Non-developable curved surface FSS radome modeling method based on stamping simulation

Abstract

The invention provides a non-developable curved surface FSS radome modeling method based on stamping simulation. The method comprises the following steps that a to-be-stamped plane plate material model and a stamping die model of a radome are established; stamping simulation is conducted on the plane plate material model, and a radome grid model is obtained; according to the position, corresponding to the radar cover curved surface, on the stamping die, the corresponding position of the radar cover curved surface on the stamped plate is determined; obtaining a corresponding area of the curved surface of the radome on the plate before stamping according to the mapping relation; an FSS unit is arranged in the area, corresponding to the curved surface of the radome, of the surface plate material before stamping; and according to the mapping relationship, mapping the FSS units on the surface plate material before stamping to the curved surface of the radome after stamping to obtain a three-dimensional model of the curved surface FSS radome. According to the method, mapping between the curved surface radome after stamping and the surface plate material before stamping is established according to the stamping deformation principle, excessive deformation cannot be generated in the process that the FSS structure is transferred to the curved surface from the plane, and the modeling accuracy of the non-developable curved surface FSS radome can be guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of curved surface FSS radome modeling, and in particular to a non-developable curved surface FSS radome modeling method based on stamping simulation. Background Art

[0002] With the development of radar technology, the demand for stealth of military aircraft has become increasingly prominent. Most military aircraft, such as fighter jets, have three major radar scattering sources, namely the radar cabin, cockpit and air inlet. Among them, the radar cabin has a large radar cross section (RCS) due to the cavity scattering effect. Since the radar antenna in the radar cabin has the function of transmitting electromagnetic waves, a spatial filter is required to play the role of transmission within the antenna working frequency band and cut off outside the antenna working frequency band. Frequency Selective Surface (FSS) is such a spatial filter. It acts on the nose radar cover with a low RCS shape to scatter out-of-band waves to other directions, thereby reducing the single-station RCS of the radar cabin. However, for airborne frequency selective radomes, there are still some difficult problems to solve, the first of which is the modeling method and preparation process.

[0003] There are many difficulties in the design and preparation of curved FSS radomes. From the perspective of design and modeling, FSS units face the problem of tangential and normal deformation on the curved surface, which becomes more prominent as the unit scale decreases. From the perspective of preparation, conventional preparation methods include mechanical etching, laser etching, flexible film transfer, 3D printing, etc. Compared with flat multilayer FSS radomes, the preparation difficulty of curved multilayer FSS radomes is significantly increased: due to the existence of curvature, the preparation, surface metallization and etching of curved composite materials are greatly increased.

[0004] The Chinese patent with publication number CN108268696A discloses a method for modeling a frequency-selective radome, which first requires obtaining the parameters of the radome body and the passive resonant unit of the FSS structure, then constructing a planar FSS array model, and finally establishing a frequency-selective radome after passing through the plane. Since this method uses a plane projection method, when the curvature of the surface changes greatly, the frequency-selective structure on the FSS radome will undergo a huge deformation, thereby reducing the accuracy of the FSS radome modeling. Summary of the invention

[0005] The present invention proposes a method for modeling a non-developable surface FSS radome based on stamping simulation, which solves the problem in the prior art that when the curvature of the surface changes greatly, the frequency selective structure on the FSS radome will undergo huge deformation, thereby reducing the accuracy of FSS radome modeling.

[0006] The technical solution of the present invention is achieved in this way:

[0007] A first aspect of the present invention provides a method for modeling a non-developable surface FSS radome based on stamping simulation, comprising the following steps:

[0008] In the 3D modeling software, a flat sheet model to be punched and a punching die model of the radome are respectively established;

[0009] The stamping die model is used in the finite element simulation software to perform stamping simulation on the plane sheet metal model to obtain the grid model of the radome after stamping;

[0010] Determine the corresponding position of the radome curved surface on the sheet material after stamping according to the position of the corresponding radome curved surface on the stamping die;

[0011] According to the mapping relationship of the corresponding points on the sheet metal grid before and after stamping, the corresponding area of ​​the radome surface on the sheet metal before stamping is obtained;

[0012] Arrange the FSS unit on the area corresponding to the curved surface of the radome on the flat sheet before stamping;

[0013] According to the mapping relationship between the corresponding points on the sheet metal grid before and after stamping, the FSS units on the flat sheet metal before stamping are mapped to the curved surface of the radome after stamping to obtain the three-dimensional model of the curved FSS radome.

