Truss structure for aerospace

Abstract

The present invention belongs to the technical field of spacecraft structures, and particularly relates to a truss structure for aerospace applications. The truss structure for aerospace applications in the present invention is assembled from multiple double-arrow zero-expansion cells. Each double-arrow zero-expansion cell is composed of three planar double-arrow elements. The included angle between two adjacent planar double-arrow elements is 60°. The planar double-arrow element includes an upper-arrow part and a lower-arrow part. The material thermal expansion coefficients of the upper-arrow part and the lower-arrow part of the same planar double-arrow element are different, and the thermal expansion deformations of the upper-arrow part material and the lower-arrow part material of the same planar double-arrow element are complementary under the action of temperature load, so that the double-arrow zero-expansion cell can maintain a constant height in the presence of temperature load, and further enables the truss structure for aerospace applications assembled from multiple double-arrow zero-expansion cells to effectively eliminate structural thermal deformation, thereby having excellent zero-expansion characteristics.

Description

Technical Field

[0001] The present invention belongs to the technical field of spacecraft structures, and particularly relates to a truss structure for aerospace applications. Background Art

[0002] In space, the temperature difference between the sun-facing side and the shaded side of a spacecraft exceeds 300 °C, and the heat absorption of the spacecraft changes significantly with time as it orbits. In such an environment, the thermal expansion and contraction effects of conventional materials can cause deviations in the positioning or focusing of load devices on the spacecraft, such as optical remote sensing systems, space cameras, antennas, etc., affecting their accuracy.

[0003] Therefore, in order to ensure the reliable operation of the spacecraft, there is an urgent need for a truss structure that does not undergo thermal deformation as a support for the devices. However, the degree of thermal deformation of traditional truss structures is still relatively high. Therefore, there is an urgent need for a truss structure for aerospace applications to solve this problem. Summary of the Invention

[0004] The purpose of the present invention is to provide a truss structure for aerospace applications to solve the problem that the degree of thermal deformation of the above-mentioned traditional truss structure is still relatively high.

[0005] To achieve the above purpose, the present invention provides the following solution:

[0006] A truss structure for aerospace applications, comprising: a plurality of double-arrow zero-expansion cell groups, the plurality of double-arrow zero-expansion cell groups are fixedly connected in sequence from bottom to top, the double-arrow zero-expansion cell group includes a plurality of double-arrow zero-expansion cells, the plurality of double-arrow zero-expansion cells are located on the same plane, a plurality of connection points are circumferentially and equally spaced on the double-arrow zero-expansion cell, and the connection point is fixedly connected to the connection point on another double-arrow zero-expansion cell;

[0007] The double-arrow zero-expansion cell includes three planar double-arrow elements, the included angle between two adjacent planar double-arrow elements is 60°, the planar double-arrow element includes an upper-arrow part and a lower-arrow part, and the thermal expansion coefficients of the upper-arrow part and the lower-arrow part are different.

[0008] Preferably, the upper-arrow part includes two symmetrically arranged upper hypotenuses, one end of the two upper hypotenuses is fixedly connected to form an upper vertex, the lower-arrow part includes two symmetrically arranged lower hypotenuses, one end of the two lower hypotenuses is fixedly connected to form a lower vertex, one end of the upper hypotenuse away from the other upper hypotenuse is fixedly connected to one end of the lower hypotenuse away from the other lower hypotenuse to form the connection point, the upper vertices of the three planar double-arrow elements in the same double-arrow zero-expansion cell are fixedly connected, the lower vertices of the three planar double-arrow elements in the same double-arrow zero-expansion cell are fixedly connected, and the thermal expansion coefficients of the upper hypotenuse and the lower hypotenuse are different.

[0009] Preferably, the relationship between the length of the upper hypotenuse and the length of the lower hypotenuse satisfies the formula:

[0010]

[0011] wherein, L1 is the side length of the upper hypotenuse, L2 is the side length of the lower hypotenuse, θ is the angle between the upper hypotenuse and the axis of symmetry, and β is the angle between the lower hypotenuse and the axis of symmetry.

[0012] Preferably, the relationship between the coefficient of thermal expansion of the upper hypotenuse and the coefficient of thermal expansion of the lower hypotenuse satisfies the formula:

[0013]

[0014] wherein, α1 is the coefficient of thermal expansion of the material of the upper hypotenuse, and α2 is the coefficient of thermal expansion of the material of the lower hypotenuse.

