A vibration-damping metamaterial beam based on magnetically coupled oscillators

Abstract

The present invention discloses a vibration-damping metamaterial beam based on magnetically coupled oscillators, which relates to the technical field of vibration-damping devices, and includes: a main structure cantilever beam, a substructure cantilever beam, a magnet, a clamp, and a mass block. Specifically: the main structure cantilever beam is a thin beam structure with equal cross-section; the main structure cantilever beam is divided into n sections, and a pair of substructure cantilever beams are added to one side of each section of the beam to form a unit cell. The free end of the substructure cantilever beam is fixed with a mass block, and an L-shaped clamp is added between the substructure cantilever beam and the mass block to ensure that the mass block can be fixed on the substructure cantilever beam; the magnet is embedded in the mass block. By adjusting the magnetic spacing, the size and characteristics of the nonlinear magnetic force are changed. The metamaterial beam based on nonlinear magnetic coupling of the present invention can achieve bandgap widening at low frequencies, thereby improving the low-frequency vibration suppression performance.

Description

Technical Field

[0001] The present invention relates to the technical field of vibration reduction devices, and in particular to a vibration reduction metamaterial beam based on magnetic coupling oscillators. Background Art

[0002] Acoustic metamaterials refer to artificial materials with extraordinary physical properties. Their bandgap characteristics can effectively suppress the transmission of waves and have good potential for vibration reduction and noise reduction. Among them, local resonance metamaterials have developed rapidly in recent years and have become one of the effective methods for structural vibration reduction. For example, in the prior art, acoustic metamaterial-type light wall panels are designed using local resonance acoustic metamaterials. Compared with ordinary structures, acoustic metamaterial wall panels have excellent vibration suppression effects within the bandgap frequency range (220.5-311.9Hz). In the prior art, there is also an internally coupled local resonance metamaterial beam proposed by connecting adjacent local resonance oscillators. This method can obtain three band gaps, and the total width of the band gap is also greatly improved, realizing broadband vibration reduction. However, whether it is multiple local resonance oscillators or internally coupled local resonance oscillators, although the number of band gaps can be increased, these adjacent band gaps cannot be completely merged into a single broadband band gap, which makes it difficult for linear local resonance metamaterials to completely avoid the appearance of passbands in broadband vibration reduction applications.

[0003] In recent years, due to the good broadband characteristics of nonlinear oscillators, nonlinear oscillators have been introduced into local resonance metamaterials to achieve bandgap widening. For example, a nonlinear metamaterial based on nonlinear capacitors has been proposed in the prior art. The experimental results show that nonlinear capacitors can widen the bandgap by 3~15Hz. There are also metamaterial beams and plates designed with collision nonlinear structures as local resonance oscillators. The results show that the vibration transmission rate in the frequency band of 30~1200Hz is reduced by 15~40dB, achieving broadband vibration reduction. Compared with medium and high frequency vibration reduction, low-frequency vibration reduction is more challenging, and the range of local resonance bandgap is narrower. In order to obtain a wider low-frequency bandgap, the stiffness of the local resonance oscillator can be reduced or its mass can be increased. However, low stiffness will bring reliability problems, and large mass will increase the total weight of the structure, resulting in great limitations in practical engineering applications. Summary of the invention

[0004] In order to solve the above-mentioned technical defects and widen the low-frequency bandgap, the present invention proposes a nonlinear local resonance metamaterial based on magnetically coupled oscillators; compared with the traditional broadband metamaterial based on single-degree-of-freedom nonlinear oscillators, the metamaterial based on magnetically coupled two-degree-of-freedom nonlinear oscillators of the present invention has more bandgap numbers and a wider bandgap range, and is expected to achieve broadband vibration reduction in the low-frequency range.

