Inertia-super-damping coupling synergistic unit cell and local resonance metamaterial

Abstract

A frame comprises an inner shell and an outer shell, a positive stiffness-negative stiffness unit comprises a second sliding block, a first sliding block and a second connecting rod, the second sliding block extends into the inner shell in a sliding mode, the first sliding block is arranged in the inner shell, and the second connecting rod is connected with the first sliding block. The extending-in end of the second sliding block is hinged to the first sliding block through a second connecting rod, the extending-out end of the second sliding block is fixedly connected with the outer shell through an elastic rod, and the other end, extending out of the second sliding block, of the inner shell is fixedly connected with the outer shell through an elastic rod. The lever rotation inerter unit comprises a first connecting rod and a fan-shaped disc, the fan-shaped disc is rotationally arranged in the inner shell, the other end, hinged to the second sliding block, of the first sliding block is hinged to the fan-shaped disc through the first connecting rod, the eddy current super-damping unit comprises magnets, and the fan-shaped disc is arranged between the magnets. Compared with the prior art, the method can realize synergistic control of structural vibration under broadband multi-dimensional excitation.

Description

Technical Field

[0001] The invention belongs to the technical field of civil engineering, and relates to an inertial-super damping coupling synergistic unit cell and a local resonance metamaterial. Background Art

[0002] Metamaterials are new artificial composite periodic materials based on artificial structural unit cells, which can achieve mechanical properties that traditional natural materials cannot achieve. The sensitivity of metamaterial periodic structures to dynamic loads makes it possible to achieve vibration and noise control. Traditional local resonance metamaterials set up local resonance units wrapped by flexible materials in the unit cell structure, thereby generating a bandgap that prevents the propagation of elastic waves, which makes it possible to achieve broadband bandgaps and construct metamaterials in the field of earthquake engineering. However, existing local resonance metamaterials generally have the problem of too narrow bandgaps; especially in the field of seismic wave modulation dominated by broadband components, achieving broadband bandgaps often requires increasing the additional mass of the resonance unit, reducing the internal stiffness of the resonance unit, and increasing the equivalent damping effect of the resonance unit. In addition, compared with Bragg-type metamaterials, although local resonance metamaterials are more suitable for vibration reduction in the extremely low frequency range, the elastic waves (especially impact effects) are not effectively attenuated within the resonance band gap. Existing metamaterial technology is difficult to simultaneously achieve damping efficiency enhancement under the premise of local resonance, large mass and small deformation under engineering conditions. It is urgent to develop new metamaterial units with wide-band gaps and high attenuation coefficients.

[0003] Patent CN114658782A discloses a bidirectional buffering energy-absorbing local resonance metamaterial with enhanced performance, including a multicellular local resonance metamaterial structure formed by a plurality of unit cells arranged periodically; the unit cell is composed of a cross-curved beam, a bidirectional ring, a spiral rod, a rectangular frame and a connecting rod, the rectangular frame is composed of a straight beam, the cross-curved beam is composed of two curved beams crossed, two groups of cross-curved beams are installed in two opposite surfaces of the frame, the ends of the cross-curved beams are fixedly connected to the rectangular frame, the two groups of cross-curved beams are parallel to each other, the upper and lower end faces of the bidirectional rings in the unit cell are respectively fixedly connected to the middle of the two groups of cross-curved beams by spiral rods, different unit cells are connected to the intersection of the cross-curved beams by straight rods in the vertical direction, and are connected by sharing the rectangular frame in the horizontal direction, and multiple unit cells are arranged periodically to form a multicellular local resonance metamaterial structure. Although this patent enhances the energy absorption capacity of the metamaterial by superimposing cross-curved beams, on the one hand, the deformation of the cross-curved beams of this patent is consistent with the external displacement, and does not have internal vibration freedom and additional local resonant mass, which weakens the deformation amplification and energy absorption efficiency of the local resonant mass under small deformation conditions. On the other hand, the metamaterial of this patent lacks enhanced energy-absorbing units under small deformation conditions, and cannot achieve deformation amplification of the energy-absorbing units, making it difficult to quickly dissipate the absorbed energy, limiting its transient control effect on impact and its energy dissipation and vibration reduction capabilities for steady-state vibrations.

