Modeling method and system for three-dimensional geometric model of aviation wing structure

Abstract

The invention belongs to the technical field of aviation design, and provides a modeling method and system for a three-dimensional geometric model of an aviation wing structure, in the iterative optimization process of a spar, a rib and a stringer in an initial model, firstly, the offset is determined, then original grid vertexes in the model are expanded in the normal direction to generate a new vertex set, and the new vertex set is subjected to iterative optimization; an offset surface topological structure is reconstructed through triangulation, when the offset surface topological structure is reconstructed, the number of grid vertexes is adjusted according to the offset so as to achieve the purpose of improving the reconstruction quality of the model, when the coordinate average value after offset is larger than or equal to the coordinate average value of the original model, the number of the grid vertexes is increased, otherwise, the number of the grid vertexes is reduced, and the reconstruction quality of the model is improved. The purpose of improving the model reconstruction speed is achieved; on the basis of ensuring the modeling efficiency, the problem that the model precision is reduced after geometric reconstruction due to insufficient grid division proportion is solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aviation design, and particularly relates to an aviation wing structure three-dimensional geometric model modeling method and system. BACKGROUND

[0002] The specific process of wing structure design is divided into two stages of sample design and detailed design. In the sample design stage, first, the elements are designed in two dimensions, then a three-dimensional geometric model is established, the main performance of the structure is evaluated through finite element analysis on the three-dimensional model, the two-dimensional layout is modified again according to the analysis results until the requirements are met. Due to the iteration and circulation of sample design, it usually takes a lot of time for the structure designer to design from two-dimensional layout design to modification to the establishment of a three-dimensional geometric model, which affects the design efficiency of the aircraft. With the development of computer-aided design (CAD) technology, the parametric modeling method has been gradually applied in design, which has improved the design efficiency to a certain extent.

[0003] The geometric parameters of key components such as ribs, spars and stringers in the wing structure need to be adjusted multiple times. When the offset surface topology structure is reconstructed in each iterative design, the surface vertex coordinates change, so if the original grid vertices are directly used as a scatter set, there is a problem of reduced model accuracy after geometric reconstruction due to insufficient grid division ratio, and too many grids will affect the modeling efficiency. In addition, the increase of curvature error caused by size change, and the process of open edge surface repair, will also affect the modeling accuracy and efficiency, etc. SUMMARY

[0004] To solve the above problems, the application provides an aviation wing structure three-dimensional geometric model modeling method and system. In the iterative optimization process of the spar, rib and stringer in the initial model, the offset is first determined, then the original grid vertices in the model are expanded along the normal direction to generate a new vertex set, and the offset surface topology structure is reconstructed through triangulation. When reconstructing the offset surface topology structure, the number of grid vertices is adjusted according to the offset to improve the quality of model reconstruction. When the average value of the offset coordinates is greater than or equal to the average value of the coordinates of the original model, the number of grid vertices is increased, otherwise the number of grid vertices is reduced to improve the speed of model reconstruction. On the basis of ensuring the modeling efficiency, the problem of reduced model accuracy after geometric reconstruction due to insufficient grid division ratio is solved.

[0005] To achieve the above purpose, the application is implemented by the following technical solutions: In a first aspect, the application provides an aviation wing structure three-dimensional geometric model modeling method, comprising: obtaining an initial model of an aviation wing; The initial model of the aircraft wing is subjected to finite element simulation, and if the finite element simulation result meets the preset requirement, the final model is obtained, otherwise, the initial model is optimized; The spar, rib and stringer in the initial model are subjected to iterative optimization design until the finite element simulation result meets the preset requirement; in the process of iterative optimization of the spar, rib and stringer in the initial model, the offset is first determined, then the original grid vertex in the model is expanded along the normal direction to generate a new vertex set, the offset surface topology is reconstructed through triangulation, when reconstructing the offset surface topology, the number of grid vertices is adjusted according to the offset, when the average value of the coordinates after offset is greater than or equal to the average value of the coordinates of the original model, the number of grid vertices is increased, otherwise, the number of grid vertices is reduced.

[0006] Further, the number of the new vertex set generated by expanding the original grid vertex along the normal direction is: ; Wherein, the number of the new vertex set generated by expanding the original grid vertex along the normal direction; the number of the original grid vertex; the average value of the coordinates after model offset; the average value of the coordinates of the original model; and is a preset coefficient.

[0007] Further, in the process of establishing and iterative optimization of the spar model, based on the spar chord plane and the beam projection line in the layout diagram, a plurality of station planes are sequentially created perpendicular to the reference plane, the plane is created on the reference plane, for the completed plane, thickening is carried out according to the thickness parameter to obtain a beam thick model; the beam thick model is segmented to obtain the beam entity in the middle of the upper and lower wing surfaces.

