Chiral-rotating rigid body coupled negative poisson's ratio structure

Abstract

The application provides a chiral-rotating rigid body coupled negative Poisson's ratio structure, and relates to the technical field of mechanical metamaterials. The structure comprises a plurality of combined unit cells, the plurality of combined unit cells are periodically arranged along a planar direction and integrally connected to form a whole structure, and an outer boundary of the whole structure is provided with a peripheral support frame. Each combined unit cell comprises a rotating rigid body unit, a left-handed negative Poisson's ratio unit and a flexible connecting ligament, the rotating rigid body unit is arranged in a central region of the unit cell, and the rotating rigid body unit and the left-handed negative Poisson's ratio unit are integrally connected to a composite structure through the flexible connecting ligament. The application couples the negative Poisson's ratio effect through the dual deformation mechanisms of rigid rotation and flexible bending, can effectively improve the deformation stability and energy absorption capacity of the structure, and is suitable for the fields of aerospace protection, rail transit energy absorption, automobile collision prevention and the like.

Description

Technical Field

[0001] This application relates to the field of mechanical metamaterials technology, and in particular to a chiral-rotational rigid body coupled negative Poisson's ratio structure. Background Technology

[0002] In recent years, dilatational metamaterials exhibiting the negative Poisson's ratio (NPR) effect have become a research hotspot in the field of mechanical metamaterials due to their unique deformation behavior and excellent mechanical properties. NPR materials expand laterally under longitudinal tension and contract laterally under longitudinal compression, exhibiting deformation characteristics diametrically opposite to those of conventional materials. This anomalous behavior endows them with numerous superior mechanical properties: high shear modulus, high resistance to indentation, high fracture toughness, and excellent energy absorption capacity.

[0003] Chiral auxetic structures, first proposed by Lakes in 1987, are characterized by the coupling of rotation at the central node and bending deformation of the tangential ligament to achieve a negative Poisson's ratio effect. Typical chiral structures include trichiral, tetrachiral, and hexachiral configurations, and can be further classified into syn-chiral and anti-chiral types based on the direction of ligament connection. The advantages of chiral structures lie in their near-isotropic mechanical properties, smooth stress-strain response, and excellent stability under dynamic loading.

[0004] Rotational Rigid-body Auxetic Structures (RRBs) were systematically proposed by GRIMAL et al. in 2000. Their core mechanism involves macroscopic contraction achieved through the relative rotation of rigid polygonal elements (such as squares, rectangles, and triangles) around flexible hinge points. These structures possess advantages such as high initial stiffness, significant negative Poisson's ratio effect (theoretically close to -1), and small boundary effects.

[0005] Both structures have limitations: chiral negative Poisson's ratio structures, whose deformation mainly depends on ligament bending, have low overall stiffness and limited platform stress levels, making them unsuitable for applications requiring high load-bearing capacity and high energy absorption. Furthermore, traditional chiral structures are prone to ligament contact failure under large deformations, limiting their efficiency as energy-absorbing structures. Rotational rigid body structures have inherent defects: because their constituent units are rigid, once the hinges are fully closed, the structure rapidly solidifies and loses its deformability, severely limiting its application in large deformation energy absorption. Summary of the Invention

[0006] This application provides a chiral-rotational rigid body coupled negative Poisson's ratio structure. By integrating rotational rigid body negative Poisson's ratio elements with anti-crank negative Poisson's ratio elements, a dual negative Poisson's ratio deformation mechanism is formed within the same cell. The rotational rigid body elements provide high initial load-bearing capacity, while the anti-crank elements provide continuous bending deformation capacity. The two deformation modes are coupled with each other, enabling the structure to achieve stable and progressive deformation during compression, reducing local stress concentration, delaying structural failure, and improving specific energy absorption, plateau stress stability, and overall mechanical properties.

[0007] To achieve the above objectives, this application adopts the following technical solution: This application provides a chiral-rotational rigid body coupled negative Poisson's ratio structure, comprising multiple combined unit cells, which are periodically arrayed along a planar direction and integrally connected to form an integral structure, wherein an outer support frame is provided on the outer boundary of the integral structure; Each of the composite unit cells includes a rotational rigid body unit, a reverse-hand negative Poisson's ratio unit, and a flexible connecting ligament. The rotational rigid body unit is located in the central region of the unit cell. The rotational rigid body unit and the reverse-hand negative Poisson's ratio unit are integrally connected by the flexible connecting ligament to form a composite structure. When under pressure, the negative Poisson's ratio effect is generated through the coupling of a dual deformation mechanism of rigid rotation and flexible bending.

[0008] Preferably, in the above-mentioned chiral-rotational rigid body coupled negative Poisson's ratio structure, the rotational rigid body unit includes a rigid polygonal frame. Multiple rigid polygonal frames are centrally symmetrically distributed around the center of the unit cell and enclose a hollow area located at the center of the unit cell. The corners of adjacent rigid polygonal frames are connected by flexible hinges. When compressed, each rigid polygonal frame rotates relative to the flexible hinge, providing initial load-bearing stiffness for the structure.

[0009] Preferably, in the above-mentioned chiral-rotational rigid body coupled negative Poisson's ratio structure, the anti-chiral negative Poisson's ratio unit includes circular nodes and inclined ligaments; multiple circular nodes are symmetrically arranged along multiple diagonal positions of the unit cell, and adjacent circular nodes are integrally connected by the inclined ligaments. When compressed, the inclined ligaments undergo bending deformation and continuously absorb external load energy.

[0010] Preferably, in the above-described chiral-rotational rigid body coupled negative Poisson's ratio structure, the geometry of the combined unit cell is determined by four basic geometric parameters, namely the ligament wall thickness. Hollowed-out rigid body wall thickness Radius of the central circle and ligament length Wherein, the ligament wall thickness The thickness of the inclined ligament, and the wall thickness of the hollow rigid body. The wall thickness of the rigid polygonal frame and the radius of the central circle are given. The radius of the circular node, the length of the ligament The distance from the center of the circular node to the center of the unit cell; The rhomboid dimensions of the hollowed-out region inside the unit cell satisfy the following relationship: In the formula, The half-length dimension of the rhomboid hollow area along the diagonal of the unit cell. The width of the diamond-shaped cutout area is perpendicular to the diagonal direction.