[0005] The present invention uses a nonlinear magnetic coupling vibrator to obtain a broadband bandgap in a low-frequency range. For classic linear local resonance metamaterials, the width of the bandgap usually narrows as the bandgap frequency decreases. This results in a very narrow bandgap width and poor vibration suppression capability in the low-frequency band. In order to obtain a widened low-frequency bandgap, the most direct method is to increase the mass of the vibrator. However, in fields such as aerospace, the restrictions on structural weight are very strict. Therefore, the method of widening the low-frequency bandgap by increasing the mass of the vibrator in the present invention has many limitations in practical applications. Another method of widening the bandgap is to use multiple resonators or multi-degree-of-freedom vibrators as local resonance vibrators. Although this method can increase the number of bandgap, there are obvious passbands between different bandgap, so it is difficult to efficiently suppress vibration in a continuous frequency band. To this end, the present invention proposes a broadband metamaterial beam based on a nonlinear magnetic coupling vibrator, which uses the broadband characteristics of the nonlinear magnetic coupling vibrator to achieve the widening of the low-frequency bandgap and improve the low-frequency vibration suppression effect.

[0006] The present invention is achieved in that:

[0007] A vibration-damping metamaterial beam based on magnetic coupling oscillators comprises: a main structure cantilever beam, a substructure cantilever beam, a magnet, a clamp and a mass block, wherein the main structure cantilever beam is a thin beam structure with equal cross-section; the main structure cantilever beam is divided into n sections, and a pair of substructure cantilever beams are added to one side of each section of the beam to form a unit cell; the mass block is fixed to the free end of the substructure cantilever beam, and an L-shaped clamp is added between the substructure cantilever beam and the mass block to ensure that the mass block can be fixed on the substructure cantilever beam; the magnet is embedded in the mass block, and the size and characteristics of the nonlinear magnetic force are changed by adjusting the magnetic spacing.

[0008] Furthermore, the material of the main structure cantilever beam is stainless steel; the length of the main structure cantilever beam is L, the width is b, and the thickness is h; the left end of the beam is a fixed constraint, and the right end is a free boundary; the main beam is divided into n sections, and the length of each section is L / n, which corresponds to the length of the metamaterial unit cell; a pair of substructure cantilever beams in each unit cell are respectively called beam A and beam B.

[0009] Furthermore, the material and thickness of the substructure cantilever beam are the same as those of the main structure cantilever beam, that is, the material of the substructure cantilever beam is stainless steel, the thickness of the substructure cantilever beam is hb, and the main structure cantilever beam and the substructure cantilever beam are processed as one piece; a pair of substructure cantilever beams in each unit cell have the same thickness hb (0.5mm~1mm) and length lb (15~40mm), and the size and material of the mass block are the same, that is, the size is la×ba×ha, and the material is 8200pro resin.

[0010] Further, in order to obtain two different low-frequency bandgap, the resonant frequencies of the pair of substructure cantilever beams are different, and the resonant frequency of the local resonance oscillator is changed by changing the width of the substructure cantilever beam; the width of beam A is set to be different from the width of beam B, and the width wb1 of beam A is smaller than the width wb2 of beam B, and the width wb needs to be determined according to the cantilever beam equivalent stiffness calculation formula K=3EI / L3; the distance d1 between two adjacent unit cells is much larger than the distance d2 between beam A and beam B in each unit cell, so as to avoid the generation of magnetic force between the two unit cells and cause mutual influence. That is, the distance d1 between two adjacent unit cells is greater than the distance d2 between beam A and beam B in each unit cell by more than 15mm, so as to avoid the generation of magnetic force between the two unit cells and cause mutual influence.

[0011] Furthermore, the mass blocks are all the same, made of 3D printed material, and their mass needs to be calculated and determined based on the resonant frequency calculation formula of the structure; a magnet is embedded in each mass block, and the shape of the magnet is circular; the magnets placed face to face have the same poles, generating magnetic repulsion; the volume of the magnet will also have a certain influence on the nonlinear magnetic force. Matlab is used to calculate that when the volume of the magnet is V, the bandgap generated is the widest and the vibration reduction effect is the best.

