Spiral acoustic black hole structure and acoustic black hole damping device

Abstract

The invention discloses a spiral acoustic black hole structure and an acoustic black hole damping device, and relates to the technical field of damping and noise reduction equipment, the spiral acoustic black hole structure comprises at least one spiral acoustic black hole body, at least one first magnet device and at least one second magnet device, each acoustic black hole body is used for being connected with a controlled structure; each acoustic black hole body is connected with at least one first magnet device, the controlled structure is connected with at least one second magnet device, and magnetic force between each first magnet device and the corresponding second magnet device or between the adjacent second magnet devices can provide support for each acoustic black hole body in the first direction. The first direction is opposite to the gravity direction of each acoustic black hole body. According to the invention, low-frequency and broadband vibration reduction can be realized, the service life is prolonged, and the design space of the acoustic black hole is saved.

Description

Technical Field

[0001] The present invention relates to the technical field of vibration reduction and noise reduction equipment, and in particular to a spiral acoustic black hole structure and an acoustic black hole vibration reduction device. Background Art

[0002] The Acoustic Black Hole (ABH) effect utilizes the gradient change of the geometric parameters or material property parameters of thin-walled structures to gradually reduce the propagation speed of waves in thin-walled structures. Ideally, the wave speed can be reduced to zero, and no reflection occurs. ABH has the characteristics of high bandwidth and efficiency, simple and flexible implementation methods for wave aggregation. It has obvious advantages in applications such as vibration reduction and noise reduction of thin-walled structures and energy recovery, especially in the field of vibration reduction and noise reduction of aerospace engineering structures. However, in applications, due to the long wavelength of low-frequency waves, it is difficult to fully decelerate them in an ABH of limited size, resulting in limited low-frequency vibration reduction effects. At the same time, the existing spiral acoustic black hole structure has poor stiffness, which can easily cause the head end of the spiral acoustic black hole structure to sag, and then contact and collide with the controlled structure, affecting the vibration reduction effect and service life. Summary of the Invention

[0003] The purpose of the present invention is to provide a spiral acoustic black hole structure and an acoustic black hole vibration reduction device to solve the problems existing in the above-mentioned prior art, which can achieve low-frequency and broadband vibration reduction, extend the service life, and help save the design space of the acoustic black hole.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] The present invention provides a spiral acoustic black hole structure, comprising at least one spiral acoustic black hole body, at least one first magnet device and at least one second magnet device, each of the acoustic black hole bodies being used to be connected to a controlled structure; each of the acoustic black hole bodies is connected to at least one first magnet device, and the controlled structure is connected to at least one second magnet device, and the magnetic force between each of the first magnet devices and the second magnet device or the adjacent second magnet device can provide support for each of the acoustic black hole bodies along a first direction, where the first direction is opposite to the direction of gravity of each of the acoustic black hole bodies.

[0006] Preferably, at least N of the acoustic black hole bodies are arranged in sequence along the vertical direction on the same side of the controlled structure, N≥2 and N is an integer, and the direction of the resultant magnetic force between the first magnet device of each acoustic black hole body and the first magnet devices of all other acoustic black hole bodies and all the second magnet devices is opposite to the first direction.

[0007] Preferably, the acoustic black hole body close to the controlled structure is the first acoustic black hole body, the end of the magnet device on the first acoustic black hole body close to the controlled structure has the same polarity as the end of the magnet device on the controlled structure close to the first acoustic black hole body, and the end of the magnet device on the Nth acoustic black hole body close to the controlled structure has the same polarity as the end of the magnet device on the N-1th acoustic black hole body away from the controlled structure.

[0008] Preferably, the first magnet device on the first acoustic black hole body corresponds one-to-one to the second magnet device on the controlled structure, and the first magnet devices on the two adjacent acoustic black hole bodies correspond one-to-one. Each of the first magnet devices on each acoustic black hole body can form a nonlinear magnetic coupling with the corresponding first magnet device on the adjacent acoustic black hole body, and each of the second magnet devices can form a nonlinear magnetic coupling with the corresponding first magnet device on the adjacent acoustic black hole body.

[0009] Preferably, it also includes at least one connecting column, each of the acoustic black hole bodies is sleeved outside one of the connecting columns and fixedly connected to the corresponding connecting column, each of the connecting columns is sleeved with at least one of the acoustic black hole bodies, and each of the connecting columns is fixedly connected to the controlled structure.

