A three-dimensional structure configuration material and a screening method and a design method of a three-dimensional structure unit cell configuration

Abstract

The present application relates to a kind of three-dimensional structure configuration material and three-dimensional structure cell configuration screening method, design method, belong to application material field.Material is configured with the cell structure with geometric multiscale characteristics, cell structure is constructed using fractal dimension, layer number, thickness of each layer, duty cycle of each layer as common geometric characteristic parameter, the fractal dimension is used to quantitatively characterize the complexity of the configuration three-dimensional structure cell configuration, and the fractal dimension is obtained according to the overall calculation of specific three-dimensional structure cell configuration.The present application uses fractal dimension to quantitatively characterize the complexity of structure geometric characteristic, and establishes the mathematical model of fractal structure by selecting common geometric characteristic parameters such as structure thickness, duty cycle, to create a kind of composite material using structure mathematical description method.

Description

[0001] A method for screening and designing three-dimensional structural configuration materials and three-dimensional structural unit cell configurations. Technical Field

[0002] This invention relates to a class of multi-scale fractal structure materials and related design methods for three-dimensional unit cell configurations, belonging to the field of applied materials. Background Technology

[0003] Compared to Euclidean geometry with integer dimensions, fractal geometry uses fractional dimensions to represent disordered, complex, and singular objects, reflecting their irregularity and complexity. Fractal geometry possesses self-similarity, meaning that fractal systems can exhibit self-similarity simultaneously in morphology, information, and function, or only in one aspect. Therefore, self-similarity is not limited to precise and rigorous self-similarity but also includes approximate and statistical self-similarity, requiring only that a certain characteristic parameter of the object's local and overall morphology or property remains consistent. Considering that fractal geometry can study the geometric characteristics of nonlinear objects, fractal dimension can characterize the complexity of structural geometric features. This paper employs fractal geometry methods to mathematically describe lossy dielectric structures with three-dimensional configurations, establishing a method for representing and constructing the geometric features of fractal structures. Summary of the Invention

[0004] The technical problem solved by this invention is to overcome the problem of complex structural characterization in existing technologies and to provide a three-dimensional structural configuration material for parametric modeling of multi-scale three-dimensional structural unit cell configurations and to guide the design of new configurations.

[0005] The technical problem further addressed by this invention is to provide a method for screening and designing three-dimensional structural unit cell configurations.

[0006] The technical solution of the present invention is: a three-dimensional structural configuration material, wherein the material is composed of a single-cell structure with geometric multi-scale characteristics, and the single-cell structure is constructed using fractal dimension, number of layers, thickness of each layer, and duty cycle of each layer as common geometric feature parameters. The fractal dimension is used to quantitatively characterize the complexity of the three-dimensional structural single-cell configuration, and the fractal dimension is calculated based on the specific three-dimensional structural single-cell configuration.

[0007] Preferably, the fractal dimension is calculated in the following manner:

[0008] Construct a geometric model of a three-dimensional structural unit cell configuration, and use cubic meshes of different scales to contain the three-dimensional space occupied by the geometric model;

[0009] Calculate the number of cubic meshes containing objects, Nr;

[0010] right and In least squares regression analysis, the slope of the fitted line is the fractal dimension.

[0011] Where r is the side length of the cubic grid, and r decreases by a factor of 10 to cover at least 3 orders of magnitude.

[0012] Preferably, the unit cell structure with geometric multi-scale characteristics includes honeycomb configuration, stepped cone configuration, woodpile configuration, square frame configuration, and combined configuration; the honeycomb configuration is a multi-layered honeycomb gradient arrangement stacked from large to small; the stepped cone configuration is a multi-layered cube gradient arrangement stacked from large to small; the woodpile configuration is a multi-layered staggered arrangement of cuboids; the square frame configuration is a multi-layered cube gradient arrangement stacked from large to small; and the combined configuration is a multi-layered arrangement of cuboids and square frames.

[0013] A method for screening three-dimensional structural unit cell configurations, comprising:

[0014] The material with the smallest fractal dimension was selected from all the described three-dimensional structural configuration materials to complete the screening process, thus determining the configuration with the best electromagnetic loss performance.