[0015] Compared with the prior art, the present invention has the following advantages and technical effects:

[0016] The truss structure for aerospace in the present invention is assembled by a plurality of double-arrow zero-expansion cells. Each double-arrow zero-expansion cell is composed of three planar double-arrow elements. The angle between two adjacent planar double-arrow elements is 60°. The planar double-arrow element includes an upper arrow part and a lower arrow part. The vertex of the upper arrow part of the planar double-arrow element located below is fixedly connected to the vertex of the lower arrow part of the planar double-arrow element located above. The coefficients of thermal expansion of the materials of the upper arrow part and the lower arrow part of the same planar double-arrow element are different, and the thermal expansion deformations of the materials of the upper arrow part and the lower arrow part of the same planar double-arrow element are complementary under the action of temperature load, so that the double-arrow zero-expansion cell can maintain a constant height under the condition of having a temperature load, and further enable the truss structure for aerospace assembled by a plurality of double-arrow zero-expansion cells to effectively eliminate structural thermal deformation, thereby having excellent zero-expansion characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts:

[0018] Figure 1 is a schematic diagram of the overall structure of the present invention;

[0019] Figure 2 is the front view of the present invention;

[0020] Figure 3The left view of the present invention;

[0021] Figure 4 The top view of the present invention;

[0022] Figure 5 The structural schematic diagram of the double-arrow zero-expansion cell in the present invention;

[0023] Figure 6 The structural schematic diagram of the planar double-arrow element in the present invention;

[0024] Figure 7 The schematic diagram of the height change of the truss structure for aerospace applications of the present invention at different temperatures;

[0025] Wherein, 111, the upper hypotenuse; 112, the lower hypotenuse. Specific embodiments

[0026] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0027] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0028] Refer to Figures 1 to 6 , the present invention discloses a truss structure for aerospace applications, including: a plurality of double-arrow zero-expansion cell groups, the plurality of double-arrow zero-expansion cell groups are fixedly connected in sequence from bottom to top, the double-arrow zero-expansion cell group includes a plurality of double-arrow zero-expansion cells, the plurality of double-arrow zero-expansion cells are located on the same plane, a plurality of connection points are circumferentially and equally spaced on the double-arrow zero-expansion cell, and the connection point is fixedly connected to the connection point on another double-arrow zero-expansion cell;

[0029] The double-arrow zero-expansion cell includes three planar double-arrow elements, the included angle between two adjacent planar double-arrow elements is 60°, the planar double-arrow element includes an upper arrow part and a lower arrow part, and the thermal expansion coefficients of the upper arrow part and the lower arrow part are different.

[0030] The space truss structure in this device is assembled from multiple double-arrow zero-expansion cells. Each double-arrow zero-expansion cell consists of three planar double-arrow elements. The included angle between two adjacent planar double-arrow elements is 60°. The planar double-arrow element includes an upper arrow part and a lower arrow part. The vertex of the upper arrow part of the planar double-arrow element located below is fixedly connected to the vertex of the lower arrow part of the planar double-arrow element located above. The material thermal expansion coefficients of the upper arrow part and the lower arrow part of the same planar double-arrow element are different, and the thermal expansion deformations of the upper arrow part material and the lower arrow part material of the same planar double-arrow element are complementary under the action of temperature load, so that the double-arrow zero-expansion cell can maintain a constant height under the condition of having a temperature load, and further enable the space truss structure assembled from multiple double-arrow zero-expansion cells to effectively eliminate structural thermal deformation, thus having excellent zero-expansion characteristics.

[0031] In a further optimized solution, the upper arrow part includes two symmetrically arranged upper hypotenuses 111. One ends of the two upper hypotenuses 111 are fixedly connected to form an upper vertex. The lower arrow part includes two symmetrically arranged lower hypotenuses 112. One ends of the two lower hypotenuses 112 are fixedly connected to form a lower vertex. The end of the upper hypotenuse 111 far from the other upper hypotenuse 111 is fixedly connected to the end of the lower hypotenuse 112 far from the other lower hypotenuse 112 to form a connection point. The upper vertices of the three planar double-arrow elements within the same double-arrow zero-expansion cell are fixedly connected, and the lower vertices of the three planar double-arrow elements within the same double-arrow zero-expansion cell are fixedly connected. The thermal expansion coefficients of the upper hypotenuse 111 and the lower hypotenuse 112 are different.

[0032] Among them, the cross-sectional shapes of the upper hypotenuse 111 and the lower hypotenuse 112 are circular or rectangular.

[0033] The materials of the upper hypotenuse 111 and the lower hypotenuse 112 can be selected from one of austenitic stainless steel, nickel alloy, carbon steel, martensitic stainless steel, Hastelloy, molybdenum alloy, and chromium steel.

[0034] In a further optimized solution, the relationship between the length of the upper hypotenuse 111 and the length of the lower hypotenuse 112 satisfies the formula:

[0035]

[0036] Among them, L1 is the side length of the upper hypotenuse 111, L2 is the side length of the lower hypotenuse 112, θ is the included angle between the upper hypotenuse 111 and the axis of symmetry, and β is the included angle between the lower hypotenuse 112 and the axis of symmetry.

[0037] In a further optimized solution, the relationship between the thermal expansion coefficient of the upper hypotenuse 111 and the thermal expansion coefficient of the lower hypotenuse 112 satisfies the formula:

[0038]

[0039] Among them, α1 is the thermal expansion coefficient of the material of the upper hypotenuse 111, and α2 is the thermal expansion coefficient of the material of the lower hypotenuse 112.

