framework is constructed by expanding the boundary profile of the effective path distribution area along the tangential direction, and finally the initial finite volume element set covering the effective path area is formed.

[0106] In one implementation manner of the embodiment of the present application, an effective path distribution area contains 12 layers of upper and lower path layers, and it is found by statistics that the maximum path point normal direction distance is 2.35 mm, and the rounding distance is set to 0.5 mm. Then, 5 groups of interlayer slices are constructed in the normal direction from the surface outward in the area, and 6 layers of spatial partition areas are formed. Each interlayer section is kept normal parallel to the component surface, and the initial finite volume element is constructed by forming a closed grid through the boundary of the horizontal path area, and a total of 312 finite element bodies are generated.

[0107] According to the positional relationship of each path point in space, the spatial coordinates of each path point in the first direction distribution map and the corresponding laying direction vector are mapped into the initial finite volume element to obtain the finite volume element.

[0108] In the embodiment of the present application, the spatial inclusion judgment is performed on the coordinate position of the path point in the three-dimensional space (obtained by real-time generation of the three-dimensional path control or mapping through the CAD surface) and the spatial boundary of the initial finite volume element. The bounding box is constructed to quickly judge whether the path point is inside a certain volume element, and if it is satisfied, the path point is classified into the element. Further, the laying direction vector (tangent vector) carried by the path point is mapped into the volume element to form the direction field distribution in the unit volume. After a plurality of path points are classified into the same volume element, the average laying direction, the direction difference degree (such as the angle variance) and other structure parameters can be counted, which are used for subsequent interference judgment, disturbance propagation modeling and laying optimization analysis.

[0109] Optionally, the spatial distribution relationship between the main direction of the fiber and the secondary direction of the fiber in step S4 includes:

[0110] The direction vector adjustment amount is used to adjust the direction vectors of all path points in the finite volume element to obtain an adjusted direction vector set;

[0111] In the embodiment of the present application, for each constructed finite volume element, the angle adjustment amount between the paths obtained in the foregoing steps is used to adjust the direction vectors of all path points in the finite volume element to obtain an adjusted direction vector set. ), the original direction vector of each path point in the unit is angle-corrected. Specifically, if the included angle formed by a path point and its adjacent path point exceeds the adjustment threshold, the direction vector of the path point is linearly interpolated or slightly rotated in the direction of to make it more consistent with the local principal direction.

[0112] In one specific implementation, assuming that the original direction vector of a path point is , the direction adjustment amount of the finite volume unit in which the path point is located is , and the corresponding target adjustment direction is the unit vector (which can be the adjacent principal direction vector or the local average direction), the new vector of the direction vector after adjustment is , which can be expressed as: ; wherein represents a rotation matrix for a small-angle rotation in the direction . In this embodiment, if a unit contains 6 path points, and the calculated is in the range of 5.2° to 11.8°, then according to the adjustment amount, a fine-tuning operation is performed on the direction vector of each path point to obtain the adjusted direction vector set.

[0113] In some embodiments, when performing the direction vector adjustment operation, according to the path pair number in which the path point is located, the corresponding included angle adjustment amount and perturbation sensitivity coefficient are first extracted, and a direction offset judgment quantity for fine-tuning is constructed. The physical meaning of the judgment quantity is that the direction vector of the path point should deviate from the original direction to what extent to approach the direction of the lower layer path and reduce the angle mutation between the layers. If the included angle adjustment amount is positive, it means that the current path direction should deviate from the lower layer direction; if the included angle adjustment amount is negative, it means that the current path direction has been excessively deviated from the lower layer direction and should be partially adjusted. The deviation processing is performed in a small-angle rotation manner in a three-dimensional coordinate system, and the adjustment amplitude is limited by the preset fine-tuning tolerance threshold, which does not exceed 10% of the original direction vector included angle.

[0114] For example, in a high-density path area, if it is detected that the upper layer path has a significant tilting deviation trend relative to the lower layer path, and the included angle adjustment amount is positive, then the direction vector of the upper layer path point is slightly rotated clockwise or counterclockwise so that it gradually approaches the direction of the lower layer path; if the adjustment amount is negative, then the direction is opposite. This fine-tuning action can effectively reduce the dispersion degree of the path point direction in the finite volume unit. If the included angle adjustment amount is close to zero, it means that the direction difference of the path pair in the normal direction is negligible and does not need to be adjusted.

