Gradient dot matrix filling thin-wall energy-absorbing device

Abstract

The application relates to the field of automobile safety technology and discloses a gradient dot array filling thin-wall energy-absorbing device, which comprises a pipe body and an energy-absorbing assembly. The energy-absorbing assembly comprises a plurality of dot array layers, the plurality of dot array layers are embedded in the pipe body in the axial direction, and adjacent two dot array layers are fixedly connected. The dot array layer comprises a first single cell, a plurality of second single cells and a plurality of third single cells. The first single cell is located on the axis of the pipe body, the number of the plurality of second single cells and the plurality of third single cells is consistent, the plurality of second single cells and the plurality of third single cells are fixedly connected at equal intervals in the circumferential direction on the outer circle of the first single cell, and the plurality of second single cells and the plurality of third single cells are staggered and arranged, adjacent two second single cells and third single cells are fixedly connected, and are embedded on the inner wall of the pipe body. The gradient mode of the application can obtain more wrinkles through interaction with the pipe body, thereby having excellent crashworthiness.

Description

Technical Field

[0001] This invention relates to the field of automotive safety technology, and in particular to a gradient lattice filled thin-walled energy absorption device. Background Technology

[0002] Automotive energy-absorbing boxes serve as a low-speed safety protection system and are prone to wrinkling and deformation during collisions. Energy-absorbing boxes are mostly thin-walled metal tubes, which improve passive safety and reduce maintenance costs. Therefore, achieving both high energy absorption and lightweight design has always been a goal in ensuring automotive safety.

[0003] Therefore, to improve the impact resistance of energy-absorbing boxes, there is an urgent need for a lightweight filler that can enhance the energy absorption effect of thin-walled tube structures. However, traditional foam and honeycomb structures are complex to process and rarely used in practice. With the rapid development of additive manufacturing technology, many complex lightweight porous lattices have been fabricated. Therefore, this problem can be solved by embedding gradient lattices. Summary of the Invention

[0004] The purpose of this invention is to provide a gradient lattice filled thin-walled energy absorption device to solve the problems existing in the prior art.

[0005] To achieve the above objectives, the present invention provides the following solution: The present invention provides a gradient lattice filled thin-walled energy absorption device, comprising:

[0006] tube body;

[0007] An energy-absorbing component includes several lattice layers, which are axially embedded in the tube body and are fixedly connected to adjacent lattice layers.

[0008] The lattice layer includes a first unit cell, a plurality of second unit cells, and a plurality of third unit cells. The first unit cell is located on the axis of the tube. The number of the plurality of second unit cells and the plurality of third unit cells are the same. The plurality of second unit cells and the plurality of third unit cells are fixedly connected to the outer ring of the first unit cell at equal intervals along the circumference. The plurality of second unit cells and the plurality of third unit cells are staggered. Adjacent second unit cells and third unit cells are fixedly connected and respectively embedded in the inner wall of the tube.

[0009] Preferably, the first unit cell, the second unit cell, and the third unit cell are each composed of a plurality of rods, and adjacent rods on the first unit cell, the second unit cell, and the third unit cell are fixedly connected.

[0010] Preferably, the first unit cell and the third unit cell are located on the same axis, and the two adjacent rods form a type I gradient lattice or a type II gradient lattice along the direction from the center of the first unit cell to the axis of the tube.

[0011] Preferably, the lattice density expression (a) inside the tube (1) is as follows:

[0012]

[0013] Where ρ is the density of the filling structure, ρ max For maximum density, ρ min The minimum density is given, while the maximum and minimum densities are constants.

[0014] Preferably, the cross-section of the rod is circular, and the radius expression (b) of the rod in the Type I gradient lattice and the Type II gradient lattice is as follows:

[0015]

[0016] Where r max It is the maximum value of the rod's radius, r min It is the minimum value of the rod radius, L is 1 / 2 of the diagonal length of the trapezoidal cross section, and x is any position on the edge of the lattice cross section;

[0017] For a type I gradient lattice, when x is at 2-1, i.e., x is located at the edge of the lattice section, x / L = 0, r(x) = r max When x is at position 2-4, i.e., x is located in the middle of the lattice section, x / L = 1, r(x) = r min ;

[0018] For a type II gradient lattice, when x is at 2-1, i.e., x is located at the edge of the lattice section, x / L = 0, r(x) = r min When x is at position 2-4, i.e., x is located in the middle of the lattice section, x / L = 1, r(x) = r max .

[0019] Preferably, the tube body is a square thin-walled tube.

