Mechanical metamaterial unit, mechanical metamaterial structure and mechanical metamaterial

Abstract

The application discloses a mechanical metamaterial unit, a mechanical metamaterial structure and a mechanical metamaterial. The mechanical metamaterial unit comprises a base, a first supporting beam, a second supporting beam and a top cover, the first supporting beam and the second supporting beam are arranged at intervals in the length direction of the base, the bottom end of the first supporting beam and the bottom end of the second supporting beam are connected with the base, the rigidity of the first supporting beam is smaller than that of the second supporting beam, and the top end of the first supporting beam and the top end of the second supporting beam are connected with the top cover. The mechanical metamaterial unit of the application has the characteristics of simple and compact structure, strong bearing capacity, significant energy consumption effect, excellent buffering performance and reusability.

Description

Technical Field

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

[0002] In the engineering field, impact loads are a common cause of damage, posing a potential threat to the normal operation of instruments, equipment, and engineering structures. When subjected to impact, instruments may experience component failure and inaccurate data, while engineering structures may suffer a sharp decline in local or overall strength, or even complete failure, leading to personal injury and property damage.

[0003] Mechanical metamaterials are a class of artificial materials with unique properties achieved through the design of microstructures, exhibiting extraordinary mechanical properties not found in conventional materials. In the field of energy dissipation and buffering, mechanical metamaterials are mainly divided into two categories: non-recoverable metamaterials and recoverable metamaterials. Non-recoverable metamaterials primarily utilize plastic deformation to dissipate energy from impacts, often facing the problem of non-reusability. Recoverable metamaterials, on the other hand, utilize elastic deformation to absorb energy, are reusable, and have low maintenance costs, thus attracting considerable attention. However, currently existing recoverable metamaterials have unsatisfactory energy dissipation performance.

[0004] This shows that existing mechanical metamaterials still need improvement. 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, a mechanical metamaterial structure, and a mechanical metamaterial, which has significant energy dissipation effects and is reusable.

[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 beam and a second support beam are provided at intervals along the length of the base. The bottom ends of the first support beam and the second support beam are both connected to the base. The stiffness of the first support beam is less than that of the second support beam.

[0009] The top cover is connected to the top ends of both the first and second support beams.

[0010] Wherein, the height of both the first support beam and the second support beam is L, the longitudinal section profile of the first support beam includes a first side curve, and the longitudinal section profile of the second support beam includes a second side curve. The expression of the first side curve is:

[0011]

[0012] In equation (Ⅰ), A1 is a constant and A1>0, x1 is the coordinate of the first side curve on the X-axis and x1>0, and w1 is the coordinate of the first side curve on the W-axis;

[0013] The expression for the second lateral curve is:

[0014]

[0015] In equation (II), A2 is a constant and A2 > 0, x2 is the coordinate of the second side curve on the X-axis and x2 > 0, and w2 is the coordinate of the second side curve on the W-axis.

[0016] According to the above embodiments of the mechanical metamaterial unit of the present invention, by arranging a first support beam and a second support beam at intervals along the length direction of the base, and with the bottom ends of both the first and second support beams connected to the base and the top ends of both the first and second support beams connected to the top cover, the mechanical metamaterial unit has a simple and compact structure that is easy to manufacture. When compressed along a direction perpendicular to the base or top cover, the first and second support beams change from an initial state to a buckling deformation state in opposite directions, and then enter a state of mutual contact. In this contact state, the strength of the mechanical metamaterial unit is enhanced, thus possessing a strong load-bearing capacity. Subsequently, because the stiffness of the first support beam is less than that of the second support beam, the first support beam undergoes a buckling mode change under the compression of the second support beam. Finally, the first support beam undergoes a sudden jump, converting its strain energy into kinetic energy release. The expression for the first side curve of the longitudinal section profile of the first support beam is: The expression for the second side curve of the longitudinal section profile of the second support beam is: Significant energy dissipation can be achieved, thus this mechanical metamaterial unit exhibits excellent buffering performance. After a sudden jump, the first and second support beams buckle in the same direction. During unloading, the first and second support beams remain buckled in the same direction until they fully return to their initial state. Therefore, this mechanical metamaterial unit is reusable. Thus, the mechanical metamaterial unit of this invention has a simple and compact structure, strong load-bearing capacity, significant energy dissipation effect, excellent buffering performance, and reusability.

