An additional acoustic black hole combined with a hexagonal honeycomb frame vibration absorber structure

Abstract

The application relates to an additional acoustic black hole combined with a hexagonal honeycomb frame vibration absorber structure, which comprises oppositely arranged upper and lower cover plates, a hexagonal honeycomb frame with the top connected with the upper cover plate and the bottom connected with the lower cover plate, and an additional acoustic black hole damping structure embedded in the inner cavity enclosed by the hexagonal honeycomb frame; the hexagonal honeycomb frame is formed by a plurality of hexagonal cell arrays, and the section of a single hexagonal cell along the direction perpendicular to the cover plate is a symmetrical hexagon; the bottom of the additional acoustic black hole damping structure is fixedly connected with the lower cover plate, and the additional acoustic black hole damping structure does not contact the upper cover plate and the hexagonal honeycomb frame. The additional acoustic black hole damping structure is used for absorbing and dissipating low-frequency vibration energy, the hexagonal honeycomb frame is used as a bearing structure and for isolating part of vibration energy, and the effect of vibration reduction and noise reduction can be improved.

Description

Technical Field

[0001] This invention relates to the field of vibration reduction and noise reduction technology, specifically to a vibration absorber and isolator structure combining an additional acoustic black hole with a hexagonal honeycomb frame. Background Technology

[0002] The concept of the Acoustic Black Hole (ABH) effect has opened a new chapter in the research of artificially manipulating the propagation of flexural waves in elastic media and structures. As a novel passive control method, the acoustic black hole controls wave propagation by designing and optimizing the shape of the structure itself. It has the advantages of simple and flexible implementation, small mass, and great potential and broad application prospects in thin-walled structures. Currently, the main way to achieve the acoustic black hole effect by changing the structural impedance is to change the thickness of the structure. Utilizing the propagation characteristics of flexural waves in structures with varying thickness, when the structural thickness decreases in the form of a certain exponential function, the phase velocity and group velocity of the flexural wave also decrease accordingly. Ideally, when the thickness is reduced to zero, the wave velocity at the edge of the structure can be reduced to zero, achieving zero wave reflection. All wave energy is concentrated at the tip of the structure, and through the damping of the structure and the damping materials attached to the structure, energy absorption or vibration reduction and noise reduction are achieved. The attached acoustic black hole structure has the characteristics of low structural frequency and easy installation, and can be easily installed on equipment to effectively solve the low-frequency vibration problem of the equipment.

[0003] In existing technologies, vibration damping structures primarily utilize acoustic black hole structures as vibration isolation devices. These structures are typically placed directly within rigid support structures. This design relies on the acoustic black hole's vibration absorption capacity to absorb vibrations instead of isolating them, thus reducing the transmission of vibration energy between devices. Although used as a vibration isolator, this structure is still essentially a vibration absorber, not a vibration isolator. This is because the rigid support structure surrounding the acoustic black hole does not effectively isolate vibrations along the transmission path, resulting in relatively strong vibration transmission between devices and consequently, low vibration isolation efficiency. Summary of the Invention

[0004] This invention discloses a vibration absorber and isolator structure combining an additional acoustic black hole with a hexagonal honeycomb frame. The additional acoustic black hole structure is embedded inside the honeycomb frame, which can absorb low-frequency vibration energy through the additional acoustic black hole structure, and also utilize the nonlinear characteristics generated by the honeycomb frame during deformation to reduce stiffness. This effectively isolates low-frequency vibrations in the vibration transmission path and plays a role in vibration isolation.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A vibration absorber / isolate structure combining an additional acoustic black hole with a hexagonal honeycomb frame, comprising:

[0007] Cover plate; the cover plate is divided into an upper cover plate and a lower cover plate arranged in parallel;

[0008] Hexagonal honeycomb frame; the hexagonal honeycomb frame is formed by connecting multiple hexagonal cells in an array. The hexagonal honeycomb frame surrounds the edge of the cover plate to form a support body with a hollow interior. The bottom of the hexagonal honeycomb frame is fixedly connected to the lower cover plate, and the top of the hexagonal honeycomb frame is fixedly connected to the upper cover plate. The cross-section formed by cutting a single hexagonal cell along the direction perpendicular to the cover plate is symmetrical hexagonal.

