Mechanical metamaterial cell with zero poisson's ratio properties

Abstract

The application discloses a mechanical metamaterial cell with zero Poisson's ratio, and belongs to the technical field of mechanical metamaterials. The cell comprises symmetrically arranged upper and lower plates, upper and lower sets of horn pegs arranged at the four corners of the inner sides of the plates, an elastic body set connected by the upper and lower sets of horn pegs, and a set of flexible hinge components arranged at the midpoint positions of the four edges of the upper and lower plates. The pre-tension of the elastic body set keeps the set of flexible hinge components pre-bent inward. When the cell bears an axial load, the set of flexible hinge components produces coordinated inward bending deformation, so that the cell shrinks along the axial direction and keeps the lateral dimension stable, realizes the axial zero Poisson's ratio characteristic, and has energy absorption capacity. The cell has self-recovery capability and high cycle life based on elastic deformation, and is modular in design, convenient to assemble, disassemble and maintain, and suitable for application scenarios such as aerospace buffer devices, biomedical implants and precision instrument supporting structures.

Description

Technical Field

[0001] This invention relates to the field of mechanical metamaterials technology, and more particularly to a mechanical metamaterial cell with zero Poisson's ratio. Background Technology

[0002] Metamaterials, as a type of artificial composite material, derive their physical properties primarily from the unique design and spatial arrangement of their structural units, rather than from the inherent properties of the material itself. By designing ordered microscopic geometric configurations, metamaterials can achieve mechanical behaviors not found in natural materials, such as zero Poisson's ratio.

[0003] Zero Poisson's ratio refers to the property that a material's dimensions perpendicular to the direction of force remain essentially unchanged under uniaxial tension or compression. Structures possessing this property can maintain cross-sectional stability during deformation, avoiding stress concentration or instability caused by lateral deformation. Therefore, they have broad application prospects in aerospace cushioning devices, biomedical implants, and precision instrument support structures. Currently, mechanical metamaterials achieving zero Poisson's ratio often employ concave hexagons, chiral meshes, or rotationally rigid elements. However, these designs often sacrifice structural load-bearing capacity and durability in pursuit of zero Poisson's ratio, resulting in overall fragility and susceptibility to plastic deformation. Furthermore, they typically lack adaptive recovery capabilities, making it difficult to return to their original shape under cyclic loading, limiting their application in applications requiring multiple uses. Some structures also suffer from complex designs, demanding fabrication processes, and insufficient reliability under multi-material or microscale conditions.

[0004] It is worth noting that existing research on zero Poisson's ratio cells mostly focuses on achieving the ideal Poisson's ratio value, while paying insufficient attention to the comprehensive mechanical properties of the structure. For example, how to maintain zero Poisson's ratio while also ensuring high load-bearing efficiency, good elastic recovery, long-term structural stability, and fatigue life. Therefore, there is an urgent need to develop a new type of mechanical metamaterial cell that can not only achieve zero Poisson's ratio characteristics but also possess comprehensive mechanical properties such as self-adaptation, self-stabilization, self-recovery, high durability, and efficient energy absorption, while also having the practical advantages of simple structure, convenient assembly and disassembly, and easy maintenance. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, this invention provides a mechanical metamaterial cell with zero Poisson's ratio properties. This cell employs a modular design, resulting in a simple structure that facilitates disassembly and maintenance. Based on the synergistic effect of the elastomer assembly and the flexible hinge component assembly, this structure possesses advantages such as self-adaptability, self-stability, self-recovery, high durability, and high energy absorption efficiency. Furthermore, under axial loads, the elastomer assembly provides deformation guidance, while the flexible hinge component assembly, through coordinated geometric bending deformation, ensures that the cell shrinks only along the axial direction, while maintaining lateral stability, thereby achieving zero Poisson's ratio characteristics in the axial direction.

[0006] It should be noted that the definitions and use of terms such as components or orientations in this invention are merely for the convenience and uniformity of description. Related terms can be replaced with equivalent terms or adjusted directionally according to the actual situation, and should not be construed as limiting this invention.

