Novel high-performance 3D printing wave-absorbing structure design method

Abstract

The invention belongs to the field of electromagnetic wave absorption, and particularly relates to a novel high-performance 3D printing wave absorption structure design method. According to the method, high-degree-of-freedom design of a wave absorbing structure is optimized, an ultra-wideband wave absorbing material is designed based on a functional unit, electromagnetic parameter gradient design is introduced by utilizing the characteristics that the types of wave absorbing wires, the number of configuration layers of the functional unit and structural parameters are variable, and electromagnetic parameter gradient optimization design is carried out by adjusting parameters of materials of all layers; the better wave-absorbing performance and the wider wave-absorbing bandwidth are realized; the wave-absorbing performance of the wave-absorbing structure is met, and meanwhile the mechanical bearing performance is achieved. According to the method, a multi-dimensional innovative design thought is carried out in the design of the wave-absorbing structure, target parameters can be set according to different application scenes, a design scheme is preferentially iterated by a computer program, and the method is a scheme for realizing the functional active design of the wave-absorbing structure. The method has the advantages of high performance, high universality, high efficiency and the like, is easy to implement industrially, and is suitable for popularization.

Description

Technical Field

[0001] This invention belongs to the field of electromagnetic wave absorption, specifically a novel high-performance 3D printing wave-absorbing structure design method, which designs ultra-wideband wave-absorbing materials based on functional units. Background Technology

[0002] As a type of electromagnetic functional material capable of absorbing electromagnetic wave energy and reducing reflection and scattering, radar-absorbing materials are key materials for improving the stealth performance of aircraft. Traditional "impregnated" honeycomb radar-absorbing materials are limited by the manufacturing process, and further performance improvements have encountered significant bottlenecks, severely restricting the survivability and penetration capabilities of stealth aircraft in the extremely complex environments of future air combat.

[0003] Additive manufacturing technology (i.e., 3D printing technology) has become an important technical means for preparing high-performance microwave absorbing structures. Compared with traditional microwave absorbing honeycomb materials, 3D printing technology offers new solutions for the design and manufacturing of microwave absorbing materials due to its advantages such as high design freedom, material saving, and rapid prototyping. It can achieve the design and fabrication of highly complex structures that are difficult to achieve with traditional processes, demonstrating great potential in the field of microwave absorbing materials. Addressing the problems of poor designability and insufficient microwave absorption performance of existing microwave absorbing honeycomb materials, 3D printing technology can be used to manufacture novel microwave absorbing structures based on functional units. By designing the shape, size, thickness, distribution, and electromagnetic parameters of the functional units, impedance matching of the microwave absorption performance can be achieved, significantly improving absorption efficiency.

[0004] There have been reports on the preparation of novel microwave absorbing materials using 3D printing technology. For example, patent CN117430754A describes a method for preparing a photocurable 3D printed resin-based gradient microwave absorbing structure. This involves uniformly mixing electromagnetic wave absorber powder, photocurable resin, photoinitiator, and reactive diluent to obtain a photocurable 3D printing slurry, which is then layered to create the final microwave absorbing structure. Another patent, CN111873404A, describes a method for preparing a 3D-printed spatial multilayer microwave absorbing structure. This method uses 3D printing technology to manufacture a multilayer microwave absorbing structure composed of multiple structural units. Each structural unit consists of a frame structure and a microwave absorbing filler, ensuring the overall microwave absorption performance and mechanical properties of the structure. Patent CN119601980A describes a lightweight broadband microwave absorbing structure based on 3D printing and a resistive film, and its preparation method. This involves introducing a 3D-printed structure with two different sizes of regular hexagonal prisms as periodic units into a single-layer resistive film microwave absorbing structure. By optimizing the 3D-printed structure and its dimensions, as well as the resistive film resistance, a microwave absorbing structure with small thickness and weight is obtained, while also exhibiting excellent microwave absorption performance. Patent CN114311654A describes a metamaterial microwave absorbing structure based on 3D printing technology, its preparation method, and its application. This patent prepares a carbonyl iron-polyether ether ketone 3D-printed composite filament, designs a pyramid-shaped flat plate microwave absorbing structure, and obtains it through 3D printing, ensuring the mechanical and microwave absorption properties of the metamaterial microwave absorbing structure.