[0004] Patent CN107701635A discloses a low-frequency broadband local resonance structure with super damping characteristics, including a diamond frame, wherein the first end of the diamond frame is connected to the base beam through a rubber block; a rubber strip is arranged on the short diagonal line in the diamond frame, one end of the rubber strip is connected to the first end of the diamond frame, and the other end is connected to the second end of the diamond frame; mass blocks are arranged at both ends of the diamond frame, and the structure is periodically attached to the beam unit. Although the patent realizes additional damping by arranging rubber strips on the diamond diagonal lines and attaches mass by arranging mass blocks at both ends of the diamond, the local resonance structure constructed by the patent does not have the ability of mass secondary amplification and eddy current super damping based on flexible levers, resulting in its weak ability to expand the broadband band gap, and the patent also does not have internal vibration freedom, which weakens the deformation amplification of the local resonance mass and the deformation amplification of the energy consumption unit under small deformation conditions.

[0005] Patent CN111609070A discloses a metamaterial device with wide low-frequency vibration isolation and noise reduction performance, including a large mass block, a small mass block and a connecting rod; the large mass block and the small mass block are both rectangular structures composed of aluminum, the large mass block and the small mass block are alternately hinged in sequence through the connecting rod, each hinge point on the large mass block and the small mass forms a quasi-zero stiffness characteristic, and together constitutes a linear double-oscillator periodic structure; the linear double-oscillator periodic structure can form at least two band gap structures, and the quasi-zero stiffness characteristic of the metamaterial device can achieve a strong attenuation effect in the ultra-low frequency range; a large mass block, a small mass block and a large mass block hinged in sequence form a unit cell structure, each large mass block and small mass block are provided with four through connection holes, a hinge shaft is installed in the connection hole, and the same side of an adjacent large mass block and a small mass block is hinged by two staggered connecting rods. Although the patent establishes a metamaterial configuration by staggered arrangement of mass blocks, the additional mass of the patent is small and it is difficult to further increase the additional mass of the resonance unit, which makes the metamaterial of the patent insufficient to achieve the wide-band gap required for engineering vibration isolation. In addition, the lack of damping units also limits the metamaterial's transient control effect on impact and its ability to dissipate energy and reduce vibrations in steady-state vibrations. Summary of the invention

[0006] The purpose of the present invention is to provide an inertial-super damping coupling synergistic unit cell and a local resonance metamaterial in order to overcome at least one defect of the above-mentioned prior art. The present invention can achieve synergistic control of structural vibration under broadband multi-dimensional excitation.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] One of the technical solutions of the present invention is to provide an inertia-super damping coupling synergistic unit cell, which includes a positive stiffness-negative stiffness unit, a lever rotation inertia unit, an eddy current super damping unit and a frame.

[0009] The frame includes an inner shell and an outer shell, wherein the inner shell is arranged in a sliding connection inside the outer shell, and the outer shell provides a bearing capacity for the unit cell.

[0010] The positive stiffness-negative stiffness unit comprises a second slider, a first slider and a second connecting rod, the second slider slides and extends into the inner shell, the inner shell is provided with the first slider, the extending end of the second slider is hinged to the first slider through the second connecting rod, and the extending end is fixedly connected to the outer shell through an elastic rod, and the other end of the inner shell where the second slider extends is fixedly connected to the outer shell through the elastic rod,

[0011] The second connecting rod is configured as a diamond connecting rod mechanism including four connecting rods hinged to each other.

[0012] The lever rotation inertia unit includes a first connecting rod and a sector disk. The sector disk is rotatably arranged in the inner shell. The other end of the first slider hinged to the second slider is hinged to the sector disk through the first connecting rod.

[0013] The eddy current super damping unit comprises magnets, and the sector disk is arranged between the magnets;

[0014] When an external load acts on the second slider through the elastic rod, the second slider moves inward relative to the inner shell and exhibits a negative stiffness characteristic, while the second slider moves outward relative to the inner shell and exhibits a positive stiffness characteristic;

[0015] The elastic beam connecting the outer shell and the internal components on both sides has a function similar to a tuned spring, which amplifies the displacement of the slider through resonance tuning, thereby amplifying the deformation of the negative stiffness / inertia unit;

[0016] The first slider pushes the sector disk to rotate via the hinged first connecting rod, thereby achieving an inertia effect;

[0017] When the sector disk rotates under the action of the first connecting rod, the magnetic flux lines between the cutting magnets generate eddy currents. The Lorentz force generated by the interaction between the eddy current field and the magnetic field hinders the relative movement between the sector disk and the magnetic field. At the same time, the eddy currents are converted into heat energy dissipation in the sector disk, thereby providing a super damping effect.

