An electromagnet nonlinear variable stiffness unit cell and metamaterial vibration isolation support

Abstract

The present invention relates to an electromagnet nonlinear variable stiffness unit cell and a metamaterial vibration isolation support, comprising an electromagnet-spring-electromagnet variable stiffness unit, an auxiliary stiffness adjustment component, and a stiffness adjustment and eddy current damping energy dissipation component. The electromagnet-spring-electromagnet variable stiffness unit comprises a first electromagnet, a second electromagnet, and a preload spring, the first and second electromagnets being connected by the preload spring. The auxiliary stiffness adjustment component comprises a magnetic support and a hollow sleeve, the electromagnet being connected to the magnetic support via a spring. The stiffness adjustment and eddy current damping energy dissipation component comprises a current-carrying plate and a magnetic-carrying plate, the current-carrying plate and the magnetic-carrying plate being spaced apart on the hollow sleeve, and the electromagnet-spring-electromagnet variable stiffness unit being suspended through the hollow sleeve. Compared with the prior art, the present invention realizes time-varying, controllable, and adjustable stiffness within the local resonance unit of the metamaterial unit cell, achieving adaptive bandgap adjustment based on displacement amplitude and enhanced vibration reduction effects.

Description

Technical Field

[0001] The invention belongs to the technical field of civil engineering and relates to an electromagnet nonlinear variable stiffness unit cell and a metamaterial vibration isolation support. 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. Traditional local resonance metamaterials set local resonance units wrapped by flexible materials in the unit cell structure, thereby generating a band gap that prevents the propagation of elastic waves, which provides the possibility of achieving low-frequency band gaps and constructing metamaterials in the field of earthquake engineering. However, local resonance metamaterials are insufficient to effectively attenuate elastic waves (equivalent damping) within the resonance band gap. To achieve low-frequency and broadband band gaps, it is often necessary to increase the additional mass of the resonance unit and reduce the stiffness within the resonance unit. The metamaterial unit cell and structural form do not have the adaptive time-varying adjustment of the metamaterial mechanical parameters, which limits the application of such technologies in complex engineering and intelligent manufacturing (construction) engineering.

[0003] Patent CN115789164A discloses an adjustable stiffness low-frequency vibration isolation device with rubber and electromagnetic parallel connection, including an upper support platform, a rubber support structure, a base, a central axis and a vibration isolator. The vibration isolator is a linear magnetic negative stiffness low-frequency vibration isolator including a vibration isolation box, two spring positive stiffness modules installed in the vibration isolation box, and an electromagnetic negative stiffness module. The electromagnetic negative stiffness module includes an upper annular permanent magnet, a middle annular permanent magnet and a lower annular permanent magnet arranged axially along the central axis, and an annular coil configured for each permanent magnet. This patent adjusts the negative stiffness of the electromagnetic negative stiffness module by adjusting the compression of the spring positive stiffness unit, thereby ensuring that the system has both high load-bearing capacity and low-frequency vibration isolation performance, but the electromagnetic negative stiffness module of this patent can only provide negative stiffness for the vibration isolation device; at the same time, although linear negative stiffness is provided by coupling the attractive electromagnetic negative stiffness structure and the repulsive electromagnetic negative stiffness mechanism, it cannot provide nonlinear enhanced negative stiffness coordinated with displacement and time-varying adjustable and controllable positive stiffness-quasi-zero stiffness-negative stiffness.

[0004] Patent CN206234312U discloses a magnetic quasi-zero stiffness isolator with adjustable stiffness, in which an elastic capsule providing positive stiffness is connected in parallel with three transversely magnetized rectangular magnetic blocks providing negative stiffness. When the isolation mass changes, the elastic capsule's working position is controlled to remain unchanged, and the elastic capsule's positive stiffness changes due to changes in internal pressure. At the same time, the position of the magnets is adjusted laterally to match the current positive stiffness. However, this patent still uses a traditional attractive three-magnet negative stiffness structure, resulting in it only being able to achieve a negative stiffness effect and lacking the time-varying controllable and adjustable capabilities of positive stiffness, quasi-zero stiffness, and negative stiffness. In addition, the traditional structure has defects such as complexity and low adjustment accuracy, making it difficult to expand into a metamaterial unit cell design configuration.

[0005] Patent CN112460177A discloses a quasi-zero-stiffness isolator with adaptive negative stiffness adjustment. A motor simultaneously drives a coupling to rotate a screw. The screw slider adjusts the negative stiffness adjustment spring according to the forward and reverse rotation of the motor. Adjusting the effect of two flexible links on the intermediate connector achieves negative stiffness adjustment based on changes in load mass. However, this patent relies entirely on mechanical structures to adjust negative stiffness, resulting in complex structure and poor sensitivity. The motor and mechanical structure make it difficult to control the volume of the structure, resulting in low reliability of unit cell stacking and inability to expand to metamaterial unit cell design configurations.

[0006] Patent CN215334137U discloses an electromagnetic damping magnetorheological vibration absorber, comprising: a cylindrical shell, an outer magnet yoke, an inner magnet yoke of a mass coil group, a central axis, a spring, and a spring; the inner magnet yoke is directly clamped on the central axis, the mass group contains a damping channel, which is located on the central axis and outside the inner magnet yoke, forming an internal loop, a coil is wound around the mass, and the outer magnet yoke is located outside the coil. Although this patent achieves energy dissipation by cutting the magnetic field through the mass block and achieves mass adjustment through magnetorheological fluid, the displacement of the mass block is consistent with the external displacement (i.e., it does not have additional internal vibration degrees of freedom), which limits its effect of amplifying the deformation of the nonlinear damping element under small deformation conditions; it does not have the time-varying controllable and adjustable capabilities of positive stiffness, quasi-zero stiffness, and negative stiffness, and cannot achieve an adaptive vibration reduction effect based on displacement amplitude.

[0007] Patent CN116336119A discloses an electromagnetic variable stiffness and damping vibration isolator, comprising a load platform, an isolation element, a coil wound around a cylinder, a permanent magnet, a base, and a variable stiffness and damping control unit. The isolation element is mounted on the base to support the load platform, the cylinder is fixed to the bottom of the load platform, and the permanent magnet is mounted on the base and positioned around the coil. The variable stiffness and damping control unit comprises a main control board, a current control module, and a vibration sensor. The vibration sensor is fixed to the load platform, and the main control board is electrically connected to the vibration sensor and the current control module. Although the device in this patent achieves equipment vibration control by introducing an electromagnetic variable stiffness and damping device, the displacement of the load platform and the isolator are consistent (i.e., there is no additional internal vibration degree of freedom). This device cannot provide a local resonance mechanism within the isolator, cannot achieve deformation amplification of the nonlinear damping element under small deformation vibration scenarios, and lacks the ability to form a metamaterial isolation layer to establish a broadband low-frequency bandgap.

