A design method of a novel mechanical metamaterial database

Abstract

The application discloses a design method of a novel mechanical metamaterial database, the novel mechanical metamaterial database comprising a large number of novel lattice metamaterials; a minimum repeating unit of the novel lattice metamaterial is a building block; the method is as follows: the building block is formed into a representative unit through a symmetry operation of a graphic transformation, and the representative unit is periodically densely laid to form the novel lattice metamaterial; wherein the building block comprises three structural features, namely a boundary node, an internal node and a bar; a planar space occupied by the building block is a square; the building block has a total of four boundary nodes, which are located on four boundaries of the square; the building block has at least one internal node, which is distributed inside a quadrilateral region surrounded by the four boundary nodes of the building block; the position of the boundary node, the position of the internal node and the connection relationship between the nodes of the building block are determined based on a boundary node position rule, an internal node uniform distribution rule and a bar connectivity rule. The application can efficiently generate a large number of novel lattice metamaterials.

Description

Technical Field

[0001] The present invention relates to a design method for a novel mechanical metamaterial database. Background Art

[0002] Metamaterials are materials with artificially designed structures that exhibit extraordinary physical properties not found in naturally occurring materials. Lattice metamaterials, among them, are a type of truss-like porous structure composed of periodically repeating units with unusual mechanical properties. These structures, composed of periodic patterns or geometric networks based on the transformation of building block patterns, have attracted significant engineering attention due to their design flexibility and unique properties. Building blocks are the smallest repeating units of lattice metamaterials, and their mechanical properties depend on the structural form and arrangement and connection of the building blocks. This design flexibility of building blocks provides lattice metamaterials with a broad range of structural design possibilities, enabling them to achieve extraordinary properties such as high stiffness and a negative Poisson's ratio. Stiffness refers to the ability of a lattice metamaterial to resist elastic deformation under load and is a measure of the ease with which a structure can undergo elastic deformation. High stiffness is crucial for engineering applications such as ensuring gear meshing and machine tool machining accuracy. Stiffness is typically measured by the elastic modulus. Lattice metamaterials with high elastic modulus achieve lightweight while maintaining high stiffness, thus possessing high application value. The Poisson's ratio is the ratio of the lateral normal strain to the axial normal strain of a lattice metamaterial when it is subjected to unidirectional tension or compression. It is an elastic constant that reflects the lateral deformation of the lattice metamaterial. Most common engineering materials, such as metals, ceramics, and polymers, only have positive Poisson's ratios. However, negative Poisson's ratio materials with functions such as energy absorption and buffering and deformation control are very rare. When impacted, negative Poisson's ratio metamaterials can gather at the impact point to avoid catastrophic collapse and resist deformation. Therefore, they can be used to manufacture special vehicle tires, sports protective equipment, safety helmets and other engineering equipment. In addition, negative Poisson's ratio metamaterials have tensile and expansion properties consistent with skin and can be used to develop wearable devices such as flexible skin.

[0003] Existing design methods for lattice metamaterials primarily involve inspired design. This approach draws heavily from crystal, molecular, and biological structures, as well as combinatorial designs based on these structures. However, because it relies on the designer's experience and intuition, inspired design can only produce a limited number of lattice metamaterials and requires extensive repetitive calculations and verification. Consequently, this design strategy leaves a vast unexplored structural space.

[0004] Therefore, in the absence of expert knowledge and design guidelines, and the lack of design methods to efficiently generate a large number of new mechanical metamaterials, the structural design of new mechanical metamaterials remains extremely challenging and there is a huge gap. Summary of the Invention

[0005] The purpose of this application is to provide a design method for a novel mechanical metamaterial database, which can efficiently generate a large number of novel lattice metamaterials.