[0008] Further, the correctness of the created beam station plane topology structure is checked, if it does not meet the closure requirement, it is stitched; the offset calculation is carried out on all the vertices of the topology, the original grid vertex is expanded along the normal direction to generate a new vertex set, the offset surface topology is constructed through the Delaunay triangulation algorithm; the boundary ring detection method is used to traverse all the edge structures, and the edge sharing state is recorded through the hash table; the open edge detected is automatically supplemented; the space partition tree is used for rapid collision detection, and the face sheet which penetrates is subjected to local grid reconstruction; the least square method is used to optimize and adjust the vertex position, and the self-intersection is eliminated while the curvature continuity is maintained; the newly formed face is subjected to topology data splicing to create a three-dimensional entity structure.

[0009] Further, when the surface patch is generated, the tangent lines at the two ends of the open edge are made, if the two tangent lines coincide or the included angle of the tangent lines is less than a preset included angle value, then the surface is directly repaired, otherwise, an auxiliary point is added at the open end, and then the surface is repaired.

[0010] Further, when the wing rib is optimized, firstly, the single wing rib and the intersecting single wing beam are subjected to Boolean sum to obtain a single entity, then the obtained entity is segmented with the side surface at both sides of the wing beam as a reference to complete rib segmentation, and finally, each wing rib is subjected to shell extraction according to the thickness parameter to generate a hollow structure, and the wing rib creation is completed.

[0011] Further, self-intersection detection and repair are performed, the offset surface is discretized into a triangular mesh, a tree acceleration collision detection algorithm is used to detect the penetration between the meshes, and then direction control and coordinate system transformation are performed to ensure that the normal vectors of all retained surfaces point to the same side, entity reconstruction is performed, and Boolean subtraction operation is used to realize the subtraction of the body.

[0012] Further, when the longeron is created and optimized, the longeron line in the two-dimensional layout drawing is projected onto the upper and lower skin surfaces to generate a projection line, and then the projection line is swept according to the cross-sectional sketch to form a three-dimensional longeron entity.

[0013] Further, when the longeron is created and optimized, the projection point of each discrete point on the surface is calculated, and the projection points are connected to form a curve, and the entity is created based on the interface and the path.

[0014] Further, when the longeron is created and optimized, interpolation and coordinate transformation are performed, including: the path is discretized into a plurality of sampling points by uniform sampling of arc length, tangent and normal parameters of the plurality of sampling points are determined, and the cross section is placed in the local coordinate system of the sampling point.

[0015] In a second aspect, the present application further provides an aviation wing structure three-dimensional geometric model modeling system, comprising: An initial model acquisition module is configured to acquire an initial model of an aviation wing. A judgment module is configured to perform finite element simulation on the initial model of the aviation wing, if the finite element simulation result meets a preset requirement, a final model is obtained, otherwise, the initial model is optimized. The optimization module is configured to iteratively optimize the wing beam, the wing rib and the stringer in the initial model until the finite element simulation result meets the preset requirement.

[0016] In a third aspect, the present application further provides a computer readable storage medium, which has a computer program stored thereon, and the program is executed by a processor to implement the steps of the method for modeling a three-dimensional geometric model of an aerofoil structure according to the first aspect.

[0017] In a fourth aspect, the present application further provides an electronic device, which comprises a memory, a processor and a computer program stored in the memory and capable of running on the processor, and the processor implements the steps of the method for modeling a three-dimensional geometric model of an aerofoil structure according to the first aspect when executing the program.

[0018] In a fifth aspect, the present application further provides a computer program product, which comprises a computer program, and the computer program is executed by a processor to implement the steps of the method for modeling a three-dimensional geometric model of an aerofoil structure according to the first aspect.

[0019] Compared with the prior art, the present application has the following beneficial effects: In the present application, during the iterative optimization of the wing beam, the wing rib and the stringer in the initial model, the offset is first determined, then the original grid vertices in the model are expanded along the normal direction to generate a new vertex set, the offset surface topology is reconstructed through triangulation, and when the offset surface topology is reconstructed, the number of grid vertices is adjusted according to the offset, so as to improve the quality of model reconstruction, and when the average value of the offset coordinates is greater than or equal to the average value of the coordinates of the original model, the number of grid vertices is increased, otherwise, the number of grid vertices is reduced, so as to improve the speed of model reconstruction; on the basis of ensuring the modeling efficiency, the problem of reduced model accuracy after geometric reconstruction caused by insufficient grid division proportion is solved. BRIEF DESCRIPTION OF DRAWINGS

[0020] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application and are incorporated in and constitute a part of this application. The embodiments illustrated in the drawings provide one or more examples by which the present application can be practiced and serve to explain the principles of the present application.

