Zero-Poisson-ratio honeycomb structure with enhanced deformability

Abstract

The invention discloses a zero-Poisson-ratio honeycomb structure with enhanced deformability, and relates to the technical field of mechanical metamaterial and light structure design. Compared with the prior art, larger axial displacement can be generated, the zero Poisson's ratio characteristic and the basic bearing capacity are not sacrificed, and the longer buffering stroke, the higher energy absorption capacity and the better deformation adaptability can be provided. The honeycomb structure comprises a plurality of honeycomb cell elements which are arranged on a two-dimensional plane in a transverse and longitudinal array mode. Each honeycomb cell element comprises two longitudinal inner folding wall plates and two transverse inner folding wall plates; the transverse inner folding wall plate comprises two transverse sub wall plate assemblies; the transverse sub-wall plate assembly comprises a first transverse sub-wall plate, a second transverse sub-wall plate and a third transverse sub-wall plate which extend inwards in an inclined mode. The outer end of the first transverse sub-wall plate is connected with the longitudinal sub-wall plate; the inner end of one second transverse sub-wall plate is connected with the inner end of the other second transverse sub-wall plate; the two ends of the third transverse sub-wall plate are connected with the inner end of the first transverse sub-wall plate and the outer end of the second transverse sub-wall plate through the inner folding connecting sub-wall plate respectively.

Description

Technical Field

[0001] This application relates to the field of mechanical metamaterials and lightweight structure design technology, and in particular to a zero Poisson's ratio honeycomb structure with enhanced deformation capacity. Background Technology

[0002] Honeycomb structures are widely used in various engineering fields due to their high specific strength, high specific stiffness, and excellent energy absorption characteristics. Among them, zero Poisson's ratio honeycomb structures, as a special type of mechanical metamaterial, can effectively suppress lateral deformation when subjected to axial loads, which is of great significance for structural components that need to maintain stable cross-sectional dimensions, such as aerospace cabins and medical implant stents.

[0003] The quadrangular star-shaped honeycomb structure is a typical zero Poisson's ratio topological configuration. Through its unique design of concave star-shaped cells, it can achieve a near-zero Poisson's ratio mechanical response during elastic deformation. However, in practical applications, it has been found that this structure has a relatively limited deformation capacity. Specifically, under the same load conditions, the quadrangular star-shaped honeycomb structure often rapidly enters densification or becomes unstable after reaching the end of its ideal zero Poisson's ratio deformation range, resulting in a short usable, effective deformation path. This characteristic limits its application potential in buffering and seismic isolation scenarios that require the absorption of large amounts of energy or the adaptation to large displacements.

[0004] Current improvements to zero Poisson's ratio structures primarily focus on further reducing the absolute value of the Poisson's ratio and increasing stiffness or strength, with few systematic optimizations addressing the crucial performance indicator of deformation capacity under load. Therefore, there is an urgent need to develop a honeycomb structure that can achieve greater deformation under the same load level while still robustly maintaining its zero Poisson's ratio characteristics. Summary of the Invention

[0005] The embodiments of this application provide a zero Poisson's ratio honeycomb structure with enhanced deformability. When subjected to the same axial load as the control structure, it can generate a larger axial displacement, thereby providing a longer buffer stroke, higher energy absorption capacity and better deformation adaptability without sacrificing the zero Poisson's ratio and basic load-bearing capacity.

[0006] To achieve the above objectives, embodiments of this application provide a zero Poisson's ratio honeycomb structure with enhanced deformability, comprising a plurality of honeycomb cells arranged in a horizontal and vertical array on a two-dimensional plane; each honeycomb cell includes two alternatingly connected vertically folded wall panels and two horizontally folded wall panels; each vertically folded wall panel includes two vertically symmetrically arranged longitudinally inclined sub-wall panels; each horizontally folded wall panel includes two horizontally oriented sub-wall panel assemblies arranged horizontally and vertically; each horizontally oriented sub-wall panel assembly includes a first horizontally oriented sub-wall panel, a second horizontally oriented sub-wall panel, and a third horizontally oriented sub-wall panel, all extending inwardly; the outer end of the first horizontally oriented sub-wall panel is connected to the end of the vertically oriented sub-wall panel; the inner end of the second horizontally oriented sub-wall panel is connected to the inner end of the second horizontally oriented sub-wall panel in another horizontally oriented sub-wall panel assembly; the two ends of the third horizontally oriented sub-wall panel are respectively connected to the inner end of the first horizontally oriented sub-wall panel and the outer end of the second horizontally oriented sub-wall panel through an inwardly folded connecting sub-wall panel.