[0011] Preferably, in the above-described chiral-rotational rigid body coupled negative Poisson's ratio structure, the tilt angle of the rigid polygonal frame is... satisfy: The lateral side length of the combined unit cell With longitudinal side length The following relationship must be satisfied: Multiple combined unit cells are arranged in a continuous, tightly packed n*n matrix along the X and Y directions and integrally formed to create a two-dimensional periodic metamaterial structure, where n is a positive integer greater than or equal to 2; the overall length of the two-dimensional periodic metamaterial structure is... Overall width The following relationship must be satisfied: .

[0012] Preferably, in the above-mentioned chiral-rotational rigid body coupled negative Poisson's ratio structure, a thickness scaling factor is set. Geometric Dimension Scale ,in: The thickness ratio coefficient Used to adjust the stiffness distribution between the rotating rigid body element and the anti-handed negative Poisson's ratio element; the geometric dimension scaling factor Used to regulate the tilt angle and deformation range of unit cells.

[0013] Preferably, in the above-described chiral-rotational rigid body coupled negative Poisson's ratio structure, the relative density of the combined unit cell is... With porosity The following relationship must be satisfied: In the formula, For the volume of the structural entity, The volume of the outer envelope of a single cell; the relative density With thickness scaling factor and geometric dimension scaling factor It changes with the changes.

[0014] Preferably, in the above-described chiral-rotational rigid body coupled negative Poisson's ratio structure, the thickness scaling factor is adjusted. proportionality coefficient of the geometric dimensions To regulate the stiffness distribution, deformation mode, and energy absorption performance of the structure: Increase the thickness ratio coefficient The increased relative thickness of the inclined ligament enhances the overall energy absorption effect of the structure; increasing the geometric dimension ratio coefficient... The radius of the circular node is relatively increased, and the tilt angle of the rigid polygonal frame is... As the rotational stroke of the rigid body decreases, the compression stroke of the circular ring increases, resulting in enhanced energy absorption in the later stages of the structure, but a weakening of the negative Poisson's ratio effect.

[0015] Preferably, in the above-described chiral-rotational rigid body coupled negative Poisson's ratio structure, the two-dimensional periodic metamaterial structure extends along the Z-axis direction with a predetermined thickness. L Z This forms a three-dimensional blocky metamaterial structure.

[0016] Preferably, in the above-described chiral-rotational rigid body coupled negative Poisson's ratio structure, during compressive loading, the structure sequentially undergoes the following deformation stages: During the initial compression phase, the rigid polygonal frame of the rotating rigid body unit rotates relative to the flexible hinge, providing initial load-bearing stiffness for the structure. During the continued compression phase, the tilted ligament of the reverse-hand negative Poisson's ratio unit undergoes bending deformation, continuously absorbing external load energy; In the further compaction stage, the hollow areas inside the unit cell come into contact with and are squeezed against the inner wall of the circular node, which again provides support and achieves multi-stage progressive energy dissipation.

[0017] The chiral-rotational rigid body coupled negative Poisson's ratio structure provided in this application has at least the following beneficial effects: Compared with existing single anti-poisson ratio structures and rotating rigid body negative Poisson ratio structures, this application integrates the rigid rotation mechanism of the rotating rigid body element with the flexible bending mechanism of the anti-poisson ratio element, enabling the two different deformation modes to work together in the same structural element, thereby achieving an effective balance between load-bearing capacity and deformation capacity.

[0018] In this composite structure, the rotating rigid body elements provide high initial load-bearing stiffness, while the anti-handed negative Poisson's ratio elements absorb external load energy through the continuous bending deformation of the inclined ligaments. Together, these elements enable the structure to exhibit progressively stable deformation characteristics during compression. The introduction of the anti-handed negative Poisson's ratio elements slows down the rapid densification process of the rotating rigid body structure due to element contact, reduces local stress concentration, and significantly improves the deformation stability of the structure. While maintaining a high load-bearing capacity, the cumulative energy absorption and specific energy absorption of this composite structure are superior to those of a single structure, enabling it to dissipate external impact energy more effectively.

[0019] Furthermore, the geometry of this structure is controlled by four basic geometric parameters: ligament wall thickness, hollow rigid body wall thickness, central circle radius, and ligament length. Stiffness, negative Poisson's ratio effect, and energy absorption performance can be flexibly adjusted by modifying the thickness and geometric dimension ratios to meet the needs of different engineering scenarios. The overall structure is suitable for integral molding using additive manufacturing processes, resulting in a simple manufacturing process and promising engineering application prospects. Attached Figure Description

[0020] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0021] Figure 1 A three-dimensional structural diagram of a chiral-rotational rigid body coupled negative Poisson's ratio structure provided in an embodiment of this application; Figure 2 A plan view of a composite unit cell in a chiral-rotational rigid body coupled negative Poisson's ratio structure provided in an embodiment of this application; Figure 3 This application provides a schematic diagram of a combined structure of a chiral-rotational rigid body coupled negative Poisson's ratio structure. Figure 4 This application provides an embodiment of a combined structural compression cell deformation process for a chiral-rotational rigid body coupled negative Poisson's ratio structure. Figure 5 The combined structural cell parameters of a chiral-rotational rigid body coupled negative Poisson's ratio structure from a planar perspective are provided in the embodiments of this application. Figure 6 The combined structural cell parameters of a chiral-rotational rigid body coupled negative Poisson's ratio structure in a three-dimensional view are provided in the embodiments of this application. Figure 7 A schematic diagram of the structure of the printed specimen provided in the embodiments of this application; wherein, (a) test specimen; (b) standard tensile specimen; (c) schematic diagram of tensile test; (d) finite element mesh model of the combined structure; Figure 8 This is a schematic diagram of the DIC measuring point layout provided in an embodiment of this application; Figure 9 Comparison diagrams of deformation and failure evolution of different structures during quasi-static compression processes provided in the embodiments of this application; wherein, (a) ATC; (b) ATC-RRS; (c) RRS; Figure 10 Stress-strain curves and cumulative energy absorption curves for different structures provided in the embodiments of this application: (a) stress-strain curve; (b) cumulative energy absorption curve; Figure 11 The strain cloud diagrams of the combined structure under different α conditions provided in the embodiments of this application are shown; wherein, (1)-(5) correspond to five discrete specimens with α values ​​of 0.5, 0.8, 1.0, 1.25 and 2.0 respectively; Figure 12 A schematic diagram illustrating the effect of the α parameter on the compressive mechanical properties and Poisson's ratio of the structure, provided for embodiments of this application: where (a) is the stress-strain curve; and (b) is the Poisson's ratio-strain curve. Figure 13 The stress-strain response curves of the combined structure under different β conditions provided in the embodiments of this application; wherein, (1)-(5) correspond to five groups of discrete specimens with β values ​​of 0.3, 0.4, 0.5, 0.6 and 0.7 respectively; Figure 14 The stress-strain response curves of the combined structure under different β conditions provided in the embodiments of this application are as follows: (a) stress-strain curve; (b) Poisson's ratio-strain curve.