[0006] The technical solutions provided in this application are:

[0007] The technical solution adopted by the present invention to solve the above problems is:

[0008] In a first aspect, a method for designing a novel mechanical metamaterial database includes a large number of novel lattice metamaterials; the smallest repeating unit of the novel lattice metamaterial is a building block; the method comprises: forming representative units from the building blocks through symmetric operations of graphical transformations, and periodically tiling the representative units to form the novel lattice metamaterial;

[0009] The building block includes three structural features, namely boundary nodes, internal nodes and rods;

[0010] The planar space occupied by the building block is a side length of The building block has four boundary nodes, which are located on the four boundaries of the square; the building block has at least one internal node, which is distributed inside the quadrilateral area surrounded by the four boundary nodes of the building block;

[0011] The boundary node positions, internal node positions and the rod connection relationships between nodes of the building block are determined based on the boundary node position rules, the uniform distribution rules of the internal nodes and the rod connectivity rules.

[0012] In one possible implementation, there are 11 symmetry operation modes of graphic transformation, forming 11 representative units respectively; the 11 representative units are respectively recorded as p1, p2, p4, p4g, pm, pmm, pg, pgg, pmg, cm and cmm, respectively representing a simple translation transformation group, a double rotation transformation group, a quadruple rotation transformation group, a quadruple rotation sliding transformation group, a reflection transformation group, a double reflection transformation group, a sliding transformation group, a double sliding transformation group, a reflection sliding transformation group, a center reflection transformation group and a double center reflection transformation group.

[0013] In a possible implementation, the boundary node position rule is: boundary nodes in a single building block do not overlap, and boundary nodes between adjacent building blocks overlap;

[0014] The boundary node position rules include global boundary node position rules applicable to 11 representative units and boundary node position rules applicable to groups of different representative units;

[0015] Assume that in the building block, The position scale factor of the boundary nodes is ,This scaling coefficient is used to measure the position of the boundary node, which is equal to the ratio of the distance from the boundary node to the nearest vertex in the counterclockwise direction to the length of the building block edge;

[0016] The global boundary node position rule is: ,This rule ensures that the boundary nodes in the same building block do not overlap with each other;

[0017] The boundary node position rules in the group include a first rule and a second rule; the first rule is the connectivity of boundary nodes between adjacent building blocks within a representative unit; the second rule is the connectivity of boundary nodes between representative units when constructing a lattice metamaterial by planar tiling; the boundary node position rules in each group are expressed by the following formula:

[0018] p1: ;p2: ;p4: ;p4g: ;pm: ;pmm:none;pg: ;pgg: ;pmg: ; cm: ;cmm: ; The scale factors not mentioned are not restricted in the corresponding groups;

[0019] According to the boundary node position rules, the feasible boundary node coordinates are determined.

[0020] In a possible implementation, the uniform distribution rule of the internal nodes is: the internal nodes of the building block are uniformly distributed inside a quadrilateral area surrounded by four boundary nodes of the building block;

[0021] According to the uniform distribution rule of internal nodes, the feasible internal node coordinates are determined, including:

[0022] Generate feasible internal node coordinates through the intersection of bisectors within the quadrilateral area enclosed by the four boundary nodes of the building block;

[0023] A complete set of coordinate positions of internal nodes of different building blocks is generated by systematically traversing all feasible internal node coordinates, and the positions of each internal node do not overlap.

[0024] The coordinates of each set of feasible boundary nodes and internal nodes can form a node coordinate matrix. The dimension of the node coordinate matrix is ​​2 rows × number of nodes. The first row is the horizontal coordinate of the node, and the second row is the vertical coordinate of the node. The first four columns are boundary nodes. arrive The fifth to the last column are the coordinates of the internal nodes.

[0025] In one possible implementation, the entire adjacency matrix is ​​generated as a lookup table for member connections by traversing and folding the base n number system, where the value of n is , is the total number of nodes; the elements in the adjacency matrix are all natural numbers, and the non-zero element value indicates that there is a rod connection between the corresponding nodes. Different non-zero element values ​​represent different rod materials, and the element value of zero indicates that there is no rod connection between the corresponding nodes, that is, there is no connectivity between the corresponding nodes.

[0026] The member connectivity rule includes a first connectivity rule and a second connectivity rule;

[0027] The first connectivity rule requires that the boundary nodes must be ensured in the building blocks. and 、 and There is connectivity between them, that is, the boundary nodes and 、 and There is a continuous rod structure between them.