[0009] An additional acoustic black hole vibration reduction structure; the additional acoustic black hole vibration reduction structure is located inside the cavity formed by the hexagonal honeycomb frame, the bottom of the additional acoustic black hole vibration reduction structure is fixedly connected to the lower cover plate, and the additional acoustic black hole vibration reduction structure does not contact the upper cover plate or the hexagonal honeycomb frame.

[0010] Furthermore, the six sides of the symmetrical hexagon are divided into two short cell sides and four long cell sides, and the included angle formed by two adjacent long cell sides is θ, where θ ≤ 120°.

[0011] Furthermore, both the hexagonal honeycomb frame and the cover plate are made of metal.

[0012] Furthermore, the additional acoustic black hole vibration reduction structure is composed of multiple layers of acoustic black hole structures stacked together. The thickness of each acoustic black hole structure is the thickest in the central region, and the thickness decreases from the central region to the edge. Each acoustic black hole structure has a damping material layer bonded to its edge.

[0013] Furthermore, the additional acoustic black hole vibration reduction structure is composed of a one-dimensional acoustic black hole structure and a two-dimensional acoustic black hole structure stacked together.

[0014] Furthermore, the one-dimensional acoustic black hole structure adopts a spiral acoustic black hole structure, and the two-dimensional acoustic black hole structure adopts a circular acoustic black hole structure and / or a rectangular acoustic black hole structure.

[0015] Furthermore, the spiral acoustic black hole structure includes a central region, a strip-shaped acoustic black hole region extending outward from the central region in a spiral, and a damping strip attached to the end of the strip-shaped acoustic black hole region. The central region has the largest thickness and the thickness is the same. A through hole is opened in the central region. The thickness of the strip-shaped acoustic black hole region gradually decreases from the beginning near the central region to the end.

[0016] Furthermore, both the circular acoustic black hole structure and the rectangular acoustic black hole structure include a connecting post, an acoustic black hole portion that covers the outer periphery of the connecting post and forms an integral part with the connecting post, and a first annular portion that is integrally connected to the edge of the acoustic black hole portion. A damping material layer is pasted on the first annular portion to form a second annular portion. The thickness is greatest and the thickness is the same in the area where the connecting post is located. Through holes are opened on the connecting post. The thickness of the acoustic black hole portion decreases exponentially from the adjacent connecting post outwards.

[0017] Furthermore, the rectangular acoustic black hole structure is an eccentric structure, that is: the upper surface of the acoustic black hole part is a first rectangular surface, the lower surface of the connecting column is a second rectangular surface, and a line is drawn between the center of the first rectangular surface and the center of the second rectangular surface, which is not perpendicular to the first rectangular surface.

[0018] Furthermore, the additional acoustic black hole vibration reduction structure is composed of at least two sets of acoustic black hole structures stacked together, each set of acoustic black hole structures being composed of spiral acoustic black hole structures, circular acoustic black hole structures, and rectangular acoustic black hole structures stacked together.

[0019] The vibration absorber / isolation structure designed in this invention not only supports the upper and lower cover plates through the hexagonal honeycomb frame, but also fully utilizes the nonlinear characteristics generated by the deformation of the hexagonal honeycomb frame under load. It can have a large structural stiffness when the deformation is small to meet the load-bearing requirements, and the stiffness can decrease as the load increases to meet the requirements of low-frequency vibration isolation, thereby reducing the natural frequency of the vibration absorber / isolation structure and effectively isolating low-frequency vibrations. In this invention, the additional acoustic black hole vibration reduction structure is set in the inner cavity enclosed by the hexagonal honeycomb frame. The hexagonal honeycomb frame can also protect the additional acoustic black hole vibration reduction structure, avoiding external interference and damage to the additional acoustic black hole vibration reduction structure, which would affect the vibration reduction effect of the structure.

[0020] The vibration absorber / isolated structure designed in this invention is installed on the vibration transmission path of the equipment, with the excitation source acting on the lower cover plate. When vibration energy passes through the vibration absorber / isolated structure of this invention, it can be effectively isolated by the hexagonal honeycomb frame, and the energy is absorbed and dissipated by the additional acoustic black hole vibration reduction structure. This vibration absorber / isolated structure can effectively avoid the drawback of traditional additional dynamic vibration absorbers, which can only work effectively at specific frequencies, by combining the low frequency selectivity of nonlinear structures with the effective energy accumulation and dissipation characteristics of acoustic black hole structures. Thus, it can efficiently exert its advantages in vibration isolation. Attached Figure Description

[0021] Figure 1 This is a specific example diagram of a vibration absorber / isolater structure combining an additional acoustic black hole with a hexagonal honeycomb frame, as provided in this invention.

