Impact-resistant energy-absorbing metamaterial with three-period extremely-small curved surface and preparation method of impact-resistant energy-absorbing metamaterial

Abstract

The invention provides a three-period extremely-small-curved-surface impact-resistant energy-absorbing metamaterial and a preparation method thereof, and belongs to the field of functional structure metamaterials. According to the invention, the topological structure is introduced to the three-period minimal curved surface, so that the energy absorption capability and the impact resistance of the three-period minimal curved surface are obviously improved; on the basis, topological structures with different characteristics and densities are assembled according to layer-by-layer gradient arrangement or staggered arrangement through a multi-level design to obtain a multi-level three-period minimum curved surface metamaterial structure, and a local buckling mode and an overall deformation mechanism can be regulated and controlled at the same time; multi-scale regulation and control of mechanical properties and multipath of an energy absorption mode are realized, and impact resistance and energy absorption performance better than those of a single topological layer are obtained. The hierarchical design strategy shows significant advantages in the field of impact resistance and energy absorption, is beneficial to realization of mechanical property regulation and control, meets more complex service conditions, and is suitable for construction of multifunctional metamaterials with excellent impact resistance and high energy absorption.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of functional structure metamaterial design, and particularly relates to a three-period minimal surface anti-impact energy-absorbing metamaterial and a preparation method thereof. BACKGROUND

[0002] Impact load exists widely in aerospace, transportation, equipment protection and other fields, and severe impact will cause great damage to devices, equipment and human life. Therefore, it is very important to develop high-efficiency anti-impact and energy-absorbing structural materials. Such structures often have low density, strong designability, good energy-absorbing effect and other characteristics. Compared with traditional anti-impact materials such as metal foam, rubber cushion or composite protective plate, anti-impact metamaterials exhibit significant structure-property coupling advantages. First, anti-impact metamaterials are usually constructed based on metamaterial cells, and their performance is mainly determined by the geometric configuration, rather than simply relying on the material itself, thereby realizing the performance control by structure. Second, metamaterials have excellent specific energy absorption, which helps to reduce the overall structure weight. Third, such structures have high designability and parameterization control ability, and the precise control of impact response behavior can be realized through topology optimization, multi-scale modeling and other methods.

[0003] Triply Periodic Minimal Surface (TPMS) has attracted extensive attention due to its continuous surface topology and zero mean curvature characteristics. TPMS metamaterials not only can effectively reduce stress concentration and improve mechanical stability, but also can realize parameterization design and additive manufacturing through precise mathematical expression, and have shown application potential in impact protection and other fields. However, existing researches are still mostly limited to single-scale or uniform-thickness TPMS design, and the energy absorption mode of such structures tends to be single, which is prone to local collapse and early densification, and is difficult to meet the comprehensive requirements of gradual energy dissipation, delayed densification and fatigue durability under complex service environments. SUMMARY

[0004] The purpose of this invention is to provide a three-period minimal surface impact-absorbing metamaterial and its preparation method. Through parametric modeling and high-precision additive manufacturing, the structural performance can be gradient-based and customized. By introducing a multi-level topological structure onto the continuous surface of the TPMS (Thin-Surface Massive Surface), both local buckling modes and overall deformation mechanisms can be simultaneously controlled. This enables multi-scale control of mechanical properties and multi-path energy absorption modes, overcoming the shortcomings of TPMS, such as early densification and insufficient energy dissipation efficiency at a single scale. The multi-level structure not only allows for rapid energy dissipation through local configurations in the early stages of impact but also extends the stress plateau through interlayer synergy in the later stages, improving overall energy absorption efficiency and structural stability. This hierarchical design strategy exhibits significant advantages in the field of impact-absorbing metamaterials, further developing the design potential of three-period minimal surfaces, fully utilizing the surface design space, and facilitating controllable mechanical properties at different levels to meet more complex service conditions. It is suitable for constructing multifunctional metamaterials with excellent impact resistance and high energy absorption, particularly applicable to the needs of high-performance impact-absorbing structures in aerospace, equipment protection, and advanced manufacturing fields.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0006] A three-period minimal surface impact-absorbing metamaterial includes a three-period minimal surface lattice structure, wherein the three-period minimal surface lattice structure includes three-period minimal surface basic cells arranged in a periodic array in three-dimensional space.