[0014] Specifically, the stamping die includes a pressing plate and several levels of dies, each level of the dies includes a corresponding upper die and a lower die, the pressing plate is used to cooperate with the lower die to fix the sheet material, and the curvature radius of the radome curved surface area corresponding to the upper level die is greater than the curvature radius of the radome curved surface area corresponding to the lower level die.

[0015] Furthermore, the method for performing stamping simulation on the plane sheet metal model comprises the following steps:

[0016] In the finite element simulation software, the properties of the dies and the press plate at each level are set as rigid bodies, and the properties of the sheet metal are set as deformable bodies;

[0017] Divide the triangular mesh on the sheet and each level of mold;

[0018] The sheet metal is subjected to multi-stage stamping using molds of each level in conjunction with a press plate to obtain a radome mesh model after stamping simulation.

[0019] Specifically, after obtaining the radome mesh model after stamping, it is necessary to judge whether the current radome mesh model is qualified according to the line distortion rate of the corresponding triangular mesh units on the sheet before and after stamping. The calculation formula of the line distortion rate is as follows:

[0020]

[0021] Among them, the line distortion rate ξ represents the mean value of the deformation of the three edges in the triangular mesh, l1, l2, and l3 represent the lengths of the three edges of the triangular mesh unit, and |Δl1|, |Δl2|, and |Δl3| represent the absolute values ​​of the deformation of the three edges of the triangular mesh unit;

[0022] When the line distortion rate ξ>10%, it means that the current radome grid model is unqualified.

[0023] Specifically, the method for determining the corresponding position of the radome surface on the sheet after stamping is: projecting the grid nodes corresponding to the radome surface on the mold onto the sheet after stamping along the normal direction of the sheet unit.

[0024] Specifically, the method for obtaining the corresponding area of ​​the radar cover surface on the sheet before stamping is: according to the mapping relationship between the grid nodes on the sheet before and after stamping, traverse the sheet before stamping to find the grid nodes of the radar cover surface area corresponding to the sheet after stamping.

[0025] Specifically, the method of mapping the FSS unit on the flat sheet before stamping to the radome curved surface after stamping includes:

[0026] Point M is the grid unit ΔV of the FSS unit area corresponding to the flat sheet before stamping i V j V k If a point in is a point, the coordinates of point M are expressed as:

[0027]

[0028]

[0029] in, They represent the coordinates of the three nodes of the triangular mesh unit where the point M is located; Respectively represent the point M to the edge V j V k 、V i V k 、V i V j The vertical distance Represents the edge V j V k 、V i V k 、V i V j The corresponding height;

[0030] Then point M is mapped to the grid unit ΔP of the sheet metal after stamping i P j P k The coordinates of the mapping point T in are expressed as:

[0031]

[0032] in, They represent the coordinates of the three nodes of the triangular mesh unit where point T is located;

[0033] The above mapping formula is used to map the single-layer FSS unit without thickness from the flat sheet model before stamping to the non-developable surface of the radome model after stamping, and the three-dimensional model of the curved FSS radome is obtained.

[0034] Furthermore, if the FSS unit is a multi-layer three-dimensional structure, it is necessary to extend the FSS unit in thickness. The specific method is as follows:

[0035] Point Q is the grid unit ΔV of the FSS unit area corresponding to the flat sheet before stamping i V j V k The coordinates of point Q are decomposed into two parts: normal and tangent, which are expressed as:

[0036]

[0037] in, is the normal coordinate of point Q, t is the thickness value corresponding to point Q, is the unit normal vector of the grid plane where point Q is located; represents the tangential coordinate of point Q;

[0038] Then point Q is mapped to the grid unit ΔP of the sheet metal after stamping i P j P k The coordinates of the mapping point R in are expressed as:

[0039]

[0040] in, is the unit normal vector of the grid plane where point T is located;

[0041] The mapping formula is used to map the thick multilayer FSS unit from the plane sheet model before stamping to the non-developable surface of the radome model after stamping, and the three-dimensional model of the curved FSS radome is obtained.

[0042] A second aspect of the present invention provides an electronic device, comprising a memory and a processor, wherein the memory stores a computer program that can be run on the processor, and when the processor executes the computer program, the steps of the above-mentioned non-developable surface FSS radome modeling method are implemented.

