Thermal expansion and Poisson's ratio integrated adjustable two-dimensional metamaterial cell element and combination thereof

Abstract

The invention relates to a metamaterial, in particular to a thermal expansion and Poisson's ratio integrated adjustable two-dimensional metamaterial cell element and a combination thereof. The invention aims to provide a thermal expansion and Poisson's ratio integrated and adjustable metamaterial cell element, which has the characteristics of adjustable thermal expansion coefficient and adjustable Poisson's ratio. The technical scheme is a thermal expansion and Poisson's ratio integrated adjustable two-dimensional metamaterial cell element. The two-dimensional metamaterial cell element is characterized by comprising a quadrilateral unit and two semi-arrow units, wherein the quadrilateral unit is formed by sequentially connecting two first connecting rods and two second connecting rods end to end; each semi-arrow unit is formed by connecting one end of a third connecting rod with one end of a fourth connecting rod; wherein the connecting point of the first connecting rod and the second connecting rod is further connected with the other end of the third connecting rod, the two fourth connecting rods are coaxially arranged and pass through the connecting point of the two second connecting rods, and the first connecting rod, the second connecting rods, the third connecting rod and the fourth connecting rods are coplanar.

Description

Technical Field

[0001] The present invention relates to a metamaterial, in particular to a two-dimensional metamaterial cell with integrated and controllable thermal expansion and Poisson's ratio and a combination thereof. Background Art

[0002] Negative thermal expansion metamaterials can be widely used in aerospace, such as controlling thermal deformation of satellite antennas and spacecraft; in addition, in engineering fields such as precision instruments and electronics, materials with negative expansion or even zero expansion coefficients have high application value because the structure is easily affected by temperature fluctuations and requires high precision. Negative Poisson's ratio metamaterials can be used as the floor of explosion-proof vehicles. When the explosives at the bottom of the explosion-proof vehicle explode, the huge shock wave will cause the negative Poisson's ratio material to quickly gather at the impact point, increase density, increase strength, resist deformation, and ensure the safety of the people in the car; in addition, negative Poisson's ratio materials can also be used as car tires, seat belts and safety helmets, all of which benefit from their excellent energy absorption and buffering properties. Therefore, designing and developing more new metamaterials that integrate multiple mechanical properties and functions so that the material itself can serve for a long time under multi-field integrated working conditions is a key way to further improve the performance limit of materials. Summary of the invention

[0003] The purpose of the present invention is to overcome the deficiencies in the above-mentioned background technology and provide a metamaterial cell with integrated adjustable thermal expansion and Poisson's ratio. The material should have the characteristics of adjustable thermal expansion coefficient and adjustable Poisson's ratio.

[0004] The technical solution provided by the present invention is:

[0005] A thermal expansion and Poisson's ratio integrated and controllable two-dimensional metamaterial cell, characterized in that: the two-dimensional metamaterial cell includes a quadrilateral unit formed by two first connecting rods and two second connecting rods connected end to end in sequence, and two half-arrow units formed by connecting one end of a third connecting rod and one end of a fourth connecting rod respectively; wherein: the connection point between the first connecting rod and the second connecting rod is also connected to the other end of the third connecting rod, the two fourth connecting rods are coaxially arranged and pass through the connection point of the two second connecting rods, and the first connecting rod, the second connecting rod, the third connecting rod and the fourth connecting rod are coplanar.

[0006] The quadrilateral unit is symmetrical about the diagonal line, and the two half-arrow units are symmetrical about the diagonal line; the diagonal line is a line connecting the connection point of the two first connecting rods to the connection point of the two second connecting rods.

[0007] The two fourth connecting rods are perpendicular to the diagonal line.

[0008] The angle θ1 between the first link and the fourth link is less than 90 degrees; the angle θ3 between the second link and the fourth link is less than 90 degrees; the angle θ2 between the third link and the fourth link is greater than the angle θ3 between the second link and the fourth link and less than the supplementary angle of the angle θ1 between the first link and the fourth link.

