Negative Poisson's ratio two-dimensional unit cell structure and negative Poisson's ratio material

Abstract

The invention relates to a negative Poisson's ratio two-dimensional unit cell structure and a negative Poisson's ratio material, and belongs to the technical field of mechanical metamaterials. A quadrangular star-shaped main body of each quadrangular star-shaped unit is formed by sequentially connecting and encircling four first V-shaped rod bodies through opening ends, a first concave part is formed at the joint, and a first connecting rod is connected to the outer side of the first concave part; a double-arrow main body of the double-arrow unit is formed by a second V-shaped rod body through primary mirroring by taking a connecting line of two end points of an opening end as a symmetry axis, one end of the double-arrow main body is an arrow tip, the other end of the double-arrow main body is a second inner concave part, and a second connecting rod is connected to the outer side of the second inner concave part; according to the set number of the double-arrow units, the negative Poisson's ratio two-dimensional unit cell structure comprises a single-side arrow configuration and a double-side arrow configuration. The negative Poisson's ratio two-dimensional unit cell structure obtains a negative Poisson's ratio material through periodic arrangement in a plane. The negative Poisson's ratio characteristic is achieved through a simple structure.

Description

Technical Field

[0001] The present invention belongs to the technical field of mechanical metamaterials, and in particular relates to a negative Poisson's ratio two-dimensional unit cell structure and a negative Poisson's ratio material. Background Art

[0002] Metamaterials refer to composite materials that are artificially designed without violating the basic laws of physics and have extraordinary physical properties that natural materials do not have. They have great advantages in energy absorption, acoustics, optics, mechanical properties, etc. The performance of metamaterials is not only determined by the performance of the basic materials they are composed of, but also related to the structure they are designed into. Mechanical metamaterials are a large category of metamaterials, which refer to artificial materials with counterintuitive mechanical properties, also known as mechanical metamaterials, such as negative Poisson's ratio materials, negative compressibility materials, negative thermal expansion materials, negative stiffness materials, etc.

[0003] Negative Poisson's ratio materials are also called tensile materials, and their Poisson's ratio is negative. In conventional materials, when stretched by external force, the material usually shrinks in the direction perpendicular to the stretching direction. This phenomenon is called the positive Poisson's ratio effect. However, negative Poisson's ratio materials show a completely different behavior. When they are stretched, they expand in the direction perpendicular to the stretching direction. This unique property makes negative Poisson's ratio materials have potential application value in many engineering fields.

[0004] Taking the aerospace field as an example, traditional positive Poisson's ratio materials tend to produce unnecessary stress concentration in certain directions when subjected to external forces, which may cause damage to the material or degradation of its performance. Negative Poisson's ratio materials can disperse these stresses more effectively, thereby improving the overall strength and durability of the material. In addition to traditional structural components, negative Poisson's ratio materials can also be used for other innovative applications such as vibration reduction and noise reduction, thermal protection, etc. in aircraft. In addition, negative Poisson's ratio materials also have excellent energy absorption capabilities, which can significantly improve the impact resistance and fatigue resistance of the structure, which makes them have broad application prospects in protective equipment, shock-absorbing materials, etc.

[0005] Although there are some natural materials with negative Poisson's ratio effect in nature, the performance of these materials is often difficult to meet the needs of engineering applications. Therefore, it is more important to prepare negative Poisson's ratio materials with excellent performance through artificial synthesis and the use of advanced materials science and engineering technology. Summary of the invention

[0006] The purpose of the present invention is to provide a negative Poisson's ratio two-dimensional unit cell structure and a negative Poisson's ratio material, which have a simple structure and are easy to adjust, help solve the problem of material damage or performance degradation caused by stress concentration in the engineering field, and expand the types of metamaterials.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is: a negative Poisson's ratio two-dimensional unit cell structure, including connected four-pointed star units and double-arrow units; The four-pointed star unit includes a four-pointed star body, which is formed by four identical first V-shaped rods connected and surrounded in sequence through open ends, and the connection between two adjacent first V-shaped rods forms a first inner concave portion pointing to the centroid of the four-pointed star body, and the outer side of each first inner concave portion is also connected to a first connecting rod, and the extension line of each first connecting rod passes through the centroid of the four-pointed star body; The double-arrow unit comprises a double-arrow body, which is formed by a second V-shaped rod body with the line connecting the two end points of the open end as the symmetry axis and a mirror image, the two rod bodies of the second V-shaped rod body are of different lengths, one end of the double-arrow body on the symmetry axis is a convex arrow tip, and the other end is a second concave part, the outer side of the second concave part is connected to a second connecting rod, and the extension line of the second connecting rod passes through the arrow tip; The negative Poisson's ratio two-dimensional unit cell structure includes a single-sided arrow configuration and a double-sided arrow configuration. In the single-sided arrow configuration, one double-arrow unit is arranged on one side of the four-pointed star-shaped unit, and the arrow tip of the double arrow body in the double-arrow unit is connected to the first connecting rod; in the double-sided arrow configuration, two double-arrow units are arranged on opposite sides of the four-pointed star-shaped unit, and the arrow tips in the two double-arrow units are connected to the corresponding first connecting rods.

