CN109334139B

CN109334139B - Lattice structure and unit structure thereof, and lattice sandwich structure

Info

Publication number: CN109334139B
Application number: CN201811435722.4A
Authority: CN
Inventors: 冯雪; 付浩然
Original assignee: Tsinghua University; Institute of Flexible Electronics Technology of THU Zhejiang
Current assignee: Tsinghua University
Priority date: 2018-11-28
Filing date: 2018-11-28
Publication date: 2021-05-04
Anticipated expiration: 2038-11-28
Also published as: CN109334139A

Abstract

The invention relates to a lattice structure, a unit structure thereof and a lattice sandwich structure. The unit structure comprises a first base, a second base and a connecting rod for connecting the first base and the second base; the included angle between the connecting rod and the horizontal plane is set to be theta, theta is more than or equal to 40 degrees and less than or equal to 50 degrees, wherein: the length of the connecting rod is L, the width of the cross section of the connecting rod along the vertical plane perpendicular to the central axis of the connecting rod is W, the thickness of the cross section of the connecting rod along the vertical plane perpendicular to the central axis of the connecting rod is T, the T is less than or equal to W, and the W/L is less than or equal to 0.1 and less than or equal to 0.15. The unit structure of the invention has small plastic strain, the adjustment of an energy absorption curve can be realized through the design of the parameters of the unit structure, and the unit structure can be restored to be deformed through the action of external force and can be repeatedly used, thereby expanding the application range of the lattice structure and the lattice sandwich structure which are spliced by the lattice units.

Description

Lattice structure and unit structure thereof, and lattice sandwich structure

Technical Field

The invention relates to the technical field of energy-absorbing materials, in particular to a lattice structure, a unit structure thereof and a lattice sandwich structure.

Background

The energy-absorbing material has wide application in personnel protection, building shock absorption, impact resistance of automobiles and airplanes and protection of precise parts. Traditional energy-absorbing materials include square thin-walled beams, corrugated tubes, honeycomb structural materials, egg-box structural materials, foam metal materials, lattice materials, and the like.

The square thin-wall beam is simple in structure, strong in energy absorption capacity and widely applied to collision energy absorption of automobiles. As shown in fig. 1, when an impact load is applied, the square thin-walled beam is laterally flexed, so that the metal material is plastically deformed, and the impact force is absorbed. The square thin-wall beam can adjust the energy absorption capacity of the structure by adjusting a welding method, wall thickness, cross section, pre-deformation and the like. However, since plastic strain is introduced into the metal during the deformation of the structure, the deformation process is not reversible and the structure cannot be reused after being subjected to a single impact load.

The egg-box type structural material is prepared from various alloys through hot stamping or cold stamping, and the energy absorption capacity of the egg-box type structural material is related to the geometric shape of the egg-box type structural material. Its deformation along the load-bearing direction over a small length can absorb a large amount of energy. Under impact load, its energy absorption rate can be expressed as a function of the section size as a variable. Then, in a specific application, the cross-sectional dimension can be optimized as required to obtain the cross-sectional shape with the best energy absorption. Studies have shown that the larger the cone angle, the higher the energy absorption rate of the egg-box type structural material, but on the other hand, the larger the cone angle, the more difficult the punch forming of the egg-box type structural material, because the larger the cone angle, the greater the possibility of the steel plate cracking during the punching process.

The foam metal material has the characteristics of bearing large deformation and maintaining relatively constant stress under the action of compressive load, and has the characteristics of light weight and the like, so that the foam metal material is widely applied to anti-collision structures and explosion-proof structures. As shown in FIG. 2a, the holes of the open-cell foam metal material are connected by the hole edges and are communicated with each other, so that the air permeability is good, and the heat exchange and dissipation capacity and the filtering and separating capacity are good. The main preparation method is that firstly a porous prefabricated part is obtained, and then the porous prefabricated part is utilized to carry out processes of seepage, deposition, sintering and the like, and finally the open-cell foam metal material is obtained. The open-cell foam metal material is characterized by controllable structure, but the preparation process is more complex and is not easy to realize large-scale production. As shown in fig. 2b, the closed-cell metal foam material has pore walls in addition to the connection between pores and edges, and the pores are approximately spherical circular pores with high porosity and large specific surface area. Compared with a solid structure, the closed-cell foamed aluminum has high specific strength and specific rigidity and a longer compression stroke due to the existence of air holes. The preparation is relatively simple and can be directly obtained by a foaming process, and comprises the following steps: melt foaming, direct blowing foaming, solid-gas eutectic solidification, Powder Compaction Melting (PCM) and the like. However, in the deformation process of the structure, plastic strain is introduced into metal, so that the deformation process is irreversible, and after the structure bears once impact load, the impact resistance of the structure is greatly reduced, and even the structure cannot be reused completely.

