CN115492886B - Three-dimensional honeycomb basic unit with negative poisson ratio characteristic, single-layer plate and structure - Google Patents

Abstract

The present invention discloses a three-dimensional honeycomb basic unit, a single-layer plate and a structure with negative Poisson's ratio characteristics, wherein the three-dimensional honeycomb basic unit includes a unit frame, an inclined rod A and a supporting rod A, the unit frame includes four basic cells, and the four basic three-dimensional honeycomb elements are connected end to end through connecting rods in sequence to form a frame of the basic unit, and the end points of the vertical rods of each basic cell extend out of the inclined rod A to converge to the connection point at the central axis inside the basic unit, and the connecting point is connected with the supporting rod A extending to the outside of the basic unit, and the inclined rod A connects the basic cells together to form a whole, thereby enhancing the integrity of the basic unit, so that each part of the basic unit can be deformed in a coordinated manner and uniformly stressed. It is composed of a number of three-dimensional honeycomb single-layer plates connected by supporting rods A and supporting rods B, and is more suitable for manufacturing plate-type or block-type materials or devices, and the structure has good stability and has negative Poisson's ratio effects in three directions.

Description

Three-dimensional honeycomb basic units, single-layer panels and structures with negative Poisson's ratio properties

Technical Field

The invention relates to the technical field of metamaterial structure design, and in particular to a three-dimensional honeycomb basic unit, a three-dimensional honeycomb single-layer plate and a three-dimensional honeycomb structure with negative Poisson's quotient characteristics.

Background Art

Negative Poisson's ratio materials and structures have different physical and mechanical properties from ordinary materials. They will expand laterally when subjected to axial tension and contract laterally when subjected to axial compression. Existing research results show that negative Poisson's ratio materials have good performance in energy absorption, vibration reduction, porous permeability, shear resistance and fracture resistance, and have broad application prospects in daily life and industrial production. For example, when a plate with negative Poisson's ratio characteristics is impacted, the nearby material will shrink toward the impact point, thereby absorbing more energy, reducing the diffusion of impact energy, and achieving the effect of energy absorption and vibration reduction. However, due to the imperfect and immature manufacturing and synthesis technology of negative Poisson's ratio materials, there are not many types of commonly used negative Poisson's ratio structures, especially three-dimensional negative Poisson's ratio structures are even rarer.

Summary of the invention

The object of the present invention is to provide a three-dimensional honeycomb basic unit with negative Poisson's quotient characteristics to solve the problems raised in the background technology.

To achieve the above object, the present invention provides a three-dimensional honeycomb basic unit with negative Poisson's quotient characteristics, including a unit frame, an oblique rod A and a supporting rod A, wherein the unit frame includes four basic cells distributed in a rectangular shape, wherein the basic cells are concave hexagonal cells, wherein the concave hexagonal cells include two parallel and symmetrical cell vertical rods and four cell oblique rods of equal length, wherein the top and bottom ends of the two cell vertical rods are respectively connected by two connected cell oblique rods, and the two cell oblique rods at the same end are inclined toward the inside of the hexagon; the four basic cells are sequentially connected head to tail by connecting rods; All connection points between the cell vertical rod and the cell diagonal rod are connected with diagonal rods A, and all diagonal rods A located at the top of the cell vertical rod are inclined downward and finally connected to the first connection point, and all diagonal rods A located at the bottom of the cell vertical rod are inclined upward and finally connected to the second connection point; the first connection point and the second connection point are both located on the longitudinal center line of the unit frame; the first connection point, the second connection point and each inner concave corner of the four basic cells are connected with support rods A, and the support rods A and the cell vertical rods are arranged parallel to each other.

Furthermore, the horizontal heights of the first connection point and the second connection point are respectively the same as the horizontal heights of the apex of the upper concave angle and the apex of the lower concave angle of the basic cell; the length of the support rod A is half the length of the cell vertical rod, and all the support rods A extend from the connection point to the outside of the unit frame.

Furthermore, the dimensions of the three-dimensional honeycomb basic unit should satisfy the following relationship:

β＝arctan(2tanθ)

Wherein, θ is the angle between the vertical bar and the diagonal bar of the concave hexagonal cell; β is the angle between the diagonal bar A and the vertical bar of the cell; a is the length of the diagonal bar of the cell; l is the length of the connecting rod.

Furthermore, the included angle between the cell vertical rod and the cell oblique rod is greater than or equal to 30° and less than 90°.