[0022] Figure label: 1. Rotational rigid body element; 2. Reverse-hand negative Poisson's ratio element; 3. Flexible connecting ligament; 4. External support frame; 11. Rigid polygonal frame; 12. Hollowed-out area; 13. Flexible hinge; 21. Circular node; 22. Inclined ligament.

[0023] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concepts of this application to those skilled in the art through reference to specific embodiments. Detailed Implementation

[0024] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0025] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0026] This application provides a chiral-rotational rigid body coupled negative Poisson's ratio structure, suitable for engineering fields requiring lightweight, high strength, and efficient energy absorption, such as aerospace, rail transportation, automotive crash protection, personal protective equipment, packaging cushioning, and building impact resistance. This structure can be manufactured using materials such as nylon, resin, and metal, or processed using additive manufacturing processes such as selective laser sintering (SLS) and fused deposition modeling (FDM). This chiral-rotational rigid body coupled negative Poisson's ratio structure introduces both rotational rigid body elements and anti-chiral elements within the same structural unit, enabling the structure to simultaneously possess both rigid rotation and flexible bending deformation mechanisms during compression. This design helps to disperse localized stress concentrations and delays structural failure while maintaining a certain load-bearing capacity, thereby achieving synergistic optimization of structural performance.

[0027] In this embodiment, rigid rotation refers to the relative rotational motion of the rotating rigid body unit 1 around the flexible hinge 13 under the action of external force, which provides the initial load-bearing stiffness of the structure. Flexible bending refers to the bending deformation of the inclined ligament 22 of the anti-handed negative Poisson's ratio unit 2 under the action of external force, which can continuously absorb external load energy. The negative Poisson's ratio effect refers to the anomalous deformation characteristic of a material that contracts laterally during longitudinal compression. This application achieves this effect through the coupling and synergy of two deformation mechanisms: rigid rotation and flexible bending. By combining two different deformation mechanisms, this application enables the combined structure to possess both the high initial load-bearing capacity of the rotating rigid body unit and the continuous bending deformation characteristics of the anti-handed negative Poisson's ratio unit. It has a more stable progressive deformation capability during compression, while delaying the rapid densification process of the rotating rigid body structure due to unit contact, reducing local stress concentration, and improving deformation stability.

[0028] like Figure 1 and Figure 2 As shown, the chiral-rotational rigid body coupled negative Poisson's ratio structure includes multiple composite unit cells. These composite unit cells are periodically arrayed along the planar direction and integrally connected to form an overall structure. An outer support frame 4 is provided at the outer boundary of the overall structure. Each composite unit cell includes a rotational rigid body element 1, a reverse-handed negative Poisson's ratio element 2, and a flexible connecting ligament 3. The rotational rigid body element 1 is located in the central region of the unit cell. The rotational rigid body element 1 and the reverse-handed negative Poisson's ratio element 2 are integrally connected to form a composite structure through the flexible connecting ligament 3. Under pressure, the negative Poisson's ratio effect is generated through the coupling of a dual deformation mechanism of rigid rotation and flexible bending.

[0029] In this embodiment, the outer support frame 4 is located at the outer boundary of the overall structure. Its function is to constrain and support the internal periodic unit cell structure, ensuring the boundary integrity of the overall structure under load. Flexible connecting ligaments 3 connect the rotating rigid body unit 1 and the anti-handed negative Poisson's ratio unit 2 within the same unit cell, enabling them to form a co-deformable whole. For example, the overall dimensions of the structure can be adjusted according to actual application requirements. For instance, the overall length and width can be set to 62mm, and the height to 20mm to meet the testing requirements of quasi-static compression experiments. It can also be enlarged or reduced according to actual engineering needs. This structure can be integrally formed using additive manufacturing processes, avoiding errors and performance uncertainties caused by secondary assembly.

[0030] In some embodiments, such as Figure 3 and Figure 4 As shown, the rotating rigid body unit 1 includes a rigid polygonal frame 11. Multiple rigid polygonal frames 11 are centrally symmetrically distributed around the center of the unit cell and enclose a hollow area 12 located at the center of the unit cell. The corners of adjacent rigid polygonal frames 11 are connected by flexible hinges 13. When under pressure, each rigid polygonal frame 11 rotates relative to the flexible hinge 13, providing initial load-bearing stiffness for the structure.

[0031] In this embodiment, the rigid polygonal frame 11 refers to a frame-like structure with a polygonal outline made of rigid material. Its shape is not limited to a specific polygon and can be a quadrilateral, rhombus, or other geometric shape capable of relative rotation. The flexible hinge 13 refers to a connection area with a certain degree of flexibility. The stiffness of this area is lower than that of the rigid polygonal frame 11, allowing the rigid polygonal frame 11 to rotate relative to the flexible hinge 13 under external force. The flexible hinge 13 and the rigid polygonal frame 11 are integrally formed through additive manufacturing, requiring no additional assembly. Its flexibility is achieved by locally reducing the wall thickness or adjusting the material density. For example, when the structure is subjected to a longitudinal compressive load, each rigid polygonal frame 11 rotates inward around the flexible hinge 13, causing the entire unit cell to contract laterally, thereby generating a negative Poisson's ratio effect. This rotation mechanism gives the structure a high initial load-bearing stiffness, enabling the structure to withstand a large load in the early stages of deformation.

[0032] In some embodiments, such as Figure 3 and Figure 4 As shown, the reverse-hand negative Poisson's ratio element 2 includes circular nodes 21 and inclined ligaments 22; multiple circular nodes 21 are symmetrically arranged along multiple diagonal positions of the unit cell, and adjacent circular nodes 21 are integrally connected by inclined ligaments 22. When compressed, the inclined ligaments 22 bend and deform and continuously absorb external load energy.