[0015] A design method for a three-dimensional structural unit cell configuration includes:

[0016] A three-dimensional structural configuration material as described in claim 1 is initially selected as the current design three-dimensional structural unit cell configuration. Simulation experiments are conducted to determine whether the electromagnetic loss performance of the current three-dimensional structural unit cell configuration meets the application requirements. If it meets the application requirements, the currently determined three-dimensional structural unit cell configuration is the final configuration; otherwise, subsequent processing is carried out.

[0017] Determine the fractal dimension, number of layers, thickness of each layer, and duty cycle of each layer for the unit cell configuration of the three-dimensional structure;

[0018] Based on the principle that the smaller the fractal dimension, the better the electromagnetic loss performance, the configuration of the three-dimensional structure unit cell is changed by adjusting the thickness of each layer and the duty cycle of each layer until its electromagnetic loss performance meets the requirements.

[0019] Preferably, the three-dimensional structural unit cell configuration is a multi-layer honeycomb configuration.

[0020] Preferably, during the adjustment process, if the duty cycle of each layer remains unchanged, the thickness is adjusted according to the following rule:

[0021] When the total thickness of the structure changes, as the thickness of each individual layer increases, the frequency of the absorption peak shifts to a lower frequency band; the increase in the thickness of the outermost layer leads to a decrease in the corresponding reflection loss value and a narrowing of the frequency range of the peak point region; the increase in the thickness of the middle layer leads to a decrease in the corresponding reflection loss value and a widening of the frequency range of the peak point region.

[0022] Preferably, during the adjustment process, if the total thickness of the configuration remains unchanged, the adjustment is carried out according to the following rules:

[0023] By adjusting the thickness of the intermediate or surface layer, sacrificing some of the electromagnetic loss performance at the peak point (i.e., disregarding the positional change of the absorption peak frequency point), the frequency range of the region where the peak point is located is widened, thereby achieving the technical specifications of an effective absorption frequency band.

[0024] Preferably, during the adjustment process, if the configuration thickness remains unchanged, the duty cycle is adjusted according to the following rules:

[0025] The duty cycle of each layer represents the wall thickness of the honeycomb structure. By increasing the wall thickness of the surface layer, the effective absorption bandwidth can be covered in the low-frequency band; by reducing the wall thickness of the middle layer, the electromagnetic loss performance at the peak point can be enhanced.

[0026] A design method for a three-dimensional structural unit cell configuration includes:

[0027] Simulation experiments were conducted on the three-dimensional structural configuration material described in claim 1 as all three-dimensional structural unit cell configurations to be designed to determine their electromagnetic loss performance; and a statistical relationship between the fractal dimension and electromagnetic loss performance of each three-dimensional structural unit cell configuration was constructed.

[0028] Based on the current application environment, a three-dimensional structural unit cell configuration that meets the electromagnetic loss performance requirements is selected according to the statistical relationship; or, if the currently used three-dimensional structural unit cell configuration has been determined, it is determined whether the electromagnetic loss performance of the current three-dimensional structural unit cell configuration meets the application requirements. If it meets the application requirements, the currently determined three-dimensional structural unit cell configuration is the final configuration; otherwise, according to the principle that the smaller the fractal dimension, the better the electromagnetic loss performance, the three-dimensional structural unit cell configuration is changed by adjusting the thickness of each layer / duty cycle of each layer of the current configuration until its electromagnetic loss performance meets the requirements.

[0029] The beneficial effects of this invention compared to the prior art are as follows:

[0030] This invention uses fractal dimension to quantitatively characterize the complexity of structural geometric features. By selecting common geometric feature parameters such as structural thickness and duty cycle, a mathematical model of fractal structure is established, creating a universal mathematical description method for composite material structures that can achieve parameterized modeling of three-dimensional medium-type functional structures.

[0031] This invention can analyze the influence of common geometric characteristic parameters such as fractal dimension, thickness, and duty cycle on the mechanical properties of structures and design new structural forms.

[0032] This invention establishes a statistical mapping relationship between fractal dimension and absorption performance by determining the fractal dimension of different electromagnetic structures. The fractal dimension can be used to screen for optimal configuration designs that meet the impedance matching and attenuation characteristics of the structure for electromagnetic waves. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the honeycomb structure.

[0034] Figure 2 (a) Fractal dimension statistical model of the honeycomb structure; (b) Fractal dimension statistical model of configuration 1;

[0035] Figure 3 The cross-sectional grids of the honeycomb structure are shown in (a) section 1, (b) section 2, (c) section 3, and (d) section 4.