The lattice material is a space lattice ordered porous material consisting of nodes and connecting rod units, and has the characteristics of good vibration damping performance, strong designability and the like. When the lattice material is impacted, the impact energy is converted into the strain energy through large-range plastic deformation, so that a large amount of impact energy can be absorbed, and the impact protection efficiency is improved. The stress-strain curve of the tetrahedral lattice material after being pressed is shown in fig. 3, and it can be known from fig. 3 that the structure has a stable structure of only an initial structure all the time in the compression process because the stress of the structure is always greater than 0, and when bearing a great impact load, the structure can generate a great plastic deformation, and the impact resistance can be greatly reduced.

Therefore, although the square thin-wall energy-absorbing beam, the egg-box type structural material, the foam metal material and the lattice material have good energy-absorbing characteristics, the defects of irreversible deformation and difficult preparation exist, and the application range and the repeatability of the energy-absorbing material are greatly limited.

Disclosure of Invention

Based on the above, it is necessary to provide a lattice structure, a unit structure thereof, and a lattice sandwich structure for energy-absorbing materials; the unit structure of the lattice structure has small plastic strain, the energy absorption curve can be adjusted through the design of the parameters of the unit structure, and the unit structure can be restored to be deformed through the action of external force and can be repeatedly used, so that the application range of the lattice structure and the lattice sandwich structure formed by splicing the lattice units is expanded.

A unit structure based on a lattice structure, the unit structure comprising a first base, a second base, and a connecting rod connecting the first base and the second base;

the included angle between the connecting rod and the horizontal plane is set to be theta, theta is more than or equal to 40 degrees and less than or equal to 50 degrees, wherein:

the length of the connecting rod is L, the width of the cross section of the connecting rod along the vertical plane perpendicular to the central axis of the connecting rod is W, the thickness of the cross section of the connecting rod along the vertical plane perpendicular to the central axis of the connecting rod is T, the T is less than or equal to W, and the W/L is less than or equal to 0.1 and less than or equal to 0.15.

In one embodiment, the connecting rod structure comprises one of a cylindrical structure and a prismatic structure.

In one embodiment, the prism structure is a quadrangular prism structure.

In one embodiment, the connecting rod is provided with a reinforcing part on the periphery side, and the length of the reinforcing part along the length extending direction of the connecting rod is L₁A width W of a cross section perpendicular to the vertical plane₁Wherein, L is more than or equal to 0.05₁/L≤0.15，1.1≤W₁/W≤1.2。

In one embodiment, the connecting rod is provided with the reinforcing part at a position close to the first base or the second base, and the distance between the reinforcing part and the adjacent first base or second base along the length direction of the connecting rod is d, wherein d/L is more than or equal to 0.1 and less than or equal to 0.3.

In one embodiment, the number of the reinforcing parts is multiple, and the plurality of the reinforcing parts are arranged at intervals.

In one embodiment, the connecting rod is provided with one reinforcing part at a position close to the first base and the second base respectively.

In one embodiment, the first base and/or the second base includes a connecting seat and a connecting part protruding from the connecting seat, and the connecting rod intersects with the connecting part.

In one embodiment, the connecting portion includes a connecting surface for connecting the link, and the link is perpendicular to the connecting surface.

In one embodiment, a cross-sectional shape of the connecting portion along the vertical plane includes one of a partial circle, a triangle, and a trapezoid.

In one embodiment, the connecting seat is provided with a splicing structure which is used for splicing and fixing the connecting seat with different unit structures; and/or

The splicing structure is used for being spliced and fixed with an external mechanism.

In one embodiment, the unit structure is a unitary structure.

