Multi-cell energy absorption thin-walled tube based on paper folding structure

Abstract

The invention discloses a multi-cell energy-absorbing thin-walled tube based on a paper folding structure, which belongs to the technical field of structural mechanics and comprises a thin-walled inner tube, a thin-walled outer tube and a plurality of rib plates. Each layer of unit cell structure is defined by n unit wall plates in an end-to-end connection mode, each unit wall plate comprises an upper trapezoidal unit plate and a lower trapezoidal unit plate which are connected along a first crease, and the left side and the right side of each upper trapezoidal unit plate are connected with upper triangular unit plates along second creases correspondingly. The left side and the right side of the lower trapezoidal unit plate are respectively connected with the lower triangular unit plate along a third crease, and the upper triangular unit plate and the lower triangular unit plate are connected through a fourth crease. According to the multi-cell energy absorption thin-walled tube based on the paper folding structure, the thin-walled inner tube and the thin-walled outer tube which are of the paper folding structure are compounded through the rib plates, higher average crushing force is obtained through the compound design, and therefore the load stability of the structure is improved; the deformation process of the multi-cell energy-absorbing thin-walled tube is stable and controllable through specific crease lines and geometric shape design.

Description

Technical Field

[0001] The invention relates to a multi-cellular energy-absorbing thin-wall tube based on an origami structure, belonging to the technical field of structural mechanics. Background Art

[0002] Thin-walled tubular structures are widely used as energy-absorbing devices in the field of passive protection due to their lightweight and excellent mechanical properties. Through experiments, simulations and theoretical predictions, scholars have explored the mechanical properties of different thin-walled structures such as square, circular and polygonal structures. The results show that the energy absorption characteristics of thin-walled metal tubes are related to their structural design, loading mode, material properties and cross-sectional shape. A large number of experimental results show that traditional metal tubes usually deform in a symmetrical manner, with relatively low energy absorption performance, and only one moving plastic hinge line appears in each corner of a module. Therefore, in order to change the deformation mode of energy-absorbing devices and improve the energy absorption performance, porous tubes, foam-filled tubes, origami tubes, etc. have been further proposed. Among them, the energy absorption performance of origami tubes has attracted widespread attention. On the one hand, origami folds can reduce the initial stiffness of the tube, thereby reducing the initial peak force; on the other hand, studies have shown that most origami folds tend to become moving plastic hinge lines on metal tubes to absorb more energy. However, if the fold design is unreasonable, unstable deformation modes and uneven crushing forces are likely to occur during compression, resulting in large load fluctuations and instantaneous impacts.

[0003] For example, the automobile energy absorption box based on Yoshimura origami and its structural design method disclosed in the patent application with publication number CN114407819A utilizes an eight-row and eight-column Yoshimura origami folding pattern, in which each folding unit is composed of an isosceles trapezoid and an isosceles triangle, wherein the short base of the isosceles trapezoid is a mountain fold and the long base is a valley fold. The cross-section of the folded energy absorption body is a regular octagon, and the energy absorption body is fixed to the flange by welding. When the energy absorption box is impacted, the energy absorption body collapses under the induction of the folding, and wrinkles and deforms, thereby absorbing the energy generated by the impact. However, the energy absorption box belongs to a single-cell tube, and the controllability of the structure needs to be improved.

[0004] In the metal energy-absorbing thin-walled tube with negative Poisson's ratio effect and its design method disclosed in the patent application with publication number CN116608230A, the thin-walled tube is composed of a plurality of unit bodies fixedly connected end to end from top to bottom, each unit body includes a fixedly connected tube and a section, and when subjected to a compressive load, the metal tube shortens longitudinally and shrinks laterally, thereby achieving an energy-absorbing effect. In this patent application, the metal tube and the connected sections are set to different thicknesses, which enhances the bending strength. When the structure is compressed, it has a negative Poisson's ratio effect, and has a better energy-absorbing effect than ordinary metal tubes. However, this layered thickness gradient structure is not only not conducive to large-scale production, but also cannot bear large loads.

