High-strength energy-absorbing three-dimensional lattice cell element design method based on nesting strategy and application

Abstract

The invention discloses a nesting strategy-based high-strength energy-absorbing three-dimensional lattice cell design method and application, and belongs to the field of structural lightweight design. The method comprises the following steps: constructing a plurality of types of nested cells; carrying out numerical value homogenization calculation on various nested cell elements, establishing a mapping relation between the rigidity coefficient and the relative density of the nested cell elements, and constructing a mapping relation database; generating a space coordinate matrix of all nested cell elements, and obtaining a voxel unit density field and a voxel unit node displacement field through a topological optimization method; in combination with the mapping relation database, the density field and the displacement field, calculating strain energy at each nested cell node to obtain an optimal configuration distribution field of the nested cell three-dimensional lattice structure model; and carrying out heterogeneous fusion on the nested cell elements to obtain a nested cell element three-dimensional lattice structure model for designing or manufacturing aircraft components. According to the method, the self-adaptive distribution of the nested cell element configuration and the relative density in the design domain can be realized, and a complete lightweight design process is established.

Description

Technical Field

[0001] This invention belongs to the field of lightweight structural design technology, specifically relating to a high-strength energy-absorbing three-dimensional lattice cell design method and application based on a nested strategy. Background Technology

[0002] Nested cell design aims to break through the performance boundaries of traditional single-configuration structures. Through advanced spatial topology fusion technology, it organically integrates and optimizes the configuration of various cell units with different deformation mechanisms (such as bending-dominant, tension-dominant, or hybrid modes) in three-dimensional space. This design strategy not only focuses on improving single performance indicators but also emphasizes the synergy and balance of multiple functions such as load-bearing efficiency and energy absorption in the macroscopic structure, thereby constructing a gradient and functional heterogeneous topological organization at the material distribution and mechanical response levels. Nested cell design can effectively adapt to the comprehensive performance requirements of spacecraft under complex load environments (such as extreme temperatures, dynamic impacts, and multiaxial stresses), providing key theoretical support and technical implementation methods for the innovative design and engineering application of next-generation high-performance, multifunctional, and lightweight structures.

[0003] However, existing nested cell designs are mostly limited to simple combinations of classic truss structures such as plates and beams, and lack research on the topological fusion of triple periodic minimum surface (TPMS) type surface cells and truss type cells. In addition, existing design schemes generally rely on Boolean operations in CAD software to complete geometric splicing. Due to the lack of a unified implicit parametric mathematical representation model, the continuity of the nested interface is poor, the design space is limited, and it is difficult to support subsequent efficient gradient optimization design. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a high-strength energy-absorbing three-dimensional lattice cell design method and application based on a nested strategy. This method enables the adaptive distribution of nested cell configurations and their relative densities within the design domain, and establishes a complete cross-scale lightweight design process for fine-grained lattice materials and macroscopic service structures to obtain high-stiffness heterogeneous fused three-dimensional lattices for the design or manufacture of aircraft components.

[0005] This invention provides the following technical solution:

[0006] Firstly, a high-energy-absorbing 3D lattice cell design method based on a nested strategy is provided, including the following steps: Step 1: Based on the implicit expression of the three-period minimal surface lattice, construct several types of nested cells for the nested cell three-dimensional lattice structure model, and use the nested cell three-dimensional lattice structure model as the target model of the aircraft component. Step 2: Perform numerical homogenization calculations on various types of nested cells, establish the mapping relationship between the stiffness coefficient and relative density of nested cells, and construct a mapping relationship database; Step 3: Based on the preset nested cell size and the scale of the nested cell 3D lattice structure model, generate the spatial coordinate matrix of all nested cells, and obtain the voxel unit density field and voxel unit node displacement field through topology optimization method. Step 4: Combining the mapping relationship database with the voxel density field and voxel node displacement field, the optimal configuration distribution field of the nested cell three-dimensional lattice structure model is obtained by calculating the strain energy at each nested cell node. Step 5: Based on the voxel unit density field and the optimal configuration distribution field, heterogeneous fusion of nested cells is performed to obtain a three-dimensional lattice structure model of nested cells. After verification of feasibility, the model is output for use in the design or manufacture of aircraft components.

