Bionic hierarchical multi-cell pipe energy absorption structure

Abstract

The invention relates to the technical field of automobile passive safety protection, in particular to a bionic hierarchical multi-cell pipe energy absorption structure which comprises a multi-cell circular pipe and bionic hierarchical structure units, the multi-cell circular pipe is composed of five partition plates and a circular pipe, and the multi-cell circular pipe with five cell elements is formed; each bionic hierarchical structure unit is composed of triangular hierarchical units, a triangle is formed by connecting the midpoints of two partition plates of each cell element and the midpoints of corresponding arcs, and the triangular hierarchical units are formed by parity of reasoning; the triangular hierarchical units are distributed in each cell element in a gradient mode from large to small in the radial direction, and the triangular hierarchical units of the adjacent cell elements are connected with each other. The bionic hierarchical multi-cell pipe energy absorption structure is stable in deformation in the collision compression process, the platform force fluctuation range is small, collision force can be effectively absorbed, and the safety of passengers is protected. According to the bionic hierarchical multi-cell tube energy absorption structure provided by the invention, under the condition that the structural quality is not changed, the energy absorption characteristic is increased along with the increase of hierarchical orders.

Description

Technical Field

[0001] The invention relates to the technical field of automobile passive safety protection, in particular to a bionic hierarchical multi-cellular tube energy absorption structure. Background Art

[0002] With the development of the automobile industry and the improvement of people's living standards, the number of cars in my country has increased rapidly. At the same time, casualties and property losses caused by traffic accidents remain high. When a car collides, the energy-absorbing structure absorbs energy through its own structural crushing and deformation, converts the kinetic energy of the collision into the internal energy of the structure, and evenly transmits the collision force to the two front longitudinal beams, playing a very important role in protecting the body structure and reducing occupant injuries. The load-bearing capacity of the energy-absorbing structure greatly affects the crashworthiness of the car. Therefore, designing a lightweight and highly crashworthy energy-absorbing structure is of great significance to improving the passive safety of the car.

[0003] Traditional energy-absorbing structures, including single tubes and multi-tubes of different shapes, have shortcomings such as poor energy absorption, large fluctuations in platform force, unstable deformation, and the contradiction between lightweight design and improved crash resistance during a collision, and cannot protect occupants well.

[0004] After tens of thousands of years of evolution and natural selection, organisms in nature have acquired excellent structural performance to adapt to different environments, which is nature's optimization of organisms. The use of bionic design theory to design multi-cell tube energy absorption structures provides new ideas for the design of automotive passive safety, especially collision-resistant energy absorption structures, and has great innovation value and research significance. Summary of the invention

[0005] In view of the problem that the existing multi-cellular tube structure has poor energy absorption performance, the present invention proposes a bionic hierarchical multi-cellular tube energy absorption structure. The present invention combines the bionic design theory and the crash-resistant structure design method, and selects the horsetail grass cross-section structure as the biological prototype for the optimized design of the multi-cellular tube through the principle of similarity. According to the structural and functional similarities between the horsetail grass cross-section structure and the multi-cellular tube, the triangular hierarchical unit is combined with the multi-cellular tube structure to design a new bionic hierarchical multi-cellular tube energy absorption structure with good crash resistance, which enhances the deformation stability of the multi-cellular tube structure and greatly improves the bearing capacity of the multi-cellular tube structure.

[0006] In order to achieve the above purpose, the technical solutions provided are as follows:

[0007] A bionic hierarchical multi-cellular tube energy absorption structure, characterized in that it includes a multi-cellular circular tube and a bionic hierarchical structure unit, wherein the multi-cellular circular tube is composed of five partitions and a circular tube to form a multi-cellular circular tube with five cells; the bionic hierarchical structure unit is composed of triangular hierarchical units, and a triangle is formed by connecting the midpoints of two partitions of each cell and the midpoints of corresponding arcs, and triangular hierarchical units are formed by analogy; the triangular hierarchical units are distributed in each cell in a gradient manner from large to small along the radial direction, and the triangular hierarchical units of adjacent cells are connected to each other.

[0008] Preferably, the five partitions are evenly distributed in the circular tube.