[0005] The multi-level energy absorption structure imitating a bird's nest disclosed in the patent application with publication number CN117429376A includes a polygonal tube, and multiple levels of energy absorption tubes are arranged inside the polygonal tube. The multiple levels of energy absorption tubes are staggered inward layer by layer, and the energy absorption tubes located in the outer layer are connected to the polygonal tube, and the adjacent levels of energy absorption tubes are fixedly connected; the energy absorption tubes are composed of multiple edges, and the edges that constitute the energy absorption tubes are cross-arranged at a set angle. During the collision process, the interaction between the layers of structures stacks and deforms to produce wrinkles, thereby achieving an energy absorption effect. However, the bionic design structure provided by the patent application is relatively complex, which greatly increases the weight of the structure, is not conducive to the improvement of the structural specific energy absorption, and is difficult to mass produce and apply in practice. Moreover, the patent application sequentially fills complex rectangular tubes, which have flat and continuous tube walls, without pre-existing deformation or wrinkles. When loading begins, a large force is required to reach the yield point to start plastic deformation, resulting in a very high overall initial peak force of the structure.

[0006] Therefore, it is of great research significance to improve the design strategy of thin-walled structures to improve load stability, reduce initial peak force, and increase specific energy absorption. Summary of the invention

[0007] In order to solve the problems existing in the prior art, the present invention provides a multi-cellular energy-absorbing thin-walled tube based on an origami structure, in which a thin-walled inner tube and a thin-walled outer tube with an origami structure are compounded through ribs, and the deformation process of the structure is stable and controllable through the design of specific crease lines and geometric shapes, and the energy absorption performance is more significant.

[0008] The present invention achieves the above-mentioned purpose by adopting the following technical solutions:

[0009] A multi-cell energy-absorbing thin-walled tube based on an origami structure, comprising a thin-walled inner tube, a thin-walled outer tube, and a plurality of ribs compositely connecting the thin-walled inner tube and the thin-walled outer tube; the thin-walled inner tube and the thin-walled outer tube are both composed of m layers of single-cell structures that are repeatedly connected in sequence along the axial direction of the tube, and the layer height h of the i-th layer of the single-cell structure of the thin-walled inner tube is the same as that of the i-th layer of the single-cell structure of the thin-walled outer tube, wherein i=1, ..., m, 1≤i≤m;

[0010] Each layer of the single-cell structure is formed by n unit wall plates connected end to end to enclose a tube, and the n unit wall plates form n intersecting edges; the n intersecting edges of the thin-walled inner tube and the n intersecting edges of the thin-walled outer tube are connected one by one through n ribs;

[0011] Each unit wall panel includes an upper trapezoidal unit panel and a lower trapezoidal unit panel whose short bottom edges are connected along a first fold, the left and right sides of the upper trapezoidal unit panel are respectively connected to an upper triangular unit panel along a second fold, the left and right sides of the lower trapezoidal unit panel are respectively connected to a lower triangular unit panel along a third fold, and the upper triangular unit panel and the lower triangular unit panel on each side are respectively connected by a fourth fold.

[0012] In a preferred embodiment, the upper triangular unit panels in the left and right adjacent unit wall panels are connected in the same plane, and the lower triangular unit panels in the left and right adjacent unit wall panels are connected in the same plane.

[0013] In a preferred embodiment, the first fold, the second fold, and the third fold are folds in the same direction and are in the opposite direction to the fourth fold.

[0014] In a preferred embodiment, the first fold, the second fold, and the third fold are mountain folds, and the fourth fold is a valley fold.

[0015] In a preferred embodiment, n=3-8; more preferably, n=4.

[0016] In a preferred embodiment, the n unit wall plates of the thin-walled inner tube and the n unit wall plates of the thin-walled outer tube are respectively arranged in parallel, and the thin-walled inner tube and the thin-walled outer tube are coaxially nested.