[0008] Furthermore, a Cartesian rectangular coordinate system is established with the centroid of the four-pointed star-shaped body as the coordinate origin, with the horizontal axis being the X-axis and the vertical axis being the Y-axis; the arrow tip and the second inner recess of the double-arrow unit are both located on the Y-axis, and the vertices of the two second V-shaped rods constituting the double-arrow body respectively have the same horizontal coordinate as the end of the first connecting rod on the same side.

[0009] Furthermore, the top angle of the first V-shaped rod is θ, the included angle between the first V-shaped rod and the adjacent first connecting rod is γ, and θ+90°=2γ.

[0010] The present invention also proposes another embodiment: a negative Poisson's ratio material, comprising a plurality of the negative Poisson's ratio two-dimensional unit cell structures described above, wherein the negative Poisson's ratio two-dimensional unit cell structures are periodically arranged in a plane to obtain a two-dimensional polyhedral structure.

[0011] As a specific implementation, when the negative Poisson's ratio two-dimensional unit cell structure is a single-sided arrow configuration, multiple negative Poisson's ratio two-dimensional unit cell structures are periodically arranged along the Y-axis direction, and the first connecting rod and the second connecting rod ends located on the Y-axis in two adjacent negative Poisson's ratio two-dimensional unit cell structures are connected, and then repeatedly mirrored along the X-axis direction to obtain a two-dimensional polyhedral structure.

[0012] As a specific implementation, when the negative Poisson's ratio two-dimensional unit cell structure is a double-sided arrow configuration, multiple negative Poisson's ratio two-dimensional unit cell structures are periodically arranged along the X-axis direction to form a transverse unit, and the two first connecting rod ends located on the X-axis in two adjacent negative Poisson's ratio two-dimensional unit cell structures are connected, and the vertices of the second V-shaped rod bodies of the double-arrow unit are connected; then multiple rows of transverse units are arranged along the Y-axis, and adjacent rows of transverse units are staggered along the X-axis by a certain distance to obtain a two-dimensional multi-cell structure, and the staggered distance is the length from the centroid of the star-shaped main body to the end of the first connecting rod on the x-axis.

[0013] Furthermore, the transverse units in the same odd-numbered rows or the same even-numbered rows are in a mirror image relationship with each other on the Y axis.

[0014] The beneficial effects of the present invention are as follows: the present invention adopts a combination of a four-pointed star-shaped unit and a double-arrow unit to form a two-dimensional unit cell structure, and designs a two-dimensional multi-cell structure with an adjustable Poisson's ratio according to different arrangement modes, thereby realizing a negative Poisson's ratio characteristic with a simple structure. When the material is subjected to tension or compression, each rod constituting the material undergoes axial elongation or shortening. Since the geometric parameters of each rod are adjustable, the macroscopic Poisson's ratio of the material changes between positive, near zero, and negative. The present invention can be applied to designs that improve structural safety and lightweight. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] 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.

