Flat plate type low-frequency vibration reduction superstructure containing multiple vibrators

Abstract

The invention relates to the field of vibration reduction metamaterials, in particular to a flat plate type low-frequency vibration reduction superstructure containing multiple vibrators. Comprising a base plate, a square hole is formed in the base plate, and a local resonance function unit is arranged in the square hole; the local resonance function unit comprises an elastic mass block arranged in the square hole; the bending beam is connected with the elastic mass block and the base body plate; one end of the bent beam is connected with the elastic mass block, the other end of the bent beam forms two symmetrically-distributed connecting arms through a forked structure, and the two connecting arms are anchored to the two mutually-orthogonal inner walls on the base plate respectively. Vibration and noise reduction in a low-frequency domain range is achieved in a limited space, and meanwhile good mechanical performance is achieved.

Description

Technical Field

[0001] The present invention relates to the field of vibration damping metamaterials, and specifically to a flat low-frequency vibration damping superstructure containing multiple oscillators. Background Art

[0002] Low-frequency vibration and noise control are common challenges in fields such as transportation, aerospace, and high-end equipment manufacturing. Considerable efforts have been made to suppress low-frequency noise and vibration, but traditional vibration suppression technologies have problems such as a narrow effective frequency band, poor robustness, and being basically ineffective in the low-frequency band.

[0003] Mechanical metamaterials are a new type of material that achieves mechanical properties unattainable by traditional materials through artificially designed micro- or mesoscopic structures. This new type of material system with unconventional mechanical responses provides a new path to break through the limitations of traditional materials in low-frequency wave regulation. By regulating the bandgap range through the mechanisms of Bragg scattering and local resonance, elastic waves can be suppressed within the bandgap frequency range to achieve the effect of vibration damping and noise reduction.

[0004] However, for these lightweight structures, dealing with low-frequency noise below 200 Hz is still challenging. Existing research shows that the realization of a low-frequency wide bandgap usually depends on a substantial increase in the number and mass of resonant units, which fundamentally conflicts with the stringent requirements for structural lightweight and compactness in practical applications. Especially under the constraint of limited installation space, the typical external resonator layout of traditional metamaterials (such as surface attachment on a panel or truss hanging) faces significant limitations, and the mechanical properties of the main load-bearing structure are also weakened. Therefore, the design of lightweight metamaterial structures for low-frequency vibration is still an urgent problem to be solved. Summary of the Invention

[0005] To solve the technical problems in the background art, the present invention provides a flat low-frequency vibration damping superstructure containing multiple oscillators, which realizes vibration damping and noise reduction in the low-frequency range within a limited space, and at the same time has good mechanical properties, and can effectively solve the problem of low-frequency vibration control of engineering structures.

[0006] The technical solution adopted by the present invention to solve its technical problems is as follows: A flat low-frequency vibration damping superstructure containing multiple oscillators, comprising: A base plate, on which a square hole is opened, and a local resonance functional unit is arranged in the square hole; The local resonance functional unit includes: An elastic mass block, arranged in the square hole; A bending beam, connecting the elastic mass block and the base plate; One end of the bent beam is connected to the elastic mass block, and the other end forms two symmetrically distributed connecting arms through a bifurcated structure. The two connecting arms are respectively anchored to two mutually orthogonal inner walls on the base plate.

[0007] Furthermore, the bent beam is composed of four beam bodies connected in sequence, and its specific structure is as follows: The first beam body is vertically and fixedly connected to the inner wall of the base plate. The second beam body extends vertically and bends from the end of the first beam body, and its extending direction is towards the geometric central axis of the square hole. The third beam body extends vertically and bends from the end of the second beam body, and its extending direction is towards the geometric central axis of the square hole. The fourth beam body extends reversely and bends from the end of the third beam body, and its extending direction is away from the geometric center of the square hole. The end of the fourth beam body is finally connected to the elastic mass block.

[0008] Furthermore, there are two of the first beam body, the second beam body and the third beam body, which are symmetrically arranged on both sides of the fourth beam body, and the fourth beam body is arranged at the confluence of the two third beam bodies.

[0009] Furthermore, the length of the first beam body is 1 / 20 - 1 / 10 of the side length of the base plate, and the distance between the first beam body and the adjacent inner wall of the base plate is 1 / 20 - 1 / 5 of the side length of the base plate; the length of the second beam body is 1 / 5 - 1 / 3 of the side length of the base plate; the widths of the first beam body, the second beam body, the third beam body and the fourth beam body are 1 / 65 - 1 / 30 of the side length of the base plate.

[0010] Furthermore, there are four local resonance functional units, and the four local resonance functional units are distributed in the square hole in a centrosymmetric manner.

