Egg-box type cell with gradient layering features and egg-box type structure

Abstract

The application relates to the field of mechanical metamaterial structure design, in particular to an egg-box type cell with gradient stacking characteristics, which comprises an upper cell and a lower cell; the upper cell and the lower cell are arranged in a mirror-symmetrical mode; the upper cell and the lower cell are the same in structure and each comprises at least four layers of cell units which are the same in periodic spacing, different in forming height, the same or different in cell unit matrix thickness and arranged in a certain mode to form a gradient layer. The application has the beneficial effects that: due to the above technical scheme, the egg-box type cell of the application forms the gradient change of the mechanical characteristics along the thickness direction through the symmetrical superposition of the cell units, has the structural gradient change characteristics and the out-of-plane negative Poisson's ratio characteristics, and improves the equivalent stiffness, compression characteristics, energy absorption characteristics, vibration characteristics and other mechanical properties.

Description

Technical Field

[0001] This invention relates to the field of mechanical metamaterial structure design, specifically an egg-box type unit cell and egg-box type structure with gradient stacking characteristics. Background Technology

[0002] Lightweight structures are high-performance material structures with extremely high porosity, achieving overall structural and functional requirements through the rational design of in-plane periodic unit cells. From a mechanical perspective, lightweight structural materials possess high specific strength, high specific surface area, negative Poisson's ratio, and excellent buffering and energy absorption properties. These superior comprehensive mechanical properties enable their widespread application in the manufacture of lightweight, impact- and damage-resistant, vibration-damage-reducing, noise-reducing, and heat and mass transfer structures for high-end technical equipment. Egg-box structures are a simple and versatile lightweight structure that can be efficiently manufactured by stamping and rolling ordinary metal sheets. However, currently, they are often used with individual egg-box structural panels, which fails to fully utilize their comprehensive mechanical properties. In fact, egg-box structures can easily be produced with various geometric states by adjusting manufacturing process parameters. These panels, through rationally designed layering and combination, can achieve a structural form with a gradient distribution of mechanical states in the thickness direction and out-of-plane negative Poisson's ratio characteristics, thus meeting the requirements of various lightweight structures in different application scenarios. Summary of the Invention

[0003] This invention discloses an egg-box type unit cell and egg-box type structure with gradient stacking features to solve any of the above-mentioned technical problems and other potential problems in the prior art.

[0004] To solve the above-mentioned technical problems, the technical solution of the present invention is: an egg-box type unit cell with gradient stacking features, wherein the egg-box type unit cell includes an upper unit cell and a lower unit cell; the upper unit cell and the lower unit cell are arranged in a mirror symmetric manner;

[0005] Furthermore, the upper and lower unit cells have the same structure, each including at least 4 layers of a type of unit cell. The unit cells have the same periodic spacing, the same thickness of the unit cell matrix, and different forming heights. Moreover, the multiple layers of the type of unit cell form a gradient layer through a certain connection method.

[0006] The unit cells have the same periodic spacing, different unit cell matrix thicknesses, and different forming heights.

[0007] The unit cell is projected onto a two-dimensional plane containing the first direction (along the X-axis) and the second direction (along the y-axis) in the shape of a square. The square has a peak at the center of symmetry and a trough at the center of each of the four sides. The peaks and troughs are connected by curved surfaces.

[0008] Furthermore, the connection method is as follows: for odd-numbered layers, the connection between the nth layer and the (n+1)th layer is a superposition connection of the lowest points of the unit cells, where n = 1, 3, 5, 7, ...

[0009] Even-numbered layers are formed by superimposing and connecting the highest points of unit cells between the m-th and m+1-th layers, where m = 2, 4, 6, 8...i.

[0010] Furthermore, the forming height of the nth layer unit cell is less than the forming height of the (n+1)th layer unit cell; the forming height of the mth layer unit cell is greater than the forming height of the (m+1)th layer unit cell.

[0011] An egg-box structure with gradient stacking features, wherein the egg-box structure is composed of the aforementioned egg-box unit cells arranged in a planar lattice.

[0012] The periodic spacing of each of the egg-box-shaped units is the same.

[0013] A gradient egg carton-shaped plate, the gradient egg carton-shaped plate having the above-described egg carton-shaped structure.

[0014] To better leverage the advantages of egg-box structures—lightweight, impact-resistant, and energy-absorbing vibration-damping—and to adjust their mechanical properties, such as equivalent stiffness, through various means, this invention designs a stacked egg-box unit cell with structural gradient variation characteristics and out-of-plane negative Poisson bit properties. This egg-box unit cell can, on the one hand, form a structure with mechanical properties that change gradient along the thickness direction by stacking unit cells with the same periodic spacing but different thicknesses and forming heights; on the other hand, it can adjust the mechanical properties of the egg-box unit cell, such as equivalent stiffness, compressive characteristics, energy absorption characteristics, and vibration characteristics, by changing the magnitude and distribution of the gradient difference.

