Aluminum-based energy-absorbing dot matrix metamaterial based on bionic design and preparation method of aluminum-based energy-absorbing dot matrix metamaterial

Abstract

The invention provides an aluminum-based energy-absorbing dot matrix metamaterial based on bionic design, which comprises a dot matrix structure, the dot matrix structure comprises dot matrix unit cells which are periodically and regularly arranged in a three-dimensional space and are connected with one another, each dot matrix unit cell comprises a central part and a plurality of connecting parts, each surface of the central part is connected with one connecting part, and the connecting parts are connected with the central part. Each connecting part comprises a plurality of cambered surfaces, the cambered surfaces are arranged around the bottom surface of the connecting part, and the side edges of every two adjacent cambered surfaces are connected to form a side edge of the connecting part; the bottom edge of the cambered surface is connected with the edge of the central part; the same edge of the central part is connected with the cambered surfaces of the two adjacent connecting parts, the distance between the two cambered surfaces changes along a preset rule from the edge of the central part to the direction far away from the central part, and the preset rule is gradually increased, gradually decreased or gradually increased and then gradually decreased. According to the aluminum-based energy-absorbing dot matrix metamaterial based on bionic design, the problems that the bearing capacity of an existing SC dot matrix structure is reduced, and 3D printing complexity and cost are increased are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloys, and in particular to an aluminum-based energy-absorbing lattice metamaterial based on bionic design and a preparation method thereof. Background Art

[0002] Aluminum alloy lattice mechanical metamaterials are a new type of material with unique microstructure and macroscopic properties. They are usually composed of regularly arranged lattice structures and have the characteristics of corrosion resistance, high strength, light weight, and strong energy absorption, making them an ideal choice for the aerospace and automotive manufacturing fields.

[0003] The specific performance of the aluminum alloy lattice structure mainly depends on its structure. The existing aluminum alloy lattice structure, such as Figure 1 The simple cubic (SC) lattice structure shown, Figure 2 It is a schematic diagram of the explosion structure of SC.

[0004] Figure 1 The simple cubic (SC) lattice structure shown still has the following problems: First, stress concentration is prone to occur at the central node of the SC lattice structure, which will accelerate the destruction of the central node, reduce the bearing capacity of the entire structure, and further reduce the energy absorption capacity of the structure; second, since the SC lattice structure has a cantilever beam, in order to successfully realize 3D printing, it is usually necessary to add support or rotate a certain angle, which increases the complexity and cost of 3D printing. Summary of the invention

[0005] In view of the problems of reduced bearing capacity of existing simple cubic (SC) lattice structures, increased complexity and cost of 3D printing, the present application provides an aluminum-based energy-absorbing lattice metamaterial based on bionic design and a preparation method thereof.

[0006] In a first aspect, the present invention provides an aluminum-based energy-absorbing lattice metamaterial based on bionic design, including a lattice structure, wherein the lattice structure includes lattice unit cells that are periodically arranged and interconnected in a three-dimensional space, wherein the lattice unit cells include a central portion and a plurality of connecting portions, wherein each surface of the central portion is connected to one of the connecting portions, wherein each of the connecting portions includes a plurality of arc surfaces, wherein the arc surfaces are arranged around the bottom surface of the connecting portion, and the side edges of each two adjacent arc surfaces are connected to form a side edge of the connecting portion; and the bottom edge of the arc surface is connected to the edge of the central portion;

[0007] The same edge of the central part connects the arc surfaces of two adjacent connecting parts, and the distance between the two arc surfaces changes along a preset rule from the edge of the central part to the direction away from the central part, and the preset rule is gradually increasing, gradually decreasing, or first gradually increasing and then gradually decreasing.

[0008] Preferably, the bottom surface of the connecting portion is connected to the central portion, the top surface of the connecting portion is away from the central portion, and the area of ​​the top surface of the connecting portion is smaller than the area of ​​the bottom surface of the connecting portion.

[0009] Preferably, the central portion is a cubic structure, the bottom surface of the connecting portion is a square structure, and the bottom surface of the connecting portion coincides with one of the side surfaces of the central portion.

[0010] Preferably, the central portion includes a plurality of side surfaces and a plurality of first holes, wherein the first holes are arranged at the centers of the side surfaces, and the first holes extend from the side surfaces of the central portion toward the center of the central portion.