In the unit structure of the lattice structure, through the design of parameters, the unit structure has two stable structures, wherein one stable structure is a structure when the unit structure is not deformed initially, namely a first stable structure, and the other stable structure is a structure corresponding to a minimum value of strain energy of the unit structure, namely a second stable structure. Under these two stable structure, remove external effort, the cell structure can not take place deformation, and the structure is fixed. And after the unit structure is pressed, in the process of converting the unit structure from the first stable structure to the second stable structure, the unit structure absorbs a large amount of energy which is equal to the difference value of the strain energy of the two stable structures, so that the plastic strain of the unit structure can be reduced. And after the unit structure is plastically deformed within the plastic deformation range, the unit structure can be restored to be deformed under the action of external force, so that the repeated use is realized.

In addition, through the adjustment of the parameters of the unit structure, the strain energy minimum value of the second stable structure of the unit structure can be changed, so that the adjustment of an energy absorption curve of the unit structure can be realized, and different use requirements can be met.

The lattice structure is formed by splicing a plurality of unit structures.

In one embodiment, the connecting rods of a plurality of lattice structures are spliced to form at least one of a pyramid lattice structure, a Kagome lattice structure, a tetrahedral lattice structure and a fishing net lattice structure.

In one embodiment, in the fishing net-shaped lattice structure, reinforcing rods are arranged at the positions of intersecting nodes between unit structures or at positions right below the intersecting nodes.

The lattice structure is formed by arraying and splicing the unit structures, so that the lattice structure can absorb large-area impact energy, the plastic deformation of the lattice structure is reduced, and the lattice structure can be restored to the original state and reused through external force after deformation.

The lattice sandwich structure comprises a first cover plate, a second cover plate and a lattice structure, wherein the second cover plate is arranged opposite to the first cover plate, and the lattice structure is arranged between the first cover plate and the second cover plate.

The lattice sandwich structure can absorb large-area impact energy, reduce plastic deformation, can restore the original shape and be repeatedly used through the action of external force after deformation, and can be widely applied to the fields of personnel protection, building shock absorption, impact resistance of automobiles and airplanes, protection of precise parts and the like.

Drawings

FIG. 1 is a schematic diagram of a deformation process of a square thin-walled beam;

fig. 2 is a schematic view of a macroscopic morphology of a metal foam material, wherein a is an open-cell metal foam material: b is a closed cell foam metal material;

FIG. 3 is a stress-strain curve diagram of a tetrahedral lattice material under pressure, wherein a is a stress-strain curve of a test piece 1, b is a stress-strain curve of a test piece 2, c is a stress-strain curve of a test piece 3, and d is a numerical simulation curve;

FIG. 4 is a schematic structural view of a cell structure of embodiment 1;

FIG. 5 is a schematic structural view of a connecting rod in the unit structure shown in FIG. 4;

FIG. 6 is a schematic view of the compressed cell structure of FIG. 4;

FIG. 7 is a force-displacement graph of the cell structure of the first parameter shown in FIG. 4 under compression;

FIG. 8 is a strain energy-displacement graph of the cell structure under pressure for the first parameter shown in FIG. 4;

FIG. 9 is a force-displacement graph of the cell structure of the second parameter shown in FIG. 4 under compression;

FIG. 10 is a strain energy-displacement graph of the cell structure under pressure for the second parameter shown in FIG. 4;

FIG. 11 is a force-displacement graph of the cell structure of the third parameter shown in FIG. 4 under compression;

FIG. 12 is a strain energy-displacement graph of the cell structure under pressure for the third parameter shown in FIG. 4;

FIG. 13 is a force-displacement graph of the fourth parameter of FIG. 4 under compression of the cell structure;

FIG. 14 is a graph of strain energy versus displacement for the fourth parameter of the cell structure of FIG. 4 under pressure;

FIG. 15 is a force-displacement graph of the fifth parameter of FIG. 4 under compression of the cell structure;

FIG. 16 is a strain energy-displacement graph of the cell structure under pressure for the fifth parameter shown in FIG. 4;

FIG. 17 is a schematic structural view of a cell structure of embodiment 2;

FIG. 18 is a force-displacement graph of the cell structure under compression for one of the parameters shown in FIG. 17;

FIG. 19 is a graph of strain energy versus displacement for the cell structure of a parameter shown in FIG. 18 under pressure;

FIG. 20 is a schematic structural view of a cell structure of embodiment 3;

FIG. 21 is an assembly view of the unit structure of embodiment 3;

fig. 22 is a schematic structural diagram of the lattice sandwich structure of example 4, in which the lattice structure of fig. 22a is a fishing net-like structure, the lattice structure of fig. 22b is a Kagome lattice structure, and the lattice structure of fig. 22c is a pyramid lattice structure.