[0040] One specific example:

[0041] The material of the upper hypotenuse 111 is selected as molybdenum alloy, preferably tungsten molybdenum alloy, and the material of the lower hypotenuse 112 is selected as carbon steel, preferably low carbon steel; the elastic modulus E1 of the molybdenum alloy is 230 GPa, the Poisson's ratio μ1 is 0.30, and the thermal expansion coefficient α1 is 6.0×10 -6 / °C; the elastic modulus E2 of the carbon steel is 200 GPa, the Poisson's ratio μ2 is 0.30, and the thermal expansion coefficient α2 is 12×10 -6 / °C.

[0042] A model is established in the finite element software ANSYS. The material of the upper hypotenuse 111 is molybdenum alloy, the length is L1 = 10 mm, and the diameter is The material of the lower hypotenuse 112 is carbon steel, the length is L2 = 7.07 mm, and the diameter is The thermal expansion coefficient between the vertex of the upper arrow part and the vertex of the lower arrow part can be adjusted by θ. Therefore, θ = 45°, 40°, 35° and 30° are taken respectively, and β can be calculated according to the formula.

[0043] Construct a double-arrow zero-expansion unit cell: Rotate the planar double-arrow element by 60° and 120° around the connecting line between the vertex of the upper arrow part and the vertex of the lower arrow part to form a double-arrow zero-expansion unit cell;

[0044] Construct a truss structure for aerospace: Take the intersection point of the upper arrow part and the lower arrow part of the planar double-arrow element as the connection point, and each connection point is connected to the connection point on another double-arrow zero-expansion unit cell to form a group of double-arrow zero-expansion unit cells. A number of groups of double-arrow zero-expansion unit cells are arranged in sequence from bottom to top. The vertex of the lower arrow part in the upper planar double-arrow element is fixedly connected to the vertex of the upper arrow part of the lower planar double-arrow element to form a truss structure for aerospace.

[0045] The double-arrow zero-expansion unit cell in the truss structure for aerospace is prepared by 3D printing.

[0046] Refer to Figure 7 , which is a schematic diagram of the height change of the truss structure for aerospace in the present invention at different temperatures.

[0047] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the present invention.

[0048] The embodiments described above are only for describing the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the spirit of the design of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. Truss structure for aerospace, characterized in that, Including: A plurality of double-arrow zero-expansion cell groups, and the plurality of double-arrow zero-expansion cell groups are fixedly connected in sequence from bottom to top. The double-arrow zero-expansion cell group includes a plurality of double-arrow zero-expansion cells, and the plurality of double-arrow zero-expansion cells are located on the same plane. A plurality of connection points are circumferentially and equally spaced on the double-arrow zero-expansion cell, and the connection point is fixedly connected to the connection point on another double-arrow zero-expansion cell; The double-arrow zero-expansion cell includes three planar double-arrow elements, and the included angle between two adjacent planar double-arrow elements is 60°. The planar double-arrow element includes an upper arrow part and a lower arrow part, and the thermal expansion coefficients of the upper arrow part and the lower arrow part are different; The upper arrow part includes two symmetrically arranged upper hypotenuses (111), and one ends of the two upper hypotenuses (111) are fixedly connected to form an upper vertex. The lower arrow part includes two symmetrically arranged lower hypotenuses (112), and one ends of the two lower hypotenuses (112) are fixedly connected to form a lower vertex. One end of the upper hypotenuse (111) far from the other upper hypotenuse (111) is fixedly connected to one end of the lower hypotenuse (112) far from the other lower hypotenuse (112) to form the connection point. The upper vertices of the three planar double-arrow elements in the same double-arrow zero-expansion cell are fixedly connected, and the lower vertices of the three planar double-arrow elements in the same double-arrow zero-expansion cell are fixedly connected. The thermal expansion coefficients of the upper hypotenuse (111) and the lower hypotenuse (112) are different.

2. The truss structure for aerospace according to claim 1, characterized in that: The relationship between the length of the upper hypotenuse (111) and the length of the lower hypotenuse (112) satisfies the formula: ， Wherein, L1 is the side length of the upper hypotenuse (111), L2 is the side length of the lower hypotenuse (112), θ is the included angle between the upper hypotenuse (111) and the symmetry axis, and β is the included angle between the lower hypotenuse (112) and the symmetry axis.

3. The truss structure for aerospace use according to claim 2, wherein: The relationship between the thermal expansion coefficient of the upper hypotenuse (111) and the thermal expansion coefficient of the lower hypotenuse (112) satisfies the formula: ， Wherein, α1 is the thermal expansion coefficient of the material of the upper hypotenuse (111), and α2 is the thermal expansion coefficient of the material of the lower hypotenuse (112).

Images