Tertiary bipolar ligament negative Poisson's ratio honeycomb lattice structure, application and regulation and control method

Abstract

The invention relates to the technical field of structures, in particular to a cubic double-pole ligament negative Poisson's ratio honeycomb lattice structure which comprises a plurality of honeycomb unit cells which are assembled in a linkage mode. Each honeycomb unit cell comprises two straight edges which are symmetrically arranged, the two ends of each straight edge are respectively connected with a cubic double-pole ligament, the four cubic double-pole ligaments are respectively symmetrical, the opposite ends of the two cubic double-pole ligaments on the same side are connected to linkage edges, and the two linkage edges are symmetrical to each other and are located on the same plane; the two straight edges, the four cubic double-pole ligaments and the two linkage edges form a linkage structure which is connected with each other. The invention aims to provide a cubic double-pole ligament negative Poisson's ratio honeycomb lattice structure, an oblique straight ligament of a traditional concave hexagonal unit cell is modified into a cubic double-pole curve ligament, and the optimization potential of energy absorption and impact resistance is enhanced.

Description

Technical Field

[0001] The present invention relates to the field of structural technology, and particularly to a cubic double-pole ligament negative Poisson's ratio honeycomb lattice structure, its application, and regulation method. Background Art

[0002] Negative Poisson's ratio metamaterials, also known as auxetic materials, as a branch of mechanical metamaterials, are unique due to their negative Poisson's ratio property - when subjected to axial tension, these materials exhibit transverse expansion behavior. This counterintuitive mechanical response stems from the special geometric configuration of their unit cells. According to the structural topology characteristics, auxetic design can be divided into five categories: re-entrant honeycomb structures, chiral structures, rotating rigid polygon structures, wrinkled sheet structures, and porous sheet structures. The advantages of auxetic materials are reflected in multiple dimensions: their negative Poisson's ratio property can significantly improve the fracture resistance, indentation resistance, and energy absorption capacity of materials, thus having great application potential in the field of load buffering. For example, in protective engineering, auxetic structures have been successfully used in helmet design and impact energy absorption devices; in the aerospace field, they are integrated into sandwich panels to reduce the risk of vibration and fatigue failure; in addition, the synchronous bending curvature characteristics generated when they are bent enable auxetic materials to conform to the contours of organisms, showing excellent conformability in biomedical devices such as vascular stents and wearable sensors.

[0003] However, traditional auxetic materials (especially those using straight ligament configurations, such as re-entrant honeycomb structures) have inherent defects in their deformation mechanisms. Under compressive loads, the rigid hinges and straight ligaments of these structures generate local stress concentrations at the nodes, resulting in non-uniform deformation. This instability stems from the geometric constraints of the straight ligaments - which hinder the redistribution of stress, exacerbate the premature buckling and collapse of the structure, thereby reducing the reliability of such structures in dynamic application scenarios such as impact protection or vibration damping. In addition, the energy absorption capacity of traditional auxetic materials is limited by their instability characteristics under compressive loads. Although their negative Poisson's ratio behavior can theoretically enhance energy absorption through synchronous bending deformation, the straight ligament design is prone to buckling and often collapses before the structure is fully densified.

[0004] To break through these limitations, recent research has begun to explore replacing traditional straight configurations with curved ligaments. For example, sinusoidal, wavy, elliptical, and circular ligament configurations have been proposed, which reduce nodal stress concentration through a more uniform stress field distribution. Simulation models in these literatures show that curvature design can delay buckling and enhance energy absorption by controlling the bending of ligaments. However, existing designs are mostly based on fixed-curvature geometries (such as circular arcs or sine curves), making it difficult to finely regulate the structural response according to specific application requirements. In addition, bionic, self-similar, and hierarchical designs are used to promote sequential buckling and stabilize the deformation path, thereby improving the energy absorption capacity. However, such designs usually require complex geometries, not only relying on high-performance computing resources for optimization but also significantly increasing the manufacturing cost.

[0005] Therefore, there is an urgent need to propose a new design method for negative Poisson's ratio honeycomb lattice structures to overcome the poor compressive stability and low energy absorption characteristics of existing structures. Summary of the Invention

[0006] Aiming at the above defects, the purpose of the present invention is to propose a cubic double-pole ligament negative Poisson's ratio honeycomb lattice structure, which modifies the oblique straight ligaments of traditional concave hexagonal unit cells into cubic double-pole curve ligaments, enhancing the optimization potential of energy absorption and anti-impact performance.

