Multilayer honeycomb-like composite energy absorption structure and preparation method thereof

Abstract

The invention belongs to the field of light structure products and application thereof, and discloses a preparation method of a multi-layer honeycomb-like composite energy absorption structure, which comprises the following steps: cutting and bending sheets to be pasted to form a foldable sandwich structure, and cutting a plurality of first sheets and second sheets with the same size and thickness; the front face of the first sheet is coated with an adhesive at intervals to form first front face adhesive tapes with the preset width, and first front face block-to-be-attached areas are formed between the adjacent first front face adhesive tapes; the back face of the first sheet is coated with adhesives at intervals, and each first back face adhesive tape is aligned with the center position of the first front face block-to-be-attached area; the front face and the back face of the second sheet are coated with adhesive tapes, each second back face adhesive tape is aligned with the first front face adhesive tape of the first sheet on the upper layer, and each second front face adhesive tape is aligned with the first back face adhesive tape of the first sheet on the upper layer; and a sandwich structure is bonded between each or part of the first sheet and the second sheet, the first sheet and the last sheet are stretched, and the multi-layer honeycomb-like composite energy absorption structure is obtained.

Description

Technical Field

[0001] The present invention belongs to the field of lightweight structural products and their applications, and in particular relates to a multi-layer honeycomb-like composite energy-absorbing structure and a preparation method thereof. Background Art

[0002] At present, in addition to ensuring the safety of passengers, high-speed trains, cars, ships, airplanes and other means of transportation should gradually meet the increasingly urgent demand for lightweight, and lightweight structures have been widely used in the field of transportation. Vertex hierarchical structures are favored for their excellent mechanical properties in terms of load-bearing and impact. The existing more traditional hexagonal honeycomb energy-absorbing structures have many shortcomings in terms of load-bearing capacity, crash resistance, sound insulation and thermal insulation. More and more studies have found that honeycomb-like structures with hierarchical design and hybrid design can significantly improve the honeycomb's load-bearing capacity, specific energy absorption and sound absorption and vibration isolation performance. However, due to the complex structure, this type of honeycomb generally requires wire cutting, mold layer-by-layer gluing or 3D printing process forming, which is difficult to process through more traditional methods. The high cost of processing and manufacturing greatly limits the engineering application of this type of honeycomb. A honeycomb-like structure forming method with lower cost, higher load-bearing capacity and better crash resistance is urgently needed.

[0003] In the prior art, patent application number 201420135084.5 discloses an aluminum honeycomb energy absorbing block, which includes an upper panel, a lower panel and an aluminum honeycomb core, wherein the aluminum honeycomb core is arranged between the upper panel and the lower panel, and the aluminum honeycomb core is arranged in a rectangular shape, and edges are arranged on the periphery of the six sides of the aluminum honeycomb core. The aluminum honeycomb core includes a plurality of hexagonal platinum sheet cores, and the plurality of hexagonal platinum sheet cores are adhered together by an adhesive, the side length of the hexagonal platinum sheet core is greater than 2 mm, the thickness of the hexagonal platinum sheet core is 0.08 mm, the height of the aluminum honeycomb core is greater than 60 mm, and a mounting hole is arranged inside the aluminum honeycomb core, and a filler is arranged inside the mounting hole.