[0018] Furthermore, the positive stiffness-negative stiffness unit also includes a connecting plate, the protruding end of the second slider is fixedly connected to the connecting plate, the connecting plate is fixedly connected to the elastic rod on the other side of the second slider, the second slider moves horizontally along the groove of the inner shell, and drives the second connecting rod of the diamond linkage mechanism to deform.

[0019] Furthermore, the elastic rods are provided in plurality, one of which is arranged on the central axis of the unit cell, and the others are symmetrically arranged on both sides of the central axis;

[0020] The elastic rods symmetrically arranged on both sides of the central axis are configured as elastic curved rods, and the distance between the connection end of the elastic curved rod close to the inner shell and the central axis is smaller than the distance between the connection end with the outer shell and the central axis. The purpose of the bending design of the elastic curved rod is to enable the elastic curved rod to have deformation ability, so that compression deformation, tensile deformation and reset can be achieved during the force process.

[0021] Furthermore, the positive stiffness-negative stiffness unit also includes a preload spring, a support rod is fixedly connected between the inner walls of the inner shell, the support rod is sleeved with a preload spring, and the two hinge points of the second connecting rod that are not hinged to the slider are respectively slidably sleeved on the support rod through a sleeve ring, so as to control the relative state of the diamond connecting rod mechanism in the unit cell, and the two hinge points of the second connecting rod that are not hinged to the slider are connected by a preload spring;

[0022] The combination of the diamond linkage mechanism and the preload spring introduces nonlinear stiffness, amplifies the deformation capacity inside the unit cell, and improves the energy dissipation capacity of the inertial capacity vibration reduction and the eddy current super damping.

[0023] As a preferred technical solution, in the initial state, the second slider and the outer shell are connected by an elastic rod and remain relatively still, the inner shell and the outer shell are connected by an elastic rod and remain relatively still, and correspondingly, the second slider and the inner shell also remain relatively still, and the stiffness of the elastic rod is greater than the stiffness of the pre-stress spring. At this time, the reaction force of the pre-stress spring can only cause a small deformation of the elastic rod, and the pre-stress length of the pre-stress spring cannot be completely released. The pre-stress spring can maintain the pre-stress state, and the diamond connecting rod mechanism of the second connecting rod is stabilized in the initial state, and the second slider, the first slider and the fan-shaped disk connected by the connecting rod all maintain a relatively static initial equilibrium state.

[0024] Furthermore, a rotating shaft is fixedly connected inside the inner shell, and the sector disk is rotatably connected to the inner shell via the rotating shaft;

[0025] The hinge point between the first connecting rod and the sector disk is not coaxial with the rotation axis of the sector disk, and is close to the rotation axis of the sector disk;

[0026] At the same time, the distance between the hinge point of the first connecting rod and the rotation axis of the fan-shaped disk is relatively close, achieving the lever mass amplification effect. The ratio of the radius of the fan-shaped disk to the distance between the hinge point of the first connecting rod and the rotation axis of the fan-shaped disk is significant for adjusting the inertia coefficient of the unit cell.

[0027] As a preferred technical solution, the hinge point of the first connecting rod on the fan-shaped disk is adjustable to achieve different proportions of inertial mass efficiency enhancement.

[0028] Furthermore, there are two fan-shaped disks arranged in opposite directions, and the other end of the first slider being hinged to the second slider is hinged to the two fan-shaped disks respectively through two first connecting rods. The two fan-shaped disks are arranged in opposite directions so that the center of gravity of the unit cell remains unchanged in the working state, and the torques formed by the rotation of the fan-shaped disks offset each other, thereby ensuring the stability of the unit cell.

[0029] Further, the eddy current super damping unit comprises a first magnet and a second magnet, and two of the first magnet and the second magnet are arranged respectively and are firmly mounted on the inner wall of the inner shell;

[0030] In the height direction, the first magnet, the sector disk, the second magnet, the sector disk and the first magnet are arranged in sequence and spaced apart, and two second magnets are arranged in the same layer;

[0031] The first magnet and the second magnet have opposite magnetic poles.