[0017] The external dihedral angle between the upper and lower adjacent trapezoidal unit plates or the upper and lower adjacent triangular unit plates in the thin-walled outer tube is θ, and the internal dihedral angle between the upper and lower adjacent trapezoidal unit plates or the upper and lower adjacent triangular unit plates in the thin-walled inner tube is β. In a preferred embodiment, 156°≤θ≤164°, 156°≤β≤164°, the number of layers of the unit cell structure is M, M=3 or 4; more preferably, θ=β.

[0018] The beneficial effects of this application include but are not limited to:

[0019] The multi-cell energy-absorbing thin-walled tube based on origami structure provided by the present invention is a composite of a thin-walled inner tube with origami structure and a thin-walled outer tube through ribs, and a higher average crushing force is obtained through composite design, thereby improving the load stability of the structure. Compared with the traditional structure, the structure of the present invention makes the deformation process of the multi-cell energy-absorbing thin-walled tube stable and controllable through specific crease lines and geometric shape design, and the energy absorption performance is more significant, which is reflected in:

[0020] (1) The trapezoidal unit plate and the triangular unit plate are connected along a specific crease line, which makes the deformation of the multi-cellular energy-absorbing thin-walled tube easier to control under the induction of the crease, allowing the multi-cellular energy-absorbing thin-walled tube to begin to deform at a lower stress level, so that the multi-cellular energy-absorbing thin-walled tube has a lower initial peak force, higher load stability and energy absorption characteristics; the lower initial peak force enables the multi-cellular energy-absorbing thin-walled tube to gradually absorb energy from the beginning of loading, and finally presents a complete diamond pattern, which improves the overall energy absorption capacity and promotes the stable and progressive deformation of the multi-cellular energy-absorbing thin-walled tube in the platform stage, with a continuous and stable energy absorption effect.

[0021] (2) It is convenient to optimize the structural stiffness by regulating the structural parameters of the multi-cellular energy-absorbing thin-walled tube and realize the high load stability and energy absorption characteristics of the multi-cellular energy-absorbing thin-walled tube. For example, by adjusting the longitudinal modulus, the structure can have more plastic hinges, which will produce more wrinkles under the action of axial load, thereby improving the energy absorption effect of the structure. Enlarging the dihedral angle can increase the area swept by the moving plastic hinge, thereby enhancing the energy absorption effect of the structure.

[0022] (3) The edge of the rib plate has the same dihedral angle as the thin-walled inner tube and the thin-walled outer tube, and the minimum rib structure is used to provide better performance while constraining the synchronous progressive deformation of the thin-walled inner tube and the thin-walled outer tube and minimizing the structural mass.

[0023] (4) The multi-cellular energy-absorbing thin-walled tube is simple in form, easy to manufacture, and low in cost. It can be manufactured through traditional stamping and welding processes and is suitable for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0025] Figure 1 is a schematic diagram of the unit cell structure;

[0026] Figure 2 It is a three-dimensional picture of a multi-cell energy-absorbing thin-walled tube;

[0027] Figure 3 It is a top view of the multi-cell energy-absorbing thin-walled tube;

[0028] Figure 4 Schematic diagram of the formation process of the unit cell structure;

[0029] Figure 5 Schematic diagram of the formation process of multi-cellular energy-absorbing thin-walled tubes;

[0030] Figure 6 It is a schematic diagram of the deformation of a multi-cell energy-absorbing thin-walled tube under uniaxial compression;

[0031] Figure 7 Schematic diagrams of four composite structures;

[0032] Figure 8 Force displacement curves and initial peak force curves of four composite structures;

[0033] Fig. 9 are the evaluation index results of the four composite structures;

[0034] Fig.10 The parameters of the external dihedral angle θ, internal dihedral angle β, and longitudinal modulus M are designed;

