Mechanical metamaterial unit cells and structures

Abstract

The application discloses a kind of mechanical metamaterial units and structures.The mechanical metamaterial unit includes: base, first support, second support and top cover, the first support and the second support are spaced apart in the length direction of the base, the first support includes first intermediate straight section and respectively from the two ends of the first intermediate straight section to the side away from the second support First arc section and second arc section, the second support includes second intermediate straight section and respectively from the second intermediate straight section to the side away from the first support Third arc section and fourth arc section, the first arc section and the third arc section are connected with the base, and the second arc section and the fourth arc section are connected with the top cover.The mechanical metamaterial unit of the application not only has simple and compact structure, light weight, strong carrying capacity, reusable, but also has excellent low-frequency vibration isolation performance and buffering performance.

Description

Technical Field

[0001] This invention belongs to the field of mechanical metamaterials technology, specifically relating to a mechanical metamaterial unit and structure. Background Technology

[0002] Vibration refers to the periodic reciprocating motion of an object when subjected to external forces, typically lasting for a period of time, while impact is generally a one-time event that carries a large amount of energy at the moment of impact. For example, when a car is driven on an uneven road, continuous mechanical vibration can cause passenger discomfort and wear and tear on car parts. Furthermore, collisions with obstacles on the road can cause impacts, leading to vehicle damage and personal injury. Therefore, in the field of engineering safety, it is crucial to isolate adverse vibrations and mitigate harmful impacts to protect precision equipment and personal safety.

[0003] Mechanical metamaterials are materials with novel artificial structures that exhibit mechanical properties not found in natural materials. As an important branch of mechanical metamaterials, vibration isolation mechanical metamaterials directly block the transmission of vibrations using their quasi-zero stiffness, exhibiting superior low-frequency vibration isolation effects compared to traditional vibration isolation methods. Buffer mechanical metamaterials, on the other hand, dissipate the energy from impacts through structural deformation, thereby weakening the impact intensity. Compared to conventional buffer materials, they offer advantages such as reusability, self-recovery, and adjustable performance.

[0004] Current research largely focuses on designing metamaterials with single functions, with limited research on metamaterials that simultaneously possess vibration isolation and buffering capabilities. Furthermore, existing metamaterials suffer from complex structures and poor protective performance. Therefore, there is an urgent need to design a multifunctional mechanical metamaterial that combines vibration isolation and buffering to address these issues. Summary of the Invention

[0005] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, one object of this invention is to propose a mechanical metamaterial unit and structure. This mechanical metamaterial unit has a simple and compact structure, while also possessing excellent low-frequency vibration isolation and buffering performance.

[0006] In a first aspect, the present invention provides a mechanical metamaterial unit. According to an embodiment of the present invention, the mechanical metamaterial unit comprises:

[0007] Base;

[0008] A first support member and a second support member are spaced apart along the length of the base. The first support member includes a first straight section in the middle and a first arc segment and a second arc segment extending from both ends of the first straight section away from the second support member. The second support member includes a second straight section in the middle and a third arc segment and a fourth arc segment extending from the second straight section away from the first support member. The first arc segment and the third arc segment are both connected to the base.

[0009] The top cover, the second arc segment, and the fourth arc segment are all connected to the top cover.

[0010] The stiffness of the first support member is less than that of the second support member.