[0115] The covariance matrix of the adjusted direction vector set is calculated, and eigenvalues and corresponding eigenvectors of the covariance matrix are decomposed, the eigenvector corresponding to the maximum eigenvalue is taken as the main direction vector of the fiber, and the eigenvector corresponding to the second maximum eigenvalue is taken as the secondary direction vector of the fiber.

[0116] In the embodiment of the application, for the direction vector set of the path point in each finite volume unit which has been adjusted, spatial statistical analysis is performed to identify the main fiber laying direction and the secondary disturbance trend in the region. Based on the obtained adjusted direction vector set, a covariance matrix of the distribution of the direction vector in the three-dimensional space is constructed. The covariance matrix is used to reflect the joint variation trend of the direction vector of the path point in different coordinate axis directions, and the numerical value represents the strength of the correlation between different direction components. Specifically, by statistically analyzing the overall variation of each component in the direction vector of the path point, the aggregation and dispersion of the vectors along each direction in the three-dimensional coordinate space can be comprehensively judged.

[0117] In one implementation manner of the embodiment of the application, for a certain spatial finite volume unit, the direction vectors of all path points in the unit are extracted, and the spatial distribution characteristics of each path point direction vector are calculated one by one with a unified local coordinate system as a reference, and then a direction vector covariance matrix in the unit is constructed. This matrix constitutes the basic structure for describing the overall direction distribution characteristics in the unit. Subsequently, the covariance matrix is subjected to eigenvalue analysis processing, and the main characteristic direction representing the direction variation trend is identified. In this process, the covariance matrix is decomposed into a plurality of eigenvectors and corresponding eigenvalues. Among them, the eigenvector corresponding to the maximum eigenvalue represents the direction in which the direction of the path point varies most concentratedly, and is defined as the main direction vector of the fiber in the finite volume unit. The eigenvector corresponding to the second maximum eigenvalue represents the aggregation trend in the path disturbance or the non-main direction, and is defined as the secondary direction vector of the fiber.

[0118] For example, in a certain fiber laying region, the direction of the path point shows obvious consistency in the length direction of the component, the covariance matrix extracted in this direction has the maximum variation, and the corresponding eigenvector is the main direction vector; and the path offset in the width direction of the component is small, but there is a certain distribution characteristic, and the direction vector associated with the second maximum eigenvalue is identified as the secondary direction vector. The main direction vector and the secondary direction vector are in orthogonal relationship.

[0119] The fiber direction distribution relationship of the main direction vector of the fiber and the secondary direction vector of the fiber is integrated to obtain a second direction distribution map.

[0120] In the embodiment of the present application, based on the principal direction vector and the secondary direction vector information extracted from all the finite volume elements, they are remapped back to the component surface coordinate system according to the path space position. By combining the center point coordinates of each element with its corresponding fiber principal direction and secondary direction, a second direction distribution map is constructed. The second direction distribution map not only contains the fiber principal laying direction of each spatial region, but also captures the local direction disturbance trend and laying consistency information, which is the key basis for subsequent path planning optimization, forming stress estimation and interlayer disturbance analysis.

[0121] In some embodiments, the second direction distribution map can be visualized as: a vector field map on the component surface (the principal direction with a long arrow, the secondary direction with a short arrow); or an ellipse or direction pyramid is drawn with the direction tensor principal axis direction of each element, for three-dimensional printing path disturbance identification.

[0122] The second direction distribution map finally formed in this embodiment contains 624 vector pair nodes, covering about 95% of the effective laying area of the component surface, and reflecting significant differences in fiber direction concentration in different areas, providing important input basis for subsequent laying correction, direction disturbance modeling and stress control analysis.

[0123] Optionally, step S5 comprises:

[0124] Step S51: constructing a local coordinate system for each finite volume element, taking the fiber principal direction vector corresponding to each finite volume element in the second direction distribution map as the principal axis direction, and taking the fiber secondary direction vector orthogonal to the principal axis direction as the transverse reference direction;

[0125] In the embodiment of the present application, in order to accurately depict the spatial orientation of the fiber direction in each region of the component surface, a local coordinate system is constructed based on the principal direction vector and the secondary direction vector of each finite volume element in the second direction distribution map. Specifically, first, all finite volume elements in the second direction distribution map are traversed, and the fiber principal direction vector and the secondary direction vector corresponding to each element are extracted. The fiber principal direction vector is taken as the principal axis direction of the local coordinate system, which is used to represent the main stress direction of the material in this region; at the same time, the fiber secondary direction vector orthogonal to the principal axis direction is set as the local transverse reference direction, which is used to assist in establishing the reference system of the anisotropic material performance direction.

