A bionic double-scale lattice metamaterial with high damage tolerance and electromagnetic absorption performance and a design method thereof

Abstract

This invention discloses a biomimetic dual-scale lattice metamaterial with high damage tolerance and electromagnetic absorption performance, and its design method. It belongs to the field of integrated design technology of damage tolerance design and electromagnetic function. This invention uses finite element simulation software, based on a first-order unit lattice, and adopts a recursive modeling method to design a second-order dual-scale lattice structure. By rationally designing the topology and size parameters of the dual-scale lattice, the structure maintains a high electromagnetic absorption rate over a wide frequency range, improves the damage tolerance of the structure, and, while maintaining a low relative density, makes it have high specific stiffness and specific strength, thus achieving mechanical-electromagnetic integrated optimization.

Description

Technical Field

[0001] This invention belongs to the field of integrated design technology of damage tolerance design and electromagnetic function, specifically relating to a biomimetic dual-scale lattice metamaterial with high damage tolerance and electromagnetic absorption performance and its design method. Background Technology

[0002] Biomimetic dual-scale metamaterials refer to structural materials that mimic the multi-level structures of natural organisms, such as honeycomb materials, skeletons, and starfish skeletons. They are made using new nanomaterials such as atomic crystals, gradient alloys, polymers, or ceramics, and processed through additive / subtractive / etching techniques. These materials have a multi-level nano-microlattice structure, low electromagnetic scattering, and integrated load-bearing capacity. They can provide new possibilities for developing lighter / stronger, more stable, reliable, and highly survivable military platforms (fighter jets, portable micro-drones, and warships, etc.).

[0003] Inspired by natural multi-level hierarchical systems, biomimetic dual-scale metamaterials with integrated multifunctionality have been designed, exhibiting a series of novel properties, such as ultra-high stiffness-to-weight ratio, excellent energy absorption capacity, damage resistance, and electromagnetic absorption performance. These hierarchical structures are designed through a multi-scale collaborative strategy, spanning lengths from nanometers to centimeters, achieving multifunctional integration. At the macroscopic level, repeating units such as honeycomb or truss structures provide overall strength and stiffness. At the microscopic level, complex lattice structures, including micropores or periodic unit cells, promote efficient stress distribution, inhibit crack propagation, and enhance damage resistance.

[0004] Metamaterials have broad application prospects in the aerospace field. Multi-level biomimetic micro / nano lattice structures, through intelligent and ordered design, can achieve cross-scale synergistic enhancement effects. In addition to providing main load-bearing performance, they can also effectively avoid electromagnetic detection, achieving stealth for weapon systems. However, as a source of damage to critical parts of weapon platforms (fuselage surfaces, cockpits, radar components, and missile bodies, especially during the design and manufacturing process, where damage tolerance design requires aircraft structures to maintain sufficient strength and stiffness even if damage is not detected, taking into account various potential damages), metamaterials inevitably suffer damage and cracking due to collisions, scratches, or natural aging. This leads to a decline in material performance or even complete failure, seriously affecting the battlefield survivability and integrity of weapon systems. Therefore, in-depth research and development of a biomimetic dual-scale lattice metamaterial with a lightweight, high-performance structure, high damage tolerance, and electromagnetic absorption properties has significant military value. Summary of the Invention

[0005] This invention provides a biomimetic dual-scale lattice metamaterial with high damage tolerance and electromagnetic absorption performance, and its design method. Through multi-level topological structure design, the specific stiffness, specific strength, damage tolerance and broadband electromagnetic absorption performance of the lattice structure are synergistically controlled.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A design method for biomimetic dual-scale lattice metamaterials with high damage tolerance and electromagnetic absorption properties includes the following steps: S1: Using finite element simulation software, based on first-order Octet (Oct), Octahedra (Octa), and Dodecahedron (Dode) lattices, a recursive modeling method was used to design second-order Octet-Octet (Oct-Oct), Octet-Octahedra (Oct-Octa), and Octet-Dodecahedron (Oct-Dode) dual-scale lattice structures; simultaneously, an Octet single-scale lattice structure with the same unit size and relative density as the above-mentioned second-order structures was established as a control. S2: Quasi-static uniaxial compression numerical simulation of the dual-scale lattice structure constructed in S1; S3: The periodic array of dual-scale lattice units constructed in S1 is subjected to damage, and finite element damage models under different topological configurations are obtained. Quasi-static uniaxial compression numerical simulations are then performed. At the same time, the same damage conditions are applied to the first-order Oct single-scale lattice structure constructed in S1, and the corresponding quasi-static uniaxial compression numerical simulations are performed. S4: Perform electromagnetic simulation on the dual-scale lattice structure constructed in S1; simultaneously, under the same simulation conditions, perform electromagnetic simulation on the Oct single-scale lattice structure constructed in S1.