[0021] Figure 1 The flow chart of the modeling method of the first embodiment of the present application; Figure 2 Flowchart for modeling of embodiment 1 of the present application; Figure 3 Flowchart for drawing wing main frame structure layout of embodiment 1 of the present application; Figure 4 Drawing effect of wing main frame structure layout of embodiment 1 of the present application; Figure 5 Flowchart for creating spar of embodiment 1 of the present application; Figure 6 Flowchart for creating thickening of embodiment 1 of the present application; Figure 7 Tangent line diagram of open edge two ends of embodiment 1 of the present application; Figure 8 Tangent line angle diagram of embodiment 1 of the present application; Figure 9 Auxiliary point diagram of embodiment 1 of the present application; Figure 10 Spar creation effect diagram of embodiment 1 of the present application; Figure 11 Flowchart for creating wing rib rough model of embodiment 1 of the present application; Figure 12 Flowchart for optimizing wing rib rough model of embodiment 1 of the present application; Figure 13 Wing rib creation middle split effect diagram of embodiment 1 of the present application; Figure 14 Flowchart for creating wing stringer of embodiment 1 of the present application; Figure 15 Flowchart for line projection to surface of embodiment 1 of the present application; Figure 16 Long stringer sweep forming entity algorithm diagram of embodiment 1 of the present application; Figure 17 Three-dimensional geometric model diagram of wing structure of embodiment 1 of the present application; Figure 18 Three-dimensional geometric model diagram of wing structure with skin of embodiment 1 of the present application. DETAILED DESCRIPTION

[0022] The present application will be further described below in conjunction with the accompanying drawings and embodiments.

[0023] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs.

[0024] Embodiment 1 The embodiment provides a modeling method of a three-dimensional geometric model of an aviation wing structure, as shown in the figure, the method comprises the following steps: Figure 1 S1, acquiring an initial model of the aviation wing; wherein the initial model comprises a spar, a rib and a stringer.

[0025] S2, performing finite element simulation on the initial model of the aviation wing, if a finite element simulation result meets preset requirements, a final model is obtained, otherwise, the initial model is optimized.

[0026] S3, performing iterative optimization design on the spar, the rib and the stringer in the initial model until the finite element simulation result meets the preset requirements. In the process of performing iterative optimization on the spar, the rib and the stringer in the initial model, first, an offset amount is determined, then, original grid vertices in the model are expanded in a normal direction to generate a new vertex set, a bias surface topology structure is reconstructed through triangulation, when the bias surface topology structure is reconstructed, the number of grid vertices is adjusted according to the offset amount, when an average value of the coordinates after offset is greater than or equal to an average value of the coordinates of the original model, the number of grid vertices is increased, otherwise, the number of grid vertices is reduced.

[0027] In some embodiments, the aircraft structure is arranged based on a wing chord plane, and the main operation objects are the spar, the rib and the stringer. As shown in the figure, the overall implementation method flow comprises wing main body framework structure layout, spar creation, rib creation, stringer creation, finite element analysis on the model to evaluate the main performance of the structure, and iteration until the result meets the design requirements. Figure 2

[0028] In some embodiments, steps S1-S3 comprise the following steps: Wing main body framework structure layout: S3.1, in the embodiment, a preliminary two-dimensional layout of the wing main body structure is performed based on the wing skin and related evaluation data, mainly referring to load distribution, structural strength, aerodynamic shape, structural stiffness and the like, to generate a preliminary version of the wing main body framework structure layout. As shown in the figure, it is a drawing flow of the layout, optionally, the wing main body framework structure layout is based on the wing chord plane, and the layout lines of the spar, the rib and the stringer are drawn on the plane. Meanwhile, the reference skin surface needs to be added to the scene. Figure 3 In some embodiments, the effect of the wing main body framework structure layout is as shown in the figure, wherein the horizontal lines are the plane projection lines of the spars or the stringers, and the vertical lines are the plane projection lines of the ribs, which can be created through three-dimensional software.

[0029] Figure 4

[0030] ​​​​The projection line creation based on the wing chord plane proposed in this embodiment can dynamically modify the position and length of each projection line, and can also delete those that do not meet the requirements. It is flexible and easy to adjust.