[0007] This invention proposes a mechanical metamaterial cell with zero Poisson's ratio, which mainly includes an upper top plate, a lower bottom plate, an upper claw spike assembly, a lower claw spike assembly, an elastomer assembly, and a flexible hinge component assembly. The square upper top plate and lower bottom plate are symmetrically arranged. Upper and lower claw spike assemblies are respectively located at the four corners of their opposing inner surfaces. The elastomer assembly is connected and tensioned through the upper and lower claw spike assemblies. Simultaneously, along the midpoints of the four sides of the opposing inner surfaces of the upper top plate and lower bottom plate, the flexible hinge component assembly connects them, thus forming a complete mechanical metamaterial cell with zero Poisson's ratio. The pretension applied by the elastomer assembly keeps the flexible hinge component assembly in an inward bending posture. When the cell is subjected to axial load, this pre-bending structure facilitates further coordinated inward bending deformation of the flexible hinge component assembly. Based on this deformation mechanism, the cell can contract axially while maintaining lateral dimensional stability, thereby achieving zero Poisson's ratio characteristics in the axial direction.

[0008] The flexible hinge component assembly comprises four identical flexible hinge components. Each flexible hinge component consists of two flexible hinge connecting blocks, three thick flexible hinges, and six thin flexible hinges. The two flexible hinge connecting blocks are symmetrically arranged and interconnected with the two thin flexible hinges via a thick flexible hinge. At the end of each flexible hinge connecting block furthest from the center of symmetry, there is one thick flexible hinge and two thin flexible hinges for connecting and fitting the upper top plate or lower bottom plate. Based on the elastic properties of the thick and thin flexible hinges, the flexible hinge component assembly can return to its original shape after deformation and absorb energy during the deformation process, thus giving the entire cell a self-healing function and energy absorption capability.

[0009] It should be noted that the mechanical metamaterial cell with zero Poisson's ratio property primarily exhibits recoverable elastic deformation as its deformation mechanism, and is not prone to plastic deformation within conventional load ranges, thus possessing excellent durability and a long service life. Furthermore, the modular connection method of each component allows for convenient disassembly and replacement when local components degrade or fail, greatly improving the maintainability and overall lifespan of the structure, making it suitable for applications requiring long-term or repeated use.

[0010] It should also be noted that by adjusting the elastic modulus or stiffness coefficient of the elastomer assembly, the thick flexible hinge, and the thin flexible hinge, the load-bearing capacity, shape recovery capacity, and energy absorption capacity of the cell can be proportionally adjusted within a certain range.

[0011] Technical Effects: The mechanical metamaterial cell with zero Poisson's ratio provided by this invention achieves zero Poisson's ratio characteristics in the axial direction through the synergistic design and pre-tensioning of the elastomer assembly and flexible hinge component assembly. Its deformation mechanism is primarily elastic deformation, endowing the cell with excellent self-recovery capability and high cyclic fatigue life, overcoming the shortcomings of traditional structures prone to plastic failure. Simultaneously, the modular component connection method makes the cell highly maintainable, facilitating local replacement and performance adjustment, significantly improving overall service life and practical value. This cell structure combines structural simplicity, strong energy absorption and load-bearing capacity, and self-adaptive recovery, meeting the engineering needs of high-performance, long-life metamaterial units in aerospace, biomedical, and other fields. Attached Figure Description

[0012] To clearly illustrate the embodiments and related technical solutions of the present invention, the accompanying drawings involved in the embodiments will be briefly described below. It should be understood that the following drawings are only for illustrating some embodiments of the present invention. Those skilled in the art can also obtain other related technical solutions and drawings based on these drawings without any inventive effort.

[0013] Figure 1 I is a schematic diagram of the structure of a mechanical metamaterial cell with zero Poisson's ratio provided in an embodiment of the present invention.

[0014] Figure 2 Schematic diagram II of the structure of a mechanical metamaterial cell with zero Poisson's ratio provided in an embodiment of the present invention.

[0015] Figure 3 This is a schematic diagram of the structural explosion of a mechanical metamaterial cell with zero Poisson's ratio, provided for an embodiment of the present invention.

[0016] Figure 4 An exploded view of a flexible hinge connection component structure with zero Poisson's ratio mechanical metamaterial cell provided in an embodiment of the present invention.

[0017] Figure 5 This is a schematic diagram of the axial compression deformation of a mechanical metamaterial cell with zero Poisson's ratio, provided as an embodiment of the present invention.