[0007] Furthermore, the array step size of the cell in the horizontal direction is the width of the cell; and the array step size in the vertical direction is the length of the cell.

[0008] Furthermore, the two longitudinal sub-panels form a "V" shaped structure.

[0009] Furthermore, the second transverse sub-panel in two adjacent sets of the transverse sub-panel assemblies forms a “V” shape.

[0010] Furthermore, the angle θ between the longitudinal sub-wall panel and the vertical direction ranges from 10° to 80°.

[0011] Furthermore, the second transverse sub-wall panel is located in the same plane as the first transverse sub-wall panel; the third transverse sub-wall panel is parallel to the first transverse sub-wall panel.

[0012] Furthermore, the angle α between the first transverse sub-panel and the horizontal direction ranges from 30° to 60°.

[0013] Furthermore, the inner folding connecting sub-wall panel forms an inner folding angle γ with the first transverse sub-wall panel, the third transverse sub-wall panel, and the second transverse sub-wall panel; the range of the inner folding angle γ is 30°~60°.

[0014] Furthermore, multiple of the aforementioned cellular cells are integrally formed using 3D printing technology.

[0015] This application has the following advantages over the prior art: 1. The zero Poisson's ratio honeycomb structure with enhanced deformation capability in the embodiments of this application achieves greater recoverable or usable deformation under the same load level while maintaining excellent zero Poisson's ratio characteristics by setting honeycomb cells including two alternating longitudinal inner folded wall plates and two transverse inner folded wall plates, thereby directly enhancing the energy absorption efficiency and buffering performance of the structure.

[0016] 2. The improved deformation capacity of the zero Poisson's ratio honeycomb structure in the embodiments of this application is not achieved at the cost of significantly sacrificing stiffness, strength, or the zero Poisson's ratio effect, but rather through geometric optimization to achieve a synergistic improvement of multiple properties.

[0017] 3. The enhancement effect of the zero Poisson's ratio honeycomb structure with enhanced deformation capability in the embodiments of this application can be controlled by adjusting the geometric parameters of the honeycomb cells to meet the specific requirements of different application scenarios for load level, deformation amount and Poisson's ratio.

[0018] 4. The zero Poisson's ratio honeycomb structure with enhanced deformability in the embodiments of this application still retains the characteristics of two-dimensional plates or three-dimensional lattices, and is compatible with existing mature processes such as laser cutting, stamping, folding, and additive manufacturing, making it easy to realize engineering applications. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the zero Poisson's ratio honeycomb structure with enhanced deformability according to an embodiment of this application; Figure 2 This is a schematic diagram of a single cell in a zero Poisson's ratio honeycomb structure with enhanced deformability according to an embodiment of this application. Figure 3 This is a comparison diagram showing the deformation of a single cell in the zero Poisson's ratio honeycomb structure with enhanced deformation capability according to the embodiments of this application and a single cell in a traditional quadrangular star-shaped zero Poisson's ratio honeycomb structure under the same load. Figure 4 A comparison of the deformation of a single cell in a zero Poisson's ratio honeycomb structure with enhanced deformation capacity and a single cell in a traditional quadrangular star-shaped zero Poisson's ratio honeycomb structure under the same load. Detailed Implementation

[0021] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0023] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation", "connection" and "joining" should be interpreted broadly, for example, they can refer to fixed connections, detachable connections, or integral connections; those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0024] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" can explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0025] This application provides a zero Poisson's ratio honeycomb structure with enhanced deformability. It not only possesses the characteristic of zero Poisson's ratio but also allows for separate design of in-plane and out-of-plane mechanical properties. Furthermore, due to the presence of the inward-folding structure in the transverse honeycomb wall panels, it exhibits greater deformability under the same load compared to traditional four-cornered star-shaped honeycombs; that is, less force is required to achieve the same zero Poisson's ratio deformation. This application is particularly suitable for applications requiring lateral dimensional stability under large deformations, such as flexible robots, deployable aerospace structures, biomedical scaffolds, and high-performance protective equipment.