[0007] Optionally, the nested cell in step 1 includes: an outer shell structure and an inner structure, wherein the inner structure is generated by Boolean intersection of a solid and an inner support structure; both the outer shell structure and the solid adopt PShell type lattice, and the inner support structure adopts P type lattice or IWP type lattice; the ratio of the outer shell structure to the inner structure is 40:60 or 50:50.

[0008] Optionally, the implicit surface equation of the nested cell in step 1 for: ; ; ; in, The implicit equation for the surface of the shell structure. The implicit equations for the surface with an embedded structure. Let be the coordinates of any point in the Cartesian coordinate system. , The characteristic length of nested cells, These represent parameters used to describe the surface shape and surface area of ​​the outer shell structure. It represents the shortest distance to the surface of the outer shell structure and is used to distinguish different areas of the outer shell structure.

[0009] Optionally, step 2 specifically includes: For each type of nested cell, its elasticity matrix is ​​set, and unit strain loads are applied to each node of the nested cell in sequence to obtain the stiffness coefficient. Based on the relative density of the nested cell and the stiffness coefficient of each node of the nested cell, a trinomial fitting is used to obtain the mapping relationship between the stiffness coefficient and the relative density of the nested cell, and a mapping relationship database is constructed.

[0010] Optionally, step 3 specifically includes: The nested cell 3D lattice structure model is divided into hexahedral meshes of voxel elements of a predetermined size. The size of the voxel elements is the same as the size of the nested cells. The voxel element indexes are cyclically marked according to the XYZ directions. The SIMP method is used to perform topology optimization on the nested cell 3D lattice structure model, and the voxel element density field and voxel element node displacement field are output.

[0011] Optionally, step 4 specifically includes: Step 4.1: Calculate the elasticity matrix of various nested cells based on the voxel density field and the mapping relationship between stiffness coefficient and relative density of various nested cells in the mapping relationship database; Step 4.2: Based on the displacement field of voxel element nodes and the elasticity matrix of various nested cells, calculate the strain energy of various nested cells, and select nested cells based on the maximum strain energy to obtain the optimal configuration distribution field of the nested cell three-dimensional lattice structure model.

[0012] Optionally, step 5 specifically includes: Step 5.1: Based on the voxel unit density field and the optimal configuration distribution field, heterogeneously fuse all nested cells using the Gaussian radial basis function as follows: ; The fusion function is: ; in, Let be the coordinates of any point in the Cartesian coordinate system. For the first The diffusion equation for Gaussian radial basis functions of nested cell types. These are parameters used to regulate the transition gradient of the structure as it diffuses from the control point to the surrounding region. For the first The center coordinates of nested cells. To obtain the implicit field function of the entire nested cell-based three-dimensional lattice structure model after fusion, The total number of nested cell types. For the first Implicit surface equations for nested cells. The characteristic length of nested cells, The relative density of nested cells; Step 5.2: Perform performance comparison and verification through finite element simulation of single-configuration gradient structure and heterogeneous fused gradient structure respectively, and finally output the verified nested cell three-dimensional lattice structure model in the form of target source file.

[0013] Secondly, an application of a high-strength energy-absorbing three-dimensional lattice cell design method based on a nested strategy, as described in any one of the first aspects, is to use the output nested cell three-dimensional lattice structure model for the industrial design of aircraft components or to manufacture aircraft components through an additive manufacturing process using the output nested cell three-dimensional lattice structure model.

[0014] Compared with the prior art, the beneficial effects of the present invention are: (1) This invention constructs nested cells with various internal nested configurations, thereby establishing a unified mathematical function representation system for the three-dimensional lattice structure model of nested cells, replacing the traditional nested cell design method that relies on explicit geometric modeling. It not only realizes non-uniform gradient transition, but also deeply couples with gradient-based optimization algorithms, thereby significantly improving the global optimization capability of the three-dimensional lattice model structure. The design method proposed in this invention has certain universality in application. It can expand the degree of freedom of design through the homogenization calculation of nested cells, and can realize the adaptive distribution of nested cell configurations and their relative densities within the design domain. It has a relatively complete theoretical basis, establishes a complete cross-scale lightweight design process for fine-grained lattice materials and macroscopic service structures, and effectively realizes the optimization of structural mechanical performance. It is especially suitable for designing or manufacturing aircraft components.