[0011] According to the above embodiments of the mechanical metamaterial unit of the present invention, by arranging a first support member and a second support member at intervals along the length direction of the base, and with the first arc segment of the first support member and the third arc segment of the second support member respectively connected to the base, and the second arc segment of the first support member and the fourth arc segment of the second support member respectively connected to the top cover, the mechanical metamaterial unit has a simple and compact structure and is lightweight. When compressed along a direction perpendicular to the base or top cover, under the guiding action of the first, second, third, and fourth arc segments, the first and second support members change from an initial state to an opposing buckling deformation state, and then enter a state of mutual contact. This process generates a quasi-zero stiffness mechanical response. Therefore, the mechanical metamaterial unit has excellent low-frequency vibration isolation performance. Simultaneously, the strength of the mechanical metamaterial unit increases when the first and second support members are in mutual contact, thus possessing a strong load-bearing capacity. Subsequently, due to the stiffness of the first support member... With a stiffness less than that of the second support member, the first support member undergoes buckling mode changes under the compression of the second support member. Finally, the first support member suddenly buckles, converting its strain energy into kinetic energy and releasing it, achieving a significant energy dissipation effect. Therefore, this mechanical metamaterial unit possesses excellent buffering performance. After the first support member buckles, both the first and second supports form a state of unidirectional buckling. During unloading, both the first and second supports maintain this unidirectional buckling state until they fully return to their initial state. Thus, this mechanical metamaterial unit is reusable. Therefore, the mechanical metamaterial unit of this invention not only has a simple and compact structure, is lightweight, has high load-bearing capacity, and is reusable, but also possesses excellent low-frequency vibration isolation and buffering performance.

[0012] In addition, the mechanical metamaterial unit according to the above embodiments of the present invention may also have the following additional technical features:

[0013] In some embodiments of the present invention, the first intermediate straight segment has the same thickness as the first and second arc segments, the second intermediate straight segment has the same thickness as the third and fourth arc segments, and the thickness of the first intermediate straight segment is less than the thickness of the second intermediate straight segment. This facilitates a significant energy dissipation effect.

[0014] In some embodiments of the present invention, the height of the first support member is the same as the height of the second support member. This is beneficial to improving the reusability of the mechanical metamaterial unit.

[0015] In some embodiments of the present invention, the first arc segment, the second arc segment, the third arc segment, and the fourth arc segment all have the same radius. This is beneficial for improving the low-frequency vibration isolation performance of the mechanical metamaterial unit.

[0016] In a second aspect, the present invention proposes a mechanical metamaterial structure. According to an embodiment of the invention, the mechanical metamaterial structure includes a first connector and a second connector, with a plurality of the aforementioned mechanical metamaterial units disposed between the first connector and the second connector. The first connector is connected to the base of the plurality of mechanical metamaterial units, and the second connector is connected to the top cover of the plurality of mechanical metamaterial units. Therefore, the mechanical metamaterial structure has strong load-bearing capacity, is reusable, and also possesses excellent low-frequency vibration isolation and buffering performance.

[0017] In addition, the mechanical metamaterial structure according to the above embodiments of the present invention may also have the following additional technical features:

[0018] In some embodiments of the present invention, the first connector includes a first connecting plate and a second connecting plate arranged in a cross configuration, with the middle portion of the first connecting plate connected to the middle portion of the second connecting plate. The second connector includes a third connecting plate and a fourth connecting plate arranged in a cross configuration, with the middle portions of the third connecting plate connected to the middle portions of the fourth connecting plate. The extending direction of the first connecting plate is parallel to the extending direction of the third connecting plate. A plurality of mechanical metamaterial units are disposed between the first connecting plate and the third connecting plate. The extending direction of the second connecting plate is parallel to the extending direction of the fourth connecting plate. This arrangement improves the load-bearing capacity and reusability of the mechanical metamaterial structure.

[0019] In some embodiments of the present invention, the first connecting plate has a first groove with an opening facing the second connecting plate in its middle portion, and the second connecting plate has a second groove with an opening facing the first connecting plate in its middle portion. The first groove engages with the bottom of the second groove, and the second groove engages with the bottom of the first groove. The third connecting plate has a third groove with an opening facing the fourth connecting plate in its middle portion, and the fourth connecting plate has a fourth groove with an opening facing the third connecting plate in its middle portion. The third groove engages with the bottom of the fourth groove, and the fourth groove engages with the bottom of the third groove.