[0007] The three-period minimal surface fundamental cell includes a topology mapped thereon, the topology comprising a grid divided by dividing lines.

[0008] As a supplement to the above scheme, the segmented mesh of the topology is triangular in shape, with adjacent triangles sharing a common side and a common vertex.

[0009] As a supplement to the above scheme, the segmented mesh of the topology is hexagonal in shape, with adjacent hexagons sharing sides and vertices.

[0010] As a supplement to the above scheme, the three-period minimal surface lattice structure includes at least two layers of three-period minimal surface basic units in the first direction of three-dimensional space. The number of dividing grids of the three-period minimal surface basic units in adjacent layers is different, and the dividing grids in the first direction have the same trend of changing number.

[0011] As a supplement to the above scheme, the three-period minimal surface lattice structure includes at least two layers of three-period minimal surface basic units in the first direction of three-dimensional space, and the number of grid segments of the three-period minimal surface basic units in adjacent layers is the same.

[0012] As a supplement to the above scheme, the three-period minimal surface lattice structure includes three layers of three-period minimal surface basic units in the first direction of three-dimensional space, and the number of segmented grids on the first to third layers of three-period minimal surface basic units are 384, 576 and 864 respectively.

[0013] As a supplement to the above scheme, the three-period minimal surface lattice structure includes three layers of three-period minimal surface basic units in the first direction of three-dimensional space, and the number of dividing grids on the first to third layers of three-period minimal surface basic units are 216, 304 and 376 respectively.

[0014] As a supplement to the above scheme, the three-period minimal surface lattice structure includes at least two layers of three-period minimal surface basic units in the first direction of three-dimensional space. The shape and number of the dividing grids on two adjacent three-period minimal surface basic units in the same layer are different, and the shape and number of the dividing grids on the three-period minimal surface basic units at corresponding positions in different layers are different.

[0015] As a supplement to the above scheme, the three-period minimal surface lattice structure includes three layers of three-period minimal surface basic cells in the first direction of three-dimensional space. In the first layer, 384 triangular segmented grids and 216 hexagonal segmented grids are mapped on two adjacent three-period minimal surface basic cells, respectively. In the second layer, 488 triangular segmented grids and 304 hexagonal segmented grids are mapped on two adjacent three-period minimal surface basic cells, respectively. In the third layer, 576 triangular segmented grids and 376 hexagonal segmented grids are mapped on two adjacent three-period minimal surface basic cells, respectively. The shapes of the segmented grids on the three-period minimal surface basic cells at corresponding positions in adjacent layers are different.

[0016] A method for preparing a three-period minimal curved surface impact-absorbing metamaterial includes:

[0017] S1. Establish the basic unit cell of the three-period minimal surface based on the implicit function equation;

[0018] S2. Design the shape and number of the segmented mesh that make up the topology, and map the topology with different shapes and / or numbers of the segmented mesh onto the three-period minimal surface basic cell to obtain three-period minimal surface cells mapped with different topologies.

[0019] S3. Using parametric modeling, the three-period minimal surface cells mapped with different topological structures are extended into at least three in the three-dimensional direction to generate the corresponding three-period minimal surface lattice structure.

[0020] S4. Mechanical properties of each three-period minimal surface lattice structure are tested, and the relationship function between the density of the topology and the mechanical properties is fitted; the density of the topology is defined as the number of subdivided grids on a single three-period minimal surface fundamental cell.

[0021] S5. Based on the mechanical performance requirements of the metamaterial at different stages of service, the mechanical performance of the three-period minimal surface lattice structure is matched, and the shape and density of the topology are determined based on the relationship function. Thus, the three-period minimal surface cells mapped with different topologies are arranged in a hierarchical gradient or alternately to form a multi-level three-period minimal surface metamaterial structure, and the multi-level three-period minimal surface metamaterial is obtained by additive manufacturing.

