A load-oriented honeycomb porous structure, material and design method thereof

Abstract

The present invention belongs to the field of porous materials, and specifically relates to a load-oriented honeycomb porous structure, a honeycomb porous material with a corresponding structure, and a design method thereof. The designed load-oriented honeycomb porous structure includes three spatial configurations: compression-first, shear-first, and torsion-first. The first two honeycomb porous structures are composed of an external regular hexagonal frame and an internal mesh reinforcement with a specific shape and spatial distribution. The cross-sections of the mesh reinforcements of the two are both centrally symmetrical. The torsion-first honeycomb porous structure is characterized by locally thickening or thinning the inner layer of the hexagonal outer frame so that the thickness of the annular honeycomb holes is distributed in a specific shape. The design method of the load-oriented honeycomb porous structure provided by the present invention can customize the design of a honeycomb porous structure with specific performance according to the needs of the application scenario. This method is a universal digital method with powerful performance and can design the required porous material at low cost.

Description

Technical Field

[0001] The present invention belongs to the field of porous materials, and in particular relates to a load-oriented honeycomb porous structure, a honeycomb porous material with a corresponding structure, and a design method thereof. Background Art

[0002] In recent years, lightweight materials and structures have become increasingly popular in product design. This is because in fields such as aerospace, biomedicine, petrochemicals, and industrial manufacturing, lightweight materials often mean reduced resource utilization, lower energy consumption, and enhanced environmental protection. Some lightweight materials or lightweight structural designs that have entered the application stage not only maintain excellent mechanical properties but also offer energy-saving and environmentally friendly properties, meeting the requirements of sustainable development.

[0003] As a type of lightweight structure, porous structure not only has the properties of weight reduction, cushioning, heat insulation, thermal insulation, and noise reduction, but also has the characteristics of high specific strength, high specific stiffness, and high energy absorption. It is an engineering material with integrated form and properties. The ultra-high degree of design freedom and super-strong performance controllability make porous structures show great application prospects in the context of the rapid development of the manufacturing industry. In the past, due to the limitations of traditional mechanical processing and manufacturing technology, the manufacturing process of porous structures, which are materials or structures with complex spatial geometric features, was extremely difficult and the production cost was high. This made it difficult to reflect the great advantages of porous structures and restricted the application of such structures. However, with the rapid development of additive manufacturing (AM) technology, a large number of geometric features that are difficult to obtain through ordinary machining methods can be quickly mass-produced through additive manufacturing technology; this also made the advantages of porous structures gradually stand out.

[0004] The existing optimization design of honeycomb porous structures mostly focuses on external reinforcement or filling of honeycomb porous structures, or inlaying other structural materials on the base material to create composite honeycomb porous materials. However, innovative reinforcement of the internal space structure of honeycomb porous structures is rarely involved. The main problems in the field of porous material design are in the following two aspects: First, the design of existing porous materials is often optimized for a single function, the comprehensive mechanical properties of the materials are insufficient, and the adaptability to different application scenarios is relatively poor, making it difficult to meet market demand. Second, the current optimization design method of honeycomb porous structures is relatively complex, with high material and time costs, and low utilization of structural materials, which does not conform to the concept of green and environmentally friendly development. Summary of the Invention

[0005] In order to solve the problems of poor performance and single function of existing porous materials, low design efficiency and high R&D cost of new materials, the present invention provides a load-oriented honeycomb porous structure, material and design method thereof.

[0006] The present invention is achieved by adopting the following technical solutions:

[0007] A load-oriented honeycomb porous structure includes three spatial configurations: compression-first, shear-first, and torsion-first. The compression-first type refers to a basic honeycomb unit configuration of a honeycomb porous structure with higher compressive strength; the shear-first type refers to a basic honeycomb unit configuration of a honeycomb porous structure with better resistance to shear stress; and the torsion-first type refers to a basic honeycomb unit configuration of a honeycomb porous structure with higher torsional strength.

[0008] According to cross-sectional analysis, the basic unit of the compression-first honeycomb porous structure consists of a regular hexagonal outer frame and an internal reinforcement structure. For ease of description: define the side length of the hexagonal outer frame of the honeycomb unit as L and the wall thickness as t1; number the six sides of the outer frame in a clockwise direction from 1 to 6, then:

[0009] The reinforcing rib structure includes a first reinforcing portion and a second reinforcing portion symmetrically distributed on both sides of the inner portion of the outer frame. The first reinforcing portion includes a first V-rod composed of two long rods of equal length, and a second V-rod composed of two short rods of equal length. The two ends of the first V-rod are respectively connected to the midpoints of the inner sides of sides 2 and 6. The angle of the first V-rod is 140° and the vertex of the angle is close to side 1. The second V-rod crosses the first V-rod in an X shape, and the ends of the two short rods are connected to the inner side of side 1, and the angle between adjacent long rods and short rods is 70°. In addition, the inner side of the angle between the two short rods of the compression-priority honeycomb porous structure of the present invention also includes an arc segment with an opening facing outward with an R=0.86L.