[0031] In some embodiments, steps S2 and S3 include: S3.2 Creation of the wing spars: like Figure 5 As shown, in this embodiment, the wing spars are created automatically based on the wing's load distribution, structural strength requirements, and geometric parameters such as the spars' length, position, and thickness.

[0032] Optionally, first, based on the wing chord plane and the beam projection lines in the layout drawing, create multiple beam positioning planes perpendicular to the reference plane, with each plane perpendicular to the reference plane and tangent to the projection lines. Create planes on the reference plane, ensuring their size exceeds the maximum vertical height of the skin. For completed planes, thicken them according to thickness parameters to obtain the beam rough model. Divide the beam rough model using a reference skin surface to obtain the beam solids between the upper and lower wing surfaces. Repeat the above steps to create multiple wing spars. For example... Figure 6 As shown, the thickening process is as follows: S3.2.1 Verification and suturing of curved surfaces: Optionally, the correctness of the created beam station plane topology is checked. If it does not meet the closure requirements, it is stitched together. The number of edges of all topologies is calculated through stitching, using the following formula: Total number of edges x2 = ∑ (number of edges of all faces).

[0033] S32.2 Thickening Offset Calculation: Offset calculation is performed for all vertices of the topology, using the following formula: Left surface vertex coordinates for: ; Right surface vertex coordinates for: ; in, It is the normal vector; The initial topological vertex coordinates are used as the offset reference; For thickness.

[0034] S3.2.3 Geometric Reconstruction: The original mesh vertices are expanded along the normal direction to generate a new vertex set, and the offset surface topology is constructed using the Delaunay triangulation algorithm. Vertex stitching technology is used to process non-manifold boundaries, eliminating vertex spacing smaller than the tolerance threshold.

[0035] When reconstructing the offset surface topology, the coordinates of the surface vertices change. Therefore, directly using the original mesh vertices as the scatter set is not feasible. V, the model precision may be reduced due to insufficient grid division ratio; the problem can be solved by increasing the number of grid vertices, but too many grids will increase the calculation amount and affect the modeling efficiency; in order to balance the model precision and the modeling efficiency, in the embodiment, the number of grid vertices is adjusted according to the offset calculation amount, and optionally: ; wherein, is the number of new vertices generated by extending the original grid vertices along the normal direction; is the number of original grid vertices; is the average value of the coordinates of the model after offset, which can refer to the average value of the coordinates on a certain coordinate axis; is the average value of the coordinates of the original model; and are preset coefficients, which can be determined by experiments or the like. , it is indicated that the model size needs to be increased, and at this time, the number of grid vertices needs to be appropriately increased to improve the model reconstruction quality; , it is indicated that the model size needs to be reduced, and at this time, the number of grid vertices needs to be appropriately reduced to improve the model reconstruction speed. On the basis of ensuring the modeling efficiency, the problem of reduced model precision after geometric reconstruction due to insufficient grid division ratio is solved. In the reconstruction of the offset surface topology of the wing rib and the longeron, the above-mentioned way is still adopted, and will not be described in detail hereinafter.

[0036] In some embodiments, the preset coefficients and are determined, and a ratio is determined according to the overall width of the curved surface after offset and the original curved surface in the direction of large curvature change, and the ratio is calculated in multiple positions and the average value is taken.

[0037] In some embodiments, and are determined by experiments or the like, and can be determined by screening. For example, and take values between 0 and 1 (0 is not included), and the time used for finite element simulation steps is taken as the basis, when =1 and =0.1, the time used for simulation calculation is not much different (for example, the time difference is less than or equal to 1 minute), and can be directly set to 1; when =1 and =0.1, the time used for simulation calculation is greatly different (for example, the time difference is greater than 1 minute), and the time used for simulation calculation when =0.9 and =0.1 can be compared until takes a value and When the value is 0.1, the simulation calculation time is not significantly different, thus determining... The value of .

[0038] Similarly, based on the time taken in the finite element simulation steps, when =0.1 and When =1, the time difference in simulation calculations is not significant (e.g., the time difference is less than or equal to 1 minute). The value can be directly set to 0.1; when =0.1 and When = 1, if the time difference in simulation calculation is large (e.g., the time difference is greater than 1 minute), then the comparison can continue. =0.2 and When =1, the simulation calculation time is used until... Values ​​and When =1, the simulation calculation time is not significantly different, therefore... The value of .

[0039] It should be noted that, under some complex curved surfaces, adjusting the number of network vertices based on the average of the coordinates of all or multiple coordinate points on the coordinate axis can have a certain impact on the calculation speed and the reflection of the true situation at the vertex (increasing the amount of computation). In this embodiment, the average of the coordinates of multiple coordinate points within a certain distance from the vertex position on the coordinate axis can be selected to improve the calculation speed and reflect the true situation of the vertex.