[0011] Furthermore, the elastic mass block is made of resin or steel, and the materials of the two elastic mass blocks located on the diagonal of the square hole are the same.

[0012] Furthermore, the diameter of the elastic mass block is greater than 1 / 10 of the side length of the base plate and less than 1 / 4 of the side length of the base plate.

[0013] Furthermore, the elastic mass block is selected in a circular configuration.

[0014] Furthermore, the base plate is made of the same material as the elastic mass block.

[0015] The beneficial effects of the present invention: (1) The present invention realizes low-frequency vibration suppression in the sub-wavelength band by constructing a local resonance unit containing a mass block and a bifurcated curved beam, and utilizes the local resonance mechanism. When the structure is subjected to external vibration excitation, the elastic deformation of the bifurcated curved beam is coupled with the inertial motion of the mass block to form an elastic wave bandgap within a preset frequency band, causing the vibration energy transmitted into the structure to be strongly attenuated within this frequency band.

[0016] (2) The reasonable design of the structure and material parameters of the base plate, curved beam, and mass block in the present invention can change the frequency range of the bandgap and achieve effective attenuation of vibrations within a specific frequency range.

[0017] (3) The flat-type low-frequency vibration damping superstructure in the present invention has excellent mechanical properties of light weight and high load-bearing capacity. At the same time, through the cooperative action of multiple oscillators, wide-band vibration suppression can be achieved, combining structural strength and vibration damping performance.

[0018] (4) The present invention provides an adjustable vibration damping bandgap design scheme by setting multiple local resonance oscillators. Compared with traditional single-oscillator metamaterials, the present invention can achieve multi-band vibration suppression by adjusting the mass, stiffness, and spatial arrangement of different oscillators. At the same time, the coupling effect between different oscillators can enhance the local resonance effect and further improve the low-frequency vibration damping performance.

[0019] (5) The thickness of the flat-type low-frequency vibration damping superstructure in the present invention is less than 5 mm, which is relatively thin and light, and is convenient to be arranged in equipment such as automobiles, trains, airplanes, and ships. Brief Description of the Drawings

[0020] The present invention will be further described below in conjunction with the drawings and embodiments.

[0021] Figure 1 is a schematic diagram of the unit cell structure of the present invention; Figure 2 is a schematic diagram of the structure of the curved beam of the present invention; Figure 3 is a schematic diagram of the overall structure of the present invention; Figure 4 is a band structure diagram of the unit cell of the present invention; Figure 5 is a specimen diagram for testing the frequency response function; Figure 6 is a comparison diagram of the simulation and experimental results of the frequency response function test; Figure 7 is a unit cell with elastic mass blocks of different materials and the corresponding band structure diagrams, where (a) unit cells with three typical material configurations: all-steel reference type, all-photosensitive polymer resin type, and steel / photosensitive resin hybrid type, (b) band structure diagrams corresponding to the three unit cells.

[0022] In the figure: 1. Substrate plate, 2. Bending beam, 3. Elastic mass block; 21. First beam body, 22. Second beam body, 23. Third beam body, 24. Fourth beam body. Detailed implementation manners

[0023] The present invention will be further described in detail below with reference to the accompanying drawings.

[0024] As Figure 1 shown, a flat low-frequency vibration damping superstructure with multiple oscillators includes a substrate plate 1. A square hole is formed in the substrate plate 1, and a local resonance functional unit is arranged in the square hole. The local resonance functional unit includes an elastic mass block 3, and the elastic mass block 3 is arranged in the square hole. The bending beam 2 connects the elastic mass block 3 and the substrate plate 1. One end of the bending beam 2 is connected to the elastic mass block 3, and the other end forms two symmetrically distributed connecting arms through a bifurcated structure. The two connecting arms are respectively anchored to two mutually orthogonal inner walls on the substrate plate 1 to form a two-way anchoring. There are four local resonance functional units, and the four local resonance functional units are distributed in the square hole in a centrosymmetric manner. The elastic mass block 3 is selected in a circular configuration, the diameter of the elastic mass block 3 is greater than 1 / 10 of the side length of the substrate plate 1, and the diameter of the elastic mass block 3 is less than 1 / 4 of the side length of the substrate plate 1. The elastic mass block 3 can also adopt a polygon and other topological structures that meet the low-frequency vibration requirements. The substrate plate 1 is made of the same material as the elastic mass block 3, or can also be made of other materials. In a specific embodiment, the elastic mass block 3 is made of resin or steel, and the materials of the two elastic mass blocks 3 located on the diagonal of the square hole are the same. As Figure 3 shown, multiple substrate plates 1 are arranged periodically in the X and Y directions and combined to form a flat structure.