[0022] Furthermore, in step S4, the relationship function between the density of the topology and its mechanical properties is constructed through the following process:

[0023] S4.1. Supports are provided at the lowest point and suspended parts of each three-period minimal surface lattice structure, and 3D printing is used to form them.

[0024] S4.2. Impact tests were conducted on each of the three-period minimal surface lattice structures after printing to obtain the stress-strain curves of each three-period minimal surface lattice.

[0025] S4.3 Calculate the impact strength, specific impact strength, specific energy absorption and energy absorption efficiency of each three-period minimal surface lattice structure based on the stress-strain curves.

[0026] S4.4. The impact strength, specific impact strength, specific energy absorption, and energy absorption efficiency of the three-period minimal surface lattice structures mapped with different topological shapes are respectively fitted with straight lines to obtain the function between the topological density and mechanical properties under different topological shapes.

[0027] The beneficial effects of this invention are:

[0028] (1) This invention improves the energy absorption capacity and impact resistance of the three-period minimal surface by introducing different topological features (such as triangular honeycomb, hexagonal honeycomb, etc.) on the TPMS basic surface; and realizes efficient and rapid design of the three-period minimal surface through parametric modeling.

[0029] (2) This invention employs a multi-level design, assembling TPMS surface basic cells with different topological features, thicknesses, or densities in a layered or interlayered manner to obtain a multi-level structure with progressive and alternating collapse. This results in a structure with superior impact resistance and energy absorption performance compared to a single topological layer. Compared to TPMS with a single topological layer, the multi-level structure not only utilizes local configurations to achieve rapid energy dissipation in the initial stage of impact but also extends the stress plateau through interlayer synergy in the later stages, improving overall energy absorption efficiency and structural stability. This hierarchical design strategy demonstrates significant advantages in the field of impact resistance and energy absorption.

[0030] (3) Compared with the traditional Gyroid type TPMS structure, when the multi-level topological TPMS lattice structure contains three layers of three-period minimal surface basic units, its specific energy absorption is increased to 65.4%, its energy absorption efficiency is increased to 53.8%, and its specific impact strength is increased to 37.0%. Attached Figure Description

[0031] Figure 1 This forms the overall design framework of the present invention.

[0032] Figure 2 This describes the process of generating a topological mesh for a three-period minimal surface.

[0033] Figure 3 To generate a single topological structure, three-period minimal surface lattice structure, (a) is the basic three-period minimal surface, (b) is the topological segmentation grid of the three-period minimal surface, (c) is the basic cell of the three-period minimal surface mapped with topological structure, and (d) is the single topological structure three-period minimal surface lattice structure.

[0034] Figure 4 For the design process of multi-level three-period minimal surface structures, based on the mechanical performance analysis of a three-period minimal surface lattice structure with a single topology, the structural design can be matched with the performance requirements to design a suitable multi-level three-period minimal surface metamaterial.

[0035] Figure 5 The embodiments are multi-level three-period minimal surface lattice structures; wherein (a) is a multi-level three-period minimal surface lattice structure with a triangular honeycomb topology, and (b) is a multi-level three-period minimal surface lattice structure with a hexagonal honeycomb topology.

[0036] Figure 6 The example shows a multi-level, three-period minimal surface lattice structure with alternating arrangement and the composition of each cell in each layer. Detailed Implementation

[0037] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0038] The three-period minimal surface impact-absorbing metamaterial of this embodiment includes a three-period minimal surface lattice structure, which includes three-period minimal surface basic cells arranged in a periodic array in three-dimensional space; a topological structure is mapped on the three-period minimal surface basic cells, which is a honeycomb structure composed of several grids divided by dividing lines, and after the topological structure is mapped onto the three-period minimal surface basic cells, several hollow grids are formed on its surface.

[0039] In one embodiment, the segmented mesh of the topology is triangular in shape, with adjacent triangles sharing a common side and a common vertex.

