Negative Poisson's ratio ligament chiral structure lattice structure and antenna reflecting surface manufactured by same

Abstract

The invention provides a negative Poisson's ratio ligament chiral structure dot matrix structure and an antenna reflecting surface manufactured by the same, the dot matrix structure comprises a plurality of pre-folded hexa-ligament chiral cell elements which are repeatedly and regularly arranged, and each hexa-ligament chiral cell element comprises six ligaments and a circular node; the ligament is divided into a transition section, a pre-folding section and a separation section, one end of the transition section is the starting end of the ligament and used for being connected with a circular node, the other end of the transition section is connected with one end of the pre-folding section, the other end of the pre-folding section is connected with the separation section, and the other end of the separation section is used as the tail end of the ligament. The ligament connecting piece is used for being connected with the tail end of a ligament of another pre-folded hexa-ligament chiral cell. The pre-gathering section is an arc line in the concentric circle of the circular node, a machining gap exists between the pre-gathering section and the circular node, and the separation section is tangent to the circle where the pre-gathering section is located. The negative Poisson's ratio ligament chiral structure dot matrix material is laid on the reflecting surface of an antenna reflecting surface made of a dot matrix structure, and the boundary of the laid pre-folded six-ligament chiral structure dot matrix material is flat.

Description

Technical Field

[0001] The present invention relates to a negative Poisson's ratio ligament chiral structure lattice structure and an antenna reflector made thereof, belonging to the technical field of satellite antenna reflectors. Background Art

[0002] Mesh deployable antennas have been fully developed and widely used due to their advantages in terms of deployed aperture, stowage ratio, areal density, surface accuracy, and operating frequency. However, for their reflector material - traditional metal mesh, due to the lack of bending stiffness, under the action of pre-tension, the intercostal mesh surface is not a paraboloid of revolution with the same curvature direction as the curved surface, but a special curved surface that bulges radially outward and concaves inward circumferentially with a reverse curvature property, which reduces the surface accuracy of the antenna and affects the electrical performance of the antenna.

[0003] The most direct method to solve the anti-pillow effect in current engineering is to increase the number of radial ribs, but this method will bring problems such as increased mechanism complexity, reduced antenna reliability, and increased antenna weight.

[0004] Some other methods are based on the theory of shell without moments, such as applying out-of-plane loads. Inflatable antennas, electrostatic thin film antennas, and tension rod antennas are all based on this method. However, the reliability of inflatable antennas and electrostatic thin film antennas is uncertain and there are still technical problems at present; in order to improve the surface accuracy, tension rod antennas will also face problems of increased mechanism complexity and antenna weight. Summary of the Invention

[0005] The technical problem solved by the present invention is: to overcome the deficiencies of the prior art and provide a negative Poisson's ratio ligament chiral structure lattice structure and an antenna reflector made thereof, which are used to weaken the effect of the anti-pillow effect.

[0006] The technical solution of the present invention is: a negative Poisson's ratio ligament chiral structure lattice structure, which structure includes a plurality of pre-folded six-ligament chiral cells arranged regularly in repetition. Each six-ligament chiral cell includes six ligaments and a circular node; the ligaments are divided into three parts: a transition section, a pre-folded section, and a separation section. One end of the transition section is the starting end of the ligament, which is used to connect the circular node, and the other end is connected to one end of the pre-folded section. The other end of the pre-folded section is connected to the separation section, and the other end of the separation section is the end of the ligament, which is used to connect to the end of the ligament of another pre-folded six-ligament chiral cell;

[0007] The pre-folded section is an arc in a concentric circle of the circular node, and there is a processing gap between it and the circular node. The separation section is tangent to the circle where the pre-folded section is located.

[0008] Preferably, the range of the central angle corresponding to the pre-folded section is 0 to 60°.

[0009] Preferably, the ratio L / R of twice the ligament length L to the center distance R of adjacent circular nodes ranges from 0.4 to 1.0.