[0040] S3.2.4 Edge-Face Consistency Check: A boundary loop detection method is used to traverse all edge structures, and the edge sharing state is recorded using a hash table. For detected open edges, patch faces are automatically generated to ensure the thickened model meets the closure requirements. Fast collision detection is performed based on a spatial partitioning tree (BVH), and local mesh reconstruction is performed on patches that have penetrated each other. The least squares method is used to optimize and adjust vertex positions, eliminating self-intersections while maintaining curvature continuity.

[0041] In some embodiments, such as Figure 7 and Figure 8 As shown, when generating the patch, tangents are drawn at both ends of the open edge. If the two tangents coincide or the included angle between the tangents is less than the preset angle value, the patch is directly generated; otherwise, as shown... Figure 9 As shown, auxiliary points are added at the open opening before surface patching. Optionally, the auxiliary points are located in the middle of the open opening. Adding auxiliary points can ensure the overall curvature of the model and maintain its accuracy.

[0042] Optionally, according to engineering practice, when a conventional model is built, the preset angle value is usually 5°-15°. The model in this embodiment is an aviation wing structure, which belongs to a special scenario of aviation wing structure and has higher precision requirements, and the preset angle value can be reduced to 1°-5°; when the angle between the two tangent lines is less than this range, the surface can be directly filled; otherwise, auxiliary points need to be added to maintain the continuity of curvature.

[0043] The preset angle value can be verified by finite element analysis of the stress distribution of the model built under different preset angles, and the value that minimizes the strain gradient is selected. Alternatively, a three-coordinate measuring instrument is used to detect the deviation of the filled surface from the original model to determine the optimal preset angle value.

[0044] S3.2.5, geometric topology splicing: the newly formed surface is topologically spliced to create a three-dimensional entity structure. For the inner and outer structures generated by offset, BSP (Binary Space Partitioning Tree) tree Boolean operation algorithm is applied. By preprocessing to exclude non-intersecting patches, the computational complexity is reduced from O(n2) to O(n log n).

[0045] The thickening algorithm process above maintains the geometric characteristics of the original model, reduces the curvature error, and improves the accuracy of the closed topology section.

[0046] The segmentation algorithm mentioned in the above process is as follows: S3.2.6, determine the intersection line of the segmented surface and the entity by Boolean operation to generate an accurate intersection boundary. At the same time, refer to the parametric surface subdivision technique to perform mesh densification in the contact area of the segmented surface domain entity to maintain curvature continuity.

[0047] S3.2.7, according to the intersection line, the original entity is divided into multiple sub-domains, and the edge surface topology relationship of the sub-domains to be retained is reconstructed. The open boundary after segmentation is stitched with vertices, and the mesh structure of the cut region is reconstructed using local triangulation to ensure the closure of the non-popular boundary.

[0048] Through the accuracy of the segmentation algorithm based on Boolean operation, it is ensured that the upper and lower surfaces of the segmented entity meet the continuity of the high-order skin surface, and the accuracy is higher.

[0049] As shown in Figure 10 , the top and bottom of the spar are created in this embodiment to meet the requirement of completely fitting the high-precision skin surface, making the subsequent finite element analysis more accurate.

[0050] S3.3, creation of wing ribs: Optionally, according to the aerodynamic shape and structural requirements of the wing, the geometric parameters of the wing ribs, such as thickness, are defined. As shown in Figure 11 ​As shown, first create a thick rib model, then perform rib segmentation, shell optimization, and create multiple position rib sub-rib.

[0051] S3.3.1, first create multiple rib station planes perpendicular to the reference plane based on the wing chord plane and rib projection line in the layout diagram. The plane is perpendicular to the reference plane and cuts through the projection line. Create the plane on the reference plane, and the plane size needs to exceed the upper and lower highest height of the skin. For the completed plane, thicken according to the thickness parameter to obtain the wing rib thick model. For the wing rib thick model, perform segmentation by referring to the skin surface to obtain the wing rib entity in the upper and lower wing surfaces; repeat the above content to create multiple wing rib thick models.

[0052] S3.3.2, for the created wing rib thick model, optimization is needed. As shown, Figure 12 The wing rib optimization process includes: S3.3.2.1, first perform Boolean sum on a single wing rib and a single wing spar intersecting with it to obtain a single entity; then divide the entity obtained in the last step by taking the side surface on both sides of the wing spar as the reference to complete rib segmentation. According to the above operation, perform Boolean sum and segmentation on all places where the wing rib and the wing spar intersect. Finally, generate a hollow structure by individually shell-extracting each wing rib according to the thickness parameter, complete the wing rib creation, and the effect is as shown in Figure 13 The thickening, reconstruction, and segmented entity algorithms used in the wing rib thick model creation process have the same core algorithm as the thickening, reconstruction, and segmented entity algorithms in the wing spar creation, and will not be described in detail here.