[0020] In some embodiments of the present invention, a plurality of the mechanical metamaterial units are symmetrically arranged about the centerline of the first connector. This is beneficial for improving the load-bearing capacity and reusability of the mechanical metamaterial structure.

[0021] In some embodiments of the present invention, the above-described mechanical metamaterial structure further includes a limiting post disposed between the first connector and the second connector, the limiting post being connected to either the first connector or the second connector, and the heights of both the first support member and the second support member being greater than the height of the limiting post. This improves the reusability of the mechanical metamaterial structure.

[0022] In some embodiments of the present invention, multiple mechanical metamaterial units are arranged at intervals in the circumferential direction of the limiting post. This is beneficial for improving the load-bearing capacity and reusability of the mechanical metamaterial structure.

[0023] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0024] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0025] Figure 1 This is a schematic diagram of the structure of a mechanical metamaterial unit according to an embodiment of the present invention;

[0026] Figure 2 This is a deformation diagram of a mechanical metamaterial unit according to an embodiment of the present invention;

[0027] Figure 3 This is one of the schematic diagrams of a mechanical metamaterial structure according to an embodiment of the present invention;

[0028] Figure 4 This is a second schematic diagram of a mechanical metamaterial structure according to an embodiment of the present invention;

[0029] Figure 5This is the third schematic diagram of a mechanical metamaterial structure according to an embodiment of the present invention;

[0030] Figure 6 This is a force-displacement curve of the mechanical metamaterial unit in Example 1;

[0031] Figure 7 These are test diagrams of the vibration isolation performance of the mechanical metamaterial structure in Example 2;

[0032] Figure 8 These are test diagrams of the buffering performance of the mechanical metamaterial structures in Example 2 and Comparative Example 1.

[0033] Figure label:

[0034] 100-Mechanical metamaterial structure; 10-Mechanical metamaterial unit; 11-Base; 12-First support member; 121-First middle straight section; 122-First arc section; 123-Second arc section; 13-Second support member; 131-Second middle straight section; 132-Third arc section; 133-Fourth arc section; 14-Top cover; 20-First connector; 21-First connecting plate; 211-First groove; 22-Second connecting plate; 221-Second groove; 30-Second connector; 31-Third connecting plate; 311-Third groove; 32-Fourth connecting plate; 321-Fourth groove; 40-Limiting post. Detailed Implementation

[0035] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0036] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0037] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0038] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0039] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0040] In a first aspect, the present invention proposes a mechanical metamaterial unit. According to an embodiment of the invention, reference is made to... Figure 1 The mechanical metamaterial unit 10 includes a base 11, a first support member 12, a second support member 13, and a top cover 14. The first support member 12 and the second support member 13 are spaced apart along the length of the base 11. The first support member 12 includes a first intermediate straight section 121 and a first arc segment 122 and a second arc segment 123 extending from both ends of the first intermediate straight section 121 toward the side away from the second support member 13, respectively. The second support member 13 includes a second intermediate straight section 131 and a third arc segment 132 and a fourth arc segment 133 extending from the second intermediate straight section 131 toward the side away from the first support member 12, respectively. The first arc segment 122 and the third arc segment 132 are both connected to the base 11, and the second arc segment 123 and the fourth arc segment 133 are both connected to the top cover 14. The stiffness of the first support member 12 is less than the stiffness of the second support member 13.