[0036] Figure 4 This is a schematic diagram of the stepped cone structure.

[0037] Figure 5 (a) Fractal dimension statistical model of configuration 2; (b) Characteristic profile of configuration 2;

[0038] Figure 6 The cross-sectional grids are for the stepped cone structure; (a) section 1, (b) section 2, (c) section 3, (d) section 4;

[0039] Figure 7 This is a schematic diagram of the configuration of a woodpile structure;

[0040] Figure 8 The fractal dimension statistical model of the wood stack structure; (a) fractal dimension statistical model of configuration 3; (b) characteristic profile of configuration 3;

[0041] Figure 9 The cross-sectional grids of the timber stack structure are: (a) Sections 1, 3, 5, 7, 9, 11, 13, 15, (b) Section 2, (c) Section 4, (d) Section 6, (e) Section 8, (f) Section 10, (g) Section 12, (h) Section 14.

[0042] Figure 10 This is a schematic diagram of the rectangular structure.

[0043] Figure 11 The fractal dimension statistical model of the box structure; (a) fractal dimension statistical model of configuration 4; (b) characteristic profile of configuration 4;

[0044] Figure 12The cross-sectional grids are for a rectangular structure; (a) Section 1, (b) Section 2, (c) Section 3, (d) Section 4;

[0045] Figure 13 This is a schematic diagram of the configuration of composite structure 1;

[0046] Figure 14 (a) Fractal dimension statistical model of configuration 1; (b) Fractal dimension statistical model of configuration 5;

[0047] Figure 15 The cross-sectional meshes for composite structure 1; (a) cross-section 1, (b) cross-section 2, (c) cross-section 3;

[0048] Figure 16 This is a schematic diagram of the configuration of combined structure 2;

[0049] Figure 17 (a) Fractal dimension statistical model of configuration 2; (b) Fractal dimension statistical model of configuration 6;

[0050] Figure 18 The cross-sectional meshes for composite structure 2; (a) section 1, (b) section 2, (c) section 3, (d) section 4, (e) section 5;

[0051] Figure 19 This is a schematic diagram of the configuration of composite structure 3;

[0052] Figure 20 (a) Fractal dimension statistical model of configuration 3; (b) Fractal dimension statistical model of configuration 7;

[0053] Figure 21 The cross-sectional meshes for composite structure 3 are shown in Figure 1, (a) Section 1, (b) Section 2, (c) Section 3, and (d) Section 4. Detailed Implementation

[0054] The following is in conjunction with the appendix Figure 1-21 The present invention will be described in detail below.

[0055] This invention provides a three-dimensional structural configuration material, which is composed of a single-cell structure with geometric multi-scale characteristics. The single-cell structure is constructed using fractal dimension, number of layers, thickness of each layer, and duty cycle of each layer as common geometric feature parameters. The fractal dimension is used to quantitatively characterize the complexity of the three-dimensional structural single-cell configuration, and the fractal dimension is calculated based on the specific three-dimensional structural single-cell configuration.

[0056] The aforementioned geometrically multi-scale characteristic unit cell structures include honeycomb configurations (such as...) Figure 1 As shown), stepped cone configuration ( Figure 4), woodpile configuration ( Figure 7 ), box configuration ( Figure 10 ), combined configuration 1 ( Figure 13 ), combined configuration 2 ( Figure 16 ), combined configuration 3 ( Figure 19 The honeycomb configuration consists of multiple layers of honeycomb gradient arrangement, stacked from largest to smallest; the stepped cone configuration consists of multiple layers of cube gradient arrangement, stacked from largest to smallest; the woodpile configuration consists of multiple layers of staggered cuboids; the square frame configuration consists of multiple layers of square frame gradient arrangement, stacked from largest to smallest; and the combined configuration consists of multiple layers of cuboids and square frames.

[0057] Fractal dimension is currently generally calculated using the box-counting dimension method for multi-scale structures. If a geometric object with a measured volume of V can be filled with spheres of radius r, then the required number of spheres is...

[0058]

[0059] Generalizing to the general case, for a volume A and a fractal dimension of... If a geometric object is to be measured using spheres of radius r, then the number of spheres required is _____.