The present invention also provides a three-dimensional honeycomb single-layer plate with negative Poisson's ratio characteristics, including a single-layer plate skeleton, an inclined rod B and a supporting rod B, the single-layer plate skeleton includes a plurality of three-dimensional honeycomb basic units as described above, every three of the three-dimensional honeycomb basic units are arranged in a triangular form with the connecting rod as the side, these three-dimensional honeycomb basic units arranged in a triangular form are spliced to form the single-layer plate skeleton, the single-layer plate skeleton has a plurality of hexagonal star areas, the end points of the cell vertical rods of each basic cell forming the hexagonal star area are also connected with inclined rods B, and all the inclined rods B located at the top ends of the cell vertical rods are inclined downward and finally connected to the third connection point, and all the inclined rods B located at the bottom ends of the cell vertical rods are inclined upward and finally connected to the fourth connection point; the third connection point and the fourth connection point are both located on the longitudinal center line of the hexagonal star area; the third connection point and the fourth connection point are both connected with supporting rods B, and the supporting rods B and the cell vertical rods are arranged parallel to each other.

Furthermore, the length of the support rod B is half of the length of the cell vertical rod, and all the support rods B extend from the connection point to the outside of the hexagonal star area.

Furthermore, the angle between the oblique rod B and the cell vertical rod is equal to the angle between the oblique rod A and the cell vertical rod.

The present invention also provides a three-dimensional honeycomb structure with negative Poisson's tropy, comprising at least two layers of the three-dimensional honeycomb single-layer panels as described above, wherein two adjacent layers of the three-dimensional honeycomb single-layer panels are connected by the support rods A and B.

Compared with the prior art, the present invention has the following beneficial effects:

(1) A basic unit with negative Poisson's ratio characteristics of the present invention comprises a unit frame, an inclined rod A and a supporting rod A. Four basic cells are connected end to end by connecting rods to form a frame of the basic unit. The ends of the vertical rods of each basic cell extend out of the inclined rod A and converge to a connection point on the central axis inside the basic unit. The connecting point is connected to a supporting rod A extending to the outside of the basic unit. The frame of the basic unit, the inclined rod A and the supporting rod A together constitute a basic unit of a three-dimensional honeycomb structure with a negative Poisson's ratio. The inclined rod A connects the four basic cells together to form a whole, thereby enhancing the integrity of the basic unit and enabling various parts of the basic unit to deform in a coordinated manner and be evenly stressed.

(2) The three-dimensional honeycomb single-layer plate with negative Poisson's ratio of the present invention connects several basic units together through the inclined rod B, thereby enhancing the integrity and stability of the three-dimensional honeycomb single-layer plate, improving the stress performance of the three-dimensional honeycomb single-layer plate, and playing a role in coordinating the deformation of each basic unit.

(3) The three-dimensional honeycomb structure with negative Poisson's ratio characteristics of the present invention is composed of a plurality of three-dimensional honeycomb single-layer panels connected by support rods A and B. It is more suitable for manufacturing plate-type or block-type materials or devices. The structure has good stability and has a negative Poisson's ratio effect in three directions.

In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the embodiments of the present invention, but do not constitute a limitation on the embodiments of the present invention. In the accompanying drawings:

FIG1 is a schematic diagram of the structure of a basic cell (concave hexagonal cell) in the present invention;

FIG2 is a schematic diagram of the structure of a basic unit in the present invention;

FIG3 is a top view of the basic unit in FIG2 ;

Fig. 4 is a front view of the basic unit in Fig. 2;

FIG5 is a schematic diagram of the structure of a three-dimensional honeycomb structure single-layer plate having negative Poisson's ratio characteristics according to the present invention;

FIG6 is a top view of the three-dimensional honeycomb structure single-layer plate in FIG5 ;

Among them: 1-basic cell; 1.1-cell vertical rod; 1.2-cell oblique rod; 2-connecting rod; 3-oblique rod A; 4-support rod A, 5-oblique rod B; 6-support rod B; M-three-dimensional honeycomb basic unit; N-three-dimensional honeycomb single-layer plate.

DETAILED DESCRIPTION

The embodiments of the present invention are described in detail below with reference to the accompanying drawings, but the present invention can be implemented in many different ways as defined and covered by the claims.