[0008] Patent CN114087308A discloses an electromagnetic non-smooth vibration absorber, comprising: a first electromagnet, a second electromagnet, a mass block, a sleeve, an electromagnet power supply module, a guide rail, a connecting rod, a tension spring and an outer frame, wherein the first electromagnet is installed in the sleeve, and the upper bottom surface and the lower bottom surface of the mass block are respectively connected to a second electromagnet through a connecting rod; a tension spring is installed between the left side of the mass block and the left inner wall of the outer frame, and a tension spring is installed between the right side of the mass block and the right inner wall of the outer frame; the top of the guide rail is connected to the top inner wall of the outer frame, and the bottom of the guide rail is connected to the bottom inner wall of the outer frame; the second electromagnet connected to the upper bottom surface of the mass block is connected to the polarity of the first electromagnet installed on the top of the outer frame and is attracted; the second electromagnet connected to the lower bottom surface of the mass block is connected to the polarity of the first electromagnet installed on the bottom of the outer frame and is attracted. Although the device of this patent achieves the effect of nonlinear vibration absorption by using a proximity switch-solid-state relay, the design can only achieve a non-smooth single variable stiffness point, and cannot achieve the adjustable and controllable deformation position of the variable stiffness point. It has not yet involved the time-varying mechanism of positive stiffness-quasi-zero stiffness-negative stiffness, and cannot expand the metamaterial unit cell configuration with variable stiffness and electromagnetic damping enhancement. Summary of the Invention

[0009] The purpose of the present invention is to provide an electromagnet nonlinear variable stiffness unit cell and a metamaterial vibration isolation support in order to overcome at least one of the defects of the above-mentioned prior art. The present invention realizes the time-varying controllable and adjustable stiffness of the local resonance unit in the metamaterial unit cell, and realizes adaptive band gap adjustment and vibration reduction enhancement effect based on displacement amplitude.

[0010] The purpose of the present invention can be achieved by the following technical solutions:

[0011] One of the technical solutions of the present invention is to provide an electromagnet nonlinear variable stiffness unit cell, which includes an electromagnet-spring-electromagnet variable stiffness unit, an auxiliary stiffness adjustment component, a stiffness adjustment and eddy current damping energy dissipation component,

[0012] The electromagnet-spring-electromagnet variable stiffness unit includes a first electromagnet, a second electromagnet and a preload spring, wherein the first electromagnet and the second electromagnet are connected via the preload spring.

[0013] The auxiliary stiffness adjustment component includes a magnetic support and a hollow sleeve, and the electromagnet is connected to the magnetic support through a spring.

[0014] The stiffness adjustment and eddy current damping energy dissipation component includes a current conducting plate and a magnetic conducting plate, the current conducting plate and the magnetic conducting plate are arranged on the hollow sleeve at intervals, and the electromagnet-spring-electromagnet variable stiffness unit is suspended through the hollow sleeve;

[0015] When the electromagnet-spring-electromagnet variable stiffness unit moves horizontally relative to the hollow sleeve, the two electromagnets begin to cut the magnetic flux lines generated by the double-pass conductive plate, thereby generating an induced electromotive force inside the electromagnet and increasing, decreasing, or even changing the magnetism of the electromagnet. The attractive or repulsive force between the electromagnet-spring-electromagnet variable stiffness unit and the left and right magnetic supports changes continuously with the vibration of the electromagnet-spring-electromagnet variable stiffness unit, forming variable stiffness.

[0016] A preload spring between the two electromagnets is connected in series with the electromagnets, and the force of the preload spring increases the relative deformation between the two electromagnets, that is, increases the deformation of the negative stiffness;

[0017] In addition, the double-pass magnetic conductivity plate on the hollow sleeve and the electromagnet-spring-electromagnet variable stiffness unit also form an eddy current damping energy dissipation mechanism. The movement of the electromagnet cuts the magnetic lines of force to generate an eddy current field. The Lorentz force generated by the interaction between the eddy current and the magnetic field will hinder the relative movement between the electromagnet and the magnetic field. At the same time, the eddy current will be converted into heat energy dissipation in the electromagnet, further increasing the stability and damping energy dissipation of the horizontal relative movement of the electromagnet-spring-electromagnet variable stiffness unit.

[0018] As an optimal technical solution, the direction, magnitude and frequency of the current in the energized conductive plate on the hollow sleeve are controlled so that the unit cell can achieve flexible changes in positive stiffness, negative stiffness and quasi-zero stiffness. By changing the current in the energized conductive plate, the stiffness characteristics between the electromagnets are changed, further affecting the seismic isolation efficiency and damping.

[0019] Furthermore, the electromagnet-spring-electromagnet variable stiffness unit includes a first electromagnet, a second electromagnet, a first pre-stressed spring and a second pre-stressed spring, and the inner ends of the first electromagnet and the second electromagnet are connected by the first pre-stressed spring and the second pre-stressed spring to form an electromagnet-spring-electromagnet variable stiffness unit, and the first pre-stressed spring and the second pre-stressed spring are connected in parallel.

[0020] Furthermore, the first electromagnet and the second electromagnet are both connected to the magnetic support via an oblique spring and a horizontal spring, and the oblique spring and the horizontal spring are connected in parallel;

[0021] The oblique spring and horizontal spring connecting the electromagnet and the magnetic support are connected in parallel, and at the same time are connected in series with the electromagnet-spring-electromagnet variable stiffness unit. While limiting the vertical displacement of the electromagnet-spring-electromagnet variable stiffness unit from being too large, the diversity of the stiffness adjustment mechanism is increased.

[0022] Furthermore, the auxiliary stiffness adjustment member includes a first magnetic support, a second magnetic support and a hollow sleeve.

[0023] The outer end of the first electromagnet is connected to the first magnetic support through a first oblique spring, a first horizontal spring, and a second oblique spring. The first oblique spring, the first horizontal spring, and the second oblique spring are connected in parallel. The first oblique spring and the second oblique spring are symmetrically arranged with respect to the first horizontal spring.