[0018] Labeling Explanation: 1. Top Plate; 2. Bottom Plate; 3. Upper Claw Pin Assembly; 301. First Upper Claw Pin; 302. Second Upper Claw Pin; 303. Third Upper Claw Pin; 304. Fourth Upper Claw Pin; 4. Lower Claw Pin Assembly; 401. First Lower Claw Pin; 402. Second Lower Claw Pin; 403. Third Lower Claw Pin; 404. Fourth Lower Claw Pin; 5. Elastomer Assembly; 501. First Elastomer; 502. Second Elastomer; 503. Third Elastomer; 504. Fourth Elastomer; 6. Flexible Hinge Component Assembly; 601. First Flexible Hinge Component; 602. Second Flexible Hinge Component; 603. Third Flexible Hinge Component; 604. Fourth Flexible Hinge Component; 6001. Flexible Hinge Connector Block; 6002. Thick Flexible Hinge; 6003. Thin Flexible Hinge. Detailed Implementation

[0019] To clearly illustrate the embodiments of the present invention, a detailed description will be provided below in conjunction with the accompanying drawings. The same or similar reference numerals in the drawings represent the same or similar components or components having the same or similar functions. It should be understood that the following description in conjunction with the accompanying drawings is merely exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0020] It should be noted that the same reference numerals or numbers may be used repeatedly in different embodiments or figures. This repetition is only for simplifying the text description and figure indication, and does not in itself indicate that there is necessarily a specific relationship between the various embodiments or structures.

[0021] In the description of this invention, the terms "upper," "lower," "inner side," "symmetric," "center," "four corners," "axial," and "lateral" are defined based on the orientations or positions shown in the accompanying drawings. These definitions are merely for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the components referred to must have a specific orientation, nor should they constitute a limitation on the invention. Furthermore, the terms "first," "second," "third," and "fourth," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance, nor should they be construed as limiting the number of technical features described. Based on this description, a feature specified as "X" may explicitly or implicitly include one or more of that feature.

[0022] The following description illustrates different structures of the present invention through specific embodiments and accompanying drawings, with particular examples focusing on the components and their arrangement. It should be understood that these examples are merely illustrative and should not be construed as limiting the invention.

[0023] Please see Figures 1 to 3This invention provides a mechanical metamaterial cell with zero Poisson's ratio, which mainly includes an upper top plate 1, a lower bottom plate 2, an upper spike group 3, a lower spike group 4, an elastomer group 5, and a flexible hinge component group 6. The upper top plate 1 and the lower bottom plate 2 are both square and symmetrically arranged. On the inner surfaces of the upper top plate 1 and the lower bottom plate 2, upper spike groups 3 and lower spike groups 4 are respectively arranged at the four corners. The elastic body assembly 5 is connected and axially tensioned through the upper claw nail assembly 3 and the lower claw nail assembly 4. Specifically: the two ends of the first elastic body 501 are respectively connected to the corresponding holes of the upper top plate 1 and the lower bottom plate 2 through the first upper claw nail 301 and the first lower claw nail 401; the two ends of the second elastic body 502 are respectively connected to the corresponding holes of the upper top plate 1 and the lower bottom plate 2 through the second upper claw nail 302 and the second lower claw nail 402; the two ends of the third elastic body 503 are respectively connected to the corresponding holes of the upper top plate 1 and the lower bottom plate 2 through the third upper claw nail 303 and the third lower claw nail 403; and the two ends of the fourth elastic body 504 are respectively connected to the corresponding holes of the upper top plate 1 and the lower bottom plate 2 through the fourth upper claw nail 304 and the fourth lower claw nail 404. Meanwhile, on the inner surfaces of the upper top plate 1 and the lower bottom plate 2, which are opposite each other, a flexible hinge component group 6 is used to connect them along the midpoint of the four side lines, thereby forming a complete mechanical metamaterial cell with zero Poisson's ratio.

[0024] See Figures 1 to 4 The flexible hinge component group 6 includes a first flexible hinge component 601, a second flexible hinge component 602, a third flexible hinge component 603, and a fourth flexible hinge component 604. The first flexible hinge component 601, the second flexible hinge component 602, the third flexible hinge component 603, and the fourth flexible hinge component 604 have the same structure, each consisting of two flexible hinge connecting blocks 6001, three thick flexible hinges 6002, and six thin flexible hinges 6003. Specifically, the two flexible hinge connecting blocks 6001 are arranged symmetrically and are interconnected with the two thin flexible hinges 6003 through one thick flexible hinge 6002. At the end of each flexible hinge connecting block 6001 furthest from the center of symmetry, one thick flexible hinge 6002 and two thin flexible hinges 6003 are respectively provided for connection and engagement with the upper top plate 1 or the lower bottom plate 2. Furthermore, based on the elastic properties of the thick flexible hinge 6002 and the thin flexible hinge 6003, the flexible hinge component group 6 can recover its initial shape after being deformed by force and absorb energy during the deformation process, thereby enabling the entire cell to have good shape self-recovery function and energy absorption capacity.