[0043] A third aspect of the present invention provides a computer-readable storage medium, wherein the storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the above-mentioned non-developable surface FSS radome modeling method are implemented.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] (1) The present invention uses the principle of stamping deformation to establish a mapping between the curved radome after stamping and the flat sheet before stamping, thereby transferring the periodic FSS pattern on the flat sheet to the curved radome. The stamping die model can be designed for any common shape of complex curved radome. In theory, the FSS periodic structure can be arranged on a radome of any shape to obtain a curved radome equipped with the FSS.

[0046] (2) The present invention can establish a model of a curved radome loaded with a precision FSS unit. Since the distortion between the sheet material structure mapping before and after stamping is very small, the precision FSS structure will not produce excessive deformation during the transfer from the plane to the curved surface, which can ensure the accuracy of modeling the non-developable curved FSS radome. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0048] Figure 1 It is a flow chart of a method for modeling a non-developable surface FSS radome based on stamping simulation according to the present invention;

[0049] Figure 2 A schematic diagram of a model of sheet materials, a press plate and various levels of stamping dies designed for the upper and lower surfaces of the radome in an embodiment of the present invention;

[0050] Figure 3 It is a schematic diagram of the grid of the upper and lower surface sheets of the radome before and after stamping in an embodiment of the present invention;

[0051] Figure 4 Schematic diagram of the corresponding areas of the upper and lower surfaces of the radome curved surface on the sheet material before and after stamping in an embodiment of the present invention;

[0052] Figure 5 Schematic diagram of the linear distortion rate of the radome curved surface in the corresponding area on the sheet material before and after stamping in an embodiment of the present invention; wherein, Figure 5 (a) is a schematic diagram of the linear distortion rate of the corresponding area on the upper surface of the radome before and after stamping; Figure 5(b) is a schematic diagram of the linear distortion rate of the corresponding area on the sheet material before and after stamping on the lower surface of the radome curved surface;

[0053] Figure 6 Schematic diagram of a broadband bandpass FSS model with high incident angle stability in an embodiment of the present invention;

[0054] Figure 7 Schematic diagram of the power transmission coefficient of FSS in an embodiment of the present invention; wherein, Figure 7 (a) is the power transmission coefficient of FSS for TE waves in this embodiment; Figure 7 (b) is the power transmission coefficient of FSS for TM waves in this embodiment;

[0055] Figure 8 It is a schematic diagram and a partial enlarged diagram of the FSS unit arranged on the flat sheet material before stamping in the radome curved surface mapping area in an embodiment of the present invention; wherein, Figure 8 (a) is a schematic diagram and a partial enlarged view of the FSS unit arrangement of the upper surface mapping area of ​​the radome curved surface on the flat sheet before stamping; Figure 8 (b) is a schematic diagram and a partial enlarged view of the FSS unit arrangement of the mapping area of ​​the lower surface of the radome on the flat sheet before stamping;

[0056] Fig. 9 It is a schematic diagram of the curved multi-layer FSS radome model finally obtained in an embodiment of the present invention and a partial enlarged diagram of the FSS units on the upper and lower surfaces of the radome. DETAILED DESCRIPTION

[0057] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0058] Reference Figure 1 In the first aspect of an embodiment of the present invention, a method for modeling a non-developable curved surface FSS radome based on stamping simulation is provided. A multi-level stamping die and a pressing plate are designed according to the shape of the radome. They are assembled and otherwise set in the finite element simulation software Abaqus. Stamping simulation is performed on the plane sheet in sequence according to the graded order to obtain the deformed sheet after the third-level stamping. Since the same sheet is always used during the stamping simulation process, a perfect one-to-one mapping relationship is formed between the sheet after stamping and the sheet before stamping. After determining the position of the curved radome on the sheet after stamping, its corresponding area can be directly found on the sheet before stamping. Next, it is only necessary to arrange FSS periodic units in the area to map it to the original radome surface to obtain a three-dimensional model of the curved surface FSS. Its implementation scheme includes the following steps:

[0059] In the 3D modeling software CATIA, the flat sheet model to be punched and the punching die model of the radome are respectively established;

[0060] In the finite element simulation software Abaqus, the stamping die model is used to perform stamping simulation on the plane sheet metal model to obtain the grid model of the radome after stamping.