[0009] Preferably, the geometric dimensions of the triangular hierarchical units gradually decrease along the radial direction.

[0010] Preferably, the side lengths of the corresponding triangular hierarchical units in each cell are the same.

[0011] Preferably, the angles of the corresponding triangular hierarchical units in each cell are the same.

[0012] Preferably, the wall thickness of the partition and the circular tube is the same as the wall thickness of the triangular hierarchical unit.

[0013] Preferably, the bionic hierarchical multi-cellular tube energy absorption structure is made of metal.

[0014] Preferably, the bionic hierarchical multi-cellular tube energy-absorbing structure can be prepared by wire cutting or 3D printing technology.

[0015] Preferably, the bottom of the bionic hierarchical multi-cellular tube energy-absorbing structure is fixed to the front longitudinal beam, and the top of the bionic hierarchical multi-cellular tube energy-absorbing structure receives the impact of the collision resistance force.

[0016] The beneficial effects of the present invention are:

[0017] 1. The bionic hierarchical multi-cellular tube energy absorption structure provided by the present invention has novel design, simple structure, convenient processing, and is suitable for mass production requirements.

[0018] 2. The bionic hierarchical multi-cellular tube energy absorption structure provided by the present invention is constructed based on the gradient distribution of the cross-sectional structure of horsetail grass along the radial direction.

[0019] 3. The bionic hierarchical multi-cellular tube energy-absorbing structure provided by the present invention has stable deformation during the collision compression process, and the platform force fluctuation amplitude is small, which can effectively absorb the collision force and protect the safety of the occupants.

[0020] 4. The bionic hierarchical multi-cellular tube energy absorption structure provided by the present invention has an energy absorption characteristic that increases with the increase of the hierarchical order while ensuring that the structural mass remains unchanged, which further highlights the excellent energy absorption performance of the bionic hierarchical multi-cellular tube energy absorption structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic diagram of a multicellular circular tube structure of the present invention, wherein: Figure 1 a is a three-dimensional diagram of a multicellular circular tube. Figure 1 b is the cross-sectional view of a multicellular circular tube;

[0022] Figure 2 Schematic diagram of the first-order bionic hierarchical multi-cellular tube energy absorption structure in Example 1 of the present invention, wherein: Figure 2 a is a three-dimensional diagram of the first-order bionic hierarchical multi-cell tube energy absorption structure. Figure 2 b is the cross-sectional view of the first-order bionic hierarchical multi-cellular tube energy absorption structure.

[0023] Figure 3 Schematic diagram of the second-order bionic hierarchical multi-cellular tube energy absorption structure in Example 2 of the present invention, wherein: Figure 3 a is a three-dimensional diagram of the second-order bionic hierarchical multi-cell tube energy absorption structure. Figure 3 b is the cross-sectional view of the second-order bionic hierarchical multi-cellular tube energy absorption structure.

[0024] Figure 4 Schematic diagram of the energy absorption structure of the three-order bionic hierarchical multi-cellular tube in Example 3 of the present invention, wherein: Figure 4 a is a three-dimensional diagram of the three-order bionic hierarchical multi-cell tube energy absorption structure. Figure 4 b is the cross-sectional view of the third-order bionic hierarchical multi-cellular tube energy absorption structure.

[0025] Figure 5 This is a deformation diagram of the bionic hierarchical multi-cellular tube energy absorption structure of the present invention.

[0026] Figure 6 It is a force-displacement curve diagram of the bionic hierarchical multi-cellular tube energy-absorbing structure of the present invention. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Example 1

[0029] like Figures 1 to 4As shown, a bionic hierarchical multi-cellular tube energy absorption structure includes a multi-cellular circular tube and a bionic hierarchical structure unit; the multi-cellular circular tube is composed of five partitions and a circular tube to form a multi-cellular circular tube with five cells; the bionic hierarchical structure unit is composed of triangular hierarchical units, and a triangle is formed by connecting the two partitions of each cell and the midpoints of the corresponding arcs, and so on to form triangular hierarchical units; the triangular hierarchical units are gradiently distributed in each cell from large to small along the radial direction, and the triangular hierarchical units of adjacent cells are connected to each other.