[0011] Preferably, the connecting portion comprises a second hole, the second hole is arranged on the bottom surface of the connecting portion, and the second hole extends from the bottom surface of the connecting portion to the top surface of the connecting portion and passes through the top surface of the connecting portion.

[0012] Preferably, a projection of an edge of the second hole located on the bottom surface of the connecting portion in the direction of the central portion coincides with an edge of the first hole.

[0013] Preferably, a cross section of the second hole gradually decreases from the bottom surface of the connecting portion to the top surface of the connecting portion.

[0014] Preferably, the cross-sections of the first hole and the second hole are both polygonal, circular or elliptical.

[0015] Preferably, the cross section of the connecting portion is polygonal.

[0016] In a second aspect, the present application provides a method for preparing the aluminum-based energy-absorbing lattice metamaterial based on bionic design as described above, comprising the following steps: using Al-Mg-Si-Cu-Fe-Cr-Zr alloy as a raw material and using a laser powder bed melting process to prepare;

[0017] In the laser powder bed melting process, the slice layer thickness is 30 μm, the laser power is 330 W, the scanning speed is 600 mm / s, and the scanning interval is 100 μm.

[0018] The present application provides an aluminum-based energy-absorbing lattice metamaterial based on bionic design, including a lattice structure, the lattice structure including lattice cells that are periodically arranged and interconnected in a three-dimensional space, the lattice cell including a central portion and a plurality of connecting portions, the side surfaces of the connecting portion being formed by connecting a plurality of arc surfaces, each surface of the central portion being connected to a connecting portion, the same edge of the central portion connecting two of the arc surfaces, and the distance between the two arc surfaces changing along a preset rule from the edge of the central portion to a direction away from the central portion, the preset rule being gradually increasing, gradually decreasing, or first gradually increasing and then gradually decreasing; an arch-like structure can be formed between the arc surface of the connecting portion and the central portion, and when the lattice cell is subjected to a load, the arch structure effectively enhances the compression resistance of the lattice cell, and the stress distribution is more uniform; the inclination angle of the connecting portion (also called a cantilever beam) in the cell is controllable, which improves the printability of the lattice structure, reduces the complexity of 3D printing, and reduces the printing cost; by introducing the bionic arch design, the mechanical properties of the lattice structure are significantly improved, and the mechanical properties of the aluminum-based energy-absorbing lattice metamaterial based on bionic design are improved. The aluminum-based energy-absorbing lattice metamaterial based on bionic design provided in the present application solves the problems of reduced bearing capacity of the existing simple cubic (SC) lattice structure and increased complexity and cost of 3D printing. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of a SC lattice unit cell in the prior art;

[0020] Figure 2 Exploded diagram of SC lattice unit cell in the prior art;

[0021] Figure 3 Schematic diagram of a simple cubic (SC) lattice building block in the prior art;

[0022] Figure 4 Schematic diagram of the aluminum-based energy-absorbing lattice metamaterial-lattice unit cell based on bionic design of the present application;

[0023] Figure 5 The aluminum-based energy-absorbing lattice metamaterial based on biomimetic design of the present application - exploded diagram of the lattice unit cell;

[0024] Figure 6 A schematic diagram of the aluminum-based energy-absorbing lattice metamaterial-lattice structure based on bionic design of the present application;

[0025] Figure 7 Compression stress-strain curves of the lattice structure of Example 1 and the lattice structure of Comparative Example 1 along the Z direction;

[0026] Figure 8 Comparative Example 1: Cross-sectional diagram of Mises stress distribution of lattice unit cell along Z direction compression;

[0027] Fig. 9Example 1: Cross-sectional diagram of the Mises stress distribution of the lattice unit cell along the Z direction;

[0028] 1. SC lattice unit cell; 10. end rod; 100. central node; 101. upper end rod; 102. rear end rod; 103. right end rod; 104. lower end rod; 105. front end rod; 106. left end rod;

[0029] 2. Lattice unit cell; 20. Connecting part; 200. Central part; 201. Upper connecting part; 202. Rear connecting part; 203. Right connecting part; 204. Lower connecting part; 205. Front connecting part; 206. Left connecting part. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0031] In order to illustrate the technical solution of the present invention, specific embodiments are provided below for illustration.