[0035] Fig.11 The parameter design value of thickness t and the schematic diagram of the effect of thickness t on energy absorption characteristics;

[0036] Fig.12 is the effect of the dihedral angle θ on the energy absorption characteristics;

[0037] Fig.13 is the influence of longitudinal modulus M on energy absorption characteristics;

[0038] Fig.14 The effect of the internal dihedral angle β on the energy absorption characteristics;

[0039] Fig.15 The energy absorption characteristics of DOT-D under different M and θ;

[0040] Fig.16 The variation curves of SEA and CFE, the evaluation indexes of DOT-D under different M and θ;

[0041] Fig.17 is the DOT-D evaluation index (F max , SEA, CFE) three-dimensional surface plot;

[0042] In the figure, 100, unit cell structure; 110, unit wall panel; 111, upper trapezoidal unit panel; 112, lower trapezoidal unit panel; 113, upper triangular unit panel; 114, lower triangular unit panel; 120, intersecting edges; 131, first crease; 132, second crease; 133, third crease; 134, fourth crease; 2, thin-walled inner tube; 3, thin-walled outer tube; 4, rib plate. DETAILED DESCRIPTION

[0043] In order to clearly illustrate the technical features of the present solution, the present invention is described in detail below through specific implementation methods and in conjunction with the accompanying drawings.

[0044] It should be noted that many specific details are described in the following description to facilitate a full understanding of the present invention, but the present invention can also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0045] like Figure 1-Figure 3 As shown in the figure, the multi-cell energy-absorbing thin-walled tube based on the origami structure provided by the present invention includes a thin-walled inner tube 2 and a thin-walled outer tube 3 arranged in a nested manner, and a plurality of ribs 4 for compositely connecting the thin-walled inner tube 2 and the thin-walled outer tube 3. Among them, the thin-walled inner tube 2 and the thin-walled outer tube 3 are both composed of m layers of single-cell structures 100 that are repeatedly connected in sequence along the axial direction of the tube. The layer height h of the i-th layer of the single-cell structure of the thin-walled inner tube 2 is the same as that of the i-th layer of the single-cell structure of the thin-walled outer tube, where i=1, ..., m, 1≤i≤m.

[0046] Each layer of the single-cell structure 100 is formed by n unit wall panels 110 connected end to end to enclose a tube, and the n unit wall panels 110 form n intersecting edges 120; the n intersecting edges of the thin-walled inner tube 2 and the n intersecting edges of the thin-walled outer tube 3 are connected one by one through n ribs 4.

[0047] Each unit wall panel 110 includes an upper trapezoidal unit panel 111 and a lower trapezoidal unit panel 112 whose short bottom edges are connected along a first fold 131; the left and right sides of the upper trapezoidal unit panel 111 are respectively connected to an upper triangular unit panel 113 along a second fold 132; the left and right sides of the lower trapezoidal unit panel 112 are respectively connected to a lower triangular unit panel 114 along a third fold 133; the upper triangular unit panel 113 and the lower triangular unit panel 114 on each side are respectively connected by a fourth fold 134.

[0048] Furthermore, the upper triangular unit panels in the left and right adjacent unit wall panels are connected in the same plane, and the lower triangular unit panels in the left and right adjacent unit wall panels are connected in the same plane.

[0049] Furthermore, the first fold 131 , the second fold 132 , and the third fold 133 are folds in the same direction, and are in the opposite direction to the fourth fold 134 .

[0050] Specifically, creases are divided into mountain creases and valley creases, where the mountain line is the crease that folds outward and the valley line is the crease that folds inward.

[0051] Furthermore, the n unit wall panels of the thin-walled inner tube 2 and the n unit wall panels 110 of the thin-walled outer tube 3 are respectively arranged in parallel.

[0052] The specific structural form and application effect of the multi-cellular energy-absorbing thin-walled tube based on the origami structure provided by the present invention will be introduced in detail below through specific embodiments.