[0004] Patent application number 201610539128.4 discloses a honeycomb structure and design method for improving structural strength. The honeycomb structure of the present invention is composed of a periodically folded honeycomb cell array. The periodic folding can improve the structural strength of the honeycomb structure in the coplanar direction. When the honeycomb structure is used as a buffer energy absorption structure, its energy absorption capacity can be improved. At the same time, the honeycomb structure has an approximately isotropic characteristic. The honeycomb cells of each folding cycle are folded twice. The first folding direction is arbitrary, and the second folding direction is opposite to the first folding direction. The angle between the surface of the honeycomb cell after folding and the surface of the honeycomb cell before folding is in the range of 10° to 34°. The periodically folded honeycomb cells are connected in series along non-planar directions and arrayed in the coplanar direction after connection, which can effectively improve the structural strength of the honeycomb structure in the coplanar direction. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the above background art, and to provide a multi-layer honeycomb-like composite energy-absorbing structure and a preparation method thereof that can improve the load-bearing capacity and crashworthiness, and have a low cost and simple and controllable operation in the preparation process. To solve the above technical problems, the technical solution proposed by the present invention is as follows: A preparation method for a multi-layer honeycomb-like composite energy-absorbing structure, comprising: Cut and bend the sheet to be pasted to form a foldable core structure. The core structure has a top surface and a bottom surface of the same length, with folding sides in the middle. After the sides are folded, they fit with the top surface and the bottom surface, and a polygonal structure is formed after the sides are stretched. Cut a plurality of sheets of the same size and thickness; the sheets include a first sheet and a second sheet. Apply an adhesive at equal intervals on the front surface of the first sheet to form a first front adhesive tape with a predetermined width, and form a first front block area to be pasted between adjacent first front adhesive tapes. Apply an adhesive at equal intervals on the back surface of the first sheet to form a first back adhesive tape with a predetermined width, and form a first back block area to be pasted between adjacent first back adhesive tapes. Each first back adhesive tape is aligned with the center position of the first front block area. Apply an adhesive at equal intervals on the front surface of the second sheet to form a second front adhesive tape with a predetermined width, and form a second front block area to be pasted between adjacent second front adhesive tapes. Apply an adhesive at equal intervals on the back surface of the second sheet to form a second back adhesive tape with a predetermined width, and form a second back block area to be pasted between adjacent second back adhesive tapes. Each second back adhesive tape is aligned with the first front adhesive tape of the upper layer, and each second front adhesive tape is aligned with the first back adhesive tape of the upper layer. Prepare a plurality of first sheets and second sheets, bond the core structure between each or some of the first sheets and the second sheets, and the top surface and the bottom surface of the core structure are aligned with the adhesive tapes of the first sheet and the second sheet. Apply a reverse tensile force at the center positions of the block areas to be pasted on the first sheet and the last sheet, and stretch open the folding sides of the core structure to obtain a multi-layer honeycomb-like composite energy-absorbing structure.

[0006] In one embodiment, the connection ports of the foldable core structure formed by cutting and bending the sheet are located on the top surface and the bottom surface. When the core structure is bonded between the first sheet and the second sheet, the connection ports are bonded through the adhesive tape.

[0007] In one embodiment, the lengths of the top surface and the bottom surface of the core structure are the same as the width of the adhesive tape, and the width of the block area to be pasted on the first sheet and the second sheet is n times the width of the adhesive tape, where n≥3.

[0008] In one embodiment, the side of the sandwich structure is formed by multiple folds, forming a serrated polygon structure under incomplete stretching conditions; the folding form can be inner folding, outer folding or combined folding.

[0009] In one embodiment, by adjusting the folding method and quantity of the sandwich structure between the first sheet and the second sheet, the length of the adhesive tape and the side length of the sandwich structure are changed, and a honeycomb-like structure with various shape combinations is obtained.

[0010] In one embodiment, multiple groups of stretching jigs with the same width as the adhesive tape are arranged at the center positions of the areas to be pasted of the first sheet and the last sheet. The axial stretching movement and the lateral movement of each jig cooperate with each other to complete the stretching of the folded side of the sandwich structure and the bending forming of the sheet, and a multi-layer honeycomb-like composite energy-absorbing structure is obtained.

[0011] Based on the same inventive concept, a multi-layer honeycomb-like composite energy-absorbing structure obtained by the preparation method as described above is also provided.

[0012] In one embodiment, the multi-layer honeycomb-like composite energy-absorbing structure is composed of octagons and quadrilaterals. Adjacent octagons are connected by quadrilaterals, and the sides of the quadrilaterals at the connection are co-edged with the sides of the octagons.

[0013] In one embodiment, the multi-layer honeycomb-like composite energy-absorbing structure is composed of octagons, quadrilaterals and hexagons. One group of opposite sides of the quadrilateral connects adjacent hexagons, and the other group of opposite sides connects adjacent octagons.