[0028] The second connectivity rule requires that internal nodes must be connected to at least two boundary nodes via rods to ensure their non-independence. Specifically, the corresponding row in the adjacency matrix must contain at least two non-zero elements. If an internal node's corresponding row in the adjacency matrix contains only one non-zero element, then the internal node is connected to only one other node. This independent internal node cannot transfer load, resulting in rod redundancy. Therefore, the second connectivity rule requires that internal nodes must have at least two non-zero elements in their corresponding row in the adjacency matrix. This second connectivity rule ensures the non-independence of internal nodes, guaranteeing the mechanical contribution of all rods.

[0029] The adjacency matrix that satisfies the first connectivity rule and the second connectivity rule is a feasible adjacency matrix.

[0030] In a possible implementation, the first connectivity rule is based on the p-th power of the adjacency matrix To judge, p ranges from 1 to the total number of rods in the building block; The value of represents the connectivity between nodes i and j. It means that there is connectivity between nodes i and j consisting of p rods. Indicates that there is no connectivity between nodes i and j.

[0031] Therefore, the first connectivity rule is that for any value of p, as long as there is , boundary nodes i and j are connected.

[0032] In a possible implementation, a set of feasible node coordinate matrices and a set of feasible adjacency matrices are generated, the set of feasible node coordinate matrices includes a plurality of feasible node coordinate matrices, each feasible node coordinate matrix including a set of coordinates of feasible boundary nodes and internal nodes; and the set of feasible adjacency matrices includes a plurality of feasible adjacency matrices.

[0033] Based on the set of feasible node coordinate matrices and the set of feasible adjacency matrices, a building block is generated.

[0034] The generated building block is verified to exclude three cases of rod intersection, rod overlap, and node on rod.

[0035] The verified building block is plane-tightly packed, that is, the design of a new mechanical metamaterial structure is implemented.

[0036] In a second aspect, the present application provides an electronic device, including a memory and a processor.

[0037] The memory is configured to store a computer program.

[0038] The processor is configured to invoke the computer program to perform the method as described above.

[0039] In a third aspect, the present application provides a computer-readable storage medium, the computer-readable storage medium stores a computer program, and the computer program is configured to cause an electronic device to implement the method as described above when the computer program is run on the electronic device.

[0040] In a fourth aspect, the present application provides a computer program product, including a computer program, and the computer program is configured to cause an electronic device to implement the method as described above when the computer program is run on the electronic device.

[0041] The specific implementation of the second to fourth aspects of the present application can refer to the implementation of the first aspect described above, and will not be repeated here.

[0042] Advantages:

[0043] Based on the design method of the present application, a large number of new lattice metamaterials can be quickly and efficiently constructed without relying on the experience and knowledge of designers, greatly reducing the repeated trial and error and the calculation cost in the design process. The generated large new mechanical metamaterial database will further promote the practical engineering application of lattice metamaterials, and can support the rapid design and search customization of various modulus and Poisson's ratio engineering requirements. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 The lattice metamaterial design method framework in the embodiments of the present application;

[0045] Figure 2 Symmetry operations for four graphical transformations and 11 planar crystal groups based on square building blocks;

[0046] Figure 3 This is the boundary node location rule in the embodiment of this application;

[0047] Figure 4 This is the uniform distribution rule of internal nodes in the embodiment of the present application;

[0048] Figure 5 The connectivity rules of the rod connections in the embodiment of the present application;

[0049] Figure 6 This is the design result of the lattice metamaterial structure in the embodiment of this application. DETAILED DESCRIPTION

[0050] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution of the present application will be further described in detail below in conjunction with the embodiments and drawings of the present application.

[0051] The present invention determines the boundary node positions, internal node positions, and rod connection relationships of the building blocks by designing boundary node position rules, uniform distribution rules for internal nodes, and rod connectivity rules. Planar tiling of the building blocks is then performed to achieve the design of a novel mechanical metamaterial structure. The method of the present invention enables the efficient design of a large number of lightweight lattice metamaterials with unique and novel structures. The lattice metamaterial structure generated by the present invention is a periodic two-dimensional truss-like porous structure formed by multiple rods fixedly connected at nodes, and its constituent materials are common engineering materials. The present invention can guide and expand the practical engineering applications of metamaterials and belongs to a functional material structure design method.