[0010] Correspondingly, the second reinforcement portion in the compression-priority honeycomb porous structure of the present invention is connected to the inner walls of sides 3, 4, and 5, and the structure of the second reinforcement portion is similar to that of the first reinforcement portion; and the cross-section of the compression-priority honeycomb porous structure is actually a strictly centrally symmetrical figure.

[0011] As a further improvement of the present invention, in the compression-prioritized honeycomb porous structure, the wall thickness of the internal reinforcing rib structure is uniform; and the wall thickness of the external outer frame is twice the wall thickness of the internal reinforcing rib structure.

[0012] In the solution provided by the present invention, according to cross-sectional analysis, the basic unit of the shear-preferential honeycomb porous structure includes a regular hexagonal outer frame and an internal reinforcing rib structure. Similarly, the outer frame side length is defined as L, the wall thickness is defined as t2; the outer frame sides are numbered 1-6 in a clockwise direction; then:

[0013] The reinforcing rib structure inside the shear-preferential honeycomb porous structure includes: a long rod part, a short rod part, and a support rod part. Among them, the two long rods are equal in length and cross each other, and the four endpoints of the long rods are respectively connected to the inner walls of sides 2, 3, 5, and 6. The two support rods are also equal in length, and one end of the two support rods is vertically connected to the inner side of sides 1 and 4. There are four short rods in total, and every two short rods of equal length form a third V-rod with an angle of 140°; the vertices of the angles in the two third V-rods are respectively connected to the other ends of the two support rods; the two ends of the third V-rod are respectively connected to the two adjacent long rods. In addition, in the shear-preferential honeycomb porous structure, at the intersection of the long rod and the short rod, the interior of the acute angle side also includes an arc segment with R=0.04L.

[0014] As a further improvement of the present invention, in the shear-priority honeycomb porous structure, the support rod portion and the section from the intersection of the short rod and the long rod extending to the outer frame are all thickened sections, and the wall thickness of the remaining parts except the thickened section is uniform and relatively thin.

[0015] In the solution provided by the present invention, according to cross-sectional analysis, the outer contour of the basic unit of the torsion-preferred honeycomb porous structure is a regular hexagon, and the internal hollow structure is a symmetrical olive shape. The edges of the outer contour are defined as 1-6 in clockwise order, then:

[0016] The two continuous sections extending from the midpoint of side 2 to the midpoint of side 3, and from the midpoint of side 5 to the midpoint of side 6, are both sections with uniform wall thickness. The remaining two sections are sections with non-uniform wall thickness. The inner wall of the sections from the midpoint of side 3 to the midpoint of side 5, and from the midpoint of side 6 to the midpoint of side 2, is a continuous inward-concave arc segment with an R of 0.86L.

[0017] The present invention also includes a load-oriented honeycomb porous material, which is composed of a plurality of honeycomb units arranged in an array in a plane or three-dimensional space. The honeycomb units adopt one or more of the aforementioned load-oriented honeycomb porous structures.

[0018] As a further improvement of the present invention, the load-oriented honeycomb porous material provided by the present invention is processed by 3D printing technology.

[0019] The present invention also includes a method for designing a load-oriented honeycomb porous material, which is used to design the load-oriented honeycomb porous material as described above; the design method comprises the following steps:

[0020] S1: Mathematical model of a typical honeycomb unit that constructs a regular hexagonal framework.

[0021] S2: Use the SIMP variable density topology optimization strategy to perform topology optimization analysis on ordinary honeycomb units.

[0022] The topology optimization model used is as follows:

[0023]

[0024] In the above formula, x is the design variable; x i is the cell density; x min and x max are the minimum and maximum unit density in the design area respectively; C(x) is the flexibility matrix of the design area; F is the load matrix of the entire structure; U is the displacement matrix of the entire structure; K is the stiffness matrix of the entire structure; k0 represents the stiffness matrix of the specified design area; V is the volume of the optimized structure; V0 is the volume of the specified design area, v i is the volume of the unit; μ is the volume ratio of the structure after topology optimization within the specified design area to the original structure within the design area; n is the total number of units in the mesh; and p is the preset model penalty coefficient.

[0025] S3: Based on the result data after topology optimization analysis, curve fitting is performed on the model of the structure to obtain the outline of the basic contour of the new honeycomb unit body.

[0026] S4: Simplify the outline of the basic contour of the optimized new honeycomb unit body and measure the key parameters used to characterize the structural characteristics of the honeycomb unit.

[0027] S5: Reconstruct a simplified model of the new honeycomb unit based on the key structural parameters measured in the previous step, and generate a three-dimensional model of the corresponding honeycomb porous structure.