[0041] According to the above-described embodiment of the present invention, the mechanical metamaterial unit 10, by arranging a first support member 12 and a second support member 13 at intervals along the length direction of the base 11, and by connecting the first arc segment 122 of the first support member 12 and the third arc segment 132 of the second support member 13 to the base 11, and by connecting the second arc segment 123 of the first support member 12 and the fourth arc segment 133 of the second support member 13 to the top cover 14, makes the mechanical metamaterial unit 10 simple and compact in structure and lightweight. (Reference) Figure 2 When compressed along a direction perpendicular to the base 11 or top cover 14, under the guidance of the first arc segment 122, the second arc segment 123, the third arc segment 132, and the fourth arc segment 133, the first support member 12 and the second support member 13 change from the initial state a1 to a buckling deformation state in opposite directions, and then enter a state of mutual contact b1. This process generates a mechanical response with quasi-zero stiffness. As a result, the mechanical metamaterial unit has excellent low-frequency vibration isolation performance. At the same time, when the first support member 12 and the second support member 13 are in mutual contact, the strength of the mechanical metamaterial unit 10 increases, thus having a strong load-bearing capacity. Subsequently, because the stiffness of the first support member 12 is less than that of the second support member 13, the mechanical metamaterial unit 10 has a strong load-bearing capacity. The stiffness of the support member 13 is such that the first support member 12 undergoes a buckling mode change under the compression of the second support member 13, forming state c1. Finally, the first support member 12 undergoes a sudden jump (i.e., a sudden elastic change), converting its strain energy into kinetic energy and releasing it, which can achieve a significant energy dissipation effect. Therefore, the mechanical metamaterial unit 10 has excellent buffering performance. After the first support member 12 undergoes a sudden jump, the first support member 12 and the second support member 13 form a state d1 of unidirectional buckling. During unloading, the first support member 12 and the second support member 13 maintain a state e1 of unidirectional buckling until they completely return to the initial state a1. Therefore, the mechanical metamaterial unit 10 has the characteristic of being reusable. Thus, the mechanical metamaterial unit 10 of the present invention is not only simple and compact in structure, lightweight, and has a strong load-bearing capacity, and is reusable, but also has excellent low-frequency vibration isolation performance and buffering performance.

[0042] According to an embodiment of the present invention, the first intermediate straight section 121 has the same thickness as the first arc section 122 and the second arc section 123, and the second intermediate straight section 131 has the same thickness as the third arc section 132 and the fourth arc section 133. The thickness of the first intermediate straight section 121 is less than the thickness of the second intermediate straight section 131. This facilitates manufacturing and allows the stiffness of the first support member 12 to be less than that of the second support member 13. During compression along a direction perpendicular to the base 11 or the top cover 14, after the first support member 12 and the second support member 13 enter a state of mutual contact, the first support member 12 can undergo buckling mode changes under the compression of the second support member 13 and experience a sudden jump, converting its strain energy into kinetic energy release, thereby achieving a significant energy dissipation effect.

[0043] According to an embodiment of the present invention, the height of the first support member 12 is the same as the height of the second support member 13. This facilitates the dispersion of impact forces on the mechanical metamaterial unit 10, thereby improving the reusability of the mechanical metamaterial unit 10. According to a specific embodiment of the present invention, the radii of the first arc segment 122, the second arc segment 123, the third arc segment 132, and the fourth arc segment 133 are all the same. This facilitates manufacturing and further facilitates guiding the first support member 12 and the second support member 13 to buckle towards each other and come into contact, generating a quasi-zero stiffness mechanical response, thereby improving the low-frequency vibration isolation performance of the mechanical metamaterial unit 10.

[0044] It should be noted that the materials and geometric parameters of the base 11, the first support 12, the second support 13, and the top cover 14 are not particularly limited. Those skilled in the art can choose according to actual needs, as long as the purpose of avoiding plastic deformation of the mechanical metamaterial unit 10 can be achieved. For example, the base 11, the first support 12, the second support 13, and the top cover 14 can be made of plastic (such as polylactic acid) or metal (such as aluminum alloy).

[0045] Furthermore, the quasi-zero stiffness characteristics and energy consumption of the aforementioned mechanical metamaterial unit are adjustable. For example, the quasi-zero stiffness characteristics and energy consumption of the mechanical metamaterial unit can be finely adjusted by adjusting the thickness of the first support member, the thickness of the second support member, and the distance between the first intermediate straight section and the second intermediate straight section.