[0033] In this embodiment, the circular node 21 refers to the circular rigid region located diagonally across the unit cell, serving to connect the inclined ligament 22 and transfer loads. The inclined ligament 22 refers to the inclined ligament structure connecting adjacent circular nodes 21, which absorbs external load energy through bending deformation under compression. The anti-handed negative Poisson's ratio unit 2 itself is a four-ligament anti-handed negative Poisson's ratio structure, which generates a negative Poisson's ratio effect through the coupling of the rotation of the circular nodes 21 and the bending deformation of the inclined ligament 22. Exemplarily, when the composite unit cell is subjected to compressive load, the inclined ligament 22 undergoes bending deformation. This bending deformation can continue within a large strain range, enabling the structure to maintain stable load-bearing capacity and energy absorption capacity over a long deformation stroke. The bending deformation mechanism of the inclined ligament 22 and the rigid rotation mechanism of the rotating rigid body unit 1 complement each other in their working sequence. The rotating rigid body unit 1 bears the load first in the initial stage of deformation, while the inclined ligament 22 continues to play a role in the subsequent deformation process.

[0034] In some embodiments, such as Figure 5 As shown, the geometry of the composite unit cell is determined by four basic geometric parameters, namely the ligament wall thickness. Hollowed-out rigid body wall thickness Radius of the central circle and ligament length Among them, ligament wall thickness The thickness of the inclined ligament 22, and the wall thickness of the hollow rigid body. The wall thickness and center circle radius of the rigid polygonal frame 11 are given. The radius of circular node 21, ligament length It is the distance from the center of circular node 21 to the center of the unit cell.

[0035] The rhomboid dimensional parameters of the hollowed-out region 12 inside the unit cell satisfy the following relationship: In the formula, The half-length dimension of the rhomboid hollow area along the diagonal of the unit cell. The width of the diamond-shaped cutout area is perpendicular to the diagonal direction.

[0036] In this embodiment, four basic geometric parameters , , , The geometric configuration of the unit cell is determined by these four basic parameters, and all other geometric parameters are derived from them. The rhomboid hollow region 12 refers to the rhomboid gap located at the center of the unit cell, formed by four rigid polygonal frames 11. The region size parameters... and This reflects the size and shape of the cut-out area. For example, when... When fixed, Increasing the size means increasing the radius of the circular node 21 and the size of the hollow area 12. As the dimensions increase accordingly, the geometry of the unit cell changes. The setting of these four basic geometric parameters provides the structure with flexible design space, allowing it to be adapted to different performance requirements by adjusting these parameters. For example, for applications requiring higher load-bearing capacity, the dimensions can be appropriately increased. The wall thickness of the rigid polygonal frame 11 can be increased; for applications requiring greater deformation capacity, the thickness can be adjusted appropriately. and The value of is used to change the geometry of the unit cell.

[0037] In some embodiments, such as Figure 5 As shown, the tilt angle of the rigid polygonal frame 11 satisfy: lateral side length of the composite unit cell With longitudinal side length The following relationship must be satisfied: like Figure 6 As shown, multiple combined unit cells are arranged in a continuous and compact n*n matrix along the X and Y directions and integrally formed to create a two-dimensional periodic metamaterial structure, where n is a positive integer greater than or equal to 2; the overall length of the two-dimensional periodic metamaterial structure is... Overall width The following relationship must be satisfied: .

[0038] A two-dimensional periodic metamaterial structure is extended along the Z-axis with a set thickness. L Z This forms a three-dimensional blocky metamaterial structure.

[0039] In this embodiment, the tilt angle of the rigid polygonal frame 11 This refers to the azimuth angle of the rigid polygonal frame 11 within the unit cell, which is determined by geometric parameters. and The ratio is determined by this. When When the angle is larger, the node twist angle is greater, and the node energy absorption effect is better; when When the value is small, the rigid body rotation angle decreases while the circular ring compression stroke increases. Continuous close arrangement refers to adjacent unit cells being directly adjacent without gaps; this arrangement ensures the integrity of the structure and the continuity of load transfer. For example, when n=2, the overall structure consists of 2×2=4 unit cells, and the overall length... =8 When n=3, the overall structure consists of 3×3=9 unit cells. For example, for quasi-static compression experiments, an array structure with n=4 can be used, along with upper and lower loading plates. The structure can also select the value of n according to actual engineering needs and be integrally formed through additive manufacturing. The thickness of this three-dimensional blocky metamaterial structure... L Z It can be set according to the actual application requirements. For example, it can be set to a thickness equivalent to the in-plane dimension to form a cubic structure, or it can be set to a thinner thickness to form a plate-like structure.

[0040] In some embodiments, a thickness scaling factor is set. Geometric Dimension Scale ,in: Thickness ratio factor Used to adjust the stiffness distribution between the rotating rigid body element 1 and the anti-handed negative Poisson's ratio element 2; geometric dimension scaling factor. Used to regulate the tilt angle and deformation range of unit cells.

[0041] In this embodiment, the thickness scaling factor This thickness ratio factor reflects the wall thickness ratio between the inclined ligament 22 and the rigid polygonal frame 11. It affects the stiffness distribution within the structure. When When the relative thickness of the inclined ligament 22 increases, the flexible bending stiffness of the reverse-hand negative Poisson's ratio element 2 increases; when When the relative thickness is smaller, the relative thickness of the rigid polygonal frame 11 increases, and the rigid rotational stiffness of the rigid body element 1 increases. Geometric dimension scaling factor. This geometrical proportionality coefficient reflects the ratio between the radius of the circular node 21 and the length of the ligament. This directly affects the geometry and deformation pattern of the unit cell. For example, designers can adjust the geometry and deformation pattern according to specific application requirements. and The value of can be reduced for applications requiring higher initial load-bearing stiffness. Increase the relative thickness of the rigid polygonal frame 11; for applications requiring greater energy absorption capacity, the thickness can be adjusted. To optimize deformation stroke and energy absorption path.

[0042] In some embodiments, the relative density of the combined unit cell With porosity The following relationship must be satisfied: In the formula, For the volume of the structural entity, Volume of the outer envelope of a single cell; relative density With thickness scaling factor and geometric dimension scaling factor It changes with the changes.