[0060]

[0061] Here, C is the structural factor. Therefore, the fractal dimension is...

[0062]

[0063] This invention provides a preferred embodiment in which the fractal dimension is calculated in the following manner:

[0064] Construct a geometric model of a three-dimensional structural unit cell configuration, and use cubic meshes of different scales to contain the three-dimensional space occupied by the geometric model;

[0065] Calculate the number of cubic meshes containing objects, Nr;

[0066] right and In least squares regression analysis, the slope of the fitted line is the fractal dimension.

[0067] Where r is the side length of the cubic grid, and r decreases by a factor of 10 to cover at least 3 orders of magnitude.

[0068] From a design perspective, configurations with higher complexity have more structural dimensional parameters and a larger design space, allowing for the selection of optimal configurations to meet the impedance matching and attenuation requirements for electromagnetic waves. This invention studies the use of fractal dimension as a quantitative indicator of structural complexity, which can be used to select optimal configuration designs. Specifically, it provides a method for selecting three-dimensional structural unit cell configurations, including:

[0069] All current three-dimensional structural configuration materials are described in the above manner, and the material with the smallest fractal dimension is selected as the configuration with the best electromagnetic loss performance to complete the screening.

[0070] The present invention further provides a method for designing a three-dimensional structural unit cell configuration, comprising:

[0071] A three-dimensional structural configuration material was initially determined as the current design unit cell configuration for the three-dimensional structure, and simulation experiments were conducted to determine whether the electromagnetic loss performance of the current three-dimensional structural unit cell configuration met the application requirements. If it met the application requirements, the currently determined three-dimensional structural unit cell configuration was the final configuration; otherwise, further processing was carried out.

[0072] Determine the fractal dimension, number of layers, thickness of each layer, and duty cycle of each layer for the unit cell configuration of the three-dimensional structure;

[0073] Based on the principle that the smaller the fractal dimension, the better the electromagnetic loss performance, the configuration of the three-dimensional structure unit cell is changed by adjusting the thickness of each layer and the duty cycle of each layer until its electromagnetic loss performance meets the requirements.

[0074] This invention reveals the broadband electromagnetic loss characteristics of absorbing materials with topological structures through extensive research. Taking a multilayer honeycomb configuration as an example, through extensive research and experiments, the location of absorption peak frequencies and related influencing factors are analyzed. The influence of thickness and duty cycle on the location of absorption peak frequencies is determined. Based on the obtained characteristics, the configuration can be quickly adjusted.

[0075] (1) In the analysis of the factors affecting the location of the absorption peak frequency, the 01 honeycomb structure is taken as the research object. When the total thickness of the structure changes, the frequency of the absorption peak shifts to the lower frequency band as the thickness of each individual layer increases. The variation law of the reflection loss value of the peak point is different. The increase of the thickness of the surface layer (4th layer) will lead to a corresponding decrease in the reflection loss value and a narrowing of the frequency range of the peak point region. The variation law caused by the increase of the thickness of the middle layer (2nd and 3rd layers) is the opposite. Therefore, in the structural design, if effective absorption covering the low frequency range is considered, the total thickness should be increased while balancing the thickness matching of the surface layer and the middle layer to achieve a minimum reduction in reflection loss and a widening of the frequency range of the peak point region.

[0076] (2) When the total thickness of the structure remains constant, by adjusting the thickness of two of the layers, it is shown that as the thickness of the intermediate layer increases, the position of the absorption peak frequency point remains basically unchanged, the corresponding reflection loss value increases, and the frequency range of the peak point region widens. Therefore, in structural design, when the total thickness of the structure is constrained, the thickness of the intermediate layer or the surface layer can be adjusted to sacrifice part of the electromagnetic loss performance at the peak point, thereby widening the frequency range of the peak point region and achieving the technical indicators of the effective absorption frequency band.