[0028] S6: Utilize the finite element analysis method to verify the optimized design of the novel honeycomb unit body, simulate the stress, strain, and deformation of different structures under the same load conditions, and obtain the comprehensive mechanical properties and energy absorption performance data of the optimized novel honeycomb unit body.

[0029] S7: cyclically execute steps S2-S6 until the spatial configuration of the honeycomb porous structure that meets the performance requirements is determined, and the honeycomb porous material required for the corresponding spatial configuration is designed; finally, sample trial production and performance verification are carried out.

[0030] As a further improvement of the present invention, in step S1, the mathematical model of the typical honeycomb unit is as follows: the wall thickness of the typical honeycomb unit body is defined as t, the side length is a, the diameter of the inscribed circle of the inner hole is d, the cross-section of the typical honeycomb unit body is a regular hexagon, and the hole size and shape are mainly determined by d.

[0031] As a further improvement of the present invention, in step S2, the topology optimization analysis process uses unit density as a design variable, maximizes unit stiffness as an optimization goal, and uses porosity as a constraint condition.

[0032] The technical solution provided by the present invention has the following beneficial effects:

[0033] The load-oriented honeycomb porous structure provided by this invention improves upon the classic honeycomb porous structure to meet diverse needs. Reinforcing ribs of varying shapes and distributions are added to the outer frame, significantly enhancing the structure's resistance to compression, shear, and torsion. This allows the material to maintain its low density while also possessing superior mechanical properties, meeting the requirements for cushioning, thermal insulation, heat preservation, and noise reduction in various application scenarios.

[0034] The load-oriented honeycomb porous structure designed by this invention exhibits superior comprehensive mechanical properties and energy absorption performance compared to traditional honeycomb structures. Furthermore, at a macroscopic level, this solution can enhance the material's application value in aerospace, machinery manufacturing, petrochemicals, and other fields, meeting the urgent demand for high-performance, lightweight materials in the engineering field. At a microscopic level, the technical solution provided by this invention also increases the specific surface area compared to traditional honeycomb porous structures, theoretically enabling stronger cell adsorption performance and enhancing its application in the biomedical field.

[0035] The present invention also provides a design method for honeycomb multicellular structures with different performance advantages. This design method overcomes the shortcomings of traditional honeycomb multicellular structures, which have limited functionality, by creating a new honeycomb multicellular structure that is adaptive to different load conditions. This design method enables on-demand supply, features an efficient and fast design process, simple and easy-to-understand operation methods, and a wide range of functional types. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic structural diagram of the compression-first honeycomb porous structure designed in Example 1 of the present invention.

[0037] Figure 2 This is a schematic structural diagram of the shear-preferred honeycomb porous structure designed in Example 1 of the present invention.

[0038] Figure 3 Schematic diagram of the structure of the torsion-first honeycomb porous structure designed in Example 1 of the present invention.

[0039] Figure 4 This is a flow chart of the steps of the design method of the load-oriented honeycomb porous structure provided in Example 1 of the present invention.

[0040] Figure 5 This is the mathematical model of the ordinary regular hexagonal honeycomb unit body in Example 1 of the present invention.

[0041] Figure 6This is a plan view of the porous structure formed by an array of ordinary honeycomb units in Example 1 of the present invention.

[0042] Figure 7 It is a three-dimensional simplified module of the common honeycomb porous structure in Example 1 of the present invention.

[0043] Figure 8 This is the finite element model of the outer frame of the honeycomb porous unit constructed in the priority design stage in Example 1 of the present invention.

[0044] Figure 9 These are the load conditions and boundary conditions of the compression-prioritized honeycomb porous structure unit in the design phase of Example 1 of the present invention.

[0045] Figure 10 These are the load conditions and boundary conditions of the shear-preferred honeycomb porous structure unit in the design stage in Example 1 of the present invention.

[0046] Figure 11 These are the load conditions and boundary conditions of the torsion-first honeycomb porous structure unit in the design stage in Example 1 of the present invention.

[0047] Figure 12 This is the outline of the compression-first honeycomb porous structure optimized in Example 1 of the present invention.

[0048] Figure 13 This is the outline of the shear-preferred honeycomb porous structure optimized in Example 1 of the present invention.

[0049] Figure 14 This is the outline of the torsion-first honeycomb porous structure optimized in Example 1 of the present invention.

[0050] Figure 15 This is a plan view of the compression-first honeycomb porous structure designed in Example 1 of the present invention.

[0051] Figure 16 This is a simplified three-dimensional model of the compression-first honeycomb porous structure designed in Example 1 of the present invention.

[0052] Figure 17 This is a plan view of the shear-preferential honeycomb porous structure designed in Example 1 of the present invention.