[0053] Optionally, the Boolean sum algorithm in the wing rib optimization process is based on the BSP tree algorithm, which can effectively control the data rendering order, realize rendering from back to front, and ensure correct visibility and rendering effect. The segmented entity algorithm in the wing rib optimization process differs from the wing spar creation in that the entities on both sides of the segmented surface are retained. The shell-extraction algorithm in the wing rib optimization process needs to generate a bias surface first, offset a fixed distance along the normal vector direction according to the uniform thickness bias, and mainly includes plane and surface bias: Plane: translate the vertex coordinates as follows: ax + by + cz +( d ± t ) = 0; Wherein, a is the normal vector of the plane equation x direction component, x is the x variable; b is the normal vector of the plane equation y direction component,y for y To the variable; c Let z be the z-direction component of the normal vector of the plane equation. z for z To the variable; d The translation constant of the plane equation; t Let be the translational offset of the plane along the normal vector, when t When >0, the plane moves in the opposite direction to the normal vector. t When <0, the plane moves in the positive direction of the normal vector.

[0054] Surface: For a parametric surface, sample points are discretely defined by the normal vector, and the surface is refitted after point-by-point offset. For parameters ( u , v ) surface points S ( u , v Its offset point is: S '( u , v )= S ( u , v )+ · N ( u , v ); in, u Variables representing the horizontal dimension of the surface; v Variables representing the longitudinal dimension of the surface; The variable parameter represents the distance offset along the normal vector of the current position point; N It is the unit normal vector.

[0055] S3.3.2.2 Perform self-intersection detection and repair, discretize the offset surface into a triangular mesh, and use the AABB tree to accelerate the collision detection algorithm to detect penetration between meshes, improving detection efficiency. Then perform orientation control and coordinate system transformation to ensure that the normal vectors of all retained surfaces point to the same side.

[0056] S3.3.2.3 Finally, the entity is reconstructed using Boolean subtraction to perform the subtraction of the entity. This is implemented using a basic geometric algorithm based on a 3D software platform.

[0057] The rib creation implemented in this embodiment ensures a precise match between the internal cavity and the external geometry, and its boundaries better meet the requirements of the design data. The result is accurate, eliminating the need for multiple complex positioning operations and improving design efficiency.

[0058] S3.4, Long Truss Creation: S3.4.1, such as Figure 14As shown, according to the skin support and structural stiffness requirements of the wing, based on the wing root plane coordinate system, the cross-sectional shape and width, height parameters and other stringer geometric parameters are defined, the cross-sectional sketch is created according to the parameters, then the stringer line in the two-dimensional layout drawing is projected onto the upper and lower skin surfaces to generate a projection line. Then, according to the cross-sectional sketch and the projection line, the stringer three-dimensional entity is created by sweeping. The above operations are sequentially performed on each stringer to complete the creation of the wing stringer.

[0059] S3.4.2, the projection process of the stringer line in the two-dimensional layout drawing onto the upper and lower skin surfaces is as shown in Figure 15

[0060] Curve: C(t) = (x 0 + • dx, y 0 + • dy, z 0 + • dz), t e [0, 1] ; wherein, C ( t ) is a curve equation; is a parameter variable, representing the linear interpolation of the curve from the starting point to the ending point, and the value range is 0 to 1; x 0 is the offset of the curve in the x direction; dx is the x component of the direction vector from the starting point to the ending point; y 0 is the offset of the curve in the offset in the y direction ; dy is the y component of the direction vector from the starting point to the ending point; z 0 is the offset of the curve in the z direction; dz is the z component of the direction vector from the starting point to the ending point.

[0061] The surface is defined as z = f ( x , y ); the discrete step is △t , and the control accuracy is P i ( X i , Y i , Z i ), wherein, P i is the step point of the two-dimensional layout curve;​X i the step point x value; Y i the step point y value; Z i the step point z value.

[0062] For each discrete point P i calculate its projection point on the surface, the formula is Q i ( X i , Y i , f ( X i , Y i ) connect the intersection points to form a curve.

[0063] S3.4.3, the interface and path-based creation entity algorithm flow as shown in Figure 16 ; when defining the cross section, according to the cross section type, such as T type, define its width, thickness and height, draw the cross section. Assuming that the two-dimensional cross section is C ( u ), u ∈[0,1], assuming the parameter line is P ( t ), t ∈[0,1].