[0009] The first connecting rod, the third connecting rod and the fourth connecting rod are made of materials with low thermal expansion coefficient; the second connecting rod is made of materials with high thermal expansion coefficient.

[0010] The adjustable three-dimensional metamaterial cell formed by the thermal expansion and Poisson's ratio integrated adjustable two-dimensional metamaterial cell is characterized in that: the three-dimensional metamaterial cell structure is constructed by two two-dimensional metamaterial cell structures with common vertices and bottom points, and the planes formed by the quadrilateral units in the two two-dimensional metamaterial cell structures are perpendicular to each other; the vertex is the connection point of the two first connecting rods, and the bottom point is the connection point of the two second connecting rods.

[0011] The adjustable three-dimensional metamaterial cell formed by the thermal expansion and Poisson's ratio integrated adjustable two-dimensional metamaterial cell is characterized in that: the three-dimensional metamaterial cell structure is a regular tetrahedral pyramid structure constructed by the common vertices of four two-dimensional metamaterial cell structures, and the four pyramid faces are all two-dimensional metamaterial cell structures.

[0012] The pyramid surface is a plane formed by the quadrilateral units, and two adjacent quadrilateral units share a first connecting rod, thereby forming the pyramid edge of the regular quadrangular pyramid-like structure.

[0013] The beneficial effect of the present invention is that the provided thermal expansion and Poisson's ratio integrated adjustable metamaterial cell integrates adjustable thermal expansion coefficient and adjustable Poisson's ratio, so that the material itself can serve for a long time under the working condition of coupling of temperature field and mechanical field. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the main structure of Example 1 of the present invention.

[0015] Figure 2 It is a schematic diagram of the three-dimensional structure of Example 2 of the present invention.

[0016] Figure 3 It is a schematic diagram of the three-dimensional structure of Example 3 of the present invention.

[0017] Numbers in the figure: first connecting rod 1, second connecting rod 2, third connecting rod 3, fourth connecting rod 4. DETAILED DESCRIPTION

[0018] The present invention will be further described below in conjunction with the embodiments shown in the accompanying drawings, but the present invention is not limited to the following embodiments.

[0019] Example 1

[0020] Figure 1 The thermal expansion and Poisson's ratio integrated adjustable two-dimensional metamaterial cell shown in the figure comprises a quadrilateral unit formed by two first links 1 and two second links 2 connected end to end in sequence, and two half-arrow units formed by connecting one end of a third link 3 and one end of a fourth link 4; wherein: the connection point of the two first links 1 is used as the vertex, and the connection point of the two second links 2 is used as the base; the line from the vertex to the base is a diagonal in the quadrilateral unit, and a first link 1 and a second link are symmetrically arranged on the left and right sides of the diagonal respectively; the connection point between the first link and the second link is also connected to the other end of the third link 3; the two fourth links are coaxially arranged and pass through the base, and are perpendicular to the diagonal; the first link, the second link, the third link and the fourth link are coplanar.

[0021] Obviously, the quadrilateral unit is symmetrical about the diagonal line; the two half-arrow units are symmetrical about the diagonal line; Figure 1 In the figure, the center line of the two-dimensional metamaterial cell coincides with the diagonal line.

[0022] The angle θ1 between the first link 1 and the fourth link 4 is less than 90 degrees; the angle θ3 between the second link 2 and the fourth link 4 is less than 90 degrees; the angle θ2 between the third link 3 and the fourth link 4 is greater than the angle θ3 between the second link 2 and the fourth link 4 and less than the supplementary angle of the angle θ1 between the first link and the fourth link.

[0023] The first connecting rod 1, the third connecting rod 3, and the fourth connecting rod 4 are made of low thermal expansion coefficient materials. The recommended low thermal expansion coefficient material is PVA material, and its thermal expansion coefficient is about 21e-6 / ℃; the second connecting rod 2 is made of high thermal expansion coefficient material. The recommended high thermal expansion coefficient material is nylon material, and its thermal expansion coefficient is about 166e-6 / ℃.