[0010] Preferably, the width of the transition section is the sum of the width of the pre-converging section, the width of the circular node, and the width of the processing gap.

[0011] Preferably, the widths of the pre-converging section, the separating section, and the circular node are equal.

[0012] Preferably, the six ligaments are of equal length.

[0013] Preferably, it is made of a metal or non-metal material with a thickness not greater than 0.6 mm by laser cutting or wire cutting.

[0014] Preferably, the metal is beryllium bronze, aluminum alloy, or titanium alloy.

[0015] Preferably, the non-metal is polyimide or polytetrafluoroethylene.

[0016] Another technical solution of the present invention is: an antenna reflector made of a negative Poisson's ratio ligament chiral structure lattice structure, on which the negative Poisson's ratio ligament chiral structure lattice material described in claim 1 is laid, and the boundary of the laid pre-converging six-ligament chiral structure lattice material is flat.

[0017] The advantages of the present invention compared with the prior art are as follows:

[0018] (1), By designing the antenna reflector with a negative Poisson's ratio, the obtained antenna reflector has a certain bending stiffness, so that the phenomenon of radial outward convexity and circumferential inward concavity under the action of pre-tension is alleviated, thereby weakening the effect of the anti-pillow effect.

[0019] (2), The negative Poisson's ratio ligament chiral structure lattice structure proposed by the present invention breaks out of the constraint of the membrane theory, realizes a negative Poisson's ratio, and the Gaussian curvature of each point on the deformed surface obtained after bending is positive.

[0020] (3), When processing the material of the present invention, it is directly processed and formed by laser cutting or wire cutting. The obtained lattice material has a stable and obvious negative Poisson's ratio effect when subjected to a tensile load, and the processing method is simpler and more reliable.

[0021] (4), The negative Poisson's ratio ligament chiral structure lattice structure is laid on the antenna reflector of the present invention. When adjusting the surface accuracy of the reflector, the number of adjustment points required is less, which can reduce the complexity of the mechanism and improve the reliability. Description of the Drawings

[0022] Figure 1This is the pre - folded six - ligament chiral unit cell of the embodiment of the present invention, showing each component part.

[0023] Figure 2 This is the cell parameters of the pre - folded six - ligament chiral unit cell of the embodiment of the present invention.

[0024] Figure 3 This is a schematic diagram of a pre - folded six - ligament chiral structure lattice material sample composed of multiple repetitively and regularly arranged pre - folded six - ligament chiral unit cells in the embodiment of the present invention.

[0025] In the figure, 1 is the ligament, 2 is the circular node, 3 is the transition section, 4 is the pre - folded section, 5 is the separation section, 6 is the processing gap, R is the center - to - center distance of the circular nodes of two adjacent unit cells, and L is the total length of the ligaments in the separation section of two adjacent unit cells. Detailed implementation mode

[0026] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0027] As Figure 1 shown, based on the classic six - ligament chiral unit cell, the present invention conducts a pre - folding design on the classic six - ligament chiral unit cell to obtain a pre - folded six - ligament chiral unit cell. The pre - folded six - ligament chiral unit cell includes six ligaments 1 and a circular node 2; the ligament 1 is divided into three parts: a transition section 3, a pre - folded section 4, and a separation section 5. One end of the transition section 3 is the starting end of the ligament 1, which is used to connect the circular node 2, and the other end is connected to one end of the pre - folded section 4. The other end of the pre - folded section 4 is connected to the separation section 5, and the other end of the separation section 5 is the end of the ligament 1, which is used to connect with the end of the ligament 1 of another pre - folded six - ligament chiral unit cell; the lengths of the six ligaments 1 of each six - ligament chiral unit cell are equal, and the included angle between two adjacent ligaments is 60°.

[0028] The pre - folding property of the pre - folded six - ligament chiral unit cell is reflected by the pre - folded section 4. The pre - folded section 4 is an arc in a concentric circle of the circular node 2, and there is a processing gap 6 between it and the circular node 2. The separation section 5 is tangent to the circle where the pre - folded section 4 is located.

