Buckling induction variable cross-section hierarchical honeycomb-like structure

Abstract

The invention provides a buckling induction variable cross-section hierarchical honeycomb-like structure, which comprises a plurality of groups of cell element structures, each cell element structure comprises a hexagonal cell element, and a plurality of levels of hexagonal cell elements are arranged in each hexagonal cell element; all the secondary hexagonal cell elements respectively extend outwards along the directions of six vertexes to form six cell ribs, and the other ends of the cell ribs are respectively connected with the vertexes of the secondary hexagonal cell elements on the adjacent outer layers and are finally connected with the hexagonal cell elements; the hexagonal cell elements with certain wall thickness, the secondary hexagonal cell elements and the cell element ribs are stretched in the axial direction and gradually transited to the section of the buckling induction layer, and then stretching continues with the section of the buckling induction layer as the symmetry plane to form a spatial hierarchical honeycomb-like structure. Geometric defects are introduced into the buckling-induced variable cross-section hierarchical honeycomb-like structure, the initial peak force of the structure is greatly reduced, and the buckling-induced variable cross-section hierarchical honeycomb-like structure has remarkable potential in the aspect of crashworthiness.

Description

Technical Field

[0001] The present invention relates to the field of honeycomb-like structures, and particularly to a buckling-induced variable cross-section hierarchical honeycomb-like structure. Background Art

[0002] With the booming development of the transportation industry, people are pursuing lighter and higher energy-absorbing materials and structures in automobiles, trains, and other transportation tools. As a common porous material, honeycomb has good mechanical properties such as light weight, high strength, excellent energy absorption, high heat insulation ability, and structural protection characteristics, and has broad application prospects in the fields of aviation, aerospace, and automobiles.

[0003] When a honeycomb structure collides, a relatively high initial peak stress will appear. Moreover, with the increase in the crushing speed, the initial peak force of the honeycomb structure in the out-of-plane direction can be increased several times. The high initial peak force and the high load rate dependence of the initial peak of the honeycomb structure under out-of-plane compressive load are not ideal for energy absorption and structural protection. Through research, it is found that the crushing performance of the honeycomb structure can be artificially controlled by changing its shape parameters. In particular, by increasing the number of layers or arranging asymmetric layers, the initial peak force of the honeycomb structure and the fluctuation of the mechanical response can be effectively reduced. Summary of the Invention

[0004] To solve the current technical problems, the main object of the present invention is to provide a buckling-induced hierarchical honeycomb-like structure for reducing the initial peak force of the structure and improving the specific energy absorption of the honeycomb structure.

[0005] To achieve the above technical features, the object of the present invention is realized as follows: A buckling-induced variable cross-section hierarchical honeycomb-like structure includes multiple cell structures, and each cell structure includes a hexagonal cell element, and a multi-level hierarchical hexagonal cell element is arranged inside the hexagonal cell element; All the secondary hexagonal cell elements respectively extend six cell ribs along six vertex directions outwards, and the other ends of the cell ribs are respectively connected to the vertices of the secondary hexagonal cell elements in the adjacent outer layer and finally connected to the hexagonal cell element; The hexagonal cell element, the secondary hexagonal cell element, and the cell rib with a certain wall thickness are stretched along the axial direction and gradually transition to the buckling-induced layer cross-section, and then continue to be stretched with the buckling-induced layer cross-section as the symmetry plane to form a spatial hierarchical honeycomb-like structure.

[0006] Preferably, the shape of the buckling-induced layer cross-section is circular or polygonal, and the size is smaller than the size of the initial hexagonal cell element.

[0007] Preferably, the hexagonal cell element is a zero-level hexagonal cell element and is a regular hexagon.

[0008] Preferably, a first-level hexagonal cell element is arranged inside the zero-level hexagonal cell element, and the size relationship is satisfied: , and the cross-sectional size of the buckling induction layer satisfies: ; In the formula: is the side length of the zero-level hexagonal cell element, is the side length of the first-level hexagonal cell element, is the size of the cross-section of the zero-level buckling induction layer, is the size of the cross-section of the first-level buckling induction layer.