In the figure: 1. a unit structure; 2. a first cover plate; 3. a second cover plate; 10. a first base; 11. a connecting rod; 12. a second base; 13. a reinforcing bar; 100. a connecting portion; 101. a connecting seat; 102. a reinforcing portion; 103. and (5) splicing the structure.

Detailed Description

The lattice structure, unit structure thereof and lattice sandwich structure provided by the present invention will be further described by the following specific examples.

Example 1:

as shown in fig. 4 and 5, the unit structure 1 based on the lattice structure provided by the present embodiment includes a first base 10, a second base 12, and a link 11 connecting the first base 10 and the second base 12.

And in a normal placing state, an included angle between the connecting rod and the horizontal plane is set as theta. The length of the connecting rod is L, the width of the cross section of the connecting rod along the vertical plane perpendicular to the central axis of the connecting rod is W, and the thickness of the cross section of the connecting rod along the vertical plane perpendicular to the central axis of the connecting rod is T.

Let θ be 45 °, W/L be 0.12, and T ≦ W be the first parameter design of the connecting rod 11 in this embodiment. In this case, the bar 11 is an euler-bernoulli beam, and is analyzed by a numerical simulation method (plane strain model). After the unit structure 1 of the present embodiment is pressed, the connecting rod 11 deforms in the vertical plane where the central axis is located, the schematic structural diagram is shown in fig. 6, the force-displacement curve is shown in fig. 7, and the strain energy-displacement curve is shown in fig. 8. As can be seen from the figure, the force-displacement curve of the unit structure 1 has a partial region where the applied force is less than 0, and the strain energy in the strain energy-displacement curve has a minimum point in the region where the applied force returns from less than 0 to 0 or more. Therefore, the unit structure 1 can have two stable structures, wherein one stable structure is a structure when the unit structure 1 is not initially deformed, i.e., a first stable structure, and the other stable structure is a structure corresponding to the minimum value of the strain energy of the unit structure 1, i.e., a second stable structure. Under these two stable structure, remove external effort, unit structure 1 all can not take place deformation, and the structure is fixed.

At this time, in the process of the unit structure 1 being transformed from the first stable structure to the second stable structure after being compressed, the unit structure 1 will absorb a large amount of energy, which is equal to the difference between the strain energies of the two stable structures, and thus, the plastic strain of the unit structure 1 can be reduced. After plastic deformation, the unit structure 1 can be restored to be deformed by external force such as direct hand pulling, mechanical testing instruments (such as a stretching machine) and the like, so that repeated use is realized.

Taking the second parameter design of the connecting rod 11 of the present embodiment as an example, where θ is 40 °, W/L is 0.12, and T ≦ W, analysis is performed by using a numerical simulation method (plane strain model). The force-displacement curve is shown in fig. 9, and the strain energy-displacement curve is shown in fig. 10. As can be seen from the figure, the region of the force-displacement curve of the unit structure 1 in which the applied force is less than 0 is almost disappeared, and the strain energy minimum point in the strain energy-displacement curve is also almost disappeared.

Taking the third parameter design of the connecting rod 11 of the present embodiment as an example, where θ is 50 °, W/L is 0.12, and T ≦ W, analysis is performed by using a numerical simulation method (plane strain model). The force-displacement curve is shown in fig. 11, and the strain energy-displacement curve is shown in fig. 12. As can be seen from the figure, the region of the force-displacement curve of the unit structure 1 in which the applied force is less than 0 is almost disappeared, and the strain energy minimum point in the strain energy-displacement curve is also almost disappeared.

Taking the fourth parameter design of the connecting rod 11 of the present embodiment as an example, where θ is 45 °, W/L is 0.1, and T ≦ W, analysis is performed by using a numerical simulation method (plane strain model). The force-displacement curve is shown in fig. 13, and the strain energy-displacement curve is shown in fig. 14. As can be seen from the figure, the region of the force-displacement curve of the unit structure 1 in which the applied force is less than 0 is almost disappeared, and the strain energy minimum point in the strain energy-displacement curve is also almost disappeared.