[0015] This invention designs an egg-box-shaped unit cell with gradient stacking characteristics. The overall structural feature of the egg-box-shaped unit cell is a periodically arranged, double-arrow-shaped stacked egg-box plate with symmetry along a curved neutral layer, forming a negative Poisson's ratio structure with a substrate thickness gradient or forming height gradient, resembling a "double-arrow" shape in the plate thickness direction. The specific stacking steps are described below, using a single unit cell as an example:

[0016] Step 1: Starting from the neutral layer of the board and working outwards (the layer closest to the neutral layer is the 1st layer, the layer closest to the 1st layer but farther from the neutral layer is the 2nd layer, and so on), the troughs (the lowest points of the single board) between the nth and n+1th layers are superimposed and connected (n=1,3,5,7···).

[0017] Step 2: Starting from the neutral layer of the board and working outwards (the layer closest to the first layer, and the layer one layer away from the neutral layer is considered the second layer), the peaks (the highest points of the single board) between the m-th and m+1-th layers are superimposed and connected. (m=2,4,6,8···).

[0018] Step 3: The structure formed by superimposing Step 1 and Step 2 is symmetrically copied and superimposed with the bottom plane of the lowest layer as the reference, resulting in a double arrow structure symmetrical in the thickness direction.

[0019] Restrictions: From the neutral layer of the sheet outwards (the layer closest to the neutral layer is the 1st layer, the layer closest to the 1st layer but farther from the neutral layer is the 2nd layer, and so on), the forming height of the nth layer unit cell must not be higher than the forming height of the (n+1)th layer; the forming height of the mth layer unit cell must not be lower than the forming height of the (m+1)th layer.

[0020] In the above structure, the periodic spacing refers to the dimension along the length of the unit cell model, the forming height refers to the vertical distance from the highest peak to the lowest trough of the unit cell, and the thickness refers to the substrate thickness of the egg-shaped unit cell.

[0021] In the above structure, the number of stacked unit cell layers can be selected according to the gradient requirements, such as 4, 6, 8, or 10. However, it should be noted that to ensure a symmetrical structure, the number of layers must be even.

[0022] The key advantages of this invention are: by employing the above-mentioned technical solution, the structure of this invention can achieve a negative Poisson's ratio along the thickness direction of the outer edge of the sheet material. Furthermore, the gradient mechanical properties of the structural material, such as equivalent stiffness, negative Poisson's ratio, and vibration energy absorption characteristics, can be easily adjusted by regulating the stacking and combination of the single sheets. Simultaneously, the geometry of the single sheets can be flexibly adjusted according to design requirements. For example, the shape of the egg-box can be changed by adjusting the sine cluster function, and the shape of the egg-box-shaped single sheet can be changed by adjusting the periodic spacing, thickness, or forming height. It offers high design freedom and is convenient and stable in molding and manufacturing. Attached Figure Description

[0023] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0024] Figure 1 This is a schematic diagram of an egg-box type unit cell with gradient stacking features according to the present invention.

[0025] Figure 2 This is a schematic diagram of the structure of the unit cell of the present invention.

[0026] Figure 3 This is a structural schematic diagram of the cross-sectional side view of the unit cell of the present invention.

[0027] Figure 4 This is a schematic diagram of the stacking method of multilayer thickness gradient egg box unit cells of the present invention (taking 8 layers as an example).

[0028] Figure 5 This is a schematic diagram of an egg-box-shaped structure with gradient stacking features.

[0029] In the picture:

[0030] 1. Egg-box type unit cell, I. Upper unit cell, II. Upper unit cell, 2. Unit cell, 3. Periodic spacing of unit cell, 4. Formation height of unit cell, 5. Thickness of unit cell, 6. Unit cell with a thickness of 0.5 mm and a formation height of 4 mm, 7. Unit cell with a thickness of 0.5 mm and a formation height of 8 mm, 8. Unit cell with a thickness of 0.3 mm and a formation height of 4 mm, 9. Unit cell with a thickness of 0.3 mm and a formation height of 8 mm, 10, 11, 12. Figure 3 The three connection points of the unit cell are: 13. Unit cell with a thickness of 0.5 mm and a forming height of 2 mm; 14. Unit cell with a thickness of 0.5 mm and a forming height of 6 mm; 15. Unit cell with a thickness of 0.5 mm and a forming height of 4 mm; and 16. Unit cell with a thickness of 0.5 mm and a forming height of 8 mm. Detailed Implementation

[0031] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0032] like Figure 1 As shown, the present invention discloses an egg-box type unit cell with gradient stacking features, characterized in that the egg-box type unit cell includes an upper unit cell and a lower unit cell; the upper unit cell and the lower unit cell are arranged in a mirror symmetric manner;

[0033] Furthermore, the upper and lower unit cells have the same structure, each including at least 4 layers of a type of unit cell. The unit cells have the same periodic spacing, the same thickness of the unit cell matrix, and different forming heights. Moreover, the multiple layers of the type of unit cell form a gradient layer through a certain connection method.