[0032] As a preferred technical solution, the first connecting rod is arranged between the sector disk and the first magnet, and the sector disk is rotationally connected to the first magnet via a rotating shaft.

[0033] Furthermore, the two sector disks are arranged in the same layer in the length direction, and the two second magnets are arranged on both sides of the sector disk;

[0034] Two sector disks are arranged in reverse symmetry on the same layer, and two second magnets are arranged on both sides of the sector disk without any overlap to form an initial state of a unit cell. The length of the first magnet is equal to the sum of the chord length corresponding to the central angle of the sector disk and the length of the two second magnets.

[0035] Furthermore, the side walls of the inner shell and the outer shell are connected by ball sliding to assist movement.

[0036] One of the technical solutions of the present invention is to provide an inertia-super damping coupling enhancement method, which uses the unit cell to perform coupling enhancement, and comprises the following steps:

[0037] When the unit cell starts to work, the external excitation is transmitted to the connecting plate through the outer shell and the elastic rod, and the connecting plate drives the second slider to move horizontally inward relative to the inner shell;

[0038] The second slider drives the diamond link mechanism of the second link to deform, and the preload spring in the diamond link mechanism promotes the deformation of the diamond link mechanism, that is, a nonlinear negative stiffness effect is generated;

[0039] When the connecting plate is horizontally displaced outward relative to the inner shell, the preload spring in the diamond link mechanism hinders the deformation of the diamond link mechanism, that is, a nonlinear positive stiffness effect is generated;

[0040] The horizontal movement of the first slider is transmitted to the sector disk through the hinged first connecting rod, pushing the sector disk to rotate, thereby generating an inertia mass enhancement effect;

[0041] When the sector disk rotates, the sector disk begins to cut the magnetic flux lines between the first magnet and the second magnet, so that the sector disk has an eddy current super damping effect;

[0042] If an oscillating external excitation is applied, the connecting plate continuously changes between horizontal displacement inward and outward relative to the inner shell, switching the corresponding nonlinear positive and negative stiffness effects, and has the ability to reciprocate energy dissipation.

[0043] One of the technical solutions of the present invention is to provide a local resonance metamaterial, which includes a plurality of the unit cells connected in series or in parallel, wherein the elastic rod realizes the local resonance tuning effect of the unit cell, cooperates with the positive stiffness-negative stiffness unit and the lever rotation inertia unit to amplify the deformation amplitude and efficiency of the eddy current super damping unit, thereby realizing the damping efficiency amplification based on the super damping, so as to enhance the peak control effect of the finite unit cell sequence on the short-time impact effect, and has a regular shell that is easy to be combined and applied in various styles;

[0044] When external excitation is input, each unit cell works in turn, which can provide a better broadband vibration reduction effect.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] (1) The metamaterial unit cell proposed in the present invention realizes the fusion of multiple mechanisms such as lever-amplified inertial mass efficiency, positive stiffness-negative stiffness adaptation and eddy current super damping, which solves the problems of the current metamaterial unit cell, such as the single form, narrow metamaterial band gap, high central frequency band, and insufficient elastic wave attenuation in the band gap. The present invention realizes the effects of ultra-wideband low-frequency band gap, eddy current super damping vibration reduction (compared with the damping efficiency enhancement of local resonance metamaterials) and nonlinear inertial energy absorption, and can realize the efficiency control of structural vibration under low-frequency, wide-band and multi-dimensional excitation.

[0047] (2) The super-damping unit cell with the inertia capacity negative stiffness lever amplification characteristic proposed in the present invention can be built into a frame periodic structure with high static bearing capacity. Based on the inertia capacity negative stiffness resonance unit and eddy current super-damping, a low-frequency broadband band gap is provided, which solves the contradiction between the static bearing capacity and the seismic isolation capability of the existing seismic isolation technology. The proposed metamaterial unit cell has the advantages of small size, standardized components and easy combination.