[0032] like Figure 4-6 As shown, the present application provides an aluminum-based energy-absorbing lattice metamaterial based on bionic design, including a lattice structure, wherein the lattice structure includes a lattice unit cell 2 that is periodically arranged and interconnected in a three-dimensional space, wherein the lattice unit cell 2 includes a central portion 200 and a plurality of connecting portions 20, wherein each surface of the central portion 200 is connected to a connecting portion 20, wherein each connecting portion 20 includes a plurality of arc surfaces, wherein the arc surfaces are arranged around the bottom surface of the connecting portion 20, and the side edges of each two adjacent arc surfaces are connected to form a side edge of the connecting portion 20; the bottom edge of the arc surface is connected to the edge of the central portion 200; the same edge of the central portion 200 connects the arc surfaces of two adjacent connecting portions 20, and the distance between the two arc surfaces from the edge of the central portion 200 to the direction away from the central portion 200 follows a preset rule, wherein the preset rule is gradually increasing, gradually decreasing, or first gradually increasing and then gradually decreasing.

[0033] Specifically, Figure 6 As shown, in the lattice structure, multiple lattice unit cells 2 in the x-axis direction are arranged according to a periodic rule, and two connected lattice unit cells 2 are connected to each other through a connecting portion 20, multiple lattice unit cells 2 in the y-axis direction are arranged according to a periodic rule, and two connected lattice unit cells 2 are connected to each other through a connecting portion 20, and multiple lattice unit cells 2 in the z-axis direction are arranged according to a periodic rule, and two connected lattice unit cells 2 are connected to each other through a connecting portion 20.

[0034] like Figure 4-5As shown, the lattice unit cell 2 includes a central part 200 and a plurality of connecting parts 20. The central part 200 includes a plurality of faces, each of which is connected to a connecting part 20. The connecting part 20 includes a bottom face, a top face and a side face. The bottom face of the connecting part 20 is connected to the central part 200. The side face of the connecting part 20 includes a plurality of arc faces, which are arranged around the bottom face of the connecting part 20. The side edges of each two adjacent arc faces are connected to form the side edges of the connecting part 20. Each face of the central part 200 includes an edge. The bottom edge of the arc face is the edge of the bottom face of the connecting part 20. The bottom edge of the arc face is connected to the edge of the central part 200, that is, the bottom face of the connecting part 20 is connected to the face of the central part 200.

[0035] like Figure 4 As shown, the same edge of the central portion 200 is connected to two adjacent arc surfaces of the connecting portion 20, and the distance between the two arc surfaces gradually changes from the edge of the central portion 200 to the direction away from the central portion 200, as shown in FIG. Figure 4 As shown, the distance between the two arc surfaces gradually increases, that is, the two arc surfaces extend in a direction away from the central portion 200, and the two arc surfaces gradually move away from each other, and the distance between the two arc surfaces gradually increases.

[0036] The distance between the two arc surfaces follows a preset rule, which is gradually increasing, gradually decreasing, or first gradually increasing and then gradually decreasing. Figure 4 In the structure of the arc surface shown, the distance between the two arc surfaces gradually increases; if the arc surface is an arched structure, the distance between the two arc surfaces first gradually increases and then gradually decreases.

[0037] The aluminum-based energy-absorbing lattice metamaterial based on bionic design provided by the present application includes a lattice structure, the lattice structure includes a lattice unit cell 2 including a central part 200 and a plurality of connecting parts 20, the side of the connecting part 20 is formed by connecting a plurality of arc surfaces, each surface of the central part 200 is connected to a connecting part 20, the same edge of the central part 200 connects two of the arc surfaces, and the distance between the two arc surfaces changes along a preset rule from the edge of the central part 200 to the direction away from the central part 200, and the preset rule is gradually increasing, gradually decreasing, or first gradually changing. The arc surface of the connecting part 20 and the central part 200 can form an arch-like structure. When the lattice unit cell 2 is under load, the arch structure effectively enhances the compression resistance of the lattice unit cell 2, and the stress distribution is more uniform. The inclination angle of the connecting part 20 (also called cantilever beam) in the unit cell is controllable, which improves the printability of the lattice structure, reduces the complexity of 3D printing, and reduces the printing cost. By introducing the bionic arch design, the mechanical properties of the lattice structure are significantly improved, and the mechanical properties of the aluminum-based energy-absorbing lattice metamaterial based on bionic design are improved. The aluminum-based energy-absorbing lattice metamaterial based on bionic design provided in the present application solves the problems of reduced bearing capacity of the existing simple cubic (SC) lattice structure and increased complexity and cost of 3D printing.