[0034] The connection method is as follows: for odd-numbered layers, the connection between the nth layer and the (n+1th)th layer is the superposition and connection of the lowest points of the unit cells, where n = 1, 3, 5, 7...i;

[0035] Even-numbered layers are formed by superimposing and connecting the highest points of unit cells between the m-th and m+1-th layers, where m = 2, 4, 6, 8...i.

[0036] The forming height of the nth layer unit cell is less than the forming height of the (n+1)th layer unit cell; the forming height of the mth layer unit cell is greater than the forming height of the (m+1)th layer unit cell.

[0037] The unit cells have the same periodic spacing, different unit cell matrix thicknesses, and different forming heights.

[0038] like Figure 2 and Figure 3 As shown, the unit cell is projected onto the two-dimensional plane containing the first and second directions as a square, with a peak at the center of symmetry and a trough at the center of each of the four sides, and the peaks and troughs are connected by curved surfaces.

[0039] An egg-box structure with gradient stacking features, wherein the egg-box structure is composed of the aforementioned egg-box unit cells arranged in a planar lattice.

[0040] The periodic spacing of each egg-box-shaped unit cell in the egg-box structure is the same.

[0041] A gradient egg carton-shaped plate, wherein the gradient egg carton-shaped plate has the above-mentioned egg carton-shaped structure.

[0042] Example:

[0043] One appearance of the egg carton structure is as follows Figure 5 As shown, an egg-box structure can be obtained by arranging the egg-box type unit cell 1. Its side surface shape is a sine function. The figure shows a 10×10 veneer. It should be noted that depending on the required veneer size, it does not necessarily have to be a complete unit cell; for example, an 11.3×12.6 veneer is also possible. See the dimensioning of the egg-box type unit cell for details. Figure 3 The structure is controlled by three dimensions: periodic spacing 3, forming height 4, and thickness 5. The following examples, using two multi-layered gradient egg-shaped unit cells, illustrate the specific structure.

[0044] Example 1:

[0045] The design of an 8-layer double-arrow thickness gradient egg-shaped structure with a period spacing of 30mm, a forming height of 8 / 4mm, and a thickness of 0.5 / 0.3mm is as follows:

[0046] First, according to the above dimensions, two of each of the following four types of single-layer egg-box shaped unit cells were fabricated: 6 (periodic spacing of 30mm, forming height of 4mm, thickness of 0.5mm), 7 (periodic spacing of 30mm, forming height of 8mm, thickness of 0.5mm), 8 (periodic spacing of 30mm, forming height of 4mm, thickness of 0.3mm), and 9 (periodic spacing of 30mm, forming height of 8mm, thickness of 0.3mm). Then, according to... Figure 1As shown, eight layers of unit cells are stacked, with unit cell 6 being the first layer (closest to the neutral layer), unit cell 7 being the second layer (adjacent to the first layer, slightly farther from the neutral layer), unit cell 8 being the third layer (adjacent to the second layer), and unit cell 9 being the fourth layer (adjacent to the third layer, farthest from the neutral layer). Connection point 10 connects the trough of unit cell 6 in the first layer with the trough of unit cell 7 in the second layer; connection point 11 connects the peak of unit cell 7 in the second layer with the peak of unit cell 8 in the third layer; and connection point 12 connects the trough of unit cell 8 in the third layer with the trough of unit cell 9 in the fourth layer. Note that the structure is mirror-symmetric along the central plane.