[0048] (3) The metamaterial unit cell proposed in the present invention is standardized in design and has a regular appearance. It can be connected in series, in parallel, and in other combinations, thereby providing specific negative stiffness values, inertia coefficients, and damping coefficients to meet the different needs of seismic isolation in engineering projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 Schematic diagram of the side cross-sectional structure of the initial state of the inertial-super damping coupling synergistic unit cell in an embodiment of the present invention;

[0050] Figure 2 AA cross-sectional structure schematic diagram of the initial state of the inertial-super damping coupling synergistic unit cell in an embodiment of the present invention;

[0051] Figure 3 BB cross-sectional structure schematic diagram of the initial state of the inertial-super damping coupling synergistic unit cell in an embodiment of the present invention;

[0052] Figure 4 Schematic diagram of the side cross-sectional structure of the initial state of the local resonance metamaterial in an embodiment of the present invention.

[0053] Description of the markings in the figure:

[0054] 1—connecting plate, 2—second slider, 3—first slider, 4—first connecting rod, 5—sector disk, 6—first magnet, 7—second magnet, 8—inner shell, 9—elastic rod, 10—outer shell, 11—ball, 12—second connecting rod, 13—preload spring, 14—rotating shaft, 15—support rod. DETAILED DESCRIPTION

[0055] The present invention is described in detail below in conjunction with specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and a specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0056] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", "third", etc. are used to describe common objects, which only refer to different instances of the same object, and are not intended to imply that the objects described in this way must adopt a given order, whether in time, space, order or any other way.

[0057] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0058] Example:

[0059] An inertial-superdamping coupling enhancement type unit cell, such as Figures 1 to 3 As shown, it includes positive stiffness-negative stiffness unit, lever rotation inertia unit, eddy current super damping unit and frame.

[0060] The frame includes an inner shell 8 and an outer shell 10. The inner shell 8 is arranged in the outer shell 10 for sliding connection. The outer shell 10 can provide bearing capacity for the unit cell.

[0061] The positive stiffness-negative stiffness unit includes a second slider 2, a first slider 3 and a second connecting rod 12. The second slider 2 slides and extends into the inner shell 8. The first slider 3 is arranged in the inner shell 8. The extending end of the second slider 2 is hinged to the first slider 3 through the second connecting rod 12, and the extending end is fixedly connected to the outer shell 10 through the elastic rod 9. The other end of the inner shell 8 extending from the second slider 2 is fixedly connected to the outer shell 10 through the elastic rod 9.

[0062] The second connecting rod 12 is configured as a diamond connecting rod mechanism including four connecting rods hinged to each other.

[0063] The lever rotation inertia unit includes a first connecting rod 4 and a sector disk 5. The sector disk 5 is rotatably arranged in the inner shell 8. The other end of the first slider 3 hinged to the second slider 2 is hinged to the sector disk 5 through the first connecting rod 4.

[0064] The eddy current super damping unit includes magnets, and the sector disk 5 is arranged between the magnets;

[0065] When an external load acts on the second slider 2 through the elastic rod 9, the second slider 2 moves to the left relative to the inner shell 8 and exhibits a negative stiffness characteristic, and the second slider 2 moves to the right relative to the inner shell 8 and exhibits a positive stiffness characteristic;

[0066] The elastic beam 9 connecting the housing 10 and the internal components on both sides has a function similar to a tuning spring, and can amplify the displacement of the slider 2 through resonance tuning, thereby amplifying the deformation of the negative stiffness / inertia unit;

[0067] The first slider 3 pushes the sector disk 5 to rotate through the hinged first connecting rod 4, thereby achieving an inertia effect;

[0068] When the sector disk 5 rotates under the action of the first connecting rod 4, the magnetic flux lines between the cutting magnets generate eddy currents. The Lorentz force generated by the interaction between the eddy current field and the magnetic field will hinder the relative movement between the sector disk 5 and the magnetic field. At the same time, the eddy currents will be converted into heat energy dissipation in the sector disk 5, thereby providing a super damping effect.

[0069] The positive stiffness-negative stiffness unit also includes a connecting plate 1, the protruding end of the second slider 2 is fixedly connected to the connecting plate 1, and the other side of the connecting plate 1 connected to the second slider 2 is fixedly connected to the elastic rod 9, and the second slider 2 can move horizontally along the slot of the inner shell 8, and drive the second connecting rod 12 of the diamond linkage mechanism to deform;

[0070] There are five elastic rods 9, one of which is arranged on the central axis of the unit cell, and four are orthogonally symmetrically arranged on both sides of the central axis;