[0064] S3.4.4, interpolation and coordinate transformation implementation: S3.4.4.1, using arc length uniform sampling, the path P ( t ) is discretized into n sampling points, P 0, P 1,… P n}.

[0065] S3.4.4.2, find the tangent n i and normal T i parameters of the N sampling points.

[0066] S3.4.4.3, put the cross section into the local coordinate system of the sampling point, according to the initial cross section calculation: C i ​u P i M i C u M i is a rotation scale matrix in a local coordinate system.

[0067] The grid generation and topological stitching refer to the geometric reconstruction, edge surface consistency check and topological splicing in beam creation, that is, the creation of the long string entity.

[0068] The long string created by the embodiment can completely fit the wing skin on the upper surface of the long string, the path is free, and the accuracy is high.

[0069] As shown in Figure 17 and Figure 18 , according to the embodiment, the spar, rib and long string creation of the wing structure three-dimensional geometric model can be efficiently and flexibly completed, the skeleton position is controlled based on the two-dimensional drawing, and the three-dimensional model is created, which provides a new idea for the wing structure design of the aircraft.

[0070] The embodiment combines a three-dimensional software platform to perform three-dimensional modeling of the wing main frame structure, supports structure creation after main parameters are determined, and iteratively and quickly modifies, thereby significantly improving the wing main modeling efficiency and accuracy, and realizing rapid sample design.

[0071] Embodiment 2 The embodiment provides a three-dimensional geometric model modeling system of an aircraft wing structure, including: An initial model acquisition module configured to acquire an initial model of an aircraft wing; A judgment module configured to perform finite element simulation on the initial model of the aircraft wing, and if the finite element simulation result meets the preset requirement, a final model is obtained, otherwise, the initial model is optimized; An optimization module configured to perform iterative optimization design on the spars, ribs and long strings in the initial model until the finite element simulation result meets the preset requirement; wherein, in the iterative optimization process of the spars, ribs and long strings in the initial model, first, the offset is determined, then the original grid vertex in the model is expanded to generate a new vertex set along the normal direction, the offset surface topological structure is reconstructed by triangulation, when reconstructing the offset surface topological structure, the number of grid vertices is adjusted according to the offset, when the average value of the offset coordinates is greater than or equal to the average value of the coordinates of the original model, the number of grid vertices is increased, otherwise, the number of grid vertices is reduced.

[0072] The working method of the system is the same as the three-dimensional geometric model modeling method of the aircraft wing structure in embodiment 1, which will not be repeated here.​​​​​​

[0073] Embodiment 3: The embodiment provides a computer readable storage medium, which stores a computer program, and the program is executed by a processor to realize steps of the modeling method of the three-dimensional geometric model of the aviation wing structure in the embodiment 1.

[0074] Embodiment 4: The embodiment provides an electronic device, which comprises a memory, a processor and a computer program stored in the memory and capable of running on the processor, and the processor realizes steps of the modeling method of the three-dimensional geometric model of the aviation wing structure in the embodiment 1 when executing the program.

[0075] Embodiment 5: The embodiment provides a computer program product, which comprises a computer program, and the computer program is executed by a processor to realize steps of the modeling method of the three-dimensional geometric model of the aviation wing structure in the embodiment 1.

[0076] The above merely provides preferred embodiments of the embodiment and is not intended to limit the embodiment. The embodiment can have various modifications and changes for those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the embodiment shall be included in the protection scope of the embodiment.

Claims

1. A method for modeling a three-dimensional geometric model of an aircraft wing structure, characterized in that, include: Obtain the initial model of the aircraft wing; Finite element simulation is performed on the initial model of the aircraft wing. If the finite element simulation results meet the preset requirements, the final model is obtained; otherwise, the initial model is optimized. The wing spars, ribs, and stringers in the initial model are iteratively optimized until the finite element simulation results meet the preset requirements. In the iterative optimization process of the wing spars, ribs, and stringers in the initial model, the offset is first determined, and then the original mesh vertices in the model are expanded along the normal direction to generate a new vertex set. The offset surface topology is reconstructed by triangulation. When reconstructing the offset surface topology, the number of mesh vertices is adjusted according to the offset. When the average coordinate of the offset is greater than or equal to the average coordinate of the original model, the number of mesh vertices is increased; otherwise, the number of mesh vertices is reduced.