[0009] Preferably, a second-level hexagonal cell element is arranged inside the first-level hexagonal cell element, and the size relationship is satisfied: , and the cross-sectional size of the buckling induction layer satisfies: ; In the formula: is the side length of the second-level hexagonal cell element, is the size of the cross-section of the second-level buckling induction layer.

[0010] Preferably, the secondary hexagonal cell element has n levels, n = 2, 3, 4..., and the side length of the hexagonal cell element at each level satisfies: , and the cross-sectional size of the buckling induction layer satisfies: ; In the formula: is n the side length of the level is n the side length of the level is n the size of the cross-section of the level is n the size of the cross-section of the level

[0011] Preferably, the wall thickness of the hierarchical honeycomb structure is equal.

[0012] Preferably, the buckling-induced variable cross-section hierarchical honeycomb structure is a variable cross-section structure with local geometric defects.

[0013] Preferably, the n size of the cross-section of the level buckling induction layer and the n side length of the level hexagonal cell element are defined as the size ratio parameter k , expressed as , and different variable cross-section structures are set according to the k value.

[0014] The present invention has the following beneficial effects: 1. The structure of the present invention can change the size parameter ratio k and the number of induced layers nThe quantity. By changing the dimensional parameter ratio k The size and the number of induced layers, different variable cross-section structures can be formed under different working conditions, and they can be flexibly applied in different engineering fields and applications.

[0015] 2. The structure of the present invention adopts a variable cross-section structure design, which can reduce the amount of material used on the premise of ensuring the structural strength, thereby reducing the self-weight of the structure. This helps to reduce the overall structural load and makes it more superior in terms of lightweight.

[0016] 3. The inside of the structure of the present invention adopts a gradient hierarchical honeycomb core. When the structural strength is insufficient, the in-plane and out-of-plane load-bearing performance of the structure can also be improved by increasing the number of layers of the core cell structure.

[0017] 4. The structure of the present invention introduces a buckling-induced layer. The buckling-induced hierarchical structure with delamination characteristics has great potential in improving crashworthiness. Under the same mass, increasing the hierarchical structure of the structure can significantly improve the energy absorption capacity of the honeycomb. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described below in conjunction with the drawings and embodiments.

[0019] Figure 1 It is a schematic perspective structure diagram of the first view of the present invention.

[0020] Figure 2 (a), (b), (c), (d) are schematic perspective structure diagrams of different shapes of buckling-induced layers of the present invention. a is a circular cross-section, b is a square cross-section, c is a hexagonal cross-section, and d is a hexagonal star cross-section.

[0021] Figure 3 It is a demonstration diagram of a hexagonal hierarchical structure.

[0022] Figure 4 It is a schematic diagram of the buckling-induced layer.

[0023] Figure 5 (a), (b) are crushing force-displacement curves of the buckling-induced variable cross-section hierarchical honeycomb structure, hexagonal honeycomb structure, and circular honeycomb structure.

[0024] Figure 6 It is a bar chart of the initial peak force of the buckling-induced variable cross-section hierarchical honeycomb structure, hexagonal honeycomb structure, and circular honeycomb structure.

[0025] In the figure: hexagonal cell element 1, first-level hexagonal cell element 2, second-level hexagonal cell 3, cell rib 4. DETAILED DESCRIPTION OF THE INVENTION

[0026] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0027] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0028] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "mounted", "connected", "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0029] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0030] Embodiment 1: See Figure 1, A buckling-induced variable cross-section hierarchical honeycomb structure, including multiple cell structures. The cell structure includes a hexagonal cell element 1, and multiple hierarchical hexagonal cell elements are provided inside the hexagonal cell element 1. All the secondary hexagonal cell elements respectively extend six cell ribs 4 outward along six vertex directions. The other ends of the cell ribs 4 are respectively connected to the vertices of the secondary hexagonal cell elements in the adjacent outer layer, and finally connected to the hexagonal cell element 1. The hexagonal cell element 1, the secondary hexagonal cell elements, and the cell ribs 4 with a certain wall thickness are stretched along the axial direction and gradually transition to the buckling-induced layer cross-section, and then continue to be stretched with the buckling-induced layer cross-section as the symmetry plane to form a spatial hierarchical honeycomb structure. By replacing the buckling-induced layer cross-section of the middle cross-section of the hierarchical honeycomb structure with other shapes and changing its size, a buckling-induced layer is obtained, forming a variable cross-section structure with a certain wall thickness, and further forming a buckling-induced variable cross-section hierarchical honeycomb structure. The buckling-induced variable cross-section hierarchical honeycomb structure introduces geometric defects, greatly reducing the initial peak force of the structure. In addition, the layered structure has significant potential in improving the crashworthiness performance by improving the specific energy absorption of the honeycomb structure.