[0053] Embodiment 1:

[0054] In Example 1, the thin-walled inner tube 2 and the thin-walled outer tube 3 are coaxially nested, and the layer height h of each layer of the unit cell structure 100 is equal, n=4.

[0055] The upper trapezoidal unit plate 111 and the lower trapezoidal unit plate 112 are both isosceles trapezoids, and the upper triangular unit plate 113 and the lower triangular unit plate 114 are right triangles.

[0056] The short bottom side of the upper trapezoidal unit plate and the short bottom side of the lower trapezoidal unit plate are connected along the first fold, and the waist length is equal to the hypotenuse length of the upper triangular unit plate and the lower triangular unit plate.

[0057] The two upper triangular unit plates and the two lower triangular unit plates in the left and right adjacent unit wall plates are connected coplanarly to form a diamond unit. The first fold, the second fold, and the third fold are mountain folds ( Figure 1 The fourth fold is the valley fold ( Figure 1 Therefore, in Example 1, the thin-walled inner tube 2 and the thin-walled outer tube 3 can also be regarded as being formed by an isosceles trapezoid mirror-symmetrical along the first fold 131 and an isosceles triangle mirror-symmetrical along the fourth fold 134, which are arranged in a repetitive pattern in the axial and circumferential directions.

[0058] like Figure 4 As shown in the figure, it is a schematic diagram of the formation process of the unit cell structure.

[0059] Specifically, Figure 4 As shown in (a), a rectangular structure with a total length of 4a and a total width of l is folded along the creases (solid lines represent mountain creases, and dotted lines represent valley creases) to obtain a unit cell structure as shown in Figure 4 As shown in (b), the length of the long base of the upper trapezoidal unit plate and the lower trapezoidal unit plate is a, and the length of the short base is c. In the rhombus unit formed by splicing the left and right adjacent unit wall panels, the length of the rhombus diagonal connected to the short base of the trapezoid is b, the layer height of the unit cell structure is h, and the corner of the two adjacent unit wall panels is

[0060] like Figure 4 As shown in (c), in the thin-walled outer tube, the outer dihedral angle formed between the upper trapezoidal unit plate and the lower trapezoidal unit plate, and between the upper triangular unit plate and the lower triangular unit plate is θ; in the thin-walled inner tube, the inner dihedral angle formed between the upper trapezoidal unit plate and the lower trapezoidal unit plate, and between the upper triangular unit plate and the lower triangular unit plate is β; Figure 4 As shown in (d), the longitudinal modulus M is the number of layers in the unit cell structure.

[0061] According to Figure 4 The method shown in the figure obtains the unit cell structures constituting the thin-walled inner tube and the thin-walled outer tube respectively, and then follows Figure 5The method shown utilizes ribs to compositely connect the thin-walled inner tube and the thin-walled outer tube, and repeatedly arranges them in the axial direction of the tube to form the multi-cell energy-absorbing thin-wall tube described in the present invention.

[0062] like Figure 6 , which is a schematic diagram of the deformation of the multi-cellular energy-absorbing thin-walled tube provided by the present invention under uniaxial compression (the percentage represents the displacement generated under the action of the axial load). It can be seen that when the multi-cellular energy-absorbing thin-walled tube provided by the present invention is subjected to external force, it relies on the non-stretching deformation of the fixed plastic hinge and the mobile plastic hinge and the surface tensile deformation to dissipate energy, and the overall structure is stably and gradually deformed under the induction of creases.

[0063] Through simulation and experiments, it can be found that the multi-cellular energy-absorbing thin-walled tube provided by the present invention has higher specific energy absorption and structural stability. This is because the multi-cellular energy-absorbing thin-walled tube provided by the present invention has more inner walls, which can produce more wrinkles during the collision process; and under the constraint of the rib structure, it can promote stable and progressive deformation inside the multi-cellular energy-absorbing thin-walled tube, which has better energy absorption, higher structural stability, and stronger anti-buckling and local failure capabilities.