[0071] Four elastic rods 9 symmetrically arranged on both sides of the central axis are configured as elastic curved rods. The distance between the connection end of the elastic curved rod close to the inner shell 8 and the central axis is smaller than the distance between the connection end with the outer shell 10 and the central axis. The purpose of the bending design of the elastic curved rod is to enable the elastic curved rod to have deformation ability, so that it can achieve compression deformation, tension deformation and reset during the force process;

[0072] The positive stiffness-negative stiffness unit also includes a preload spring 13. A support rod 15 is fixedly connected between the inner walls of the inner shell 8. The support rod 15 is sleeved with the preload spring 13. The two hinge points of the second connecting rod 12 that are not hinged to the slider are respectively slidably sleeved on the support rod 15 through a sleeve ring, so as to control the relative state of the diamond connecting rod mechanism in the unit cell. The two hinge points of the second connecting rod 12 that are not hinged to the slider are connected through the preload spring 13.

[0073] The combination of the diamond linkage mechanism and the preload spring 13 introduces nonlinear stiffness, amplifies the deformation capacity inside the unit cell, and improves the energy dissipation capacity of the inertia vibration reduction and the eddy current super damping;

[0074] In the initial state, the second slider 2 and the outer shell 10 are connected by the elastic rod 9 to remain relatively still, and the inner shell 8 and the outer shell 10 are connected by the elastic rod 9 to remain relatively still. Correspondingly, the second slider 2 and the inner shell 8 also remain relatively still. The stiffness of the elastic rod 9 is greater than the stiffness of the pre-stress spring 13. At this time, the reaction force of the pre-stress spring 13 can only cause a small deformation of the elastic rod 9, and the pre-stress length of the pre-stress spring 13 cannot be completely released. The pre-stress spring 13 can maintain the pre-stress state, and the diamond connecting rod mechanism of the second connecting rod 12 is stable in the initial state. The second slider 2, the first slider 3 and the fan-shaped disk 5 connected by the connecting rod all maintain a relatively still initial equilibrium state;

[0075] A rotating shaft 14 is fixedly connected inside the inner shell 8, and the sector disk 5 is rotatably connected to the inner shell 8 via the rotating shaft 14;

[0076] The hinge point between the first connecting rod 4 and the sector disk 5 is not coaxial with the rotation axis 14 of the sector disk 5 and is close to the rotation axis 14 of the sector disk 5;

[0077] At the same time, the hinge point of the first connecting rod 4 is close to the rotation axis 14 of the sector disk 5, which can achieve the lever mass amplification effect;

[0078] The hinge point of the first connecting rod 4 on the fan-shaped disk 5 is adjustable to achieve different proportions of inertia mass efficiency enhancement;

[0079] In this embodiment, the ratio of the radius of the sector disk 5 to the distance between the hinge point of the first connecting rod 4 and the rotation axis 14 of the sector disk 5 is 5. The significance of the ratio of radius to distance is to adjust the inertia coefficient of the unit cell;

[0080] There are two fan-shaped discs 5 arranged in opposite directions. The other end of the first slider 3 and the second slider 2 is hinged to the two fan-shaped discs 5 through two first connecting rods 4. The two fan-shaped discs 5 are arranged in opposite directions so that the center of gravity of the unit cell remains unchanged in the working state, and the torques formed by the rotation of the fan-shaped discs 5 offset each other, thereby ensuring the stability of the unit cell state.

[0081] The eddy current super damping unit includes a first magnet 6 and a second magnet 7, and two of the first magnet 6 and the second magnet 7 are arranged respectively and are firmly mounted on the inner wall of the inner shell 8;

[0082] In the height direction, the first magnet 6, the sector disk 5, the second magnet 7, the sector disk 5 and the first magnet 6 are arranged in sequence and spaced apart, and two second magnets 7 are arranged in the same layer;

[0083] The first connecting rod 4 is disposed between the sector disk 5 and the first magnet 6, and the sector disk 5 is rotatably connected to the first magnet 6 via a rotating shaft 14;

[0084] The magnetic pole of the first magnet 6 is selected as N (S) pole, and the magnetic pole of the second magnet 7 is selected as S (N) pole;

[0085] Two sector disks 5 are arranged in the same layer in the length direction, and two second magnets 7 are arranged on both sides of the sector disk 5;

[0086] Two sector disks 5 are arranged in the same layer in an anti-symmetrical manner, and two second magnets 7 are arranged on both sides of the sector disk 5 without any overlap to form an initial state of a unit cell. The length of the first magnet 6 is equal to the sum of the length of the chord corresponding to the central angle of the sector disk 5 and the length of the two second magnets 7.