[0038] In some preferred embodiments, one end of the arc surface extends from the edge of the center portion 200 in a direction away from the center portion 200; the same edge of the center portion 200 connects the arc surfaces of two adjacent connecting portions 20, and the distance between the two arc surfaces gradually increases from the edge of the center portion 200 in a direction away from the center portion 200.

[0039] like Figure 4 As shown, in the unit cell, each edge of the central portion 200 is connected to two curved surfaces, and the distance between the two curved surfaces gradually increases from the edge of the central portion 200 to the direction away from the central portion 200, thereby facilitating the curved surface of the connecting portion 20 and the central portion 200 to form an arch structure, effectively enhancing the compression resistance of the lattice unit cell 2, making the stress distribution more uniform, significantly improving the mechanical properties of the lattice structure, and improving the mechanical properties of the aluminum-based energy-absorbing lattice metamaterial based on bionic design.

[0040] In some embodiments, the bottom surface of the connecting portion 20 is connected to the central portion 200 , the top surface of the connecting portion 20 is away from the central portion 200 , and the top surface area of ​​the connecting portion 20 is smaller than the bottom surface area of ​​the connecting portion 20 .

[0041] Specifically, Figure 4As shown, each surface of the central portion 200 is connected to a connecting portion 20, the bottom surface of the connecting portion 20 is connected to one of the surfaces of the central portion 200, the top surface of the connecting portion 20 is away from the central portion 200, and the top surface area of ​​the connecting portion 20 is smaller than the bottom surface area of ​​the connecting portion 20, which helps the connecting portion 20 and the central portion 200 to form an arch structure, and the stress distribution of the lattice structure is more uniform, thereby improving the mechanical properties of the lattice structure and the mechanical properties of the aluminum-based energy-absorbing lattice metamaterial based on bionic design.

[0042] In some embodiments, the central portion 200 is a cubic structure, the bottom surface of the connecting portion 20 is a square structure, and the bottom surface of the connecting portion 20 coincides with one of the side surfaces of the central portion 200 .

[0043] like Figure 4 , 5 As shown, the central portion 200 is a cube, each face of the central portion 200 is a square or a rectangle, each face of the central portion 200 is connected to the connecting portion 20, and the bottom surface of the connecting portion 20 is connected to the central portion 200. Then the corresponding bottom surface of the connecting portion 20 should also be the same shape as the side surface of the central portion 200, so the bottom surface of the connecting portion 20 is a square or rectangular structure.

[0044] The bottom surface of the connecting portion 20 overlaps with one of the side surfaces of the central portion 200. Specifically, if the central portion 200 is a cubic structure having six side surfaces, each side surface is connected to a connecting portion 20, and the side surface connected to the bottom surface of the connecting portion 20 is completely covered by the bottom surface of the connecting portion 20, and the edges of the bottom surface of the connecting portion 20 completely overlap with the edges of the corresponding side surfaces of the central portion 200 to which it is connected.

[0045] The bottom surface of the connecting portion 20 coincides with one of the side surfaces of the central portion 200. The connecting portion 20 and the central portion 200 together constitute a space frame, providing a three-dimensional support network for the lattice structure. When subjected to external forces, the load can be effectively transferred in the structure, stress can be dispersed, and the mechanical properties of the lattice structure can be improved, thereby improving the mechanical properties of the aluminum-based energy-absorbing lattice metamaterial based on bionic design.

[0046] It can be understood that the lattice type of the lattice structure of the aluminum-based energy-absorbing lattice metamaterial based on bionic design provided in the present application is a simple cube, so the central part 200 is a cube structure. If it is used for other types of lattice types, such as the lattice type is rhombus, the structure of the central part 200 is also changed accordingly.

[0047] In some embodiments, the cross section of the connecting portion 20 is a polygon.

[0048] Specifically, the cross section of the connecting portion 20 is a polygon, ensuring that each edge is connected to two arc surfaces, and no matter which direction the lattice unit cell 2 is subjected to force, there is support from the arch structure, which enhances the compressive strength of the lattice unit cell 2 and makes the stress distribution more uniform. The polygon is n-deformed, n is greater than or equal to 3; for example, the polygon includes a quadrilateral, a pentagon, a hexagon, an octagon, etc.

[0049] Further preferably, the cross section of the connecting portion 20 is a quadrilateral.

[0050] like Figure 4 , 5 As shown, the central portion 200 is a cubic structure, and the cross-section of the connecting portion 20 corresponds to a quadrilateral structure, which has a simple structure and is easy to prepare. It can also improve the mechanical properties of the lattice unit cell 2, thereby improving the mechanical properties of the aluminum-based energy-absorbing lattice metamaterial based on bionic design.