[0007] To achieve this purpose, the present invention adopts the following technical solutions:

[0008] The cubic double-pole ligament negative Poisson's ratio honeycomb lattice structure includes a plurality of honeycomb unit cells, and the plurality of honeycomb unit cells are assembled in a linked manner;

[0009] The honeycomb unit cell includes two symmetrically arranged straight edges, and each end of the two straight edges is connected to a cubic double-pole ligament. The four cubic double-pole ligaments are respectively symmetric, and the relative ends of the two cubic double-pole ligaments on the same side are connected to a linkage edge. The two linkage edges are symmetric and in the same plane;

[0010] The two straight edges, the four cubic double-pole ligaments, and the two linkage edges form a connected linkage structure.

[0011] Further, the cubic double-pole ligament is in an "N" shape, including a first bending section, a first pole, a second bending section, a second pole, and a third bending section;

[0012] One end of the first bending section is connected to one end of the straight edge, and the other end is connected to one end of the second bending section. The connection position of the first bending section and the second bending section is the first pole; the other end of the second bending section is connected to one end of the third bending section, and the connection position of the second bending section and the third bending section is the second pole; the other section of the third bending section is connected to the linkage edge.

[0013] Furthermore, the honeycomb unit cells are connected vertically by sharing straight edges and horizontally by interconnected linkage edges, so as to form a honeycomb lattice structure composed of multiple honeycomb unit cells.

[0014] On the other hand, a regulation method for a cubic double-pole ligament negative Poisson's ratio honeycomb lattice structure is proposed. This method is used for the cubic double-pole ligament negative Poisson's ratio honeycomb lattice structure and includes the following steps:

[0015] S1. Set parameter constraints, and the parameter constraints are limited as follows:

[0016] ;

[0017] ;

[0018] ;

[0019] ;

[0020] To meet the target geometric requirements, the main constraint condition stipulates that a 3 > 0 and Δ > 0 to ensure the existence of two independent extreme points;

[0021] Here, x 1 and x 2 respectively represent the abscissas of the two extreme points of the function;

[0022] The secondary constraint condition requires that 0 < x 1 , x 2 < (l 1 - h 1 ) / 2, thereby limiting the extreme value coordinates within the design domain. At the same time, it is accompanied by the restrictions f(x 1 ) < h 2 / 2 and f(x 2 ) ≥ 0 to ensure compatibility;

[0023] Through the conditional equation a 1 = h 2 / (l 1 - h 1 ) – [a 2 (l 1 - h 1 )] / 2 – [a 3 (l 1 - h 1 )²] / 4, the continuity constraint at the structural node is achieved;

[0024] The honeycomb unit cell size includes a straight edge length of l 1 , a linkage edge spacing of h 1 , and a straight edge spacing of h 2, the thickness of the straight edge is t; a 1 , a 2 , a 3 are the three coefficients of the cubic function, a 1 is obtained by calculating through the conditional formula, a 2 and a 3 are input according to the requirements of Young's modulus and Poisson's ratio. The cubic function is defined as in the form of y = a 1 x + a 2 x 2 + a 3 x 3 of the polynomial function. The coordinate origin is defined at the vertical center O point of the linkage edge. The positive x-axis direction is defined horizontally to the right along the linkage edge, and the positive y-axis direction is defined vertically upward perpendicular to the linkage edge; Since the cubic double-pole ligament passes through the coordinate origin O point, therefore a 0 = 0, where a 1 is the first-order term coefficient, a 2 is the second-order term coefficient, a 3 is the third-order term coefficient;

[0025] S2. Input the honeycomb unit cell size and determine whether the honeycomb unit cell size parameters meet the parameter constraints. If the honeycomb unit cell size does not meet the parameter constraints, it needs to be adjusted and re-input;

[0026] S3. Prediction of Young's modulus and Poisson's ratio. If the unit cell size parameters meet the parameter constraints, substitute the honeycomb unit cell size data that meets the parameter constraints into the Young's modulus and Poisson's ratio prediction formulas to predict the Young's modulus and Poisson's ratio of the honeycomb unit cell of this data;