[0043] In this embodiment, relative density Refers to the volume of the structural entity With the volume of the outer envelope of a single cell The ratio of porosity to solid material, which reflects the proportion of solid material in the structure. Relative density refers to the percentage of void volume within a structure relative to the volume of its outer envelope; this percentage reflects the porosity of the structure. and porosity Both describe the degree of lightweighting of the structure, and their sum is 1. Relative density along with and It changes with the changes, because , , , Changes will directly affect the volume of the structural entity. and the volume of the outer envelope of a single cell For example, when When =1, = The structural entity has a relatively large volume and a relatively high density. High porosity Lower; when A deviation from 1, whether increasing or decreasing, implies that the thickness of some components is weakened, the volume of the structural entity decreases, and the relative density decreases. Reduce porosity Increase. For example, relative density. The volume of a structural entity can be obtained through the mass properties of 3D modeling software. It can be calculated later, or it can be determined by weighing combined with material density experiments.

[0044] In some embodiments, by adjusting the thickness scaling factor Geometric Dimension Scale To regulate the stiffness distribution, deformation mode, and energy absorption performance of a structure: increase the thickness proportionality coefficient. The increased relative thickness of the inclined ligament 22 enhances the overall energy absorption effect of the structure; the increased geometric dimension ratio also contributes to this effect. The radius of the circular node 21 is relatively increased, and the tilt angle of the rigid polygonal frame 11 is increased. As the rotational stroke of the rigid body decreases, the compression stroke of the circular ring increases, resulting in enhanced energy absorption in the later stages of the structure, but a weakening of the negative Poisson's ratio effect.

[0045] In this embodiment, stiffness distribution refers to the stiffness ratio between the rotating rigid body element 1 and the anti-handed negative Poisson's ratio element 2. When As the wall thickness of the inclined ligament 22 increases relative to the wall thickness of the rigid polygonal frame 11, the bending stiffness of the reverse-hand negative Poisson's ratio element 2 increases, and the structure absorbs more energy through the bending deformation of the inclined ligament 22 in the later stages of compression, thus enhancing the overall energy absorption effect. When the radius of circular node 21 increases, Relative to ligament length Increase the tilt angle of the rigid polygonal frame 11 The corresponding reduction decreases the rotational stroke of the rigid body while increasing the compression stroke of the circular node 21. During the later compaction stage, the structure absorbs more energy through the contact compression between the hollow region 12 and the inner wall of the circular node 21. For example, in applications requiring a higher negative Poisson's ratio, the reduction can be appropriately made. To increase This results in a more significant negative Poisson's ratio effect; for applications requiring higher energy absorption capacity, the ratio can be appropriately increased. To enhance the energy absorption effect of the subsequent annular compression. For example, The value can range from 0.3 to 0.7. The value can range from 0.5 to 2.0, and the specific value can be determined through finite element simulation optimization based on the target performance.

[0046] In some embodiments, during the compression loading process, the structure undergoes the following deformation stages sequentially: During the initial compression stage, the rigid polygonal frame 11 of the rotating rigid body unit 1 rotates relative to the flexible hinge 13, providing initial load-bearing stiffness for the structure. During the continued compression phase, the inclined ligament 22 of the reverse negative Poisson's ratio element 2 undergoes bending deformation, continuously absorbing external load energy; In the further compaction stage, the hollow area 12 inside the unit cell comes into contact with and is squeezed by the inner wall of the circular node 21, which once again provides support and achieves multi-stage progressive energy dissipation.

[0047] In this embodiment, multi-stage progressive energy dissipation refers to the structure undergoing multiple different deformation modes sequentially during compression, each corresponding to a different energy absorption mechanism, thereby achieving stable energy absorption throughout the process. The initial compression stage corresponds to the initial strain stage, at which point the rigid polygonal frame 11 of the rotating rigid body unit 1 bears the load and provides high initial stiffness, giving the structure strong compressive strength from the start of deformation. The continued compression stage corresponds to the middle strain stage, at which point the inclined ligament 22 begins to bend and deform. This bending deformation can continue within a large strain range, buffering local stress at the connection points of the rotating rigid body unit 1 and delaying structural failure. The further compaction stage corresponds to the later strain stage, at which point the internal voids of the structure are gradually compressed and closed, and the hollow area 12 and the inner wall of the circular node 21 come into contact and compress each other, again providing support. For example, for a composite structure made of nylon material using the SLS process, the initial compression stage corresponds to approximately 0-5% of the strain range, the continued compression stage corresponds to approximately 5%-40% of the strain range, and the further compaction stage corresponds to a strain range of over 40%. For example, under a quasi-static compression test with a loading rate of 2 mm / min, the deformation evolution and strain distribution in the above three stages can be observed using a universal testing machine in conjunction with DIC technology. This multi-stage progressive energy dissipation mechanism enables the composite structure to achieve the highest cumulative energy absorption among the three comparative structures, improving by 42.82% and 33.25% respectively compared to the single rotating rigid body structure and the anti-handed structure.

[0048] The specific parameter values, material selections, process conditions, and experimental conditions described in the above embodiments are merely illustrative and do not constitute a limitation on the scope of protection of this application. Those skilled in the art can adjust and optimize the above parameters according to actual engineering needs and application scenarios, all of which fall within the scope of protection of this application.

[0049] To further illustrate the feasibility and advancement of this chiral-rotational rigid body coupled negative Poisson's ratio structure, two specific examples will be used to explain it in detail below.

[0050] Example 1: Brittleness Comparison Test To investigate the mechanical properties of structures with different negative Poisson's ratios, three typical configurations—chiral structures, rigid bodies of rotation, and composite structures—were selected for comparative analysis. All structures adopted a uniform external dimension design, with overall specimen dimensions of 62 mm × 60 mm × 20 mm to ensure good comparability between different structures. Printing materials such as... Figure 7As shown in (a), GFPA12 nylon powder was used, and the printing method was selective laser sintering (SLS). The powder bed temperature was 170℃, the chamber temperature was 150℃, the laser power was 45W, and the scanning speed was 500mm / s. The parameters of the printed specimen are shown in Table 1. To ensure uniform load distribution on the structural surface during compression and to avoid stress concentration caused by local contact, a 60mm long, 20mm wide, and 1mm thick plate was added to the top and bottom of the specimen. The basic parameters of the three experimental specimens are shown in Table 1.