[0012] Furthermore, in order to facilitate the adjustment of the magnetic spacing, the structure of the mass block was adjusted: two cylindrical grooves were dug in the mass block, namely the first groove and the second groove (the diameter of the first groove is larger than the diameter of the second groove); the centers of the two grooves are the same and located at the center of the surface;

[0013] The first groove is used to place the magnet, and the second groove is used to place the screw; the diameters of the first groove and the second groove are slightly larger than the diameters of the magnet and the screw, respectively, so as to facilitate the movement and placement of the screw and the magnet; the sum of the heights of the two grooves is larger than the length of the mass block, so as to facilitate the fixing of the screw; the screw is fixed under the magnet, and the distance between the two magnets is changed by moving the screw;

[0014] When the distance between the two magnets is large, the magnetic force between the two magnets is almost zero, and the local resonance oscillator degenerates into a traditional linear local resonance metamaterial beam; when the distance between the magnets is reduced to a certain extent, the nonlinear magnetic force between the two magnets will increase significantly, thereby realizing the nonlinear coupling of the local resonance oscillator.

[0015] Furthermore, the clamp between the substructure cantilever beam and the mass block is composed of two L-shaped clamps, and the material thereof is 3D printing material.

[0016] The beam structure is a common structure widely used in aerospace, automobile, construction and other fields. By suppressing the propagation of elastic waves on the beam structure, the vibration of the entire structure can be effectively suppressed. The main purpose of the present invention is to improve the low-frequency vibration reduction performance and bandwidth of the beam structure. The carrier of the vibration reduction is an ordinary thin beam structure with equal cross-section, and its material is usually steel, aluminum or 3D printing material. The length of the beam is L, the width is b, and the thickness is h. The boundary conditions at both ends of the beam are arbitrary.

[0017] In order to obtain a low-frequency bandgap, the first inventive point of the present invention is the design of a vibration-damping periodic structure. First, the main beam is divided into n sections, and the length of each section is L / n, which corresponds to the length of the metamaterial unit cell. Then, a pair of cantilever beams, namely beam A and beam B, are added on one side of each section of the beam. A mass block is fixed to the free end of the beam. During actual production, it is necessary to add an L-shaped clamp between the beam and the mass block to ensure that the mass block can be fixed on the cantilever beam. Since the bandgap frequency of the local resonance metamaterial beam is the natural frequency of the small oscillator, in order to obtain a low-frequency bandgap, it is necessary to reduce the natural frequency of the small oscillator. The small oscillator in the present invention is a cantilever beam substructure, and its resonant frequency depends on the equivalent stiffness and equivalent mass of the structure. The equivalent stiffness can be adjusted by changing the size of the beam, and the equivalent mass can be adjusted by controlling the weight of the free end mass block. In order to obtain a low-frequency (5-25Hz) bandgap, the cantilever beam selected in the present invention is made of stainless steel, with a relatively thin thickness hb, generally between 0.5mm and 1mm; the length lb is generally 15-40mm; the width wb needs to be determined according to the cantilever beam equivalent stiffness calculation formula. The mass block at the free end is generally made of stainless steel, aluminum or 3D printing material, and its mass needs to be calculated and determined according to the resonant frequency calculation formula of the structure.

[0018] It is worth noting that in order to obtain two different low-frequency bandgaps, the resonant frequencies of the pair of substructure cantilever beams are different. The resonant frequency of the local resonant oscillator can be changed by changing the width of the cantilever beam. The thickness and length of the two cantilever beam substructures are the same, and the mass blocks at the free ends are also the same. The main reason is to facilitate the subsequent design of nonlinear magnetic forces. After designing the two cantilever beam substructures, a pair of these structures are added to the same position of each section of the main beam structure (that is, in each unit cell), and a local resonant metamaterial beam structure with two low-frequency bandgaps is obtained.