[0005] By optimizing the design of the shape, size, thickness, distribution, and electromagnetic parameters of functional units, a variety of 3D printed microwave absorbing structures with different properties can be realized. However, there is currently a lack of efficient design methods for high-performance 3D printed microwave absorbing structures. Summary of the Invention

[0006] To address the aforementioned problems and shortcomings, and to solve the issues of poor designability and insufficient absorption performance of existing absorbing honeycomb structures, this invention provides a novel high-performance 3D-printed absorbing structure design method. Based on functional unit design of ultra-wideband absorbing materials, the method utilizes the flexibility and high degree of freedom of 3D printing technology to fabricate absorbing structures. Furthermore, by considering changes in the type of absorbing filament, functional unit configuration, and structural parameters, the method achieves controllable design of the required electromagnetic parameters. This improves the material's loss capacity and impedance matching, resulting in high-performance absorption. The design scheme can be adjusted according to the actual application of the absorbing structure, exhibiting good versatility. Computer programs can be used to quickly complete optimization design and scheme iteration, and combined with 3D printing technology, mass production can be achieved, resulting in high production efficiency.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A novel high-performance 3D-printed microwave absorbing structure design method includes the following steps:

[0009] Step 1: Use absorbing filaments suitable for 3D printing as the intrinsic material.

[0010] Step 2: Based on the equivalent medium theory, by adjusting the duty cycle of the intrinsic material, gradient materials with different equivalent electromagnetic parameters are obtained, and a gradient material library is constructed.

[0011] Step 3: Based on the actual application and mechanical load-bearing performance requirements of the target absorbing structure, determine the total height, number of layers, and functional unit configuration type of the absorbing structure.

[0012] Step 4: Based on the total height and number of layers of the absorbing structure determined in Step 3, set optimization target parameters (such as average reflectivity, bandwidth, etc.) according to electromagnetic performance requirements, optimize and determine the gradient material type and corresponding layer height of each layer of the target absorbing structure.

[0013] Step 5: Based on the functional unit configuration category determined in Step 3 and the gradient material type and corresponding layer height of each layer of the absorbing structure determined in Step 4, determine the period and wall thickness of each layer structure by using the equivalent method where the equivalent duty cycle of each layer structure is consistent with the duty cycle of the corresponding gradient material, and complete the design.

[0014] Furthermore, the functional unit configurations include square hole configuration, internal hexagonal configuration, and woodpile configuration.

[0015] Furthermore, the electromagnetic parameter gradient is designed as at least one of the three-dimensional layer gradient of the type of absorbing filament, the three-dimensional layer gradient of the functional unit configuration type and size, to meet the diversity and universality of different application scenarios.

[0016] Furthermore, the matrix material of the absorbing filament is at least one of PEEK, ABS, PLA, PI or PA, and the absorbent filler is a carbon-based material such as carbon black, carbon nanotubes or carbon fibers, or a metal material such as carbonyl iron, or a ceramic material such as silicon nitride or silicon carbide.

[0017] Furthermore, the functional unit configuration has at least two layers to ensure the mechanical load-bearing performance of the target wave-absorbing structure.

[0018] This invention optimizes the high-degree-of-freedom design of microwave absorbing structures by utilizing the variable characteristics of absorbing filament types, the number of functional unit layers, and structural parameters. It introduces electromagnetic parameter gradient design, optimizing the electromagnetic parameters by adjusting the parameters of each layer to achieve superior absorption performance and a wider absorption bandwidth. This results in excellent absorption performance while maintaining robust mechanical load-bearing capacity. Through innovative design approaches across multiple dimensions, this invention allows for setting target parameters based on different application scenarios. A computer program iteratively selects the best design solution, representing a proactive and functional design approach for microwave absorbing structures.

[0019] In summary, compared with existing technologies, this invention has advantages such as high performance, high versatility, and high efficiency, and is easy to implement industrially, making it suitable for widespread application. During use, the type of 3D printing filament, the configuration of functional units, the geometric parameters of functional units, and the number of gradient layers in the absorbing structure can all be set with appropriate optimization target parameters according to requirements, such as absorbing bandwidth, mean value, and mechanical properties. Through continuous optimization and iteration, a design scheme that meets the optimization targets is finally obtained. Attached Figure Description

[0020] Figure 1 The electromagnetic parameter curves of the PEEK-carbon black absorbing filament in the example are shown.