[0052] Specific embodiments according to the present application will be described below with reference to the accompanying drawings.

[0053] The present application relates to a design method for a novel mechanical metamaterial database, wherein the novel mechanical metamaterial database includes a large number of novel lattice metamaterials; the smallest repeating unit of the novel lattice metamaterial is a building block; the method comprises: forming representative units from the building blocks through symmetric operations of graphic transformations, and periodically tiling the representative units to form the novel lattice metamaterial;

[0054] The building block includes three structural features, namely boundary nodes, internal nodes and rods;

[0055] The planar space occupied by the building block is a side length of The building block has four boundary nodes, which are located on the four boundaries of the square; the building block has at least one internal node, which is distributed inside the quadrilateral area surrounded by the four boundary nodes of the building block;

[0056] The boundary node positions, internal node positions and the rod connection relationships between nodes of the building block are determined based on the boundary node position rules, the uniform distribution rules of the internal nodes and the rod connectivity rules.

[0057] The design object of the method of the present invention involves a truss-type porous structure composed of periodic repeating units, which is called a lattice metamaterial. As shown in part (a), the three design levels of building blocks, representative units (RVEs), and lattice metamaterials can be transformed into each other based on the symmetry and periodicity of graphic transformations. The planar space occupied by the building blocks is a The four boundary nodes are located on the four sides of the square. The boundary nodes have one degree of freedom along the edge and the boundary nodes are prohibited from overlapping. At least one internal node is located in the distribution area surrounded by the boundary nodes. The structure connecting the nodes is called a rod. The length of the rod is the distance between the nodes. The in-plane width and out-of-plane thickness of the rod section are respectively and , the constituent materials of the connecting rods between different nodes can be different.

[0058] like As shown in part (b), the design concept of the method of the present invention is based on the method of constructing a planar crystal group, which is a method of constructing a planar crystal group with a square pattern periodically covering the entire plane. In this application, the plane space occupied by the building block is a side length of The building blocks form representative units through the symmetry operation of graphic transformation, and the representative units are periodically paved to form metamaterials. The pattern corresponding to the representative units is periodically paved along the horizontal and vertical basis vectors in the plane to form a planar crystal group. Figure 1 As shown in part (c), the basic framework of the method described in the present invention is from basic structural features to building blocks, then to representative units (RVEs), and finally to lattice metamaterials.

[0059] Based on the three basic structural features of boundary nodes, internal nodes and rods, the present invention establishes boundary node position rules, uniform distribution rules and connectivity rules to generate building blocks. The present invention establishes boundary node position rules to determine the feasible boundary node coordinates in the building blocks. The design concept of boundary node position rules comes from 11 plane crystal groups based on squares. Planar crystal groups include all symmetry operations related to two-dimensional graphics, namely translation, reflection, rotation and sliding. As shown, the 11 planar crystal groups based on squares can be named P1, P2, P4, P4g, PM, PMM, PG, PGG, PMG, CM, and CMM, respectively, encompassing all combinations of symmetry operations for tiling a square in a plane. The fundamental design concept of this method is to embed building blocks within the square lattice of these planar crystal groups.

[0060] Accordingly, in the present application, the building blocks form representative units through the symmetry operations of graphic transformations. By adopting 11 symmetry operations of graphic transformations, 11 representative units can be formed, which are respectively recorded as p1, p2, p4, p4g, pm, pmm, pg, pgg, pmg, cm and cmm, respectively representing simple translation transformation group, double rotation transformation group, quadruple rotation transformation group, quadruple rotation sliding transformation group, reflection transformation group, double reflection transformation group, sliding transformation group, double sliding transformation group, reflection sliding transformation group, center reflection transformation group and double center reflection transformation group.