[0061] Determine the corresponding position of the radome curved surface on the sheet material after stamping according to the position of the corresponding radome curved surface on the stamping die;

[0062] According to the mapping relationship of the corresponding points on the sheet metal grid before and after stamping, the corresponding area of ​​the radome surface on the sheet metal before stamping is obtained;

[0063] Arrange the FSS unit on the area corresponding to the curved surface of the radome on the flat sheet before stamping;

[0064] According to the mapping relationship between the corresponding points on the sheet metal grid before and after stamping, the FSS units on the flat sheet metal before stamping are mapped to the curved surface of the radome after stamping to obtain the three-dimensional model of the curved FSS radome.

[0065] The present invention can use the principle of stamping deformation to establish a mapping between the curved radome after stamping and the flat sheet before stamping while ensuring that the distortion is small enough, thereby transferring the periodic FSS pattern on the flat sheet to the curved radome. At the same time, the feasibility of plastic forming of the curved radome can be explored.

[0066] In some embodiments, since the upper and lower surfaces of the radar cover have large curvatures, a single stamping is difficult to meet the requirement of minimizing deformation. Therefore, this embodiment adopts a three-level stamping simulation (in the specific implementation process, the number of stamping simulations can be reduced or increased depending on the situation).

[0067] In this embodiment, Figure 2 As shown, the stamping die includes a pressing plate and a three-level die. The stamping die should be designed according to the shapes of the upper and lower surfaces of the radome. The design sequence is the third-level die → the second-level die → the first-level die. Each level of the die includes a corresponding upper die and a lower die. The pressing plate is used to cooperate with the lower die to fix the sheet material. The curvature radius of the upper-level die corresponding to the curved surface area of ​​the radome is greater than the curvature radius of the lower-level die corresponding to the curved surface area of ​​the radome.

[0068] The third-level lower mold design method in the embodiment of the present invention is to perform appropriate extrapolation and extension operations around the surface of the radar cover in the CATIA software, arrange areas on both sides of the radar cover for the pressing plate to press down, and set appropriately sized fillets at the joints to reduce the deformation of the sheet metal at the edges; the third-level upper mold is the main part of the lower mold minus the thickness of the sheet metal.

[0069] In the embodiment of the present invention, the second-level lower mold is a curved surface with a smaller curvature obtained on the basis of the third-level lower mold, and the fillets and plane areas on both sides remain unchanged. Similarly, the second-level lower mold and the first-level upper and lower molds can be obtained.

[0070] In order to maintain consistency during the stamping process, the upper and lower plane sheets have the same shape, both of which are flat plates with curved trapezoidal edges, and the upper and lower three-level stamping simulation systems share a set of press plates. The schematic diagram of the upper and lower surfaces of the radome, the sheet shape, the press plate shape and the molds at each level in the embodiment of the present invention is shown in the figure.

[0071] Furthermore, the method for performing stamping simulation on the plane sheet metal model comprises the following steps:

[0072] Import the plane sheet, various levels of dies and the blank holder into the finite element simulation software Abaqus and assemble them in sequence. The properties of various levels of dies and the blank holder are set as rigid bodies, and only the properties of the sheet are set as deformable bodies.

[0073] Apply fixed constraints to the lower die and the pressure plate, and move the upper die to a position above the sheet without contacting it. Divide the sheet and the die into grids, where the sheet is discretized as follows: Figure 3 The 5mm sized triangle mesh shown;

[0074] The upper die is moved downward to deform the sheet material until the upper surface of the sheet material coincides with the lower surface of the upper die, and the lower surface of the sheet material coincides with the upper surface of the lower die, thereby obtaining the sheet material after the first stage of stamping.

[0075] The sheet metal after the first stamping deformation is assembled in the second-level mold system, and the sheet metal after the second-level stamping forming is assembled in the third-level mold system. Finally, the sheet metal after three stamping simulations can be obtained, such as Figure 3 shown.

[0076] Specifically, the method for determining the corresponding position of the radome surface on the sheet after stamping is: projecting the grid nodes corresponding to the radome surface on the third-level die onto the sheet after stamping along the normal direction of the sheet unit, such as Figure 4 As shown, since the shape of the sheet metal after three stampings is very close to that of the die, the projected part can be approximately regarded as the surface of the radome.