[0024] The outer end of the second electromagnet is connected to the second magnetic support through a third oblique spring, a second horizontal spring and a fourth oblique spring. The third oblique spring, the second horizontal spring and the fourth oblique spring are connected in parallel. The third oblique spring and the fourth oblique spring are arranged symmetrically about the second horizontal spring.

[0025] Furthermore, limiting slide rails are provided on both sides of the hollow sleeve, and both ends of the limiting slide rails are connected to the magnetic supports through connecting springs, so that the hollow sleeve moves relative to the electromagnet-spring-electromagnet variable stiffness unit along the direction of the limiting slide rails.

[0026] Furthermore, a first limiting slide rail and a second limiting slide rail are fixedly connected to opposite sides of the hollow sleeve.

[0027] One end of the first limiting slide rail is connected to the first magnetic support via a first connecting spring, and the other end is connected to the second magnetic support via a second connecting spring.

[0028] One end of the second limiting slide rail is connected to the first magnetic support through a third connecting spring, and the other end is connected to the second magnetic support through a fourth connecting spring.

[0029] Furthermore, the magnetic poles of the first magnetic support, the original magnetic poles of the first electromagnet, the original magnetic poles of the second electromagnet and the magnetic poles of the second magnetic support are opposite to each other, that is, the unit cell is initially a negative stiffness system.

[0030] Furthermore, the stiffness adjustment and eddy current damping energy-absorbing component includes a first current-carrying conductive plate, a second current-carrying conductive plate, a first magnetic conductive plate and a second magnetic conductive plate. The two side surfaces of the hollow sleeve are fixedly connected with the first current-carrying conductive plate and the second current-carrying conductive plate, and the other adjacent two side surfaces are fixedly connected with the first magnetic conductive plate and the second magnetic conductive plate.

[0031] As an optimal technical solution, the diameter of the hollow sleeve is slightly larger than the height and width of the electromagnet, so that the electromagnet-spring-electromagnet variable stiffness unit is located in the hollow sleeve without contacting or squeezing the hollow sleeve from above, below, left and right.

[0032] As a preferred technical solution, by adjusting the direction, magnitude and frequency of the current in the energized conductive plate, the magnetic field in the two energized conductive plates is adjusted, so that the unit cell exhibits enhanced negative stiffness, suppressed negative stiffness or quasi-zero stiffness. In addition, the magnetic field strength will affect the ability of eddy currents to damp energy consumption, thereby affecting the damping ratio of the unit cell.

[0033] One of the technical solutions of the present invention is to provide a method for nonlinearly varying the stiffness of an electromagnet, wherein the method adopts the unit cell to vary the stiffness, and comprises the following steps:

[0034] When the unit cell is working, the first electromagnet and the second electromagnet form an electromagnet-spring-electromagnet variable stiffness unit through the preload spring and a hollow sleeve with an additional current conducting plate and a magnetic conducting plate to undergo relative horizontal displacement;

[0035] The energized conductive plate generates a magnetic field inside the hollow sleeve, and the relative horizontal movement of the electromagnet-spring-electromagnet variable stiffness unit cuts the magnetic flux lines. The first electromagnet and the second electromagnet inside the electromagnet-spring-electromagnet variable stiffness unit generate an induced electromotive force, which in turn generates an induced current, thereby changing the magnetic properties of the first electromagnet and the second electromagnet.

[0036] S1. After the conductive plate is energized to generate an induced magnetic field, if the electromotive force generated by the movement of the electromagnet-spring-electromagnet variable stiffness unit causes the first electromagnet and the second electromagnet to generate a magnetic field dominated by the original magnetic pole, then the magnetism of the first electromagnet and the second electromagnet will be greater than when the power is not supplied, and the unit cell will exhibit synergistic negative stiffness.

[0037] S2. After the conductive plate is energized to generate an induced magnetic field, if the electromotive force generated by the movement of the electromagnet-spring-electromagnet variable stiffness unit causes the first electromagnet and the second electromagnet to generate magnetic fields with partially opposite original magnetic poles, and the generated induced magnetic field does not exceed the magnetic fields of the first electromagnet and the second electromagnet themselves, then the magnetism of the first electromagnet and the second electromagnet is smaller than when no power is applied, and the unit cell exhibits suppressed negative stiffness;

[0038] S3. After the conductive plate is energized to generate an induced magnetic field, if the electromotive force generated by the movement of the electromagnet-spring-electromagnet variable stiffness unit causes the first electromagnet and the second electromagnet to generate magnetic fields with partially opposite original magnetic poles, and the generated induced magnetic field just reaches the magnetic fields of the first electromagnet and the second electromagnet themselves, the magnetism of the first electromagnet and the second electromagnet will temporarily disappear, and the unit cell will exhibit quasi-zero stiffness.

[0039] S4. After the conductive plate is energized to generate an induced magnetic field, if the electromotive force generated by the movement of the electromagnet-spring-electromagnet variable stiffness unit causes the first electromagnet and the second electromagnet to generate magnetic fields dominated by opposite original magnetic poles, and the generated induced magnetic field exceeds the magnetic fields of the first electromagnet and the second electromagnet themselves, the magnetism of the first electromagnet and the second electromagnet will temporarily change, and the unit cell will exhibit positive stiffness.

[0040] One of the technical solutions of the present invention is to provide a metamaterial vibration isolation support, which includes a vibration reduction module and end plates. In the length direction, multiple end plates are connected in series through the vibration reduction module, and the vibration reduction module includes a plurality of parallel arrays of unit cells.

[0041] The end plate includes a first support plate, a second support plate and a damping coating. The two support plates have sufficient rigidity. A damping coating is coated between the first support plate and the second support plate. The damping coating has a certain sliding property. The presence of the damping coating enables the support to have vibration isolation and energy dissipation capabilities in the horizontal direction.

[0042] When each unit cell in the vibration reduction module is externally excited, the first electromagnet and the second electromagnet in a single unit cell start to move, and three stiffness change states can be generated according to the size, direction and frequency of the current passed through the energized conductive plate;

[0043] When external excitation persists, the nonlinear strength, negative stiffness ratio, damping ratio and other parameters of the unit cell are adjusted according to different structures, so that all the unit cells of a single vibration reduction module can jointly form a local resonance type electromagnetic nonlinear variable stiffness oscillator element, broaden the frequency band range of the vibration attenuation zone (bandgap), and reduce the center frequency of the bandgap, so that the frequency of the vibration attenuation zone is reduced to a frequency close to that of the low-frequency band of seismic waves. Based on the electromagnetic damping energy dissipation and low-frequency bandgap mechanism, the propagation of seismic waves is effectively suppressed and the peak value is rapidly attenuated, thereby obtaining a low-bandwidth vibration isolation effect.