[0051] Table 1 3D Printing Material Parameters

[0052] Printed test pieces, such as Figure 7 As shown in (a), Figure 7 (b) Five standard specimens were prepared according to GB / T1040.1-2018, the standard for determination of tensile properties of plastics. For example... Figure 7 As shown in (c), a tensile test was conducted on the specimen structure using an MTS Exceed E45 electronic universal testing machine. Displacement-controlled loading was employed according to the standard, with a loading rate of 1 mm / min. Force-displacement data were collected during the compression failure process, and nominal stress-strain curves were plotted. Material parameters were then determined for finite element simulation analysis. Figure 7 (b) Five standard specimens were prepared in accordance with GB / T1040.1-2018 standard for determination of tensile properties of plastics.

[0053] To obtain the deformation characteristics of the structure during compression, digital image correlation (DIC) technology was used to measure the surface displacement of the specimen. For example... Figure 8 As shown, feature tracking points are arranged at key structural nodes, with a focus on selecting unit connection areas and locations with significant geometric changes to improve the sensitivity and accuracy of deformation measurement.

[0054] By tracking the displacement changes of each measuring point during the loading process, the axial and lateral displacements are extracted separately, thereby calculating the axial and lateral strains of the structure and further obtaining Poisson's ratio. This method can also be used in Abaqus software to track point displacements and calculate Poisson's ratio. To ensure the representativeness of the measurement results, the measuring points are symmetrically distributed on the structural surface, covering multiple unit areas to reduce the influence of errors caused by local deformation. The average displacement between the top and bottom rows of the markers is considered the axial displacement, while the average displacement between the left and right columns of the markers is considered the lateral displacement. The actual axial and lateral strains are then calculated accordingly.

[0055] The formula for calculating Poisson's ratio is as follows: Where ε x(a-r)ε represents the transverse strain between measuring points a and r. y（g-j） This represents the longitudinal strain between measuring points g and j; the rest are similar.

[0056] Three specimens were subjected to static compression treatment on a testing machine. During the compression process, the specimens underwent varying degrees of brittle fracture deformation and the moment of failure, as shown in the figure. Figure 9 As shown, the damage mainly occurs at the ligament center and rigid body connection.

[0057] The three structures exhibited significant differences in deformation and failure modes during quasi-static compression. The composite structure and the chiral structure both underwent relatively continuous deformation evolution, while the rotating rigid body structure showed significant instability at a small displacement, indicating more pronounced local stress concentration and a relatively short stable deformation range. The chiral structure, on the other hand, demonstrated better plasticity among materials with similar physical properties.

[0058] like Figure 10 As shown, rotating rigid body structures, composite structures, and chiral structures exhibit different load-bearing levels, deformation ranges, and energy absorption characteristics during compression.

[0059] To further evaluate the energy absorption capacity of different structures during compression, the cumulative energy absorption was obtained by integrating the stress-strain curve, and the specific energy absorption was calculated in combination with the specimen mass. Figure 10 (b) presents the cumulative energy absorption curves for different structures.

[0060] Formulas for calculating cumulative energy absorption and specific energy absorption: Where EA is the cumulative energy absorbed per unit volume, SEA is the specific energy absorbed, σ is the compressive stress, and ε is the specific energy absorbed per unit volume. f Let E be the failure strain, E be the total energy absorbed by the specimen before failure, and m be the specimen mass.

[0061] Depend on Figure 10 As shown in (b), the cumulative energy absorption of all three structures increases continuously with increasing strain, but the growth rate differs significantly. The RRS structure exhibits higher load-bearing capacity in the initial stage of compression, with a peak stress reaching 0.799 MPa, the highest among the three structures. However, this structure fails when the strain reaches 5.239%, resulting in a cumulative energy absorption of only 0.01420 MJ / m. 3 The peak stress of the ATC structure is only 0.265 MPa, but its failure strain reaches 10.025%, exhibiting a large deformation capacity. Therefore, its cumulative energy absorption reaches 0.01522 MJ / m. 3 It is slightly higher than the RRS structure.

[0062] In contrast, the ATC-RRS composite structure exhibits both higher load-bearing capacity and greater deformation capacity, with a peak stress reaching 0.629 MPa, significantly higher than the ATC structure; its failure strain reaches 7.993%, significantly higher than the RRS structure. Under the synergistic effect of the two structural units, the ATC-RRS structure achieved the highest cumulative energy absorption, reaching 0.02028 MJ / m² before failure. 3 This represents an improvement of 42.82% and 33.25% compared to the RRS and ATC structures, respectively.

[0063] Further analysis of the lightweight energy absorption efficiency was conducted based on the specimen mass. The masses of the RRS, ATC-RRS, and ATC structures were 52 g, 39 g, and 23 g, respectively, corresponding to specific energy absorption of 2.73 × 10⁻⁶ g and 2.73 × 10⁻⁶ g, respectively. -4 5.20×10 -4 and 6.62×10 -4 MJ·m -3 ·g -1 The results show that the ATC structure has the highest specific energy absorption, with the strongest energy absorption capacity per unit mass; the ATC-RRS structure is second; and the RRS structure is the lowest. This indicates that the reciprocal unit maintains good energy absorption capacity while reducing the structural mass, thereby improving the lightweight energy absorption efficiency of the structure. However, the reciprocal structure also suffers from insufficient early strength due to its excessively light mass.

[0064] Based on comprehensive indicators such as peak stress, failure strain, cumulative energy absorption, and specific energy absorption, it can be found that the RRS structure has the highest peak stress, but it fails earlier and its energy absorption capacity is limited; the ATC structure has a large deformation capacity and specific energy absorption, but its peak stress is low; the ATC-RRS composite structure achieves a good balance between load-bearing capacity and energy absorption capacity, exhibiting the highest cumulative energy absorption level and better comprehensive mechanical properties among the three structures.

[0065] Example 2: Parameter Analysis Simulation The shape of the structure is controlled by these four basic parameters, and two structural parameter scaling factors are set: When the size is larger, the ligament stiffness is greater. When the value is large, the rigid body outer wall stiffness is large. The larger the value of β, the larger the proportion of the ring, the smaller the tilt angle of the cell, the smaller the rotation angle of the rigid body during compression, and the larger the compression distance of the ring.