[0046] In a second aspect, the present invention proposes a mechanical metamaterial structure. According to an embodiment of the invention, reference is made to... Figure 3 The mechanical metamaterial structure 100 includes a first connector 20 and a second connector 30. Multiple mechanical metamaterial units 10 are disposed between the first connector 20 and the second connector 30. The first connector 20 is connected to the base 11 of the multiple mechanical metamaterial units 10, and the second connector 30 is connected to the top cover 14 of the multiple mechanical metamaterial units 10. Therefore, the first connector 20 and the second connector 30 can serve as a frame for mounting the multiple mechanical metamaterial units 10, providing a fixing function for the multiple mechanical metamaterial units 10. This gives the mechanical metamaterial structure 100 the characteristics of high load-bearing capacity, reusability, and excellent low-frequency vibration isolation and buffering performance. It should be noted that the features and advantages described above for the mechanical metamaterial units also apply to the mechanical metamaterial structure, and will not be repeated here.

[0047] According to an embodiment of the present invention, reference Figure 3Multiple mechanical metamaterial units 10 are symmetrically arranged about the centerline of the first connector 20. This helps to disperse the impact force on the mechanical metamaterial structure 100, making it easier to return to its initial state, thereby improving the load-bearing capacity and reusability of the mechanical metamaterial structure 100.

[0048] According to an embodiment of the present invention, reference Figure 3 The mechanical metamaterial structure 100 also includes a limiting post 40 disposed between the first connector 20 and the second connector 30. The limiting post 40 is connected to the first connector 20, and the heights of both the first support 12 and the second support 13 are greater than the height of the limiting post 40. This helps to limit the deformation of the first support 12 after a sudden jump, making it easier for the mechanical metamaterial unit 10 to return to its initial state, thereby improving the reusability of the mechanical metamaterial structure 100. It should be noted that the limiting post 40 can also be connected to the second connector 30.

[0049] According to a specific embodiment of the present invention, a plurality of mechanical metamaterial units 10 are arranged at intervals in the circumferential direction of the limiting post 40. This further facilitates the dispersion of impact forces on the mechanical metamaterial structure 100, making it easier to return to its initial state, thereby improving the load-bearing capacity and reusability of the mechanical metamaterial structure 100.

[0050] It should be noted that the materials of the first connector 20, the second connector 30, and the limiting post 40 are not particularly limited. Those skilled in the art can choose according to actual needs. For example, they can be made of plastic (such as polylactic acid) or metal (such as aluminum alloy).

[0051] According to an embodiment of the present invention, reference Figure 3 The first connector 20 may include a first connecting plate 21 and a second connecting plate 22 arranged in a cross configuration, with the middle portion of the first connecting plate 21 connected to the middle portion of the second connecting plate 22. The second connector 30 may include a third connecting plate 31 and a fourth connecting plate 32 arranged in a cross configuration, with the middle portion of the third connecting plate 31 connected to the middle portion of the fourth connecting plate 32. The extension direction of the first connecting plate 21 is parallel to the extension direction of the third connecting plate 31. Multiple mechanical metamaterial units 10 are provided between the first connecting plate 21 and the third connecting plate 31. The extension direction of the second connecting plate 22 is parallel to the extension direction of the fourth connecting plate 32. Multiple mechanical metamaterial units 10 are provided between the second connecting plate 22 and the fourth connecting plate 32. This is beneficial for improving the stability of the mechanical metamaterial structure 100, thereby improving the load-bearing capacity and reusability of the mechanical metamaterial structure 100.

[0052] According to an embodiment of the present invention, reference Figure 4 and Figure 5The first connecting plate 21 has a first groove 211 with an opening facing the second connecting plate 22 in its middle portion, and the second connecting plate 22 has a second groove 221 with an opening facing the first connecting plate 21 in its middle portion. The first groove 211 engages with the bottom of the second groove 221, and the second groove 221 engages with the bottom of the first groove 211. The third connecting plate 31 has a third groove 311 with an opening facing the fourth connecting plate 32 in its middle portion, and the fourth connecting plate 32 has a fourth groove 321 with an opening facing the third connecting plate 31 in its middle portion. The third groove 311 engages with the bottom of the fourth groove 321, and the fourth groove 321 engages with the bottom of the third groove 311. This further improves the stability of the mechanical metamaterial structure 100, thereby enhancing its load-bearing capacity and reusability.

