Energy absorbing element and lattice energy absorbing structure thereof

Abstract

The present invention discloses an energy absorbing element and a lattice energy absorbing structure thereof, including two frustums, each of which includes a first surface, a second surface and a side surface, the first surface and the second surface are arranged opposite to each other up and down, the side surface is arranged between the first surface and the second surface, the area of ​​the second surface is larger than the first surface, the two frustums are located at one end of the second surface and fixedly connected to form an integrated structure, a cavity is arranged inside the frustum, and the first surface and the second surface are both provided with holes connected to the cavity. The lattice structure of the present invention deforms and collapses in a stable and controllable manner. Compared with other structures such as multicellular tubes, the lattice structure of the present invention has no initial peak force under quasi-static compression conditions, and the force shows a stable change trend with displacement. Since the deformation of the lattice structure is stable, its crushing force is always maintained at the platform value, and a quasi-rectangular energy absorption curve is presented within the effective displacement range. In addition, changing the cell size can control the compression ratio, which is convenient for the precise control of the energy absorption process.

Description

Technical Field

[0001] The present invention relates to the technical field of buffering and energy absorption, and in particular to an energy absorption element and a lattice energy absorption structure thereof. Background Art

[0002] In response to the call for green energy conservation, the control of equipment weight in the fields of packaging, aerospace, rail transportation, etc. has gradually become an important design guideline. As an ordered porous material, the lattice structure can not only optimize its microstructure according to different application requirements while maintaining a high porosity, but also ensure good specific stiffness and specific strength. Therefore, compared with traditional thin-walled structures, the lattice structure can achieve the regulation of mechanical properties in specific application environments while ensuring personalized design.

[0003] According to the different microstructure construction forms, lattice structures are divided into two-dimensional and three-dimensional lattice structures. The two-dimensional lattice structure is a honeycomb structure obtained by stretching the polygons arranged in a plane in the third direction; the three-dimensional lattice structure is a spatial truss structure composed of rods, plates and other elements arranged in space according to certain rules. Among them, the honeycomb structure is an important energy absorber, and the topological configuration, structural parameters and load type have an important influence on its mechanical properties. However, these studies have found that under external loads, the honeycomb structure may produce an uncontrollable collapse mode, with a higher maximum initial peak load value and a large fluctuation range of the load-displacement diagram, which is not conducive to precise control. Summary of the invention

[0004] The object of the present invention is to provide an energy absorbing element and a lattice energy absorbing structure thereof, so as to solve the above-mentioned problems.

[0005] To achieve the above-mentioned purpose, the present invention first discloses an energy absorbing element, including two frustums, each of which includes a first surface, a second surface and a side surface, the first surface and the second surface are arranged opposite to each other up and down, the side surface is surrounded between the first surface and the second surface, the area of ​​the second surface is larger than that of the first surface, the two frustums are located at one end of the second surface and fixedly connected to form an integrated structure, a cavity is arranged inside the frustum, and the first surface and the second surface are both provided with a hole connected to the cavity.

[0006] Furthermore, the frustum is a prism structure in which the first surface and the second surface are parallel.

[0007] Furthermore, the pyramid is a quadrangular pyramid, the first face and the second face of the quadrangular pyramid are square or rectangular, and the side face is a trapezoid.

[0008] Furthermore, the first and second surfaces of the frustum are square, the side surface is an isosceles trapezoid, and the holes penetrating through the cavity on the first and second surfaces are both square holes.

[0009] Furthermore, the cavity is a frustum-shaped cavity that penetrates the first surface and the second surface at the upper and lower sides.

[0010] Furthermore, the frustum is a circular frustum whose first surface and second surface are parallel and circular.

[0011] Furthermore, the two frustums are integrally formed by 3D printing.

[0012] Then, the present invention discloses a lattice energy absorbing structure, comprising a plurality of energy absorbing elements described in the above scheme, wherein the vertically adjacent energy absorbing elements are fixedly connected together at one end close to the first surface, and the laterally adjacent energy absorbing elements are fixedly connected together near the middle of the second surface.

[0013] Furthermore, the energy absorbing elements are arranged in an array along three directions of space to form a quadrangular pyramid lattice structure.

[0014] Furthermore, the tetrahedral lattice structure is integrally formed by 3D printing.