[0017] In addition, the mechanical metamaterial unit 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 support beam includes: two first support plates, which are spaced apart along the length of the base; and a first connecting plate, which is disposed between the two first support plates, with both ends of the first connecting plate connected to the two first support plates respectively. This further improves the energy dissipation effect of the mechanical metamaterial unit.

[0019] In some embodiments of the present invention, the second support beam includes: two second support plates, which are spaced apart along the length of the base; and a second connecting plate disposed between the two second support plates, with both ends of the second connecting plate connected to the two second support plates respectively. This further improves the energy dissipation effect of the mechanical metamaterial unit.

[0020] In some embodiments of the present invention, the thickness of the first support plate is less than the thickness of the second support plate. This is beneficial for achieving a significant energy-saving effect.

[0021] In some embodiments of the present invention, the ratio of A1 to L in formula (Ⅰ) is ≤1%. This is beneficial for achieving significant energy-saving effects.

[0022] In some embodiments of the present invention, the ratio of A2 to L in formula (II) is ≤1%. This is beneficial for achieving significant energy-saving effects.

[0023] In a second aspect, the present invention proposes a mechanical metamaterial structure. According to an embodiment of the present invention, the mechanical metamaterial structure comprises a plurality of the aforementioned mechanical metamaterial units. Therefore, the mechanical metamaterial structure has high load-bearing capacity, significant energy dissipation effect, and also features low requirements on the number of mechanical metamaterial units and reusability.

[0024] In addition, the mechanical metamaterial structure according to the above embodiments of the present invention may also have the following additional technical features:

[0025] In some embodiments of the present invention, the above-mentioned mechanical metamaterial structure further includes a base plate and a top plate, with multiple mechanical metamaterial units disposed between the base plate and the top plate. The base is connected to the base plate, and the top cover is connected to the top plate. This further improves the load-bearing capacity and energy dissipation effect of the mechanical metamaterial structure.

[0026] In some embodiments of the present invention, the mechanical metamaterial units are spaced apart circumferentially along the base plate. This improves the reusability of the mechanical metamaterial structure.

[0027] In some embodiments of the present invention, the above-described mechanical metamaterial structure further includes a limiting post connected to the base plate, wherein the heights of the first support beam and the second support beam are both greater than the height of the limiting post. This improves the reusability of the mechanical metamaterial structure.

[0028] In some embodiments of the present invention, the base plate is provided with a first slot, the base engages with the first slot, the top plate is provided with a second slot, and the top cover engages with the second slot. This further improves the load-bearing capacity and energy dissipation effect of the mechanical metamaterial structure.

[0029] In some embodiments of the present invention, both the base plate and the top plate are provided with through holes. This facilitates the assembly and maintenance of the mechanical metamaterial structure.

[0030] In a third aspect, the present invention proposes a mechanical metamaterial. According to an embodiment of the present invention, the mechanical metamaterial comprises a plurality of the aforementioned mechanical metamaterial structures arranged sequentially from top to bottom. Therefore, the mechanical metamaterial exhibits strong load-bearing capacity, significant energy dissipation effect, and also has the characteristics of low requirement for the number of mechanical metamaterial units and reusability.

[0031] In addition, the mechanical metamaterial according to the above embodiments of the present invention may also have the following additional technical features:

[0032] In some embodiments of the present invention, in the plurality of said mechanical metamaterial structures, the stiffness of the first support beam of each said mechanical metamaterial structure is different from the stiffness of the first support beam of the other mechanical metamaterial structures. Therefore, it is possible to respond to impacts of different intensities and achieve buffering and energy dissipation.

[0033] In some embodiments of the present invention, in the plurality of said mechanical metamaterial structures, the stiffness of the second support beam of each said mechanical metamaterial structure is different from the stiffness of the second support beam of the other mechanical metamaterial structures. Therefore, it is possible to respond to impacts of different intensities and achieve buffering and energy dissipation.