[0126] In a typical application scenario, if the principal direction of a certain element extends along the longitudinal laying direction of the component, it will be marked as the X-axis direction of the element; if the secondary direction is uniformly distributed in the width direction of the component, it will be set as the Y-axis direction, and the normal direction corresponds to the Z-axis. Finally, an independent local three-dimensional coordinate system is generated for each finite volume element, which provides a direction reference for subsequent material attribute mapping and simulation analysis.

[0127] Step S52: mapping the principal axis direction and the transverse reference direction in the local coordinate system of each finite volume element to the preset mechanical properties and transverse properties of the material anisotropy attribute respectively, and constructing a third direction distribution map;

[0128] In the embodiment of the present application, according to the constructed local coordinate system, the direction vector of each finite volume element is mapped to the mechanical property parameter direction corresponding to the material anisotropy attribute. Specifically, the fiber main direction corresponding to the principal axis direction in the local coordinate system is mapped to the preset longitudinal property parameter direction (such as elastic modulus, tensile strength, etc.) in the material database; the transverse reference direction is mapped to the transverse property parameter direction. In this way, a one-to-one correspondence between the direction and the mechanical attribute is established in each element, forming an anisotropy performance mapping driven by the fiber direction. The mapping relationship is integrated into the third direction distribution map, which not only contains the information of the fiber direction, but also clearly shows the spatial distribution of the anisotropy material performance in different regions of the component, which is used to support the subsequent simulation and response analysis of the mechanical behavior.

[0129] Step S53: inputting the third direction distribution map into a preset finite element model to perform composite material mechanical simulation, and obtaining anisotropy response results;

[0130] In the embodiment of the present application, the third direction distribution map is imported as input data into a preset finite element simulation model to perform anisotropy response simulation of the composite component. The corresponding element type, mesh structure and boundary conditions have been defined in the simulation model. According to the primary and secondary directions of each element provided in the third direction distribution map, the anisotropy attribute of the material is automatically loaded onto the corresponding mesh element, realizing the mechanical modeling of the directional material performance and structure coupling. Then, the load, boundary or thermal field conditions consistent with the actual working conditions are applied, and the solving calculation process is performed. The simulation output results include stress distribution, displacement response, interlaminar shear, local deformation and other indicators of the component under different loads, reflecting the real stress state of the composite material under the direction-dependent condition.

[0131] Step S54: comparing the attribute difference value of the material anisotropy attribute and the anisotropy response results to obtain the fiber direction simulation results; if the attribute difference value of the fiber direction simulation results is greater than the preset difference value threshold, adjusting the perturbation sensitivity coefficient according to the attribute difference value gradient to update the included angle adjustment amount of the direction vector, and then iteratively performing steps S4 to S5 until the attribute difference value is less than the preset difference value threshold; if the attribute difference value of the fiber direction simulation results is less than the difference value threshold, the second direction distribution map is the actual fiber direction distribution map of the composite component.

[0132] In an embodiment of the present application, the simulation results are analyzed, and the anisotropic response results obtained in the simulation are compared with the anisotropic mechanical properties preset in the material design stage on a unit-by-unit basis, and the attribute difference value between the two is calculated. If the simulation response of a certain unit deviates from the preset material properties in the main direction or the transverse direction by more than the difference value threshold (such as the elastic modulus error exceeding 5%), it is determined that there is a risk of fiber orientation error or insufficient correction of direction disturbance in this area. According to the gradient information of the difference value in the spatial distribution, the value of the disturbance sensitivity coefficient is adjusted in reverse, thereby affecting the calculation results of the subsequent angle adjustment amount. The adjusted disturbance sensitivity coefficient will be used to update the angle adjustment amount of the path point direction vector, and then steps S4 to S5 are re-executed, including direction vector adjustment, covariance analysis, local coordinate system construction, and simulation analysis processes, forming an iterative closed loop. After the difference value is less than the preset threshold, it is considered that the current second direction distribution map has sufficiently met the material anisotropic performance distribution requirements, and it can be used as the final fiber direction distribution result of the composite material component for subsequent process path planning and manufacturing execution links.