[0020] Preferably, there are four second unit cells and four third unit cells, with the four second unit cells located at the four corners of the square thin-walled tube and the four third unit cells located on the four sides of the square thin-walled tube.

[0021] Preferably, the number of rods on the first unit cell, the second unit cell, and the third unit cell is eight, and the eight rods form a body-centered cubic structure.

[0022] Compared with the prior art, the present invention has the following advantages and technical effects:

[0023] This invention provides a gradient lattice-filled thin-walled energy-absorbing device, in which several lattice layers are periodically embedded in a tube to ensure that the lattice layers do not slide relative to the inner wall of the tube. The gradient pattern of the lattice has two variations: one where the radius gradually decreases from the edge inwards, and the other where it gradually increases. These two gradient patterns, through interaction with the tube, generate more wrinkles, thus exhibiting excellent impact resistance. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the tube structure of the present invention;

[0026] Figure 2 This is a schematic diagram of the energy-absorbing component structure of the present invention;

[0027] Figure 3 This is a schematic diagram of the overall structure of the device of the present invention;

[0028] Figure 4 This is a schematic diagram of the unit cell structure of the present invention, wherein ① is the second unit cell, ② is the third unit cell, and ③ is the first unit cell;

[0029] Figure 5 This is a schematic diagram of the distribution of unit cells within the lattice layer of the present invention;

[0030] Figure 6 This is a schematic diagram of the Type I gradient structure of the present invention;

[0031] Figure 7 This is a schematic diagram of the type II gradient structure of the present invention;

[0032] Figure 8 This is a schematic diagram illustrating the stress changes in the device of the present invention;

[0033] Among them, 1. tube body; 2. first unit cell; 3. second unit cell; 4. third unit cell. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] Example 1:

[0037] Reference Figures 1-7 The present invention provides a gradient lattice filled thin-walled energy absorption device, comprising:

[0038] tube body 1;

[0039] The energy-absorbing component includes several lattice layers, which are embedded axially inside the tube 1, and adjacent lattice layers are fixedly connected.

[0040] The lattice layer includes a first unit cell 2, several second unit cells 3 and several third unit cells 4. The first unit cell 2 is located on the axis of the tube 1. The number of the several second unit cells 3 and several third unit cells 4 is the same. The several second unit cells 3 and several third unit cells 4 are fixedly connected to the outer ring of the first unit cell 2 at equal intervals along the circumference. The several second unit cells 3 and several third unit cells 4 are staggered. Adjacent two second unit cells 3 and three unit cells 4 are fixedly connected and respectively embedded in the inner wall of the tube 1.

[0041] In a further optimized design, the first unit cell 2, the second unit cell 3, and the third unit cell 4 are each composed of several rods, and adjacent rods on the first unit cell 2, the second unit cell 3, and the third unit cell 4 are fixedly connected.

[0042] Further optimization of the scheme: the first unit cell 2 and the third unit cell 4 are located on the same axis. The two adjacent rods form a type I gradient lattice or a type II gradient lattice along the axis from the center of the first unit cell 2 to the center of the tube 1.

[0043] The further optimized scheme is shown in expression (a) for the lattice density inside tube 1 as follows:

[0044]

[0045] Where ρ is the density of the filling structure, ρ max For maximum density, ρ min The minimum density is given, while the maximum and minimum densities are constants.

[0046] x is the length from the edge of the lattice (node ​​2-1) to any position on the diagonal, and L is half the length of the entire diagonal.

[0047] Further optimization of the scheme: the cross-section of the rod is circular. The radius expressions (b) of the rod in the Type I gradient lattice and Type II gradient lattice are as follows:

[0048]

[0049] Where r max It is the maximum value of the rod's radius, r min It is the minimum value of the rod radius, L is 1 / 2 of the diagonal length of the trapezoidal cross section, and x is any position on the edge of the lattice cross section;

[0050] For a type I gradient lattice, when x is at 2-1, i.e., x is located at the edge of the lattice section, x / L = 0, r(x) = r max When x is at position 2-4, i.e., x is located in the middle of the lattice section, x / L = 1, r(x) = r min ;

[0051] For a type II gradient lattice, when x is at 2-1, i.e., x is located at the edge of the lattice section, x / L = 0, r(x) = r min When x is at position 2-4, i.e., x is located in the middle of the lattice section, x / L = 1, r(x) = r max .