[0044] As a preferred technical solution, by changing the direction of the unit cells in each vibration isolation module, such as making all the unit cell directions in the odd-layer vibration isolation module (the unit cell axis is parallel to the x-axis) and all the unit cell directions in the even-layer vibration isolation module (the unit cell axis is parallel to the y-axis) orthogonal, or making the unit cell directions in each layer of vibration isolation module different, or making the directions of each unit cell in a single-layer vibration isolation module different, multi-directional synergistic bandgap broadening and damping can be achieved, thereby realizing multi-dimensional metamaterial synergistic vibration isolation that is different from the traditional vibration isolation support technology route.

[0045] As a preferred technical solution, the single layer of the support includes two end plates and a vibration damping module, and the first magnetic support and the second magnetic support of the unit cell are fixedly connected to the first support plate and the second support plate belonging to the two end plates respectively.

[0046] Furthermore, in the length direction, the multiple end plates are connected in series via support springs, and the multiple unit cells and support springs are arrayed in parallel.

[0047] As a preferred technical solution, both ends of the support spring are fixedly connected to a first support plate and a second support plate belonging to two end plates respectively.

[0048] As a preferred technical solution, in the width direction, the unit cells and the supporting springs are arranged in an array with intervals, and in the thickness direction, the unit cells and the supporting springs are arranged in an equidistant array, so as to form a multi-component stiffness adjustment mechanism in which the unit cells and the springs are connected in parallel.

[0049] One of the technical solutions of the present invention is to provide a metamaterial vibration isolation method, which uses the support to perform vibration isolation, including the following steps:

[0050] When external excitation occurs, multiple unit cells within the vibration isolation module begin to vibrate. Due to the different relative positions of the unit cells within the module, the vibrations generated by the external excitation are different. The dynamic characteristics and stiffness change amplitudes of each unit cell are also different. The vibrations of each unit cell affect each other, forming a good low-frequency elastic wave band gap and wave guiding characteristics to isolate the low-frequency vibrations generated by the earthquake.

[0051] In the longitudinal direction, the vibration reduction modules at different positions are also controlled by external excitation. The stiffness and frequency of each vibration reduction module are different. At the same time, due to the slidability of the end plates, the stiffness and frequency of adjacent vibration reduction modules affect each other, further realizing the control of low-frequency waves and suppressing large deformation while achieving negative stiffness.

[0052] Compared with the prior art, the present invention has the following beneficial effects:

[0053] (1) In the proposed unit cell, the present invention utilizes an electromagnet-spring-electromagnet variable stiffness unit to realize the controllable and adjustable time-varying stiffness based on the electromagnetic time-varying mechanism. In a conventional vibration isolation system, the nonlinear stiffness generated by the system component unit usually has only one direction, namely, positive stiffness, negative stiffness or quasi-zero stiffness. The present invention can effectively change the magnitude of the magnetic force at both ends of the electromagnet-spring-electromagnet variable stiffness unit or change the magnetism by controlling the magnitude, direction and frequency of the current in the energized conductive plate attached to the hollow sleeve. It can even generate alternating magnetism by introducing an alternating current as required, thereby forming a positive stiffness, negative stiffness and quasi-zero stiffness system with adjustable vibration isolation efficiency and damping together with a magnetic support with constant magnetism.

[0054] (2) The present invention utilizes the property that spring stiffness is easy to adjust, and sets a preload spring between the electromagnets to form an electromagnet-spring-electromagnet variable stiffness unit; the preload spring set can promote the vibration of the electromagnet-spring-electromagnet variable stiffness unit when horizontal relative motion occurs, accelerate the rate of effective cutting of magnetic flux lines, and increase the sensitivity of the vibration isolation system to small relative displacements while shortening the time for effective stiffness formation; the two electromagnets are connected in series, and a negative stiffness unit is added inside the electromagnet-spring-electromagnet variable stiffness unit to increase the diversity of the stiffness adjustment mechanism; the two ends of the electromagnet-spring-electromagnet variable stiffness unit are connected to the magnetic support with a spring, and the variable stiffness is connected in series with the parallel spring stiffness, thereby increasing the diversity of the stiffness adjustment mechanism and ensuring that the unit cell has a certain energy dissipation and vibration reduction effect when it is not powered;

[0055] (3) The present invention utilizes the characteristics of adaptive adjustment of eddy current damping to allow the unit cell to provide considerable adaptive energy consumption according to the characteristics of the movement of the electromagnet-spring-electromagnet variable stiffness unit, while reducing the influence of the self-vibration of the electromagnet-spring-electromagnet variable stiffness unit on the vibration isolation structure;

[0056] (4) The present invention realizes a nonlinear variable stiffness unit based on an electromagnet-spring-electromagnet; provides a nonlinear damping unit in the form of a magnetic conductive plate-electromagnet; realizes nonlinear multi-component stiffness adjustment by combining electromagnet-spring-magnetic support in series and parallel, and realizes adaptive band gap adjustment and vibration reduction enhancement effect based on displacement amplitude, which is conducive to realizing adaptive metamaterial-type enhanced vibration isolation of engineering and mechanical structures under multi-level and multi-source excitation;

[0057] (5) In the vibration isolation support proposed by the present invention, based on the different dynamic characteristics and stiffness change amplitudes of the unit cells at different positions under external excitation, the frequency and stiffness characteristics of each vibration reduction module under the different influences of the dynamic characteristics and stiffness of the internal unit cells are different, and the vibrations of each unit cell affect each other, and the movements between adjacent vibration reduction modules also affect each other, forming a good low-frequency broadened elastic wave band gap, electromagnetic damping energy dissipation and wave guiding characteristics to isolate the low-frequency vibration generated by the earthquake and suppress the vibration peak, thereby realizing multi-dimensional adaptive metamaterial-type enhanced vibration isolation while avoiding the need for large deformation vibration isolation belts concentrated in traditional flexible vibration isolation layers. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 Schematic diagram of the front view structure of the electromagnet nonlinear variable stiffness unit cell in an embodiment of the present invention;

[0059] Figure 2 Schematic diagram of the front perspective structure of the electromagnet nonlinear variable stiffness unit cell according to an embodiment of the present invention;

[0060] Figure 31-1 is a schematic cross-sectional structure diagram of an electromagnet nonlinear variable stiffness unit cell according to an embodiment of the present invention;

[0061] Figure 4 Schematic diagram of the detailed structure of the end plate in front view according to an embodiment of the present invention;

[0062] Figure 5 Schematic diagram of the side view structure of a single layer of a metamaterial vibration isolation support in an embodiment of the present invention;

[0063] Figure 6 Schematic diagram of the three-dimensional structure of the two layers of the metamaterial vibration isolation support in an embodiment of the present invention.