[0010] Preferably, each of the acoustic black hole bodies includes at least one acoustic black hole slat, and each of the acoustic black hole bodies is formed by all the acoustic black hole slats spirally curled around the same axis and in the same direction; the inner end of each of the acoustic black hole slats is fixedly connected to the connecting column, and the outer end of each of the acoustic black hole slats is provided with at least one of the first magnet devices.

[0011] Preferably, each of the acoustic black hole slats includes a first slat segment and a second slat segment arranged in sequence, and each of the first slat segments is a variable thickness segment; when each of the acoustic black hole slats is fully unfolded, the thickness of each of the first slat segments gradually decreases from one end close to the second slat segment to the other end; each of the second slat segments can be fixedly connected to the corresponding connecting column.

[0012] Preferably, when each of the acoustic black hole slats is fully unfolded, the thickness of each of the first slat segments decreases in the form of a power function from one end close to the second slat segment to the other end.

[0013] Preferably, it further comprises at least one damping member, and each of the first slat segments is connected to at least one of the damping members.

[0014] This embodiment also provides an acoustic black hole vibration reduction device, which is provided with at least one spiral acoustic black hole structure as described above.

[0015] Compared with the prior art, the present invention has achieved the following technical effects:

[0016] The present invention provides a spiral acoustic black hole structure and an acoustic black hole vibration reduction device, comprising at least one spiral acoustic black hole body, at least one first magnet device, and at least one second magnet device. Each acoustic black hole body is connected to a controlled structure. Each acoustic black hole body is connected to at least one first magnet device, and the controlled structure is connected to at least one second magnet device. The magnetic force between each first magnet device and the second magnet device, or between each adjacent second magnet device, can provide support for each acoustic black hole body in a first direction, which is opposite to the direction of gravity of each acoustic black hole body. The acoustic black hole body is used to absorb and dissipate vibration energy on the controlled structure. The magnetic force between the first magnet device and the second magnet device, or between the first magnet device and the corresponding adjacent first magnet device, can offset the gravity of the acoustic black hole body, provide support for the acoustic black hole body, increase the stiffness of the acoustic black hole body, and thereby improve the robustness of the acoustic black hole body, prevent the acoustic black hole body from sagging under the action of gravity, and prevent the acoustic black hole body from contacting and colliding with the controlled structure, thereby improving the vibration reduction effect and extending the service life. At the same time, by providing a first and second magnet assembly, the first and second magnet assemblies, as well as the first and adjacent first magnet assemblies, can interact and form nonlinear magnetic coupling, thereby broadening the low-frequency action band of the acoustic black hole and improving the damping effect on low-frequency vibrations. During vibration, the spacing between the interacting magnet assemblies changes, causing the magnetic force between the magnet assemblies to vary, which can give the structure variable stiffness and resonate with structures of various natural frequencies, achieving low-frequency and broadband vibration damping. Because the magnet assemblies do not contact each other, stiffness degradation is less likely to occur, resulting in greater stability and a longer service life. The acoustic black hole body is configured in a spiral shape, which helps save design space for the acoustic black hole and enables a lower fundamental frequency design and higher modal density. This enhances low-frequency modal coupling, making the acoustic black hole effect more likely to occur, and provides good low-frequency coupling with the controlled structure, producing a dynamic vibration absorption effect across a wider and lower frequency range. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 A schematic diagram of the overall structure of the spiral acoustic black hole structure provided in Example 1;

[0019] Figure 2 A side view of the acoustic black hole slab provided for Example 1;

[0020] Figure 3 Schematic diagram of the installation of the spiral acoustic black hole structure provided in Example 1 on the controlled structure;

[0021] Figure 4 A side view of the spiral acoustic black hole structure provided in Example 1 being installed on a controlled structure;

[0022] Figure 5 A graph showing the relationship between the vertical spacing between the magnet device of the spiral acoustic black hole structure provided in Example 1 and the interacting magnet device;

[0023] Figure 6 3 is a comparison diagram of the vibration characteristics of the coupling structure of the spiral acoustic black hole structure and the controlled structure in Example 1, the coupling structure of the spiral acoustic black hole structure and the controlled structure without additional magnets, and the controlled structure itself.

[0024] In the figure: 100, spiral acoustic black hole structure; 1, acoustic black hole body; 101, acoustic black hole slat; 102, first slat segment; 103, second slat segment; 104, wedge surface; 105, plane; 2, first magnet device; 3, second magnet device; 4, controlled structure; 5, connecting column; 6, damping member. DETAILED DESCRIPTION

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0026] The purpose of the present invention is to provide a spiral acoustic black hole structure and an acoustic black hole vibration reduction device to solve the problems existing in the above-mentioned prior art, which can achieve low-frequency and broadband vibration reduction, extend the service life, and help save the design space of the acoustic black hole.