[0015] (2) The fusion function of this invention adopts a Gaussian radial basis function. The Gaussian radial basis function describes the transition interface equation as a function based on the discrete point coordinates X of the design domain. As long as the center coordinates and configuration of each nested cell in the design domain are determined, the interpolation interface can be generated naturally and efficiently. The relative density of the final generated nested cell three-dimensional lattice structure model can be precisely controlled. It is suitable for situations where the nested cell morphologies are not significantly different during heterogeneous fusion and the requirements for relative density accuracy are high. It avoids the problem in the prior art where the volume fraction is slightly higher than the theoretical value due to the local thickening of the composite TPMS in the transition region caused by the introduction of a density factor. Attached Figure Description

[0016] Figure 1 This is a flowchart of the high-intensity energy-absorbing three-dimensional lattice cell design method based on a nested strategy according to the present invention.

[0017] Figure 2 This is a schematic diagram of the nested cell modeling of the present invention.

[0018] Figure 3 This is the structure type of nested cells in this invention.

[0019] Figure 4 This is a schematic diagram illustrating the application of boundary conditions in the finite element simulation of this invention.

[0020] Figure 5 This is a graph showing the relationship between the stiffness coefficient of the nested cell and the relative density of the present invention.

[0021] Figure 6 This is a flowchart of the nested cell selection based on strain energy according to the present invention.

[0022] Figure 7 The results are finite element simulations before and after optimization of the nested cell structure.

[0023] Figure 8 A comparison chart of performance parameters before and after optimization of the nested cell structure. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and should not be used to limit the scope of protection of the present invention. It should be noted that the term "comprising" and any variations thereof in the specification, claims and the above-mentioned drawings of the present invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products or devices.

[0025] Example 1: like Figure 1 As shown, a high-energy-absorbing 3D lattice cell design method based on a nested strategy includes the following steps: Step 1: Based on the implicit expression of the three-period minimal surface lattice, construct several types of nested cells for the nested cell three-dimensional lattice structure model, and use the nested cell three-dimensional lattice structure model as the target model of the aircraft component. Step 2: Perform numerical homogenization calculations on various types of nested cells, establish the mapping relationship between the stiffness coefficient and relative density of nested cells, and construct a mapping relationship database; Step 3: Based on the preset nested cell size and the scale of the nested cell 3D lattice structure model, generate the spatial coordinate matrix of all nested cells, and obtain the voxel unit density field and voxel unit node displacement field through topology optimization method. Step 4: Combining the mapping relationship database with the voxel density field and voxel node displacement field, the optimal configuration distribution field of the nested cell three-dimensional lattice structure model is obtained by calculating the strain energy at each nested cell node. Step 5: Based on the voxel unit density field and the optimal configuration distribution field, heterogeneous fusion of nested cells is performed to obtain a three-dimensional lattice structure model of nested cells. After verification of feasibility, the model is output for use in the design or manufacture of aircraft components.

[0026] In this embodiment, as Figure 2As shown, the nested cells in step 1 include: an outer shell structure and an inner structure. The inner structure is generated by Boolean intersection of a solid and an inner support structure. Both the outer shell structure and the solid adopt PShell type lattice, and the inner support structure adopts P type lattice or IWP type lattice. The ratio of the outer shell structure to the inner structure is 40:60 or 50:50, that is, the configuration of the inner support structure (P type or IWP type) can be changed by changing the inner support structure function, and the ratio of the inner and outer structures can be changed by changing the ratio coefficient of the inner structure to the outer shell structure.

[0027] The implicit surface equation of the nested cells in step 1 for: ; The size of the opening in the shell structure can be controlled by redefining the original opening diameter using shape parameters: ; ; in, The implicit equation for the surface of the shell structure. The implicit equations for the surface with an embedded structure. Let be the coordinates of any point in the Cartesian coordinate system. This indicates that nested cells are generated by Boolean intersection of an outer shell structure and an inner structure. , The characteristic length of nested cells, These represent parameters used to describe the surface shape and surface area of ​​the outer shell structure. This represents the shortest distance to the surface of the outer shell structure, used to distinguish different areas of the outer shell structure, i.e., when... Using negative values ​​reduces the opening diameter but causes the entire surface to shift. To minimize the shift outside the opening region, a cube volume distance value is used. (Represents the shortest distance to the cube surface, used to distinguish different regions of a unit cell) to control value.