[0019] However, although the metamaterial beam at this time has two forbidden bands, there is a passband between the two forbidden bands, so it is difficult to form a unified broadband forbidden band. In order to solve this problem, the second invention point of the present invention is the design of a nonlinear magnetic coupling oscillator. In each unit cell, the two cantilever beam substructures are coupled through nonlinear magnetic force. The specific implementation method is to embed a permanent magnet in the mass block at the free end of the cantilever beam. The magnet shape is generally round or square. The magnetic poles of this pair of magnets placed face to face are the same, so there is a direct magnetic repulsion between the two magnets. When the distance between the magnets is large, the magnetic force between the two magnets is almost zero, and the local resonance oscillator degenerates into a traditional linear local resonance metamaterial beam; when the distance between the magnets is reduced to a certain extent, the nonlinear magnetic force between the two magnets will increase significantly, thereby realizing the nonlinear coupling of the local resonance oscillator. Therefore, the size and characteristics of the nonlinear magnetic force can also be changed by adjusting the magnetic distance.

[0020] It is worth noting that the smaller the magnetic spacing, the better. The magnitude of the nonlinear magnetic force will directly affect the bandgap performance of the entire local resonance oscillator. Therefore, the design of the nonlinear magnetic force is the key. In the entire coupled oscillator, the equivalent stiffness of the cantilever beam is positive stiffness, and the stiffness generated by the magnetic repulsion is negative stiffness. Therefore, as the amplitude of the equivalent negative stiffness of the nonlinear magnetic force becomes larger and larger (the corresponding magnetic spacing becomes smaller and smaller), the overall equivalent stiffness of the local resonance oscillator will gradually change from positive stiffness to negative stiffness. When the equivalent stiffness of the local resonance oscillator is positive, the local resonance oscillator still has two obvious low-frequency bandgaps; when the equivalent stiffness of the local resonance oscillator becomes negative, the local resonance oscillator will only retain a continuous and unified bandgap, and the width of the bandgap is also wider. Figure 3 The transmissibility of the metamaterial beam before and after magnetic coupling is given. It can be clearly seen from the figure that a continuous broadband bandgap can be obtained by utilizing nonlinear magnetic coupling. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of the structure of a vibration-damping metamaterial beam and its dimensions provided by an embodiment of the present invention;

[0022] Figure 2 It is a schematic diagram of the structure of a unit cell and a detailed diagram;

[0023] Figure 3 is the transfer characteristic diagram of the nonlinear magnetically coupled metamaterial beam;

[0024] Among them, 1-main structure cantilever beam, 2-substructure cantilever beam, 3-magnet, 4-clamp, 5-mass block, 6-first groove, 7-second groove; d1 is the distance between two adjacent unit cells, and d2 is the distance between beam A and beam B in each unit cell. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the drawings and specific embodiments. The embodiments of the present invention will be described in detail below, and examples of the embodiments are shown in the drawings. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present invention, but cannot be interpreted as limiting the present invention. It can be understood by those skilled in the art that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as the general understanding of ordinary technicians in the field to which the present invention belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have a meaning consistent with the meaning in the context of the prior art, and will not be interpreted with an idealized or overly formal meaning unless defined as here.

[0026] This embodiment specifically provides a vibration-damping metamaterial beam based on magnetic coupling oscillators, such as Figure 1 As shown, it includes: a main structure cantilever beam 1, a substructure cantilever beam 2, a magnet 3, a fixture 4, and a mass block 5. Specifically:

[0027] The main structure cantilever beam 1 is a thin beam structure with equal cross-section; the main structure cantilever beam 1 is divided into n A pair of substructure cantilever beams 2 are added to one side of each beam segment to form a unit cell. The free end of the substructure cantilever beam 2 is fixed with a mass block 5. An L-shaped clamp is added between the substructure cantilever beam 2 and the mass block 5 to ensure that the mass block 5 can be fixed on the substructure cantilever beam 2; the magnet 3 is embedded in the mass block 5. By adjusting the magnetic spacing, the size and characteristics of the nonlinear magnetic force can be changed.