[0051] In some embodiments, the central portion 200 includes a plurality of side surfaces and a plurality of first holes, wherein the first holes are disposed at the centers of the side surfaces, and the first holes extend from the side surfaces of the central portion 200 to the center of the central portion 200 .

[0052] Specifically, Figure 5 As shown, the structure of the central part 200 is a cubic structure, including six sides, each side is composed of four edges, the four edges are connected end to end, and each side is provided with a first hole, which passes through the side and extends to the center of the central part 200.

[0053] The existing simple cube can be solid or in frame form. The lattice structure of the aluminum-based energy-absorbing lattice metamaterial based on bionic design provided in this application, in which the central part 200 is in frame form and has no filling material, can reduce weight and has good heat transfer or electrical transfer performance, and can be used in aerospace, mechanical engineering and other fields.

[0054] In some embodiments, one end of the first holes on each side of the central portion 200 intersects at the center of the central portion 200 .

[0055] Specifically, Figure 5 The exploded view of the lattice unit cell 2, the central part 200 is a cube, the cube has six sides, each side has a first hole, the first hole is square, the first hole passes through the side and extends to the center of the cube, the first holes of each side intersect at the center of the cube; the central part 200 obtained is a cube frame. A connection part 20 is connected to each side of the cube, and there are a total of six connection parts 20 in the lattice unit cell 2. Figure 5As shown, an upper connecting part 201 is connected to the upper side of the cube, a front connecting part 205 is connected to the front side of the cube, a right connecting part 203 is connected to the right side of the cube, a left connecting part 206 is connected to the left side of the cube, a lower connecting part 204 is connected to the lower side of the cube, and a rear connecting part 202 is connected to the rear side of the cube.

[0056] In some embodiments, the connecting portion 20 includes a second hole, which is disposed on the bottom surface of the connecting portion 20 , and the second hole extends from the bottom surface of the connecting portion 20 to the top surface of the connecting portion 20 and penetrates the top surface of the connecting portion 20 .

[0057] Specifically, Figure 5 As shown, the bottom surface of the connecting portion 20 is connected to one of the side surfaces of the central portion 200; a second hole is arranged on the bottom surface of the connecting portion 20, and the second hole extends from the bottom surface of the connecting portion 20 to the top surface of the connecting portion 20 and penetrates the top surface of the connecting portion 20. The connecting portion 20 is also in the form of a frame and has no filling material, which can also reduce weight and has good heat transfer or electrical transfer performance.

[0058] In some embodiments, the cross-sections of the first hole and the second hole are both polygonal, circular, or elliptical.

[0059] Specifically, the polygon is an n-gon, where n is greater than or equal to 3. For example, the polygon may be a quadrilateral, a pentagon, a hexagon, or the like.

[0060] In some preferred embodiments, the cross-section of the first hole and the second hole is a quadrilateral. More preferably, the cross-section of the first hole and the second hole is a square or a rectangle.

[0061] In some embodiments, the cross-sectional area of ​​the first hole is S1, the side area of ​​the central portion 200 is S2, and 1 / 2S2≤S1<S2.

[0062] The first hole has a larger area, which can reduce the weight of the central portion 200 .

[0063] In some embodiments, the cross-sectional area of ​​the second hole gradually decreases from the bottom surface of the connecting portion 20 to the top surface of the connecting portion 20 .

[0064] Because the bottom surface area of ​​the connecting portion 20 is larger than the top surface area of ​​the connecting portion 20 , the cross-sectional area of ​​the second hole of the connecting portion 20 gradually decreases from the bottom surface of the connecting portion 20 to the top surface of the connecting portion 20 .

[0065] In some embodiments, the area of ​​a side of the second hole facing the central portion 200 is defined as S3, the area of ​​the bottom surface of the connecting portion 20 is defined as S4, and 1 / 2S4≤S3<S4.

[0066] In some embodiments, the area of ​​a side of the second hole facing away from the central portion 200 is defined as S5, the area of ​​the top surface of the connecting portion 20 is defined as S6, and 1 / 2S6≤S5<S5.

[0067] Similarly, the area of ​​the second hole should be as large as possible to reduce the weight of the connecting portion 20 .