[0016] Figure 1 Schematic diagram of the structure of the negative Poisson's ratio two-dimensional unit cell structure in Example 1; Figure 2 Schematic diagram of size parameters of the two-dimensional unit cell structure with negative Poisson's ratio in Example 1; Figure 3 Schematic diagram of the structure of the negative Poisson's ratio material in Example 2; Figure 4 is a graph showing the variation of the elongation of the negative Poisson's ratio material in the x direction with the angle θ in Example 2; Figure 5 is a graph showing the variation of the Poisson's ratio υ of the negative Poisson's ratio material in Example 2 with the angle θ; Figure 6 This is a schematic structural diagram of a two-dimensional unit cell structure with a negative Poisson's ratio in Example 3; Figure 7 Schematic diagram of the structure of the negative Poisson's ratio material in Example 4; Figure 8is a graph showing the variation of the elongation of the negative Poisson's ratio material in the x direction with the angle θ in Example 4; Fig. 9 is a graph showing the variation of the Poisson's ratio υ of the negative Poisson's ratio material in Example 4 with the angle θ; Markings in the figure: 100, four-pointed star unit, 101, four-pointed star body, 102, first V-shaped rod body, 103, first inner concave portion, 104, first connecting rod; 200, double-arrow unit, 201, double-arrow body, 202, second V-shaped rod, 203, arrow tip, 204, second inner concave portion, 205, second connecting rod; 300. Horizontal unit. DETAILED DESCRIPTION

[0017] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments, but they are not intended to limit the invention in any way.

[0018] Example 1: Figure 1 , 2 As shown, a negative Poisson's ratio two-dimensional unit cell structure, which belongs to a unilateral arrow configuration, includes a four-pointed star unit 100 and a double-arrow unit 200, wherein the four-pointed star unit 100 includes a four-pointed star body 101 and four first connecting rods 104 connected to the four-pointed star body 101. The four-pointed star body 101 is composed of four first V-shaped rods 102 of the same size, wherein the first V-shaped rod 102 is a V-shaped structure formed by connecting two straight rods of the same length, and the four first V-shaped rods 102 are connected along the circumferential direction through the connection of their open ends to enclose the four-pointed star body 101, and the tips of the first V-shaped rods 102 serve as the four corners of the four-pointed star body 101, and the connection between two adjacent first V-shaped rods 102 forms a concave first inner concave portion 103, so the four-pointed star body 101 has four first inner concave portions 103. The inner side of the first inner recess 103 points to the centroid of the four-pointed star-shaped body 101, and the outer side of the first inner recess 103 is also connected to the first connecting rod 104. The two opposite first connecting rods 104 in the four-pointed star-shaped unit 100 are on the same straight line passing through the centroid of the four-pointed star-shaped body 101, and the two adjacent first connecting rods 104 are perpendicular to each other.

[0019] The double-arrow unit 200 includes a double-arrow body 201 and a second connecting rod 205. The double-arrow body 201 is formed by combining and connecting two second V-shaped rods 202 of the same size. The second V-shaped rod 202 includes two straight rods of different lengths. One of the second V-shaped rods 202 uses the line connecting the two end points of the open end as the symmetry axis and is mirrored once to form the double-arrow body 201. One end of the double-arrow body 201 on the symmetry axis is a convex arrow tip 203, and the other end is a concave second inner recess 204. The second connecting rod 205 is connected to the outer side of the second inner recess 204, and the extension line of the second connecting rod 205 passes through the arrow tip 203.

[0020] When the four-pointed star unit 100 and the double-arrow unit 200 form the negative Poisson's ratio two-dimensional unit cell structure, the double-arrow unit 200 is arranged on one side of the four-pointed star unit 100, and the arrow tip 203 of the double-arrow body 201 in the double-arrow unit 200 is connected to the first connecting rod 104.

[0021] like Figure 2 As shown, a Cartesian rectangular coordinate system is established with the centroid of the four-pointed star-shaped body 101 as the coordinate origin, with the horizontal axis being the X-axis and the vertical axis being the Y-axis; the arrow tip 203 and the second inner recess 204 of the double-arrow unit 200 are both located on the Y-axis, and the vertices of the two second V-shaped rods 202 constituting the double-arrow body 201 respectively have the same horizontal coordinate as the ends of the first connecting rod 104 on the same side.

[0022] The specific size requirements of the negative Poisson's ratio two-dimensional unit cell structure in this embodiment are as follows: Figure 2 As shown, in the double-arrow unit 200, the structure is symmetrical about the Y axis. The two second V-shaped rods 202 constituting the double-arrow body 201 are respectively composed of straight rods CA and AD and straight rods CA′ and A′D. Points C and D are both located on the Y axis, wherein the lengths of straight rods AC and A′C are L1, and the lengths of straight rods AD and A′D are L2. The vertex angle of the second V-shaped rod 202 is ∠CAD, ∠CAD=α, and the arrow tip is ∠ADA′, ∠ADA′=β. The second connecting rod 205 is BC, and the length of BC is L4.