[0028] like Figure 1 As shown, the main structure cantilever beam 1 is made of stainless steel. The length of the beam is L , the width is b , thickness is h The left end of the beam is a fixed constraint, and the right end is a free boundary. The main beam is divided into n The length of each segment is L / n , which corresponds to the length of the metamaterial unit cell. A pair of substructure cantilever beams 2 in each unit cell are called beam A and beam B respectively.

[0029] The material and thickness of the substructure cantilever beam 2 are the same as those of the main structure cantilever beam 1, and the two are processed as one piece. h b (0.5mm~1mm) and length l b(15~40mm) is the same, and the mass block 5 is also the same. In order to obtain two different low-frequency band gaps, the resonant frequencies of the substructure cantilever beams are different. The resonant frequency of the local resonant oscillator can be changed by changing the width of the cantilever beam. Set the width of beam A to be different from the width of beam B, and the width of beam A w b1 Smaller than the width of beam B w b2 , Width w b It is necessary to calculate the equivalent stiffness of the cantilever beam according to the formula K =3 EI / L 3 The distance between two adjacent unit cells is d 1 Much larger than the distance between beams A and B in each unit cell d 2 , in order to avoid the generation of magnetic force between the two cells and cause mutual influence.

[0030] The mass blocks 5 are all the same, made of 3D printed material, and their mass needs to be calculated and determined according to the resonant frequency calculation formula of the structure. A permanent magnet is embedded in each mass block 5, and the shape of the magnet is round. The magnets placed face to face have the same magnetic poles, generating magnetic repulsion. The volume of the magnet will also have a certain influence on the nonlinear magnetic force. Matlab is used to calculate that when the volume of the magnet is V When , the bandgap is the widest and the vibration reduction effect is the best. In order to adjust the magnetic spacing as simply as possible, the structure of the mass block 5 is adjusted, such as Figure 2 As shown in the bottom figure: In order to facilitate the adjustment of the magnetic spacing, the structure of the mass block is adjusted: two cylindrical grooves are dug in the mass block, namely the first groove 6 and the second groove 7 (the diameter of the first groove 6 is larger than the diameter of the second groove 7); the centers of the two grooves are the same and are located at the center of the surface. The first groove 6 is used to place the magnet, and the second groove 7 is used to place the screw. The diameters of the first groove 6 and the second groove 7 are slightly larger than the diameters of the magnet and the screw, respectively, which facilitates the movement and placement of the screw and the magnet. The sum of the heights of the two grooves is larger than the length of the mass block 5, which facilitates the fixing of the screw. The screw is fixed under the magnet, and the distance between the two magnets is changed by moving the screw. When the distance between the magnets is large, the magnetic force between the two magnets is almost zero, and the local resonance oscillator degenerates into a traditional linear local resonance metamaterial beam; when the distance between the magnets is reduced to a certain extent, the nonlinear magnetic force between the two magnets will increase significantly, thereby realizing the nonlinear coupling of the local resonance oscillator.

[0031] The clamp 4 between the substructure cantilever beam 2 and the mass block 5 is composed of two L-shaped clamps, and the material thereof is 3D printing material.

[0032] On the basis of the traditional linear metamaterial theoretical model, the influence of nonlinear magnetic force and other factors on the transmissibility is added. By optimizing the size of various parameters such as magnetic spacing, magnet volume, beam cross-sectional area, etc., the widest bandgap of vibration reduction frequency is obtained. The results are as follows Figure 3 As shown. Figure 3 It can be seen that when magnetic coupling is not added, two low-frequency bandgap appear due to the different natural frequencies of the cantilever beam of the substructure in each unit cell; after magnetic coupling is added, the two small bandgap are merged into a large bandgap, and the total bandgap range is wider than the total bandgap range without magnetic coupling. The broadband characteristics of the nonlinear magnetic coupling oscillator are used to widen the low-frequency bandgap and enhance the low-frequency vibration suppression effect.