[0068] like Figure 6 As shown, this is the arrangement of the lattice structure. The size of the lattice unit cell 2 of the lattice structure is designed to be 6×6×6mm 3 In order to avoid the size effect of the lattice unit cell 2 and ensure the mechanical properties of the lattice structure, the number of lattice unit cells 2 in the lattice structure arranged along the three directions of x, y, and z is designed to be 5, thus forming an overall size of 30×30×30mm 3 Three-dimensional solid lattice blocks. Figure 6 This is only one arrangement of the lattice unit cells 2. It is understandable that the lattice unit cells 2 may also be arranged in other ways, and this application does not limit this.

[0069] exist Figure 6 In the figure, two adjacent lattice unit cells 2 are connected to each other through the top of the connecting portion 20, so that the two adjacent lattice unit cells 2 are connected.

[0070] In some embodiments, the projection of the edge of the second hole located on the bottom surface of the connecting portion 20 in the direction of the central portion 200 coincides with the edge of the first hole;

[0071] Specifically, Figure 5 As shown, the long side and the wide side of the second hole located on the bottom surface of the connecting part 20 coincide with the long side and the wide side of the first hole on the side surface of the central part 200 connected to the bottom surface of the connecting part 20, which facilitates the production of the lattice structure and reduces the difficulty of processing.

[0072] The aluminum-based energy-absorbing lattice metamaterial based on bionic design provided in the present application has a bionic arch structure that effectively enhances the compression resistance of the lattice unit cell 2 when the material is under load, can disperse stress, and make the stress distribution more uniform; the inclination angle of the cantilever beam of the lattice structure is controllable, which improves the printability of the lattice structure; by introducing the bionic arch design, the material significantly improves the mechanical properties of the aluminum-based energy-absorbing lattice metamaterial based on bionic design.

[0073] In a third aspect, the present application provides a method for preparing an aluminum-based energy-absorbing lattice metamaterial based on bionic design, comprising the following steps: using Al-Mg-Si-Cu-Fe-Cr-Zr alloy as a raw material and using a laser powder bed melting process to prepare the metamaterial;

[0074] In the laser powder bed melting process, the slice layer thickness is 30 μm, the laser power is 330 W, the scanning speed is 600 mm / s, and the scanning interval is 100 μm.

[0075] Specifically, Al-Mg-Si-Cu-Fe-Cr-Zr alloy is used as raw material and laser powder bed melting technology is used to construct a three-dimensional lattice structure to prepare an aluminum-based energy-absorbing lattice metamaterial based on bionic design.

[0076] In the laser powder bed melting process, Al-Mg-Si-Cu-Fe-Cr-Zr alloy powder particles are used as raw materials, the slice layer thickness is 30μm, the laser power is 330W, the scanning speed is 600mm / s, the scanning interval is set to 100μm, and the slice layer is scanned according to the predetermined path.

[0077] The present application provides a method for preparing an aluminum-based energy-absorbing lattice metamaterial, which has a simple preparation process and low cost.

[0078] The present invention is further described below by way of examples.

[0079] Example 1

[0080] This embodiment provides an aluminum-based energy-absorbing lattice metamaterial based on bionic design and a preparation method thereof.

[0081] The preparation method of aluminum-based energy-absorbing lattice metamaterial based on bionic design includes the following steps:

[0082] The material selected is Al-Mg-Si-Cu-Fe-Cr-Zr alloy, and the preparation method is laser powder bed fusion (LPBF) technology. The LPBF preparation process parameters are selected as follows:

[0083] The slice thickness was 30 μm, the laser power was 330 W, the scanning speed was 600 mm / s, and the scanning interval was set to 100 μm.

[0084] The structure of the prepared lattice unit cell 2 is as follows Figure 4-6 As shown. The central part 200 is a cube, and the cube has six sides. Each side has a first hole, and the first hole is square. The first hole passes through the side and extends to the center of the cube. The first holes on each side intersect at the center of the cube. The central part 200 obtained is a cube frame. A connecting part 20 is connected to each side of the cube. In the lattice unit cell 2, there are a total of six connecting parts 20. As shown Figure 5As shown, an upper connecting part 201 is connected to the upper side of the cube, a front connecting part 205 is connected to the front side of the cube, a right connecting part 203 is connected to the right side of the cube, a left connecting part 206 is connected to the left side of the cube, a lower connecting part 204 is connected to the lower side of the cube, and a rear connecting part 202 is connected to the rear side of the cube.