[0022] Figure 2 for Figure 1 Elevation view of the hexagonal honeycomb frame and structural diagram of a single hexagonal cell;

[0023] Figure 3 for Figure 2 Exploded view of the mid-mounted acoustic black hole vibration reduction structure;

[0024] Figure 4 A schematic diagram of the structure of a circular acoustic black hole;

[0025] Figure 5 A schematic diagram of a rectangular acoustic black hole structure;

[0026] Figure 6 A schematic diagram of a spiral acoustic black hole structure;

[0027] Figure 7 A diagram showing the components of a rectangular acoustic black hole structure.

[0028] Figure 8 A top view of a rectangular acoustic black hole structure;

[0029] Figure 9 for Figure 8 AA section view in the middle;

[0030] Figure 10 for Figure 8 BB cross-section diagram in the middle;

[0031] Figure 11 This is a diagram showing the vibration energy accumulation in the energy-accumulating part of the additional acoustic black hole vibration reduction structure.

[0032] Figure 12 The simulated displacement-load curve is obtained after applying a load to the upper cover plate of one specific example of the vibration absorber and isolator of the present invention.

[0033] Figure label:

[0034] 1. Cover plate; 11. Upper cover plate; 12. Lower cover plate;

[0035] 2. Hexagonal honeycomb border; 21. Short side of cell; 22. Long side of cell;

[0036] 3. Additional acoustic black hole vibration reduction structure; 31. Connecting column; 32. Acoustic black hole section; 321. First rectangular surface; 322. Second rectangular surface; 33. First annular part; 34. Second annular part; 35. Central region; 36. Strip-shaped acoustic black hole region; 37. Damping strip;

[0037] 3A. Circular acoustic black hole structure; 3B. Rectangular acoustic black hole structure; 3C. Spiral acoustic black hole structure. Detailed Implementation

[0038] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0039] This embodiment discloses a vibration absorber / isolation device structure, such as... Figure 1 As shown, an additional acoustic black hole vibration reduction structure 3 is combined with a hexagonal honeycomb frame 2. The hexagonal honeycomb frame 2 is used for vibration isolation, while the additional acoustic black hole vibration reduction structure 3 is used for energy accumulation and dissipation.

[0040] In this embodiment, the vibration absorber / isolate structure consists of a hexagonal honeycomb frame 2 and a cover plate 1 forming a support structure. This support structure is installed between the excitation source and the controlled structure. The cover plate 1 is further divided into an upper cover plate 11 and a lower cover plate 12, which are arranged opposite each other. The hexagonal honeycomb frame 2 is disposed between the upper cover plate 11 and the lower cover plate 12. Figure 1 Taking the rectangular cover plate 1 as an example, four hexagonal honeycomb frames 2 are used to enclose the top edge of the lower cover plate 12, forming a cavity to accommodate the additional acoustic black hole vibration damping structure 3. The additional acoustic black hole vibration damping structure 3 is placed in this cavity. The bottom of the additional acoustic black hole vibration damping structure 3 is fixed to the lower cover plate 12, the bottom of the hexagonal honeycomb frames 2 is fixed to the lower cover plate 12, and the top of the hexagonal honeycomb frames 2 is fixed to the upper cover plate 11. It should be noted that in this embodiment, the top of the additional acoustic black hole vibration damping structure 3 does not contact the upper cover plate 11, and the side of the additional acoustic black hole vibration damping structure 3 does not contact the hexagonal honeycomb frames 2.

[0041] In this embodiment, both the hexagonal honeycomb frame 2 and the cover plate 1 are made of metal, such as aluminum or steel. Metal is easy to process and can meet the load-bearing requirements of general structures. Threaded holes are opened at the bottom and top of the hexagonal honeycomb frame 2, and corresponding threaded holes are also opened on the upper cover plate 11 and lower cover plate 12. Bolts are used to fix the hexagonal honeycomb frame 2 and the cover plate 1.