[0033] The vibration-damping metamaterial beam of the present invention obtains a continuous wideband bandgap in the low-frequency range, broadening the low-frequency vibration suppression effect of the beam structure. The specific effect can be determined by comparing and analyzing the transmissibility characteristics of the metamaterial beams without magnetic force and with magnetic local resonance.

[0034] Assuming the length of the main beam L The length is 280mm, the width is 15mm, and the thickness is 1mm. The entire beam is divided into 3 sections, namely 3 unit cells, and the length of each unit cell is 56mm. The length and height of the two cantilever beams are 40mm and 1mm respectively, of which the width of beam A is 3mm and the width of beam B is 6mm. The mass blocks at the free ends of the two beams are the same, with dimensions of 18mm×15mm×14mm and made of 8200pro resin. There is a circular groove on the opposite side of the two mass blocks, which is mainly used to place magnets. The diameter of the magnet is 12mm, the height is 3mm, the volume is 108Π, and the magnetic field strength is 0.955×10 6 A / m. The specific embodiments of the present invention ( Figure 3 ) gives the transfer characteristics of the entire metamaterial beam when there is no magnetic coupling and the magnetic spacing is 12mm. As can be seen from the figure, when there is no nonlinear magnetic coupling, the local resonance oscillator has two local resonance band gaps, which are 13.2Hz~14.5Hz and 16.4Hz~23.3Hz, and the corresponding band gap bandwidths are 1.3Hz and 6.9Hz. There is also a passband (14.5Hz~16.4Hz) between these two band gaps. When nonlinear magnetic coupling is added, the band gap of the local resonance oscillator changes from 2 to 1, with a frequency band range of 14.7Hz~23.3Hz and a bandwidth of 8.6Hz. This verifies that this metamaterial beam based on nonlinear magnetic coupling can achieve band gap widening at low frequencies, thereby improving the low-frequency vibration suppression performance.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A vibration-damping metamaterial beam based on magnetically coupled oscillators, characterized in that: The vibration-damping metamaterial beam comprises: a main structure cantilever beam (1), a substructure cantilever beam (2), a magnet (3), a clamp (4), and a mass block (5); the main structure cantilever beam (1) is a thin beam structure with a uniform cross-section; The main structure cantilever beam (1) is divided into n sections, and a pair of substructure cantilever beams (2) are added to one side of each section of the beam to form a unit cell; the free end of the substructure cantilever beam (2) is fixed with a mass block (5), and a clamp (4) is added between the substructure cantilever beam (2) and the mass block (5) to ensure that the mass block (5) can be fixed on the substructure cantilever beam (2); the magnet (3) is embedded in the mass block (5), and the magnitude and characteristics of the nonlinear magnetic force are changed by adjusting the magnetic spacing; the material and thickness of the substructure cantilever beam (2) are the same as those of the main structure cantilever beam (1), that is, the material of the substructure cantilever beam (2) is stainless steel, the thickness of the substructure cantilever beam (2) is hb, and the main structure cantilever beam (1) and the substructure cantilever beam (2) are processed as one piece; the pair of substructure cantilever beams (2) in each unit cell have the same thickness hb and length lb, both of which are 15 to 40 mm; The mass block (5) has the same size and material, and the material is 8200pro resin; the pair of substructure cantilever beams (2) have different resonance frequencies, and the pair of substructure cantilever beams (2) in each unit cell are respectively called beam A and beam B, and the resonance frequency of the local resonance oscillator is changed by changing the width of the substructure cantilever beam (2); the width of beam A is different from the width of beam B, and the width wb1 of beam A is smaller than the width wb2 of beam B; the distance d1 between two adjacent unit cells is greater than the distance d2 between beam A and beam B in each unit cell by more than 15 mm.