[0034] 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

[0035] 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:

[0036] Figure 1 This is a schematic diagram of the structure of a mechanical metamaterial unit according to an embodiment of the present invention;

[0037] Figure 2 This is a deformation diagram of a mechanical metamaterial unit according to an embodiment of the present invention;

[0038] Figure 3 This is a schematic diagram of a mechanical metamaterial structure according to an embodiment of the present invention;

[0039] Figure 4 This is a schematic diagram of the structure of a mechanical metamaterial according to an embodiment of the present invention;

[0040] Figure 5 This is a front view of a mechanical metamaterial according to an embodiment of the present invention;

[0041] Figure 6 This is a force-displacement curve of the mechanical metamaterial unit in Example 1;

[0042] Figure 7 This is the force-displacement curve of the mechanical metamaterial in Example 2.

[0043] Figure label:

[0044] 1000 - Mechanical metamaterial; 100 - Mechanical metamaterial structure; 10 - Mechanical metamaterial unit; 11 - Base; 12 - First support beam; 121 - First side curve; 122 - First support plate; 123 - First connecting plate; 13 - Second support beam; 131 - Second side curve; 132 - Second support plate; 133 - Second connecting plate; 14 - Top cover; 20 - Bottom plate; 30 - Top plate; 40 - Screw; 50 - Through hole; 60 - Limiting post. Detailed Implementation

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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 beam 12, a second support beam 13, and a top cover 14. The first support beam 12 and the second support beam 13 are spaced apart along the length of the base 11. The bottom ends of both the first support beam 12 and the second support beam 13 are connected to the base 11. The stiffness of the first support beam 12 is less than that of the second support beam 13. The top ends of both the first support beam 12 and the second support beam 13 are connected to the top cover 14. The height of both the first support beam 12 and the second support beam 13 is L. The longitudinal section profile of the first support beam 12 includes a first side curve 121, and the longitudinal section profile of the second support beam 13 includes a second side curve 131. The expression for the first side curve 121 is:

[0051]

[0052] In equation (Ⅰ), A1 is a constant and A1 > 0, x1 is the coordinate of the first side curve 121 on the X-axis and x1 > 0, and w1 is the coordinate of the first side curve 121 on the W-axis; the expression for the second side curve 131 is:

[0053]

[0054] In equation (II), A2 is a constant and A2 > 0, x2 is the coordinate of the second side curve 131 on the X-axis and x2 > 0, and w2 is the coordinate of the second side curve 131 on the W-axis.

[0055] According to the above embodiment of the mechanical metamaterial unit 10 of the present invention, by arranging a first support beam 12 and a second support beam 13 at intervals along the length direction of the base 11, and with the bottom ends of both the first support beam 12 and the second support beam 13 connected to the base 11 and the top ends of both the first support beam 12 and the second support beam 13 connected to the top cover 14, the mechanical metamaterial unit 10 has a simple and compact structure and is easy to manufacture; Reference Figure 2 When compressed along a direction perpendicular to the base 11 or the top cover 14, the first support beam 12 and the second support beam 13 change from the initial state a1 to a buckling deformation state in opposite directions, and then enter a state b1 of mutual contact. In the state of mutual contact, the strength of the mechanical metamaterial unit 10 is enhanced, thus possessing a stronger load-bearing capacity. Subsequently, since the stiffness of the first support beam 12 is less than that of the second support beam 13, the first support beam 12 undergoes a buckling mode change under the compression of the second support beam 13, forming state c1. Finally, the first support beam 12 undergoes a sudden jump (i.e., a sudden elastic change), converting its strain energy into kinetic energy and releasing it. The expression for the first side curve 121 of the longitudinal section profile of the first support beam 12 is: The expression for the second side curve 131 of the longitudinal section profile of the second support beam 13 is as follows: Significant energy dissipation can be achieved, thus the mechanical metamaterial unit 10 has excellent buffering performance. After a sudden jump, the first support beam 12 and the second support beam 13 form a buckling state d1 in the same direction. During unloading, the first support beam 12 and the second support beam 13 remain in the same buckling state until they fully recover to the initial state a1. Therefore, the mechanical metamaterial unit 10 is reusable. Thus, the mechanical metamaterial unit 10 of the present invention has a simple and compact structure, strong load-bearing capacity, significant energy dissipation effect, excellent buffering performance, and reusability.