[0014] In one embodiment, the thickness of the sheet is 0.01 mm to 0.3 mm, and the sheet is a metal foil or a thin paper sheet.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: The multi-layer honeycomb-like composite energy-absorbing structure obtained by the preparation method of the multi-layer honeycomb-like composite energy-absorbing structure of the present application, compared with the existing traditional honeycomb structure mainly composed of hexagons, the multi-layer honeycomb-like composite energy-absorbing structure obtained by the above method of the present application uses octagons as the main honeycomb cells of the honeycomb, and by introducing small cells (quadrilaterals or hexagons) in the node areas where the honeycomb cell walls intersect, local stress concentration during loading is reduced, and the occurrence area of the equivalent plastic strain of the structure during impact or compression is expanded, greatly improving the structural deformation mode. Compared with the traditional honeycomb structure of the same mass, due to the introduction of local improvement features in this structure, the specific energy absorption during out-of-plane compression is greatly improved, which can be increased by more than 50%. Further, the above staggered pasting is used to form the basic sheet unit, and the sheet to be pasted is cut and bent to form a foldable sandwich structure. The sandwich structure is first folded to form corresponding pasting edges and non-pasting edges, and after all pasting, various honeycomb shapes (such as octagons, hexagons, quadrilaterals) combined are obtained after stretching and unfolding. The operation is simple and controllable, and the manufacturing cost is greatly reduced compared with the previous hierarchical and polygonal hybrid honeycomb structure forming schemes. At the same time, according to specific needs, the sandwich structure is pasted between some of the first sheet and the second sheet, and the sandwich structure is not provided between some of the first sheet and the second sheet. By adjusting the length of the pasting band and the side length of the sandwich structure, honeycomb-like structures with various specially customized shape combinations can be obtained. Description of the Drawings

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0017] Figure 1 Schematic diagram of the front structure of the first sheet of the multi-layer honeycomb-like composite energy-absorbing structure in one embodiment; Figure 2 Schematic diagram of the back structure of the first sheet of the multi-layer honeycomb-like composite energy-absorbing structure in one embodiment; Figure 3 Schematic diagram of the sandwich structure of the multi-layer honeycomb-like composite energy-absorbing structure in one embodiment; Figure 4 Schematic diagram of the structure of the multi-layer honeycomb-like composite energy-absorbing structure before stretching (showing dimensions) in one embodiment; Figure 5 Schematic diagram of the structure of the multi-layer honeycomb-like composite energy-absorbing structure before stretching (not showing dimensions) in one embodiment; Figure 6Schematic diagram of the honeycomb structure after stretch forming of a multi-layer honeycomb-like composite energy absorption structure in one embodiment; Figure 7 Schematic diagram of the structure before stretching of a multi-layer honeycomb-like composite energy absorption structure in one embodiment, ignoring the thickness of the adhesive tape; Figure 8 Schematic diagram of the structure after honeycomb stretch forming (without showing the adhesive tape) of a multi-layer honeycomb-like composite energy absorption structure in one embodiment; Figure 9 Schematic diagram of the cell stretch forming process of a multi-layer honeycomb-like composite energy absorption structure in one embodiment; Figure 10 Schematic diagram of the structure after stretching of a multi-layer honeycomb-like composite energy absorption structure in another embodiment; Figure 11 Schematic diagram of the structure after stretching of a multi-layer honeycomb-like composite energy absorption structure in another embodiment. Specific embodiments

[0018] For the convenience of understanding the present invention, the following will describe the present invention more comprehensively and meticulously in conjunction with the accompanying drawings of the specification and preferred embodiments, but the protection scope of the present invention is not limited to the following specific embodiments.

[0019] Unless otherwise defined, all professional terms used hereinafter have the same meaning as commonly understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the protection scope of the present invention.

[0020] Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment, etc. used in the present invention can be obtained through the market or can be prepared by existing methods.

[0021] Please refer to Figures 1-11 , a preparation method of a multi-layer honeycomb-like composite energy absorption structure, comprising: S1. Cut and bend the sheet to be pasted to form a foldable sandwich structure. The sandwich structure has a top surface and a bottom surface with the same length, and symmetric folding sides in the middle. After the sides are folded, the top surface and the bottom surface are attached, and a polygonal structure, generally a quadrilateral, is formed after the sides are stretched.

[0022] Specifically, as shown in a of Figure 3 , the top surface and the bottom surface are arranged in parallel, the lengths of the top surface and the bottom surface are both L3, and the lengths of the top surface and the bottom surface are the same. As shown in Figure 3As shown in b, the overall length of the sandwich structure is W. The sandwich structure is a three-dimensional structure with a quadrilateral cross-section, which becomes flat after being folded and flattened. The side edges between the bottom and top surfaces are folding side edges. The side edges of the sandwich structure are formed by multiple folds and form a serrated polygon structure under incomplete stretching conditions. The folding form can be inner folding, outer folding, or combined folding. The folding method can be, for example, Figure 3 the concave folding shown in a. In other embodiments, the folding method can also be to form creases by convexity. Preferably, there is only one crease for each side edge, and it is located on the central axis of the folding side edge, with symmetric folding. In this way, the number of folds is the least and the most convenient and fast. In a specific embodiment, there can also be multiple creases on the folding side edge.