[0026] Reference Figure 1 and Figure 2 The zero Poisson's ratio honeycomb structure with enhanced deformability in this application embodiment includes a plurality of honeycomb cells 10 arranged periodically in a plane. Periodic arrangement in a plane specifically refers to their array arrangement (rectangular array) along the horizontal and vertical directions on a two-dimensional plane. The array step size of the honeycomb cells in the horizontal direction is the width of the honeycomb cell, and the array step size in the vertical direction is the length of the honeycomb cell. The honeycomb structure is formed using 3D printing technology, and a variety of 3D printing materials can be selected to further improve the performance of the honeycomb structure at the material level.

[0027] Reference Figure 2 The cell 10 includes two alternating longitudinal inward folded wall plates 1 and two transverse inward folded wall plates 2.

[0028] The longitudinal inward-folding wall panel 1 includes two longitudinal sub-wall panels 11 that are symmetrically arranged vertically and extend inwardly. The angle θ between the longitudinal sub-wall panel 11 and the vertical direction ranges from 10° to 80°, preferably from 10° to 30°. The two longitudinal sub-wall panels form a "V" shape structure.

[0029] In this embodiment, the length L1 of the longitudinal sub-wall panel 11 is 31.058 mm, and θ is 15°.

[0030] The transverse inward folding wall panel 2 includes two transverse sub-wall panel assemblies 21 arranged with left and right supports.

[0031] The transverse sub-panel assembly 21 includes a first transverse sub-panel 211, a second transverse sub-panel 212, and a third transverse sub-panel 213, all extending inwardly at an inward angle. The outer end of the first transverse sub-panel 211 is connected to the end of the longitudinal sub-panel 11, and the inner end of the second transverse sub-panel 212 is connected to the inner end of the second transverse sub-panel 212 in another transverse sub-panel assembly 21 to form a "V" shaped structure.

[0032] The two ends of the third transverse sub-wall panel 213 are respectively connected to the inner end of the first transverse sub-wall panel 211 and the outer end of the second transverse sub-wall panel 212 through an inward folding connecting sub-wall panel 214.

[0033] The angle α between the first transverse sub-wall panel 211 and the horizontal direction ranges from 30° to 60°, preferably from 40° to 50°. The second transverse sub-wall panel 212 and the first transverse sub-wall panel 211 are located on the same plane. The third transverse sub-wall panel 213 is parallel to the first transverse sub-wall panel 211.

[0034] The inner fold connecting sub-wall panel 214 forms an inner fold angle γ with the first horizontal sub-wall panel 211, the second horizontal sub-wall panel 212 and the third horizontal sub-wall panel 213. The range of the inner fold angle γ is 30°~60°, preferably 30°~50°.

[0035] In this embodiment, the length of the first transverse sub-panel 211 is L2 = 15.562 mm, the length of the second transverse sub-panel 212 is L3 = 16.574 mm, the length of the third transverse sub-panel 213 is L4 = 16.683 mm, and the length of the inwardly folded connecting sub-panel 214 is L5 = 6.168 mm. The angle α between the first transverse sub-panel 211 and the horizontal direction is 50°, and the inward folding angle γ is 30°. It should be noted that the thickness t of each panel satisfies the requirement that the honeycomb panel does not interfere with other panels except for adjacent panels.

[0036] In summary, the zero Poisson's ratio honeycomb structure with enhanced deformability in the embodiments of this application is a single cell (the topological configuration of the honeycomb cell is obtained by optimizing the deformation mechanism of classic polygonal (such as quadrilateral, hexagonal) or star-shaped structures). Its core lies in the fact that by synergistically redesigning the length ratio, connection angle and spatial arrangement of the cell wall panels, the internal force transmission path and deformation mode of the structure under axial pressure or tension are changed.

[0037] Specifically, the optimized configuration enables the load to be more effectively converted into controlled bending or cooperative rotation of specific wall panels, rather than prematurely inducing local stress concentration or overall instability. For example, by adjusting the proportional relationship of key wall lengths (L1, L2, L3, L4, L5) and the inclination angles θ, α, γ, the structure is made to have a smoother initial stage of yielding or buckling, thus allowing the structure to undergo a longer, more stable deformation phase in the process of reaching the same peak load.

[0038] To facilitate structural design and analysis, the dimensional parameters of the three cells in this application are dimensionless. By periodically arranging the individual cells of this representative honeycomb structure in the xy plane to form a zero Poisson's ratio honeycomb structure, as shown... Figure 2 As shown, the array distance along the horizontal direction in the two-dimensional plane is the width of the cell of the honeycomb structure, i.e., 2(L2+L3+L4-2×L5×COSγ)×COSα, and the array distance along the vertical direction is the length of the cell of the honeycomb structure, i.e., 2L1×COSθ. The obtained structure is stretched by h along the normal of the two-dimensional structure.