[0015] Compared with the prior art, the advantages of the present invention are:

[0016] The lattice structure of the present invention deforms and collapses in a stable and controllable manner. Compared with other structures such as multicellular tubes, the lattice structure of the present invention has no initial peak load under quasi-static compression conditions, and the crushing force shows a stable change trend with displacement. Since the deformation of the lattice structure is stable, its crushing force is always maintained at a platform value, and a quasi-rectangular energy absorption curve is presented within the effective displacement range. In addition, the compression ratio of the tetrahedral lattice structure can be controlled by changing the cell size, which facilitates the precise control of the energy absorption process.

[0017] The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0019] Figure 1 It is a front view of the energy absorbing element disclosed in the embodiment of the present invention;

[0020] Figure 2 A top view of an energy absorbing element disclosed in an embodiment of the present invention;

[0021] Figure 3 A diagram of a frustum of an energy absorbing element disclosed in an embodiment of the present invention;

[0022] Figure 4 An axonometric diagram of a lattice structure disclosed in an embodiment of the present invention;

[0023] Figure 5 It is a front view of the lattice energy absorption structure disclosed in an embodiment of the present invention;

[0024] Figure 6 for Figure 5 AA section view.

[0025] Figure 7 It is a three-dimensional schematic diagram of the multicellular tube structure;

[0026] Figure 8 It is a schematic diagram of the front view of the multicellular tube structure;

[0027] Fig. 9 This is a schematic diagram of the axial compression finite element simulation of the multi-cell tube structure;

[0028] Fig.10 It is a schematic diagram of axial compression finite element simulation of a tetrahedral lattice structure;

[0029] Fig.11 It is the axial compression crushing force curve diagram of the multi-cell tube structure and the tetrahedral lattice structure;

[0030] Legend:

[0031] 1. Cone; 11. First surface; 12. Second surface; 13. Side surface; 14. Cavity. DETAILED DESCRIPTION

[0032] The embodiments of the present invention are described in detail below with reference to the accompanying drawings, but the present invention can be implemented in many different ways as defined and covered by the claims.

[0033] like Figure 1-6 As shown, the present invention first discloses an energy absorbing element, including two frustums 1, wherein the frustum 1 can be a circular frustum or a multi-sided frustum structure such as a triangular frustum, a quadrangular frustum, a pentagonal frustum, etc. In this embodiment, the frustum 1 adopts a quadrangular frustum, so as to facilitate the subsequent formation of a stable spatial structure. The frustum 1 includes a first surface 11, a second surface 12 and a side surface 13, the first surface 11 and the second surface 12 are opposite to each other up and down, the side surface 13 is surrounded between the first surface 11 and the second surface 12, the area of ​​the second surface 12 is larger than the first surface 11, the frustum 1 is a structure in which the first surface 11 and the second surface 12 are interlinked, and a cavity 14 is provided inside, the two frustums 1 are fixedly connected at one end close to the second surface 12 to form an integrated structure, the frustum 1 is provided with a cavity 14 inside, and the first surface 11 and the second surface 12 are both provided with holes connected to the cavity 14, thereby forming a conical induction wall structure.

[0034] In this embodiment, the first surface 11 and the second surface 12 of the frustum 1 are square or rectangular, the cavity 14 is also a quadrangular pyramid-shaped cavity, and the holes passing through the first surface 11 and the second surface 12 are both square, so that the frustum 1 is a shell-like structure with uniform wall thickness, which facilitates subsequent uniform and stable deformation under pressure.

[0035] In this embodiment, the two frustums 1 are integrally formed by 3D printing. The material used in the printing process is AlSi10Mg metal powder, so that complex geometric shapes can be manufactured relatively easily. The AlSi10Mg alloy formed by SLM has a dense structure, fine grains, no shrinkage cavities and regional segregation, and has the strength of a cast AlSi10Mg alloy without any heat treatment, and can also ensure the uniformity of the structure.

[0036] Furthermore, the present invention discloses a lattice energy absorbing structure, comprising a plurality of energy absorbing elements as described in the above scheme, wherein vertically adjacent energy absorbing elements are fixedly connected together at one end close to the first surface 11 , and laterally adjacent energy absorbing elements are fixedly connected together near the middle of the second surface 12 .

[0037] In this embodiment, the energy absorbing elements are arranged in an array along three directions in space into a tetrahedral lattice structure, which is also formed by 3D printing. The number of columns in the three directions is set according to the actual application scenario.