Referring to FIG. 1 , this embodiment provides a three-dimensional honeycomb basic unit with negative Poisson's ratio characteristics, including a unit frame, an inclined rod A and a supporting rod A, and the specific structure is as follows:

The unit frame includes four basic cells 1 distributed in a rectangular shape, and the basic cell 1 is a concave hexagonal cell. As shown in Figure 1, the concave hexagonal cell includes two cell vertical rods 1.1 and four cell oblique rods 1.2. The two cell vertical rods 1.1 are equal in length and parallel to each other on the left and right. The four cell oblique rods 1.2 are equal in length. The four cell oblique rods are divided into two groups, upper and lower. The two cell oblique rods in each group are connected to form an inwardly concave angle that is concave toward the inner side of the hexagon. After the two cell oblique rods in each group are connected, they are respectively connected to the upper and lower ends of the two cell oblique rods, so the two inwardly concave angles are relatively arranged at the upper and lower ends of the concave hexagonal cell. Preferably, the angle 30°≤θ between the cell vertical rods 1.1 and the cell oblique rods 1.2 of the concave hexagonal cell is less than 90°.

As shown in Figures 2 to 4, four basic cells 1 are connected end to end by connecting rods 2 in sequence to form a unit frame. Specifically, the upper and lower ends of each cell vertical rod 1.1 are connected to the upper and lower ends of the cell vertical rod close to it in another basic cell through a connecting rod 2, that is, two adjacent cell vertical rods in different basic cells are connected by two connecting rods, and the two ends of one connecting rod are respectively connected to the top of the two cell vertical rods, and the two ends of the other connecting rod are respectively connected to the lower ends of the two cell vertical rods. All connection points of the cell vertical rod 1.1 and the cell oblique rod 1.2 are connected with oblique rods A3, and all oblique rods A3 connected to the top of the cell vertical rod are tilted downward and finally connected to the first connection point, and all oblique rods A3 connected to the bottom of the cell vertical rod are tilted upward and finally connected to the second connection point. These first connection points and second connection points are both located on the longitudinal center line of the unit frame. A support rod A4 is connected to each of the first connection point, the second connection point and each inner concave corner of the four basic cells, and the support rod A4 is arranged parallel to the cell vertical rod. In this structural setting, the basic unit frame 1, the inclined rod A3 and the support rod A4 together form a basic unit of the negative Poisson's ratio three-dimensional honeycomb structure, and the inclined rod A3 connects the four basic cells 1 together to form a whole, which enhances the integrity of the basic unit and enables each part of the basic unit to coordinate deformation and evenly bear force.

In a specific embodiment, the horizontal heights of the first connection point and the second connection point are respectively the same as the horizontal heights of the apex of the upper concave angle and the apex of the lower concave angle of the basic cell; the length of the support rod A4 is half the length of the cell vertical rod 1.1, and all support rods A4 extend from the connection point to the outside of the unit frame.

In a specific embodiment, in order to coordinate the deformation of the components of the basic unit, the size of the three-dimensional honeycomb basic unit should satisfy the following relationship:

β＝arctan(2tanθ)

Wherein, θ is the angle between the vertical bar and the diagonal bar of the concave hexagonal cell; β is the angle between the diagonal bar A and the vertical bar of the cell; a is the length of the diagonal bar of the cell; l is the length of the connecting rod.

As shown in Figures 5 and 6, this embodiment also provides a three-dimensional honeycomb single-layer plate with negative Poisson's ratio characteristics, including a single-layer plate skeleton, an inclined rod B and a supporting rod B. The single-layer plate skeleton includes a number of three-dimensional honeycomb basic units M as described above, and each three three-dimensional honeycomb basic units are arranged in a triangular form with a connecting rod 2 as an edge to form a three-dimensional honeycomb basic unit group. Several such three-dimensional honeycomb basic unit groups are finally spliced to form a single-layer plate skeleton, and the single-layer plate skeleton has a number of hexagonal star regions. The end points of the upper and lower ends of the cell vertical rods of each basic cell enclosing the hexagonal star region are also connected to inclined rods B5, and all inclined rods B located at the top of the cell vertical rods are tilted downward and finally connected to the third connection point, and all inclined rods B located at the bottom of the cell vertical rods are tilted upward and finally connected to the fourth connection point; the third connection point and the fourth connection point are both located on the longitudinal center line of the hexagonal star region. Support rods B6 are connected to the third connection point and the fourth connection point, and the support rods B and the cell vertical rods are arranged parallel to each other. In this structural setting, the length of the support rod B6 is half the length of the cell vertical rod 1.1, and all the support rods B extend from the corresponding connection points to the outside of the hexagonal star area. The oblique rods B connect the basic units together, enhance the integrity and stability of the three-dimensional honeycomb single-layer board, improve the stress performance of the three-dimensional honeycomb single-layer board, and play a role in coordinating the deformation of each basic unit.