[0085] The connecting portion 20 includes a bottom surface, a top surface and a side surface. The bottom surface of the connecting portion 20 completely overlaps with one of the side surfaces of the central portion 200. The top surface of the connecting portion 20 is away from the central portion 200. The side surface of the connecting portion 20 is arranged between the bottom surface and the top surface of the connecting portion 20. The side surface of the connecting portion 20 is arranged by a plurality of arc surfaces surrounding the bottom surface of the connecting portion 20. The side edges of each two adjacent arc surfaces are connected to form the side edges of the connecting portion 20. The bottom edge of the arc surface is connected to the edge of the central portion 200; the same edge of the central portion 200 connects the arc surfaces of two adjacent connecting portions 20. From the edge of the central portion 200 to the direction away from the central portion 200, the distance between the two arc surfaces follows a preset rule, and the preset rule is gradually increased.

[0086] The bottom surface of the connecting portion 20 is provided with a second hole, and the second hole extends from the bottom surface of the connecting portion 20 to the top surface of the connecting portion 20 and penetrates the top surface of the connecting portion 20. The connecting portion 20 is also in the form of a frame without any filling material. The bottom surface area of ​​the connecting portion 20 is larger than the top surface area of ​​the connecting portion 20, and the projection of the top surface of the connecting portion 20 on the bottom surface of the connecting portion 20 is located within the bottom surface of the connecting portion 20.

[0087] The size of the bionic arch lattice unit cell 2 is designed to be 6×6×6mm. 3 In order to avoid the size effect of the lattice unit cell 2 and ensure the mechanical properties of the lattice structure, the lattice unit cell 2 of the lattice structure is arranged along Figure 6 The number of the three directions of x-axis, y-axis and z-axis is designed to be 5, so as to form Figure 6 The overall dimensions shown are 30×30×30mm 3 Three-dimensional solid lattice blocks.

[0088] Comparative Example 1

[0089] Comparative Example 1 is an existing simple cubic (SC) lattice building block. Figure 2 As shown, it is an exploded view of the existing SC lattice unit cell 1 structure, each face of the central node 100 is connected to an end rod 10, the end rod 10 is a cylinder, the circular bottom of the cylinder is connected to the side of the central node 100, and a third hole is arranged at the center of the end rod 10, the third hole passes through the cylinder, and the third hole extends to the body center of the central node 100, and the third holes of each face of the central node 100 intersect at the body center of the central node 100.

[0090] like Figure 1 As shown, an upper end rod 101 is connected to the upper side of the central node 100, a front end rod 105 is connected to the front side of the central node 100, a right end rod 103 is connected to the right side of the central node 100, a left end rod 106 is connected to the left side of the central node 100, a lower end rod 104 is connected to the lower side of the central node 100, and a rear end rod 102 is connected to the rear side of the central node 100. Figure 3 It is a top-bottom isometric view of an existing simple cubic (SC) lattice structure block.

[0091] The simple cubic (SC) lattice structure of Comparative Example 1 is also prepared by laser powder bed fusion (LPBF) technology, and the material is Al-Mg-Si-Cu-Fe-Cr-Zr alloy. The LPBF preparation process parameters are selected as follows:

[0092] The slice thickness was 30 μm, the laser power was 330 W, the scanning speed was 600 mm / s, and the scanning interval was set to 100 μm.

[0093] The mechanical properties of the aluminum-based energy-absorbing lattice metamaterial based on biomimetic design prepared in Example 1 and the aluminum-based lattice metamaterial with a simple cubic (SC) lattice structure prepared in Comparative Example 1 were tested. The test results are shown in Table 1.

[0094] Figure 7 The compressive stress-strain curves of the lattice structure of the aluminum-based energy-absorbing lattice metamaterial based on bionic design prepared in Example 1 and the simple cubic (SC) lattice structure prepared in Comparative Example 1 in the Z direction.

[0095] Table 1

[0096] Group Compression strength / MPa Energy absorption / J Example 1 29.4 361.4 Comparative Example 1 23.2 221.1

[0097] It can be seen from Table 1 that the lattice structure of the aluminum-based energy-absorbing lattice metamaterial based on bionic design prepared in Example 1 has a 26.7% higher compression strength and a 63.5% higher energy absorption than the simple cubic (SC) lattice structure of Comparative Example 1, indicating that the aluminum-based energy-absorbing lattice metamaterial based on bionic design provided in the present application has an arched structure that effectively enhances the compression resistance of the lattice unit cell 2, improves the mechanical properties of the lattice structure, and improves the mechanical properties of the aluminum-based energy-absorbing lattice metamaterial based on bionic design.