2. The method for modeling a three-dimensional geometric model of an aircraft wing structure as described in claim 1, characterized in that, The number of new vertex sets generated by expanding the original mesh vertices along the normal direction is: ； in, The number of new vertex sets generated by expanding the original mesh vertices along the normal direction; This represents the original number of mesh vertices; The average coordinates after model offset; This represents the average coordinates of the original model; and These are preset coefficients.

3. The method for modeling a three-dimensional geometric model of an aircraft wing structure as described in claim 1, characterized in that, During the establishment and iterative optimization of the wing spars model, multiple station planes are created sequentially perpendicular to the reference plane based on the wing chord plane and the beam projection lines in the layout diagram. Planes are created on the reference plane. For the completed planes, they are thickened according to the thickness parameters to obtain the beam rough model. The beam rough model is then divided to obtain the beam entity in the middle of the upper and lower wing surfaces.

4. The method for modeling a three-dimensional geometric model of an aircraft wing structure as described in claim 3, characterized in that, The correctness of the created beam station plane topology is checked. If the closure requirement is not met, stitching is performed. Offset calculations are performed on all topological vertices. The original mesh vertices are expanded along the normal direction to generate a new vertex set. The offset plane topology is constructed using the Delaunay triangulation algorithm. All edge structures are traversed using the boundary loop detection method, and the edge sharing state is recorded using a hash table. Patch panels are automatically generated for detected open edges. Fast collision detection is performed based on spatial partitioning trees, and local mesh reconstruction is performed on the facets that have penetrated each other. The least squares method is used to optimize and adjust the vertex positions, eliminating self-intersections while maintaining curvature continuity. The newly formed faces are then stitched together with topological data to create a three-dimensional solid structure.

5. The method for modeling a three-dimensional geometric model of an aircraft wing structure as described in claim 4, characterized in that, When generating the patch, draw tangents at both ends of the open edge. If the two tangents coincide or the angle between the tangents is less than the preset angle value, then patching is performed directly; otherwise, add auxiliary points at the open opening before patching.

6. The method for modeling a three-dimensional geometric model of an aircraft wing structure as described in claim 1, characterized in that, During rib optimization, firstly, a Boolean sum is performed on a single rib and an intersecting single spar to obtain a single solid; then, the obtained solids are segmented sequentially using the sides of the spar as references to complete rib segmentation; finally, each rib is individually shelled according to the thickness parameters to generate a hollow structure, thus completing rib creation.

7. The method for modeling a three-dimensional geometric model of an aircraft wing structure as described in claim 6, characterized in that, Self-intersection detection and repair are performed by discretizing the offset surface into a triangular mesh, using a tree-accelerated collision detection algorithm to detect penetration between meshes, and then performing direction control and coordinate system transformation to ensure that the normal vectors of all retained surfaces point to the same side; solid reconstruction is performed by using solid Boolean subtraction to achieve solid subtraction; when creating and optimizing the stringer, the stringer lines in the 2D layout drawing are projected onto the upper and lower skin surfaces to generate projection lines, and then swept and created according to the cross-section sketch and projection lines to form a 3D solid stringer.

8. The method for modeling a three-dimensional geometric model of an aircraft wing structure as described in claim 7, characterized in that, When creating and optimizing the stringer, the projection point of each discrete point on the surface is calculated, the intersection points are connected to form a curve, and the entity is created based on the interface and path.

9. The method for modeling a three-dimensional geometric model of an aircraft wing structure as described in claim 8, characterized in that, When creating and optimizing the stringer, interpolation and coordinate transformation are performed, including: using uniform sampling of arc length to discretize the path into multiple sampling points, determining the tangent and normal parameters of multiple sampling points, and placing the cross section in the local coordinate system of the sampling points.

10. A three-dimensional geometric modeling system for aircraft wing structures, characterized in that, include: The initial model acquisition module is configured to acquire the initial model of an aircraft wing; The judgment module is configured to: perform finite element simulation on the initial model of the aircraft wing; if the finite element simulation results meet the preset requirements, the final model is obtained; otherwise, the initial model is optimized. The optimization module is configured to iteratively optimize the design of the wing spars, wing ribs, and stringers in the initial model until the finite element simulation results meet the preset requirements. In the iterative optimization process of the wing spars, wing ribs, and stringers in the initial model, the offset is first determined, and then the original mesh vertices in the model are expanded along the normal direction to generate a new vertex set. The offset surface topology is reconstructed through triangulation. When reconstructing the offset surface topology, the number of mesh vertices is adjusted according to the offset. When the average coordinate of the offset is greater than or equal to the average coordinate of the original model, the number of mesh vertices is increased; otherwise, the number of mesh vertices is decreased.

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