[0021] Figure 2 This is a schematic diagram of the equivalent duty cycle model for an example embodiment;

[0022] Figure 3 The following is a graph showing the dielectric constants of eight graded materials from the material library used in the examples.

[0023] Figure 4 A schematic diagram of the square-hole gradient absorbing structure and a graph showing the reflection simulation results are provided for the embodiment.

[0024] Figure 5 This is a schematic diagram of the gradient-variable hexagonal absorber structure in the embodiment and a graph showing the reflection rate simulation results.

[0025] Figure 6 A schematic diagram of the gradient-varying wood-pile structure and a graph showing the simulation results of the reflectivity are provided for this embodiment.

[0026] Figure 7 This is a flowchart of the present invention. Detailed Implementation

[0027] The technical solution of the present invention will be further described in detail below with reference to the embodiments and accompanying drawings.

[0028] In this embodiment, the 3D-printed absorbing filament used is PEEK-carbon black absorbing filament. Several injection molding processes were repeated to obtain several sets of coaxial rings of absorbing filament with the same composition. Electromagnetic parameters from 0.5 to 18 GHz were tested on a coaxial electromagnetic parameter testing platform. The test results are as follows: Figure 1 As shown.

[0029] like Figure 2 The diagram shown is a schematic of the equivalent duty cycle model according to an embodiment of the present invention. Based on the equivalent medium theory, the formulas for calculating the equivalent electromagnetic parameters of this model can be obtained as follows:

[0030] ε=ε a [(2-g)ε0+g×ε a ] / [(2-g)εa +g×ε0]

[0031] g = 1 - a 2 / b 2

[0032] Where ε is the electromagnetic parameter obtained after the equivalent process; ε a ε is the dielectric constant of the intrinsic material (absorbing wire); ε0 is the relative dielectric constant of air; g is the equivalent duty cycle; a is the side length of the hollow part; b is the side length of the solid part.

[0033] Based on this equivalent model, eight gradient materials with different equivalent electromagnetic parameters were obtained in this embodiment. The names and equivalent duty cycles of each gradient material are M1-7.84%; M2-15.36%; M3-29.44%; M4-42.24%; M5-53.76%; M6-64%; M7-84%; and M8-100%. The real parts of the dielectric constants of the eight gradient materials in the material library are as follows: Figure 3 As shown in (a), the imaginary part is as follows: Figure 3 As shown in (b).

[0034] In this embodiment, the total height of the target absorbing structure is 30mm, the number of layers is 4, and the target reflectivity optimization is 2~4GHz: -10dB; 4~8GHz: -15dB; 8~12GHz: -20dB; 12~18GHz: -15dB.

[0035] Figure 4 (a) is a schematic diagram of a square hole gradient absorbing structure model with a total height of 30mm. The first layer (bottom layer) has a period of 5mm, a wall thickness of 3mm, and a height of 8mm; the second layer has a period of 5mm, a wall thickness of 1.2mm, and a height of 4mm; the third layer has a period of 15mm, a wall thickness of 1.2mm, and a height of 12mm; and the fourth layer (top layer) has a period of 15mm, a wall thickness of 0.6mm, and a height of 6mm. Figure 5 (b) shows the simulation results of the reflectivity of the square hole configuration. It can be seen that its average reflectivity is: 2~4GHz: -13.5dB; 4~8GHz: -14.7dB; 8~12GHz: -23.5dB; 12~18GHz: -18.3dB. The results basically meet the pre-set optimization objectives, which proves the effectiveness of the optimization design method and also proves that the gradient square hole structure can achieve good broadband absorption performance.

[0036] Figure 5(a) is a schematic diagram of the gradient wave-absorbing structure model with an internal hexagonal configuration. The total height is 30mm. The first layer (bottom layer) has a period of 9mm, a wall thickness of 4mm, and a height of 9mm; the second layer has a period of 9mm, a wall thickness of 0.8mm, and a height of 6mm; the third layer has a period of 9mm, a wall thickness of 0.4mm, and a height of 8mm; and the fourth layer (top layer) has a period of 18mm, a wall thickness of 0.4mm, and a height of 7mm. Figure 6 (b) shows the simulation results of the reflectivity of the hexagonal internal structure. The average reflectivity is: 2–4 GHz: -12.6 dB; 4–8 GHz: -15.6 dB; 8–12 GHz: -19.7 dB; 12–18 GHz: -21.5 dB. The results basically meet the pre-set optimization objectives, demonstrating the effectiveness of the optimization design method and proving that the gradient hexagonal internal structure can achieve good broadband absorption performance.