[0008] The specific steps of S1 described above are as follows: S11. Establish 0th-order element: Establish an isotropic elastoplastic cylindrical rod as the minimum component for subsequent assembly and recursion; S12. Establishing a first-order element: Using three typical lattice topologies of Oct, Octa, and Dode as topological targets, and based on the spatial geometric distribution of the selected topological element, multiple 0th-order members are connected along a preset direction through a common node method to form a first-order element. S13. Establishing a second-order unit: Based on this, scale recursion is performed to set the Oct lattice topology as the overall topological framework of a second-order lattice. In the second-order Oct lattice structure, each macroscopic pillar is arrayed and replicated from the first-order lattice along the pillar axis according to the hierarchical principle at a topological periodicity l, and the repeating bodies are spliced ​​at the end nodes to form a continuous structure, ensuring the overall topological closure and continuous force transmission of the second-order unit. S14. Establish a first-order Oct single-scale lattice structure with the same relative density as the generated second-order Oct-Oct, Oct-Octa, and Oct-Dode dual-scale lattice structures. This structure is used to compare and analyze the second-order dual-scale lattice structure under the same simulation conditions to verify the advantages of the dual-scale structure in terms of macroscopic mechanical / electromagnetic properties.

[0009] The specific steps of S2 are as follows: S21. Finite element modeling is performed on the dual-scale lattice structure obtained in S1 to obtain finite element models under different topological configurations. S22. Simulation analysis is performed on finite element models with different geometric parameters to simulate the mechanical behavior of a dual-scale lattice structure under quasi-static uniaxial compression.

[0010] The specific steps for S3 are as follows: S31. Periodically array the dual-scale lattice structure obtained in S1 and introduce damage to obtain finite element damage models of dual-scale lattice structures under different topological configurations. S32. Simulation analysis of finite element damage models under different geometric parameters is performed to simulate the damage behavior of a dual-scale lattice structure under quasi-static uniaxial compression. S33. Under the same damage conditions, perform quasi-static uniaxial compression simulation on the first-order Oct single-scale lattice structure constructed in step S1, and compare the simulation results with those of the two-scale lattice structure.

[0011] The specific steps of S4 are as follows: S41. Finite element modeling is performed on the dual-scale lattice structure obtained in S1 to obtain finite element models under different topological configurations. S42. Perform electromagnetic simulation analysis on finite element models with different geometric parameters to simulate the electromagnetic response of a dual-scale lattice structure under broadband plane wave incidence. S43. Under the same simulation conditions, perform electromagnetic simulation on the first-order Oct single-scale lattice structure constructed in S1, and compare its simulation results with the electromagnetic response of the two-scale lattice structure.

[0012] Beneficial effects: This invention provides a biomimetic dual-scale lattice metamaterial with high damage tolerance and electromagnetic absorption properties, and its design method, which has the following advantages compared with the prior art: 1. A biomimetic two-scale metamaterial is designed using a two-scale lattice topology method, which achieves high specific stiffness and specific strength while maintaining low relative density, thus enabling lightweight and high load-bearing capacity. 2. When local damage occurs in the dual-scale lattice structure, the load-bearing capacity of the structure can be maintained, that is, the damage tolerance of the structure is improved; compared with the single-scale lattice, the decrease in specific stiffness of the dual-scale lattice structure of the present invention is significantly reduced. 3. By rationally designing the topology and size parameters of the dual-scale lattice, the structure maintains a high electromagnetic absorption rate over a wide frequency band, achieving integrated mechanical-electromagnetic optimization. Compared with single-scale lattices, the dual-scale lattice structure of this invention exhibits significant advantages in electromagnetic absorption. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of a two-scale lattice structure with different topological configurations designed by computer in an embodiment of the present invention.

[0014] Figure 2 The figures show (a) compressive stress-strain curves and (b) specific stiffness, specific strength, and failure strain results of different topological configurations of dual-scale lattice structures in the embodiments of the present invention.