[0030] All bionic hierarchical multi-cellular tube energy-absorbing structures involved in the present invention have an outer diameter of 150mm, a height of 220mm, and a mass of 279.92g. Under the condition of ensuring that the mass remains unchanged, the wall thickness of the structure changes with the change of the hierarchical order. The wall thicknesses of the multi-cellular circular tube, the first-order bionic hierarchical multi-cellular tube energy-absorbing structure, the second-order bionic hierarchical multi-cellular tube energy-absorbing structure, and the third-order bionic hierarchical multi-cellular tube energy-absorbing structure are 0.557mm, 0.301mm, 0.205mm, and 0.156mm, respectively.

[0031] like Figure 1 As shown, the multicellular circular tube is composed of five partitions 1 and a circular tube 2, forming a multicellular circular tube with five cells.

[0032] Example 2

[0033] like Figure 2 The first-order bionic hierarchical multi-cellular tube energy absorption structure shown is based on the multi-cellular circular tube. A triangle is formed by connecting the midpoints of the first first-order partition 11 and the second first-order partition 13 and the midpoints of the corresponding first-order arcs 12. Correspondingly, respective first-order triangular hierarchical units are formed in the five cells, ultimately forming a first-order bionic hierarchical multi-cellular tube energy absorption structure.

[0034] Example 3

[0035] like Figure 3 The second-order bionic hierarchical multi-cellular tube energy absorption structure shown is based on the first-order bionic hierarchical multi-cellular tube energy absorption structure. A second-order triangular hierarchical unit is formed by connecting the midpoints of the first second-order partition 21 and the second second-order partition 23 of each cell and the midpoints of the corresponding second-order arcs 22, thereby finally forming a second-order bionic hierarchical multi-cellular tube energy absorption structure.

[0036] Example 4

[0037] like Figure 4 The third-order bionic hierarchical multi-cellular tube energy absorption structure shown is based on the second-order bionic hierarchical multi-cellular tube energy absorption structure. A third-order triangular hierarchical unit is formed by connecting the midpoints of the first third-order partition 31 and the second third-order partition 33 of each cell and the midpoints of the corresponding third-order arcs 32, ultimately forming a third-order bionic hierarchical multi-cellular tube energy absorption structure.

[0038] Example 5 Numerical calculation of bionic hierarchical multi-cellular tube energy absorption structure

[0039] The pipe wall material is aluminum alloy, with Young's modulus E = 68GPa, Poisson's ratio ν = 0.33, and density ρ = 2.7×10 -3 kg / m 3 , yield stress σ y =71.0MPa, ultimate stress σ u =130.7MPa. The ABAQUS / Explicit explicit dynamics module is used for numerical calculation to establish a finite element model of the bionic hierarchical multi-cellular tube energy absorbing structure. The bottom end of the bionic hierarchical multi-cellular tube energy absorbing structure is fixed, and the indenter impacts the bionic hierarchical multi-cellular tube energy absorbing structure at a uniform speed of 10m / s. The indenter is meshed using discrete four-node rigid quadrilateral elements (R3D4), and the bionic hierarchical multi-cellular tube energy absorbing structure is meshed using four-node shell elements (S4R), with a mesh size of 1.5mm. The interaction between the indenter and the bionic hierarchical multi-cellular tube energy absorbing structure and the self-contact of the bionic hierarchical multi-cellular tube energy absorbing structure are set to general contact, the contact properties are set to penalty contact, the friction coefficient is 0.2, and the Isotropic material model is used to describe the physical properties of the bionic hierarchical multi-cellular tube energy absorbing structure. The deformation diagram, cross-sectional diagram, wrinkle line and wrinkle element of the bionic hierarchical multi-cellular tube energy absorbing structure are shown in Figure 2. Figure 5 As shown in the figure, with the increase of the order, the deformation of the bionic hierarchical multicellular tube energy absorption structure is more progressive, and the number of folds is also increasing. The number of folds of the multicellular circular tube and the middle partition of the bionic hierarchical multicellular tube energy absorption structure of different orders is 4, 10, 14, and 15 respectively. The force-displacement curve of the bionic hierarchical multicellular tube energy absorption structure is shown in the figure. Figure 6 As shown, with the increase of the order, the fluctuation amplitude of the curve gradually slows down, the platform force increases, and the specific energy absorption of the third-order bionic hierarchical multi-cellular tube energy absorption structure is 1.5 times that of the first-order bionic hierarchical multi-cellular tube energy absorption structure, which highlights the excellent energy absorption characteristics of the bionic hierarchical multi-cellular tube energy absorption structure.