[0037] Figure 6 (a) is a schematic diagram of a gradient-varying wave-absorbing structure model with a wood stack configuration. The total height is 30mm. The first layer (bottom layer) has a period of 5mm, a wall thickness of 4mm, and a height of 9mm; the second layer has a period of 5mm, a wall thickness of 1.2mm, and a height of 7mm; the third layer has a period of 10mm, a wall thickness of 1.2mm, and a height of 8mm; and the fourth layer (top layer) has a period of 10mm, a wall thickness of 0.6mm, and a height of 6mm. Figure 6 (b) shows the simulation results of the reflectivity of the woodpile configuration. The average reflectivity is: 2–4 GHz: -12.1 dB; 4–8 GHz: -16.0 dB; 8–12 GHz: -23.4 dB; 12–18 GHz: -18.6 dB. The results meet the set optimization objectives, demonstrating the effectiveness of the optimization design method and proving that the gradient woodpile structure can achieve good broadband absorption performance.

[0038] As can be seen from the above embodiments, the present invention provides a novel gradient optimization design method for high-performance 3D printed microwave absorbing structures based on functional units, the process of which is as follows: Figure 7As shown. Addressing the current limitations of poor designability and insufficient absorption performance in absorbing honeycomb structures, this invention constructs a gradient material library based on absorbing filaments, utilizing equivalent medium theory and an equivalent duty cycle model. On one hand, by changing the geometric parameters of each layer and arranging materials according to their duty cycles, controllable design of the required electromagnetic parameters can be achieved. On the other hand, appropriate optimization target parameters, such as bandwidth and mean value, are set according to requirements. Through continuous optimization and iteration, a design scheme that meets the optimization target is finally obtained. Ultimately, the optimized gradient 3D printing structure parameter scheme is mapped to specific functional unit structures, such as the square hole configuration, internal hexagonal configuration, and woodpile configuration in the embodiment, ensuring that the equivalent duty cycle is consistent with the duty cycle of the optimized gradient 3D printing structure parameter scheme. This invention can adjust the functional unit configuration and geometric parameters according to the optimization target, achieving gradient changes in electromagnetic parameters as needed, resulting in high performance, high versatility, and high efficiency.

Claims

1. A novel high-performance 3D printing wave-absorbing structure design method, characterized in that, The method comprises the following steps: Step 1: using a wave-absorbing wire material suitable for 3D printing as an intrinsic material; Step 2: based on the equivalent medium theory, a gradient material library is constructed by adjusting the duty cycle of the intrinsic material to obtain different equivalent electromagnetic parameters; Step 3: based on the actual application and mechanical bearing performance requirements of the target wave-absorbing structure, the total height, layer number and functional unit configuration type of the wave-absorbing structure are determined; Step 4: based on the total height and layer number determined in step 3, the optimization target parameters are set according to the electromagnetic performance requirements, and the gradient material type and corresponding layer height of each layer of the target wave-absorbing structure are optimized and determined; Step 5: based on the functional unit configuration type determined in step 3 and the gradient material type and corresponding layer height of each layer of the wave-absorbing structure determined in step 4, the period and wall thickness of each layer structure are determined by using the equivalent method of consistent equivalent duty cycle and corresponding gradient material duty cycle, and the design is completed.

2. The novel high-performance 3D printing wave-absorbing structure design method of claim 1, characterized in that: The functional unit configuration includes a square hole configuration, an internal hexagonal configuration and a wood pile configuration.

3. The novel high-performance 3D printing wave-absorbing structure design method of claim 1, wherein: The electromagnetic parameter gradient design is at least one of a three-dimensional layer number gradient of the wave-absorbing wire material type and a three-dimensional layer number gradient of the functional unit configuration type and size.

4. The novel high-performance 3D printing wave-absorbing structure design method of claim 1, wherein: The base material of the wave-absorbing wire material is at least one of PEEK, ABS, PLA, PI or PA, and the absorbent filler is at least one of carbon black, carbon nanotube, carbon fiber carbon-based material, or carbonyl iron metal material, or silicon nitride, silicon carbide ceramic material.

5. The novel high-performance 3D printing wave-absorbing structure design method of claim 1, wherein: The functional unit configuration layer number is at least 2 layers.

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