[0087] The inner shell 8 and the side wall of the outer shell 10 are slidably connected by balls 11 to assist the movement.

[0088] In this embodiment, the material of the plate, slider, connecting rod, shell, elastic rod 9 and rotating shaft 14 is thermoplastic polyurethane elastomer, and the material of the sector disk 5, ball 11 and preload spring 13 is steel.

[0089] An inertia-super damping coupling enhancement method is provided, which uses the above-mentioned unit cell for coupling enhancement, and the specific steps are as follows:

[0090] When the unit cell starts to work, the external excitation is transmitted to the connecting plate 1 through the outer shell 10 and the elastic rod 9. The connecting plate 1 moves to the left relative to the inner shell 8 and drives the second slider 2 to move horizontally.

[0091] The second slider 2 drives the diamond link mechanism of the second link 12 to deform, and the preload spring 13 in the diamond link mechanism promotes the deformation of the diamond link mechanism, that is, a nonlinear negative stiffness effect is generated;

[0092] When the connecting plate 1 is horizontally displaced to the right relative to the inner shell 8, the preload spring 13 in the diamond link mechanism hinders the deformation of the diamond link mechanism, that is, a nonlinear positive stiffness effect is generated;

[0093] The horizontal movement of the first slider 3 is transmitted to the sector disk 5 through the hinged first connecting rod 4, pushing the sector disk 5 to rotate, thereby generating an inertia mass enhancement effect;

[0094] When the sector disk 5 rotates, the sector disk 5 starts to cut the magnetic flux lines between the first magnet 6 and the second magnet 7, so that the sector disk 5 has an eddy current super damping effect;

[0095] If an oscillating external excitation is applied, the connecting plate 1 continuously switches between horizontal displacements to the left and to the right relative to the inner shell 8, switching the corresponding nonlinear positive and negative stiffness effects, and has the ability to reciprocate energy consumption.

[0096] A local resonance metamaterial, such as Figure 4 As shown, it includes a plurality of the above-mentioned unit cells connected in series or in parallel. In this embodiment, three unit cells are preferably connected in series. The elastic rod 9 can realize the local resonance tuning effect of the unit cell, cooperate with the positive stiffness-negative stiffness unit and the lever rotation inertia unit to amplify the deformation amplitude and efficiency of the eddy current super damping unit, and then realize the damping efficiency amplification based on the super damping, so as to enhance the peak control effect of the finite unit cell sequence on the short-time impact effect. The regular shell 10 is easy to be combined and applied in various styles;

[0097] When external excitation is input, each unit cell works in turn, which can provide a better broadband vibration reduction effect;

[0098] The unit cell is simplified into a model of nonlinear inertial force, nonlinear elastic force and nonlinear damping force. Based on the model, series and parallel designs are carried out to calculate and realize specific negative stiffness values, inertia coefficients and damping coefficients under different configurations.

[0099] The present invention provides a standardized design of a metamaterial unit cell that combines negative stiffness enhancement, lever amplification enhancement, inertia capacity enhancement and super damping mechanisms, thereby realizing the mutual integration of multiple mechanisms. The negative stiffness enhancement mechanism and the lever amplification mechanism can improve the energy consumption capacity of the metamaterial unit cell, the inertia capacity enhancement mechanism can provide an excellent broadband shock absorption effect, and the super damping mechanism can reduce the peak value of the passband, thereby realizing the nonlinear shock absorption effect under a variety of enhancement mechanisms, and realizing the vibration control of the structure under multi-level coupling excitation. In addition, the metamaterial unit cell of the present invention has the advantages of small size, standardized components, and easy combination. Through mutual combination, specific negative stiffness values, inertia coefficients and damping coefficients can be achieved to meet the different needs of seismic isolation in engineering projects.