[0028] ; in, It is an internal support structure (P-type or IWP-type). and They are internal support structure and solid. The implicit surface equation. This indicates that the embedded structure is generated by Boolean intersection of the inner support structure and the solid.

[0029] In this implementation, the PShell type lattice, P type lattice, and IWP type lattice are all TPMS three-dimensional lattice models, and the expression of the implicit function is: Equation of P-type lattice surface: ; IWP type lattice surface equation: ; PShell type lattice surface equation: ; In the formula, , , , The characteristic length of the nested cell is determined by the level set constant. Controlling the relative density variation of the lattice structure; Let be the coordinates of any point in the Cartesian coordinate system.

[0030] In this embodiment, a specific example of a nested cell configuration is given, such as... Figure 3 As shown, the internal support structure is selected from two types: Primitive and IWP. The opening size is divided into two types: small opening and large opening. The ratio of the inner and outer structure is 40:60 and 50:50. A total of 8 nested cells are established, namely: S_Pp 40:60, S_Pp 50:50, S_Pw 40:60, S_Pw 50:50, B_Pp 40:60, B_Pp 50:50, B_Pw 40:60, B_Pw 50:50.

[0031] In this embodiment, step 2 specifically includes: Step 2.1: Set the elasticity matrix for each type of nested cell.

[0032] Due to the symmetry of orthogonal systems, the number of unknown stiffness coefficients in the fourth-order stiffness matrix is ​​reduced from 81 to 21. This is because nested cells possess cubic symmetry. , , This can further simplify the unknown stiffness coefficients, at which point the elastic matrix of the nested cells... It contains only 12 non-zero terms: ; Step 2.2: Apply unit strain loads to each node of the nested cell sequentially to obtain the stiffness coefficient.

[0033] Apply unit strain loads sequentially, meaning that only one strain component is 1 at a time, and the rest are 0, as shown below. Figure 4 As shown. Under these conditions, the corresponding stiffness coefficients in the elasticity matrix are numerically equal to their corresponding macroscopic stress components, and can be obtained by extracting the support reactions of the corresponding surfaces through finite element analysis: ; Step 2.3: Based on the relative density of nested cells and the stiffness coefficients of each node of the nested cells, the lattice stiffness coefficients of the nested cells are... With relative density The mapping relationship between the stiffness coefficients and relative density of the array elements was obtained by fitting the finite element analysis results with a cubic polynomial, as follows: Figure 5 As shown, construct a mapping relationship database.

[0034] ; in, , , and These represent the fitting coefficients.

[0035] Each type of nested cell is assigned a unique number, which can be Arabic numerals, English letters, or a combination thereof. In the heterogeneous fused matrix, the number of each nested cell type is unique, and the total number of numbers depends on the number of different nested cell categories contained therein, establishing a mapping relationship database.

[0036] In this embodiment, step 3 specifically includes: Step 3.1: Divide the nested cell 3D lattice structure model into a hexahedral mesh of voxel units of a predetermined size. The size of the voxel unit is the same as the size of the nested cell. The voxel unit index is cyclically marked according to the XYZ direction.

[0037] The principle for calculating and generating the nested cell spatial coordinate matrix is ​​as follows: The nested cell 3D lattice structure model is the same as the TPMS lattice structure, exhibiting periodic arrangement characteristics. If the center of the overall model structure is taken as the origin... Given the scale and unit size of the nested cell 3D lattice structure model, the spatial coordinates of the center point of each nested cell can be calculated one by one. These center coordinates together constitute the unit spatial coordinate matrix, which essentially describes the specific spatial position of each unit in the overall lattice structure.

[0038] The specific calculation process is as follows: First, calculate the center coordinates of the nested cells using the following formula: ; in, These are the center coordinates of nested cells within the design domain. , and These respectively represent the current nested cells in Spatial indexes in three directions (e.g.) In the lattice structure The first direction (nested cells) , and These respectively represent the lattice structure in The number of nested cells in the direction, The characteristic length of the nested cell.