[0053] The present invention will now be described with reference to specific embodiments. It should be noted that these embodiments are merely descriptive and do not limit the present invention in any way.

[0054] Example 1

[0055] refer to Figure 1 The mechanical metamaterial unit 10 includes a base 11, a first support member 12, a second support member 13, and a top cover 14. The first support member 12 and the second support member 13 are spaced apart along the length of the base 11. The first support member 12 includes a first intermediate straight section 121 and a first arc segment 122 and a second arc segment 123 extending from both ends of the first intermediate straight section 121 toward the side away from the second support member 13, respectively. The second support member 13 includes a second intermediate straight section 131 and a third arc segment 132 and a fourth arc segment 133 extending from the second intermediate straight section 131 toward the side away from the first support member 12, respectively. The first arc segment 122 and the third arc segment 132 are both connected to the base 11, and the second arc segment 123 and the fourth arc segment 133 are both connected to the top cover 14. The stiffness of the first support member 12 is less than the stiffness of the second support member 13. The thickness t1 of the first intermediate straight segment 121, the first arc segment 122, and the second arc segment 123 is 0.6 mm, and the thickness t2 of the second intermediate straight segment 131, the third arc segment 132, and the fourth arc segment 133 is 1 mm. The height L of the first support member 12 and the second support member 13 is 80 mm. The radius R of the first arc segment 122, the second arc segment 123, the third arc segment 132, and the fourth arc segment 133 is 3 mm, the distance S between the first intermediate straight segment 121 and the second intermediate straight segment 131 is 12 mm, and the out-of-plane thickness b (the dimension along the direction perpendicular to the plane containing the first support member 12 and the second support member 13) of the mechanical metamaterial unit 10 is 15 mm. This mechanical metamaterial unit 10 is integrally formed by 3D printing of polylactic acid.

[0056] The deformation process of the aforementioned mechanical metamaterial unit 10 under axial compression is as follows: Figure 2 As shown, the corresponding force-displacement curves are as follows: Figure 6 As shown, under axial compression, the first support member 12 and the second support member 13 transform from the initial state a1 to an opposing buckling deformation state, and then enter a state b1 of mutual contact. This process generates a quasi-zero stiffness mechanical response. Therefore, this mechanical metamaterial unit exhibits excellent low-frequency vibration isolation performance. Simultaneously, with the first support member 12 and the second support member 13 in mutual contact, the strength of the mechanical metamaterial unit 10 increases, thus possessing a strong load-bearing capacity. Subsequently, because the stiffness of the first support member 12 is less than that of the second support member 13, the first support member 12, under the compression of the second support member 13... The buckling mode changes, forming state c1. Finally, the first support 12 undergoes a sudden jump (i.e., a sudden elastic change), converting its strain energy into kinetic energy and releasing it, which can achieve a significant energy dissipation effect. Thus, the mechanical metamaterial unit 10 has excellent buffering performance. After the first support 12 undergoes a sudden jump, the first support 12 and the second support 13 form a buckling state d1 in the same direction. During unloading, the first support 12 and the second support 13 remain in a buckling state e1 in the same direction until they are completely restored to the initial state a1. Thus, the mechanical metamaterial unit 10 has the characteristic of being reusable.