[0025] See Figures 1 to 5The pretension provided by the elastomer assembly 5 maintains the inward pre-bending posture of the flexible hinge component assembly 6. When the cell is subjected to an axial load (i.e., along direction A), this pre-bending structure causes the flexible hinge component assembly 6 to undergo further coordinated inward bending deformation. Based on this deformation mechanism, when the cell contracts axially, it can maintain lateral dimensional stability, thereby achieving zero Poisson's ratio characteristics in the axial direction. At the same time, the deformation of the cell is mainly recoverable elastic deformation, and it is not prone to plastic deformation under normal working loads, thus exhibiting good durability and a long service life. In addition, based on the modular connection design between the components, it can be easily disassembled and replaced when the performance of local components degrades or fails, significantly improving the maintainability and overall service life of the structure, making it suitable for engineering scenarios requiring long-term or repeated use.

[0026] It should be noted that by adjusting the elastic modulus or stiffness coefficient of the elastomer group 5, the thick flexible hinge 6002 and the thin flexible hinge 6003, the load-bearing capacity, shape recovery capacity and energy absorption capacity of the cell can be adjusted to a certain extent in a proportional manner.

[0027] In summary, although the present invention has been described in detail above with reference to specific embodiments, the scope of protection of the present invention is not limited to the specific embodiments described. Those skilled in the art can modify, alter, or adapt these embodiments without departing from the principles of the present invention. All such changes or substitutions based on the inventive concept should be covered within the scope of protection of the present invention.

Claims

1. A mechanical metamaterial unit cell with zero Poisson's ratio properties, characterized in that, The application relates to a kind of cellular structures, comprising: Upper top plate (1) and lower bottom plate (2), both are square and relative symmetric arrangement;Upper horn group (3) and lower horn group (4) are respectively arranged in the four corner positions of the opposite inner side of the upper top plate (1) and lower bottom plate (2);Elastic body group (5) is connected by the upper horn group (3) and lower horn group (4) and applies axial pre-tension;Flexible hinge component group (6) is arranged in the midpoint position of the four edge lines of the opposite inner side of the upper top plate (1) and lower bottom plate (2), for connecting two and constituting complete cell structure;Wherein, the pre-tension provided by the elastic body group (5) makes the flexible hinge component group (6) keep the pre-bending posture inward;When cell bears axial load, the flexible hinge component group (6) occurs coordinated inward bending deformation, makes cell contract along axial direction and keep stable in lateral dimension, so as to realize axial zero poisson's ratio characteristic;The upper horn group (3) includes first upper horn (301), second upper horn (302), third upper horn (303) and fourth upper horn (304);The lower horn group (4) includes first lower horn (401), second lower horn (402), third lower horn (403) and fourth lower horn (404);The elastic body group (5) includes first elastic body (501), second elastic body (502), third elastic body (503) and fourth elastic body (504), and the both ends of each elastic body are connected by corresponding upper horn and lower horn in axial tension;The flexible hinge component group (6) includes first flexible hinge component (601), second flexible hinge component (602), third flexible hinge component (603) and fourth flexible hinge component (604);The first flexible hinge component (601), second flexible hinge component (602), third flexible hinge component (603) and fourth flexible hinge component (604) all include two symmetrically arranged flexible hinge connecting blocks (6001), three thick flexible hinges (6002) and six thin flexible hinges (6003);Two flexible hinge connecting blocks (6001) are connected by a thick flexible hinge (6002) and two thin flexible hinges (6003), and one thick flexible hinge (6002) and two thin flexible hinges (6003) are arranged at the end of each flexible hinge connecting block (6001) away from the symmetry center, for connecting the upper top plate (1) or lower bottom plate (2).

2. The mechanical metamaterial unit cell with zero Poisson's ratio properties of claim 1, wherein: The thick flexible hinge (6002) and thin flexible hinge (6003) have elasticity, so that the flexible hinge component group (6) can recover the initial shape after deformation, and absorb energy during deformation, so that the cell has self-recovery function and energy absorption capacity.

3. The mechanical metamaterial unit cell with zero Poisson's ratio properties of claim 1, wherein: By adjusting the elastic modulus or stiffness coefficient of the elastic body group (5), thick flexible hinge (6002) and thin flexible hinge (6003), the load capacity, shape recovery capacity and energy absorption capacity of the cell can be adjusted correspondingly.

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