[0133] In another embodiment of the present application, first, the attribute difference values of all finite volume elements in the current round of simulation results are statistically analyzed. The difference value is defined as the absolute or relative deviation between the simulation output of the unit direction performance and the expected design value. For example, the main direction elastic modulus error, the transverse tensile strength error, etc. Then, based on the component surface coordinate system, the attribute difference value is discretely processed in space, and the local change rate of the difference value in the main direction and the transverse direction is calculated using a gradient operator (such as central difference), forming a difference gradient field. The gradient value reflects the intensity of the change in material response in space. For the area where the difference gradient exceeds the set threshold (for example, the gradient exceeds 10% / mm), it is considered that this area is highly sensitive to direction disturbance, and the current disturbance correction is insufficient or the direction adjustment is insufficient. If the difference value is large (exceeds the preset deviation threshold) and the gradient value is large, the disturbance sensitivity coefficient is appropriately increased to enhance the amplification effect of the angle adjustment amount in the next round; if the difference value is small but the gradient changes significantly, it is considered that the local direction disturbance is too strong, and the disturbance sensitivity coefficient is appropriately reduced to avoid discontinuity of the path caused by excessive adjustment. If the difference value and the gradient are within the threshold range, the disturbance sensitivity coefficient is kept unchanged or slightly adjusted. For example, the initial disturbance sensitivity coefficient is 0.6, which is adjusted to 0.75 in the high sensitivity area and to 0.45 in the low sensitivity area.

[0134] In some embodiments, the single iteration adjustment amplitude is limited to within ±0.1, that is, the new value of the disturbance sensitivity coefficient compared to the last value is not more than 0.1 in each adjustment; the adjusted disturbance sensitivity coefficient is limited to the interval of 0.3 to 0.9 as a whole, avoiding the situation that the disturbance sensitivity coefficient is too small to cause ineffective adjustment or too large to cause excessive path disturbance.

[0135] Optionally, the application provides a composite fiber direction simulation modeling system for performing the composite fiber direction simulation modeling method as described above, the composite fiber direction simulation modeling system comprising:

[0136] a trajectory acquisition module, configured to acquire a fiber laying trajectory through a process control interface connected with the automatic fiber placement device; and correct a bending radius and a unit tangent direction of a path point according to a fitting error of the fiber laying trajectory on a component surface to obtain a fiber laying correction trajectory;

[0137] a tangent direction mapping module, configured to map the tangent direction of each path point in the fiber laying correction trajectory to a tangent base of a preset component CAD model surface to construct a first direction distribution map;

[0138] an included angle adjustment amount calculation module, configured to analyze a coverage range of each path on the component surface in the first direction distribution map, identify a surface overlapping and intersecting area, calculate a fiber disturbance offset amplitude of each layer in the normal direction of the surface overlapping and intersecting area, and calculate an included angle adjustment amount of a direction vector according to the fiber disturbance offset amplitude and a path intersecting angle of the surface overlapping and intersecting area;

[0139] a primary and secondary direction division module, configured to divide the first direction distribution map into finite volume units, use the included angle adjustment amount of the direction vector to represent a spatial distribution trend of a fiber primary direction vector and a fiber secondary direction vector of a corresponding finite volume unit, and obtain a second direction distribution map;

[0140] a simulation module, configured to use the fiber primary direction vector of the second direction distribution map as a main shaft direction, use the fiber secondary direction vector as a transverse reference direction orthogonal to the main shaft, and perform fiber direction simulation verification in combination with preset material anisotropy properties, so as to obtain a fiber direction simulation result.

[0141] Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting, the scope of the application being defined by the appended claims and not by the above description, and it is intended to encompass all variations falling within the meaning and range of equivalents of the elements of the application file.