[0029] The range of the central angle corresponding to the pre - folded section 4 is 0 - 60°.

[0030] The transition section 3 plays a role in connecting the ligament 1 and the circular node 2. The width of the transition section 3 is the sum of the width of the pre - folded section 4, the width of the circular node 2, and the width of the processing gap 6.

[0031] The widths of the pre - folded section 4, the separation section 5, and the circular node 2 can be equal or not equal. Preferably, the widths of the pre - folded section 4, the separation section 5, and the circular node 2 are equal.

[0032] The pre - folding structure is realized by machining, and thin materials are directly processed into shape by machining. When machining the pre - folding six - ligament chiral structure lattice structure, it is made of metal or non - metal materials with a thickness not greater than 0.6 mm by laser cutting or wire cutting.

[0033] The metal can be beryllium bronze, aluminum alloy, titanium alloy, etc.

[0034] The non - metal can be polyimide or polytetrafluoroethylene.

[0035] As Figure 3 shown, the lattice material with the pre - folding six - ligament chiral structure has the property of negative Poisson's ratio. When the lattice material with the pre - folding six - ligament chiral structure is stretched transversely, its longitudinal direction will expand. Define the center - to - center distance of the circular nodes 2 of two adjacent pre - folding six - ligament chiral cells as R, and the length of the ligament 1 of the separated section 6 of two adjacent pre - folding six - ligament chiral cells as L (so the length of the ligament 1 of the separated section 6 in a single cell is L / 2). The value of the negative Poisson's ratio is related to the ratio L / R of the length L of the ligament 1 of two adjacent cells and the center - to - center distance R of the circular nodes 2 of two adjacent cells. In order to obtain an antenna reflector with better surface accuracy, the closer the negative Poisson's ratio is to - 1, the better. Therefore, as Figure 2 shown, to ensure the harmony of the cell shape and maintain the corresponding properties, the value range of the ratio L / R of 2 times the ligament length L to the center - to - center distance R of adjacent circular nodes is preferably 0.4 - 1.0.

[0036] The present invention cuts a large - size sample into a suitable shape and lays it on one reflector surface of a 1 - m - diameter umbrella antenna prototype, and lays a traditional metal mesh on the adjacent reflector surface for comparison. When measuring the surface accuracy of the two reflector surfaces without adjustment, it is found that the surface accuracy of the material with the pre - folding six - ligament chiral structure is better than that of the traditional metal mesh. Comparing the part of the traditional metal mesh reflector and the reflector surface of the pre - folding six - ligament chiral structure lattice material at the tip of the umbrella antenna, it can be observed that the boundary of the traditional metal mesh presents a catenary after tensioning, but the boundary of the pre - folding six - ligament chiral structure lattice material is flat, avoiding the appearance of the catenary, which shows that the pre - folding six - ligament chiral structure lattice material can weaken the back - pillow effect to a certain extent. Adjust the surface accuracy of the two reflector surfaces. When reaching the same design accuracy, the traditional metal mesh requires 25 adjustment points, while the pre - folding six - ligament chiral structure lattice material only requires 5 adjustment points, which simplifies the antenna structure.

[0037] Based on the above theory, the present invention also provides an antenna reflector made of a negative Poisson's ratio ligament chiral structure lattice structure. The above - mentioned negative Poisson's ratio ligament chiral structure lattice material is laid on the reflector surface of the antenna reflector, and the boundary of the laid pre - folding six - ligament chiral structure lattice material is flat.

[0038] Embodiment 1:

[0039] In this embodiment, a polyimide sample with an L / R of 0.83 is processed by laser cutting.