[0015] Figure 3 The figures show the reduction in specific stiffness and specific strength of different topological configurations of dual-scale lattice structures under first / second-order damage compared to the intact structure, and their comparison with the single-scale structure under the same damage conditions.

[0016] Figure 4 The electromagnetic wave absorption, reflection, and transmission curves of different topological configurations of dual-scale lattice structures in the embodiments of the present invention are shown, along with their comparison with those of single-scale structures. Detailed Implementation

[0017] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments:

[0018] like Figure 1 As shown, this invention provides a design method for a biomimetic dual-scale lattice metamaterial with high damage tolerance and electromagnetic absorption properties, specifically including the following steps:

[0019] S1: Establish isotropic elastoplastic cylindrical rods as 0th-order units, serving as the smallest components for subsequent assembly and recursion; using Oct, Octa, and Dode typical lattice topologies as topological targets, and based on the spatial geometric distribution of the selected topological units, connect multiple 0th-order unit rods along a preset direction using a common-node method to form 1st-order units; on this basis, perform scale recursion, setting the Oct lattice topology as the overall topological framework of a 2nd-order lattice. In the 2nd-order Oct lattice structure, each macroscopic pillar is arrayed and replicated along the pillar axis of the 1st-order lattice according to the hierarchical principle, with the repeating bodies spliced ​​at the end nodes to form a continuous structure, ensuring the overall topological closure and continuous force transmission of the 2nd-order unit.

[0020] S2: Establish a first-order Oct single-scale lattice structure with the same relative density as the generated second-order Oct-Oct, Oct-Octa, and Oct-Dode dual-scale lattice structures. This structure is used to compare and analyze the second-order dual-scale lattice structure under the same simulation conditions to verify the advantages of the dual-scale structure in terms of macroscopic mechanical / electromagnetic properties.

[0021] S3: Perform quasi-static uniaxial compression numerical simulation on the constructed two-scale lattice structure.

[0022] S4: Damage is introduced into the constructed dual-scale lattice unit periodic array to obtain finite element damage models under different topological configurations, and quasi-static uniaxial compression numerical simulations are performed; at the same time, the same damage conditions are applied to the constructed Oct single-scale lattice structure, and corresponding quasi-static uniaxial compression numerical simulations are performed.

[0023] S4: Perform electromagnetic simulation on the dual-scale lattice structure constructed in step S1; simultaneously, under the same simulation conditions, perform electromagnetic simulation on the Oct single-scale lattice structure constructed in step S1.

[0024] In this embodiment, as Figure 1 As shown, based on the constructed macroscopic equivalent mechanical performance ensemble characterization model of periodic microstructure unit cells under complex uncertainty conditions, and combined with the design requirements and constraints of typical military platform load-bearing structures, Oct, Octa, and Dode lattices are selected as first-order basic configurations; and a second-order Oct lattice structure is used as the macroscopic topological framework. The first-order lattices are periodically arranged and spliced ​​along the direction of the second-order pillars according to predetermined topological rules, thereby forming a dual-scale hierarchical lattice structure. Further, the geometric and topological parameters related to the dual-scale configuration are determined, including the size of the first-order lattice unit, the size of the second-order lattice unit, and the number of repeating first-order lattices / topological units in the second-order structure, etc., and a geometric model of the dual-scale lattice structure is established accordingly. At the lattice unit level, the unit size is achieved by adjusting the pillar length; at the structural level, the number of repeating first-order lattices (or the number of topological units) in the second-order structure is controlled by coordinating the scale ratio of the first-order and second-order lattice units. The approximate values ​​of the relative densities of the first-order Oct, Octa, and Dode lattice structures are given by the following formula: , , .

[0025] The relative density of a second-order lattice structure is derived by multiplying the relative density of a first-order unit cell by the relative density of the substructures in the second-order lattice structure.

[0026] In this embodiment, the specific process of performing quasi-static compression simulation is as follows:

[0027] A dual-scale lattice structure finite element model was established, with dimensions of 60mm×60mm×60mm. A rigid plate with a thickness of 10mm and length and width of 200mm was used as the indenter of the compression testing machine, and the indenter was defined as a rigid body. The material properties and cross-sectional properties of the model and the upper and lower indenters were defined, and solid elements were created.

[0028] The normal contact behavior between the indenter and the model is defined as hard contact, and the tangential contact behavior is defined as frictional contact with a friction coefficient of 0.3.