[0040] In one embodiment, the segmented grid of the topology is hexagonal in shape, with adjacent hexagons sharing sides and vertices.

[0041] As a preferred embodiment of the present invention, the three-period minimal surface lattice structure includes at least two layers of three-period minimal surface basic cells in a first direction of three-dimensional space. The number of dividing grids of the three-period minimal surface basic cells in adjacent layers is different, and the number of dividing grids in the same direction has the same trend of change.

[0042] As a supplement to the above technical solution, the first direction is any direction, such as in the vertical direction, it includes at least two layers of three-period minimal surface basic cells from top to bottom, and the number of segmented grids of each layer of three-period minimal surface basic cells from top to bottom increases or decreases sequentially.

[0043] As a preferred embodiment of the present invention, the three-period minimal surface lattice structure includes at least two layers of three-period minimal surface basic units in the first direction of three-dimensional space. The shape and number of the dividing grids on two adjacent three-period minimal surface basic units in the same layer are different, and the shape and number of the dividing grids on the three-period minimal surface basic units at corresponding positions in different layers are different.

[0044] like Figure 1As shown, this embodiment provides a design method for three-period minimal surface metamaterials, mainly comprising two stages: the first stage involves cell modeling using computer-aided design software based on the design parameters of the three-period minimal surface cells; the second stage involves the design and additive manufacturing of multi-level three-period minimal surface metamaterial structures based on mechanical performance requirements. This method mainly includes the following steps:

[0045] S1. Establish the fundamental unit cell of the three-period minimal surface based on the implicit function equation; the fundamental unit cell of the three-period minimal surface is of Gyroid type, and the implicit function equation is:

[0046]

[0047] in, , , , The characteristic size of a unit cell, It is a constant that controls the closure of the volume of the three-period minimal surface.

[0048] S2. Design the shape and number of segmented meshes that make up the topology, and map the topologies with different shapes and numbers of segmented meshes onto the three-period minimal surface fundamental cells constructed in S1, to obtain three-period minimal surface cells mapped with different topologies; such as Figure 2 As shown, the specific process is as follows:

[0049] S2.1 Design the topology, including a hexagonal honeycomb topology and a triangular honeycomb topology; the hexagonal honeycomb topology is a topology with hexagonal meshes, and the triangular honeycomb topology is a topology with triangular meshes. The density of both topologies is given, i.e., the number of meshes on a single three-period minimal surface fundamental cell; the specific process is as follows:

[0050] In terms of topology design, the triangular honeycomb topology, which is dominated by tensile deformation with higher stiffness, and the hexagonal honeycomb topology, which is dominated by bending deformation with better energy absorption, are selected.

[0051] According to the two-dimensional Maxwell stability criterion

[0052] M = a - 2b + 3

[0053] Where a is the number of rod elements and b is the number of nodes; when M≥0, the topology is dominated by tensile deformation, and when M<0, the topology is dominated by bending deformation.

[0054] Calculations show that the triangular honeycomb topology has M=0, indicating that it is dominated by tensile deformation; while the hexagonal honeycomb topology has M=-3<0, indicating that it is dominated by bending deformation.

[0055] The number of grid divisions in the topology can be controlled by adjusting the number of horizontal (U Divisions) and vertical (V Divisions) control points in the Rhino Grasshopper LunchBox Panels plugin.

[0056] S2.2. Based on the selected topology, the shape and number of mesh segments are divided. The Rhino GrasshopperShape3D plugin is used to map the topology mesh segments onto the three-period minimal surface fundamental cells constructed in S1. The specific process is as follows:

[0057] First, Rhino Grasshopper Shape3D ShapeSolver is used to perform a two-dimensional planar unfolding operation on the three-dimensional three-period minimal surface basic cell constructed by S1;

[0058] Next, the design boundaries are determined using Rhino Grasshopper Shape3D ShapeMap;

[0059] Finally, Rhino Grasshopper Shape3D MapToShape is used to map the topology designed in S2.1 onto the design boundary, completing the topology mesh segmentation.