[0057] Example 2

[0058] refer to Figures 3-5The mechanical metamaterial structure 100 includes a first connector 20 and a second connector 30. Four mechanical metamaterial units 10 as described in Embodiment 1 are disposed between the first connector 20 and the second connector 30. The first connector 20 is connected to the base 11 of the four mechanical metamaterial units 10, and the second connector 30 is connected to the top cover 14 of the four mechanical metamaterial units 10. The mechanical metamaterial structure 100 also includes a limiting post 40 disposed between the first connector 20 and the second connector 30. The limiting post 40 is connected to the first connector 20, and the heights of the first support member 12 and the second support member 13 are both greater than the height of the limiting post 40. The four mechanical metamaterial units 10 are arranged at intervals around the circumference of the limiting post 40. The first connector 20 includes a first connecting plate 21 and a second connecting plate 22 arranged in a cross configuration. The first connecting plate 21 has a first groove 211 with an opening facing the second connecting plate 22 in its middle portion. The second connecting plate 22 has a second groove 221 with an opening facing the first connecting plate 21 in its middle portion. The first groove 211 engages with the bottom of the second groove 221, and the second groove 221 engages with the bottom of the first groove 211. The second connector 30 includes a third connecting plate 31 and a fourth connecting plate 32 arranged in a cross configuration. The third connecting plate 31 has a third groove 311 with an opening facing the fourth connecting plate 32 in its middle portion. The fourth connecting plate 32 has a fourth groove 321 with an opening facing the third connecting plate 31 in its middle portion. The third groove 311 engages with the bottom of the fourth groove 321, and the fourth groove 321 engages with the bottom of the third groove 311. The extension direction of the first connecting plate 21 is parallel to the extension direction of the third connecting plate 31. Two mechanical metamaterial units 10 as described in Embodiment 1 are provided between the first connecting plate 21 and the third connecting plate 31. The extension direction of the second connecting plate 22 is parallel to the extension direction of the fourth connecting plate 32. Two mechanical metamaterial units 10 as described in Embodiment 1 are provided between the second connecting plate 22 and the fourth connecting plate 32.

[0059] Low-frequency vibration isolation tests were conducted on the above-mentioned mechanical metamaterial structure: a preload of 9.5 kg was applied in the axial direction, and a vibrator was used to vibrate the bottom (active side) of the first connector. The vibration transmission at the top (passive side) of the second connector was tested, and the vibration transmission rate (i.e., the ratio of the vibration magnitude on the active side to the vibration magnitude on the passive side) in the mechanical metamaterial structure was calculated.

[0060] Impact tests were conducted on the aforementioned mechanical metamaterial structure: a 2.4 kg cuboid impact block was used and dropped freely from different impact heights to test the impact acceleration of the impact block after impacting the sample.

[0061] Comparative Example 1

[0062] The difference from Embodiment 2 is that the first support member includes a first middle straight section and a first arc segment and a second arc segment extending from both ends of the first middle straight section toward the side closer to the second support member, respectively. The second support member includes a second middle straight section and a third arc segment and a fourth arc segment extending from the second middle straight section toward the side closer to the first support member, respectively. The first arc segment and the third arc segment are both connected to the base, and the second arc segment and the fourth arc segment are both connected to the top cover. The rest is the same as in Embodiment 2.

[0063] The low-frequency vibration isolation test results of the mechanical metamaterial structure in Example 2 are as follows: Figure 7 As shown, the horizontal axis represents different vibration frequencies, and the vertical axis represents the vibration transmissibility in the mechanical metamaterial structure. When the transmissibility is less than 0, the metamaterial has the effect of isolating vibrations. Figure 7 It can be seen that the mechanical metamaterial structure can effectively isolate vibrations above 13Hz under a preload of 9.5kg, achieving low-frequency vibration isolation under high static load.

[0064] The impact test results of the mechanical metamaterial structures in Example 2 and Comparative Example 1 are as follows: Figure 8 As shown, the horizontal axis represents the different falling heights of the impact block, representing the magnitude of the impact energy, while the vertical axis represents the impact acceleration, reflecting the degree to which the metamaterial absorbs the impact energy. The smaller the impact acceleration, the better the buffering effect of the metamaterial. Figure 8 It can be seen that, compared with Comparative Example 1, the mechanical metamaterial structure of Example 2 has a significant buffering effect.