[0061] This application mathematically converts the symmetry operations of graph transformations into boundary node position rules to ensure the precise connection of boundary nodes between adjacent building blocks. The boundary node position rules can be divided into two aspects, including global boundary node position rules applicable to 11 representative units and boundary node position rules in groups applicable to different representative units; the boundary node position rules in groups include the first rule and the second rule. The first rule is the connectivity of boundary nodes between adjacent building blocks within a representative unit; the second rule is the connectivity of boundary nodes between representative units when constructing a lattice metamaterial by planar tiling. The square in part (a) represents a general building block with a direction, where points and vectors in homogeneous coordinates on a plane are represented as a three-dimensional vector ,in and is derived from Cartesian coordinates, is an extra dimension ( represents a point on the plane, represents a vector on a plane), the superscript T indicates the transpose. The position of the boundary node is expressed as The proportionality coefficient shown in part (a) Indicates that its boundary nodes and vertices 、 、 、 、 、 、 and The position vector of is expressed in homogeneous coordinate system as:

[0062]

[0063] where and is the edge length of the building block, and The position vector of a boundary node is The graph transformation is realized by computing the left dot product with the transformation matrix.

[0064] To prevent the coincidence of boundary nodes in the same building block, the global boundary node position rule is:

[0065]

[0066] where denotes the set. The mathematical description of the boundary node position rule is illustrated by the group p1, p4, pgg and pmm in (b)-(e) part of FIG. 5. The analysis of other groups is the same. As shown in (b) part of FIG. 5, the building block of the group p1 is consistent with the RVE, and the boundary nodes thereof only need to satisfy the first rule. The translation matrix corresponding to the horizontal and vertical direction plane dense paving base vector is:

[0067]

[0068] In the horizontal translation, the points and coincide, and the points and coincide, and the corresponding position vectors satisfy:

[0069]

[0070] In the vertical translation, the points and coincide, and the points and coincide, and the corresponding position vectors satisfy:

[0071]

[0072] The simultaneous equations and can obtain the boundary node position rule of the group p1:

[0073]

[0074] As shown in (c) part of FIG. 5, the building block of the group p4 is first translated with the vertex and then translated with the vertex​ A quadruple rotational symmetry is applied to construct the RVE, with the rotation angle of 90 degrees. The rotation transformation matrix of this process is:

[0075]

[0076] According to the first rule, the coincidence points in the rotation process include and , and and , and the corresponding position vectors satisfy:

[0077] .

[0078] According to the second rule, the corresponding position vectors of the node coincidence in the translation process are calculated as:

[0079] ,

[0080] In the formula, the translation matrix in the horizontal and vertical directions is:

[0081] .

[0082] The formulas and are combined, and the boundary node position rule of group p4 is:

[0083] .

[0084] As shown in part (d) of , the RVE of group pgg is formed by twice sliding transformation of the building block. The sliding transformation is a special basic transformation of reflection first and then translation. The midline of the building block is the reflection axis and the translation direction. The sliding transformation matrix in the horizontal and vertical directions is calculated as:

[0085] ,

[0086] The translation transformation matrix and the reflection transformation matrix in it are:

[0087]

[0088] The auxiliary transformation matrices and are used to handle the case where the sliding axis does not pass through the origin, which are represented as:

[0089] .

[0090] In the formula and Respectively represent the projection lengths of the distance between the sliding axis and the origin of the coordinate system in the horizontal and vertical directions. This shows the basic process of the sliding transformation. The point and the reflection axis are translated by the auxiliary transformation matrix to the intersection of the sliding axis and the origin, and then the reflection transformation is performed. The transformed point and the reflection axis are then moved back to their initial positions, and finally the translation transformation is performed along the reflection axis.

[0091] The above process requires points and 、 and 、 and 、 and coincide, the corresponding position vectors satisfy:

[0092] .