[0060] S2.3. Based on the given structural rod size R, use the Rhino Pipe command to generate three-period minimal surface cells mapped with different topologies.

[0061] S3. Based on the three-period minimal surface cells mapped with different topological structures, a three-period minimal surface lattice structure with the corresponding topological structure is generated through parameterization operations; specifically...

[0062] like Figure 3 As shown, by using Rhino Grasshopper parametric modeling, each of the three-period minimal surface cells generated by S2 is expanded by three in the x, y, and z directions to generate the corresponding three-period minimal surface lattice structure. The lattice structure can better reflect the performance characteristics of the metamaterial structure compared to the cellular structure.

[0063] S4. The mechanical properties of each three-period minimal surface lattice structure obtained in S3 are tested, and the relationship function between the density of the topology and the mechanical properties is fitted; the specific process is as follows:

[0064] S4.1. Supports are provided at the lowest point and suspended parts of each three-period minimal surface lattice structure, and 3D printing is used to form them.

[0065] S4.2. Impact tests were conducted on each of the three-period minimal surface lattice structures after printing to obtain the stress-strain curves of each three-period minimal surface lattice.

[0066] S4.3. Based on the stress-strain curves obtained in S4.2, calculate the impact strength of each three-period minimal surface lattice structure. ), specific impact strength ( ), specific energy absorption ( ) and energy absorption efficiency ( The calculation formula is as follows:

[0067]

[0068] in, This represents the compressive stress experienced by the three-period minimal surface lattice structure. The strain occurring in the three-period minimal surface lattice structure; The strain representing the beginning of the stress plateau period;

[0069]

[0070]

[0071]

[0072] in, The compaction strain represents the three-period minimal surface lattice structure. The relative density of the three-period minimal surface lattice structure is calculated using the following formula:

[0073]

[0074] in, The mass of the three-period minimal surface lattice structure; The three-period minimal surface lattice structure occupies an equivalent cubic volume;

[0075] S4.4. Linear fitting is performed on the impact strength, specific impact strength, and specific energy absorption of all three-period minimal surface lattice structures mapped to the triangular honeycomb topology, and on the same line, linear fitting is performed on the impact strength, specific impact strength, and specific energy absorption of all three-period minimal surface lattice structures mapped to the hexagonal honeycomb topology. This establishes the topological density under the triangular and hexagonal honeycomb topologies, respectively. The relationship function between different mechanical properties:

[0076]

[0077]

[0078]

[0079] in, , , , , , These are the fitting coefficients. , These represent triangular cellular topology and hexagonal cellular topology, respectively. This represents the topological density, which is the number of subdivided grids on a single three-period minimal surface fundamental cell, and its value ranges from 100 to 900.

[0080] S5. Based on the mechanical performance service requirements, including the impact strength requirements and energy absorption requirements at each stage of service, the mechanical performance of the three-period minimal surface lattice structure is matched. Based on the relationship function between the density of the topology and the mechanical performance, the shape and number of the segmented grid of the topology are obtained. Thus, the three-period minimal surface cells mapped with different topologies are arranged in a hierarchical gradient or alternating manner to obtain a multi-level three-period minimal surface metamaterial that meets the service requirements.

[0081] The hierarchical gradient arrangement means that the number of segmented grids mapped on each layer of the three-period minimal surface lattice structure is different, and the number increases or decreases sequentially layer by layer.

[0082] The alternating arrangement results in different grid shapes mapped onto two adjacent three-period minimal surface lattice cells in the same layer that form the three-period minimal surface lattice structure, and different grid shapes mapped onto corresponding three-period minimal surface lattice cells in different layers.

[0083] The alternating arrangement can also result in different shapes and numbers of segmented grids mapped onto two adjacent three-period minimal surface lattice cells in the same layer that make up the three-period minimal surface lattice structure, and different shapes and numbers of segmented grids mapped onto the three-period minimal surface lattice cells at corresponding positions in different layers.

[0084] S6. The multi-level three-period minimal surface metamaterial in step S5 is formed and manufactured using additive manufacturing process.