[0024] Example 2

[0025] Figure 2 A three-dimensional metamaterial cell structure shown is formed by two two-dimensional metamaterial cell structures with common vertices and bottom points, wherein the fourth connecting rod is perpendicular to the diagonal of the quadrilateral unit as the bottom edge (referred to as the vertical type), and the planes formed by the quadrilateral units in the two two-dimensional metamaterial cell structures are perpendicular to each other.

[0026] Example 3

[0027] Figure 3Another three-dimensional metamaterial cell structure shown is a regular tetrahedron-like structure constructed by four two-dimensional metamaterial cell structures sharing the same vertex, and the four pyramidal faces are all two-dimensional metamaterial cell structures (referred to as tetrahedron-like). The figure shows that the pyramidal face is a plane formed by the quadrilateral units in each two-dimensional metamaterial cell structure, and two adjacent quadrilateral units share a first connecting rod, thereby forming the pyramidal edge of the regular tetrahedron-like structure.

Claims

1. A two-dimensional metamaterial cell with integrated controllable thermal expansion and Poisson's ratio, characterized in that: The two-dimensional metamaterial cell comprises a quadrilateral unit formed by two first connecting rods (1) and two second connecting rods (2) connected end to end in sequence, and two half-arrow units formed by connecting one end of a third connecting rod (3) and one end of a fourth connecting rod (4) respectively; wherein: the connection point between the first connecting rod and the second connecting rod is also connected to the other end of the third connecting rod, the two fourth connecting rods are coaxially arranged and pass through the connection point of the two second connecting rods, and the first connecting rod, the second connecting rod, the third connecting rod and the fourth connecting rod are coplanar.

2. The thermal expansion and Poisson's ratio integrated controllable two-dimensional metamaterial cell according to claim 1, characterized in that: The quadrilateral unit is symmetrical about the diagonal line, and the two half-arrow units are symmetrical about the diagonal line; the diagonal line is a line connecting the connection point of the two first connecting rods to the connection point of the two second connecting rods.

3. The thermal expansion and Poisson's ratio integrated controllable two-dimensional metamaterial cell according to claim 2, characterized in that: The two fourth connecting rods are perpendicular to the diagonal line.

4. The thermal expansion and Poisson's ratio integrated controllable two-dimensional metamaterial cell according to claim 3, characterized in that: The angle θ1 between the first link and the fourth link is less than 90 degrees; the angle θ3 between the second link and the fourth link is less than 90 degrees; the angle θ2 between the third link and the fourth link is greater than the angle θ3 between the second link and the fourth link and less than the supplementary angle of the angle θ1 between the first link and the fourth link.

5. The thermal expansion and Poisson's ratio integrated controllable two-dimensional metamaterial cell according to claim 4, characterized in that: The first connecting rod, the third connecting rod and the fourth connecting rod are made of materials with low thermal expansion coefficient; the second connecting rod is made of materials with high thermal expansion coefficient.

6. The controllable three-dimensional metamaterial cell formed by the thermal expansion and Poisson's ratio integrated controllable two-dimensional metamaterial cell according to claim 1 is characterized in that: The three-dimensional metamaterial cell structure is constructed by two two-dimensional metamaterial cell structures that share a common vertex and a common bottom point, and the planes formed by the quadrilateral units in the two two-dimensional metamaterial cell structures are perpendicular to each other; the vertex is the connection point of the two first connecting rods, and the bottom point is the connection point of the two second connecting rods.

7. The controllable three-dimensional metamaterial cell formed by the thermal expansion and Poisson's ratio integrated controllable two-dimensional metamaterial cell according to claim 1 is characterized in that: The three-dimensional metamaterial cell structure is a regular tetrahedral pyramid structure constructed by sharing the same vertices of four two-dimensional metamaterial cell structures, and the four pyramid surfaces are all two-dimensional metamaterial cell structures.

8. The controllable three-dimensional metamaterial cell formed by integrating thermal expansion and Poisson's ratio controllable two-dimensional metamaterial cell according to claim 7, characterized in that: The pyramid surface is a plane formed by the quadrilateral units, and two adjacent quadrilateral units share a first connecting rod, thereby forming the pyramid edge of the regular quadrangular pyramid-like structure.

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