[0053] Figure 18 This is a simplified three-dimensional model of the shear-preferred honeycomb porous structure designed in Example 1 of the present invention.

[0054] Figure 19 This is a plan view of the twist-first honeycomb porous structure designed in Example 1 of the present invention.

[0055] Figure 20This is a simplified three-dimensional model of the torsion-preferred honeycomb porous structure designed in Example 1 of the present invention.

[0056] Figure 21 Figures 2 and 3 show stress-strain curves of a common honeycomb porous structure and three improved honeycomb porous structures designed in the present invention in a quasi-static compression test in a performance test experiment. DETAILED DESCRIPTION

[0057] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0058] Example 1

[0059] The present embodiment provides a load-oriented honeycomb porous structure, which is intended to improve the mechanical properties of traditional honeycomb porous structures. Compared with conventional structures, the solution of this embodiment can significantly improve the energy absorption performance of the material while ensuring the same material quality and porosity; and reduce the difficulty of manufacturing the material, improve production efficiency, and reduce production costs. This embodiment provides three spatial configurations with different performances for different application scenarios. Specifically, there are three spatial configurations: compression-first, shear-first, and torsion-first. Among them, the compression-first type refers to a basic honeycomb unit configuration of a honeycomb porous structure with higher compressive strength; the shear-first type refers to a basic honeycomb unit configuration of a honeycomb porous structure with better resistance to shear stress; and the torsion-first type refers to a basic honeycomb unit configuration of a honeycomb porous structure with higher torsional strength.

[0060] 1. Compression priority

[0061] like Figure 1 As shown in the figure, according to cross-sectional analysis, the basic unit of the compression-first honeycomb porous structure consists of a regular hexagonal outer frame and an internal reinforcing rib structure. For ease of description: define the side length of the hexagonal outer frame of the honeycomb unit as L and the wall thickness as t1; number the six sides of the outer frame in a clockwise direction from 1 to 6, then:

[0062] The reinforcing rib structure includes a first reinforcing portion and a second reinforcing portion symmetrically distributed on both sides of the inner portion of the outer frame. The first reinforcing portion includes a first V-rod composed of two long rods of equal length, and a second V-rod composed of two short rods of equal length. The two ends of the first V-rod are respectively connected to the midpoints of the inner sides of sides 2 and 6. The angle of the first V-rod is 140° and the vertex of the angle is close to side 1. The second V-rod crosses the first V-rod in an X shape, and the ends of the two short rods are connected to the inner side of side 1, and the angle between adjacent long rods and short rods is 70°. In addition, the inner side of the angle between the two short rods of the compression-priority honeycomb porous structure of the present invention also includes an arc segment with an opening facing outward with an R=0.11L.

[0063] Correspondingly, the second reinforcement portion of the compression-first honeycomb porous structure provided in this embodiment is connected to the inner walls of sides 3, 4, and 5, and the structure of the second reinforcement portion is similar to that of the first reinforcement portion; and the cross-section of the compression-first honeycomb porous structure is actually a strictly centrally symmetrical figure. Figure 1 In the figure, straight lines AA and BB are two mutually perpendicular symmetry axes of the cross-section figure.

[0064] In particular, in order to ensure material strength while reducing material quality, in this embodiment, in the compression-priority honeycomb porous structure, the wall thickness of the internal reinforcing rib structure is designed to be uniform and relatively thin; the wall thickness of the external frame is twice the wall thickness of the internal reinforcing rib structure.

[0065] 2. Shear priority type

[0066] In the solution provided in this embodiment, Figure 2 As shown in the figure, according to the cross-sectional analysis, the basic unit of the shear-preferred honeycomb porous structure consists of a regular hexagonal outer frame and an internal reinforcing rib structure. Similarly, the side length of the outer frame is defined as L, and the wall thickness is defined as t2; the sides of the outer frame are numbered 1-6 in a clockwise direction; then:

[0067] The reinforcing rib structure inside the shear-preferential honeycomb porous structure includes: a long rod part, a short rod part, and a support rod part. Among them, the two long rods are equal in length and cross each other, and the four endpoints of the long rods are respectively connected to the inner walls of sides 2, 3, 5, and 6. The two support rods are also equal in length, and one end of the two support rods is vertically connected to the inner side of sides 1 and 4. There are four short rods in total, and every two short rods of equal length form a third V-rod with an angle of 140°; the vertices of the angles in the two third V-rods are respectively connected to the other ends of the two support rods; the two ends of the third V-rod are respectively connected to the two adjacent long rods. In addition, in the shear-preferential honeycomb porous structure, at the intersection of the long rod and the short rod, the interior of the acute angle side also includes an arc segment with R=0.04L.