[0064] When studying the energy absorption characteristics of multi-cell energy-absorbing thin-walled tubes, the main evaluation indicators are the initial peak force F max , average crushing force F m , the specific energy absorption SEA of the structure.

[0065] Where, initial peak force: F max , is the maximum force that the structure can withstand in the elastic stage during axial compression. Excessive initial peak force will directly lead to structural damage, so in engineering applications, the lower the initial peak force, the better.

[0066] Average crushing force: Where F is the crushing force of the structure during axial compression, and δ is the final displacement of the structure during axial compression.

[0067] The specific energy absorption of the structure: SEA, is the energy absorption capacity of the structure per unit mass. The higher the value, the better the energy absorption performance of the structure. The value can be obtained by the following formula:

[0068] Where EA is the total energy absorbed by the structure, and m is the weight of the structure.

[0069] CFE is used to evaluate the loading consistency during the crushing process; the higher the value, the more stable the structure and the better the impact resistance. m With F max The ratio of can be obtained, that is:

[0070] In the process of large deformation of structures and materials, energy dissipation exists in many forms, such as plastic dissipation energy, viscous deformation energy, friction or fracture dissipation energy, etc. In the above energy absorption mechanism, the energy dissipation caused by structural plastic deformation is mainly considered, and the geometric parameters have a significant impact on the plastic deformation of the structure. Specific to the present invention, energy dissipation mainly relies on four parts: fixed plastic hinges, movable plastic hinges, in-plane deformation of the tube, and in-plane deformation of the rib plate. Furthermore, the specific factors that have a major impact on the energy absorption effect of the multi-cell energy-absorbing thin-walled tube provided by the present invention are: the crease design of the external tube, the internal rib structure design, the internal tubular structure, the external dihedral angle θ, the internal dihedral angle β, the longitudinal modulus M and the wall thickness t of the unit wall panel.

[0071] In addition, in order to verify the excellent performance of the multi-cellular energy-absorbing thin-walled tube provided by the present invention, the applicant of the present invention studied four types of composite structures, namely, ribbed composite rhombus multi-cellular origami tube (DOT-D) (the present invention), ribbed composite square multi-cellular origami tube (DOT-S), ribbed composite X multi-cellular origami tube (DOT-X), and ribbed composite cross multi-cellular origami tube (DOT-C).

[0072] The following are the research results on the energy absorption characteristics of four different forms of composite structures, as well as the research results on the effect of geometric parameters on the plastic deformation of multi-cellular energy-absorbing thin-walled tube structures.

[0073] 1. Research results on energy absorption characteristics of four different forms of composite structures

[0074] The specific structural compositions of the four composite structures are as follows: Figure 7 As shown, the four composite structures adopt Figure 7 The same thin-walled outer tube structure shown in (a) is different in the structural form of the thin-walled inner tube and the rib plate.

[0075] in, Figure 7 (b) The rib composite rhombus multicellular origami tube (DOT-D) is a multicellular energy-absorbing thin-walled tube provided in Example 1 of the present invention. Figure 7 (c) In the ribbed composite square multicellular origami tube (DOT-S), the thin-walled inner tube is a rectangular tube, and the ribs are connected between the edges of the rectangular tube and the thin-walled outer tube; Figure 7 (d) In the rib-composite X-shaped origami tube (DOT-X), the diagonal edges of the thin-walled outer tube are connected by cross-shaped ribs; Figure 7 (e) In the rib-composite cross-cellular origami tube (DOT-C), the vertical center lines of the opposite unit wall panels in the thin-walled outer tube are connected by cross-shaped ribs.