2. The vibration-damping metamaterial beam based on magnetic coupling oscillators according to claim 1, characterized in that: The main structure cantilever beam (1) is made of stainless steel; the main structure cantilever beam (1) has a length of L, a width of b, and a thickness of h; the left end of the beam is a fixed constraint, and the right end is a free boundary; the main beam is divided into n sections, and the length of each section is L / n, which corresponds to the length of the metamaterial unit cell.

3. The vibration-damping metamaterial beam based on magnetic coupling oscillators according to claim 1, characterized in that: The mass blocks (5) are all the same and made of 3D printed material. The mass is determined by calculation according to the resonant frequency calculation formula of the structure. A magnet (3) is embedded in each mass block (5), and the magnet (3) is circular in shape. The magnets placed face to face have the same magnetic poles, generating magnetic repulsion. The volume of the magnet has an influence on the nonlinear magnetic force. Matlab is used to calculate that when the volume of the magnet is V, the bandgap generated is the widest and the vibration reduction effect is the best.

4. The vibration-damping metamaterial beam based on magnetic coupling oscillators according to claim 1, characterized in that: The width wb1 of beam A is smaller than the width wb2 of beam B. The width wb is calculated according to the equivalent stiffness formula of the cantilever beam: K =3 EI / L 3 to confirm.

5. The vibration-damping metamaterial beam based on magnetic coupling oscillators according to claim 1, characterized in that: In order to facilitate the adjustment of the magnetic spacing, the structure of the mass block (5) is adjusted: two cylindrical grooves are dug in the mass block (5), namely a first groove (6) and a second groove (7); the diameter of the first groove (6) is larger than the diameter of the second groove (7); the centers of the two grooves are the same and are located at the center of the surface; The first groove (6) is used to place the magnet (3), and the second groove (7) is used to place the screw; the diameters of the first groove (6) and the second groove (7) are slightly larger than the diameters of the magnet and the screw, respectively, so as to facilitate the movement and placement of the screw and the magnet; the sum of the heights of the two grooves is larger than the length of the mass block (5), so as to facilitate the fixing of the screw; the screw is fixed under the magnet, and the distance between the two magnets is changed by moving the screw.

6. The vibration-damping metamaterial beam based on magnetic coupling oscillators according to claim 1, characterized in that: The clamp (4) between the substructure cantilever beam (2) and the mass block (5) is composed of two L-shaped clamps, and the material thereof is 3D printing material.

7. A vibration-damping metamaterial beam based on magnetically coupled oscillators according to any one of claims 1 to 6, characterized in that: When the distance between the two magnets is large, the magnetic force between the two magnets is almost zero, and the local resonance oscillator degenerates into a traditional linear local resonance metamaterial beam. When the distance between the two magnets is reduced to a certain extent, the nonlinear magnetic force between the two magnets will increase significantly, thereby realizing the nonlinear coupling of the local resonance oscillator. By adjusting the magnetic spacing, the magnitude and characteristics of the nonlinear magnetic force can be changed; The magnitude of the nonlinear magnetic force directly affects the bandgap performance of the entire local resonance oscillator: in the entire coupled oscillator, the equivalent stiffness of the cantilever beam is positive stiffness, and the stiffness generated by the magnetic repulsion is negative stiffness. Therefore, as the amplitude of the equivalent negative stiffness of the nonlinear magnetic force becomes larger and larger, and the corresponding magnetic spacing becomes smaller and smaller, the overall equivalent stiffness of the local resonance oscillator will gradually change from positive stiffness to negative stiffness; when the equivalent stiffness of the local resonance oscillator is positive, the local resonance oscillator has two obvious low-frequency bandgaps; and when the equivalent stiffness of the local resonance oscillator becomes a negative number, the local resonance oscillator will only retain a continuous and unified bandgap, and the width of the bandgap is also wider.

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