[0023] It should be noted that the S1 step can be completed before the treatment of the first sheet and the second sheet, or after the treatment of the first sheet and the second sheet. Considering the setting time of the adhesive, preferably, the S1 step can be completed first.

[0024] S2. Cut multiple sheets with the same size and thickness; the sheets include a first sheet and a second sheet.

[0025] To form a multi-layer honeycomb structure, according to the required number of layers, the corresponding number of sheets can be cut. The first sheet and the second sheet are the same in material, shape, and size, and the only difference is the position where the adhesive is coated.

[0026] Specifically, the thickness of the sheet is 0.01 mm to 0.3 mm, and the sheet can be a metal foil or a thin paper sheet. The sheet is cut into multiple rectangles with equal length and width, where the length of the rectangle is , and the width of the rectangle is . Where the direction is the thickness of the honeycomb after the honeycomb-like stretching and forming. Therefore, the overall length of the sandwich structure is W, which is consistent with the first sheet and the second sheet.

[0027] S3. Coat the adhesive at intervals on the front surface of the first sheet to form a first front adhesive tape with a predetermined width, and form a first front waiting-to-be-pasted block area between adjacent first front adhesive tapes.

[0028] Specifically, please refer to Figure 1 . In an embodiment, the width of the first front adhesive tape is L1, and a first front waiting-to-be-pasted block area is formed between adjacent first front adhesive tapes, and its width is L2. The width of L2 is greater than the width of L1, which is to have space for corresponding when forming the adhesive tape on the back surface.

[0029] S4. Apply the adhesive at intervals on the back surface of the first sheet to form the first back adhesive tape with a predetermined width. Form the first back area to be pasted between adjacent first back adhesive tapes. Each first back adhesive tape is aligned with the center position of the first front area to be pasted.

[0030] Specifically, please refer to Figure 2 , in an embodiment, the width of the first back adhesive tape is L1, and the first front area to be pasted is formed between adjacent first front adhesive tapes, and its width is L2. The width of L2 is greater than the width of L1, which is for having space for correspondence when facing the second sheet.

[0031] S5. Apply the adhesive at intervals on the front surface of the second sheet to form the second front adhesive tape with a predetermined width. Form the second front area to be pasted between adjacent second front adhesive tapes.

[0032] S6. Apply the adhesive at intervals on the back surface of the second sheet to form the second back adhesive tape with a predetermined width. Form the second back area to be pasted between adjacent second back adhesive tapes. Each second back adhesive tape is aligned with the first front adhesive tape of the first sheet in the upper layer, and each second front adhesive tape is aligned with the first back adhesive tape of the first sheet in the upper layer.

[0033] The formation process of the second sheet and the first sheet is the same. The widths of the obtained second front adhesive tape and second back adhesive tape are also L1, and the widths of the second front area to be pasted and the second back area to be pasted are also L2.

[0034] S7. Prepare multiple first sheets and second sheets. Bond the sandwich structures between each or part of the first sheets and second sheets, and the top surface and bottom surface of the sandwich structure are aligned with the adhesive tapes of the first sheet and the second sheet; In an embodiment, after the first sheet is made, the top surfaces of multiple sandwich structures can be bonded to the adhesive tape on the front surface or the back surface (one of the surfaces) of the first sheet first, and then the second sheet is made and bonded to the bottom surface of the sandwich structure. In another embodiment, the first sheet and the second sheet can also be made first, and then the sandwich structure is bonded between the two.

[0035] According to the required number of layers, repeat the operation to bond multiple sandwich structures between each first sheet and second sheet, or repeat the operation to bond multiple sandwich structures between part of the first sheets and second sheets. A multi-layer honeycomb-like composite energy-absorbing structure with different polygons can be obtained. By adjusting the folding method and quantity of the sandwich structure between the first sheet and the second sheet, changing the length of the adhesive tape and the side length of the sandwich structure, a honeycomb-like structure with various shape combinations can be obtained. For example, specifically, in one embodiment, a plurality of sandwich structures are bonded between each first sheet and the second sheet to obtain an octagonal and quadrilateral multi-layer honeycomb-like composite energy-absorbing structure. Bonding a plurality of sandwich structures between some of the first sheets and the second sheets can obtain a multi-layer honeycomb-like composite energy-absorbing structure with a mixture of octagons, hexagons, and quadrilaterals.