[0056] According to an embodiment of the present invention, reference Figure 1The first support beam 12 may include two first support plates 122 and a first connecting plate 123. The two first support plates 122 are spaced apart along the length of the base 11, and the first connecting plate 123 is disposed between the two first support plates 122. Both ends of the first connecting plate 123 are connected to the two first support plates 122 respectively. The inventors have discovered that by connecting the two first support plates 122 to the first connecting plate 123 respectively, a first support beam 12 with a hollow structure can be formed, thereby further improving the energy dissipation effect of the mechanical metamaterial unit 10.

[0057] According to an embodiment of the present invention, reference Figure 1 The second support beam 13 may include two second support plates 132 and a second connecting plate 133. The two second support plates 132 are spaced apart along the length of the base 11, and the second connecting plate 133 is disposed between the two second support plates 132. Both ends of the second connecting plate 133 are connected to the two second support plates 132 respectively. Specifically, by connecting the two second support plates 132 to the second connecting plate 133 respectively, a second support beam 13 with a hollow structure can be formed, thereby further improving the energy dissipation effect of the mechanical metamaterial unit 10.

[0058] According to an embodiment of the present invention, the thickness of the first support plate 122 can be less than the thickness of the second support plate 132. This allows the stiffness of the first support beam 12 to be less than the stiffness of the second support beam 13. After the first support beam 12 and the second support beam 13 enter a state of mutual contact, the first support beam 12 can undergo buckling mode changes under the compression of the second support beam 13 and experience a sudden jump, converting its strain energy into kinetic energy release, thereby achieving a significant energy dissipation effect.

[0059] According to an embodiment of the present invention, in the above formula (Ⅰ), the ratio of A1 to L is ≤1%. Specifically, by controlling the ratio of A1 to L within the above range, it is further beneficial for the first support beam 12 to undergo buckling mode changes under the compression of the second support beam 13 and to undergo a sudden jump, converting its own strain energy into kinetic energy release, thereby achieving a significant energy dissipation effect.

[0060] According to an embodiment of the present invention, in the above formula (II), the ratio of A2 to L is ≤1%. Specifically, by controlling the ratio of A2 to L within the above range, it is further beneficial for the second support beam 13 to compress the first support beam 12, causing the first support beam 12 to undergo a buckling mode change and a sudden jump, converting its own strain energy into kinetic energy release, thereby achieving a significant energy dissipation effect.

[0061] It should be noted that the materials of the base, the first support beam, the second support beam, and the top cover 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).

[0062] 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 may include multiple of the aforementioned mechanical metamaterial units 10. Therefore, the mechanical metamaterial structure 100 has strong load-bearing capacity, significant energy dissipation effect, and also features low requirements for the number of mechanical metamaterial units and reusability. It should be noted that the characteristics and advantages described above for the mechanical metamaterial units also apply to this mechanical metamaterial structure, and will not be repeated here.

[0063] According to an embodiment of the present invention, the above-mentioned mechanical metamaterial structure 100 further includes a base plate 20 and a top plate 30, with multiple mechanical metamaterial units 10 disposed between the base plate 20 and the top plate 30. A base 11 is connected to the base plate 20, and a top cover 14 is connected to the top plate 30. Specifically, the base plate 20 and the top plate 30 can serve as a frame for mounting the mechanical metamaterial units 10, providing a fixing function for the mechanical metamaterial units 10, thereby further improving the load-bearing capacity and energy dissipation effect of the mechanical metamaterial structure 100. It should be noted that those skilled in the art can select the shape of the base plate 20 and the top plate 30 according to actual needs, as long as they can fix the mechanical metamaterial units 10. As a specific example, both the base plate 20 and the top plate 30 are circular.

[0064] According to an embodiment of the present invention, the mechanical metamaterial units 10 are spaced apart circumferentially along the base plate 20. This helps to disperse the impact force received by the mechanical metamaterial structure 100, making it easier to return to its initial state, thereby improving the reusability of the mechanical metamaterial structure 100.

[0065] According to an embodiment of the present invention, a first slot (not shown) is provided on the base plate 20, and the base 11 is engaged with the first slot. A second slot (not shown) is provided on the top plate 30, and the top cover 14 is engaged with the second slot. According to a specific embodiment of the present invention, threaded holes (not shown) are provided on the base 11, the base plate 20, the top cover 14, and the top plate 30. The base 11 is connected to the base plate 20 by screws 40, and the top cover 14 is connected to the top plate 30 by screws 40. This improves the stability of the mechanical metamaterial structure 100, thereby enhancing its load-bearing capacity and energy dissipation effect.