[0027] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] Example 1

[0029] like Figures 1 to 6As shown, this embodiment provides a spiral acoustic black hole structure 100, including at least one spiral acoustic black hole body 1, at least one first magnet device 2 and at least one second magnet device 3, each acoustic black hole body 1 is used to connect with a controlled structure 4; each acoustic black hole body 1 is connected to at least one first magnet device 2, and the controlled structure 4 is connected to at least one second magnet device 3, and the magnetic force between each first magnet device 2 and the second magnet device 3 or the adjacent second magnet device 3 can provide support for each acoustic black hole body 1 along a first direction, and the first direction is a direction opposite to the gravity direction of each acoustic black hole body 1. The acoustic black hole body 1 is used to absorb and dissipate the vibration energy on the controlled structure 4. The magnetic force between the first acoustic magnet device 2 and the second magnet device 3 or the first magnet device 2 and the corresponding adjacent first magnet device 2 can offset the gravitational effect of the acoustic black hole body 1, provide support for the acoustic black hole body 1, and improve the stiffness of the acoustic black hole body 1, thereby improving the robustness of the acoustic black hole body 1, preventing the acoustic black hole body 1 from sagging under the action of gravity, and preventing the acoustic black hole body 1 from contacting and colliding with the controlled structure 4, which can improve the vibration reduction effect and extend the service life. At the same time, during the vibration process, the spacing between the interacting magnet devices will change, resulting in a change in the magnetic force between the magnet devices, which can make the structure have the characteristics of variable stiffness, can resonate with structures of multiple natural frequencies, and achieve low-frequency and broadband vibration reduction. Since the magnet devices do not contact each other, stiffness degradation is not likely to occur, so the stability is stronger and the service life is longer. The acoustic black hole body 1 is set in a spiral shape, which is beneficial to saving the design space of the acoustic black hole, and makes the fundamental frequency design of the acoustic black hole lower and the modal density higher, thereby enhancing the low-frequency modal coupling, making the acoustic black hole effect more likely to occur, and having a good low-frequency coupling effect with the controlled structure 4, and can produce a dynamic vibration absorption effect in a wider and lower frequency domain.

[0030] In some specific embodiments, at least N acoustic black hole bodies 1 are arranged in sequence along the vertical direction on the same side of the controlled structure 4, N≥2 and N is an integer, and the direction of the resultant magnetic force between the first magnet device 2 of each acoustic black hole body 1 and the first magnet devices 2 of all other acoustic black hole bodies 1 and all second magnet devices 3 is opposite to the first direction.

[0031] In some specific embodiments, the acoustic black hole body 1 close to the controlled structure 4 is the first acoustic black hole body 1, and the end of the first magnet device 2 on the first acoustic black hole body 1 close to the controlled structure 4 has the same polarity as the end of the second magnet device 3 on the controlled structure 4 close to the first acoustic black hole body 1, and the end of the first magnet device 2 on the Nth acoustic black hole body 1 close to the controlled structure 4 has the same polarity as the end of the first magnet device 2 on the N-1th acoustic black hole body 1 away from the controlled structure 4.

[0032] In some specific embodiments, the first magnet device 2 on the first acoustic black hole body 1 corresponds one-to-one with the second magnet device 3 on the controlled structure 4, and the first magnet devices 2 on two adjacent acoustic black hole bodies 1 correspond one-to-one. Each first magnet device 2 on each acoustic black hole body 1 can form a nonlinear magnetic coupling with the corresponding first magnet device 2 on the adjacent acoustic black hole body 1, and each second magnet device 3 can form a nonlinear magnetic coupling with the corresponding first magnet device 2 on the adjacent acoustic black hole body 1. By allowing the first magnet device 2 and the second magnet device 3, and the first magnet device 2 and the adjacent first magnet device 2 to interact and form nonlinear magnetic coupling, the low-frequency action band of the acoustic black hole is broadened, thereby improving the vibration reduction effect on low-frequency vibrations.

[0033] In some specific embodiments, at least one connecting column 5 is further included. Each acoustic black hole body 1 is sleeved outside a connecting column 5 and fixedly connected to the corresponding connecting column 5. At least one acoustic black hole body 1 is sleeved on each connecting column 5, and each connecting column 5 is fixedly connected to the controlled structure 4.