[0085] The following section uses a multi-level three-period minimal surface metamaterial with high impact resistance as an example to introduce the manufacturing method of the three-period minimal surface impact-absorbing metamaterial provided by this invention.

[0086] First, following steps S1 to S2, generate three-period minimal surface cells mapped with triangular honeycomb topology, with a topology density of 384 to 864, and generate three-period minimal surface cells mapped with hexagonal honeycomb topology, with a topology density of 132 to 484.

[0087] Then, through parameterization operations, the three-period minimal surface cells mapped with different shapes and densities are extended by three in the x, y, and z directions respectively, generating the corresponding three-period minimal surface lattice structure.

[0088] Following step S4, each three-period minimal curved surface lattice structure was 3D printed. The substrate used for printing was Formlabs® Flexible 80A, with an elastic modulus of 4.17 MPa, an ultimate tensile strength of 3.49 MPa, and a fracture strain of 64.09%. The printing layer thickness was set to 0.05 mm. After printing, the samples were ultrasonically cleaned with anhydrous ethanol for 5 minutes, and then cured at 60°C for 10 minutes using a UV curing machine.

[0089] After printing, impact tests were conducted at loading speeds of 5 mm / s and 25 mm / s to analyze the impact performance of different three-period minimal surface lattice structures. The relationship between topological density and different mechanical properties was fitted for triangular and hexagonal honeycomb topologies. The fitting coefficients are shown in Table 1. TG-TPMS represents a Gyroid-type three-period minimal surface lattice structure with a triangular honeycomb topology, and HG-TPMS represents a Gyroid-type three-period minimal surface lattice structure with a hexagonal honeycomb topology.

[0090] Table 1

[0091]

[0092] Based on the actual impact load, if a lower impact strength is needed in the initial part of the material to reduce the impact load, and a higher energy absorption is needed in the subsequent part. Based on the above service conditions, the three-period minimal surface cells generated in step S2 are arranged layer by layer according to different gradient modes to establish a system as follows: Figure 5 (a) Figure 5 (b) There are four types of three-level tri-periodic minimal surface metamaterials. The first letter in the figure indicates the type of topology, where T represents a triangular honeycomb topology and H represents a hexagonal honeycomb topology; the second letter indicates the gradient mode, where L is the maximum gradient and S is the minimum gradient. The maximum gradient is relative to the minimum gradient. The density of the topology on the three-periodic minimal surface cell increases more significantly with each layer; the numbers represent the topology density.

[0093] Among them, the three layers of the TL metamaterial are composed of three-period minimal surface cells with triangular honeycomb topological structures and topological densities of 384, 576, and 864, respectively, from top to bottom; the three layers of the TS metamaterial are composed of three-period minimal surface cells with triangular honeycomb topological structures and topological densities of 488, 576, and 728, respectively, from top to bottom; the three layers of the HL metamaterial are composed of three-period minimal surface cells with hexagonal honeycomb topological structures and topological densities of 132, 304, and 484, respectively, from top to bottom; and the three layers of the HS metamaterial are composed of three-period minimal surface cells with hexagonal honeycomb topological structures and topological densities of 216, 304, and 376, respectively, from top to bottom.

[0094] Next, alternating three-period minimal surface cells mapped with different types and densities of topological structures yielded the impact-resistant energy-absorbing metamaterial T+H. In the first layer of metamaterial T+H, adjacent three-period minimal surface cells are mapped with triangular and hexagonal honeycomb topologies, respectively, with densities of 384 and 216. In the second layer, adjacent three-period minimal surface cells are mapped with triangular and hexagonal honeycomb topologies, respectively, with densities of 488 and 304. In the third layer, adjacent three-period minimal surface cells are mapped with triangular and hexagonal honeycomb topologies, respectively, with densities of 576 and 376. The shapes of the topologies on corresponding upper and lower three-period minimal surface cells in adjacent layers are different. The specific structure is as follows: Figure 6 As shown.