Taking θ as 45 °, W/L as 0.15, and T ≦ W as an example of the fifth parameter design of the connecting rod 11 according to this embodiment, analysis was performed by a numerical simulation method (plane strain model). The force-displacement curve is shown in fig. 15, and the strain energy-displacement curve is shown in fig. 16. As can be seen from the figure, the region of the force-displacement curve of the unit structure 1 in which the applied force is less than 0 is almost disappeared, and the strain energy minimum point in the strain energy-displacement curve is also almost disappeared.

Therefore, the connecting rod 11 satisfies the conditions that theta is more than or equal to 40 degrees and less than or equal to 50 degrees, T is less than or equal to W, and W/L is more than or equal to 0.1 and less than or equal to 0.15, so that the unit structure 1 has two stable structures. Therefore, the unit structure 1 can be made to have small plastic strain, and after plastic deformation, the unit structure 1 can be restored to be deformed by the action of external force, thereby realizing repeated use.

Meanwhile, the minimum value of the strain energy of the second stable structure of the unit structure 1 can be changed by adjusting the parameters of the connecting rod 11 of the unit structure 1, so that the adjustment of the energy absorption curve of the unit structure 1 can be realized.

It is understood that the unit structure 1 is not limited by the placing manner and the placing state when being assembled and applied, and a certain reference surface in the structure can be used as a horizontal plane.

Specifically, the connecting rod 11 structure includes one of a cylindrical structure and a prismatic structure. When the connecting rod is in a cylindrical structure, T is equal to W.

Wherein the prism structure comprises a triangular prism structure, a quadrangular prism structure, a pentagonal prism structure and the like, and preferably the quadrangular prism structure. In the quadrangular structure, the bottom surface of the quadrangular structure is preferably rectangular or square, so that the quadrangular structure satisfies T ≦ W.

Specifically, the first base 10 includes a connecting seat 101 and a connecting portion 100 protruding from the connecting seat 101, and the connecting rod 11 intersects with the connecting portion 100.

The second base 12 may also include a connecting portion 101 and a connecting portion 100 protruding from the connecting portion 101, and the connecting rod 11 intersects with the connecting portion 100.

Wherein a shape of a cross section of the connection part 100 along the vertical plane includes one of a partial circle, a triangle, and a trapezoid.

The connecting portion 100 includes a connecting surface for connecting the link 11, and the link 11 is perpendicular to the connecting surface. Therefore, when the whole unit structure 1 is deformed under stress, the stress concentration caused by the excessively small included angle between the connecting rod 11 and the connecting surface can be prevented, and the whole unit structure 1 is damaged.

It is understood that on the connecting portion 100, a plurality of links 11 may be provided in different directions. For example, when the cross section of the connecting portion 100 along the vertical plane is triangular, correspondingly, the connecting portion 100 is a rectangular pyramid structure, at this time, four inclined planes of the rectangular pyramid can all serve as connecting surfaces of the connecting portion 100 for connecting the connecting rods 11, the connecting rods 11 can be respectively arranged on the four connecting surfaces, and all the connecting rods 11 can be perpendicular to the connecting surfaces.

The connecting base 101 is used for connecting and fixing different unit structures 1 with each other, or can also be used for connecting and fixing with an external mechanism. The connection means may be welding, adhesive bonding, or the like. The external structure can be a cover plate of a dot matrix sandwich structure and the like.

The shape of the section of the connection holder 101 along the vertical plane may be rectangular.

Specifically, the material of the unit structure 1 may be a high molecular polymer, a metal material, or the like. When the material is a high-molecular polymer, the unit structure 1 can be produced and prepared in a 3D printing mode, only a design drawing needs to be input, and the process flow is simple. When the material is a metallic material, the unit structure 1 can be produced by investment casting, press-and-fold brazing, or the like.

Specifically, the unit structure 1 is an integral structure. Therefore, the intersection of the link 11 and the first and

second bases

10 and 12 in the unit structure 1 is structurally stable.

Example 2:

as shown in fig. 17, in the present embodiment, in addition to embodiment 1, a reinforcing portion 102 is provided on the peripheral side of the connecting rod 11, and the reinforcing portion 102 is used for locally adjusting the energy absorption curve of the unit structure 1.