[0027] S4. Regulation of Young's modulus and Poisson's ratio. Adjust the honeycomb unit cell size parameters used in the prediction through the Young's modulus and Poisson's ratio regulation methods;

[0028] Adjustment of Young's modulus. Increase h 2 ; or increase a 2 and decrease a 3 ; or decrease l 1 ; or increase t to increase Young's modulus; Decrease h 2 ; or decrease a 2 and increase a 3 ; or increase l 1 ; or decrease t to reduce Young's modulus;

[0029] Regulation of Poisson's ratio. Increase h 2 ; or increase a 2 and decrease a 3 ; or decrease l 1 ; or decrease h 1 to enhance the effect of negative Poisson's ratio; Decrease h 2; or decrease a 2 and increase a 3 ; or increase l 1 ; or increase h 1 to reduce the effect of negative Poisson's ratio.

[0030] Under quasi-static compression, it exhibits stable compressive deformation and gradually enhanced stress-strain behavior, significantly improving the energy absorption characteristics; it has excellent impact energy absorption and peak acceleration attenuation capabilities;

[0031] Furthermore; in step S3, in step S3, the prediction formulas for the effective Young's modulus and Poisson's ratio of honeycomb single cells under small deformations are derived using Castigliano's second theorem:

[0032] ;

[0033] ;

[0034] where, E y is the effective elastic modulus; v xy is the Poisson's ratio; E s is the elastic modulus of the base material.

[0035] In a third aspect, a fin using a cubic double-pole ligament negative Poisson's ratio honeycomb lattice structure is proposed, which is used as the framework of the blade structure of the fin.

[0036] One of the above technical solutions includes the following beneficial effects: Compared with the traditional design solution, the cubic ligament significantly enhances the optimization potential of energy absorption and impact resistance performance. In addition, compared with the traditional concave hexagonal single-cell structure, the adjustment space of this solution is larger. The cubic double-pole ligament negative Poisson's ratio honeycomb lattice structure of the present invention can change the mechanical properties, energy absorption characteristics and deformation degree through parameter adjustment. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a schematic diagram of the mechanism of a traditional concave hexagonal single cell;

[0038] Figure 2 is a schematic diagram of the mechanical model of the cubic double-pole ligament negative Poisson's ratio honeycomb single cell structure of the present invention;

[0039] Figure 3 is a schematic diagram of the model of the cubic double-pole ligament negative Poisson's ratio honeycomb structure of the present invention;

[0040] Figure 4 is a schematic diagram of the distribution of the effective elastic modulus of the honeycomb single cell of this solution with respect to the shape parameter of the cubic ligament;

[0041] Figure 5 is a schematic diagram of the distribution of the Poisson's ratio of the honeycomb single cell of this solution with respect to the shape parameter of the cubic ligament;

[0042] Figure 6 It is one of the schematic diagrams of the experimental results and simulation results of the 4×3 lattice structure under different compressive strains;

[0043] Figure 7 It is the second of the schematic diagrams of the experimental results and simulation results of the 4×3 lattice structure under different compressive strains;

[0044] Figure 8 It is the third of the schematic diagrams of the experimental results and simulation results of the 4×3 lattice structure under different compressive strains;

[0045] Figure 9 It is a schematic diagram of the stress-strain curve (a) and specific energy absorption-strain curve (b) of the 4×3 lattice structure with six groups of different ligament shape parameters;

[0046] Figure 10 It is for six different h 1 Schematic diagram of the stress-strain curve (a) and specific energy absorption-strain curve (b) of the 4×3 lattice structure with parameter;

[0047] Figure 11 It is a schematic diagram of the stress-strain curve (a) and specific energy absorption-strain curve (b) of the 4×3 lattice structure with three different h2 parameters;

[0048] Figure 12 It is a schematic diagram of the impact simulation of four honeycomb lattice structures;

[0049] Figure 13 For the acceleration-time curve (a) and impact response (b) of four lattice structures under an impact energy of 60 J;

[0050] Figure 14 For the acceleration-time curve (a) and impact response (b) of four lattice structures under an impact energy of 240 J;

[0051] Figure 15 For the acceleration-time curve (a) and impact response (b) of four lattice structures under an impact energy of 540 J.