[0038] In this embodiment, the number of cells in the vertical direction (the number of cones 1 in the vertical direction) is 26, the cells in the transverse and longitudinal directions are represented by n1, and the relationship between the total height h2 of the structure and the cell height h1 is: h2=26h1; the t value is 1.6mm, b1=b2=37.2mm, a1=a2=53.2mm, h2=400mm, and n1=4.

[0039] Figure 7 and 8 The dimensions of multi-cell tubes with the same size and material are: h3=h2=400mm, c1=c2=a1=a2=53.2mm, and the material thickness t is also 1.6mm.

[0040] The above two structures were subjected to axial quasi-static simulation analysis. A finite element model was established based on the material tensile test and the quasi-static compression test of the lattice structure. One end was fixed and the other end was compressed by the axial load of 10m / s on the rigid plate. The deformation mode of the tetrahedral lattice structure is as follows: Fig.10 As shown in Figure 2, the lattice structure is able to generate compact deformation patterns in a stable and controllable manner according to the prefabricated cone induction. Fig. 9As shown, its size is the same as that of the tetrahedral lattice structure. When subjected to axial compression load, the structural damage starts with a compact deformation mode and then transforms into a non-compact deformation mode, thus presenting a mixed mode, which has an adverse effect on the energy absorption efficiency. Fig.11 The axial compression crushing force curves of the multicellular tube structure and the tetrahedral lattice structure, where the solid line represents the crushing force curve of the honeycomb structure, and the dotted line represents the crushing force curve of the tetrahedral lattice structure. The multicellular tube structure has an initial peak load due to the generation of wrinkles, which reaches 759.38kN. In addition, the curve fluctuates greatly; the lattice structure has a stable deformation, and its crushing force has been maintained at the platform value, presenting a quasi-rectangular energy absorption curve within the effective displacement range.

[0041] In addition, by observing the structural compression crushing force curve, it is found that the effective displacement of the lattice structure is larger than that of the multi-cell tube structure under the condition of equal total height, which is conducive to energy absorption. The study found that the compression ratio of the tetrahedral lattice structure can be controlled by changing the cell size.

[0042] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An energy absorbing element, characterized in that: The invention comprises two frustums (1), each of the frustums (1) comprising a first surface (11), a second surface (12) and a side surface (13), the first surface (11) and the second surface (12) being arranged opposite to each other in the upper and lower parts, the side surface (13) being arranged between the first surface (11) and the second surface (12), the area of ​​the second surface (12) being larger than that of the first surface (11), the two frustums (1) being fixedly connected at one end of the second surface (12) to form an integrated structure, a cavity (14) being arranged inside the frustum (1), the first surface (11) and the second surface (12) being arranged with a hole connected to the cavity (14); the frustum (1) is a shell-like structure with uniform wall thickness.

2. The energy absorbing element according to claim 1, characterized in that: The frustum (1) is a prism structure in which the first surface (11) and the second surface (12) are parallel.

3. The energy absorbing element according to claim 2, characterized in that: The pyramid is a quadrangular pyramid, the first surface (11) and the second surface (12) of the quadrangular pyramid are square or rectangular, and the side surface (13) is a trapezoid.

4. The energy absorbing element according to claim 3, characterized in that: The first surface (11) and the second surface (12) of the frustum (1) are square, the side surface (13) is an isosceles trapezoid, and the holes penetrating the cavity (14) on the first surface (11) and the second surface (12) are both square holes.

5. The energy absorbing element according to claim 3, characterized in that: The cavity (14) is a frustum-shaped cavity that penetrates the first surface (11) and the second surface (12) at the upper and lower sides.

6. The energy absorbing element according to claim 3, characterized in that: The frustum (1) is a circular frustum whose first surface (11) and second surface (12) are parallel and circular.

7. The energy absorbing element according to any one of claims 1 to 6, characterized in that: The two frustums (1) are integrally formed by 3D printing.

8. A lattice energy absorption structure, characterized in that: It comprises a plurality of energy absorbing elements as claimed in any one of claims 1 to 5, wherein the vertically adjacent energy absorbing elements are fixedly connected together at one end close to the first surface (11), and the laterally adjacent energy absorbing elements are fixedly connected together near the middle of the second surface (12).

9. The lattice energy absorption structure according to claim 8, characterized in that: The energy absorbing elements are arranged in an array along three directions of space to form a quadrangular pyramid lattice structure.

10. The lattice energy absorption structure according to claim 9, characterized in that: The tetrahedral lattice structure is integrally formed by 3D printing.

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