[0039] This application presents a simulation analysis of a zero Poisson's ratio honeycomb structure with enhanced deformation capability. The model input parameters are L1=31.058mm, L2=15.562mm, L3=16.574mm, L4=16.683mm, L5=6.168mm, α=50°, θ=15°, γ=30°, and h=100mm. Using the finite element software ANSYS, load-bearing wall panels are established on both sides of the honeycomb in the horizontal direction, with an input load of 10N. The calculation results show that the in-plane Poisson's ratio of the honeycomb structure in this application is 0.0005, exhibiting zero Poisson's ratio characteristics. Based on the finite element calculation results, the comparison between the zero Poisson's ratio deformation along the load direction of the honeycomb structure in this application embodiment and the traditional four-cornered star-shaped zero Poisson's ratio honeycomb structure is as follows: Figure 3 As shown.

[0040] Reference Figure 4 Experimental and simulation analyses show that, under quasi-static tensile conditions, the axial strain of the structure described in this invention can be increased by an average of about 25% compared with that of a traditional quadrangular star honeycomb structure with the same relative density, material and boundary conditions, under the same characteristic load.

[0041] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A zero Poisson's ratio honeycomb structure with enhanced deformability, characterized in that, It includes multiple honeycomb cells arranged in a horizontal and vertical array on a two-dimensional plane; each honeycomb cell includes two alternating vertically folded wall panels and two horizontally folded wall panels; each vertically folded wall panel includes two vertically symmetrically arranged longitudinally inclined sub-wall panels; each horizontally folded wall panel includes two horizontally oriented sub-wall panel assemblies arranged to support each other from left to right; each horizontally oriented sub-wall panel assembly includes a first horizontally oriented sub-wall panel, a second horizontally oriented sub-wall panel, and a third horizontally oriented sub-wall panel, all of which extend inwardly; the outer end of the first horizontally oriented sub-wall panel is connected to the end of the vertically oriented sub-wall panel; the inner end of the second horizontally oriented sub-wall panel is connected to the inner end of the second horizontally oriented sub-wall panel in another horizontally oriented sub-wall panel assembly; the two ends of the third horizontally oriented sub-wall panel are respectively connected to the inner end of the first horizontally oriented sub-wall panel and the outer end of the second horizontally oriented sub-wall panel through an inwardly folded connecting sub-wall panel.

2. The zero Poisson's ratio honeycomb structure with enhanced deformability according to claim 1, characterized in that, The array step size of the cell in the horizontal direction is the width of the cell; the array step size in the vertical direction is the length of the cell.

3. The zero Poisson's ratio honeycomb structure with enhanced deformability according to claim 2, characterized in that, The two longitudinal sub-panels form a "V" shaped structure.

4. The zero Poisson's ratio honeycomb structure with enhanced deformability according to claim 3, characterized in that, The second transverse sub-panel in two adjacent sets of the transverse sub-panel assemblies forms a "V" shape.

5. The zero Poisson's ratio honeycomb structure with enhanced deformability according to claim 4, characterized in that, The angle θ between the longitudinal sub-wall panel and the vertical direction ranges from 10° to 80°.

6. The zero Poisson's ratio honeycomb structure with enhanced deformability according to claim 5, characterized in that, The second transverse sub-wall panel is located in the same plane as the first transverse sub-wall panel; the third transverse sub-wall panel is parallel to the first transverse sub-wall panel.

7. The zero Poisson's ratio honeycomb structure with enhanced deformability according to claim 6, characterized in that, The angle α between the first transverse sub-wall panel and the horizontal direction ranges from 30° to 60°.

8. The zero Poisson's ratio honeycomb structure with enhanced deformability according to claim 7, characterized in that, The inner folding connecting sub-wall panel forms an inner folding angle γ with the first horizontal sub-wall panel, the third horizontal sub-wall panel, and the second horizontal sub-wall panel; the range of the inner folding angle γ is 30°~60°.

9. The zero Poisson's ratio honeycomb structure with enhanced deformability according to claim 8, characterized in that, Multiple of the aforementioned cell units are integrally formed using 3D printing technology.

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