The length of the reinforcing part 102 in the longitudinal direction of the link 11 is L₁A width W of a cross section perpendicular to the vertical plane₁Wherein, L is more than or equal to 0.05₁/L≤0.15，1.1≤W₁/W≤1.2。

Theta is 45 degrees, W/L is 0.1, T is less than or equal to W, L₁/L＝0.5，W₁The parameter design of the connecting rod 11 of this embodiment is given as an example at 1.1,/W is analyzed by a numerical simulation method (plane strain model). The force-displacement curve is shown in fig. 18, and the strain energy-displacement curve is shown in fig. 19. As can be seen from comparison with fig. 13 and 14, the reinforcement 102 can be used to locally adjust the energy absorption curve of the cell structure 1.

Specifically, the reinforcing part 102 is disposed at a position of the connecting rod 11 close to the first base 10 or the second base 12, and a distance d between the reinforcing part 102 and the adjacent first base 10 or the second base 12 along the length direction of the connecting rod 11 is set, wherein d/L is greater than or equal to 0.1 and less than or equal to 0.3.

Specifically, the number of the reinforcing portions 102 is plural, and the plural reinforcing portions 102 are provided at intervals.

It is understood that, according to the use requirement, a plurality of the reinforcing portions 102 may be disposed at positions close to the first base 10; alternatively, a plurality of the reinforcement portions 102 are each provided at a position close to the second base 12; alternatively, a plurality of the reinforcement portions 102 are provided at positions close to the first base 10 and the second base 12, respectively.

As shown in fig. 17, in this embodiment, the link 11 is provided with one reinforcing portion 102 at each position near the first base 10 and the second base 12.

Further, the length of the plurality of reinforcing portions 102 in the longitudinal direction of the link 11 is L according to the use requirement₁A width W of a cross section perpendicular to the vertical plane₁The distance d between the plurality of reinforcing portions 102 and the adjacent first base 10 or second base 12 along the length direction of the link 11 may be different.

Example 3:

as shown in fig. 20, in this embodiment, on the basis of embodiment 1, the connection seats 101 are respectively provided with a splicing structure 103, and the splicing structures 103 are used for splicing and fixing with different unit structures 1, or the splicing structures 103 can also be used for splicing and fixing with an external mechanism.

The splicing structures 103 are insertion parts or groove parts capable of being matched with the insertion parts to be clamped, and the splicing structures 103 spliced with each other are designed in a matched mode.

Specifically, the splicing structure 103 provided on the connection seat 101 of the first base 10 of one unit structure 1 may be engaged with the splicing structure 103 provided on the connection seat 101 of the first base 10 of another unit structure 1, or may be engaged with the splicing structure 103 provided on the connection seat 101 of the second base 12 of another unit structure 1. For example, four unit structures 1 may be assembled and fixed to each other by the assembling structure 103 to form a structure as shown in fig. 21.

It is understood that the two unit structures 1 can be spliced and fixed to each other by the splicing structure 103 through the modification of the splicing structure 103. Or, the splicing structure 103 is designed according to the use requirement, so that the required number of the unit structures 1 can be spliced and fixed with each other through the splicing structure 103.

Example 4:

in this embodiment, a plurality of unit structures 1 are spliced into an arrayed lattice structure. Therefore, the lattice structure can absorb large-area impact energy, reduce the plastic deformation of the lattice structure, and can be restored to the original state and reused through the action of external force after deformation.

Then, a first cover plate 2 is arranged on one side of the lattice structure, and a second cover plate 3 is arranged on the opposite side of the first cover plate 2 to form the lattice sandwich structure, so that the lattice sandwich structure can be widely applied to the fields of personnel protection, building shock absorption, impact prevention of automobiles and airplanes, protection of precise parts and the like.

As shown in FIG. 22a, a plurality of the unit structures 1 are spliced to form a fishing net lattice structure. In the fishing net-shaped lattice structure, reinforcing rods 13 are arranged at the positions of the intersecting nodes between the unit structures 1 or at the positions right below the intersecting nodes, and the reinforcing rods 13 are used for preventing two intersecting nodes connected with the reinforcing rods and the intersecting nodes right above from deforming excessively to introduce too large plastic deformation when the fishing net-shaped lattice structure deforms under stress.

In this embodiment, a reinforcing bar 13 is provided at the position of the intersection node between the unit structures 1 or at a position directly below the intersection node.

Considering that the fishing net-shaped lattice structure formed by splicing the unit structures 1 has only limited thickness, when the unit structures are used for producing and preparing the lattice sandwich structure, the same structure can be spliced along the thickness direction of the unit structures 1. Then, a first cover plate 2 is arranged on one side of the fishing net-shaped lattice structure, and a second cover plate 3 is arranged on the opposite side of the first cover plate 2, so that the lattice sandwich structure is formed.