[0039] The element space coordinate matrix is ​​calculated using the following formula: ; in Constructing a unit space coordinate matrix, It means along Direction index, for For each value of , the matrix contains all values ​​in the above formula that satisfy the corresponding... The elements of the coordinates. For example, when At that time, that is Includes all Coordinates are The set of elements.

[0040] Step 3.2: The SIMP method is used to perform topology optimization on the nested cell 3D lattice structure model, and the voxel unit density field and voxel unit node displacement field are output.

[0041] Specifically, based on the aforementioned spatial coordinate matrix of the nested cell center points, voxelization is performed using the cantilever beam as the optimization object, and the voxel unit size corresponds to the unit size of the lattice structure. After applying boundary and load conditions, topology optimization analysis is performed, and the specific objective equation for optimization is as follows: The objective equation for optimization is as follows: ; ; ; ; ; In the formula, the objective function This represents structural flexibility, with the minimum flexibility as the optimization objective, i.e., maximum stiffness. For nodal force vectors, Representing the nodal displacement vector, obtained by solving the finite element equilibrium equations. get, Represents the overall stiffness matrix; This represents the number of discrete elements in the topology optimization design domain. The normalized density field for each voxel unit; This represents the volume limit of the material in the topology optimization design domain, set to 0.35. Let be the volume vector of each voxel unit. and These represent the lower and upper bounds of the voxel element density field, respectively. In the numerical implementation, the optimization problem is solved using the OC algorithm, and the sensitivity derived from the adjoint method is used as the input condition. Finally, the voxel element density field and element nodal displacement field are output when the optimal solution is obtained.

[0042] In this embodiment, as Figure 6 As shown, step 4 specifically includes: Step 4.1: Calculate the elasticity matrix of various nested cells based on the voxel density field and the mapping relationship between stiffness coefficient and relative density of various nested cells in the mapping relationship database.

[0043] No. Elasticity matrix of nested cells It can be based on the results of nested cell numerical homogenization and the density of the currently numbered voxel units The calculated expression is as follows: ; Step 4.2: Based on the displacement field of voxel element nodes and the elasticity matrix of various nested cells, calculate the strain energy of various nested cells, and select nested cells based on the maximum strain energy to obtain the optimal configuration distribution field of the nested cell three-dimensional lattice structure model.

[0044] Based on the elastic matrix of nested cell lattices The effective stiffness matrix of the element is calculated. : ; In the formula, Represents the design domain element; This represents the transpose of the element strain matrix; Get nested cell node displacements The strain energy at the nested cell node is calculated using the following formula. : ; In the formula, This represents the transpose matrix of the element node displacements.

[0045] In this embodiment, step 5 specifically includes: Step 5.1: Based on the voxel unit density field and the optimal configuration distribution field, heterogeneously fuse all nested cells using the Gaussian radial basis function as follows: ; The fusion function is: ; in, Let be the coordinates of any point in the Cartesian coordinate system. For the first The diffusion equation for Gaussian radial basis functions of nested cell types. These are parameters used to regulate the transition gradient of the structure as it diffuses from the control point to the surrounding region. For the first The center coordinates of nested cells. To obtain the implicit field function of the entire nested cell-based three-dimensional lattice structure model after fusion, The total number of nested cell types. For the first Implicit surface equations for nested cells. The characteristic length of nested cells, The relative density of nested cells.

[0046] The fusion function of this invention uses a Gaussian radial basis function (RBF), which has the advantage of describing the transition interface equation as a function based on the discrete point coordinates X of the design domain. By determining the center coordinates and configuration of each nested cell in the design domain, the interpolated interface can be generated naturally and efficiently. The relative density of the final generated nested cell 3D lattice structure model can be precisely controlled. This is suitable for heterogeneous fusion where the nested cell morphologies are similar and high precision in relative density is required. It avoids the problem in existing technologies where the introduction of a density factor to locally thicken the composite TPMS in the transition region results in a volume fraction slightly higher than the theoretical value.

[0047] Step 5.2: Perform performance comparison and verification through finite element simulation of single-configuration gradient structure and heterogeneous fused gradient structure respectively, and finally output the verified nested cell three-dimensional lattice structure model in the form of target source file.