[0034] In some specific embodiments, each acoustic black hole body 1 includes at least one acoustic black hole slat 101, which is formed by all acoustic black hole slats 101 being spirally curled around a common axis and in the same direction. The inner end of each acoustic black hole slat 101 is fixedly connected to a connecting post 5, and the outer end of each acoustic black hole slat 101 is provided with at least one first magnet device 2. The connecting post 5 and the magnet device of this embodiment can respectively support the inner and outer ends of the acoustic black hole slat 101, thereby significantly improving the overall rigidity of the acoustic black hole body 1 with a relatively simple structure.

[0035] In some specific embodiments, each acoustic black hole slab 101 includes a first slab segment 102 and a second slab segment 103, each of which is a variable thickness segment. When each acoustic black hole slab 101 is fully deployed, the thickness of each first slab segment 102 gradually decreases from one end proximal to the second slab segment 103 to the other end. Each second slab segment 103 can be fixedly connected to a corresponding connecting column 5. The thinnest end of the acoustic black hole slab 101 is the head end of the acoustic black hole body 1, and the thickest end of the acoustic black hole slab 101 is the tail end of the acoustic black hole body 1. At least one first magnet device 2 is disposed at the head end of the acoustic black hole body 1. In an ABH, as the thickness of the structure decreases, the group velocity and phase velocity of the bending wave also decrease. Theoretically, when the thickness of the ABH tip is zero, all vibration energy is concentrated at the tip, and there is no reflection. The spiral acoustic black hole structure 100 of this embodiment itself has a variable thickness region, and the wave propagation speed gradually decreases as the thickness decreases. The vibration amplitude is gathered and consumed at the thinnest position of the spiral acoustic black hole structure 100.

[0036] In some specific embodiments, when each acoustic black hole slat 101 is fully expanded, the thickness of each first slat segment 102 decreases in a power function from one end close to the second slat segment 103 to the other end, which is beneficial to improving the modal density.

[0037] In some specific embodiments, at least one damping member 6 is further included, and at least one damping member 6 is connected to each first slat segment 102. The damping member 6 is used to dissipate vibration energy. Because the vibration amplitude of the controlled structure 4 is concentrated at the thinnest location of the spiral acoustic black hole structure 100, the vibration reduction effect can be improved by disposing the damping member 6 on the first slat segment 102.

[0038] In some specific embodiments, two side surfaces of each first strip segment 102 in the thickness direction are a plane surface 105 and a wedge surface 104 , respectively. At least one damping member 6 is bonded to each plane surface 105 .

[0039] In some specific embodiments, each acoustic black hole slat 101 is a slat having a one-dimensional acoustic black hole effect. The damping member 6 is a strip-shaped damping structure with uniform thickness, which is arranged on the plane 105 of the acoustic black hole slat 101 and spirally curled along the acoustic black hole slat 101. The width of the damping member 6 is the same as the width of the acoustic black hole slat 101. As a preferred embodiment, the damping member 6 is a 3M damping plate, and the first magnet device 2 and the second magnet device 3 include at least one N35 neodymium iron boron magnet. The first magnet device 2 is bonded to the acoustic black hole body 1, and the second magnet device 3 is bonded to the controlled structure 4. The connecting column 5 is fixed to the surface of the controlled structure 4 by gluing or welding.

[0040] In some embodiments, the thickness of the first strip segment 102 is expressed as y=a1+εx m Where y represents the thickness variation of the first slat segment 102; ε represents a coefficient; x represents the distance from a point on the plane 105 of each first slat segment 102 to the smaller end point on the corresponding plane 105; m is a constant, and m ≥ 2; a1 represents the minimum thickness of the first slat segment 102. The thickness variation h(s) curve of the first slat segment 102 is:

[0041]

[0042] H max is the maximum thickness of the first strip segment 102, H min is the minimum thickness of the first strip segment 102, s total is the total length of the first strip segment 102 , s represents the distance from a point on the plane 105 of each first strip segment 102 to the corresponding small end point on the plane 105 , and the small end point on the plane 105 is located at the small end of the corresponding first strip segment 102 .

[0043] It should be noted that the setting position of the first magnet device 2 of this embodiment is not limited to the outer end of the acoustic black hole slat 101. The setting position and number of the first magnet device 2 can be adjusted according to the stiffness requirements of the spiral acoustic black hole structure 100.