[0042] The hexagonal honeycomb border 2 structure in this embodiment is as follows: Figure 2As shown, the hexagonal honeycomb frame 2 is formed by multiple hexagonal cells arranged in an array and connected to each other, with each hexagonal cell being a symmetrical hexagon. When installing the hexagonal honeycomb frame 2, it is placed vertically, meaning that each hexagonal honeycomb frame 2 is cut along a direction perpendicular to the cover plate 1, and the cross-section of each hexagonal cell is a symmetrical hexagon. In this embodiment, the hexagonal honeycomb frame 2 is arranged vertically to utilize the nonlinear characteristics generated when the hexagonal frame is compressed in this direction for vibration isolation. If the hexagonal honeycomb frame is arranged horizontally (i.e., the cross-section along the direction parallel to the cover plate is hexagonal), the structure does not have nonlinear characteristics and the structural stiffness is too large to meet the vibration reduction requirements. When the hexagonal honeycomb frame is arranged vertically, the stiffness of the entire vibration absorber structure can be changed, achieving low-frequency vibration isolation. The cross-sectional shape of the hexagonal cell is formed by six sides combining to form a hexagon. This hexagon is divided into regular hexagons and non-regular hexagons, such as... Figure 2 In the hexagonal cell shown, dashed lines represent regular hexagons, and solid lines represent non-regular hexagons. When it's a regular hexagon, the angle between any two adjacent sides is 120°. When it's a non-regular hexagon, as shown... Figure 2 As shown, the two shorter sides are called cell short sides 21, and the four longer sides are called cell long sides 22. The included angle formed by adjacent cell long sides 22 is θ, where θ < 120°. If the hexagonal cells in the hexagonal honeycomb frame 2 are designed with non-regular hexagons, compared with regular hexagons, they have stronger nonlinear properties, meaning the structural stiffness changes more under load. This can significantly reduce the structural stiffness, and the lower stiffness allows the vibration isolation structure to have lower modal frequencies, thus achieving the goal of low-frequency vibration reduction. However, reduced stiffness will affect load-bearing requirements. Therefore, depending on the actual working conditions and load-bearing requirements, a regular hexagonal structural design can also be chosen.

[0043] The additional acoustic black hole vibration reduction structure 3 in this embodiment is composed of multiple layers of acoustic black hole structures stacked together. Taking the common rectangular acoustic black hole structure as an example, rectangular acoustic black hole structures are further divided into symmetrical structures and asymmetrical structures, such as... Figure 5 , Figures 7 to 10 The diagram shows an eccentric rectangular acoustic black hole structure 3B. This asymmetrical structure enriches the modal configuration of the acoustic black hole structure, enhances the dynamic vibration absorption capability of the vibration absorber / isolation structure, and reduces the lowest frequency of the vibration absorber / isolation structure, thereby improving its low-frequency vibration reduction capability. However, if vibration reduction is only applied to a single fixed frequency, the vibration reduction performance of the eccentric structure is inferior to that of the symmetrical structure because, under the same structural mass and natural frequency conditions, the effective modal mass corresponding to the eccentric structure is relatively smaller.

[0044] To demonstrate that the hexagonal honeycomb frame 2 proposed in this invention can achieve a good vibration isolation effect, the inventors use the following specific design example of the vibration absorber / isolation structure for verification and illustration:

[0045] Specific design example: In this design example, the hexagonal cells of the hexagonal honeycomb frame 2 adopt a non-regular hexagonal design, with θ = 60°, and the length of the short side 21 of the cell is 12mm. Both the hexagonal honeycomb frame 2 and the cover plate 1 are made of aluminum. Three eccentric rectangular acoustic black hole structures 3B are stacked to form an additional acoustic black hole vibration reduction structure 3. Among them, as shown... Figure 5 as well as Figures 7 to 10 As shown, the eccentric rectangular acoustic black hole structure 3B includes a connecting post 31 and an eccentric rectangular disk that covers the outer periphery of the side of the connecting post 31 and forms an integral part with the connecting post 31. This eccentric rectangular disk is the acoustic black hole portion 32. Both the connecting post 31 and the acoustic black hole portion 32 are made of metal, such as aluminum or steel; aluminum is used in this design example. In the rectangular acoustic black hole structure 3B, the connecting post 31 is a cuboid with a through hole containing internal threads. The thickness of the area where the connecting post 31 is located is uniform. In the thickness distribution of the entire rectangular acoustic black hole structure 3B (referring to the thickness along the height direction of the connecting post 31), the thickness is greatest at the connecting post 31. The thickness of the acoustic black hole portion 32 decreases exponentially from the connection point on the side of the connecting post 31 outwards. The upper surface of the acoustic black hole section 32 is a first rectangular surface 321, and the lower surface of the connecting column 31 is a second rectangular surface 322. A line is drawn between the center point of the first rectangular surface 321 and the center point of the second rectangular surface 322, but this line is not perpendicular to the first rectangular surface 321. The thinnest edge of the acoustic black hole section 32 is circumferentially connected to the first annular portion 33, which has the smallest thickness in the entire rectangular acoustic black hole structure 3B, and its thickness is uniform throughout. A layer of damping material, using butyl rubber, is adhered to the first annular portion 33 to form the second annular portion 34.