[0093] The boundary nodes of group pgg satisfy the formula The first rule represented by , automatically satisfies the second rule, so the boundary node position rule of group pgg is:

[0094]

[0095] In group PMM, boundary nodes naturally overlap during reflection and translation. As long as boundary nodes adhere to global rules, their positions are arbitrary. Therefore, group PMM imposes no additional constraints on boundary nodes. The complete boundary node position rules are shown in Table 1. Scaling factors not mentioned in the table are not restricted within the corresponding group. This completes the construction of boundary nodes using the method described in the present invention.

[0096]

[0097] The present invention establishes a uniform distribution rule to determine the feasible internal node coordinate positions in the building block. As shown in part (a), the white rectangle surrounded by dotted lines represents a building block. The boundary nodes on the four sides are marked as arrive .quadrilateral The enclosed area is called the distribution area, and the internal nodes are distributed within the distribution area. Part (b) shows equidistant points on the edge of the distribution area. In part (c), equidistant lines are drawn by connecting the equidistant points on these opposite sides. The positions of the internal nodes are determined by the intersection of these equidistant lines. As shown in part (d), when the number of equal points is 3, there are 9 equal points in total, named ~ The complete set of coordinate positions of the internal nodes of different building blocks is generated by systematically traversing all feasible internal node coordinates, and the positions of the internal nodes cannot overlap. Part (e) is an example of a building block with two internal nodes.

[0098] For any The building blocks of the internal nodes, the coordinates of which are stored in the node collection together with the boundary nodes:

[0099]

[0100] The present invention establishes connectivity rules to determine all feasible rod connections in the building block. The connectivity between nodes is determined using an adjacency matrix. This matrix is ​​used as a lookup table to indicate whether there is a rod connection between nodes in corresponding rows and columns. The elements in the adjacency matrix are all natural numbers, where non-zero element values ​​indicate that there is a rod connection between nodes, different non-zero element values ​​indicate different rod materials, and an element value of zero indicates that there is no connectivity between nodes. The adjacency matrix is ​​a symmetric matrix and can be represented by an upper (or lower) triangular matrix that does not include the main diagonal. Since the elements are all natural numbers, all potential adjacency matrices are generated by traversing and folding the base n number system, where the value of n is , is the total number of boundary nodes and internal nodes. For example, for a building block with four boundary nodes, two internal nodes, and two materials, the ternary number corresponding to an adjacency matrix can be "001001022000202". As shown in part (a), the ternary number is segmented and collapsed to form an adjacency matrix, which is then combined with the node set to generate building blocks. The connectivity rules of this invention include two aspects: the first connectivity rule ensures that the generated building blocks have a continuous structure to transmit mechanical loads; the second connectivity rule ensures that all rods contribute to force transmission, meaning that there are no redundant rods. The connectivity rules can be determined independently of specific node coordinates.

[0101] The first connectivity rule requires that the boundary nodes must be ensured in the building blocks and 、 and There is a continuous rod structure between them. This rule is based on the p-th power of the adjacency matrix To determine, p ranges from 1 to the total number of members in the building block. The value of represents the connectivity between nodes i and j. It means that there is connectivity between nodes i and j consisting of p rods. Therefore, the first connectivity rule is that for any value of p, as long as there is , the boundary nodes i and are connected. Part (b) shows the adjacency matrix that satisfies the first connectivity rule in both the horizontal and vertical directions. Adjacency matrices that do not satisfy the first connectivity rule are excluded from the design process. The second connectivity rule requires the non-independence of internal nodes to ensure the mechanical contribution of all rods. If the corresponding row of the adjacency matrix for an internal node contains only one nonzero element, the internal node is connected to only one other node. This independent internal node cannot transfer loads, resulting in redundancy of the rod. Therefore, the corresponding row of the adjacency matrix for the internal node should contain at least two nonzero elements. Part (c) shows a dependent internal node and an independent internal node (highlighted by the dotted line). Adjacency matrices with independent internal nodes are excluded from the design.

[0102] At this point, according to the boundary node position rule, uniform distribution rule and connectivity rule, a feasible node coordinate matrix set and a feasible adjacency matrix set can be obtained. When combining the two sets to generate building blocks, it is necessary to exclude Part (d) shows three cases: crossed rods, overlapping rods, and nodes on the rods. By further embedding the building blocks into a planar crystal group and performing planar tiling, the design of new lattice metamaterials can be realized.