[0077] (3) When the thickness remains constant and the duty cycle changes, the changes in the absorption peak frequency position caused by the change in the duty cycle of each layer are different. For the middle layer, as the duty cycle of the second layer decreases, the absorption peak frequency position moves towards higher frequencies, the corresponding reflection loss value decreases, and the frequency range of the peak point region narrows. As the duty cycle of the third layer decreases, the absorption peak frequency position remains basically unchanged, the reflection loss value corresponding to the first absorption peak decreases, the frequency range of the peak point region narrows, the reflection loss value corresponding to the second absorption peak increases, and the frequency range of the peak point region widens. For the surface layer, as the duty cycle of the fourth layer decreases, the absorption peak frequency position moves towards higher frequencies, the corresponding reflection loss value shows a decreasing trend, and the frequency range of the peak point region narrows. Therefore, in the structural design, the duty cycle of each layer represents the wall thickness of the honeycomb configuration. By increasing the wall thickness of the surface layer, the effective absorption bandwidth can be covered in the low-frequency band; by reducing the wall thickness of the middle layer, the electromagnetic loss performance at the peak point can be enhanced.

[0078] The present invention further provides a preferred embodiment, providing a design method for a three-dimensional structural unit cell configuration, comprising:

[0079] Simulation experiments were conducted on materials with currently designed three-dimensional structural configurations as unit cell configurations for all three-dimensional structural configurations to be designed to determine their electromagnetic loss performance; and a statistical relationship between the fractal dimension and electromagnetic loss performance of each three-dimensional structural unit cell configuration was constructed.

[0080] Based on the current application environment, a three-dimensional structural unit cell configuration that meets the electromagnetic loss performance requirements is selected according to the aforementioned statistical relationships; alternatively, if the currently used three-dimensional structural unit cell configuration has been determined, it is determined whether the electromagnetic loss performance of the current three-dimensional structural unit cell configuration meets the application requirements. If it does, the currently determined three-dimensional structural unit cell configuration is the final configuration; otherwise, following the principle that the smaller the fractal dimension, the better the electromagnetic loss performance, the three-dimensional structural unit cell configuration is changed by adjusting the thickness of each layer / duty cycle of each layer until its electromagnetic loss performance meets the requirements. Related adjustments in this scheme can also be made in accordance with the above rules.

[0081] To further illustrate the characteristics of the materials, three-dimensional parametric modeling of honeycomb and stepped cone structures was performed according to the description of the materials in this invention, ultimately resulting in seven different materials.

[0082] Example 1

[0083] honeycomb structure such as Figure 1 As shown, to calculate the fractal dimension of different fractal dimension structures, cubic meshes of different scales were used to contain configurations. The fractal dimensions of seven configurations were calculated by fitting the slope of the curve. The three-dimensional space occupied by cubic meshes with side lengths of 0.2 mm, 0.05 mm, and 0.002 mm were selected, and the number of meshes was counted. The statistical model of the fractal dimension of the configurations is as follows: Figure 2 As shown, the cross-sectional mesh of the configuration is as follows Figure 3 As shown. The fractal dimension of the configuration is obtained by fitting the slope of the curve to the fractal dimension of the configuration.

[0084] The geometric dimensions of the honeycomb structure are as follows:

[0085]

[0086] Example 2

[0087] Stepped pyramidal configuration, such as Figure 4 As shown, to calculate the fractal dimension of different fractal dimension structures, cubic meshes of different scales were used to contain configurations. The fractal dimensions of seven configurations were calculated by fitting the slope of the curve. The three-dimensional space occupied by cubic meshes with side lengths of 0.2 mm, 0.05 mm, and 0.002 mm were selected, and the number of meshes was counted. The statistical model of the fractal dimension of the configurations is as follows: Figure 5 As shown, the cross-sectional mesh of the configuration is as follows Figure 6 As shown. The fractal dimension of the configuration is obtained by fitting the slope of the curve to the fractal dimension of the configuration.

[0088] The geometric dimensions of the stepped cone structure are as follows:

[0089]

[0090] Example 3

[0091] The structure of a woodpile is as follows Figure 7 As shown, to calculate the fractal dimension of different fractal dimension structures, cubic meshes of different scales were used to contain configurations. The fractal dimensions of seven configurations were calculated by fitting the slope of the curve. The three-dimensional space occupied by cubic meshes with side lengths of 0.2 mm, 0.05 mm, and 0.002 mm were selected, and the number of meshes was counted. The statistical model of the fractal dimension of the configurations is as follows: Figure 8 As shown, the cross-sectional mesh of the configuration is as follows Figure 9 As shown. The fractal dimension of the configuration is obtained by fitting the slope of the curve to the fractal dimension of the configuration.