[0068] from Figure 2It can be seen that in the shear-preferred honeycomb porous structure, the support rod part and the section where the intersection of the short rod and the long rod extends to the outer frame are all thickened sections. Except for the thickened section, the wall thickness of the rest of the section is uniform and relatively thin. At the same time, the internal reinforcement ribs divide the outer frame into 8 cavities of different sizes. Each cavity is a symmetrical quadrilateral and symmetrical in pairs. Figure 2 The cross section of the shear-preferred honeycomb porous structure is actually a strictly centrosymmetrical figure. In the figure, straight lines CC and DD are the two mutually perpendicular symmetry axes of the cross section.

[0069] 3. Torsion priority type

[0070] In the solution provided in this embodiment, Figure 3 As shown in the figure, according to the cross-sectional analysis, the outer contour of the basic unit of the torsion-preferred honeycomb porous structure is a regular hexagon, and the internal hollow structure is a symmetrical olive shape. The edges in the outer contour are divided into numbers 1-6 in clockwise order, then:

[0071] The inner edge of the torsion-preferential honeycomb structure in this embodiment resembles an olive, a perfectly regular shape. The center of the shape is formed by two symmetrical arcs, with sharp ends formed by straight lines. The curved segments are parallel to the outer frame, ensuring a uniform wall thickness. The arc segments exhibit uneven but regularly distributed wall thickness.

[0072] Specifically, the two continuous sections extending from the midpoint of side 2 to the midpoint of side 3, and from the midpoint of side 5 to the midpoint of side 6, are both sections with uniform wall thickness. The remaining two sections are sections with non-uniform wall thickness. Furthermore, the inner wall of the sections from the midpoint of side 3 to the midpoint of side 5, and from the midpoint of side 6 to the midpoint of side 2, are both continuous inward-concave arc sections with R = 0.86L.

[0073] The above content provides the mathematical representations corresponding to the three types of load-oriented honeycomb porous structures with different performance designed in this embodiment. It should be emphasized that: in the three types of load-oriented honeycomb porous structures provided in this embodiment, shape is the main feature that needs to be protected in the structure, and size is relatively secondary. Scaling the same structure proportionally can produce material properties with similar effects in different products or materials. For example, the honeycomb porous structure in this embodiment can be used to process large-sized profiles of corresponding shapes; the honeycomb porous structure can also be used to process plates or filter materials with a large number of specific microstructures, and so on.

[0074] In the design process of the above three honeycomb porous structures provided in this embodiment, a new design method combining three-dimensional modeling, topology optimization analysis and finite element analysis is adopted. Figure 4 As shown, the method specifically includes the following steps:

[0075] S1: Mathematical model of a typical honeycomb unit that constructs a regular hexagonal framework.

[0076] Since the honeycomb porous structure has strong regularity and periodicity as a whole, the overall structural model is composed of a periodic array of uniform units. Therefore, the basic parameters of ordinary honeycomb units are defined first. The cross-sectional shape of ordinary honeycomb units is usually a regular hexagon. The side length and wall thickness of ordinary honeycomb units are defined, and on this basis, innovative optimization design of ordinary honeycomb units is carried out.

[0077] like Figure 5 As shown, the wall thickness of a common honeycomb unit is defined as t0 and the side length is L. The cross section of a common honeycomb unit is a regular hexagon, and the size and shape of its cell type are mainly determined by the wall thickness t0 and the side length L.

[0078] Next, if Figure 6 and Figure 7 As shown, by continuing to perform array operations and stretching on ordinary honeycomb units, the plane view and three-dimensional simplified model corresponding to the honeycomb porous structure can be obtained.

[0079] S2: Use the SIMP variable density topology optimization strategy to perform topology optimization analysis on ordinary honeycomb units.

[0080] In the field of material optimization design, the variable density method is one of the most commonly used optimization analysis techniques. The key concept of the variable density method is to artificially introduce a hypothetical material density variable, assuming a functional relationship between the material's physical parameters and the hypothetical material density. Based on these assumptions, a topology optimization model is established. During topology optimization, the density of each material unit is used as a topological design variable, transforming the structural topology optimization problem into an optimal material distribution problem.

[0081] At present, the density interpolation model that is more widely used in variable density topology optimization methods is: Solid Isotropic Material Penalty Model (SIMP). The SIMP model is a density-stiffness interpolation model commonly used in topology optimization problems. This model assumes that the material density is a constant within the unit and uses it as a design variable, and penalizes the intermediate density values by introducing a penalty factor. The material properties are simulated by an exponential function of the unit density, which has the characteristics of simple calculation and high iterative efficiency and is widely used. The topology optimization solver used in the actual application of this embodiment is the OptiStruct platform in the commercial software AltairSolidthinking Inspire2021. The OptiStruct topology optimization modeling method is based on the variable density method of the SIMP interpolation model to perform topological optimization design of porous structural units.