[0064] Description of the marks in the figure:

[0065] 1—first magnetic support, 2—second magnetic support, 3—first limiting slide rail, 4—second limiting slide rail, 5—first electromagnet, 6—second electromagnet, 7—first current-carrying guide plate, 8—second current-carrying guide plate, 9—first magnetic guide plate, 10—second magnetic guide plate, 11—first oblique spring, 12—first horizontal spring, 13—second oblique spring, 14—first preload spring, 15—second preload spring, 16—third oblique spring, 17—second horizontal spring, 18—fourth oblique spring, 19—hollow sleeve, 20—first connecting spring, 21—second connecting spring, 22—third connecting spring, 23—fourth connecting spring, 24—first support plate, 25—second support plate, 26—damping coating, 27—support spring. DETAILED DESCRIPTION

[0066] The present invention is described in detail below with reference to specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0067] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended only to facilitate the description of the present invention and simplify the description. They are not intended to indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," and the like, used to describe common objects, merely refer to different instances of the same object and are not intended to imply that the objects described must be in a given order, whether temporally, spatially, sequentially, or in any other manner.

[0068] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0069] Example:

[0070] An electromagnet nonlinear variable stiffness unit cell, such as Figures 1 to 3 As shown, it includes an electromagnet-spring-electromagnet variable stiffness unit, an auxiliary stiffness adjustment component, a stiffness adjustment and eddy current damping energy dissipation component,

[0071] The electromagnet-spring-electromagnet variable stiffness unit includes a first electromagnet 5, a second electromagnet 6 and a preload spring. The first electromagnet 5 and the second electromagnet 6 are connected by the preload spring.

[0072] The auxiliary stiffness adjustment component includes a magnetic support and a hollow sleeve 19. The electromagnet is connected to the magnetic support through a spring.

[0073] The stiffness adjustment and eddy current damping energy dissipation components include a current conducting plate and a magnetic conducting plate. The current conducting plate and the magnetic conducting plate are arranged at intervals on the hollow sleeve 19. The electromagnet-spring-electromagnet variable stiffness unit is suspended through the hollow sleeve 19.

[0074] By controlling the direction, magnitude and frequency of the current in the conductive plate on the hollow sleeve 19, the unit cell can achieve flexible changes in positive stiffness, negative stiffness and quasi-zero stiffness. By changing the current in the conductive plate, the stiffness characteristics between the electromagnets are changed, further affecting the seismic isolation efficiency and damping.

[0075] When the electromagnet-spring-electromagnet variable stiffness unit moves horizontally relative to the hollow sleeve 19, the two electromagnets begin to cut the magnetic flux lines generated by the double-pass conductive plate, thereby generating an induced electromotive force inside the electromagnet, which can simultaneously increase, decrease, or even change the magnetism of the electromagnet. The attractive or repulsive force between the electromagnet-spring-electromagnet variable stiffness unit and the left and right magnetic supports continuously changes with the vibration of the electromagnet-spring-electromagnet variable stiffness unit, forming a variable stiffness.

[0076] The preload spring between the two electromagnets is connected in series with the electromagnets. The force of the preload spring can increase the relative deformation between the two electromagnets, that is, increase the deformation of the negative stiffness.

[0077] In addition, the dual-pass magnetic permeability plate on the hollow sleeve 19 and the electromagnet-spring-electromagnet variable stiffness unit can also form an eddy current damping energy dissipation mechanism. The movement of the electromagnet cuts the magnetic flux lines to generate an eddy current field. The Lorentz force generated by the interaction between the eddy current and the magnetic field will hinder the relative motion between the electromagnet and the magnetic field. At the same time, the eddy current will be converted into heat energy dissipation in the electromagnet, further increasing the stability and damping energy dissipation of the horizontal relative motion of the electromagnet-spring-electromagnet variable stiffness unit.

[0078] The electromagnet-spring-electromagnet variable stiffness unit includes a first electromagnet 5, a second electromagnet 6, a first pre-compression spring 14, and a second pre-compression spring 15. The inner ends of the first electromagnet 5 and the second electromagnet 6 are connected by the first pre-compression spring 14 and the second pre-compression spring 15 to form an electromagnet-spring-electromagnet variable stiffness unit. The first pre-compression spring 14 and the second pre-compression spring 15 are connected in parallel.

[0079] The first electromagnet 5 and the second electromagnet 6 are both connected to the magnetic support via an oblique spring and a horizontal spring, and the oblique spring and the horizontal spring are connected in parallel;

[0080] The oblique spring and horizontal spring connecting the electromagnet and the magnetic support are connected in parallel and in series with the electromagnet-spring-electromagnet variable stiffness unit. This not only limits the vertical displacement of the electromagnet-spring-electromagnet variable stiffness unit from being too large, but also increases the diversity of the stiffness adjustment mechanism.

[0081] The auxiliary stiffness adjustment component includes a first magnetic support 1, a second magnetic support 2 and a hollow sleeve 19.

[0082] The outer end of the first electromagnet 5 is connected to the first magnetic support 1 through the first oblique spring 11, the first horizontal spring 12 and the second oblique spring 13. The first oblique spring 11, the first horizontal spring 12 and the second oblique spring 13 are connected in parallel. The first oblique spring 11 and the second oblique spring 13 are symmetrically arranged with respect to the first horizontal spring 12.

[0083] The outer end of the second electromagnet 6 is connected to the second magnetic support 2 through a third oblique spring 16, a second horizontal spring 17 and a fourth oblique spring 18. The third oblique spring 16, the second horizontal spring 17 and the fourth oblique spring 18 are connected in parallel. The third oblique spring 16 and the fourth oblique spring 18 are symmetrically arranged about the second horizontal spring 17.