[0047] Example 2:

[0048] The design of an 8-layer double-arrow-shaped egg-shaped structure with a period spacing of 30mm, forming heights of 8 / 4mm and 6 / 2mm, and a thickness of 0.5mm is as follows:

[0049] First, according to the above dimensions, two of each of the following four types of single-layer egg-box shaped unit cells were fabricated: 13 (periodic spacing of 30mm, forming height of 2mm, thickness of 0.5mm), 14 (periodic spacing of 30mm, forming height of 6mm, thickness of 0.5mm), 15 (periodic spacing of 30mm, forming height of 4mm, thickness of 0.5mm), and 16 (periodic spacing of 30mm, forming height of 8mm, thickness of 0.5mm). Then, according to... Figure 4 The layers are stacked as shown. Unit cell 13 is the first layer (the layer closest to the neutral layer), unit cell 14 is the second layer, unit cell 15 is the third layer, and unit cell 16 is the fourth layer. The connection method at the stacking joints is the same as in Example 1. It is particularly important to note that the height difference between any two layers (e.g., the first layer unit cell 13 and the second layer unit cell 14, the third layer unit cell 15 and the fourth layer unit cell 16) must be consistent to eliminate the influence of the overall height of the multi-layer unit cell model. Finally, this structure is arrayed 10 times in the length and width directions to obtain an 8-layer egg-shaped structural plate with a negative Poisson bit property and a shaped height gradient, as shown. Figure 5 As shown.

[0050] The above description is merely a specific embodiment of the present invention and should not be construed as limiting the scope of the invention. Therefore, the unit cell design in the egg carton structure of the present invention, including the shape, material, and size of the egg carton unit cell; the gradient design, including the gradient type (thickness, forming height, etc.), gradient difference, gradient distribution (increasing or decreasing from the inside to the outside, or other gradient distribution patterns); changes in the stacking method and the number of stacked layers; the unit cell array method; and equivalent variations and modifications to the structure should all still fall within the scope of this patent.

[0051] In summary, the multi-layered egg-box structure with negative Poisson bit characteristics designed in this invention is unprecedented. In particular, the free stacking and arrangement of multiple layers of unit cells with different gradients is extremely flexible and adaptable to a considerable number of practical applications. By adjusting the thickness gradient, forming height gradient, gradient difference, and gradient distribution, the mechanical properties of this structure, such as equivalent stiffness, energy absorption and vibration reduction performance, and compressive performance, can be flexibly adjusted, demonstrating its progressiveness and universality.

[0052] The foregoing has provided a detailed description of an egg-box type unit cell and egg-box type structure with gradient stacking features provided in the embodiments of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​this application; at the same time, for those skilled in the art, there will be changes in specific implementation methods and application scope based on the idea of ​​this application. Therefore, the content of this specification should not be construed as a limitation of this application.

[0053] Certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that hardware manufacturers may use different names to refer to the same component. This specification and claims do not distinguish components based on differences in name, but rather on differences in function. The terms "comprising" and "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising / including but not limited to". "Approximately" means that within an acceptable margin of error, those skilled in the art can solve the technical problem and substantially achieve the technical effect within a certain margin of error. The following descriptions in the specification are preferred embodiments for carrying out this application; however, these descriptions are for the purpose of illustrating the general principles of this application and are not intended to limit the scope of this application. The scope of protection of this application shall be determined by the appended claims.

[0054] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a product or system comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a product or system. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the product or system that includes said element.

[0055] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0056] The foregoing description illustrates and describes several preferred embodiments of this application. However, as previously stated, it should be understood that this application is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the application concept described herein through the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of this application should be within the protection scope of the appended claims.

Claims

1. An egg-box type cell having a gradient layering feature, characterised in that, The egg-box type unit cell comprises an upper unit cell and a lower unit cell; the upper unit cell and the lower unit cell are arranged in a mirror-symmetrical manner; and the upper unit cell and the lower unit cell are identical in structure and each comprises at least four layers of a type of unit cell, the unit cells are identical in periodic interval and unit cell base thickness but different in forming height, and the multiple layers of the type of unit cell are connected in a certain connection manner to form a gradient layer; The unit cells are identical in periodic interval but different in unit cell base thickness and forming height. The unit cell is projected on a two-dimensional plane in a first direction and a second direction as a square, and the square has a wave peak at a center of symmetry and a wave valley at a center of each side line, and the wave peak and the wave valley are connected by a curved surface; The connection manner is that: for odd layers, the lowest point of a unit cell in the nth layer is connected to the lowest point of a unit cell in the (n+1)th layer, and n=1, 3, 5, 7, …; and for even layers, the highest point of a unit cell in the mth layer is connected to the highest point of a unit cell in the (m+1)th layer, and m=2, 4, 6, 8, …; The forming height of the unit cell in the nth layer is smaller than the forming height of the unit cell in the (n+1)th layer; and the forming height of the unit cell in the mth layer is greater than the forming height of the unit cell in the (m+1)th layer.

2. An egg box type structure having a gradient layering feature, characterized by, The egg-box type structure is arranged in a planar point array manner by the egg-box type unit cell of claim 1.

3. The egg carton structure of claim 2, wherein, The periodic interval of each egg-box type unit cell of the egg-box type structure is identical.

4. A gradient egg box type plate characterized by, The gradient egg-box type plate has the egg-box type structure of claim 3.

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