[0142] The above description is merely one specific implementation of the application, enabling a person skilled in the art to understand or implement the application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the application. Therefore, the application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A simulation modeling method for fiber orientation of composite materials, characterized in that, Applied to automated fiber placement equipment, it includes the following steps: Step S1: Collect the fiber placement trajectory through the process control interface connected to the automatic fiber placement equipment; based on the fitting error of the fiber placement trajectory on the component surface, correct the bending radius and unit tangent direction of the path points to obtain the fiber placement correction trajectory; Step S2: Map the tangent direction of each path point in the fiber placement correction trajectory to the tangent base of the preset CAD model surface of the molding component to construct the first direction distribution map; Step S3: Analyze the coverage area of ​​each path on the component surface in the first direction distribution map, and identify the overlapping and intersecting areas of the surfaces; calculate the fiber disturbance offset amplitude in the normal direction of each layer in the overlapping and intersecting areas of the surfaces, and calculate the angle adjustment of the direction vector based on the fiber disturbance offset amplitude and the path intersection angle of the overlapping and intersecting areas of the surfaces; the calculation of the fiber disturbance offset amplitude in the normal direction of each layer in the overlapping and intersecting areas of the surfaces in step S3 includes: Extract the rectangular projection zone corresponding to each path in the overlapping and intersecting area of ​​the curved surface, and calculate the center position of each path in the local curved surface normal direction based on the normal coordinates of the path points of the rectangular projection zone on the curved surface of the formed component in the CAD model of the component. Arrange the center positions according to the laying order, and use the lower layer center position in the laying order as a reference benchmark to calculate the relative height difference of the corresponding upper layer path in the normal direction layer by layer to obtain the initial inter-layer distance. The normal offset trend of each path is determined based on the path curvature and laying sequence in the fiber laying correction trajectory; The fiber perturbation offset magnitude in the normal direction of each path is obtained by superimposing the normal offset trend with the initial interlayer distance between the path pairs. Step S3 involves calculating the angle adjustment of the direction vector, including: Extract path pairs with an upper and lower layer relationship in the overlapping and intersecting regions of the curved surface, calculate the angle between the paving direction vectors of the path pairs, and obtain the initial angle value; The normalized fiber perturbation offset amplitude is combined with a preset perturbation sensitivity coefficient to construct a correction factor. This correction factor is multiplied by the initial included angle value to calculate the included angle adjustment amount of the direction vector. Step S4: Divide the first directional distribution map into finite volume units, and use the angle adjustment of the directional vectors to characterize the spatial distribution trend of the fiber principal directional vector and the fiber secondary directional vector in the corresponding finite volume units to obtain the second directional distribution map; Step S5: Take the fiber principal direction vector of the second direction distribution map as the principal axis direction, the fiber secondary direction vector as the transverse reference direction orthogonal to the principal axis, and perform fiber direction simulation verification in combination with the preset material anisotropy properties to obtain the fiber direction simulation results.

2. The composite material fiber orientation simulation modeling method according to claim 1, characterized in that, Step S1 includes: Step S11: Collect the fiber placement trajectory through the process control interface connected to the automatic fiber placement equipment; Step S12: Project the path points of the fiber laying trajectory onto the component surface coordinate system in the preset CAD model of the molded component, and calculate the position error of the path points in the tangential and normal directions of the surface based on the deviation between the local normal vector of the component surface and the tangent vector of the path points. Step S13: Identify the path segment to be corrected in the fiber laying trajectory based on the positional error of the path point in the tangential and normal directions of the curved surface; Step S14: Based on the curvature continuity between the path segment to be corrected and the adjacent path segments, perform a smooth fitting of the curved boundary of the path segment to be corrected to obtain the fitted path segment; Step S15: Based on the differential direction vector relationship between path points in the fitted path segment, calculate the instantaneous tangent direction of the path point as the new tangent direction of the path segment to obtain the fiber laying correction trajectory.

3. The composite material fiber orientation simulation modeling method according to claim 1, characterized in that, Step S2 includes: Step S21: Extract the tangential vector of each path point from the spatial position of the continuous path points in the differential fiber placement correction trajectory. Step S22: Calculate the local orthogonal tangent base at any given path point on the surface of the component in the CAD model of the formed component; Step S23: Project the tangent vector of each path point onto the local orthogonal tangent basis to obtain the direction vector of each path point on the component surface; Step S24: According to the coordinate positions of the path points on the component surface coordinate system, interpolate and stitch together the direction vectors of each path point on the component surface to obtain the first direction distribution map.

4. The composite material fiber orientation simulation modeling method according to claim 1, characterized in that, Step S3, which identifies overlapping and intersecting areas of curved surfaces, includes: Based on the first directional distribution map, extract the tangential direction vector of each path point in the component surface in the tangential direction, and construct a rectangular projection band along the component surface in the tangential direction by extending half of the tangential direction vector on both sides according to the preset directional bandwidth value, so as to determine the coverage range of each path direction. Solve for the spatial overlap region of the rectangular projection zone to identify areas on the component surface where two or more fiber paths overlap or intersect, and obtain path intersection candidate areas; Based on the laying order of the paths in the fiber laying correction trajectory, extract the path pairs with upper and lower layer relationships in the path intersection candidate area, and calculate the interlayer spacing and intersection angle in the normal direction of the component surface for each path pair. The path intersection candidate area that simultaneously meets the preset interlayer spacing threshold and intersection angle threshold is taken as the surface overlap intersection area.