[0046] Continuing from the above explanation, the first annular portion 33 is an extension of the acoustic black hole portion 32. It has the smallest thickness and lowest stiffness, enabling the vibration absorber / isolated structure to have a lower modal frequency and improve low-frequency damping capability. The thickness of the first annular portion 33 is typically 0.3mm to 1mm, and the thickness of the second annular portion 34 is typically 1mm to 3mm. The purpose of attaching the damping layer is to increase the modal damping ratio of the vibration absorber / isolated structure to improve energy dissipation efficiency. If the attached damping layer is too thick, it will increase the edge stiffness of the vibration absorber / isolated structure, thereby increasing the modal frequency and reducing low-frequency damping capability. If it is too thin, it will not effectively improve the modal damping ratio of the system. The radial width of the second annular portion 34 is typically 15mm to 20mm. Because the first annular portion 33 is relatively thin and fragile, if this area is too large, it will easily lead to structural damage. Furthermore, the mass proportion of this area is small, resulting in a lower effective mass. A larger width does not contribute to vibration reduction.

[0047] The exponential expression for the decreasing thickness of the acoustic black hole region 32 is h(w i ) = a i w i n ,i=1,2,3,4, where h(w i ) represents the thickness of the acoustic black hole portion 32, w i i = 1, 2, 3, 4 represent the distances from a point inside the first rectangular face 321 to the corresponding parallel side of the connecting pillar 31, and w i The value range is 0 to w ABHi a i This represents the coefficients corresponding to different regions, where n ≥ 2. For example... Figure 8 As shown, in this design example, w ABH1 =80mm, w ABH2 =70mm, w ABH3 =60mm, w ABH4 =35mm, the maximum thickness of the acoustic black hole section 32 is 10mm and the minimum thickness is 1mm. In this design example, three eccentric rectangular acoustic black hole structures 3B are stacked. The three eccentric rectangular acoustic black hole structures 3B are connected by their respective connecting columns 31. Bolts are used to pass through the through holes on the connecting columns 31 to fix the additional acoustic black hole vibration damping structure 3 formed by the stacking to the lower cover plate 12. The additional acoustic black hole vibration damping structure 3 and the lower cover plate 12 are connected in a detachable manner, which is convenient for replacement to adapt to various different working conditions.

[0048] Based on the vibration absorber structure formed by the above design example, by applying a load to the upper cover plate 11 and fixing and constraining the lower cover plate 12 through simulation, the following can be obtained: Figure 12 The displacement-load curve of the upper cover plate 11 is shown. The displacement-load curve reflects the stiffness variation of the hexagonal honeycomb frame 2. Figure 12As shown in the displacement-load curve, it is not a linear curve. After a certain load is applied, the structural stiffness gradually decreases, reaching zero or even negative stiffness when the load reaches a certain level. The goal of vibration damper design is to achieve low structural stiffness while meeting load-bearing requirements. Low stiffness allows the isolation structure to have lower modal frequencies, achieving low-frequency vibration reduction, while meeting load-bearing requirements necessitates higher structural stiffness—a contradiction. The nonlinear structural design of this invention resolves this contradiction, providing high structural stiffness when deformation is small, thus meeting load-bearing requirements. As the load increases, the structural stiffness gradually decreases, satisfying the need for low-frequency vibration isolation.