[0100] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. An inertial-super damping coupling synergistic unit cell, characterized in that: The unit cell includes positive stiffness-negative stiffness unit, lever rotation inertia unit, eddy current super damping unit and frame. The frame comprises an inner shell (8) and an outer shell (10), wherein the inner shell (8) is arranged in a sliding connection with the outer shell (10). The positive stiffness-negative stiffness unit comprises a second slider (2), a first slider (3) and a second connecting rod (12); the second slider (2) slides and extends into an inner shell (8); the first slider (3) is arranged in the inner shell (8); the extending end of the second slider (2) is hinged to the first slider (3) through the second connecting rod (12); the extending end is fixedly connected to the outer shell (10) through an elastic rod (9); the inner shell (8) is fixedly connected to the outer shell (10) through the elastic rod (9) at the other end of the second slider (2). The second connecting rod (12) is configured as a diamond connecting rod mechanism comprising four connecting rods hinged to each other. The lever rotation inertia unit comprises a first connecting rod (4) and a sector disk (5). The sector disk (5) is rotatably arranged in the inner shell (8). The other end of the first slider (3) hinged to the second slider (2) is hinged to the sector disk (5) through the first connecting rod (4). The eddy current super damping unit comprises magnets, and the sector disk (5) is arranged between the magnets.

2. The inertial-super damping coupling synergistic unit cell according to claim 1, characterized in that: The positive stiffness-negative stiffness unit also includes a connecting plate (1), the protruding end of the second slider (2) is fixedly connected to the connecting plate (1), and the connecting plate (1) is fixedly connected to the elastic rod (9) on the other side of the second slider (2).

3. The inertial-super damping coupling synergistic unit cell according to claim 1, characterized in that: The elastic rods (9) are provided in plurality, one of which is arranged on the central axis of the unit cell, and the others are symmetrically arranged on both sides of the central axis; The elastic rods (9) symmetrically arranged on both sides of the central axis are configured as elastic curved rods, and the distance between the connection end of the elastic curved rod close to the inner shell (8) and the central axis is smaller than the distance between the connection end with the outer shell (10) and the central axis.

4. The inertial-super damping coupling synergistic unit cell according to claim 1, characterized in that: The positive stiffness-negative stiffness unit also includes a preload spring (13). A support rod (15) is fixedly connected between the inner walls of the inner shell (8). The support rod (15) is sleeved with a preload spring (13). The two hinge points of the second connecting rod (12) that are not hinged to the slider are slidably sleeved on the support rod (15) through rings. The two hinge points of the second connecting rod (12) that are not hinged to the slider are connected through the preload spring (13).

5. The inertial-super damping coupling synergistic unit cell according to claim 1, characterized in that: A rotating shaft (14) is fixedly connected inside the inner shell (8), and the sector disk (5) is rotatably connected to the inner shell (8) via the rotating shaft (14); The hinge point between the first connecting rod (4) and the sector disk (5) is not coaxial with the rotation axis (14) of the sector disk (5).

6. The inertial-super damping coupling synergistic unit cell according to claim 1, characterized in that: The sector disks (5) are arranged in opposite directions, and the other end of the first slider (3) hinged to the second slider (2) is hinged to the two sector disks (5) respectively through two first connecting rods (4).

7. The inertial-super damping coupling synergistic unit cell according to claim 6, characterized in that: The eddy current super damping unit comprises a first magnet (6) and a second magnet (7), wherein two of the first magnet (6) and two of the second magnet (7) are arranged and mounted on the inner wall of the inner shell (8); In the height direction, the first magnet (6), the sector disk (5), the second magnet (7), the sector disk (5) and the first magnet (6) are arranged in sequence and spaced apart, and the two second magnets (7) are arranged in the same layer; The magnetic poles of the first magnet (6) and the second magnet (7) are opposite.

8. The inertial-super damping coupling synergistic unit cell according to claim 7, characterized in that: Two sector-shaped disks (5) are arranged in the same layer in the length direction, and two second magnets (7) are arranged on both sides of the sector-shaped disk (5); Two sector disks (5) are arranged in reverse symmetry on the same layer, and two second magnets (7) are arranged on both sides of the sector disk (5) without overlapping to form an initial state of a unit cell, and the length of the first magnet (6) is equal to the sum of the length of the chord corresponding to the central angle of the sector disk (5) and the length of the two second magnets (7).

9. The inertial-super damping coupling synergistic unit cell according to claim 1, characterized in that: The side walls of the inner shell (8) and the outer shell (10) are slidably connected via balls (11).

10. A local resonance metamaterial, characterized in that: The local resonance metamaterial comprises a plurality of unit cells according to any one of claims 1 to 9 connected in series or in parallel.

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