5. The composite material fiber orientation simulation modeling method according to claim 1, characterized in that, Step S4, which divides the first directional distribution map into finite volume elements, includes: Based on the spatial position of each path point in the first direction distribution map on the component surface of the CAD model of the formed component, the continuous area with a path point density greater than the preset laying density threshold is extracted to obtain the effective path distribution area. The maximum vertical spacing between each path point in the effective path distribution area on the component surface and in the thickness direction of its adjacent layer is used as the partitioning spacing. Combined with the component surface coordinate system, the component surface is divided at equal intervals in the normal direction of the component surface according to the partitioning spacing to obtain the initial finite volume element. Based on the spatial relationship of each path point, the spatial coordinates of each path point in the first direction distribution map and its corresponding laying direction vector are mapped to the initial finite volume element to obtain the finite volume element.

6. The composite material fiber orientation simulation modeling method according to claim 1, characterized in that, Step S4, which characterizes the spatial distribution relationship between the principal and secondary fiber directions, includes: By adjusting the angle between the direction vectors, the direction vectors of all path points within a finite volume element are adjusted to obtain the set of adjusted direction vectors. Calculate the covariance matrix of the adjusted direction vector set, and decompose the eigenvalues ​​and corresponding eigenvectors of the covariance matrix. Take the eigenvector corresponding to the largest eigenvalue as the fiber principal direction vector, and take the eigenvector corresponding to the second largest eigenvalue as the fiber secondary direction vector. By integrating the fiber direction vectors of the primary and secondary directions, a second direction distribution map is obtained.

7. The composite material fiber orientation simulation modeling method according to claim 1, characterized in that, Step S5 includes: Step S51: Using the fiber principal direction vector corresponding to each finite volume unit in the second directional distribution diagram as the principal axis direction, and the fiber secondary direction vector orthogonal to the principal axis direction as the lateral reference direction, construct the local coordinate system of each finite volume unit; Step S52: Map the principal axis direction and transverse reference direction in the local coordinate system of each finite volume element to the preset mechanical and transverse properties of the material anisotropy, and construct a third anisotropic distribution map. Step S53: Input the third anisotropic distribution diagram into the preset finite element model to perform composite material mechanical simulation and obtain the anisotropic response results; Step S54: Compare the attribute difference values ​​of the material anisotropic properties and the anisotropic response results to obtain the fiber orientation simulation results; if the attribute difference value of the fiber orientation simulation results is greater than the preset difference value threshold, then adjust the perturbation sensitivity coefficient according to the attribute difference value gradient to update the angle adjustment of the orientation vector, and then iteratively execute steps S4 to S5 until the attribute difference value is less than the preset difference value threshold; if the attribute difference value of the fiber orientation simulation results is less than the difference value threshold, then the second orientation distribution map is the actual fiber orientation distribution map of the composite material component.

8. A simulation modeling system for fiber orientation of composite materials, characterized in that, For executing the composite material fiber orientation simulation modeling method as described in claim 1, the composite material fiber orientation simulation modeling system includes: The trajectory acquisition module is used to acquire the fiber placement trajectory through the process control interface connected to the automatic fiber placement equipment; based on the fitting error of the fiber placement trajectory on the curved surface of the component, the bending radius and unit tangent direction of the path points are corrected to obtain the fiber placement correction trajectory; The tangent direction mapping module is used to map the tangent direction of each path point in the fiber laying correction trajectory to the tangent base of the preset molding component CAD model surface to construct a first direction distribution map; The angle adjustment calculation module is used to analyze the coverage of each path on the component surface in the first direction distribution map, identify the overlapping and intersecting areas of the surface; calculate the fiber disturbance offset amplitude in the normal direction of each layer in the overlapping and intersecting areas of the surface, and calculate the angle adjustment of the direction vector based on the fiber disturbance offset amplitude and the path intersection angle of the overlapping and intersecting areas of the surface. The primary and secondary direction division module is used to divide the first direction distribution map into finite volume units. The spatial distribution trend of the fiber primary direction vector and the fiber secondary direction vector is characterized by the adjustment of the angle between the direction vectors in the corresponding finite volume units, so as to obtain the second direction distribution map. The simulation module is used to take the fiber principal direction vector of the second direction distribution map as the principal axis direction and the fiber secondary direction vector as the transverse reference direction orthogonal to the principal axis, and perform fiber direction simulation verification in combination with the preset material anisotropy properties, so as to obtain the fiber direction simulation results.

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