[0052] Among them: straight edge 100, cubic double-pole ligament 200, linked edge 300. Detailed implementation manners

[0053] The following details the embodiments of the present invention. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation of the present invention.

[0054] AsFigure 2 and Figure 3 As shown in and

[0055] , the triple double - pole ligament negative Poisson's ratio honeycomb lattice structure includes a plurality of honeycomb unit cells, and the plurality of honeycomb unit cells are assembled in a linked manner with each other;

[0055] Each of the honeycomb unit cells includes two symmetrically arranged straight edges 100. At both ends of the two straight edges 100, a triple double - pole ligament 200 is respectively connected. The four triple double - pole ligaments 200 are respectively symmetric. The relative ends of the two triple double - pole ligaments 200 on the same side are connected to a linkage edge 300, and the two linkage edges 300 are symmetric with each other and in the same plane;

[0056] The two straight edges 100, the four triple double - pole ligaments 200 and the two linkage edges 300 form a linked structure that is interconnected.

[0057] Compared with the traditional design scheme, the triple double - pole ligament 200 significantly enhances the optimization potential of energy absorption and anti - impact performance. In addition, compared with the traditional concave hexagonal unit cell structure, this scheme has a larger adjustment space. The triple double - pole ligament negative Poisson's ratio honeycomb lattice structure of the present invention can change the mechanical properties, energy absorption characteristics and deformation degree through parameter adjustment.

[0058] Among them, the triple double - pole ligament is in an "N" shape, including a first bending section, a first pole, a second bending section, a second pole and a third bending section;

[0059] One end of the first bending section is connected to one end of the straight edge, and the other end is connected to one end of the second bending section. The connection position of the first bending section and the second bending section is the first pole; the other end of the second bending section is connected to one end of the third bending section, and the connection position of the second bending section and the third bending section is the second pole; the other section of the third bending section is connected to the linkage edge.

[0060] Compared with the traditional hexagonal unit cell structure, the triple double - pole ligament has an additional pair of ligament shape parameters a 2 and a 3 . By regulating the ligament shape parameters a 2 and a 3 , the mechanical properties, energy absorption characteristics and deformation degree of this honeycomb lattice structure can be regulated within a large range.

[0061] Among them, the honeycomb unit cells are connected up and down by sharing straight edges, and are connected on the left and right sides by the way of connecting through linkage edges, so as to form a honeycomb lattice structure by a plurality of honeycomb unit cells.

[0062] The overall honeycomb unit structure is a closed-loop linkage structure. Multiple honeycomb units form a honeycomb lattice structure, which are interconnected by linkage edges. Considering that the upper and lower parts of the honeycomb units share straight edges, when the entire honeycomb lattice structure is subjected to impact or tensile force, multiple honeycomb units can jointly handle the impact or torque.

[0063] This solution also proposes a regulation method for a cubic double-pole ligament negative Poisson's ratio honeycomb lattice structure, which is used for the cubic double-pole ligament negative Poisson's ratio honeycomb lattice structure and includes the following steps:

[0064] S1. Set parameter constraints, and the parameter constraints are limited as follows:

[0065] ;

[0066] ;

[0067] ;

[0068] ;

[0069] To meet the target geometric requirements, the main constraint condition stipulates that a 3 ≥ 0 and Δ > 0 to ensure the existence of two independent extreme points;

[0070] Here, x 1 and x 2 respectively represent the abscissas of the two extreme points of the function;

[0071] The secondary constraint condition requires that 0 < x 1 , x 2 < (l 1 - h 1 ) / 2, thereby limiting the extreme value coordinates within the design domain. At the same time, it is accompanied by the restrictions f(x 1 ) < h 2 / 2 and f(x 2 ) ≥ 0 to ensure compatibility;

[0072] Through the conditional equation a 1 = h 2 / (l 1 - h 1 ) – [a 2 (l 1 - h 1 )] / 2 – [a 3 (l 1 - h 1 )²] / 4, the continuity constraint at the structural node is achieved;