[0092] The geometric dimensions of the woodpile configuration are as follows:

[0093]

[0094] Example 4

[0095] Combination configuration 1 as Figure 10 As shown, to calculate the fractal dimension of different fractal dimension structures, cubic meshes of different scales were used to contain configurations. The fractal dimensions of seven configurations were calculated by fitting the slope of the curve. The three-dimensional space occupied by cubic meshes with side lengths of 0.2 mm, 0.05 mm, and 0.002 mm were selected, and the number of meshes was counted. The statistical model of the fractal dimension of the configurations is as follows: Figure 11 As shown, the cross-sectional mesh of the configuration is as follows Figure 12 As shown. The fractal dimension of the configuration is obtained by fitting the slope of the curve to the fractal dimension of the configuration.

[0096] The geometric dimensions of the stepped cone structure are as follows:

[0097]

[0098] Example 5

[0099] Combination configuration 2, such as Figure 13 As shown, to calculate the fractal dimension of different fractal dimension structures, cubic meshes of different scales were used to contain configurations. The fractal dimensions of seven configurations were calculated by fitting the slope of the curve. The three-dimensional space occupied by cubic meshes with side lengths of 0.2 mm, 0.05 mm, and 0.002 mm were selected, and the number of meshes was counted. The statistical model of the fractal dimension of the configurations is as follows: Figure 14 As shown, the cross-sectional mesh of the configuration is as follows Figure 15 As shown. The fractal dimension of the configuration is obtained by fitting the slope of the curve to the fractal dimension of the configuration.

[0100] The geometric dimensions of the stepped cone structure are as follows:

[0101]

[0102] Example 6

[0103] Combination configuration 3, such as Figure 16 As shown, to calculate the fractal dimension of different fractal dimension structures, cubic meshes of different scales were used to contain configurations. The fractal dimensions of seven configurations were calculated by fitting the slope of the curve. The three-dimensional space occupied by cubic meshes with side lengths of 0.2 mm, 0.05 mm, and 0.002 mm were selected, and the number of meshes was counted. The statistical model of the fractal dimension of the configurations is as follows: Figure 17 As shown, the cross-sectional mesh of the configuration is as follows Figure 18 As shown. The fractal dimension of the configuration is obtained by fitting the slope of the curve to the fractal dimension of the configuration.

[0104] The geometric dimensions of the stepped cone structure are as follows:

[0105]

[0106] Example 7

[0107] Combination configuration 4, such as Figure 19 As shown, to calculate the fractal dimension of different fractal dimension structures, cubic meshes of different scales were used to contain configurations. The fractal dimensions of seven configurations were calculated by fitting the slope of the curve. The three-dimensional space occupied by cubic meshes with side lengths of 0.2 mm, 0.05 mm, and 0.002 mm were selected, and the number of meshes was counted. The statistical model of the fractal dimension of the configurations is as follows: Figure 20 As shown, the cross-sectional mesh of the configuration is as follows Figure 21 As shown. The fractal dimension of the configuration is obtained by fitting the slope of the curve to the fractal dimension of the configuration.

[0108] The geometric dimensions of the stepped cone structure are as follows:

[0109]

[0110] The undisclosed technologies in this invention are common knowledge to those skilled in the art.

Claims

1. A three-dimensional structural configuration material, characterized in that: The material is constructed using a single-cell structure with geometric multi-scale characteristics. The single-cell structure is constructed using fractal dimension, number of layers, thickness of each layer, and duty cycle of each layer as common geometric feature parameters. The fractal dimension is used to quantitatively characterize the complexity of the three-dimensional structure single-cell configuration. The fractal dimension is calculated as a whole based on the specific three-dimensional structure single-cell configuration. The unit cell structures with geometric multi-scale characteristics include honeycomb configurations, stepped cone configurations, stacked wood configurations, box configurations, and combined configurations; the honeycomb configuration is a multi-layered honeycomb gradient arrangement stacked from largest to smallest; the stepped cone configuration is a multi-layered cube gradient arrangement stacked from largest to smallest; the stacked wood configuration is a multi-layered staggered arrangement of cuboids; the box configuration is a multi-layered cube gradient arrangement stacked from largest to smallest; and the combined configuration is a multi-layered arrangement of cuboids and boxes.