[0082] The optimization process in this embodiment also generally includes the following process:

[0083] (1) First, considering that OptiStruct topology optimization is based on finite elements, it is necessary to establish a finite element physical model of the honeycomb unit structure and discretize the continuum into tiny units. Figure 8 This is the finite element physical model of the common honeycomb structure created in this embodiment. The space inside the hexagonal frame in the figure is the design space of this structural design.

[0084] In this embodiment, since the wall thickness t is a key factor affecting the porosity of the porous structure, and porosity is the dominant factor affecting the performance of the porous structure, the innovative internal reinforcement design of the ordinary honeycomb porous structure will inevitably lead to a decrease in porosity relative to the ordinary honeycomb porous structure, thereby affecting the performance of the porous structure. Therefore, in order to ensure that the constructed new honeycomb porous structure has the same quality and porosity as the ordinary honeycomb porous structure, a common honeycomb unit body with a wall thickness of u = t / 2 and other parameters remaining unchanged is selected for topological optimization design. The design area is defined as the inner pore filling part of the ordinary honeycomb unit body, and the material is defined as 316L stainless steel. The relevant parameters are shown in Table 1:

[0085] Table 1: Basic parameters of 316L stainless steel material used in the optimization problem

[0086] Yield strength (Mpa) Elastic modulus (Mpa) <![CDATA[Density (g / cm 3 )]]> Poisson's ratio 451 171 7.954 0.3

[0087] (2) Secondly, after the finite element model is established, the load conditions and boundary conditions for the corresponding working conditions need to be set. Regarding the application of loads, since honeycomb porous structures are usually used as internal filling structures, their load conditions have different types. Based on the design objectives, the objectives involved in this embodiment are summarized into three types: compression-first, shear-first, and torsion-first.

[0088] in, Figure 9-11 Schematic diagrams of the distribution of load conditions and boundary conditions corresponding to the design process of three different honeycomb porous structures, namely compression-first type, shear-first type and torsion-first type, in this embodiment.

[0089] (3) Next, define the topology optimization problem, that is, determine the three elements of the optimization design: design variables, objective function, and constraints. The topology optimization analysis process of this embodiment uses unit density as the design variable, maximizing unit stiffness as the optimization goal, and porosity as the constraint. The topology optimization model used is as follows:

[0090]

[0091] In the above formula, x is the design variable; x i is the cell density; x min and x maxare the minimum and maximum unit density in the design area respectively; C(x) is the flexibility matrix of the design area; F is the load matrix of the entire structure; U is the displacement matrix of the entire structure; K is the stiffness matrix of the entire structure; k0 represents the stiffness matrix of the specified design area; V is the volume of the optimized structure; V0 is the volume of the specified design area, v i is the volume of the unit; μ is the volume ratio of the structure after topology optimization within the specified design area to the original structure within the design area; n is the total number of units in the mesh; and p is the preset model penalty coefficient.

[0092] (4) Finally, after performing topology optimization design on a common honeycomb unit body, this embodiment outputs its model and data for three-dimensional reconstruction.

[0093] S3: Based on the result data after topology optimization analysis, curve fitting is performed on the model of the structure to obtain the outline of the basic contour of the new honeycomb unit body.

[0094] The basic outlines of the three different honeycomb porous structures of the optimized compression priority type, shear priority type and torsion priority type in this embodiment are roughly as follows: Figure 12-14 As shown in the figure, the basic forms of the optimal honeycomb porous structure under three different optimization objectives can be seen. However, since the optimization results are actually irregular, it is not conducive to the subsequent theoretical analysis and design finalization test. Therefore, the optimization results need to be standardized before the design is finalized.

[0095] S4: Simplify the outline of the basic contour of the optimized new honeycomb unit body and measure the key parameters used to characterize the structural characteristics of the honeycomb unit.

[0096] This embodiment completes the task of graphics simplification in Magics software, according to Figure 12-14 The contour map is used to perform morphological standardization on the basic unit of the optimized honeycomb porous structure. Figure 12 and Figure 13 The interior of the polygonal outer frame is basically a mesh structure. During the standardization stage, each reinforcement rib is simplified into a rod-type structure, and the structural thickness of different rod structures is reasonably set according to the outline profile drawing. At the same time, the local structure of different rod connections is fine-tuned. Figure 14 There is no structure inside the polygonal outer frame, which is manifested by the different thickness distributions at different locations inside the outer frame. In this case, it is still designed as a ring structure. The mathematical models and key structural parameters of the compression-first, shear-first, and torsion-first types are as follows: Figure 1-3 shown.

[0097] S5: Reconstruct a simplified model of the new honeycomb unit based on the key structural parameters measured in the previous step, and generate a three-dimensional model of the corresponding honeycomb porous structure.