[0025] As Figure 2 shown, the bending beam 2 is composed of four beam bodies connected in sequence, and its specific structure is: the first beam body 21 is vertically fixed to the inner wall of the substrate plate 1. The second beam body 22 extends vertically and bends from the end of the first beam body 21, and its extending direction is towards the geometric central axis of the square hole. The third beam body 23 extends vertically and bends from the end of the second beam body 22, and its extending direction is towards the geometric central axis of the square hole. The fourth beam body 24 extends reversely and bends from the end of the third beam body 23, and its extending direction is away from the geometric center of the square hole. The included angle between the fourth beam body 24 and the third beam body 23 is 45°. The end of the fourth beam body 24 is finally connected to the elastic mass block 3. There are two of the first beam body 21, the second beam body 22 and the third beam body 23, which are symmetrically arranged on both sides of the fourth beam body 24, and the fourth beam body 24 is arranged at the confluence of the two third beam bodies 23.

[0026] Size and material parameters in specific embodiments: The materials of the base plate 1 and the bending beam 2 are both epoxy resin, with a Poisson's ratio of ν = 0.41, an elastic modulus of E = 2.65e9 Pa, and a density of ρ = 1110 Kg / m 3 。The material of the elastic mass block 3 is structural steel, with a Poisson's ratio of ν = 0.3, an elastic modulus of E = 200e9 Pa, and a density of ρ = 7850 Kg / m 3 。

[0027] The side length of the base plate 1 is 60 mm and the thickness is 4 mm. The length of the first beam 21 is 4.5 mm, the width is 1 mm, and the thickness is 4 mm. The distance between the first beam 21 and the inner wall of the adjacent base plate 1 is 7 mm. The length of the second beam 22 is 18 mm, the width is 1 mm, and the thickness is 4 mm. Taking the left branch of the bending beam 2 in the upper right corner as an example, this branch extends downward by 4.5 mm at a distance of 7 mm from the inner wall of the base plate 1, then turns inward by 18 mm, and then turns downward again until it converges with the right branch. After convergence, the bending beam 2 continues to extend towards the center of the elastic mass block 3 until it is connected to the elastic mass block 3. The radius of the elastic mass block 3 is 6.5 mm.

[0028] Next, the band structure diagram of the flat superstructure with the above dimensions and material parameters is calculated. As Figure 4 shown, the abscissa in the figure is the reduced wave vector, the ordinate is the frequency, and the shaded part represents the band gap, that is, the propagation of vibrations in this frequency range is suppressed in the structure. The above superstructure generates a total of three band gaps, which are 61.4 - 75.7 Hz, 142.3 - 213.1 Hz, and 214.3 - 253.6 Hz respectively.

[0029] Next, the frequency response function of the flat superstructure with the above dimensions and material parameters is tested. Figure 5 It is a specimen diagram for frequency response function testing. This specimen is a periodic metamaterial plate composed of 6×2 unit cells. The results of the frequency response function obtained through simulation and experiment are shown in Figure 6 . In the frequency range of 0 Hz to 400 Hz, the transmissivity of elastic waves in the band gap frequency range decreases significantly, indicating that vibrations are effectively attenuated in these frequency bands. From the above analysis, it can be seen that the flat metamaterial of the present invention has a very obvious low-frequency vibration reduction effect.

[0030] As Figure 7 shown, among them, (a) the unit cells of three typical material configurations are all-steel reference type, all-photosensitive polymer resin type, and steel / photosensitive resin hybrid type. Specifically: all four elastic mass blocks of the unit cell structure on the left are made of steel, all four elastic mass blocks of the unit cell structure in the middle are made of all-photosensitive polymer resin, and among the four elastic mass blocks of the unit cell structure on the right, two elastic mass blocks at the diagonal positions are made of steel, and the other two elastic mass blocks at the diagonal positions are made of all-photosensitive polymer resin.

[0031] The solution of this embodiment will be further described below in combination with the closest prior art: The Chinese patent with publication number CN112874066B discloses "A honeycomb structure board integrating vibration suppression and light weight and high strength and its preparation method", and its structure is closest to the technical solution of this embodiment.

[0032] It designs three multifunctional honeycombs, TypeA, TypeB, and TypeC. The bandgap frequencies obtained by the oscillator systems of the three structures are all around 1000 Hz, and the relative bandwidth remains at about 15%. The bandgap frequency of the flat-type superstructure proposed in this embodiment is around 200 Hz, and the relative bandwidth is 77%. The vibration damping frequency band is lower, and the relative bandwidth is increased by 413%, indicating that this embodiment has significantly excellent broadband vibration damping effect. In addition, the single oscillator system of the existing invention patent can only adjust the bandgap by changing the geometric and material parameters of the oscillator, while the oscillator system of this embodiment has a total of four local resonance oscillators, and has a more flexible vibration damping bandgap adjustment scheme. As Figure 7 shown, in the energy band structure diagram of the hybrid metamaterial obtained by combining oscillators of two materials in a unit cell, the intrinsic mode characteristics of the two base materials are retained at the same time, and the bandgap distribution range almost covers the joint interval of the bandgap regions of the two single material systems. The hybrid metamaterial has a wider bandgap in the studied frequency range, and the weight of the oscillator is reduced by 42% compared with the all-steel configuration. It shows that this embodiment can realize the synergistic optimization of bandgap broadening effect and structural light weight through the multi-material hybrid design in the oscillator and the synergistic effect of units with different bandgap frequencies.

