A kind of positive quadrilateral origami-based thermal expansion coefficient controllable three-dimensional metamaterial structure

Abstract

The application relates to the technical field of metamaterials, and aims to provide a three-dimensional metamaterial structure with adjustable thermal expansion coefficient based on a regular quadrilateral paper folding structure, which has the characteristics of adjustable thermal expansion coefficient, simple structure and wide application range. The technical scheme is a three-dimensional metamaterial structure with adjustable thermal expansion coefficient based on a regular quadrilateral paper folding structure, which is characterized in that the structure comprises a body structure and two driving rods symmetrically arranged in the body structure; the body structure comprises four two-dimensional units connected in sequence; each two-dimensional unit is composed of a horizontal rod, an inclined rod and a horizontal rod connected in sequence, two horizontal rods in the two-dimensional unit are arranged in parallel, and the axes of the two horizontal rods and the axis of the inclined rod are located in the same plane; the two ends of the driving rod are fixed to the connecting ends of two two-dimensional units in pairs, and the axes of the two horizontal rods connected at the connecting end and the axis of the driving rod are located in the same plane.

Description

Technical Field

[0001] The present invention relates to the field of metamaterial technology, and in particular to a three-dimensional metamaterial structure with controllable thermal expansion coefficient based on regular tetragonal origami. Background Art

[0002] Metamaterials are artificially designed structures that exhibit unusual physical properties, such as a negative Poisson's ratio, negative thermal expansion coefficient, and negative refractive index. The properties of metamaterials are influenced by both the material properties and the design, with the design being a key factor. Due to their unique physical properties, metamaterials are widely used in aerospace, fiber optic communications, optical devices, and other fields.

[0003] As a type of metamaterial, metamaterials with tunable thermal expansion coefficients can achieve controllable thermal expansion coefficients from positive to negative, provided their geometric parameters are properly designed. Currently, some three-dimensional metamaterial structures with tunable thermal expansion coefficients exist, but these structures are complex. Therefore, it is necessary to design a class of three-dimensional metastructures that possess simple structures, tunable thermal expansion coefficients, and a wide range of applications. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies in the above-mentioned background technology and provide a three-dimensional metamaterial structure with controllable thermal expansion coefficient based on regular tetragonal origami, which has the characteristics of controllable thermal expansion coefficient, simple structure and wide range of applications.

[0005] The technical solution of the present invention is:

[0006] A three-dimensional metamaterial structure with controllable thermal expansion coefficient based on regular tetragonal origami, characterized in that: the structure includes a main body structure and two driving rods symmetrically arranged in the main body structure; the main body structure includes four two-dimensional units connected in sequence; each two-dimensional unit is composed of a cross bar, an oblique bar, and a cross bar connected in series in sequence, wherein two cross bars are arranged parallel to each other and the axes of the two cross bars are located in the same plane as the axes of the oblique bars; the two ends of the driving rod are respectively fixed to the connecting ends of two adjacent two-dimensional units, and the axes of the two cross bars connected at the connecting ends are located in the same plane as the axis of the driving rod.

[0007] The main body structure is a regular quadrilateral single closed loop structure composed of four two-dimensional units connected in sequence, the planes where adjacent two-dimensional units are located are perpendicular to each other, and the single closed loop structure is symmetrical about the vertical plane where the diagonal vertices are located.

[0008] The two ends of the driving rod are respectively located at diagonal vertices of the main body structure.

[0009] The cross bars, the oblique bars and the driving bars are all connected in a fixed manner, and the cross sections of the bars are all rectangular and of the same size.

[0010] The driving rod is made of a material with a high thermal expansion coefficient, and aluminum alloy can be selected; the cross bar and the oblique bar are made of a material with a low thermal expansion coefficient, and low carbon steel can be selected.

[0011] When heated, the drive rods extend, pushing the metamaterial structure toward flattening, thereby achieving the change in height.