[0040] In this embodiment, the ligament length of the pre-collapsed six-ligament chiral structure cell is 7.15 mm, the circular node radius is 3.50 mm, the ratio L / R of twice the ligament length L to the center distance R of adjacent circular nodes is 0.83, the circular node width and the ligament width are both 0.4 mm, the pre-collapsed section angle is 30°, and a polyimide film with a thickness of 0.6 mm is selected. 180mmx180mmx0.6mm and 600mmx600mmx0.6mm material samples are processed by laser cutting. The small-size samples are subjected to stretching and bending tests, and the Poisson's ratio of the sample is measured to be -0.754. The Gaussian curvature of each point on the deformed surface obtained after bending is positive.

[0041] Embodiment 2:

[0042] In this embodiment, a beryllium bronze sample with an L / R of 0.76 is processed by laser cutting.

[0043] In this embodiment, the ligament length of the pre-collapsed six-ligament chiral structure cell is 4.59 mm, the circular node radius is 3.35 mm, the ratio L / R of twice the ligament length L to the center distance R of adjacent circular nodes is 0.76, the circular node width and the ligament width are both 0.4 mm, the angle of the pre-collapsed section is 25°, beryllium bronze with a thickness of 0.6 mm is selected, and the material sample is processed by laser. The sample is subjected to tensile and bending tests, and the Poisson's ratio of the sample is measured to be -0.662, and the Gaussian curvature of each point on the deformed surface obtained after bending is positive.

[0044] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A negative Poisson's ratio ligament chiral structure lattice structure, characterized in that It comprises a plurality of pre-folded six-ligament chiral cells which are arranged in a repetitive and regular manner, each of which comprises six ligaments (1) and a circular node (2); the ligament (1) is divided into three parts, namely a transition section (3), a pre-folded section (4) and a separation section (5); one end of the transition section (3) is the starting end of the ligament (1) and is used to connect to the circular node (2); the other end is connected to one end of the pre-folded section (4); the other end of the pre-folded section (4) is connected to the separation section (5); the other end of the separation section (5) serves as the end of the ligament (1) and is used to connect to the end of the ligament (1) of another pre-folded six-ligament chiral cell; The pre-collapsed section (4) is an arc in the concentric circle of the circular node (2), and there is a processing gap (6) between the pre-collapsed section (4) and the circular node (2). The separation section (5) is tangent to the circle where the pre-collapsed section (4) is located.

2. The chiral structure lattice structure of a negative Poisson's ratio ligament according to claim 1, characterized in that, The central angle corresponding to the pre-collapsed section (4) has a value range of 0 to 60°.

3. The chiral structure lattice structure of a negative Poisson's ratio ligament according to claim 1, wherein The ratio of twice the ligament length L to the distance between the centers of adjacent circular nodes R ranges from 0.4 to 1.

0.

4. The chiral structure lattice structure of a negative Poisson's ratio ligament according to claim 1, characterized in that The width of the transition section (3) is the sum of the width of the pre-collapsed section (4), the width of the circular node (2), and the width of the processed gap (6).

5. A negative Poisson's ratio ligament chiral structure lattice structure according to claim 1, characterized in that, The width of the pre-collapsed section (4), the width of the separated section (5), and the width of the circular node (2) are equal.

6. The chiral structure lattice structure of a negative Poisson's ratio ligament according to claim 1, characterized in that, The six ligaments (1) are of equal length.

7. A negative Poisson's ratio ligament chiral structure lattice structure according to claim 1, characterized in that, It is made of metal or non-metal materials with a thickness not exceeding 0.6mm by laser cutting or wire cutting.

8. A negative Poisson's ratio ligament chiral structure lattice structure according to claim 7, characterized in that, The metal is beryllium bronze, aluminum alloy or titanium alloy.

9. The chiral structure lattice structure of a negative Poisson's ratio ligament according to claim 7, characterized in that The non-metal is polyimide or polytetrafluoroethylene.

10. An antenna reflector made of a negative Poisson's ratio ligament chiral structure lattice structure, characterized in that, The negative Poisson's ratio ligament chiral structure lattice material according to claim 1 is laid on the reflecting surface of the antenna reflecting surface, and the boundary of the pre-collapsed six-ligament chiral structure lattice material is smooth after laying.

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