[0098] Figure 8 This is a cross-sectional diagram of the compressed Mises stress distribution along the Z direction of the SC lattice unit cell 1 in the simple cubic (SC) lattice structure of comparison example 1. Fig. 9 The cross-sectional diagram of the Mises stress distribution along the Z direction of the lattice unit cell 2 in the lattice structure of the aluminum-based energy-absorbing lattice metamaterial based on bionic design prepared in Example 1. Figure 8, 9 By comparison, it can be seen that the stress distribution of the lattice unit cell 2 in Example 1 is more uniform, indicating that the arched structure of the lattice unit cell 2 makes the stress distribution of the lattice structure more uniform, and significantly improves the mechanical properties of the aluminum-based energy-absorbing lattice metamaterial based on bionic design provided by the present application.

[0099] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that the technical solutions described in the above embodiments can still be modified, or some of the technical features can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention.

Claims

1. An aluminum-based energy-absorbing lattice metamaterial based on bionic design, characterized in that: It comprises a lattice structure, the lattice structure comprises lattice unit cells which are regularly arranged and connected to each other in a three-dimensional space, the lattice unit cells comprise a central part and a plurality of connecting parts, each surface of the central part is connected to one of the connecting parts, each of the connecting parts comprises a plurality of arc surfaces, the arc surfaces are arranged around the bottom surface of the connecting part, the side edges of each two adjacent arc surfaces are connected to form the side edges of the connecting part; the bottom edges of the arc surfaces are connected to the edges of the central part; The same edge of the central part connects the arc surfaces of two adjacent connecting parts, and the distance between the two arc surfaces changes along a preset rule from the edge of the central part to the direction away from the central part, and the preset rule is gradually increasing, gradually decreasing, or first gradually increasing and then gradually decreasing.

2. The aluminum-based energy-absorbing lattice metamaterial based on bionic design according to claim 1, characterized in that: The bottom surface of the connecting portion is connected to the central portion, the top surface of the connecting portion is away from the central portion, and the area of ​​the top surface of the connecting portion is smaller than the area of ​​the bottom surface of the connecting portion.

3. The aluminum-based energy-absorbing lattice metamaterial based on bionic design according to claim 1, characterized in that: The central portion is a cubic structure, the bottom surface of the connecting portion is a square structure, and the bottom surface of the connecting portion coincides with one of the side surfaces of the central portion.

4. The aluminum-based energy-absorbing lattice metamaterial based on bionic design according to claim 1 or 3, characterized in that: The central portion includes a plurality of side surfaces and a plurality of first holes, wherein the first holes are arranged at the centers of the side surfaces, and the first holes extend from the side surfaces of the central portion toward the center of the central portion.

5. The aluminum-based energy-absorbing lattice metamaterial based on bionic design according to claim 4, characterized in that: The connecting portion includes a second hole, which is disposed on a bottom surface of the connecting portion. The second hole extends from the bottom surface of the connecting portion to a top surface of the connecting portion and penetrates through the top surface of the connecting portion.

6. The aluminum-based energy-absorbing lattice metamaterial based on bionic design according to claim 5, characterized in that: The projection of the edge of the second hole located on the bottom surface of the connecting portion in the direction of the central portion coincides with the edge of the first hole.

7. The aluminum-based energy-absorbing lattice metamaterial based on bionic design according to claim 5, characterized in that: A cross section of the second hole gradually decreases from the bottom surface of the connecting portion to the top surface of the connecting portion.

8. The aluminum-based energy-absorbing lattice metamaterial based on bionic design according to claim 6 or 7, characterized in that: The cross sections of the first hole and the second hole are both polygonal, circular or elliptical.

9. The aluminum-based energy-absorbing lattice metamaterial based on bionic design according to claim 1, characterized in that: The cross section of the connecting portion is polygonal.

10. A method for preparing the aluminum-based energy-absorbing lattice metamaterial based on bionic design according to any one of claims 1 to 9, characterized in that: The following steps are involved: It uses Al-Mg-Si-Cu-Fe-Cr-Zr alloy as raw material and is made using laser powder bed fusion process; In the laser powder bed melting process, the slice layer thickness is 30 μm, the laser power is 330 W, the scanning speed is 600 mm / s, and the scanning interval is 100 μm.

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