[0084] Limiting rails are provided on both sides of the hollow sleeve 19. The two ends of the limiting rails are connected to the magnetic supports through connecting springs, so that the hollow sleeve 19 can move relative to the electromagnet-spring-electromagnet variable stiffness unit along the direction of the limiting rails.

[0085] The first limiting slide rail 3 and the second limiting slide rail 4 are fixedly connected to opposite sides of the hollow sleeve 19.

[0086] One end of the first limiting slide rail 3 is connected to the first magnetic support 1 through the first connecting spring 20, and the other end is connected to the second magnetic support 2 through the second connecting spring 21.

[0087] One end of the second limiting slide rail 4 is connected to the first magnetic support 1 through the third connecting spring 22, and the other end is connected to the second magnetic support 2 through the fourth connecting spring 23;

[0088] The magnetic pole of the first magnetic support 1 is selected as N (S) pole, and the magnetic pole of the second magnetic support 2 is selected as S (N) pole;

[0089] The original magnetic pole of the first electromagnet 5 is selected as the S (N) pole, and the original magnetic pole of the second electromagnet 6 is selected as the N (S) pole, that is, the unit cell is initially a negative stiffness system;

[0090] The stiffness adjustment and eddy current damping energy dissipation component includes a first current conducting plate 7, a second current conducting plate 8, a first magnetic conducting plate 9, and a second magnetic conducting plate 10. The two sides of the hollow sleeve 19 are fixedly connected to the first current conducting plate 7 and the second current conducting plate 8, and the other adjacent two sides are fixedly connected to the first magnetic conducting plate 9 and the second magnetic conducting plate 10.

[0091] The first current conducting plate 7 and the second current conducting plate 8 have different magnetic properties, thereby forming a vertical downward magnetic field, and a horizontal rightward magnetic field between the first magnetic flux conducting plate 9 and the second magnetic flux conducting plate 10;

[0092] The diameter of the hollow sleeve 19 is slightly larger than the height and width of the electromagnet, so that the electromagnet-spring-electromagnet variable stiffness unit is located in the hollow sleeve 19 without contacting or squeezing the hollow sleeve 19 from above, below, left, and right.

[0093] By adjusting the direction, magnitude, and frequency of the current in the energized conductive plate, the magnetic field in the two energized conductive plates is adjusted, so that the unit cell exhibits enhanced negative stiffness, suppressed negative stiffness, or quasi-zero stiffness. In addition, the magnetic field strength will affect the ability of eddy currents to damp energy dissipation, thereby affecting the damping ratio of the unit cell.

[0094] In this embodiment, the material of the magnetic support and the magnetic conductive plate is steel magnetic plate, the material of the limiting slide rail and the hollow sleeve 19 is steel, the material of the electromagnet and the spring (oblique spring, horizontal spring, pre-stressed spring and connecting spring) is carbon steel, and the material of the current conductive plate is copper plate.

[0095] A nonlinear stiffness variable method for an electromagnet uses the above-mentioned unit cell to vary stiffness, and the specific steps are as follows:

[0096] When the unit cell is working, the first electromagnet 5 and the second electromagnet 6 are horizontally displaced relative to the hollow sleeve 19 to which the first and second current conducting plates 7 and 8 and the first and second magnetic conducting plates 9 and 10 are attached, by means of the electromagnet-spring-electromagnet variable stiffness unit formed by the first pre-compression spring 14 and the second pre-compression spring 15.

[0097] The first and second conductive plates 7 and 8 generate a magnetic field inside the hollow sleeve 19. The relative horizontal movement of the electromagnet-spring-electromagnet variable stiffness unit cuts the magnetic flux lines, and the first and second electromagnets 5 and 6 inside the electromagnet-spring-electromagnet variable stiffness unit generate an induced electromotive force, which in turn generates an induced current, thereby changing the magnetic properties of the first and second electromagnets 5 and 6.

[0098] S1. After the conductive plate is energized to generate an induced magnetic field, if the electromotive force generated by the movement of the electromagnet-spring-electromagnet variable stiffness unit causes the first electromagnet 5 to generate a magnetic field dominated by the S pole and the second electromagnet 6 to generate a magnetic field dominated by the N pole, then the magnetism of the first electromagnet 5 and the second electromagnet 6 will be greater than when no power is applied, and the unit cell will exhibit synergistic negative stiffness.

[0099] S2. After the conductive plate is energized to generate an induced magnetic field, if the electromotive force generated by the movement of the electromagnet-spring-electromagnet variable stiffness unit causes the first electromagnet 5 to generate a partial N-pole magnetic field and the second electromagnet 6 to generate a partial S-pole magnetic field, and the generated induced magnetic field does not exceed the magnetic fields of the first electromagnet 5 and the second electromagnet 6, then the magnetism of the first electromagnet 5 and the second electromagnet 6 is smaller than when no power is applied, and the unit cell exhibits suppressed negative stiffness;

[0100] S3. After the conductive plate is energized to generate an induced magnetic field, if the electromotive force generated by the movement of the electromagnet-spring-electromagnet variable stiffness unit causes the first electromagnet 5 to generate a partial N-pole magnetic field and the second electromagnet 6 to generate a partial S-pole magnetic field, and the generated induced magnetic field just reaches the magnetic fields of the first electromagnet 5 and the second electromagnet 6, then the magnetism of the first electromagnet 5 and the second electromagnet 6 temporarily disappears, and the unit cell exhibits quasi-zero stiffness.

[0101] S4. After the conductive plate is energized to generate an induced magnetic field, if the electromotive force generated by the movement of the electromagnet-spring-electromagnet variable stiffness unit causes the first electromagnet 5 to generate a magnetic field dominated by the N pole and the second electromagnet 6 to generate a magnetic field dominated by the S pole, and the generated induced magnetic field exceeds the magnetic fields of the first electromagnet 5 and the second electromagnet 6 themselves, then the magnetism of the first electromagnet 5 and the second electromagnet 6 will temporarily change, and at this time the unit cell will exhibit positive stiffness.

[0102] A metamaterial vibration isolation support, such as Figures 4 to 6As shown, it includes n vibration reduction modules and n+1 end plates. In the length direction, the multiple end plates are connected in series through the vibration reduction modules. The vibration reduction modules include multiple parallel arrays of the above-mentioned unit cells.