[0098] Specifically, this embodiment uses CAD and SolidWorks software as modeling tools to complete the construction of the three-dimensional model of the information honeycomb porous structure. Among them, the plane view and three-dimensional simplified model of the compression-first honeycomb porous structure are established as shown in FIG. Figure 15 and Figure 16 As shown; the plane view and three-dimensional simplified model of the shear priority honeycomb porous structure are shown in Figure 17 and Figure 18 The plane view and three-dimensional simplified model of the torsion-preferred honeycomb porous structure are shown in Figure 19 and Figure 20 shown.

[0099] S6: Use the finite element analysis method (FEA) to optimize the design and verify the new honeycomb unit body, simulate the stress, strain and deformation of different structures under the same load conditions, and obtain the comprehensive mechanical properties and energy absorption performance data of the optimized new honeycomb unit body.

[0100] S7: cyclically execute steps S2-S6 until the spatial configuration of the honeycomb porous structure that meets the performance requirements is determined, and the honeycomb porous material required for the corresponding spatial configuration is designed; finally, sample trial production and performance verification are carried out.

[0101] It's important to emphasize that each of the three load-oriented honeycomb porous structures designed in this embodiment possesses compressive, shear, and torsional resistance, though the three structures exhibit varying performance advantages and disadvantages in different dimensions. For example, the compression-first honeycomb porous structure not only exhibits outstanding compressive resistance but also outperforms the classic hexagonal honeycomb porous structure in shear and torsional resistance.

[0102] Example 2

[0103] Based on the solution in Example 1, this embodiment further provides a load-oriented honeycomb porous material, which is composed of multiple honeycomb units arranged in a plane or three-dimensional space. The honeycomb units adopt one or more of the three types of load-oriented honeycomb porous structures with different performance as described in Example 1. This load-oriented honeycomb porous material is processed using 3D printing technology.

[0104] Performance Testing

[0105] In order to verify the actual performance of the load-oriented honeycomb porous structure designed in this embodiment, the following performance test experiment was specially formulated:

[0106] Based on the ISO 13314-2011 standard, the quasi-static compression test was carried out on the AG-100-Xplus high-performance universal testing machine with a loading rate of 2 mm / min and a maximum loading pressure of 100 KN. Uniaxial quasi-static compression tests were carried out on the honeycomb porous structure and its optimized structure specimens. To ensure the accuracy of the test results, the loading direction of all specimens is perpendicular to the SLM building direction. During the test, the upper and lower ends of the specimen are ensured to be flat, and can fit well with the upper and lower pressure head surfaces in the fixture, and are placed in the center of the pressure head to ensure that the specimen can be completely covered by the pressure head, thereby maintaining uniform force on the specimen during the test. After the test, the load-displacement data is output. The stress value is determined by dividing the applied load by the initial cross-sectional area of the specimen perpendicular to the loading direction, and the strain value is determined by dividing the total compression displacement of the specimen by the initial height of the specimen. The stress-strain curve obtained by sorting the test data is as follows Figure 21 shown

[0107] It can be seen from the experimental data that the optimized honeycomb porous structure has greatly improved both the elastic modulus and the yield strength compared with the traditional honeycomb porous structure, and the comprehensive mechanical properties have been improved. This also verifies the feasibility of the load-oriented honeycomb porous structure optimization design method and realizes the macro-mechanical properties regulation of honeycomb porous materials.

[0108] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A load-oriented honeycomb porous structure comprising three spatial configurations: compression-first, shear-first, and torsion-first; characterized in that: According to cross-sectional analysis, the basic unit of the compression-first honeycomb porous structure includes a regular hexagonal outer frame and an internal reinforcing rib structure, with the side length of the outer frame being L and the wall thickness being t1; the sides of the outer frame are divided into numbers 1-6 in a clockwise direction; then, the reinforcing rib structure includes a first reinforcing portion and a second reinforcing portion symmetrically distributed on both sides of the inner portion of the outer frame; the first reinforcing portion includes a first V-rod composed of two long rods of equal length, and a second V-rod composed of two short rods of equal length; the two ends of the first V-rod are respectively connected to the midpoints of the inner sides of sides 2 and 6; the angle of the first V-rod is θ1=140° and the vertex of the angle is close to side 1; the second V-rod crosses the first V-rod in an X-shape, the ends of the two short rods are connected to the inner side of side 1, and the angle between adjacent long rods and short rods is θ2=70°; the inner side of the angle between the two short rods and the two long rods also includes an arc segment with a radius R=0.11L facing outward; the second reinforcing portion is connected to the inner walls of sides 3, 4, and 5.

2. The load-oriented honeycomb porous structure according to claim 1, characterized in that: In the compression-prioritized honeycomb porous structure, the wall thickness of the reinforcing rib structure is uniform; and the wall thickness of the outer frame is twice the wall thickness of the reinforcing rib structure.