[0103] Experimental verification:

[0104] (1) Set the design parameters. In the experiment, four boundary nodes and one internal node are used, and the cross-sectional dimensions of the rod are , the size of the planar space square occupied by the building block is The five feasible locations for each boundary node are specified at five equally spaced points on one edge of the square. Representative elements used are p2, pm, pmm, and cm. Group p2 has 25 uniformly distributed internal node locations, while the remaining three groups have 9 uniformly distributed internal node locations. The members are made of a single material: acrylonitrile butadiene styrene (ABS) plastic.

[0105] (2) Generate new lattice metamaterials. Generate lattice metamaterials based on design parameters and design framework. The design results of group p2 are 91956, the design results of group pm are 161432, the design results of group pmm are 897094, and the design results of group cm are 181669. Most of the metamaterials are unprecedented new designs. Each group shows 10 design results, such as shown.

[0106] Manufacturability of novel lattice metamaterials. Four groups each selected a novel lattice metamaterial for sample fabrication. Samples were prepared using an Ultimaker S5 fused deposition modeling 3D printer, using red ABS plastic.

[0107] like As shown, the four red samples are all well formed, which can verify the manufacturability of the design results and the feasibility of the method described in the present invention.

[0108] An embodiment of the present application further provides an electronic device, comprising: a memory and a processor;

[0109] The memory is used to store computer programs;

[0110] The processor is configured to call the computer program to execute the method described above.

[0111] An embodiment of the present application further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program. When the computer program is executed on an electronic device, the electronic device implements the method described above.

[0112] An embodiment of the present application further provides a computer program product, including a computer program. When the computer program is run on an electronic device, the electronic device implements the method described above.

[0113] The embodiments of the present application also provide a system, an electronic device, a computer-readable storage medium, and a computer program product. The specific implementation methods can refer to the specific embodiments of the above methods and will not be repeated here.

[0114] Obviously, those skilled in the art should understand that the above-mentioned units or steps of the present application can be implemented using a general-purpose computing device. They can be concentrated on a single computing device or distributed across a network composed of multiple computing devices. Alternatively, they can be implemented using program codes executable by the computing device, so that they can be stored in a storage device and executed by the computing device, or they can be made into individual integrated circuit modules, or multiple modules or steps can be made into a single integrated circuit module for implementation. Thus, the present application is not limited to any specific combination of hardware and software.

[0115] The above description of the embodiments of the present application is only a partial embodiment of the present application, which is used to enable professionals in this field to implement or use the contents of the present application, and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A design method for a new mechanical metamaterial database, characterized by: The novel mechanical metamaterial database includes a large number of novel lattice metamaterials; the smallest repeating unit of the novel lattice metamaterial is a building block; the method comprises: forming representative units from the building blocks through symmetric operations of graphic transformation, and periodically tiling the representative units to form the novel lattice metamaterial; The building block includes three structural features, namely boundary nodes, internal nodes and rods; The planar space occupied by the building block is a side length of The building block has four boundary nodes, which are located on the four boundaries of the square; the building block has at least one internal node, which is distributed inside the quadrilateral area surrounded by the four boundary nodes of the building block; The boundary node positions, internal node positions and the rod connection relationships between nodes of the building blocks are determined based on the boundary node position rule, the uniform distribution rule of internal nodes and the rod connectivity rule; the boundary node position rule is that the boundary nodes in a single building block do not overlap, and the boundary nodes between adjacent building blocks overlap; the uniform distribution rule of internal nodes is that the internal nodes of the building block are evenly distributed within the quadrilateral area surrounded by the four boundary nodes of the building block; the rod connectivity rule includes the first connectivity rule and the second connectivity rule; the first connectivity rule requires that the boundary nodes must be ensured in the building block. and 、 and There is connectivity between them, 、 、 and are boundary nodes located sequentially on the four boundaries of the building block; the second connectivity rule requires that an internal node must be connected to at least two boundary nodes through rods to ensure the non-independence of the internal nodes.