[0077] Specifically, the method for obtaining the corresponding area of ​​the radar cover surface on the sheet before stamping is: according to the mapping relationship between the grid nodes on the sheet before and after stamping, traverse the sheet before stamping to find the grid nodes of the radar cover surface area corresponding to the sheet after stamping.

[0078] In this embodiment, since the same sheet metal is used throughout the stamping simulation process, any point in the plane sheet metal mesh before stamping can be mapped to the space triangle of the sheet metal after stamping through the corresponding relationship between the points on the triangle. Since all geometric features are based on points, this process actually establishes a set of perfect mapping relationships between the sheet metal before and after stamping. This perfect mapping can find the corresponding area of ​​the radome surface on the plane sheet metal, such as Figure 4 shown.

[0079] After obtaining the radome mesh model after stamping, it is necessary to judge whether the current radome mesh model is qualified according to the line distortion rate of the corresponding triangular mesh units on the sheet before and after stamping. The calculation formula of the line distortion rate is as follows:

[0080]

[0081] Among them, the line distortion rate ξ represents the mean value of the deformation of the three edges in the triangular mesh, l1, l2, and l3 represent the lengths of the three edges of the triangular mesh unit, and |Δl1|, |Δl2|, and |Δl3| represent the absolute values ​​of the deformation of the three edges of the triangular mesh unit;

[0082] When the line distortion rate ξ>10%, it means that the current radome mesh model is unqualified and needs to be remodeled and stamped.

[0083] The line distortion rate of the triangular mesh on the upper and lower surfaces of the radome before and after stamping in the embodiment of the invention is as follows: Figure 5 As shown, it can be seen that the line distortion rate in most areas is less than 3%, and only the line distortion rate at about 1 / 10 of the front end exceeds 3%. Only a few units have a relatively large line distortion rate, reaching about 6-7%, but it is still within a very small range. This shows that the deformation of most FSS units in this embodiment is very small, and only a few units have a large degree of deformation, but it is far from affecting the performance of the entire radome.

[0084] Specifically, the method of arranging the FSS unit in the corresponding area of ​​the surface of the sheet metal radome before stamping is as follows:

[0085] The embodiment of the present invention designs a bandpass FSS with high incident angle stability and wide bandwidth, such as Figure 6 As shown, Figure 6 The figure on the left side is a schematic diagram of the three-dimensional structure of the bandpass FSS of this embodiment. Figure 6 The middle figure is a schematic diagram of the internal hierarchical structure of the bandpass FSS of this embodiment. Figure 6The two figures on the right side of the figure respectively represent the structural schematic diagrams of the two-layer FSS; the FSS structure consists of two layers of FSS and three dielectric materials, namely polyetheretherketone (PEEK), Nomex aramid paper honeycomb and Teflon (also known as polytetrafluoroethylene, PTFE). The dielectric constants of PEEK, aramid paper honeycomb and Teflon are 3.4, 1.1 and 2.2, respectively, and the dielectric losses are 0.001, 0.005 and 0.0009, respectively. The material of the FSS pattern is a metal copper film, with a period of P1 = 6mm, an outer edge length of the upper inner ring P2 = 4mm, and an upper line width of w1 = w2 = 3mm; the line width of the lower square ring is w3 = 0.5mm, the line length of the internal cross pattern is l = 4.5mm, and the line width is w4 = 0.3mm; the thickness of PEEK is h1 = 1.1mm, the thickness of the aramid paper honeycomb is h2 = 1.7mm, and the thickness of Teflon is h3 = 6mm. The FSS has excellent angular stability, such as Figure 7 As shown, the FSS of this embodiment can have a power transmission coefficient greater than -1 dB in a 2 GHz bandwidth near the X-band within an incident angle of 0 to 60 degrees.

[0086] Arrange the above FSS in Figure 4 The upper and lower surfaces of the radome are in the corresponding area on the flat sheet. The effect is as follows Figure 8 shown.

[0087] Specifically, the method of mapping the FSS unit on the flat sheet before stamping to the radome curved surface after stamping includes:

[0088] The present invention establishes a perfect mapping between the sheet materials before and after stamping, and according to this mapping relationship, the FSS of the radome surface in the corresponding area of ​​the flat sheet material before stamping can be transferred to the radome surface after stamping.