This embodiment also provides a three-dimensional honeycomb structure with negative Poisson's ratio characteristics, including at least two layers of three-dimensional honeycomb single-layer panels N as described above, and two adjacent layers of three-dimensional honeycomb single-layer panels are connected by support rods A4 and support rods B6. In order to coordinate the deformation of the components of the three-dimensional honeycomb structure, the dimensions of the above components should meet the following conditions: 1) the support rods A4 and B6 have the same length; 2) the angle between the oblique rod B5 and the cell vertical rod 1.1 is equal to the angle between the oblique rod A and the cell vertical rod.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims (8)

1. The three-dimensional honeycomb basic unit with the negative poisson ratio characteristic is characterized by comprising a unit frame, inclined rods A and supporting rods A, wherein the unit frame comprises four basic cells which are distributed in a rectangular shape, the basic cells are concave hexagonal cells (1), each concave hexagonal cell comprises two cell vertical rods (1.1) which are symmetrical in parallel and four cell inclined rods (1.2) which are equal in length, the top ends and the bottom ends of the two cell vertical rods are respectively connected through the two connected cell inclined rods, and the two cell inclined rods at the same end are inclined inwards towards a hexagon; the four basic cells are connected end to end sequentially through a connecting rod (2); the cell vertical rods and all connection points of the cell diagonal rods are connected with diagonal rods A (3), all diagonal rods A positioned at the top ends of the cell vertical rods incline downwards and are finally connected with a first connection point, and all diagonal rods A positioned at the bottom ends of the cell vertical rods incline upwards and are finally connected with a second connection point; the first connection point and the second connection point are both located on a longitudinal centerline of the unit frame; the first connecting point, the second connecting point and each concave angle of the four basic cells are connected with a supporting rod A (4), and the supporting rods A and the cell vertical rods are arranged in parallel.

2. The three-dimensional cellular base unit of claim 1, wherein the first connection point and the second connection point have the same level as the top and bottom concave corners of the base unit, respectively; the length of the supporting rods A is half of the length of the cell vertical rods, and all the supporting rods A extend from the connecting points to the outer side of the unit frame.

3. The three-dimensional cellular base unit according to claim 1, characterized in that the dimensions of the three-dimensional cellular base unit should satisfy the following relation:

β＝arctan(2tanθ)

Wherein θ is the angle between the vertical cell rod and the diagonal cell rod in the concave hexagonal cell; beta is the included angle between the inclined rod A and the cell vertical rod; a is the length of the cell diagonal; l is the length of the connecting rod.

4. The three-dimensional cellular base unit according to claim 1, wherein the angle between the cell vertical bars and the cell diagonal bars is 30 ° or more and less than 90 °.

5. A three-dimensional honeycomb single-layer board with negative poisson ratio characteristics, which is characterized by comprising a single-layer board framework, inclined rods B and supporting rods B, wherein the single-layer board framework comprises a plurality of three-dimensional honeycomb basic units (M) as claimed in any one of claims 1-4, each three-dimensional honeycomb basic units are arranged in a triangular form with connecting rods (2) as sides and spliced to form the single-layer board framework, the single-layer board framework is internally provided with a plurality of hexagonal star areas, the end points of the cell vertical rods of all basic cells surrounding the hexagonal star areas are also connected with inclined rods B (5), all the inclined rods B positioned at the top ends of the cell vertical rods are downwards inclined and finally connected with a third connecting point, and all the inclined rods B positioned at the bottom ends of the cell vertical rods are upwards inclined and finally connected with a fourth connecting point; the third connection point and the fourth connection point are both positioned on the longitudinal central line of the hexagonal star region; and the third connecting point and the fourth connecting point are both connected with a supporting rod B (6), and the supporting rod B and the cell vertical rods are mutually parallel.

6. The three-dimensional cellular single-layer board according to claim 5, characterized in that the length of the supporting bars B is half the length of the cell vertical bars, all the supporting bars B extending from the connection point to the outside of the hexagonal area.

7. The three-dimensional cellular single-layer board according to claim 5, characterized in that the angle between the diagonal B and the cell vertical bar is equal to the angle between the diagonal a and the cell vertical bar.

8. A three-dimensional honeycomb structure having negative poisson's ratio characteristics, characterized by comprising at least two layers of three-dimensional honeycomb single-layer sheets (N) according to any one of claims 5 to 7, adjacent two layers of said three-dimensional honeycomb single-layer sheets being connected by means of said support bars a and B.