2. The three-dimensional structural configuration material according to claim 1, characterized in that: The fractal dimension is calculated in the following manner: Construct a geometric model of a three-dimensional structural unit cell configuration, and use cubic meshes of different scales to contain the three-dimensional space occupied by the geometric model; Calculate the number of cubic meshes containing objects, Nr; right and In least squares regression analysis, the slope of the fitted line is the fractal dimension. Where r is the side length of the cubic grid, and r decreases by a factor of 10 to cover at least 3 orders of magnitude.

3. A method for screening three-dimensional structural unit cell configurations, characterized in that... include: The material with the smallest fractal dimension was selected from all the three-dimensional structural configuration materials described in claim 1 as the configuration with the best electromagnetic loss performance to complete the screening.

4. A design method for a three-dimensional structural unit cell configuration, characterized in that... include: A three-dimensional structural configuration material as described in claim 1 was initially selected as the current design unit cell configuration for the three-dimensional structure. Simulation experiments were conducted to determine whether the electromagnetic loss performance of the current three-dimensional structural unit cell configuration met the application requirements. If it met the application requirements, the currently determined three-dimensional structural unit cell configuration was the final configuration; otherwise, further processing was performed. Determine the fractal dimension, number of layers, thickness of each layer, and duty cycle of each layer for the unit cell configuration of the three-dimensional structure; Based on the principle that the smaller the fractal dimension, the better the electromagnetic loss performance, the configuration of the three-dimensional structure unit cell is changed by adjusting the thickness of each layer and the duty cycle of each layer until its electromagnetic loss performance meets the requirements.

5. The design method for a three-dimensional structural unit cell configuration according to claim 4, characterized in that: The three-dimensional structure unit cell configuration is a multi-layer honeycomb configuration.

6. The design method for a three-dimensional structural unit cell configuration according to claim 5, characterized in that: During the adjustment process, if the duty cycle of each layer remains unchanged, the thickness adjustment is carried out according to the following rules: When the total thickness of the structure changes, as the thickness of each individual layer increases, the frequency of the absorption peak shifts to a lower frequency band; the increase in the thickness of the outermost layer leads to a decrease in the corresponding reflection loss value and a narrowing of the frequency range of the peak point region; the increase in the thickness of the middle layer leads to a decrease in the corresponding reflection loss value and a widening of the frequency range of the peak point region.

7. The design method for a three-dimensional structural unit cell configuration according to claim 5, characterized in that: During the adjustment process, if the total thickness of the configuration remains unchanged, the adjustment shall be carried out according to the following rules: By adjusting the thickness of the intermediate or surface layer, sacrificing some of the electromagnetic loss performance at the peak point (i.e., disregarding the positional change of the absorption peak frequency point), the frequency range of the region where the peak point is located is widened, thereby achieving the technical specifications of an effective absorption frequency band.

8. The design method for a three-dimensional structural unit cell configuration according to claim 5, characterized in that: During the adjustment process, if the configuration thickness remains unchanged, the duty cycle is adjusted according to the following rules: The duty cycle of each layer represents the wall thickness of the honeycomb structure. By increasing the wall thickness of the surface layer, the effective absorption bandwidth can be covered in the low-frequency band; by reducing the wall thickness of the middle layer, the electromagnetic loss performance at the peak point can be enhanced.

9. A design method for a three-dimensional structural unit cell configuration, characterized in that... include: Simulation experiments were conducted on the three-dimensional structural configuration material described in claim 1, which has been designed so far, as a unit cell configuration of all three-dimensional structures to be designed, to determine its electromagnetic loss performance. Construct a statistical relationship between the fractal dimension of each three-dimensional structure unit cell configuration and its electromagnetic loss performance; Based on the current application environment, a three-dimensional structural unit cell configuration that meets the electromagnetic loss performance requirements is selected according to the statistical relationship; or, if the currently used three-dimensional structural unit cell configuration has been determined, it is determined whether the electromagnetic loss performance of the current three-dimensional structural unit cell configuration meets the application requirements. If it meets the application requirements, the currently determined three-dimensional structural unit cell configuration is the final configuration; otherwise, according to the principle that the smaller the fractal dimension, the better the electromagnetic loss performance, the three-dimensional structural unit cell configuration is changed by adjusting the thickness of each layer / duty cycle of each layer of the current configuration until its electromagnetic loss performance meets the requirements.

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