2. The method according to claim 1, characterized in that There are 11 symmetry operation modes of graphic transformation, forming 11 representative units respectively; the 11 representative units are respectively recorded as p1, p2, p4, p4g, pm, pmm, pg, pgg, pmg, cm and cmm, which respectively represent simple translation transformation group, double rotation transformation group, quadruple rotation transformation group, quadruple rotation sliding transformation group, reflection transformation group, double reflection transformation group, sliding transformation group, double sliding transformation group, reflection sliding transformation group, center reflection transformation group and double center reflection transformation group.

3. The method according to claim 2, characterized in that The boundary node position rules include global boundary node position rules applicable to 11 representative units and boundary node position rules applicable to groups of different representative units; Assume that in the building block, The position scale factor of the boundary nodes is ,This scaling coefficient is used to measure the position of the boundary node, which is equal to the ratio of the distance from the boundary node to the nearest vertex in the counterclockwise direction to the length of the building block’s edge; The global boundary node position rule is: , used to ensure that the boundary nodes in the same building block do not overlap with each other; The boundary node position rules in the group include a first rule and a second rule; the first rule is the connectivity of boundary nodes between adjacent building blocks within a representative unit; the second rule is the connectivity of boundary nodes between representative units when constructing a lattice metamaterial by planar tiling; the boundary node position rules in each group are expressed by the following formula: p1: ;p2: ;p4: ;p4g: ;pm: ;pmm:none; pg: ;pgg: ;pmg: ; cm: ;cmm: ; The scale factors not mentioned are not restricted in the corresponding groups; According to the boundary node position rules, the feasible boundary node coordinates are determined.

4. The method according to claim 3, characterized in that According to the uniform distribution rule of internal nodes, the feasible internal node coordinates are determined, including: Generate feasible internal node coordinates through the intersection of bisectors within the quadrilateral area enclosed by the four boundary nodes of the building block; A complete set of coordinate positions of internal nodes of different building blocks is generated by systematically traversing all feasible internal node coordinates, and the positions of each internal node do not overlap.

5. The method according to claim 4, characterized in that The entire adjacency matrix is ​​generated as a lookup table for member connections by traversing and folding the base n number system, where the value of n is , is the total number of nodes; the elements in the adjacency matrix are all natural numbers, and the non-zero element value indicates that there is a rod connection between the corresponding nodes. Different non-zero element values ​​represent different rod materials, and the element value of zero indicates that there is no rod connection between the corresponding nodes. The adjacency matrix that satisfies the first connectivity rule and the second connectivity rule is a feasible adjacency matrix.

6. The method according to claim 5, characterized in that The first connectivity rule is based on the p-th power of the adjacency matrix To judge, p ranges from 1 to the total number of rods in the building block; The value of represents the connectivity between nodes i and j. It means that there is connectivity between nodes i and j consisting of p rods. Indicates that there is no connectivity between nodes i and j; The second connectivity rule is based on the fact that there should be at least two non-zero elements in the row corresponding to the internal node in the adjacency matrix.

7. The method according to claim 1, wherein Generating the building blocks includes: Generate a feasible node coordinate matrix set and a feasible adjacency matrix set, wherein the feasible node coordinate matrix set includes multiple feasible node coordinate matrices, each feasible node coordinate matrix includes a set of feasible boundary node and internal node coordinates; the feasible adjacency matrix set includes multiple feasible adjacency matrices; Generate building blocks based on a set of feasible node coordinate matrices and a set of feasible adjacency matrices; The generated building blocks are verified to exclude the following three situations: crossing of members, overlapping of members, and nodes on members.

8. An electronic device, characterized in that: include: memory and processor; The memory is used to store computer programs; The processor is configured to call the computer program to execute the method according to any one of claims 1 to 7.

9. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and when the computer program is executed on an electronic device, the electronic device implements the method according to any one of claims 1 to 7.

10. A computer program product comprising a computer program, characterized in that When the computer program is executed on an electronic device, the electronic device implements the method according to any one of claims 1 to 7.

Images