[0031] Example 2: See Figure 2 , The shape of the buckling-induced layer cross-section is circular or polygonal, and its size is smaller than the size of the initial hexagonal cell element 1. By designing the buckling-induced layer cross-section into different size shapes as needed, the material usage can be reduced while ensuring the structural strength, thereby reducing the self-weight of the structure. This helps to reduce the overall structural load and makes it perform more excellently in terms of lightweight.

[0032] Example 3: See Figure 3 , In this example, the hexagonal cell element 1 is a zero-level hexagonal cell element and is a regular hexagon.

[0033] Example 4: In this embodiment, by providing a first-level hexagonal cell element 2 inside the zero-level hexagonal cell element and satisfying the size relationship: , and the size of the buckling-induced layer cross-section satisfies: ; In the formula: is the side length of the zero-level hexagonal cell element, is the side length of the first-level hexagonal cell element, is the size of the zero-level buckling-induced layer cross-section, is the size of the first-level buckling-induced layer cross-section.

[0034] Example 4: In this embodiment, by providing a second-level hexagonal cell 3 inside the first-level hexagonal cell element 2 and satisfying the size relationship: , and the size of the buckling-induced layer cross-section satisfies: ; where: is the side length of the secondary hexagonal cell element, is the size of the cross-section of the secondary buckling-inducing layer.

[0035] Example 5: In this example, by having n levels in the secondary hexagonal cell element, n n = 2, 3, 4..., and the side lengths of the hexagonal cell elements at each level satisfy: , and the size of the cross-section of the buckling-inducing layer satisfies: ; where: is n the side length of the nth-level hexagonal cell element, is n the side length of the (n + 1)th-level hexagonal cell element, is n the size of the cross-section of the nth-level buckling-inducing layer, is n the size of the cross-section of the (n + 1)th-level buckling-inducing layer.

[0036] Furthermore, the wall thicknesses of the hierarchical honeycomb-like structures are all equal. By adopting the same wall thickness, the processing and manufacturing process is simplified, and the processing and manufacturing difficulty is reduced.

[0037] Furthermore, the buckling-induced variable cross-section hierarchical honeycomb-like structure is a variable cross-section structure with local geometric defects.

[0038] Preferably, the ratio of the size of the cross-section of the n nth-level buckling-inducing layer to the side length of the n nth-level hexagonal cell element is defined as the size ratio parameter k , expressed as , and different variable cross-section structures are set according to the k value. By setting the value according to different force conditions, its adaptability is enhanced.

[0039] Example 6: In this example, for the buckling-induced variable cross-section hierarchical honeycomb-like structure, the middle cross-section of the hierarchical honeycomb-like structure is replaced with other shapes and its size is changed to obtain the buckling-inducing layer, forming a variable cross-section structure with a certain wall thickness, and finally obtaining the buckling-induced hierarchical honeycomb-like structure. Through the above buckling-induced variable cross-section hierarchical honeycomb-like structure, the initial peak force of the structure can be greatly reduced, and moreover, the layered structure has significant potential in improving the specific energy absorption of the honeycomb structure and thus improving the crashworthiness performance.