[0023] In the four-pointed star unit 100, the structure is symmetrical about the X-axis and the Y-axis. The four first V-shaped rods 102 are rods FEG, GIJ, JI′G′ and G′E′F, which are connected end to end around the origin of the coordinate system O to form a four-pointed star body. The length of the straight rods constituting the four first V-shaped rods is L3, that is, EF=EG=IG=IJ=I′J= I′G′=G′E′= E′F= L3, and the four corners of the four-pointed star body 101, that is, the vertex angles of the four first V-shaped rods 102 are equal, that is, ∠FEG=∠GIJ=∠JI′G′=∠G′E′F=θ. The four first connecting rods 104 are straight rods HG, DF, JK, and H′G′, and the straight rods HG and H′G′ are located on the X-axis and have a length of L4, and the straight rods DF and JK are located on the Y-axis and have a length of L5. In this way, vertices E and E′, vertices G and G′, vertices H and H′, and vertices I and I′ are symmetrical about the Y-axis, and vertices E and I, vertices F and J, and vertices E′ and I′ are symmetrical about the X-axis. The angles between the first connecting rod and the adjacent first V-shaped rod body 102 are equal, such as ∠DFE=γ. Therefore, θ+90°=2γ.

[0024] Vertex A and vertex H have the same X-axis coordinate, and vertex A′ and vertex H′ have the same X-axis coordinate, so as to realize the arrangement and connection between the two-dimensional unit cell structures with negative Poisson's ratio along the X-axis direction.

[0025] According to the symmetry relationship of the cell, the above-mentioned negative Poisson's ratio two-dimensional unit cell structure is symmetric about the Y axis as a whole.

[0026] Example 2 The negative Poisson's ratio material involved in this embodiment is a two-dimensional polyhedral structure obtained by periodically arranging the negative Poisson's ratio two-dimensional unit cell structure described in Example 1 in a plane.

[0027] Specifically, a plurality of negative Poisson's ratio two-dimensional unit cell structures are periodically arranged along the Y-axis direction, the ends of the first connecting rod and the second connecting rod located on the Y-axis in two adjacent negative Poisson's ratio two-dimensional unit cell structures are connected, and then repeatedly mirrored along the X-axis direction to obtain a two-dimensional polyhedral structure.

[0028] Next, numerical simulation is performed using ANSYS software to verify the negative Poisson's ratio characteristics of the metamaterial. The model size used has 6 layers of cells in the X-axis and Y-axis directions, that is, there are 6 negative Poisson's ratio two-dimensional unit cell structures on both the X-axis and the Y-axis. The structure is as follows: Figure 3 As shown in the figure, the unit type used is BEAM3. The overall bar of the model is made of Q235 alloy steel, that is, Young's modulus E 1= E 2 = 203Gpa, Poisson's ratio υ = 0.3, the cross-sectional area of ​​the rods constituting the cell is uniformly 0.1 × 0.1mm 2 of rectangular cross section, whereL 1 = 15 mm, L 2=17.3mm, L 3 = 12mm, L 4 = 8 mm, L 5 = 6.7mm, and the vertex angles θ of the four-pointed star-shaped body are 32°, 34°, 36°, 38°, and 40° respectively. When performing numerical simulation to solve the Poisson's ratio of the metamaterial shown, the longitudinal (Y-direction) elongation of the structure is set to 12mm, and the Poisson's ratio υ of the model is measured. The numerical simulation analysis results are shown in Figure 4 , 5 As shown, Figure 4 It is the graph of the material's transverse (X-direction) elongation Δx versus angle θ. Figure 5 is the graph of Poisson's ratio υ changing with angle θ. Figure 4 and Figure 5 It can be seen that within the adjustable range of angle θ, the overall lateral elongation of the structure decreases with the increase of angle θ, and the negative Poisson's ratio of the material weakens with the increase of angle θ, and both of them are approximately linear changes.

[0029] Example 3 This embodiment adjusts the negative Poisson's ratio two-dimensional unit cell structure on the basis of Embodiment 1 to obtain a negative Poisson's ratio two-dimensional unit cell structure having a structure different from the double-sided arrow configuration of Embodiment 1.