[0036] Specifically, in a specific embodiment, the length of the top and bottom surfaces of the sandwich structure is the same as the width of the adhesive tape, and the width of the area to be pasted on the first sheet and the second sheet is n times the width of the adhesive tape, where n ≥ 3. For example, when n is 3, it is an octagonal structure. Of course, in other embodiments, this width can be set as needed to obtain different polygonal structures. Bonding a plurality of sandwich structures between each first sheet and the second sheet can obtain a regular octagonal and square or mixed multi-layer honeycomb-like composite energy-absorbing structure. That is, the length of the folded side of the sandwich structure after stretching is the same as the length of the top and bottom surfaces, and the sandwich structure becomes a square after stretching.

[0037] S8. Apply a reverse tensile force to the first sheet and the last sheet to stretch open the folded sides of the sandwich structure to obtain a multi-layer honeycomb-like composite energy-absorbing structure.

[0038] Specifically, apply a reverse tensile force to the first sheet and the last sheet through a fixture to stretch open the folded sides of the sandwich structure to obtain a multi-layer honeycomb-like composite energy-absorbing structure.

[0039] Please refer to Figure 9 , during stretching, the cell stretching and forming process is as shown in a-b-c-d in Figure 9 . During the stretching process, the angle between the folded side of the sandwich structure and the top or bottom surface gradually increases, then approaches a quadrilateral, and finally forms a quadrilateral. When the length of the folded side is the same as the length of the top and bottom surfaces, a square is obtained. At the same time, during the stretching process, octagons are gradually formed between the four quadrilaterals.

[0040] The present invention also provides a multi-layer honeycomb-like composite energy-absorbing structure obtained according to the preparation method described above.

[0041] In one embodiment, the multi-layer honeycomb-like composite energy-absorbing structure is composed of octagons and quadrilaterals. Adjacent octagons are connected by quadrilaterals, and the sides of the quadrilaterals at the connection are co-edged with the sides of the octagons. In another embodiment, the multi-layer honeycomb-like composite energy-absorbing structure is composed of octagons, quadrilaterals, and hexagons. One set of opposite sides of the quadrilateral connects adjacent hexagons, and the other set of opposite sides connects adjacent octagons. The quadrilateral can be a square and a rectangle after stretching according to the lengths of the bottom side, the top side, and the folded side.

[0042] In one embodiment, the thickness of the sheet is 0.01 mm to 0.3 mm, and the sheet is a metal foil or an aramid paper.

[0043] Compared with the prior art, the beneficial effects of the present invention are as follows: The multi-layer honeycomb-like composite energy-absorbing structure obtained by the preparation method of the multi-layer honeycomb-like composite energy-absorbing structure of the present application, compared with the existing traditional honeycomb structure mainly composed of hexagons, the multi-layer honeycomb-like composite energy-absorbing structure obtained by the above method of the present application uses octagons as the main honeycomb cells of the honeycomb, and by introducing small cells (quadrilaterals or hexagons) in the node areas where the honeycomb cell walls intersect, local stress concentration during loading is reduced, and the occurrence area of the equivalent plastic strain of the structure during impact or compression is expanded, greatly improving the structural deformation mode. Compared with the traditional honeycomb structure of the same mass, due to the introduction of local improvement features in this structure, a significant increase in specific energy absorption during out-of-plane compression is achieved, which can be increased by more than 50%. Further, the above-mentioned staggered pasting is used to form a basic sheet unit, and the sheet to be pasted is cut and bent to form a foldable sandwich structure. The sandwich structure is first folded to form corresponding pasting edges and non-pasting edges, and various honeycomb shapes (such as octagons, hexagons, quadrilaterals) combined are obtained after stretching and unfolding after all pasting. The operation is simple and controllable, and the manufacturing cost is greatly reduced compared with the previous hierarchical and polygonal hybrid honeycomb structure forming schemes. At the same time, according to specific needs, the sandwich structure is pasted between some of the first sheets and the second sheets, and the sandwich structure is not provided between some of the first sheets and the second sheets. By adjusting the length of the pasting band and the side length of the sandwich structure, a honeycomb-like structure with a variety of specially customized shape combinations can be obtained.