[0103] The end plate includes a first support plate 24, a second support plate 25 and a damping coating 26. The two support plates have sufficient rigidity. A damping coating 26 is coated between the first support plate 24 and the second support plate 25. The damping coating has a certain degree of sliding properties. The presence of the damping coating enables the support to have vibration isolation and energy dissipation capabilities in the horizontal direction.

[0104] When each unit cell in the vibration reduction module is stimulated by external force, the first electromagnet 5 and the second electromagnet 6 in a single unit cell start to move, and three stiffness change states can be generated according to the size, direction and frequency of the current flowing through the energized conductive plate;

[0105] When external excitation persists, the nonlinear strength, negative stiffness ratio, damping ratio and other parameters of the unit cell are adjusted according to different structures. All the unit cells of a single vibration reduction module can form a local resonance type electromagnetic nonlinear variable stiffness oscillator element, broaden the frequency band of the vibration attenuation zone (bandgap), and reduce the center frequency of the bandgap, so that the frequency of the vibration attenuation zone is reduced to a frequency close to the low-frequency band of the seismic wave. Based on the electromagnetic damping energy dissipation and low-frequency bandgap mechanism, the propagation of seismic waves is effectively suppressed and the peak value is rapidly attenuated, thereby obtaining a low-bandwidth vibration isolation effect.

[0106] By changing the orientation of the unit cells in each vibration isolation module, for example, making all unit cell directions in an odd-layer vibration isolation module (the unit cell axis is parallel to the x-axis) orthogonal to all unit cell directions in an even-layer vibration isolation module (the unit cell axis is parallel to the y-axis), or making the unit cell directions in each layer of vibration isolation module different, or making the unit cell directions in a single-layer vibration isolation module different, multi-directional synergistic bandgap broadening and damping can be achieved, thereby realizing multi-dimensional metamaterial synergistic vibration isolation that is different from the traditional vibration isolation support technology route;

[0107] The single layer of the support includes two end plates and a vibration damping module. The first magnetic support 1 and the second magnetic support 2 of the unit cell are fixedly connected to the first support plate 24 and the second support plate 25 belonging to the two end plates respectively.

[0108] In the length direction, the multiple end plates are connected in series through support springs 27, and the multiple unit cells and support springs 27 are arranged in parallel;

[0109] Both ends of the support spring 27 are fixedly connected to the first support plate 24 and the second support plate 25 belonging to the two end plates respectively;

[0110] In the width direction, the unit cells and the support springs 27 are arranged in an array with intervals, and in the thickness direction, the unit cells and the support springs 27 are arranged in an array with equal distances, so as to form a multi-component stiffness adjustment mechanism in which the unit cells and the springs are connected in parallel.

[0111] In this embodiment, the support plate 25 is made of steel plate to ensure that the support plate 25 has sufficient rigidity, the damping coating is made of polyacrylate coating to ensure that the damping coating has certain sliding properties, and the support spring 27 is made of carbon steel.

[0112] A metamaterial vibration isolation method employs the above-mentioned support for vibration isolation, and the specific steps are as follows:

[0113] When external excitation occurs, multiple unit cells within the vibration isolation module begin to vibrate. Due to the different relative positions of the unit cells within the module, the vibrations generated by the external excitation are different. The dynamic characteristics and stiffness change amplitudes of each unit cell are also different. The vibrations of each unit cell affect each other, forming a good low-frequency elastic wave band gap and wave guiding characteristics to isolate the low-frequency vibrations generated by the earthquake.

[0114] In the longitudinal direction, the vibration reduction modules at different positions are also controlled by external excitation. The stiffness and frequency of each vibration reduction module are different. At the same time, due to the slidability of the end plates, the stiffness and frequency of adjacent vibration reduction modules affect each other, further realizing the control of low-frequency waves and suppressing large deformation while achieving negative stiffness.

[0115] In the proposed unit cell, the present invention utilizes an electromagnet-spring-electromagnet variable stiffness unit to achieve controllable and adjustable time-varying stiffness based on an electromagnetic time-varying mechanism. In conventional vibration isolation systems, the nonlinear stiffness generated by the system component units typically has only one direction, namely positive stiffness, negative stiffness, or quasi-zero stiffness. The present invention effectively changes the magnitude of the magnetic force at both ends of the electromagnet-spring-electromagnet variable stiffness unit or alters its magnetic properties by controlling the magnitude, direction, and frequency of the current in the energized conductive plate attached to the hollow sleeve. It can even generate alternating magnetism by introducing an alternating current as required. Together with the magnetic support with constant magnetic properties, this forms a positive stiffness, negative stiffness, and quasi-zero stiffness system with adjustable vibration isolation efficiency and damping.

[0116] The present invention utilizes the characteristics of adaptive adjustment of eddy current damping to allow the unit cell to provide considerable adaptive energy consumption according to the characteristics of the movement of the electromagnet-spring-electromagnet variable stiffness unit, while reducing the influence of the self-vibration of the electromagnet-spring-electromagnet variable stiffness unit on the vibration isolation structure;

[0117] In the vibration isolation support proposed in the present invention, based on the different dynamic characteristics and stiffness change amplitudes of unit cells at different positions under external excitation, the frequency and stiffness characteristics of each vibration reduction module under the different influences of the internal unit cell dynamic characteristics and stiffness, and the mutual influence of the vibrations of each unit cell, and the mutual influence of the movements between adjacent vibration reduction modules, a good low-frequency broadened elastic wave band gap, electromagnetic damping energy dissipation and wave guiding characteristics are formed to isolate the low-frequency vibration generated by earthquakes and suppress vibration peaks, thereby realizing multi-dimensional adaptive metamaterial-type synergistic vibration isolation while avoiding the need for large-deformation vibration isolation belts concentrated in traditional flexible vibration isolation layers.