[0095] The traditional Gyroid-type three-period minimal surface basic unit cell is generated in step S1 and constructed into a traditional Gyroid-type three-period minimal surface metamaterial. Its relative density is controlled by adjusting the wall thickness. With a relative density similar to the five metamaterials mentioned above, the relevant mechanical properties are recorded in Table 2.

[0096] Table 2

[0097]

[0098] Table 2 shows that when the impact load velocity is 25 mm / s, the specific energy absorption of the TL, TS, HL, HS, and T+H metamaterials is improved by 59.6%, 31%, 56.1%, 63.2%, and 65.4% respectively compared to the traditional Gyroid-type three-period minimal surface metamaterials; the energy absorption efficiency is improved by 17.3%, 15.4%, 48.1%, 57.7%, and 53.8%; and the specific impact strength is improved by 37%, 15.1%, 6.2%, 3.7%, and 25.9%. Therefore, multi-level three-period minimal surface metamaterials can significantly improve impact energy absorption capacity.

[0099] Table 3 records the mechanical properties of three-period minimal surfaces with a single-density topology, where the letter T represents a triangular honeycomb topology, H represents a hexagonal honeycomb topology, and the numbers represent the densities of the corresponding topologies.

[0100] Table 3

[0101]

[0102] Comparisons between TL metamaterials and T384, T576, and T864 metamaterials revealed advantages in specific energy absorption, energy absorption efficiency, and specific impact strength, particularly in specific energy absorption and specific impact strength. Comparisons between TS metamaterials and T488, T576, and T728 metamaterials showed that the performance of TS metamaterials was essentially equivalent to that of metamaterials with a single-density topology. Therefore, for tri-periodic minimal surface metamaterials mapped with a triangular honeycomb topology, layer-by-layer gradient arrangement does not necessarily improve performance. Adjusting the gradient magnitude can control the performance variation of the metamaterial, with larger gradient changes yielding better performance improvements. Comparing HL metamaterials with H132, H304, and H484 metamaterials, and comparing HS metamaterials with H216, H304, and H376 metamaterials, it can be found that HL and HS metamaterials have better overall performance, with HS metamaterials outperforming HL metamaterials. This indicates that for tri-periodic minimal surface metamaterials mapped with a hexagonal honeycomb topology, layer-by-layer gradient arrangement can improve the overall performance of the material, and the magnitude of the gradient changes layer by layer can affect the performance; the smaller the gradient, the better the performance improvement. Therefore, different topological shapes combined with different gradient changes result in inconsistent material performance changes, and customized control of metamaterials can be achieved by designing multi-level topological structures.

[0103] In summary, the innovative metamaterial and its design method provided by this invention make great use of and develop the design space of the three-period minimal surface, improve the designability of the three-period minimal surface, and enhance its energy absorption capacity and impact resistance. Through parametric modeling, efficient and rapid design of the three-period minimal surface can be achieved. Combined with additive manufacturing technology, it enables rapid prototyping and manufacturing of complex multi-level three-period minimal surface metamaterial structures.

[0104] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope defined by the claims of the present invention.

Claims

1. A three-period minimal curved surface impact-resistant energy-absorbing metamaterial, characterized in that, Including three-period minimal surface lattice structures, The three-period minimal surface lattice structure includes three-period minimal surface basic cells arranged in a periodic array in three-dimensional space. The three-period minimal surface fundamental cell includes a topology mapped thereon, the topology comprising a grid divided by dividing lines.

2. The three-period minimal curved surface impact-absorbing metamaterial according to claim 1, characterized in that, The topological structure is divided into triangular grids, with adjacent triangles sharing a common side and a common vertex.

3. The three-period minimal curved surface impact-absorbing metamaterial according to claim 1, characterized in that, The topological structure is divided into hexagonal grids, with adjacent hexagons sharing a common edge and a common vertex.

4. A three-period minimal curved surface impact-absorbing metamaterial according to any one of claims 1 to 3, characterized in that, The three-period minimal surface lattice structure comprises at least two layers of three-period minimal surface basic units in a first direction of three-dimensional space. The number of dividing grids in adjacent layers of three-period minimal surface basic units is different, and the dividing grids in the first direction have the same trend of changing number.