[0065] As can be seen from Examples 1-2, the mechanical metamaterial unit structure of the present invention is simple and compact, has strong load-bearing capacity, is reusable, and has excellent low-frequency vibration isolation and buffering performance. The mechanical metamaterial structure of the present invention not only ensures static load-bearing capacity, but also realizes low-frequency vibration isolation and buffering functions under dynamic action.

[0066] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0067] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A mechanical metamaterial unit, characterized in that, include: Base; A first support member and a second support member are spaced apart along the length of the base. The first support member includes a first straight section in the middle and a first arc segment and a second arc segment extending from both ends of the first straight section away from the second support member. The second support member includes a second straight section in the middle and a third arc segment and a fourth arc segment extending from both ends of the second straight section away from the first support member. The first arc segment and the third arc segment are both connected to the base. The top cover, the second arc segment, and the fourth arc segment are all connected to the top cover. The stiffness of the first support member is less than that of the second support member.

2. The mechanical metamaterial unit according to claim 1, characterized in that, The first intermediate straight segment has the same thickness as the first and second arc segments, the second intermediate straight segment has the same thickness as the third and fourth arc segments, and the thickness of the first intermediate straight segment is less than the thickness of the second intermediate straight segment.

3. The mechanical metamaterial unit according to claim 1, characterized in that, The height of the first support member is the same as the height of the second support member.

4. The mechanical metamaterial unit according to claim 1, characterized in that, The first arc segment has the same radius as the second, third, and fourth arc segments.

5. A mechanical metamaterial structure, characterized in that, It includes a first connector and a second connector, with a plurality of mechanical metamaterial units as described in any one of claims 1-4 disposed between the first connector and the second connector, the first connector being connected to the base of the plurality of mechanical metamaterial units, and the second connector being connected to the top cover of the plurality of mechanical metamaterial units.

6. The mechanical metamaterial structure according to claim 5, characterized in that, The first connector includes a first connecting plate and a second connecting plate arranged in a cross pattern, with the middle portion of the first connecting plate connected to the middle portion of the second connecting plate. The second connector includes a third connecting plate and a fourth connecting plate arranged in a cross pattern, with the middle portion of the third connecting plate connected to the middle portion of the fourth connecting plate. The extension direction of the first connecting plate is parallel to the extension direction of the third connecting plate. A plurality of mechanical metamaterial units are provided between the first connecting plate and the third connecting plate. The extension direction of the second connecting plate is parallel to the extension direction of the fourth connecting plate. A plurality of mechanical metamaterial units are provided between the second connecting plate and the fourth connecting plate.

7. The mechanical metamaterial structure according to claim 6, characterized in that, The first connecting plate has a first groove with an opening facing the second connecting plate in its middle part, and the second connecting plate has a second groove with an opening facing the first connecting plate in its middle part. The first groove engages with the bottom of the second groove, and the second groove engages with the bottom of the first groove. The third connecting plate has a third groove with an opening facing the fourth connecting plate in its middle part, and the fourth connecting plate has a fourth groove with an opening facing the third connecting plate in its middle part. The third groove engages with the bottom of the fourth groove, and the fourth groove engages with the bottom of the third groove.

8. The mechanical metamaterial structure according to claim 5, characterized in that, The plurality of mechanical metamaterial units are symmetrically arranged about the centerline of the first connector.

9. The mechanical metamaterial structure according to claim 5, characterized in that, It also includes a limiting post disposed between the first connector and the second connector, the limiting post being connected to the first connector or the second connector, and the height of the first support and the second support being greater than the height of the limiting post.

10. The mechanical metamaterial structure according to claim 9, characterized in that, Multiple mechanical metamaterial units are arranged at intervals in the circumferential direction of the limiting post.

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