3. The load-oriented honeycomb porous structure according to claim 1, wherein: According to cross-sectional analysis, the basic unit of the shear-preferential honeycomb porous structure includes a regular hexagonal outer frame and an internal reinforcing rib structure. The side length of the outer frame is defined as L, and the sides of the outer frame are numbered 1-6 in a clockwise direction. Then, the internal reinforcing rib structure of the shear-preferential honeycomb porous structure includes: Two equal-length, cross-shaped rods, with their four endpoints connected to the inner walls of sides 2, 3, 5, and 6, respectively; Two equal-length support rods, one end of each of which is vertically connected to the inner sides of sides 1 and 4 respectively; Two third V-rods formed by two short rods of equal length, each with an angle of θ=140°; the vertices of the angles in the third V-rods are connected to the other ends of the two support rods; and the ends of the third V-rods are connected to the two adjacent long rods. At the intersection of the long rod and the short rod, the interior of the acute angle side also includes an arc segment with a radius R=0.04L.

4. The load-oriented honeycomb porous structure according to claim 3, wherein: In the shear-preferred honeycomb porous structure, the support rod portion and the section extending from the intersection of the short rod and the long rod to the outer frame are all thickened sections, and the wall thickness of the remaining section except the thickened section is uniform and relatively thin.

5. The load-oriented honeycomb porous structure according to claim 1, wherein: According to cross-sectional analysis, the outer contour of the basic unit of the torsion-preferred honeycomb porous structure is a regular hexagon, and the internal hollow structure is a symmetrical olive shape; the edges in the outer contour are defined as 1-6 in clockwise order; then, The two continuous sections extending from the midpoint of side 2 to the midpoint of side 3, and from the midpoint of side 5 to the midpoint of side 6 are both sections with uniform wall thickness; the remaining sections are sections with non-uniform wall thickness; and the inner walls of the sections from the midpoint of side 3 to the midpoint of side 5, and from the midpoint of side 6 to the midpoint of side 2 are both continuous inward-concave arc sections with a radius R=0.86L.

6. A load-oriented honeycomb porous material, characterized in that: It is formed by a plurality of honeycomb units arranged in an array in a plane or three-dimensional space, and the honeycomb units adopt one or more types of the load-oriented honeycomb porous structures as described in any one of claims 1 to 5.

7. The load-oriented honeycomb porous material according to claim 6, characterized in that: It is made using 3D printing technology.

8. A method for designing a load-oriented honeycomb porous material, characterized by: It is used to design a load-oriented honeycomb porous material as described in any one of claims 6 to 7; the design method comprises the following steps: S1: Mathematical model of a typical honeycomb unit for constructing a regular hexagonal framework; S2: Use the SIMP variable density topology optimization strategy to perform topology optimization analysis on ordinary honeycomb units; The topology optimization model used is as follows: In the above formula, x is the design variable; x i is the cell density, x min and x max are the minimum and maximum unit density in the design area respectively; C(x) is the flexibility matrix of the design area; F is the load matrix of the entire structure; U is the displacement matrix of the entire structure; K is the stiffness matrix of the entire structure; k0 represents the stiffness matrix of the specified design area; V is the volume of the optimized structure; V0 is the volume of the specified design area, v i is the volume of the unit; μ is the volume ratio of the structure after topology optimization to the original structure in the specified design area; n is the total number of units in the mesh; p is the preset model penalty coefficient; S3: Based on the result data after topology optimization analysis, curve fitting is performed on the model of the structure to obtain the basic outline of the new honeycomb unit body; S4: Simplify the basic outline of the optimized new honeycomb unit and measure the key parameters used to characterize the structural characteristics of the honeycomb unit; S5: reconstructing a simplified model of the new honeycomb unit according to the key structural parameters measured in the previous step, and generating a corresponding three-dimensional model of the honeycomb porous structure; S6: Utilizing the finite element analysis method to verify the optimized design of the novel honeycomb unit body, simulating the stress, strain, and deformation of different structures under the same load conditions, and obtaining comprehensive mechanical properties and energy absorption performance data of the optimized novel honeycomb unit body; S7: cyclically execute steps S2-S6 until the spatial configuration of the honeycomb porous structure that meets the performance requirements is determined, and the honeycomb porous material required for the corresponding spatial configuration is designed; finally, sample trial production and performance verification are carried out.

9. The method for designing a load-oriented honeycomb porous material according to claim 8, wherein: In step S1, the mathematical model of the typical honeycomb unit is as follows: the wall thickness of the typical honeycomb unit body is defined as t0, the side length is L, the cross section of the typical honeycomb unit body is a regular hexagon, and the cell size and shape are mainly determined by the wall thickness t0 and the side length L.

10. The method for designing a load-oriented honeycomb porous material according to claim 8, wherein: In step S2, the topology optimization analysis process uses unit density as a design variable, unit stiffness maximization as an optimization goal, and porosity as a constraint condition.

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