[0029] Following the quasi-static compression test, a quasi-static displacement load of 20 mm was applied to the upper platen, while the lower platen was completely fixed in its translational and rotational degrees of freedom. The compressive strain rate was taken as 0.1 s². -1 ...

[0030] After assembly, set up the analysis step and create the process output.

[0031] A segmented elastoplastic model based on the maximum plastic failure strain criterion is defined for failure determination.

[0032] Compressive strain is defined as ε = ΔL / L0, where ΔL is the compressive displacement in the loading direction and L0 is the initial lattice length. Compressive stress σ = F / A, where F is the reaction force at the interface between the lattice and the rigid pressure plate, and A is the contact area.

[0033] Relevant data were extracted and processed to obtain macroscopic parameters such as specific stiffness, specific strength, and fracture strain of the dual-scale structure, thereby characterizing its mechanical properties.

[0034] The specific steps of step S3 are as follows:

[0035] S31. Periodically array the dual-scale lattice structure obtained in S1 and introduce damage to obtain finite element damage models of dual-scale lattice structures under different topological configurations.

[0036] S32. Simulation analysis of finite element damage models under different geometric parameters is performed to simulate the damage behavior of a dual-scale lattice structure under quasi-static uniaxial compression.

[0037] S33. Periodically array the Oct single-scale lattice structure obtained in S1 and introduce damage. Under the same damage conditions as the dual-scale lattice structure, perform quasi-static uniaxial compression simulation analysis on the single-scale lattice structure to simulate its damage behavior under quasi-static uniaxial compression.

[0038] In this embodiment, the specific process of performing quasi-static compression simulation is as follows:

[0039] A two-scale lattice structure finite element model was established, consisting of a periodic array of 3×3×3 second-order lattice units, with model dimensions of 180mm×180mm×180mm. First-order / second-order struts were removed to introduce first-order / second-order damage within the model. The finite element model was meshed using Timoshenko three-node beam elements. A rigid plate with a thickness of 10mm and dimensions of 200mm was constructed as the indenter of the compression testing machine. The indenter was defined as a rigid body, and a solid mesh was created for the rigid structure. The material and section properties of the model and the upper and lower indenters were defined.

[0040] The normal contact behavior between the indenter and the model is defined as hard contact, and the tangential contact behavior is defined as frictional contact with a friction coefficient of 0.3.

[0041] Following a quasi-static compression test, a quasi-static displacement load of 60 mm was applied to the upper platen, while the lower platen was completely fixed in its translational and rotational degrees of freedom. The compressive strain rate was taken as 0.1 s². -1 .

[0042] After assembly, set up the analysis step and create the process output.

[0043] A segmented elastoplastic model based on the maximum plastic failure strain criterion is defined for failure determination.

[0044] Extract relevant data and process the data to evaluate its damage tolerance performance.

[0045] The specific steps of step S4 are as follows:

[0046] S41. Finite element modeling is performed on the dual-scale lattice structure obtained in S1 to obtain finite element models under different topological configurations.

[0047] S42. Perform electromagnetic simulation analysis on finite element models with different geometric parameters to simulate the electromagnetic response of a two-scale lattice structure under broadband plane wave incidence.

[0048] S43. Under the same simulation conditions, perform electromagnetic simulation analysis on the Oct single-scale lattice structure obtained in S1 to simulate the electromagnetic response of the single-scale lattice structure under broadband plane wave incidence.

[0049] In this embodiment, the specific process of performing electromagnetic simulation is as follows:

[0050] A three-dimensional geometric model of a two-scale lattice structure is established, the dielectric constant and magnetic permeability of the lattice material and the background medium are defined, and the model is discretized using a quadrilateral mesh.

[0051] Set periodic boundary conditions in the x and y directions and free boundary conditions in the z direction for the model.

[0052] Create a frequency domain solver, set the simulation frequency domain to 4-18GHz, and configure the solution accuracy / convergence threshold.

[0053] In model z min With z max Set the excitation port and monitor on the end face.

[0054] Run the simulation, output the results and perform post-processing to evaluate the electromagnetic performance of the structure in the specified frequency domain.

[0055] Figure 2 The specific stiffness values ​​of the Oct-Oct, Oct-Octa, and Oct-Dode two-scale lattice structures are 99.78, 75.74, and 22.98 kPa·m, respectively. 3 / kg, with corresponding specific strength values ​​of 6.70, 3.84 and 2.81 kPa·m, respectively. 3 / kg. Among them, the Oct-Oct configuration exhibits the highest specific performance.