[0030] like Figure 6 As shown, in the negative Poisson's ratio two-dimensional unit cell structure of the double-sided arrow configuration, two double-arrow units 200 are arranged on opposite sides of the four-pointed star unit 100, and the arrow tips 203 in the two double-arrow units 200 are connected to the corresponding first connecting rods 104, and the two first connecting rods in the other direction of the four-pointed star unit 100 are used to connect with other four-pointed star units 100. Among them, the double-arrow unit 200 in this embodiment is no longer provided with a second connecting rod, and the remaining structural and dimensional parameters are the same as those in Example 1.

[0031] The negative Poisson's ratio two-dimensional unit cell structure of the double-sided arrow configuration is symmetrical about the X-axis and the Y-axis. In this embodiment, the two double-arrow units 200 are located in the Y-axis direction of the four-pointed star unit 100 and are connected to the first connecting rod 104 in the Y-axis direction. The two first connecting rods 104 in the X-axis direction are used to expand the negative Poisson's ratio two-dimensional unit cell structure in the X-axis direction.

[0032] Example 4 The negative Poisson's ratio material involved in this embodiment is a two-dimensional polyhedral structure obtained by periodically arranging the negative Poisson's ratio two-dimensional unit cell structure described in Example 3 in a plane.

[0033] Specifically, Figure 7As shown, multiple negative Poisson's ratio two-dimensional unit cell structures are periodically arranged along the X-axis direction to form a transverse unit 300. In the transverse unit 300, the ends of the two first connecting rods 104 located on the X-axis in two adjacent negative Poisson's ratio two-dimensional unit cell structures are connected, and the vertices of the second V-shaped rods 202 of the double-arrow unit are connected; then multiple rows of transverse units 300 are arranged along the Y-axis, and the adjacent rows of transverse units 300 are staggered along the X-axis by a certain distance to obtain a two-dimensional multi-cell structure, and the staggered distance is the length from the centroid of the star-shaped main body to the end of the first connecting rod 104 on the x-axis. In the two adjacent rows of staggered transverse units 300, the vertices of the second V-shaped rods 202 on the double-arrow unit 200 in one row of transverse units 300 are connected to the second inner concave portion 204 of the double-arrow unit 200 adjacent to it in the other row of transverse units 300. Therefore, the transverse units 300 in the same odd-numbered rows or the same even-numbered rows are mirror images of each other on the Y-axis.

[0034] The simulation test method described in Example 2 was used to perform numerical simulation using ANSYS software to verify the negative Poisson's ratio characteristics of the metamaterial. The model size used was a 4×3 structure, that is, the lateral unit in the X-axis direction had four negative Poisson's ratio two-dimensional unit cells, and there were three rows of lateral units in the Y-axis direction. The overall rod of the model was made of Q235 alloy steel, that is, Young's modulus E 1= E 2 = 203Gpa, Poisson's ratio υ = 0.3, the cross-sectional area of ​​the rods constituting the cell is uniformly 0.1 × 0.1mm 2 of rectangular cross section, where L 1 = 15 mm, L 2=17.3mm, L 3 = 12mm, L 4 = 8 mm, L 5 = 6.7mm, and the vertex angles θ of the four-pointed star-shaped body are 32°, 34°, 36°, 38°, and 40° respectively. When performing numerical simulation to solve the Poisson's ratio of the metamaterial shown, the longitudinal (Y-direction) elongation of the structure is set to 12mm, and the Poisson's ratio υ of the model is measured. The numerical simulation analysis results are shown in Figure 8 , 9 As shown, Figure 8 It is the graph of the material's transverse (X-direction) elongation Δx versus angle θ. Fig. 9 is the graph of Poisson's ratio υ changing with angle θ. Figure 8 and Fig. 9 It can be seen that within the adjustable range of angle θ, the overall lateral elongation of the structure decreases with the increase of angle θ, and the negative Poisson's ratio of the material weakens with the increase of angle θ, and both of them are approximately linear changes.

[0035] The negative Poisson's ratio two-dimensional unit cell structure of the present invention can adjust the macroscopic negative Poisson's ratio coefficient of the metamaterial by adjusting the length and angle of each straight rod of the basic structure, and realizes the negative Poisson's ratio characteristic with a simple structure. Therefore, the present invention effectively solves the problem of material damage or performance degradation caused by stress concentration in many engineering fields, and expands the types of metamaterials.