[0048] By combining the closed bounding box reconstruction algorithm, the optimized design field is transformed into a manufacturable geometric model and verified. The verified nested cell 3D lattice structure model is output as a target model source file. In subsequent industrial applications, the verified nested cell 3D lattice structure model can be used as the target model for subsequent industrial design and manufacturing.

[0049] After heterogeneous fusion was completed, the resulting heterogeneous fused structure was compared with the structure under the single configuration using finite element simulation. The comparisons were made between four different structures: the existing uniform P-shell structure, the gradient P-shell structure, the optimized nested cell structure of this invention (small outer shell opening), and the optimized nested cell heterogeneous structure (large outer shell opening). Figure 7 The finite element simulation results of four structures are presented. Two evaluation indicators, strength and energy absorption, are selected for quantitative analysis of the simulation results. Figure 8 In the diagram, (a) and (c) represent the strength comparison diagrams of the small-opening shell structure and the large-opening shell structure compared to the gradient P-shell structure and the uniform P-shell structure, respectively. Figure 8 In the diagram, (b) and (d) represent the energy absorption comparison between the small-opening shell structure and the large-opening shell structure, compared to the gradient P-shell structure and the uniform P-shell structure, respectively; Figure 8 As shown, the small-shell opening structure achieves a significant improvement of 15.5% and 32.8% in structural strength compared to the gradient P-shell structure and the uniform P-shell structure, respectively; its energy absorption capacity shows an even more considerable improvement, reaching 20.8% and 67.9%, respectively. The large-shell opening structure, compared to the gradient P-shell structure and the uniform P-shell structure, achieves a significant improvement of 13.8% and 31.1% in structural strength compared to the gradient P-shell structure and the uniform P-shell structure, respectively; its energy absorption capacity shows an even more considerable improvement, reaching 18.5% and 65.6%, respectively, verifying the effectiveness of the nested cell lattice modeling and strain energy-driven multi-scale design method.

[0050] Example 2: An application of a high-strength energy-absorbing three-dimensional lattice cell design method based on a nested strategy, as described in any one of Embodiments 1, allows the output nested cell three-dimensional lattice structure model to be used for the industrial design of aircraft components, or the output nested cell three-dimensional lattice structure model to be manufactured into aircraft components through an additive manufacturing process.

[0051] In industrial applications, additive manufacturing equipment (not shown in the figure) can be connected to the output end of a 3D lattice model. The validated 3D lattice model is used as the target model, imported into the additive manufacturing equipment, and preset processing requirements are added. The additive manufacturing equipment then executes the additive manufacturing process according to the configuration and processing requirements of the target model. The additive manufacturing equipment and process are based on existing technologies and will not be elaborated upon here. The above is merely one feasible application scenario and is not intended to limit the application of the technical solution of this invention.

[0052] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section. Those skilled in the art will clearly understand that the technologies in the embodiments of this invention can be implemented using software plus necessary general-purpose hardware platforms. Based on this understanding, the technical solutions in the embodiments of this invention, in essence or the parts that contribute to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or certain parts of the embodiments of this invention.

[0053] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A high-intensity energy-absorbing three-dimensional lattice cell design method based on a nested strategy, characterized in that, Includes the following steps: Step 1: Based on the implicit expression of the three-period minimal surface lattice, construct several types of nested cells for the nested cell three-dimensional lattice structure model, and use the nested cell three-dimensional lattice structure model as the target model of the aircraft component. Step 2: Perform numerical homogenization calculations on various types of nested cells, establish the mapping relationship between the stiffness coefficient and relative density of nested cells, and construct a mapping relationship database; Step 3: Based on the preset nested cell size and the scale of the nested cell 3D lattice structure model, generate the spatial coordinate matrix of all nested cells, and obtain the voxel unit density field and voxel unit node displacement field through topology optimization method. Step 4: Combining the mapping relationship database with the voxel density field and voxel node displacement field, the optimal configuration distribution field of the nested cell three-dimensional lattice structure model is obtained by calculating the strain energy at each nested cell node. Step 5: Based on the voxel unit density field and the optimal configuration distribution field, heterogeneous fusion of nested cells is performed to obtain a three-dimensional lattice structure model of nested cells. After verification of feasibility, the model is output for use in the design or manufacture of aircraft components.