[0073] The honeycomb unit size includes a straight edge length of l 1 and a linkage edge spacing of h1 and the distance between the straight edges is h 2 and the thickness of the straight edge is t; a 1 a 2 a 3 are the three coefficients of the cubic function, and a 1 is obtained by calculating through the conditional formula, and a 2 and a 3 are input according to the requirements of Young's modulus and Poisson's ratio. The cubic function is defined as a polynomial function in the form of y = a 1 x + a 2 x 2 + a 3 x 3 . The coordinate origin is defined at the vertical center O point of the linkage edge. The positive x-axis direction is defined horizontally to the right along the linkage edge, and the positive y-axis direction is defined vertically upward perpendicular to the linkage edge. Since the cubic double-pole ligament passes through the coordinate origin O point, therefore a 0 = 0, where a 1 is the linear term coefficient, a 2 is the quadratic term coefficient, and a 3 is the cubic term coefficient;

[0074] S2. Input the honeycomb unit cell size and determine whether the honeycomb unit cell size parameters meet the parameter constraints. If the honeycomb unit cell size does not meet the parameter constraints, it needs to be adjusted and re-input;

[0075] S3. Predict Young's modulus and Poisson's ratio. If the unit cell size parameters meet the parameter constraints, substitute the honeycomb unit cell size data that meets the parameter constraints into the Young's modulus and Poisson's ratio prediction formulas to predict the Young's modulus and Poisson's ratio of the honeycomb unit cell with this data;

[0076] S4. Regulate Young's modulus and Poisson's ratio, and adjust the honeycomb unit cell size parameters used for prediction through the Young's modulus and Poisson's ratio regulation methods;

[0077] Adjustment of Young's modulus: increase h 2 ; or increase a 2 and decrease a 3 ; or decrease l 1 ; or increase t to increase Young's modulus; decrease h 2 ; or decrease a 2 and increase a 3 ; or increase l 1 ; or decrease t to reduce Young's modulus;

[0078] Regulation of Poisson's ratio: increase h 2 ; or increase a 2 and decrease a 3 ; or decrease l 1 ; or decrease h 1Enhance the negative Poisson's ratio effect by the method of; reduce h 2 ; or reduce a 2 and increase a 3 ; or increase l 1 ; or increase h 1 Reduce the negative Poisson's ratio effect by the method of.

[0079] Under quasi-static compression, it exhibits stable compressive deformation and gradually enhanced stress-strain behavior, significantly improving the energy absorption characteristics; it has excellent impact energy absorption and acceleration peak attenuation capabilities;

[0080] Among them; in step S3, the prediction formulas for the effective Young's modulus and Poisson's ratio of honeycomb unit cells under small deformations were derived using Castigliano's second theorem:

[0081] ;

[0082] ;

[0083] Among them, E y is the effective elastic modulus; v xy is the Poisson's ratio; E s is the elastic modulus of the base material.

[0084] Figure 4 It can be seen from that E y / E s is closely related to a 2 and a 3 . As a 3 decreases and a 2 increases, E y / E s increases; Figure 5 In, it can be seen that regardless of how the parameters change, the structure exhibits negative Poisson's ratio characteristics. a 2 and a 3 have an important influence on adjusting the magnitude of the Poisson's ratio. Reducing a 3 or increasing a 2 can both reduce the value of the Poisson's ratio; Figure 4-5 Shows that changing the numerical values of the ligament shape parameters a 2 and a 3 can significantly affect the elastic mechanical properties of the triple double-pole ligament negative Poisson's ratio honeycomb unit cell structure, thereby regulating the load-bearing capacity and energy absorption characteristics of the triple double-pole ligament negative Poisson's ratio honeycomb lattice structure.

[0085] Taking the triple double-pole ligament negative Poisson's ratio honeycomb lattice structure in Figure 3 as the object, quasi-static compression experiments and finite element simulations were carried out; Figures 6-8Shows the experimental and simulation results of a 4×3 dot matrix structure under different compression ratios. As compression progresses, the simulation and experimental results exhibit consistent deformation behavior. The simulation results accurately capture the deformation during the compression experiment, verifying the effectiveness of the simulation model.

[0086] Six different sets of ligament shape parameters are taken from Figure 4 and Figure 5 and named NAS-2-A to NAS-2-F. Finite element simulations are established for each of them. It can be seen that, compared with the traditional concave hexagonal dot matrix structure, as compression progresses, the cubic double-pole ligament negative Poisson's ratio honeycomb dot matrix structure exhibits self-contact enhancement, specifically manifested as a progressive strengthening stress-strain behavior. This phenomenon significantly improves the compression stability of the structure and enhances energy absorption, as shown in Figure 9 (b) in , verifying the superiority of the structure of this scheme.