[0066] To analyze the influence of structural parameters on mechanical properties, this embodiment divides the parametric model into two groups for study. The first group is the α variation group, with α values ​​of 0.5, 0.8, 1, 1.25, and 2. While keeping the geometric parameter β constant, the parameter α is adjusted by changing the component thickness ratio t1 / t2 to analyze the influence of structural stiffness distribution on mechanical properties. The second group is the β variation group, with β values ​​of 0.3, 0.4, 0.5, 0.6, and 0.7. While keeping the parameter α essentially constant, the parameter β is adjusted by changing the geometric dimension ratio r / l1 to study the influence of structural geometry on deformation capacity and energy absorption characteristics. The parameter combinations are shown in Table 2.

[0067] Since variations in α and β result in different structural volumes, it's also necessary to consider whether the relative density of the structure is the primary factor influencing its performance. The formulas for calculating relative density and porosity are as follows: in, Where P is the relative density, V is the porosity, and P is the relative density. s V represents the solid volume of the structure, and V represents the total volume of the structure. The solid volume is obtained from the SolidWorks mass property, and the total volume of the structure is calculated from the outer envelope dimensions of the specimen.

[0068] Table 2 Geometric parameters of the parameterized model of the combined structure

[0069] While keeping the geometric configuration parameter β constant, a systematic comparative simulation analysis was conducted on the stiffness distribution parameter α. Five discrete specimens with α values ​​of 0.5, 0.8, 1.0, 1.25, and 2.0 were selected for this experiment. Increasing the ligament thickness t1 improves the flexible hinge stiffness of the four-ligament structure, while increasing the rigid body wall thickness t2 increases the supporting stiffness of the rigid skeleton.

[0070] Depend on Figure 11 and Figure 12 It is evident that during compression, since the β values ​​of several components are the same, there is no significant difference in the deformation mode of the structure under different α conditions.

[0071] Since the internal pores of the structure are basically compacted and enter the densification stage when the compressive strain reaches about 42%, the effective core data before the 42% strain are extracted for evaluation. The in-plane energy absorption characteristics and load-bearing capacity of the structure are not simply determined by the dimensionless ratio α, but significantly depend on the absolute thickness of the ligaments and rigid walls. When α=1.0, the thickness of both the ligaments and rigid walls of the specimen reaches the maximum value of this group (t1=1 mm, t2=1 mm), at which point the relative density of the structure is the highest (0.489), and the porosity is the lowest (51.14%). The thicker cell walls provide higher initial load-bearing stiffness, forming a significant initial peak stress in the early stage of compression (strain range of 0%~5%). Furthermore, during the subsequent compression and folding deformation process, the mutual contact and friction between the thicker walls are greatly enhanced, thus resulting in the largest peak stress.

[0072] When the parameter α deviates from 1.0, whether it increases or decreases, it means that the thickness of the component is weakened. For example, when α=0.5 (t1=0.5 mm, t2=1 mm) or α=2.0 (t1=1 mm, t2=0.5 mm), the porosity of the structure increases to 61.39% and 60.60%, respectively. The reduction in absolute thickness directly leads to a reduction in the effective material volume participating in plastic deformation, and at the same time weakens the energy absorption effect of contact friction between cell walls in the later stages of compression. This material reduction is reflected in the stress-strain curve as a decrease in the initial peak stress and a significant decrease in the overall stress level in the plateau region. Under similar relative density and porosity levels, the initial peak stress of the component with α=0.5 is significantly higher than that with α=2.0, while the overall energy absorption effect is significantly worse than that with α=2.0. This indicates that during the component's energy absorption process, the rigid wall dominates the initial deformation, while the annular wall and ligament dominate the overall energy absorption effect.

[0073] Although the energy absorption effect is good when α=1, the negative Poisson's ratio effect is poor in the early stage of deformation. This is also because the porosity is only 51.14%, and the inward deformation space is limited. However, when α=2, the rigid body wall is thin and the ring and ligament walls are not weakened, the anti-hand structure in the composite structure dominates the structural deformation, and the rigid body wall plays a supporting role. The structure exhibits a better negative Poisson's ratio effect.

[0074] While keeping the geometric configuration parameter β constant, a systematic comparative simulation analysis was conducted on the stiffness distribution parameter α. Five discrete specimens with α values ​​of 0.5, 0.8, 1.0, 1.25, and 2.0 were selected for this experiment. Increasing the ligament thickness t1 improves the flexible hinge stiffness of the four-ligament structure, while increasing the rigid body wall thickness t2 increases the supporting stiffness of the rigid skeleton.

[0075] From deformed cloud map ( Figure 13It can be seen that the β value affects the deformation form of the structure. As β increases, the area of ​​the inner ring of the structure increases, the volume of the structural cell increases, the tilt angle of the cell decreases, the overall rotation angle of the cell decreases, the compression stroke of the ring increases, and the rotation stroke of the rigid frame decreases.

[0076] Stress-strain curves under different β conditions are as follows Figure 14 (a) As the value increases, the node torsional angle becomes larger, resulting in better node energy absorption. The initial peak strength of β=0.3 is significantly stronger. However, because the rigid frame walls with β=0.7 come into contact and compress with each other earliest, and because the ring with β=0.7 occupies a larger volume, the ring wall and ligament wall compress with the rigid frame walls earlier. After the three are compacted together, the ring begins to absorb energy earlier and reaches peak stress earlier. In the stage of energy absorption relying on ring compression and mutual friction after compaction, the structure with smaller β mainly relies on mutual friction, while the structure with larger β mainly relies on the ring for energy absorption. According to the stress-strain curve, we can see that the structure with smaller β has a weaker energy absorption effect in the later stage than the structure with larger β. It can be said that the energy absorption effect of the ring is stronger than the energy absorption effect of mutual friction between the structural walls.

[0077] exist Figure 14 As can be seen from the (b) Poisson's ratio-strain diagram, although the energy absorption effect is better when β is larger, the negative Poisson's ratio effect is also worse. This is because the porosity is smaller when β is larger, and the inward shrinkage effect of the structure is limited.

[0078] In summary, this application proposes a chiral-rotational rigid body coupled negative Poisson's ratio composite structure, and studies its mechanical response and parameter control mechanism through experiments and numerical analysis. The results show that this structure can effectively coordinate load-bearing capacity and deformation capacity, exhibiting excellent comprehensive energy absorption performance. Experiments and simulations confirm that the advancement of this structure lies in: (1) By integrating the rigid rotation of a rigid body with the flexible bending mechanism of a chiral structure, the composite structure achieves multi-stage coordinated deformation, effectively alleviating the problems of stress concentration and deformation limitation in a single structure. Compared with a single structure, the composite structure significantly improves deformation capacity and energy absorption efficiency while maintaining a high load-bearing capacity, demonstrating superior comprehensive mechanical performance.