[0056] Figure 3 The load-bearing capacity of the two-scale lattice structure varies with the damage mode and damage density. A comparison with a single-scale structure of equal relative density / size shows that, at the same damage density, the two-scale structure exhibits a smaller decrease in specific stiffness, highlighting its superior damage tolerance.

[0057] Figure 4 The dual-scale lattice structure maintains an absorption rate higher than 85% in the 4-18 GHz frequency range, with some frequency bands showing an absorption rate close to 100%. Comparison with single-scale structures of equal relative density and size demonstrates that the electromagnetic absorption rate of the dual-scale lattice structure is significantly superior to that of the single-scale lattice structure, verifying the superiority of the dual-scale lattice structure in terms of electromagnetic absorption efficiency and broadband absorption.

[0058] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements without departing from the principle of the present invention, and these improvements should also be considered within the scope of protection of the present invention.

Claims

1. A design method for biomimetic dual-scale lattice metamaterials with high damage tolerance and electromagnetic absorption properties, characterized in that, Includes the following steps: A second-order dual-scale lattice structure was designed using finite element simulation software and a recursive modeling method based on a first-order unit lattice.

2. The design method for biomimetic dual-scale lattice metamaterials with high damage tolerance and electromagnetic absorption properties according to claim 1, characterized in that, The first-order unit cell lattice is a first-order Octet, Octahedra, or Dodecahedron lattice.

3. The design method for biomimetic dual-scale lattice metamaterials with high damage tolerance and electromagnetic absorption properties according to claim 1 or 2, characterized in that, The design process of the first-order unit lattice is as follows: an isotropic elastoplastic cylindrical rod is established as the 0th-order unit, which serves as the smallest component for subsequent assembly and recursion; taking Octet, Octahedra, and Dodecahedron as three typical lattice topologies as topological targets, multiple 0th-order rods are connected along a preset direction by sharing nodes according to the spatial geometric distribution of the selected topological unit to form a first-order unit lattice.

4. The design method for biomimetic dual-scale lattice metamaterials with high damage tolerance and electromagnetic absorption properties according to claim 3, characterized in that, The design process of the second-order dual-scale lattice structure is as follows: Based on the first-order unit lattice, scale recursion is performed to set the topology of the first-order unit lattice as the overall topological framework of the second-order lattice. In the second-order lattice structure, each macroscopic pillar is arrayed and replicated by the first-order lattice along the pillar axis according to the hierarchical principle and the topological periodicity. The repeating bodies are spliced ​​at the end nodes to form a continuous structure, ensuring the topological closure and continuous force transmission of the second-order unit as a whole.

5. The design method for a biomimetic dual-scale lattice metamaterial with high damage tolerance and electromagnetic absorption properties according to claim 4, characterized in that, The geometric and topological parameters associated with two-scale lattice structures include the size of the first-order lattice unit, the size of the second-order lattice unit, and the number of first-order lattice repeats / topological units contained in the second-order structure.

6. The design method for a biomimetic dual-scale lattice metamaterial with high damage tolerance and electromagnetic absorption properties according to claim 4, characterized in that, At the lattice unit level, the unit size is achieved by adjusting the length of the struts.

7. The design method for a biomimetic dual-scale lattice metamaterial with high damage tolerance and electromagnetic absorption properties according to claim 4, characterized in that, At the structural level, the number of repeating first-order lattices in a second-order structure is controlled by synergistically regulating the size ratio of first-order to second-order lattice units.

8. The design method for a biomimetic dual-scale lattice metamaterial with high damage tolerance and electromagnetic absorption performance according to claim 2, characterized in that, The approximate values ​​for the relative densities of first-order Oct, Octa, and Dode lattice structures are given by the following equation: ， ， 。 9. The design method for biomimetic dual-scale lattice metamaterials with high damage tolerance and electromagnetic absorption properties according to claim 2 or 8, characterized in that, The relative density of a second-order lattice structure is derived by multiplying the relative density of a first-order unit cell by the relative density of the substructures in the second-order lattice structure.

10. A biomimetic dual-scale lattice metamaterial with high damage tolerance and electromagnetic absorption properties, characterized in that, The biomimetic dual-scale lattice metamaterial is designed by the method described in any one of claims 1-9.

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