[0087] The influence of different height parameters h 1 and h 2 on the mechanical properties and energy absorption of the cubic double-pole ligament negative Poisson's ratio honeycomb dot matrix structure. As can be seen from Figure 10 (a) in , when h 1 = 0.9, the ligaments of the unit cell intersect at a point, and its compression deformation mode is similar to that of a triangular dot matrix structure, specifically manifested as a high initial peak and a short plateau. As h 1 increases, its initial stress peak gradually decreases, and the unit cell gradually widens, having a larger concave deformation space, so the plateau gradually becomes longer. For the energy absorption situation, as shown in Figure 10 (b) in , since a small h 1 has a large stress level, as h 1 increases, the energy absorption gradually decreases. From Figure 11 , it can be seen that the influence of h 2 on the structure performance is relatively consistent. As h 2 increases, both its load-bearing capacity and energy absorption situation gradually deteriorate.

[0088] To further illustrate the protective practicality of the proposed structure, the inventor established an impact simulation model as shown in Figure 12 . A protective structure with a mass of 30 kg is subjected to different initial impact velocity loads. By continuously monitoring and recording the response of the center point on the upper surface of the structure, the energy dissipation and buffering capabilities of four different honeycomb dot matrix structures are quantitatively evaluated, as shown in Figures 13-15 . In the acceleration response curve of Figure 13 (a)-15(a), it can be seen that for the new dot matrix structure (h 2 = 18, h 2 = 14, h 1= 0.9) has a higher energy dissipation efficiency than the traditional honeycomb structure (NAS-1-F) under impact loads. These innovative structures extend the impact buffering stage and greatly improve the buffering performance of protection applications. From Figure 13 (b)-15(b), it can be seen that although the energy absorption capabilities among the four honeycomb structures are not much different, as the impact energy increases, the three new designs consistently show significant improvements in reducing the peak acceleration. It is worth noting that the honeycomb structure with h 1 = 0.9 performs excellently in both impact energy absorption and peak acceleration attenuation, indicating its high impact buffering and energy absorption levels.

[0089] This solution also proposes a fin using the above-mentioned cubic double-pole ligament negative Poisson's ratio honeycomb lattice structure. This fin uses the cubic double-pole ligament negative Poisson's ratio honeycomb lattice structure as the blade structure, and one side of the blade structure is covered with an elastic water surface layer.

[0090] Using the entire cubic double-pole ligament negative Poisson's ratio honeycomb lattice structure as the fin blade, under the same pulling force, the honeycomb lattice structure will deform compared to the blade without honeycombs, increasing the area of the blade and improving the efficiency of water propulsion; in the case of the same weight, using the honeycomb lattice structure to make the fin blade as the blade skeleton can improve the efficiency of the blade's water propulsion.

[0091] The technical principle of the present invention has been described above in combination with specific embodiments. These descriptions are only for explaining the principle of the present invention and cannot be construed in any way as a limitation on the protection scope of the present invention. Based on the explanations herein, those skilled in the art can readily conceive of other specific embodiments of the present invention without creative efforts, and these embodiments will fall within the protection scope of the present invention.

Claims

1. A cubic bipolar ligament negative Poisson's ratio honeycomb lattice structure, characterized in that: It includes multiple honeycomb unit cells, and the multiple honeycomb unit cells are assembled in a linked manner with each other; The honeycomb unit cell includes two symmetrically arranged straight edges, and the two ends of the two straight edges are respectively connected to a cubic double-pole ligament. The four cubic double-pole ligaments are respectively symmetric, and the relative ends of the two cubic double-pole ligaments on the same side are connected to the linkage edge. The two linkage edges are symmetric to each other and are in the same plane; The two straight edges, the four cubic double-pole ligaments and the two linkage edges form a linked structure that is interconnected.