[0076] Depend on Figure 8It can be seen that the mechanical properties of DOT-D are better than those of DOT-S, which has a rectangular tube inside. Analysis may be because under the action of load, the rectangular tube mainly absorbs energy through (symmetrical deformation) plastic deformation. The rectangular tube tends to deform at specific points where the stress concentration is the highest, causing these areas to bend or fold. This deformation usually occurs at local buckling points. Once these points fail, the structure may not be able to effectively absorb more energy; and this deformation is difficult to predict and uneven, so it is difficult to design for specific failure modes. The lack of an intermediate deformation mechanism will cause the structure to fail suddenly after the initial buckling, thereby reducing the overall energy absorption capacity of the structure. The geometric design of DOT-D provided in this application ensures that the deformation distribution of the entire structure is more uniform. Each fold is like a hinge that can rotate and deform, and absorbs energy over a larger deformation range by moving the area swept by the plastic hinge.

[0077] comprehensive Figure 8 and Fig. 9 It can be seen that the force-displacement curve of DOT-D is smoother than that of the other three composite structures, which means that the structural deformation of DOT-D during the collision is more stable, the impact force can be distributed more evenly, and the structural integrity can be better guaranteed. Since DOT-D has not only a rib plate structure design but also a tubular structure, the initial peak force of DOT-D is higher than the other two. However, it is precisely because of this design that the platform force of DOT-D is much higher than the other three composite structures, and SEA is also better than the other three composite structures. Fig. 9 The CFE situation in Figure 8 The force-displacement curves can prove that DOT-D has better structural stability than the other three composite structures.

[0078] 2. Research results on the effect of geometric parameters on the plastic deformation of multi-cell energy-absorbing thin-walled tube structures

[0079] Fig.10 The various geometric parameters are marked in the figure, and the specific parameter design values ​​of the external dihedral angle θ, the internal dihedral angle β, and the longitudinal modulus M are listed.

[0080] Figure 11-Figure 14 The structure of DOT-D shows that M, θ and β have a significant influence on F max The effect is not obvious, and CFE and SEA increase with the increase of M, θ and β. This shows that high M, θ and β bring high SEA and CFE, but too high M, θ and β can easily lead to the structure not being able to fold along the crease.

[0081] Therefore, for DOT-D, the optimal structure should be found in the range of 156°≤θ≤164°, 2≤M≤6, 158°≤β≤164° to obtain appropriately high SEA and CFE.

[0082] According to the above numerical results, multiple multi-cell energy-absorbing thin-walled tubes were designed under the conditions of 156°≤θ≤164°, M=3-6, t=1mm, and β=164°, and the energy absorption characteristics of DOT-D were further analyzed.

[0083] like Fig.15 As shown in , the total length of the fixed plastic hinge increases with the increase of M, and more wrinkles tend to form during deformation. However, when M ≥ 5, as Fig.15 The energy-absorbing multicellular thin-walled tubes of (i), (j), (k), and (l) only obtain three wrinkle blades in the axial direction, which does not reach the expected five wrinkles. This indicates that for origami multicellular tubes with the same θ, the complete diamond pattern is easier to be better followed in a smaller M.

[0084] M and θ and F of the origami tube max There is no correlation, indicating that M and θ do not affect the stiffness of the structure, and from Fig.17 It can be seen from (a) that F max The difference is not that big.

[0085] Fig.17 (b) It is observed that SEA shows an increasing trend in 156°≤θ≤164°, 2≤M<4. As θ and M further increase, the deformation mode changes from a complete rhombus mode to a non-complete rhombus mode, and then SEA gradually decreases. The SEA peak appears at the D_3_164 structure, which is 38.71% higher than D_2_156 and 107.40% higher than DOT.

[0086] Among them, the diamond mode refers to a buckling mode of the thin-walled tube structure under axial load. During the axial loading process, when the DOT-D deforms steadily and gradually along the crease and evenly forms a complete diamond area, a complete diamond pattern will appear, that is, the diamond mode deformation. Triggering the complete diamond mode means that the thin-walled tube deforms steadily and gradually along the crease during the collision, and all hinges and panels participate in energy absorption. At this time, the SEA and CFE of the structure are optimal.