[0012] The beneficial effects of the present invention are as follows: the metamaterial structure proposed in the present invention has the advantages of adjustable thermal expansion coefficient, simple structure, wide application range, etc., and can be used in aerospace, precision instruments and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a structural schematic diagram of the present invention.

[0014] Figure 2 This is a graph showing how the equivalent thermal expansion coefficient of the present invention changes with θ when L=50 mm and B=30 mm.

[0015] Figure 3 This is a curve diagram showing how the equivalent thermal expansion coefficient of the present invention changes with L when B=30 mm and θ=60°.

[0016] Figure 4 This is a curve diagram showing how the equivalent thermal expansion coefficient of the present invention changes with L when B=30 mm and θ=90°.

[0017] Figure 5 This is a curve diagram showing how the equivalent thermal expansion coefficient of the present invention changes with L when B=30 mm and θ=120°.

[0018] Figure 6 This is a curve diagram showing how the equivalent thermal expansion coefficient of the present invention changes with B when L=50 mm and θ=60°.

[0019] Figure 7 This is a curve diagram showing how the equivalent thermal expansion coefficient of the present invention changes with B when L=50 mm and θ=90°.

[0020] Figure 8 This is a curve diagram showing how the equivalent thermal expansion coefficient of the present invention changes with B when L=50 mm and θ=120°.

[0021] Numbers in the figure: cross bar 1, diagonal bar 2, driving rod 3. DETAILED DESCRIPTION

[0022] The present invention will be further described below with reference to the accompanying drawings, but the present invention is not limited to the following embodiments.

[0023] like Figure 1 The thermal expansion coefficient-controllable three-dimensional metamaterial structure based on regular tetragonal origami is characterized by: a main structure and two drive rods 3; the main structure comprises four two-dimensional units consisting of two crossbars 1 and one diagonal rod 2; the two-dimensional units are composed of crossbar 1, diagonal rod 2, and crossbar 1 connected in series, with two crossbars parallel to each other and arranged horizontally, and the axes of the two crossbars and the axis of the diagonal rod lying in the same vertical plane. The main structure is a regular tetragonal single closed loop structure composed of four two-dimensional units connected in series, with the planes of two adjacent two-dimensional units perpendicular to each other, and the single closed loop structure is symmetrical about the vertical planes of the diagonal vertices (as can be seen from the figure: the single closed loop structure has four diagonal vertices).

[0024] The two ends of the driving rod 3 are respectively located at diagonal vertices of the main body structure.

[0025] The connection between the rods is fixed connection, and the cross-section of each rod is rectangular and of the same size; preferably, the size of the rectangle can be 2mm×2mm.

[0026] The driving rod 3 is made of a material with a high thermal expansion coefficient, such as aluminum alloy; the cross bar 1 and the oblique bar 2 are made of a material with a low thermal expansion coefficient, such as low carbon steel.

[0027] The length of the cross bar 1 is L, the length of the diagonal bar 2 is B, and the angle between the cross bar and the diagonal bar is θ; the value of L is 30mm to 70mm, the value of B is L / 2 to L, and the value of θ is 20° to 160°.

[0028] The equivalent thermal expansion coefficient of the three-dimensional metamaterial structure (ie Figures 2 to 8 The vertical coordinate in the unit is 10 -6 / °C (represented as 1e-6 / °C in the figure) is the coefficient of change of the vertical dimension of the 3D metamaterial structure under heating. This equivalent thermal expansion coefficient is related to L, B, and θ; the specific details are demonstrated in the following experiments.

[0029] Figure 2 This is a graph showing how the equivalent thermal expansion coefficient of the present invention changes with θ when L = 50 mm and B = 30 mm. Curve AM represents the analytical solution, and the hollow circle FEM represents the result of finite element simulation. It can be seen that the two are in good agreement, and the equivalent thermal expansion coefficient of the structure decreases with increasing θ.

[0030] Figure 3This is a graph showing how the equivalent thermal expansion coefficient of the present invention changes with L when B = 30 mm and θ = 60°. The curve represents the analytical solution and the hollow circle represents the result of the finite element simulation. It can be seen that the two are in good agreement, and the equivalent thermal expansion coefficient of the structure increases with the increase of L.