It is understood that a plurality of the connecting rods 11 of the lattice structure can also be spliced to form a pyramid lattice structure, a Kagome lattice structure, a tetrahedral lattice structure, and the like.

Similarly, a first cover plate 2 is disposed on one side of the lattice structure such as the pyramid lattice structure, the Kagome lattice structure, or the tetrahedral lattice structure, and a second cover plate 3 is disposed on the opposite side of the first cover plate 2, so as to form a corresponding lattice sandwich structure, such as the Kagome lattice sandwich structure shown in fig. 22b and the pyramid lattice sandwich structure shown in fig. 22 c.

As shown in fig. 22a to 22c, in the three lattice sandwich structures, the unit structures 1 all use the first cover plate 2 or the second cover plate 3 as a horizontal plane when being spliced, the unit structures 1 are all in a normal placement state, an included angle between the connecting rod 11 in the unit structure 1 and the first cover plate 2 or the second cover plate 3 is theta, and theta is larger than or equal to 40 degrees and smaller than or equal to 50 degrees.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. The lattice structure-based unit structure is characterized by comprising a first base, a second base and a connecting rod for connecting the first base and the second base, wherein a reinforcing part is arranged on the periphery of the connecting rod and is arranged at a position, close to the first base or the second base, of the connecting rod;

the length of the connecting rod is L, the width of the cross section of the connecting rod along the vertical plane perpendicular to the central axis of the connecting rod is W, the thickness of the cross section of the connecting rod along the vertical plane perpendicular to the central axis of the connecting rod is T, the distance between the reinforcing part and the adjacent first base or the adjacent second base along the length direction of the connecting rod is d, T is not less than W, W/L is not less than 0.1 and not more than 0.15, and d/L is not less than 0.1 and not more than 0.3.

2. The lattice structure-based unit structure of claim 1, wherein the tie bar structure comprises one of a cylindrical structure and a prismatic structure.

3. The lattice structure-based unit structure according to claim 2, wherein the prism structure is a quadrangular prism structure.

4. The lattice structure-based unit structure of claim 1, wherein the length of the reinforcement portion along the direction in which the length of the link extends is L₁A width W of a cross section perpendicular to the vertical plane₁Wherein, L is more than or equal to 0.05₁/L≤0.15，1.1≤W₁/W≤1.2。

5. The lattice structure-based unit structure according to claim 1, wherein the number of the reinforcing parts is plural, and the plural reinforcing parts are arranged at intervals.

6. The lattice structure-based unit structure of claim 5, wherein the tie bars are provided with one of the reinforcing parts at positions close to the first base and the second base, respectively.

7. The lattice structure-based unit structure of claim 1, wherein the first base and/or the second base comprises a connecting base and a connecting portion protruding from the connecting base, and the connecting rod intersects with the connecting portion.

8. The lattice structure-based unit structure of claim 7, wherein the connecting portion includes a connecting surface for connecting the tie bars, the tie bars being perpendicular to the connecting surface.

9. The lattice structure-based unit structure of claim 7, wherein a shape of a cross section of the connection portion along the vertical plane includes one of a partial circle, a triangle, and a trapezoid.

10. The lattice structure-based unit structure according to claim 7, wherein the connecting base is provided with a splicing structure for splicing and fixing with different unit structures; and/or

11. The lattice structure-based unit structure of claim 1, wherein the unit structure is a unitary structure.

12. Lattice structure, characterized in that the lattice structure is formed by a plurality of unit structures according to any one of claims 1 to 11 being spliced together.

13. The lattice structure of claim 12, wherein a plurality of the connecting rods of the lattice structure are spliced to form at least one of a pyramid lattice structure, a Kagome lattice structure, a tetrahedral lattice structure, and a fish-net lattice structure.

14. The lattice structure of claim 13, wherein reinforcing rods are provided at positions of intersecting nodes between unit structures or at positions directly below the intersecting nodes in the fishing net-shaped lattice structure.

15. Lattice sandwich structure, characterized in that the lattice sandwich structure comprises a first cover plate, a second cover plate arranged opposite to the first cover plate, and the lattice structure according to any one of claims 12 to 14 arranged between the first cover plate and the second cover plate.