[0118] The unit cell of the present invention realizes a dual magnet-spring multi-component stiffness adjustment mechanism with the electromagnet as the core of the variable stiffness unit, and forms a stiffness adjustment element based on the dual magnet nonlinear variable stiffness structure formed by the electromagnet-spring-electromagnet variable stiffness unit and the dual magnetic supports, an adaptive series stiffness adjustment element inside the electromagnet-spring-electromagnet variable stiffness unit, a limit and parallel stiffness adjustment element inside the stiffness structure formed by the electromagnet-spring-magnetic supports, and a nonlinear damping element based on eddy current damping with the magnetic guide plate-electromagnet as the core. By enhancing The positive stiffness, negative stiffness and quasi-zero stiffness of the dual-magnet nonlinear stiffness adjustment element are artificially adjustable. Springs and eddy current dampers are added to realize stiffness adjustment mechanisms with series, parallel, adaptive and nonlinear characteristics, achieving adaptive vibration isolation based on nonlinear variable stiffness adjustment. That is, it provides an enhanced dual-magnet system, springs and eddy current damping series and parallel nonlinear joint control force under large displacement and high acceleration control requirements, realizing adaptive vibration isolation of engineering and mechanical structures under multi-level and multi-source excitation, and solving the design contradiction between deformation control of the isolation layer and vibration isolation efficiency.

[0119] The above description of the embodiments is intended to facilitate understanding and use of the invention by those skilled in the art. It will be apparent that those skilled in the art can readily make various modifications to these embodiments and apply the general principles described herein to other embodiments without requiring inventive effort. Therefore, the present invention is not limited to the above-described embodiments. 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 electromagnet nonlinear variable stiffness unit cell, characterized in that: The unit cell includes an electromagnet-spring-electromagnet variable stiffness unit, an auxiliary stiffness adjustment component, a stiffness adjustment and eddy current damping energy dissipation component, The electromagnet-spring-electromagnet variable stiffness unit comprises a first electromagnet (5), a second electromagnet (6) and a preload spring, wherein the first electromagnet (5) and the second electromagnet (6) are connected via the preload spring. The auxiliary stiffness adjustment component comprises a first magnetic support (1), a second magnetic support (2) and a hollow sleeve (19), wherein the first electromagnet (5) is connected to the first magnetic support (1) via a spring, and the second electromagnet (6) is connected to the second magnetic support (2) via a spring. The stiffness adjustment and eddy current damping energy dissipation component includes an electric conductive plate and a magnetic conductive plate, the electric conductive plate and the magnetic conductive plate are arranged on the hollow sleeve (19) at intervals, and the electromagnet-spring-electromagnet variable stiffness unit is suspended through the hollow sleeve (19); Limiting slide rails are fixedly provided on both sides of the hollow sleeve (19), and the two ends of the limiting slide rails are respectively connected to the first magnetic support (1) and the second magnetic support (2) via connecting springs; The magnetic poles of the first magnetic support (1), the original magnetic poles of the first electromagnet (5), the original magnetic poles of the second electromagnet (6), and the magnetic poles of the second magnetic support (2) are opposite to each other; By adjusting the direction, magnitude and frequency of the current in the energized conductive plate, the magnetic field in the two energized conductive plates is adjusted. The energized conductive plate generates a magnetic field inside the hollow sleeve (19). The relative horizontal movement of the electromagnet-spring-electromagnet variable stiffness unit cuts the magnetic flux lines. The first electromagnet (5) and the second electromagnet (6) inside the electromagnet-spring-electromagnet variable stiffness unit generate an induced electromotive force, and then generate an induced current, thereby changing the magnetism of the first electromagnet (5) and the second electromagnet (6), and adjusting the stiffness of the unit cell.

2. The electromagnet nonlinear variable stiffness unit cell according to claim 1, characterized in that: The pre-compression spring comprises a first pre-compression spring (14) and a second pre-compression spring (15); the inner ends of the first electromagnet (5) and the second electromagnet (6) are connected via the first pre-compression spring (14) and the second pre-compression spring (15); and the first pre-compression spring (14) and the second pre-compression spring (15) are connected in parallel.

3. The electromagnet nonlinear variable stiffness unit cell according to claim 1, characterized in that: The first electromagnet (5) and the second electromagnet (6) are respectively connected to the first magnetic support (1) and the second magnetic support (2) via an oblique spring and a horizontal spring, and the oblique spring and the horizontal spring are connected in parallel.

4. The electromagnet nonlinear variable stiffness unit cell according to claim 3, characterized in that: The outer end of the first electromagnet (5) is connected to the first magnetic support (1) through a first oblique spring (11), a first horizontal spring (12) and a second oblique spring (13); the first oblique spring (11), the first horizontal spring (12) and the second oblique spring (13) are connected in parallel; the first oblique spring (11) and the second oblique spring (13) are symmetrically arranged with respect to the first horizontal spring (12); The outer end of the second electromagnet (6) is connected to the second magnetic support (2) through a third oblique spring (16), a second horizontal spring (17) and a fourth oblique spring (18), the third oblique spring (16), the second horizontal spring (17) and the fourth oblique spring (18) are connected in parallel, and the third oblique spring (16) and the fourth oblique spring (18) are symmetrically arranged with respect to the second horizontal spring (17).

5. The electromagnet nonlinear variable stiffness unit cell according to claim 1, characterized in that: The two sides of the hollow sleeve (19) are fixedly connected oppositely to each other with a first limiting slide rail (3) and a second limiting slide rail (4). One end of the first limiting slide rail (3) is connected to the first magnetic support (1) via a first connecting spring (20), and the other end is connected to the second magnetic support (2) via a second connecting spring (21). One end of the second limiting slide rail (4) is connected to the first magnetic support (1) via a third connecting spring (22), and the other end is connected to the second magnetic support (2) via a fourth connecting spring (23).

6. The electromagnet nonlinear variable stiffness unit cell according to claim 1, characterized in that: The stiffness adjustment and eddy current damping energy dissipation component comprises a first current conducting plate (7), a second current conducting plate (8), a first magnetic conducting plate (9) and a second magnetic conducting plate (10); two opposite side surfaces of the hollow sleeve (19) are fixedly connected to the first current conducting plate (7) and the second current conducting plate (8); and two other opposite side surfaces are fixedly connected to the first magnetic conducting plate (9) and the second magnetic conducting plate (10).

7. A metamaterial vibration isolation support, characterized in that: The support includes a vibration reduction module and an end plate, wherein a plurality of end plates are connected in series via the vibration reduction module, wherein the vibration reduction module includes a plurality of parallel arrays of unit cells according to any one of claims 1 to 6; The end plate comprises a first support plate (24), a second support plate (25) and a damping coating (26), wherein the damping coating (26) is coated between the first support plate (24) and the second support plate (25).

8. The metamaterial vibration isolation support according to claim 7, characterized in that: The multiple end plates are also connected in series via support springs (27), and the multiple unit cells and support springs (27) are connected in parallel to form an array.

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