2. The high-intensity energy-absorbing three-dimensional lattice cell design method based on a nested strategy according to claim 1, characterized in that, The nested cells in step 1 include: an outer shell structure and an inner structure. The inner structure is generated by Boolean intersection of a solid and an inner support structure. Both the outer shell structure and the solid adopt PShell type lattice, and the inner support structure adopts P type lattice or IWP type lattice. The ratio of the outer shell structure to the inner structure is 40:60 or 50:

50.

3. The high-intensity energy-absorbing three-dimensional lattice cell design method based on a nested strategy according to claim 1, characterized in that, The implicit surface equation of the nested cells in step 1 for: ； ； ； in, The implicit equation for the surface of the shell structure. The implicit equations for the surface with an embedded structure. Let be the coordinates of any point in the Cartesian coordinate system. , The characteristic length of nested cells, These represent parameters used to describe the surface shape and surface area of ​​the outer shell structure. It represents the shortest distance to the surface of the outer shell structure and is used to distinguish different areas of the outer shell structure.

4. The high-intensity energy-absorbing three-dimensional lattice cell design method based on a nested strategy according to claim 1, characterized in that, Step 2 specifically includes: For each type of nested cell, its elasticity matrix is ​​set, and unit strain loads are applied to each node of the nested cell in sequence to obtain the stiffness coefficient. Based on the relative density of the nested cell and the stiffness coefficient of each node of the nested cell, a trinomial fitting is used to obtain the mapping relationship between the stiffness coefficient and the relative density of the nested cell, and a mapping relationship database is constructed.

5. The high-intensity energy-absorbing three-dimensional lattice cell design method based on a nested strategy according to claim 1, characterized in that, Step 3 specifically includes: The nested cell 3D lattice structure model is divided into hexahedral meshes of voxel elements of a predetermined size. The size of the voxel elements is the same as the size of the nested cells. The voxel element indexes are cyclically marked according to the XYZ directions. The SIMP method is used to perform topology optimization on the nested cell 3D lattice structure model, and the voxel element density field and voxel element node displacement field are output.

6. The high-intensity energy-absorbing three-dimensional lattice cell design method based on a nested strategy according to claim 1, characterized in that, Step 4 specifically includes: Step 4.1: Calculate the elasticity matrix of various nested cells based on the voxel density field and the mapping relationship between stiffness coefficient and relative density of various nested cells in the mapping relationship database; Step 4.2: Based on the displacement field of voxel element nodes and the elasticity matrix of various nested cells, calculate the strain energy of various nested cells, and select nested cells based on the maximum strain energy to obtain the optimal configuration distribution field of the nested cell three-dimensional lattice structure model.

7. The high-strength energy-absorbing three-dimensional lattice cell design method based on a nested strategy according to claim 1, characterized in that, Step 5 specifically includes: Step 5.1: Based on the voxel unit density field and the optimal configuration distribution field, heterogeneously fuse all nested cells using the Gaussian radial basis function as follows: ； The fusion function is: ； in, Let be the coordinates of any point in the Cartesian coordinate system. For the first The diffusion equation for Gaussian radial basis functions of nested cell types. These are parameters used to regulate the transition gradient of the structure as it diffuses from the control point to the surrounding region. For the first The center coordinates of nested cells. To obtain the implicit field function of the entire nested cell-based three-dimensional lattice structure model after fusion, The total number of nested cell types. For the first Implicit surface equations for nested cells. The characteristic length of nested cells, The relative density of nested cells; Step 5.2: Perform performance comparison and verification through finite element simulation of single-configuration gradient structure and heterogeneous fused gradient structure respectively, and finally output the verified nested cell three-dimensional lattice structure model in the form of target source file.

8. An application of a high-strength energy-absorbing three-dimensional lattice cell design method based on a nested strategy according to any one of claims 1-7, characterized in that, The output nested cell 3D lattice structure model can be used for the industrial design of aircraft components, or the output nested cell 3D lattice structure model can be used to manufacture aircraft components through additive manufacturing processes.

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