[0089] Point M is the grid unit ΔV of the FSS unit area corresponding to the flat sheet before stamping i V j V k If a point in is a point, the coordinates of point M are expressed as:

[0090]

[0091] in, They represent the coordinates of the three nodes of the triangular mesh unit where the point M is located; Respectively represent the point M to the edge V j V k 、V i V k 、V i V j The vertical distance Represents the edge V j Vk 、V i V k 、V i V j The corresponding height;

[0092] Then point M is mapped to the grid unit ΔP of the sheet metal after stamping i P j P k The coordinates of the mapping point T in are expressed as:

[0093]

[0094] in, They represent the coordinates of the three nodes of the triangular mesh unit where point T is located;

[0095] The above mapping formula is used to map the single-layer FSS unit without thickness from the flat sheet model before stamping to the non-developable surface of the radome model after stamping, and the three-dimensional model of the curved FSS radome is obtained.

[0096] Furthermore, if the FSS unit is a multi-layer three-dimensional structure, it is necessary to extend the FSS unit in thickness. The specific method is as follows:

[0097] Point Q is the grid unit ΔV of the FSS unit area corresponding to the flat sheet before stamping i V j V k The coordinates of point Q are decomposed into two parts: normal and tangent, which are expressed as:

[0098]

[0099] in, is the normal coordinate of point Q, t is the thickness value corresponding to point Q, is the unit normal vector of the grid plane where point Q is located; represents the tangential coordinate of point Q;

[0100] Then point Q is mapped to the grid unit ΔP of the sheet metal after stamping i P j P k The coordinates of the mapping point R in are expressed as:

[0101]

[0102] in, is the unit normal vector of the grid plane where point T is located, which is ΔP i P j P k The arithmetic mean of the node normal vectors. The node normal vector is the arithmetic mean of the normal vectors of all triangles surrounding the node.

[0103] The mapping formula is used to map the thick multilayer FSS unit from the plane sheet model before stamping to the non-developable surface of the radome model after stamping, and the three-dimensional model of the curved FSS radome is obtained.

[0104] The above is the process of determining the coordinates of point R from point M in the order of point M→Q→T→R. Since M can be any point on the discrete thick plane, the process actually establishes a perfect mapping from a plane with thickness to a curved surface with thickness.

[0105] In theory, both planar multi-layer and three-dimensional frequency selective structures can be mapped one by one onto the non-developable radome surface, while any fine topological structure inside can be preserved.

[0106] The above process can convert the FSS unit designed in the embodiment of the present invention from Figure 8 The flat sheet shown is transferred to Fig. 9 On the radome surface shown in the figure, the non-developable surface FSS radome model is obtained. Fig. 9 The FSS arrangement effect in the area with large distortion is magnified, and it is difficult to see obvious distortion with the naked eye, which proves that the modeling method described in this paper has high accuracy.

[0107] A second aspect of an embodiment of the present invention provides an electronic device, including a memory and a processor, wherein the memory stores a computer program that can be run on the processor, and when the processor executes the computer program, the steps of the above-mentioned non-developable surface FSS radome modeling method are implemented.

[0108] A third aspect of an embodiment of the present invention provides a computer-readable storage medium, wherein the storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the above-mentioned non-developable surface FSS radome modeling method are implemented.

[0109] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A non-developable surface FSS radome modeling method based on stamping simulation, characterized in that: The following steps are involved: In the 3D modeling software, a flat sheet model to be punched and a punching die model of the radome are respectively established; The stamping die model is used in the finite element simulation software to perform stamping simulation on the plane sheet metal model to obtain the grid model of the radome after stamping; Determine the corresponding position of the radome curved surface on the sheet material after stamping according to the position of the corresponding radome curved surface on the stamping die; According to the mapping relationship of the corresponding points on the sheet metal grid before and after stamping, the corresponding area of ​​the radome surface on the sheet metal before stamping is obtained; Arrange the FSS unit on the area corresponding to the curved surface of the radome on the flat sheet before stamping; According to the mapping relationship between the corresponding points on the sheet metal grid before and after stamping, the FSS units on the flat sheet metal before stamping are mapped to the curved surface of the radome after stamping to obtain the three-dimensional model of the curved FSS radome.

2. The non-developable surface FSS radome modeling method based on stamping simulation as claimed in claim 1 is characterized in that: The stamping die includes a pressing plate and several levels of dies, each level of the dies includes a corresponding upper die and a lower die, the pressing plate is used to cooperate with the lower die to fix the sheet material, and the curvature radius of the radome curved surface area corresponding to the upper level die is greater than the curvature radius of the radome curved surface area corresponding to the lower level die.