[0031] Figure 4 This is a graph showing how the equivalent thermal expansion coefficient of the present invention changes with L when B = 30 mm and θ = 90°. The curve represents the analytical solution and the hollow circle represents the result of the finite element simulation. It can be seen that the two are in good agreement and the equivalent thermal expansion coefficient of the structure does not change with L.

[0032] Figure 5 This is a graph showing how the equivalent thermal expansion coefficient of the present invention changes with L when B = 30 mm and θ = 120°. The curve represents the analytical solution and the hollow circle represents the result of the finite element simulation. It can be seen that the two are in good agreement, and the equivalent thermal expansion coefficient of the structure decreases with increasing L.

[0033] Figure 6 This is a graph showing how the equivalent thermal expansion coefficient of the present invention changes with B when L = 50 mm and θ = 60°. The curve represents the analytical solution and the hollow circle represents the result of the finite element simulation. It can be seen that the two are in good agreement, and the equivalent thermal expansion coefficient of the structure decreases with increasing B.

[0034] Figure 7 This is a graph showing how the equivalent thermal expansion coefficient of the present invention changes with B when L = 50 mm and θ = 90°. The curve represents the analytical solution and the hollow circle represents the result of the finite element simulation. It can be seen that the two are in good agreement and the equivalent thermal expansion coefficient of the structure does not change with changes in B.

[0035] Figure 8 This is a graph showing how the equivalent thermal expansion coefficient of the present invention changes with B when L = 50 mm and θ = 120°. The curve represents the analytical solution and the hollow circle represents the result of the finite element simulation. It can be seen that the two are in good agreement, and the equivalent thermal expansion coefficient of the structure increases with the increase of B.

[0036] In summary, when the length L of the horizontal rod 1, the length B of the diagonal rod, and the angle θ between the horizontal rod and the diagonal rod are different, the equivalent thermal expansion coefficient of the three-dimensional metamaterial structure changes accordingly; therefore, the three-dimensional metastructure can be applied to different technical fields as needed.

Claims

1. A three-dimensional metamaterial structure with controllable thermal expansion coefficient based on regular tetragonal origami, characterized by: The structure comprises a main body structure and two driving rods (3) symmetrically arranged in the main body structure; the main body structure comprises four two-dimensional units connected in sequence; each two-dimensional unit is composed of a cross bar (1)-an oblique bar (2)-a cross bar connected in series in sequence, wherein two cross bars are arranged in parallel with each other and the axes of the two cross bars are located in the same plane as the axes of the oblique bars; the two ends of the driving rod are respectively fixed to the connecting ends of two adjacent two-dimensional units, and the axes of the two cross bars connected at the connecting ends are located in the same plane as the axis of the driving rod.

2. The three-dimensional metamaterial structure with controllable thermal expansion coefficient based on regular tetragonal origami according to claim 1, characterized in that: The main body structure is a regular quadrilateral single closed loop structure composed of four two-dimensional units connected in sequence, the planes where adjacent two-dimensional units are located are perpendicular to each other, and the single closed loop structure is symmetrical about the vertical plane where the diagonal vertices are located.

3. The three-dimensional metamaterial structure with controllable thermal expansion coefficient based on regular tetragonal origami according to claim 2, characterized in that: The two ends of the driving rod are respectively located at diagonal vertices of the main body structure.

4. The three-dimensional metamaterial structure with controllable thermal expansion coefficient based on regular tetragonal origami according to claim 3, characterized in that: The cross bars, the oblique bars and the driving bars are all connected in a fixed manner, and the cross sections of the bars are all rectangular and of the same size.

5. The three-dimensional metamaterial structure with controllable thermal expansion coefficient based on regular tetragonal origami according to claim 4, characterized in that: The driving rod is made of a material with a high thermal expansion coefficient; the cross bar and the oblique bar are made of a material with a low thermal expansion coefficient.

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