[0079] (2) In the α-parameter simulation, it can be found that both the increase of the wall thickness of the ring and ligament or the increase of the wall thickness of the rigid structure can enhance the energy absorption effect of the structure. The rigid body wall dominates the initial deformation, while the ring wall and ligament dominate the overall energy absorption effect. In the β-parameter simulation, it can be found that the energy absorption effect of the ring is stronger than the energy absorption effect of the friction between the structural walls. In both sets of experiments, it can be found that the negative Poisson's ratio effect in the early stage of deformation is mainly related to the porosity of the structure.

[0080] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A chiral-rotational rigid body coupled negative Poisson's ratio structure, characterized in that, It includes multiple combined unit cells, which are periodically arrayed along the planar direction and integrally connected to form an overall structure. The outer boundary of the overall structure is provided with an outer support frame (4). Each of the composite unit cells includes a rotating rigid body unit (1), a reverse-hand negative Poisson's ratio unit (2), and a flexible connecting ligament (3). The rotating rigid body unit (1) is located in the central region of the unit cell. The rotating rigid body unit (1) and the reverse-hand negative Poisson's ratio unit (2) are integrally connected to each other through the flexible connecting ligament (3) to form a composite structure. When under pressure, the negative Poisson's ratio effect is generated by coupling through a dual deformation mechanism of rigid rotation and flexible bending.

2. The chiral-rotational rigid body coupled negative Poisson's ratio structure according to claim 1, characterized in that, The rotating rigid body unit (1) includes a rigid polygonal frame (11). Multiple rigid polygonal frames (11) are centrally symmetrically distributed around the center of the unit cell and enclose a hollow area (12) located at the center of the unit cell. The corners of adjacent rigid polygonal frames (11) are connected by flexible hinges (13). When under pressure, each rigid polygonal frame (11) rotates relative to the flexible hinge (13) to provide initial load-bearing stiffness for the structure.

3. The chiral-rotational rigid body coupled negative Poisson's ratio structure according to claim 1, characterized in that, The reverse hand negative Poisson ratio unit (2) includes a circular node (21) and an inclined ligament (22); multiple circular nodes (21) are symmetrically arranged along multiple diagonal positions of the unit cell, and adjacent circular nodes (21) are integrally connected by the inclined ligament (22). When compressed, the inclined ligament (22) bends and deforms and continuously absorbs external load energy.

4. The chiral-rotational rigid body coupled negative Poisson's ratio structure according to claim 3, characterized in that, The geometry of the combined unit cell is determined by four basic geometric parameters, namely, ligament wall thickness. Hollowed-out rigid body wall thickness Radius of the central circle and ligament length Wherein, the ligament wall thickness The thickness of the inclined ligament (22) and the wall thickness of the hollow rigid body. The wall thickness of the rigid polygonal frame (11) and the radius of the central circle are given. The radius of the circular node (21) and the length of the ligament The distance from the center of the circular node (21) to the center of the unit cell; The rhomboid dimension parameters of the hollowed-out region (12) inside the unit cell satisfy the following relationship: In the formula, The half-length dimension of the rhomboid hollow area along the diagonal of the unit cell. The width of the diamond-shaped cutout area is perpendicular to the diagonal direction.

5. The chiral-rotational rigid body coupled negative Poisson's ratio structure according to claim 4, characterized in that, The tilt angle of the rigid polygonal frame (11) satisfy: The lateral side length of the combined unit cell With longitudinal side length The following relationship must be satisfied: Multiple combined unit cells are arranged in a continuous, tightly packed n*n matrix along the X and Y directions and integrally formed to create a two-dimensional periodic metamaterial structure, where n is a positive integer greater than or equal to 2; the overall length of the two-dimensional periodic metamaterial structure is... Overall width The following relationship must be satisfied: 。 6. The chiral-rotational rigid body coupled negative Poisson's ratio structure according to claim 4, characterized in that, Set the thickness ratio factor Geometric Dimension Scale ,in: The thickness ratio coefficient Used to adjust the stiffness distribution between the rotating rigid body unit (1) and the anti-handed negative Poisson's ratio unit (2); the geometric dimension scaling factor Used to regulate the tilt angle and deformation range of unit cells.

7. The chiral-rotational rigid body coupled negative Poisson's ratio structure according to claim 6, characterized in that, The relative density of the combined unit cells With porosity The following relationship must be satisfied: In the formula, For the volume of the structural entity, The volume of the outer envelope of a single cell; the relative density With thickness scaling factor and geometric dimension scaling factor It changes with the changes.

8. The chiral-rotational rigid body coupled negative Poisson's ratio structure according to claim 6, characterized in that, By adjusting the thickness ratio coefficient proportionality coefficient of the geometric dimensions To regulate the stiffness distribution, deformation mode, and energy absorption performance of the structure: Increase the thickness ratio coefficient The relative thickness of the inclined ligament (22) increases, and the overall energy absorption effect of the structure is enhanced; Increase the geometric dimension scaling factor The radius of the circular node (21) is relatively increased, and the tilt angle of the rigid polygonal frame (11) is increased. As the rotational stroke of the rigid body decreases, the compression stroke of the circular ring increases, resulting in enhanced energy absorption in the later stages of the structure, but a weakening of the negative Poisson's ratio effect.

9. The chiral-rotational rigid body coupled negative Poisson's ratio structure according to claim 5, characterized in that, The two-dimensional periodic metamaterial structure extends along the Z-axis with a set thickness. L Z This forms a three-dimensional blocky metamaterial structure.

10. The chiral-rotational rigid body coupled negative Poisson's ratio structure according to claim 1, characterized in that, During the compression loading process, the structure undergoes the following deformation stages in sequence: During the initial compression phase, the rigid polygonal frame (11) of the rotating rigid body unit (1) rotates relative to the flexible hinge (13) to provide initial load-bearing stiffness for the structure. During the continued compression phase, the inclined ligament (22) of the reverse negative Poisson's ratio unit (2) undergoes bending deformation and continues to absorb external load energy; In the further compaction stage, the hollow area (12) inside the unit cell comes into contact with and is squeezed by the inner wall of the circular node (21), which once again plays a supporting role and realizes multi-stage progressive energy dissipation.

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