[0087] Fig.17 (c) The same trend was observed, with a peak of CFE appearing at the D_3_164 structure, which was 16.70% higher than that of D_2_156.

[0088] The increase of θ expands the foldable angle of DOT-D, and the angle enclosed by the moving plastic hinge sweeps a larger area, which enhances the energy absorption effect of the multi-cell energy-absorbing thin-walled tube. When the thin-walled inner tube and the thin-walled outer tube have the same dihedral angle, the structure will have higher specific energy absorption and load stability.

[0089] The matters not described in detail in the present invention are all known technologies to those skilled in the art.

Claims

1. A multi-cell energy-absorbing thin-walled tube based on an origami structure, characterized in that: It comprises a thin-walled inner tube and a thin-walled outer tube which are nested, and a plurality of ribs which compositely connect the thin-walled inner tube and the thin-walled outer tube; the thin-walled inner tube and the thin-walled outer tube are both composed of m layers of unit cell structures which are repeatedly connected in sequence along the axial direction of the tube, and the i-th layer unit cell structure of the thin-walled inner tube has the same layer height h as the i-th layer unit cell structure of the thin-walled outer tube, wherein i=1, ..., m, 1≤i≤m; Each layer of the single-cell structure is formed by n unit wall plates connected end to end to enclose a tube, and the n unit wall plates form n intersecting edges; the n intersecting edges of the thin-walled inner tube and the n intersecting edges of the thin-walled outer tube are connected one by one through n ribs; Each unit wall panel includes an upper trapezoidal unit panel and a lower trapezoidal unit panel whose short bottom edges are connected along a first fold, the left and right sides of the upper trapezoidal unit panel are respectively connected to an upper triangular unit panel along a second fold, the left and right sides of the lower trapezoidal unit panel are respectively connected to a lower triangular unit panel along a third fold, and the upper triangular unit panel and the lower triangular unit panel on each side are respectively connected by a fourth fold.

2. The multi-cell energy-absorbing thin-walled tube based on origami structure according to claim 1 is characterized in that: The upper triangular unit plates in the left and right adjacent unit wall plates are connected in a coplanar manner, and the lower triangular unit plates in the left and right adjacent unit wall plates are connected in a coplanar manner.

3. The multi-cell energy-absorbing thin-walled tube based on origami structure according to claim 1 is characterized in that: The first fold, the second fold and the third fold are folds in the same direction and are in the opposite direction to the fourth fold.

4. The multi-cell energy-absorbing thin-walled tube based on origami structure according to claim 1 is characterized in that: The first fold, the second fold and the third fold are mountain folds, and the fourth fold is a valley fold.

5. The multi-cell energy-absorbing thin-walled tube based on origami structure according to claim 1 is characterized in that: n＝3～8。 6. The multi-cell energy-absorbing thin-walled tube based on origami structure according to claim 1 is characterized in that: n＝4。 7. The multi-cell energy-absorbing thin-walled tube based on origami structure according to claim 1 is characterized in that: The n unit wall plates of the thin-walled inner tube and the n unit wall plates of the thin-walled outer tube are respectively arranged in parallel, and the thin-walled inner tube and the thin-walled outer tube are coaxially nested.

8. The multi-cell energy-absorbing thin-walled tube based on origami structure according to claim 1 is characterized in that: The outer dihedral angle between the upper and lower adjacent trapezoidal unit plates or the upper and lower adjacent triangular unit plates in the thin-walled outer tube is θ, and the inner dihedral angle between the upper and lower adjacent trapezoidal unit plates or the upper and lower adjacent triangular unit plates in the thin-walled inner tube is β, 156°≤θ≤164°, 156°≤β≤164°, and the number of layers of the unit cell structure is M, M=3 or 4.

9. The multi-cell energy-absorbing thin-walled tube based on origami structure according to claim 8, characterized in that: θ=β.

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