5. The three-period minimal curved surface impact-absorbing metamaterial according to claim 4, characterized in that, The three-period minimal surface lattice structure comprises three layers of three-period minimal surface basic units in the first direction of three-dimensional space. The number of dividing grids on the first to third layers of three-period minimal surface basic units are 384, 576, and 864, respectively.

6. The three-period minimal curved surface impact-absorbing metamaterial according to claim 4, characterized in that, The three-period minimal surface lattice structure comprises three layers of three-period minimal surface basic units in the first direction of three-dimensional space. The number of dividing grids on the first to third layers of three-period minimal surface basic units are 216, 304, and 376, respectively.

7. The three-period minimal curved surface impact-absorbing metamaterial according to claim 1, characterized in that, The three-period minimal surface lattice structure includes at least two layers of three-period minimal surface basic units in the first direction of three-dimensional space. The shape and number of the dividing grids on two adjacent three-period minimal surface basic units in the same layer are different, and the shape and number of the dividing grids on the three-period minimal surface basic units at corresponding positions in different layers are different.

8. The three-period minimal curved surface impact-absorbing metamaterial according to claim 7, characterized in that, The described three-period minimal surface lattice structure comprises three layers of three-period minimal surface basic cells in a first direction of three-dimensional space. In the first layer, adjacent three-period minimal surface basic cells are mapped with 384 triangular segmented grids and 216 hexagonal segmented grids, respectively. In the second layer, adjacent three-period minimal surface basic cells are mapped with 488 triangular segmented grids and 304 hexagonal segmented grids, respectively. In the third layer, adjacent three-period minimal surface basic cells are mapped with 576 triangular segmented grids and 376 hexagonal segmented grids, respectively. The shapes of the segmented grids on the three-period minimal surface basic cells at corresponding positions in adjacent layers are different.

9. A method for preparing a three-period minimal curved surface impact-absorbing metamaterial as described in any one of claims 1 to 8, characterized in that, Includes the following steps: S1. Establish the basic unit cell of the three-period minimal surface based on the implicit function equation; S2. Design the shape and number of the segmented meshes that make up the topology, and map the topology with different shapes and / or numbers of segmented meshes onto the three-period minimal surface basic cells to obtain three-period minimal surface basic cells mapped with different topology; the number of segmented meshes on a single three-period minimal surface basic cell is defined as the density of the topology. S3. Using parametric modeling, the three-period minimal surface cells mapped with different topological structures are extended into at least three in the three-dimensional direction to generate the corresponding three-period minimal surface lattice structure. S4. Mechanical properties of each three-period minimal surface lattice structure are tested, and the relationship function between the density of the topology and the mechanical properties is fitted. S5. Based on the mechanical performance requirements of the metamaterial at different stages of service, the mechanical performance of the three-period minimal surface lattice structure is matched, and the shape and density of the topology are determined based on the relationship function. Thus, the three-period minimal surface cells mapped with different topologies are arranged in a hierarchical gradient or alternately to form a multi-level three-period minimal surface metamaterial structure, and the multi-level three-period minimal surface metamaterial is obtained by additive manufacturing.

10. The preparation method according to claim 9, characterized in that, In step S4, the relationship function between the density of the topology and its mechanical properties is constructed through the following process: S4.

1. Supports are provided at the lowest point and suspended parts of each three-period minimal surface lattice structure, and 3D printing is used to form them. S4.

2. Impact tests were conducted on each of the three-period minimal surface lattice structures after printing to obtain the stress-strain curves of each three-period minimal surface lattice. S4.3 Calculate the impact strength, specific impact strength, specific energy absorption and energy absorption efficiency of each three-period minimal surface lattice structure based on the stress-strain curves. S4.

4. The impact strength, specific impact strength, specific energy absorption, and energy absorption efficiency of the three-period minimal surface lattice structures mapped with different topological shapes are respectively fitted with straight lines to obtain the function between the topological density and mechanical properties under different topological shapes.

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