[0052] Reference Figure 6 For a type I gradient lattice, when x is at 2-1, i.e., x is located at the edge of the lattice section, x / L=0, r(x)=r max When x is at position 2-4, i.e., x is located in the middle of the lattice section, x / L = 1, r(x) = r min ;

[0053] Reference Figure 7 For a type II gradient lattice, when x is at 2-1, i.e., x is located at the edge of the lattice section, x / L=0, r(x)=r min When x is at position 2-4, i.e., x is located in the middle of the lattice section, x / L = 1, r(x) = r max .

[0054] Further optimization of the design: tube 1 is a square thin-walled tube.

[0055] The scheme was further optimized so that there are four second unit cells 3 and four third unit cells 4. The four second unit cells 3 are located at the four corners of the square thin-walled tube, and the four third unit cells 4 are located on the four sides of the square thin-walled tube.

[0056] Reference Figure 2 , Figure 3 There are a total of 9 units: the first unit 2, the second unit 3, and the third unit 4. The 9 units are arranged in a 3x3 grid. The four second unit 3 units are located at the four corners of the 3x3 grid, the four third unit 4 units are located on the four sides of the 3x3 grid, and the first unit 2 is located in the center. The overall structure is suitable for square thin-walled tubes.

[0057] Specific references Figure 5The first unit cell 2 is located in the center. The second unit cell 3 in the upper left corner and the third unit cell 4 directly above it are the initial positions. Starting from the second unit cell 3 in the upper left corner, they are arranged clockwise as follows: the third unit cell 4, the second unit cell 3 rotated 90° clockwise, the third unit cell 4 rotated 90° clockwise, the second unit cell 3 rotated 180° clockwise / counterclockwise, the third unit cell 4 rotated 180° clockwise / counterclockwise, the second unit cell 3 rotated 90° counterclockwise, and the third unit cell 4 rotated 90° counterclockwise. Additionally, refer to... Figures 6-7 The second unit cell (section 3) at the top left corner has a trapezoidal rod at the bottom right corner, and the third unit cell (section 4) directly above has rods of the same diameter, thus obtaining the entire lattice layer. This ensures that the trapezoidal structure is distributed from the four corners towards the center. Additionally, refer to... Figure 6 The type I gradient lattice has a rod diameter that gradually decreases from the outside to the inside, as shown in the reference. Figure 7 The type II gradient lattice has a rod diameter that gradually increases from the outside to the inside.

[0058] The scheme is further optimized so that the number of rods on the first unit cell 2, the second unit cell 3, and the third unit cell 4 is eight, and the eight rods form a body-centered cubic structure.

[0059] Reference Figure 4 Each unit cell consists of eight rods, with one end of each rod fixedly connected and the other end distributed outwards at an angle, forming a body-centered cubic structure. In addition, the other end of each rod has a characteristic shape. Adjacent rods between two adjacent unit cells are spliced ​​together and fixedly connected through the characteristic shape to form an integral structure.

[0060] Example 2:

[0061] Reference Figure 8 The material of tube body 1 is Al-1060, and the material of energy absorption component is AlSi10Mg alloy. The elastic modulus of Al-1060 is E1 = 64.8 GPa, Poisson's ratio μ1 = 0.30, and the initial yield strength is σ1 = 45 MPa. The elastic modulus of AlSi10Mg alloy is E2 = 62.9 GPa, Poisson's ratio μ2 = 0.30, and the initial yield strength is σ2 = 125 MPa.

[0062] A model was built in the finite element software ABAQUS / Explict. The tube body 1 is made of Al-1060, with a height of L1 = 120 mm and a cross-sectional dimension of a1 × b1 = 30 mm × 30 mm. The energy-absorbing component is made of AlSi10Mg alloy, with a height of L2 = 120 mm and a cross-sectional dimension of a2 × b2 = 30 mm × 30 mm. The maximum rmax and minimum radius rmin of the Type I gradient are 0.54 mm and 0.20 mm, respectively, while those of the Type II gradient are 0.9 mm and 0.42 mm, respectively. The m=3 value is used for both Type I and Type II gradients, and the two gradient modes have the same mass.

[0063] Taking one of the lattice layers as an example, it consists of 9 unit cells, including a single first unit cell 2, a single second unit cell 3, and a single third unit cell 4. The unit cells at the remaining positions are obtained by rotation and translation using the method in Embodiment 1, and the radius of the rods at the nodes remains consistent. Viewed from the z-direction, the nodes covered by the black dots have the same radius in each layer.

[0064] The tube body 1 of the gradient lattice-filled thin-walled energy-absorbing box device is prepared by wire cutting technology, and the gradient lattice is prepared by laser melting technology.