[0044] The acoustic black hole body 1 and the first magnet device 2 of this embodiment are attached to the controlled structure 4 as a substructure. The overall structure acts as a dynamic vibration absorber to vibrate with the controlled structure 4 and consume the vibration energy of the controlled structure 4. Therefore, the spiral acoustic black hole structure 100 of this embodiment combines the vibration reduction principles of traditional dynamic vibration absorbers (DVA) and acoustic black holes (ABH), and has a good vibration reduction effect. Figure 6 This is a comparison diagram of the vibration characteristics of the coupling structure of the spiral acoustic black hole structure 100 and the controlled structure 4 (controlled plate + MSABH) of this embodiment, the coupling structure of the spiral acoustic black hole without additional magnets and the controlled structure 4 (controlled plate + SABH), and the controlled structure 4 itself (controlled plate), wherein the vertical axis is the acceleration response signal of the measuring point on the controlled structure 4. After the controlled structure 4 is coupled with the spiral acoustic black hole structure 100 of this embodiment, the acceleration response signal is significantly lower than that of the other two structures, indicating that the spiral acoustic black hole structure 100 has a good vibration reduction effect.

[0045] Example 2

[0046] This embodiment provides an acoustic black hole vibration reduction device, which is provided with at least one spiral acoustic black hole structure 100 in Example 1.

[0047] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A spiral acoustic black hole structure, characterized by: It includes at least one spiral acoustic black hole body, at least one first magnet device and at least one second magnet device, each of the acoustic black hole bodies is used to connect with a controlled structure; each of the acoustic black hole bodies is connected to at least one first magnet device, and the controlled structure is connected to at least one second magnet device, and the magnetic force between each of the first magnet devices and the second magnet device or the adjacent second magnet device can provide support for each of the acoustic black hole bodies along a first direction, and the first direction is the direction opposite to the gravity direction of each of the acoustic black hole bodies.

2. The spiral acoustic black hole structure according to claim 1, characterized in that: At least N acoustic black hole bodies are arranged in sequence along the vertical direction on the same side of the controlled structure, N≥2 and N is an integer, and the direction of the resultant magnetic force between the first magnet device of each acoustic black hole body and the first magnet devices of all other acoustic black hole bodies and all the second magnet devices is opposite to the first direction.

3. The spiral acoustic black hole structure according to claim 2, characterized in that: The acoustic black hole body close to the controlled structure is the first acoustic black hole body, the end of the first magnet device on the first acoustic black hole body close to the controlled structure and the end of the second magnet device on the controlled structure close to the first acoustic black hole body have the same polarity, the end of the first magnet device on the Nth acoustic black hole body close to the controlled structure and the end of the first magnet device on the N-1th acoustic black hole body away from the controlled structure have the same polarity.

4. The spiral acoustic black hole structure according to claim 3, characterized in that: The first magnet device on the first acoustic black hole body corresponds one-to-one to the second magnet device on the controlled structure, and the first magnet devices on the two adjacent acoustic black hole bodies correspond one-to-one. Each first magnet device on each acoustic black hole body can form a nonlinear magnetic coupling with the corresponding first magnet device on the adjacent acoustic black hole body, and each second magnet device can form a nonlinear magnetic coupling with the corresponding first magnet device on the adjacent acoustic black hole body.

5. The spiral acoustic black hole structure according to claim 1, characterized in that: It also includes at least one connecting column, each of the acoustic black hole bodies is sleeved outside one of the connecting columns and fixedly connected to the corresponding connecting column, each of the connecting columns is sleeved with at least one acoustic black hole body, and each of the connecting columns is fixedly connected to the controlled structure.

6. The spiral acoustic black hole structure according to claim 5, characterized in that: Each of the acoustic black hole bodies includes at least one acoustic black hole slat, and each of the acoustic black hole bodies is formed by all the acoustic black hole slats spirally curled around the same axis and in the same direction; the inner end of each of the acoustic black hole slats is fixedly connected to the connecting column, and the outer end of each of the acoustic black hole slats is provided with at least one of the first magnet devices.

7. The spiral acoustic black hole structure according to claim 6, characterized in that: Each of the acoustic black hole slats includes a first slat segment and a second slat segment arranged in sequence, and each of the first slat segments is a variable thickness segment; when each of the acoustic black hole slats is fully unfolded, the thickness of each of the first slat segments gradually decreases from one end close to the second slat segment to the other end; each of the second slat segments can be fixedly connected to the corresponding connecting column.

8. The spiral acoustic black hole structure according to claim 7, characterized in that: When each of the acoustic black hole slats is fully expanded, the thickness of each of the first slat segments decreases in a power function form from one end close to the second slat segment to the other end.

9. The spiral acoustic black hole structure according to claim 7, characterized in that: It also includes at least one damping member, and each of the first slat segments is connected to at least one of the damping members.

10. An acoustic black hole vibration reduction device, characterized in that: At least one spiral acoustic black hole structure according to any one of claims 1 to 9 is provided.

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