[0036] The above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Those skilled in the art should understand that the specific implementation modes of the present invention may be modified or replaced by equivalents with reference to the above embodiments. Any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention are within the scope of protection of the pending claims.

Claims

1. A two-dimensional unit cell structure with a negative Poisson's ratio, characterized in that: It includes connected four-pointed star-shaped units and double-arrow units; The four-pointed star unit includes a four-pointed star body, which is formed by four identical first V-shaped rods connected and surrounded in sequence through open ends, and the connection between two adjacent first V-shaped rods forms a first inner concave portion pointing to the centroid of the four-pointed star body, and the outer side of each first inner concave portion is also connected to a first connecting rod, and the extension line of each first connecting rod passes through the centroid of the four-pointed star body; The double-arrow unit comprises a double-arrow body, which is formed by a second V-shaped rod body with the line connecting the two end points of the open end as the symmetry axis and a mirror image, the two rod bodies of the second V-shaped rod body are of different lengths, one end of the double-arrow body on the symmetry axis is a convex arrow tip, and the other end is a second concave part, the outer side of the second concave part is connected to a second connecting rod, and the extension line of the second connecting rod passes through the arrow tip; The negative Poisson's ratio two-dimensional unit cell structure includes a single-sided arrow configuration and a double-sided arrow configuration. In the single-sided arrow configuration, one double-arrow unit is arranged on one side of the four-pointed star-shaped unit, and the arrow tip of the double arrow body in the double-arrow unit is connected to the first connecting rod; in the double-sided arrow configuration, two double-arrow units are arranged on opposite sides of the four-pointed star-shaped unit, and the arrow tips in the two double-arrow units are connected to the corresponding first connecting rods.

2. The negative Poisson's ratio two-dimensional unit cell structure according to claim 1, characterized in that: A Cartesian rectangular coordinate system is established with the centroid of the four-pointed star-shaped body as the coordinate origin, with the horizontal axis being the X-axis and the vertical axis being the Y-axis; the arrow tip and the second inner recess of the double-arrow unit are both located on the Y-axis, and the vertices of the two second V-shaped rods constituting the double-arrow body respectively have the same horizontal coordinate as the end of the first connecting rod on the same side.

3. The negative Poisson's ratio two-dimensional unit cell structure according to claim 2, characterized in that: The top angle of the first V-shaped rod is θ, the included angle between the first V-shaped rod and the adjacent first connecting rod is γ, and θ+90°=2γ.

4. A negative Poisson's ratio material, comprising a plurality of negative Poisson's ratio two-dimensional unit cell structures as claimed in claim 2 or 3, characterized in that: The negative Poisson's ratio two-dimensional unit cell structure is obtained by periodic arrangement in a plane to obtain a two-dimensional polyhedral structure.

5. A negative Poisson's ratio material according to claim 4, characterized in that: When the negative Poisson's ratio two-dimensional unit cell structure is a unilateral arrow configuration, multiple negative Poisson's ratio two-dimensional unit cell structures are periodically arranged along the Y-axis direction, the first connecting rod and the second connecting rod ends located on the Y-axis in two adjacent negative Poisson's ratio two-dimensional unit cell structures are connected, and then repeatedly mirrored along the X-axis direction to obtain a two-dimensional polyhedral structure.

6. A negative Poisson's ratio material according to claim 4, characterized in that: When the negative Poisson's ratio two-dimensional unit cell structure is a double-sided arrow configuration, multiple negative Poisson's ratio two-dimensional unit cell structures are periodically arranged along the X-axis direction to form transverse units, the two first connecting rod ends located on the X-axis in two adjacent negative Poisson's ratio two-dimensional unit cell structures are connected, and the vertices of the second V-shaped rod bodies of the double-arrow unit are connected; then multiple rows of transverse units are arranged along the Y-axis, and adjacent rows of transverse units are staggered along the X-axis by a certain distance to obtain a two-dimensional multicellular structure, and the staggered distance is the length from the centroid of the star-shaped main body to the end of the first connecting rod on the x-axis.

7. A negative Poisson's ratio material according to claim 6, characterized in that: The horizontal units in the same odd-numbered row or the same even-numbered row are mirror images of each other on the Y axis.

Images