[0040] See Figure 5 、 Figure 6, by comparing the crashworthiness of the buckling-induced variable cross-section hierarchical honeycomb structure, hexagonal honeycomb structure, and circular honeycomb structure under the same mass, the crushing force-displacement curves of the three structures are obtained. From Figure 6 , it can be seen that the initial peaks of the circular honeycomb structure and the hexagonal honeycomb structure are higher than those of the buckling-induced variable cross-section hierarchical honeycomb structure, and the circular honeycomb structure is 33.6% higher. Compared with other honeycomb structures, this structure has better crashworthiness. This is because geometric defects are introduced into the buckling-induced variable cross-section hierarchical honeycomb structure, resulting in a decrease in its waist buckling resistance and a reduction in the initial peak force. This shows that introducing appropriate geometric defects can improve the crashworthiness of the structure.

[0041] It can be understood that the present invention is described by way of some embodiments. Those skilled in the art will know that, without departing from the spirit and scope of the present invention, various changes or equivalent substitutions can be made to these features and embodiments. Additionally, under the teaching of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application belong to the scope protected by the present invention.

Claims

1. A buckling-induced variable cross-section hierarchical honeycomb structure, characterized in that It includes multiple groups of cell structures, and the cell structure includes a hexagonal cell element (1), and multiple levels of secondary hexagonal cell elements are arranged inside the hexagonal cell element (1); All the secondary hexagonal cell elements respectively extend six cell ribs (4) outward along six vertex directions, and the other ends of the cell ribs (4) are respectively connected to the vertices of the secondary hexagonal cell elements in the adjacent outer layer and finally connected to the hexagonal cell element (1); The hexagonal cell element (1), the secondary hexagonal cell elements and the cell ribs (4) with a certain wall thickness are stretched along the axial direction and gradually transition to the cross-section of the buckling induction layer, and then continue to be stretched with the cross-section of the buckling induction layer as the symmetry plane to form a spatial hierarchical honeycomb-like structure.

2. The flexure-induced variable cross-section hierarchical honeycomb structure according to claim 1, characterized in that: The shape of the cross-section of the buckling induction layer is circular or polygonal, and the size is smaller than the size of the initial hexagonal cell element (1).

3. The flexure-induced variable cross-section hierarchical honeycomb structure according to claim 1, wherein: The hexagonal cell element (1) is a zero-level hexagonal cell element and is a regular hexagon.

4. The flexure-induced variable cross-section hierarchical honeycomb structure according to claim 3, wherein: A first-level hexagonal cell element (2) is provided inside the zero-level hexagonal cell element, and the dimensional relationship is satisfied: , and the cross-sectional dimension of the buckling induction layer satisfies: ; where: is the side length of the zero-level hexagonal cell element, is the side length of the first-level hexagonal cell element, is the dimension of the cross-section of the zero-level buckling induction layer, is the dimension of the cross-section of the first-level buckling induction layer.

5. The flexure-induced variable cross-section hierarchical honeycomb structure according to claim 4, wherein: The first-level hexagonal cell element (2) is internally provided with a second-level hexagonal cell (3), and the following dimensional relationship is satisfied: , and the cross-sectional dimension of the buckling-inducing layer satisfies: ; where: is the side length of the second-level hexagonal cell element, is the dimension of the cross-section of the second-level buckling-inducing layer.

6. The flexure-induced variable cross-section hierarchical honeycomb structure according to claim 5, wherein: The secondary hexagonal cell element has n levels, n = 2, 3, 4..., and the side length of the hexagonal cells at each level satisfies: , and the cross-sectional size of the buckling-induced layer satisfies: ; where: is n the side length of the -th n level hexagonal cell element, is n the side length of the +1-th n level hexagonal cell element, the cross-sectional size of the -th n +1-th buckling-induced layer cross-section.

7. The flexure-induced variable cross-section hierarchical honeycomb structure according to claim 6, wherein: The wall thicknesses of the hierarchical honeycomb-like structure are all equal.

8. The flexure-induced variable cross-section hierarchical honeycomb structure according to claim 1, characterized in that: The buckling induction variable cross-section hierarchical honeycomb-like structure is a variable cross-section structure with local geometric defects.

9. The buckling-induced variable cross-section hierarchical honeycomb structure according to claim 6, wherein: The n size of the cross-section of the buckling-induced layer at the n level and the side length of the hexagonal cell element at the k level are defined as the size ratio parameter , denoted as k , and different variable cross-section structures are set according to the value.

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