[0065] Reference Figure 8 This is a schematic diagram showing the stress variation of the gradient lattice filled thin-walled energy-absorbing box device in this invention under different compression distances.

[0066]

[0067]

[0068] As can be observed from the table, the experimental and simulation errors are within 5.00%. The total energy absorption of I-RLT is 5.78% higher than that of U-RLT (experimental), and the total energy absorption of II-RLT is 9.91% higher than that of U-RLT (experimental). However, the initial peak breaking force is only increased by about 2.00%, and the impact efficiency of the gradient lattice filled thin-walled energy-absorbing structure designed in this patent is also above 0.7. Therefore, the gradient lattice design can achieve a lower initial peak load while increasing energy absorption.

[0069] Reference Figure 8As can be observed from the figure, some of the wrinkles obtained in the experiment started from the top, and others from the bottom. The location of the first wrinkle is related to the location of the initial defect in tube 1, and the number of wrinkles is related to the number of internal lattice points. Because the more lattice points there are, the more complex the contact with the inner wall of tube 1, resulting in more wrinkles, shorter wavelengths of the wrinkles, and better energy absorption. All wrinkles develop from the formation of the previous wrinkle to the formation of the next wrinkle, thus forming a progressive deformation mode. This deformation mode is an overall buckling effect, which is a relatively ideal folding method.

[0070] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0071] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A gradient lattice-filled thin-walled energy absorption device, characterized in that, include: tube body(1); The energy-absorbing component includes several lattice layers, which are axially embedded in the tube (1) and are fixedly connected to each other. The lattice layer includes a first unit cell (2), a plurality of second unit cells (3) and a plurality of third unit cells (4). The first unit cell (2) is located on the axis of the tube (1). The number of the plurality of second unit cells (3) and the plurality of third unit cells (4) is the same. The plurality of second unit cells (3) and the plurality of third unit cells (4) are fixedly connected to the outer ring of the first unit cell (2) at equal intervals along the circumference. The plurality of second unit cells (3) and the plurality of third unit cells (4) are staggered. Adjacent second unit cells (3) and third unit cells (4) are fixedly connected and respectively embedded on the inner wall of the tube (1).

2. The gradient lattice filled thin-walled energy absorption device according to claim 1, characterized in that: The first unit cell (2), the second unit cell (3), and the third unit cell (4) are each composed of several rods, and adjacent rods on the first unit cell (2), the second unit cell (3), and the third unit cell (4) are fixedly connected.

3. The gradient lattice filled thin-walled energy absorption device according to claim 2, characterized in that: The first unit cell (2) and the third unit cell (4) are located on the same axis. The two adjacent rods form a type I gradient lattice or a type II gradient lattice along the axis from the center of the first unit cell (2) to the center of the tube (1).

4. The gradient lattice filled thin-walled energy absorption device according to claim 3, characterized in that: The expression (a) for the lattice density inside the tube (1) is as follows: Where ρ is the density of the filling structure, ρ max For maximum density, ρ min The minimum density is given, while the maximum and minimum densities are constants.

5. The gradient lattice filled thin-walled energy absorption device according to claim 3, characterized in that: The cross-section of the rod is circular, and the radius expression (b) of the rod in the Type I gradient lattice and the Type II gradient lattice is as follows: Where r max It is the maximum value of the rod's radius, r min It is the minimum value of the rod radius, L is 1 / 2 of the diagonal length of the trapezoidal cross section, and x is any position on the edge of the lattice cross section; For a type I gradient lattice, when x is at 2-1, i.e., x is located at the edge of the lattice section, x / L = 0, r(x) = r max When x is at position 2-4, i.e., x is located in the middle of the lattice section, x / L = 1, r(x) = r min ; For a type II gradient lattice, when x is at 2-1, i.e., x is located at the edge of the lattice section, x / L = 0, r(x) = r min When x is at position 2-4, i.e., x is located in the middle of the lattice section, x / L = 1, r(x) = r max .

6. The gradient lattice filled thin-walled energy absorption device according to claim 5, characterized in that: The tube body (1) is a square thin-walled tube.

7. The gradient lattice filled thin-walled energy absorption device according to claim 6, characterized in that: There are four of each of the second unit cell (3) and the third unit cell (4). The second unit cell (3) is located at the four corners of the square thin-walled tube, and the third unit cell (4) is located on the four sides of the square thin-walled tube.

8. The gradient lattice filled thin-walled energy absorption device according to claim 7, characterized in that: The number of rods on the first unit cell (2), the second unit cell (3), and the third unit cell (4) is eight, and the eight rods form a body-centered cubic structure.

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