[0066] According to an embodiment of the present invention, both the base plate 20 and the top plate 30 are provided with through holes 50. This facilitates the insertion of installation tools, thereby facilitating the assembly and maintenance of the mechanical metamaterial structure 100.

[0067] According to an embodiment of the present invention, the mechanical metamaterial structure 100 may further include a limiting post 60 connected to the base plate 20. The height of the first support beam 12 and the height of the second support beam 13 are both greater than the height of the limiting post 60. This helps to limit the deformation of the first support beam 12 after a sudden jump, making it easier to return to its initial state, thereby improving the reusability of the mechanical metamaterial structure 100. According to a specific embodiment of the present invention, multiple mechanical metamaterial units 10 are arranged circumferentially around the limiting post 60 along the base plate 20. This further helps to disperse the impact force received by the mechanical metamaterial structure 100, making it easier to return to its initial state, thereby improving the reusability of the mechanical metamaterial structure 100.

[0068] It should be noted that the materials of the base plate, top plate, and limiting posts are not particularly limited, and 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 materials (such as aluminum alloy).

[0069] In a third aspect, the present invention proposes a mechanical metamaterial. According to an embodiment of the invention, reference is made to... Figure 4 and Figure 5 The mechanical metamaterial 1000 comprises multiple mechanical metamaterial structures 100 arranged sequentially from top to bottom. Therefore, the mechanical metamaterial 1000 exhibits strong load-bearing capacity, significant energy dissipation effect, and also has the characteristics of low requirement for the number of mechanical metamaterial units and reusability. It should be noted that the features and advantages described above for the mechanical metamaterial units and mechanical metamaterial structures also apply to this mechanical metamaterial, and will not be repeated here. According to a specific embodiment of the present invention, the mechanical metamaterial 1000 can be cylindrical or frustum-shaped.

[0070] According to an embodiment of the present invention, in two adjacent mechanical metamaterial structures 100, the top plate 30 of the lower mechanical metamaterial structure 100 can serve as the bottom plate of the upper mechanical metamaterial structure 100, thereby facilitating installation and reducing costs.

[0071] According to an embodiment of the present invention, in a plurality of metamaterial structures 100, the stiffness of the first support beam 12 of each metamaterial structure 100 is different from the stiffness of the first support beam 12 of the other metamaterial structures 100. Therefore, the load-bearing capacity and energy dissipation effect of each metamaterial structure 100 are different, thereby enabling it to respond to impacts of different intensities and achieve buffering and energy dissipation. Specifically, the stiffness of the first support beam 12 can be adjusted by changing the thickness of the first support plate 122 in the first support beam 12.

[0072] According to an embodiment of the present invention, in a plurality of mechanical metamaterial structures 100, the stiffness of the second support beam 13 of each mechanical metamaterial structure 100 is different from the stiffness of the second support beam 13 of the other mechanical metamaterial structures. Therefore, the load-bearing capacity and energy dissipation effect of each mechanical metamaterial structure 100 are different, thereby enabling it to respond to impacts of different intensities and achieve buffering and energy dissipation. Specifically, the stiffness of the second support beam 13 can be adjusted by changing the thickness of the second support plate 122 in the second support beam 13.

[0073] 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.

[0074] Example 1

[0075] refer to Figure 1 The mechanical metamaterial unit 10 includes a base 11, a first support beam 12, a second support beam 13, and a top cover 14, all integrally formed from polylactic acid (PLA). The first support beam 12 and the second support beam 13 are spaced apart along the length of the base 11. The bottom ends of both the first and second support beams are connected to the base 11. The stiffness of the first support beam 12 is less than that of the second support beam 13. The top ends of both the first and second support beams are connected to the top cover 14. The height L of both the first and second support beams 12 and 13 is 100 mm. The longitudinal profile of the first support beam 12 includes a first side curve 121, and the longitudinal profile of the second support beam 13 includes a second side curve 131. The expression for the first side curve 121 is:

[0076]

[0077] In equation (Ⅰ), A1 = 0.2 mm, x1 is the coordinate of the first side curve 121 on the X-axis and x1 > 0, w1 is the coordinate of the first side curve 121 on the W-axis; the expression for the second side curve 131 is:

[0078]

[0079] In formula (II), A2 = 0.5 mm, x2 is the coordinate of the second side curve 131 on the X-axis and x2 > 0, and w2 is the coordinate of the second side curve 131 on the W-axis.