3. A non-developable surface FSS radome modeling method based on stamping simulation as claimed in claim 2, characterized in that: The method for stamping simulation of a flat sheet metal model comprises the following steps: In the finite element simulation software, the properties of the dies and the press plate at each level are set as rigid bodies, and the properties of the sheet metal are set as deformable bodies; Divide the triangular mesh on the sheet and each level of mold; The sheet metal is subjected to multi-stage stamping using molds of each level in conjunction with a press plate to obtain a radome mesh model after stamping simulation.

4. The non-developable surface FSS radome modeling method based on stamping simulation as claimed in claim 1 is characterized in that: After obtaining the radome mesh model after stamping, it is necessary to judge whether the current radome mesh model is qualified according to the line distortion rate of the corresponding triangular mesh units on the sheet before and after stamping. The calculation formula of the line distortion rate is as follows: Among them, the line distortion rate ξ represents the mean value of the deformation of the three edges in the triangular mesh, l1, l2, and l3 represent the lengths of the three edges of the triangular mesh unit, and |Δl1|, |Δl2|, and |Δl3| represent the absolute values ​​of the deformation of the three edges of the triangular mesh unit; When the line distortion rate ξ>10%, it means that the current radome grid model is unqualified.

5. The method for modeling a non-developable surface FSS radome based on stamping simulation as claimed in claim 1, characterized in that: The method for determining the corresponding position of the radome surface on the sheet after stamping is: projecting the grid nodes corresponding to the radome surface on the mold onto the sheet after stamping along the normal direction of the sheet unit.

6. The non-developable surface FSS radome modeling method based on stamping simulation as claimed in claim 1, characterized in that: The method for obtaining the corresponding area of ​​the radome surface on the sheet before stamping is: according to the mapping relationship between the grid nodes on the sheet before and after stamping, traverse the sheet before stamping to find the grid nodes of the radome surface area corresponding to the sheet after stamping.

7. The non-developable surface FSS radome modeling method based on stamping simulation as claimed in claim 1, characterized in that: The method of mapping the FSS unit on the flat sheet before stamping to the radome surface after stamping includes: Point M is the grid unit ΔV of the FSS unit area corresponding to the flat sheet before stamping i V j V k If a point in is a point, the coordinates of point M are expressed as: in, They represent the coordinates of the three nodes of the triangular mesh unit where the point M is located; Respectively represent the point M to the edge V j V k 、V i V k 、V i V j The vertical distance Represents the edge V j V k 、V i V k 、V i V j The corresponding height; Then point M is mapped to the grid unit ΔP of the sheet metal after stamping i P j P k The coordinates of the mapping point T in are expressed as: in, They represent the coordinates of the three nodes of the triangular mesh unit where point T is located; The above mapping formula is used to map the single-layer FSS unit without thickness from the flat sheet model before stamping to the non-developable surface of the radome model after stamping, and the three-dimensional model of the curved FSS radome is obtained.

8. The method for modeling a non-developable surface FSS radome based on stamping simulation as claimed in claim 7, characterized in that: If the FSS unit is a multi-layer three-dimensional structure, it is necessary to extend the FSS unit in thickness. The specific method is as follows: Point Q is the grid unit ΔV of the FSS unit area corresponding to the flat sheet before stamping i V j V k The coordinates of point Q are decomposed into two parts: normal and tangent, which are expressed as: in, is the normal coordinate of point Q, t is the thickness value corresponding to point Q, is the unit normal vector of the grid plane where point Q is located; represents the tangential coordinate of point Q; Then point Q is mapped to the grid unit ΔP of the sheet metal after stamping i P j P k The coordinates of the mapping point R in are expressed as: in, is the unit normal vector of the grid plane where point T is located; The mapping formula is used to map the thick multilayer FSS unit from the plane sheet model before stamping to the non-developable surface of the radome model after stamping, and the three-dimensional model of the curved FSS radome is obtained.

9. An electronic device comprising a memory and a processor, wherein the memory stores a computer program that can be run on the processor, characterized in that: When the processor executes the computer program, the steps of the method for modeling a non-developable surface FSS radome as described in any one of claims 1 to 8 are implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method for modeling a non-developable surface FSS radome as claimed in any one of claims 1 to 8 are implemented.

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