[0033] The manufacturing method of the present invention will be described in detail below, including the following steps: Step 1: Use 3D printing technology to prepare the base plate 1 and the bent beam 2 fixedly connected thereto.

[0034] Step 2: Use laser cutting to cut the elastic mass block 3.

[0035] Step 3: Use AB glue to bond the elastic mass block 3 to one end of the bent beam 2, and keep the height of the elastic mass block 3 level with the base plate 1 and the bent beam 2 to complete the design of the flat-type superstructure.

[0036] Based on the ideal embodiment of the present invention as an inspiration, through the above description, relevant staff can completely make various changes and modifications within the scope not deviating from the technical idea of this invention. The technical scope of this invention is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A flat low-frequency vibration damping superstructure with multiple oscillators, characterized in that, Including: A base plate (1), on which a square hole is formed, and a local resonance functional unit is arranged in the square hole; The local resonance functional unit includes: An elastic mass block (3), arranged in the square hole; A bending beam (2), connecting the elastic mass block (3) and the base plate (1); One end of the bending beam (2) is connected to the elastic mass block (3), and the other end forms two symmetrically distributed connecting arms through a bifurcated structure, and the two connecting arms are respectively anchored to two mutually orthogonal inner walls on the base plate (1).

2. The flat low-frequency vibration damping superstructure with multiple oscillators according to claim 1, characterized in that The bending beam (2) is composed of four beam bodies connected in sequence, and its specific structure is: A first beam body (21), and the first beam body (21) is vertically and fixedly connected to the inner wall of the base plate (1); A second beam body (22), and the second beam body (22) extends vertically and bent from the end of the first beam body (21), and its extending direction is towards the geometric central axis of the square hole; A third beam body (23), and the third beam body (23) extends vertically and bent from the end of the second beam body (22), and its extending direction is towards the geometric central axis of the square hole; A fourth beam body (24), and the fourth beam body (24) extends reversely and bent from the end of the third beam body (23), and its extending direction is away from the geometric center of the square hole, and the end of the fourth beam body (24) is finally connected to the elastic mass block (3).

3. The flat low-frequency vibration damping superstructure with multiple oscillators according to claim 2, characterized in that There are two of the first beam body (21), the second beam body (22) and the third beam body (23), which are symmetrically arranged on both sides of the fourth beam body (24), and the fourth beam body (24) is arranged at the confluence of the two third beam bodies (23).

4. The flat low-frequency vibration damping superstructure with multiple oscillators according to claim 3, characterized in that The length of the first beam body (21) is 1 / 20 - 1 / 10 of the side length of the base plate (1), and the distance between the first beam body (21) and the adjacent inner wall of the base plate (1) is 1 / 20 - 1 / 5 of the side length of the base plate (1); the length of the second beam body (22) is 1 / 5 - 1 / 3 of the side length of the base plate (1); the widths of the first beam body (21), the second beam body (22), the third beam body (23) and the fourth beam body (24) are 1 / 65 - 1 / 30 of the side length of the base plate (1).

5. The flat low-frequency vibration damping superstructure with multiple oscillators according to claim 1, characterized in that There are four local resonance functional units, and the four local resonance functional units are distributed in the square hole in a centrosymmetric manner.

6. The flat low-frequency vibration damping superstructure with multiple oscillators according to claim 5, characterized in that The elastic mass block (3) is made of resin or steel, and the materials of the two elastic mass blocks (3) located on the diagonal of the square hole are the same.

7. The flat low-frequency vibration damping superstructure with multiple oscillators according to claim 1, characterized in that The diameter of the elastic mass block (3) is greater than 1 / 10 of the side length of the base plate (1), and the diameter of the elastic mass block (3) is less than 1 / 4 of the side length of the base plate (1).

8. The flat low-frequency vibration damping superstructure with multiple oscillators according to claim 1, wherein the elastic mass block (3) is selected to have a circular configuration.

9. The flat low-frequency vibration damping superstructure with multiple oscillators according to claim 1, wherein the base plate (1) is made of the same material as the elastic mass block (3).

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