[0080] The first support beam 12 includes two first support plates 122 and a first connecting plate 123. The two first support plates 122 are spaced apart along the length of the base 11. The first connecting plate 123 is disposed between the two first support plates 122, and its two ends are connected to the two first support plates 122 respectively. The thickness t1 of the first support plate 122 is 1 mm, and the length d of the first connecting plate 123 is 3 mm and its width D is 2 mm. The second support beam 13 includes two second support plates 132 and a second connecting plate 133. The two second support plates 132 are spaced apart along the length of the base 11. The second connecting plate 133 is disposed between the two second support plates 132, and its two ends are connected to the two second support plates 132 respectively. The thickness t2 of the second support plate 132 is 1.6 mm, and the length d of the second connecting plate 133 is 3 mm and its width D is 2 mm. The distance S between the first support beam 12 and the second support beam 13 is 12mm, and the out-of-plane thickness b (the dimension along the plane perpendicular to the X-axis and W-axis) of the entire mechanical metamaterial unit 10 is 15mm.

[0081] 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 beam 12 and the second support beam 13 transition from the initial state a1 to a buckling deformation state in opposite directions, and then enter a state b1 of mutual contact. In the state of mutual contact, the strength of the mechanical metamaterial unit 10 is enhanced, thus possessing a stronger load-bearing capacity. Subsequently, since the stiffness of the first support beam 12 is less than that of the second support beam 13, the first support beam 12 undergoes a buckling mode change under the compression of the second support beam 13, forming state c1. Finally, the first support beam 12 undergoes a sudden jump, converting its strain energy into kinetic energy and releasing it, achieving a significant energy dissipation effect (the energy dissipated in this process is...). Figure 6 (represented by the area of ​​the filled region), thus, the mechanical metamaterial unit 10 has excellent buffering performance. After the sudden jump, the first support beam 12 and the second support beam 13 form a buckling state d1 in the same direction. During unloading, the first support beam 12 and the second support beam 13 remain in a buckling state 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.

[0082] Example 2

[0083] refer to Figure 4 and Figure 5The mechanical metamaterial includes three mechanical metamaterial structures 100 arranged sequentially from top to bottom. Each mechanical metamaterial structure 100 includes a base plate 20, a top plate 30, a limiting post 60, and six mechanical metamaterial units 10. The base plate 20, top plate 30, and limiting post 60 are all made of PLA. The structure of the three mechanical metamaterial units 10 is the same as in Example 1, except that the height L of the first support beam 12 and the second support beam 13 in the three mechanical metamaterial structures 100 is 50mm, A1 = 0.1mm, A2 = 0.25mm, the length d of the first connecting plate 123 is 1.5mm, and the width D is 1mm. The length of the second connecting plate 133 is... The diameter d is 1.5 mm, the width D is 1 mm, the distance S between the first support beam 12 and the second support beam 13 is 6 mm, the out-of-plane thickness b of the entire mechanical metamaterial unit 10 is 7.5 mm, the thickness t1 of the first support plate 122 in the upper mechanical metamaterial structure 100 is 0.3 mm, the thickness t2 of the second support plate 132 is 0.6 mm, the thickness t1 of the first support plate 122 in the middle mechanical metamaterial structure 100 is 0.4 mm, the thickness t2 of the second support plate 132 is 0.8 mm, and the thickness t1 of the first support plate 122 in the lower mechanical metamaterial structure 100 is 0.5 mm, and the thickness t2 of the second support plate 132 is 1 mm.

[0084] The limiting post 60 and six mechanical metamaterial units 10 are all disposed between the base plate 20 and the top plate 30. The base plate 20 has a first slot (not shown), and the base 11 is engaged with the first slot. The top plate 30 has a second slot (not shown), and the top cover 14 is engaged with the second slot. The base 11, base plate 20, top cover 14, and top plate 30 are all provided with threaded holes (not shown). The base 11 is connected to the base plate 20 by screws 40, and the top cover 14 is connected to the top plate 30 by screws 40. Both the base plate 20 and the top plate 30 are provided with through holes 50. The limiting post 60 is connected to the base plate 20. The height of the first support beam 12 and the height of the second support beam 13 are both greater than the height of the limiting post 60. The six mechanical metamaterial units 10 are evenly spaced around the limiting post 60 along the circumference of the base plate 20.