[0049] After installing the above-mentioned vibration absorber and isolator structure, the transmission rate between structural components is theoretically derived. Where s is the ratio of the excitation frequency to the structure's natural frequency, and ζ is the structural modal damping ratio, when When η < 1, it indicates that the vibration between the vibration absorber and isolator structures is reduced, and the vibration isolation system can effectively isolate vibrations. Therefore, the lower the natural frequency of the vibration isolation system, the longer the effective vibration isolation bandwidth. Thus, once the equipment mass is determined, it is crucial to select a vibration isolator that meets its load-bearing requirements and has low structural stiffness. The nonlinear support structure of this invention exhibits high stiffness under low loads and low stiffness under high loads, thus meeting load-bearing requirements while possessing a low structural frequency to effectively broaden the vibration isolation bandwidth, making it a superior structure for vibration isolators. By designing the geometric parameters of the vibration absorber and isolator structure and changing the materials, it is possible to design result curves with the same properties but different values, enabling the vibration absorber and isolator structure to have greater load-bearing capacity and better vibration isolation effect.

[0050] The vibration absorber structure designed in this invention applies the excitation source to the lower cover plate 12. After the excitation is transmitted from the lower cover plate 12, it is transmitted to the additional acoustic black hole vibration reduction structure 3, such as... Figure 11 As shown, the vibrational energy is transferred to the thinner part of the acoustic black hole structure's edge through the wave-converging effect of the acoustic black hole structure, and then dissipated by the damping material. On the other hand, the vibrational energy is transferred to the upper cover plate 11 through the hexagonal honeycomb frame 2. The design of the hexagonal honeycomb frame 2 results in lower stiffness, thus reducing its natural frequency. For the vibration isolation system, its effective isolation frequency is half of its natural frequency. When the vibration frequency is greater than the effective isolation frequency, the transmissibility can be reduced to less than 1 to achieve the purpose of vibration reduction. Therefore, the natural frequency of the vibration isolation system should be reduced as much as possible.

[0051] As a further optimization design of the additional acoustic black hole vibration reduction structure 3 of the present invention, such as Figure 3As shown, the additional acoustic black hole vibration reduction structure 3 can be composed of a stack of one-dimensional acoustic black hole structures and two-dimensional acoustic black hole structures. The two-dimensional acoustic black hole structure can be constructed as follows: Figure 3 The circular acoustic black hole structure 3A shown, or using a method such as Figure 5 The rectangular acoustic black hole structure 3B shown; one-dimensional acoustic black hole structures can be constructed using, for example... Figure 6 The spiral acoustic black hole structure 3C is shown. The circular acoustic black hole structure 3A is similar in structure to the rectangular acoustic black hole structure 3B described above, also consisting of a connecting column 31, an acoustic black hole portion 32 covering the side of the connecting column 31, a first annular portion 33, and a second annular portion 34. However, the connecting column 31 is cylindrical here, and the acoustic black hole portion 32 is a circular disk-shaped structure with decreasing thickness exponent. Other details can be found in the description of the rectangular acoustic black hole structure 3B above. The spiral acoustic black hole structure 3C is a beam-shaped acoustic black hole structure, such as... Figure 6 As shown, it includes a Z-shaped central region 35, a spirally coiled strip-shaped acoustic black hole region 36 extending outward from the central region 35, and a damping strip 37 attached to the end of the strip-shaped acoustic black hole region 36. The central region 35 has the greatest and uniform thickness, and has through holes with internal threads. The thickness of the strip-shaped acoustic black hole region 36 gradually decreases from near the central region 35 to its end.

[0052] In the above-mentioned design example for effect verification, for the sake of structural design simplification, only the eccentric rectangular acoustic black hole structure 3B was used for stacking to form the additional acoustic black hole vibration reduction structure 3. In actual engineering design, the spiral acoustic black hole structure 3C, the circular acoustic black hole structure 3A, and the rectangular acoustic black hole structure 3B can be combined in any stacking order to form a set of acoustic black hole structures, and then multiple sets of acoustic black hole structures can be stacked in multiple layers. When forming a single set of acoustic black hole structures, only one of the circular acoustic black hole structure 3A and the rectangular acoustic black hole structure 3B can be selected, or both can be used. If both are used, it is preferable that the rectangular acoustic black hole structure 3B adopts an eccentric structural design, while the circular acoustic black hole structure 3A adopts a non-eccentric structural design.