Claims

1. A method for preparing a multi-layer honeycomb composite energy-absorbing structure, characterized in that: The steps include: The sheets to be pasted are cut and bent to form a foldable sandwich structure, wherein the sandwich structure has a top surface and a bottom surface of the same length, and a folded side in the middle, and the side is folded to fit with the top surface and the bottom surface, and the side is stretched to form a polygonal structure; Cutting a plurality of sheets of the same size and thickness; the sheets include a first sheet and a second sheet; Apply adhesive at equal intervals on the front surface of the first sheet to form first front adhesive tapes of a predetermined width, and form a first front area to be pasted between adjacent first front adhesive tapes; Apply adhesive at equal intervals on the back of the first sheet to form first back adhesive tapes of predetermined width, and form first back area to be pasted between adjacent first back adhesive tapes, and each first back adhesive tape is aligned with the center position of the first front area to be pasted; Apply adhesive at equal intervals on the front side of the second sheet to form second front side adhesive tapes of a predetermined width, and form a second front side area to be pasted between adjacent second front side adhesive tapes; Apply adhesive at equal intervals on the back of the second sheet to form second back adhesive tapes of predetermined width, and form a second back area to be pasted between adjacent second back adhesive tapes, and each second back adhesive tape is aligned with the first front adhesive tape of the previous layer, and each second front adhesive tape is aligned with the first back adhesive tape of the previous layer; Prepare a plurality of first sheets and second sheets, and bond a sandwich structure between each or a portion of the first sheets and second sheets, and align the top and bottom surfaces of the sandwich structure with the adhesive tapes of the first sheets and second sheets; A reverse tensile force is applied to the center of the area to be pasted of the first sheet and the last sheet to stretch the folded side of the sandwich structure to obtain a multi-layer honeycomb-like composite energy-absorbing structure.

2. The method for preparing a multi-layer honeycomb-like composite energy-absorbing structure according to claim 1, characterized in that: The sheet is cut and bent to form a foldable sandwich structure, and the connection ports are located on the top surface and the bottom surface. When the sandwich structure is bonded between the first sheet and the second sheet, the connection ports are bonded by adhesive tape.

3. The method for preparing a multi-layer honeycomb-like composite energy-absorbing structure according to claim 1, characterized in that: The lengths of the top and bottom surfaces of the sandwich structure are the same as the width of the adhesive tape, and the width of the area to be pasted of the first sheet and the second sheet is n times the width of the adhesive tape, where n≥3.

4. The method for preparing a multi-layer honeycomb-like composite energy-absorbing structure according to claim 1, characterized in that: The side of the sandwich structure is formed by multiple foldings, forming a jagged polygonal structure under incomplete stretching conditions; the folding form can be inner folding, outer folding or combined folding.

5. The method for preparing a multi-layer honeycomb-like composite energy-absorbing structure according to claim 4, characterized in that: By adjusting the folding mode and quantity of the sandwich structure between the first sheet and the second sheet, changing the length of the adhesive tape and the side length of the sandwich structure, a honeycomb-like structure with a variety of shape combinations can be obtained.

6. The method for preparing a multi-layer honeycomb-like composite energy-absorbing structure according to claim 1, characterized in that: A plurality of sets of stretching clamps with the same width as the adhesive tape are arranged at the center of the area to be pasted of the first sheet and the last sheet. The axial stretching movement and lateral movement of each clamp cooperate with each other to complete the stretching of the folded side of the sandwich structure and the bending forming of the sheet, thereby obtaining a multi-layer honeycomb composite energy-absorbing structure.

7. A multi-layer honeycomb-like composite energy-absorbing structure obtained according to the preparation method of claims 1-6.

8. The multi-layer honeycomb-like composite energy-absorbing structure according to claim 7, characterized in that: The multi-layer honeycomb-like composite energy-absorbing structure is composed of octagons and quadrilaterals. Adjacent octagons are connected by quadrilaterals, and the sides of the quadrilaterals and the sides of the octagons at the connection are coexistent.

9. The multi-layer honeycomb-like composite energy-absorbing structure according to claim 7, characterized in that: The multi-layer honeycomb-like composite energy-absorbing structure is composed of octagons, quadrangles and hexagons. One set of opposite sides of the quadrangles connects adjacent hexagons, and the other set of opposite sides connects adjacent octagons.

10. The multi-layer honeycomb-like composite energy absorbing structure according to claim 7, characterized in that: The thickness of the sheet material is 0.01 mm to 0.3 mm, and the sheet material is a metal foil or a thin paper sheet.

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