[0085] The force-displacement curves of the aforementioned mechanical metamaterials under axial compression are as follows: Figure 7 As shown.

[0086] Depend on Figure 7 It can be seen that by rationally designing the thickness of the first and second support plates in each layer of the mechanical metamaterial, the force-displacement curve of this mechanical metamaterial can have multiple hysteresis regions with different peak values ​​and different sizes (i.e., Figure 7 The filling area in the middle can respond to impacts of different intensities and achieve buffering and energy dissipation.

[0087] As can be seen from Examples 1-2, the mechanical metamaterial unit of the present invention has a simple and compact structure, strong load-bearing capacity, significant energy dissipation effect, excellent buffering performance and reusability. By rationally designing the thickness of the first support plate and the second support plate in each layer of the mechanical metamaterial unit, the mechanical metamaterial of the present invention can achieve programmable mechanical response and dissipate the energy of impacts of different intensities.

[0088] 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.

[0089] 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 beam and a second support beam are provided at intervals along the length of the base. The bottom ends of the first support beam and the second support beam are both connected to the base. The stiffness of the first support beam is less than that of the second support beam. The top cover is connected to the top ends of both the first and second support beams. The heights of the first support beam and the second support beam are both L The longitudinal section profile of the first support beam includes a first side curve, and the longitudinal section profile of the second support beam includes a second side curve. The expression for the first side curve is: （Ⅰ）， In formula (Ⅰ), A 1 is a constant and A 1>0, x 1 represents the coordinate of the first side curve on the X-axis and x 1>0, w 1 represents the coordinate of the first side curve on the W-axis; The expression for the second lateral curve is: （Ⅱ）， In formula (II), A 2 is a constant and A 2 > 0, x 2 is the coordinate of the second side curve on the X-axis and x 2 > 0, w 2 represents the coordinates of the second side curve on the W-axis.

2. The mechanical metamaterial unit according to claim 1, characterized in that, The first support beam includes: Two first support plates are spaced apart along the length of the base. A first connecting plate is disposed between two first support plates, and both ends of the first connecting plate are respectively connected to the two first support plates.

3. The mechanical metamaterial unit according to claim 2, characterized in that, The second support beam includes: Two second support plates are spaced apart along the length of the base. The second connecting plate is disposed between the two second support plates, and its two ends are respectively connected to the two second support plates.

4. The mechanical metamaterial unit according to claim 3, characterized in that, The thickness of the first support plate is less than the thickness of the second support plate; In formula (Ⅰ), A 1 and L The ratio is ≤1%; In formula (II), A 2 and L The ratio is ≤1%.

5. A mechanical metamaterial structure, characterized in that, It includes mechanical metamaterial units as described in any one of claims 1-4.

6. The mechanical metamaterial structure according to claim 5, characterized in that, It also includes a base plate and a top plate, with multiple mechanical metamaterial units disposed between the base plate and the top plate, the base being connected to the base plate, and the top cover being connected to the top plate; The mechanical metamaterial units are spaced apart circumferentially along the base plate.

7. The mechanical metamaterial structure according to claim 6, characterized in that, It also includes a limiting post, which is connected to the base plate, and the height of the first support beam and the height of the second support beam are both greater than the height of the limiting post.

8. The mechanical metamaterial structure according to claim 6, characterized in that, The base plate is provided with a first slot, and the base is engaged with the first slot; the top plate is provided with a second slot, and the top cover is engaged with the second slot. Both the bottom plate and the top plate are provided with through holes.

9. A mechanical metamaterial, characterized in that, It includes multiple mechanical metamaterial structures as described in any one of claims 5-8, arranged sequentially from top to bottom.

10. The mechanical metamaterial according to claim 9, characterized in that, In the plurality of mechanical metamaterial structures, the stiffness of the first support beam of each mechanical metamaterial structure is different from the stiffness of the first support beam of the other mechanical metamaterial structures; In the plurality of said mechanical metamaterial structures, the stiffness of the second support beam of each of the mechanical metamaterial structures is different from the stiffness of the second support beam of the other mechanical metamaterial structures.

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