2. The cubic bipolar ligament negative Poisson's ratio honeycomb lattice structure according to claim 1, characterized in that: The cubic double-pole ligament is in an "N" shape and includes a first bending section, a first pole, a second bending section, a second pole and a third bending section; One end of the first bending section is connected to one end of the straight edge, and the other end is connected to one end of the second bending section. The position where the first bending section and the second bending section are connected is the first pole; the other end of the second bending section is connected to one end of the third bending section. The position where the second bending section and the third bending section are connected is the second pole; the other section of the third bending section is connected to the linkage edge.

3. The cubic bipolar ligament negative Poisson's ratio honeycomb lattice structure according to claim 2, characterized in that: The honeycomb unit cells are connected up and down by sharing straight edges, and are connected to each other on the left and right sides by the way of connecting the linkage edges, so that a plurality of honeycomb unit cells form a honeycomb lattice structure.

4. A control method for a cubic bipolar ligament negative Poisson's ratio honeycomb lattice structure, characterized in that: This method is used for the cubic double-pole ligament negative Poisson's ratio honeycomb lattice structure described in claim 3; it includes the following steps: S1. Set parameter constraints, and the parameter constraints are limited as follows: ； ； ； ； To meet the target geometric requirements, the main constraint conditions stipulate that a3>0 and Δ>0 to ensure the existence of two independent extreme points; Here, x1 and x2 respectively represent the abscissas of the two extreme points of the function; The secondary constraint conditions force 0<x1,x2<(l1-h1) / 2, so as to limit the extreme value coordinates within the design domain range, and at the same time accompany the restrictions f(x1)<h2 / 2 and f(x2)≥0 to ensure compatibility; The continuity constraint at the structural node is realized through the conditional formula a1=h2 / (l1-h1)–[a2(l1-h1)] / 2–[a3(l1-h1)²] / 4; The dimensions of the honeycomb unit cell include the straight edge length l1, the linkage edge spacing h1, the straight edge spacing h2, and the straight edge thickness t; a1, a2, and a3 are the three coefficients of the cubic function, a1 is calculated by the conditional formula, and a2 and a3 are input according to the requirements of Young's modulus and Poisson's ratio. The cubic function is defined as y=a1x+a2x 2 +a3x 3 The polynomial function defines the origin of the coordinate system at the vertical center O of the linkage edge, the horizontal rightward direction along the linkage edge is defined as the positive direction of the x-axis, and the vertical upward direction perpendicular to the linkage edge is defined as the positive direction of the y-axis; S2. Input the honeycomb unit cell size, and judge whether the honeycomb unit cell size parameters meet the parameter constraints. If the honeycomb unit cell size does not meet the parameter constraints, it needs to be adjusted and re-input; S3. Prediction of Young's modulus and Poisson's ratio. If the unit cell size parameters meet the parameter constraints, substitute the honeycomb unit cell size data that meets the parameter constraints into the Young's modulus and Poisson's ratio prediction formulas to predict the Young's modulus and Poisson's ratio of the honeycomb unit cell of this data; S4. Regulation of Young's modulus and Poisson's ratio. Adjust the honeycomb unit cell size parameters used for prediction through the Young's modulus and Poisson's ratio regulation method; Adjustment of Young's modulus. Increase Young's modulus by increasing h2; or increasing a2 and decreasing a3; or decreasing l1; or increasing t; decrease Young's modulus by decreasing h2; or decreasing a2 and increasing a3; or increasing l1; or decreasing t; Regulation of Poisson's ratio. Increase the effect of negative Poisson's ratio by increasing h2; or increasing a2 and decreasing a3; or decreasing l1; or decreasing h1; decrease the effect of negative Poisson's ratio by decreasing h2; or decreasing a2 and increasing a3; or increasing l1; or increasing h1.

5. The control method of the cubic bipolar ligament negative Poisson's ratio honeycomb lattice structure according to claim 4, characterized in that; In step S3, Castigliano's second theorem is used to derive the prediction formulas for the effective Young's modulus and Poisson's ratio of the honeycomb unit cell under small deformation: ； ； Among them, E y is the effective elastic modulus; v xy is Poisson's ratio; E s The elastic modulus of the parent material.

6. A flipper using the above-mentioned cubic bipolar ligament negative Poisson's ratio honeycomb lattice structure, characterized in that: The device uses the cubic double-pole ligament negative Poisson's ratio honeycomb lattice structure described in any one of claims 1 to 3 as a blade structure, and one side of the blade structure is covered with an elastic paddling surface layer.

Images