[0040] Compared with the single-cell tube, the bionic hierarchical multi-cell tube energy-absorbing structure has a more stable deformation, can form more wrinkled units, and has a more gradual deformation process. The force-displacement curve of the bionic hierarchical multi-cell tube energy-absorbing structure has a smaller fluctuation amplitude and a larger platform force. The specific energy absorption of the third-order bionic hierarchical multi-cell tube energy-absorbing structure is 1.7 times that of the single-cell tube.

[0041] Compared with the multicellular tube, the bionic hierarchical multicellular tube energy absorption structure forms more wrinkle units, the number of wrinkles increases with the increase of the hierarchical order, and the platform force also increases with the increase of the order. The specific energy absorption of the third-order bionic hierarchical multicellular tube energy absorption structure is 1.4 times that of the multicellular tube.

[0042] Compared with other multicellular structures, see Table 1, which compares the energy absorption characteristics of different multicellular tube structures. To ensure the fairness of the comparison, all multicellular tubes have the same material parameters and mass (279.92g), different wall thicknesses (see Table 1), and the same loading speed, constraints and mesh division are used to calculate the energy absorption performance of all multicellular tube structures in Table 1. The results show that the bionic hierarchical multicellular tube energy absorption structure in the patent of this invention has a larger platform force and specific energy absorption.

[0043] Table 1 Comparison of energy absorption characteristics of different multicellular tube structures

[0044]

[0045] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A bionic hierarchical multi-cellular tube energy absorption structure, characterized in that: It includes a multicellular circular tube and a bionic hierarchical structure unit. The multicellular circular tube is composed of five partitions and a circular tube to form a multicellular circular tube with five cells. The bionic hierarchical structure unit is composed of triangular hierarchical units. A triangle is formed by connecting the midpoints of two partitions of each cell and the midpoints of corresponding arcs, and triangular hierarchical units are formed by analogy. The triangular hierarchical units are distributed in each cell in a gradient from large to small along the radial direction, and the triangular hierarchical units of adjacent cells are connected to each other.

2. The bionic hierarchical multi-cellular tube energy absorption structure according to claim 1, characterized in that: The five partitions are evenly distributed in the circular tube.

3. The bionic hierarchical multi-cellular tube energy absorption structure according to claim 1, characterized in that: The geometrical dimensions of the triangular hierarchical units gradually decrease along the radial direction.

4. The bionic hierarchical multi-cellular tube energy absorption structure according to claim 1, characterized in that: The side lengths of the corresponding triangular level units in each cell are the same.

5. The bionic hierarchical multi-cellular tube energy absorption structure according to claim 1, characterized in that: The angles of the corresponding triangle level units in each cell are the same.

6. The bionic hierarchical multi-cellular tube energy absorption structure according to claim 1, characterized in that: The wall thickness of the partition plate and the circular tube is the same as the wall thickness of the triangular hierarchical unit.

7. The bionic hierarchical multi-cellular tube energy absorption structure according to claim 1, characterized in that: The material of the bionic hierarchical multi-cellular tube energy absorption structure is metal.

8. The bionic hierarchical multi-cellular tube energy absorption structure according to claim 1, characterized in that: The bionic hierarchical multi-cellular tube energy absorption structure can be prepared by wire cutting or 3D printing technology.

9. The bionic hierarchical multi-cellular tube energy absorption structure according to claim 1, characterized in that: The bottom of the bionic layered multi-cellular tube energy absorbing structure is fixed to the front longitudinal beam, and the top of the bionic layered multi-cellular tube energy absorbing structure receives the impact of the collision resistance force.

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