[0053] Combining various acoustic black hole structures of different shapes can create an optimal vibration reduction structure by leveraging the characteristics of each shape. The spiral acoustic black hole structure 3C, as a one-dimensional acoustic black hole structure, is designed in a spiral shape to extend the length of the acoustic black hole portion within a limited space, resulting in a lower frequency vibration absorber / isolated structure, which is advantageous for low-frequency vibration reduction. However, its drawback is a smaller modal effective mass and lower vibration reduction efficiency. The rectangular acoustic black hole structure 3B and the circular acoustic black hole structure 3A, as two-dimensional acoustic black hole structures, have a larger modal effective mass compared to the spiral acoustic black hole structure 3C. However, their drawback is that, within the same installation space, the modal frequency of their plate-like structure is relatively high. Achieving a lower modal frequency would require either an excessively large structural size or an excessively thin structural thickness, both of which are unfavorable for use. Compared to the symmetrical rectangular acoustic black hole, the eccentric rectangular acoustic black hole structure 3B, with its eccentric design, transforms the symmetrical modes of the vibration absorber / isolate structure at the same frequency into modes at two different frequencies. This results in a richer modality and higher modal density, increasing the probability of coupling between the vibration absorber / isolate structure and the excitation frequency, thereby enhancing dynamic vibration absorption. Simultaneously, the eccentric design lowers the frequency of the vibration absorber / isolate structure without significantly reducing its effective modal mass, which is more beneficial for low-frequency vibration reduction. Therefore, combining acoustic black hole structures of various shapes can integrate their respective advantages and compensate for their shortcomings, thereby improving the vibration absorption efficiency of the additional acoustic black hole vibration reduction structure 3B.

[0054] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A vibration absorber / isolate structure combining an additional acoustic black hole with a hexagonal honeycomb frame, characterized in that, include: Cover plate; the cover plate is divided into an upper cover plate and a lower cover plate arranged in parallel; Hexagonal honeycomb frame; the hexagonal honeycomb frame is formed by connecting multiple hexagonal cells in an array. The hexagonal honeycomb frame surrounds the edge of the cover plate to form a support body with a hollow interior. The bottom of the hexagonal honeycomb frame is fixedly connected to the lower cover plate, and the top of the hexagonal honeycomb frame is fixedly connected to the upper cover plate. The cross-section formed by cutting a single hexagonal cell along the direction perpendicular to the cover plate is symmetrical hexagonal. An additional acoustic black hole vibration reduction structure; the additional acoustic black hole vibration reduction structure is located inside the cavity formed by the hexagonal honeycomb frame, the bottom of the additional acoustic black hole vibration reduction structure is fixedly connected to the lower cover plate, and the additional acoustic black hole vibration reduction structure does not contact the upper cover plate or the hexagonal honeycomb frame.

2. The vibration absorber / isolate structure combining an additional acoustic black hole with a hexagonal honeycomb frame according to claim 1, characterized in that: The symmetrical hexagon has six sides divided into two short cell sides and four long cell sides. The included angle formed by two adjacent long cell sides is... θ , θ ≤120°.

3. The vibration absorber / isolate structure combining an additional acoustic black hole with a hexagonal honeycomb frame according to claim 1, characterized in that: The hexagonal honeycomb frame and cover plate are both made of metal.

4. The vibration absorber / isolate structure combining an additional acoustic black hole with a hexagonal honeycomb frame according to claim 1, characterized in that: The additional acoustic black hole vibration reduction structure is composed of multiple layers of acoustic black hole structures. The thickness of each acoustic black hole structure is the thickest in the central region, and the thickness decreases from the central region to the edge. The edge of each acoustic black hole structure is bonded with a damping material layer.

5. The vibration absorber / isolate structure combining an additional acoustic black hole with a hexagonal honeycomb frame according to claim 4, characterized in that: The additional acoustic black hole vibration reduction structure is composed of a one-dimensional acoustic black hole structure and a two-dimensional acoustic black hole structure stacked together.

6. The vibration absorber / isolate structure combining an additional acoustic black hole with a hexagonal honeycomb frame according to claim 5, characterized in that: The one-dimensional acoustic black hole structure adopts a spiral acoustic black hole structure, while the two-dimensional acoustic black hole structure adopts a circular acoustic black hole structure and / or a rectangular acoustic black hole structure.

7. The vibration absorber / isolate structure combining an additional acoustic black hole with a hexagonal honeycomb frame according to claim 6, characterized in that: The spiral acoustic black hole structure includes a central region, a strip-shaped acoustic black hole region extending outward from the central region in a spiral, and a damping strip attached to the end of the strip-shaped acoustic black hole region. The central region has the largest thickness and the thickness is the same. A through hole is opened in the central region. The thickness of the strip-shaped acoustic black hole region gradually decreases from the beginning near the central region to the end.

8. The vibration absorber / isolate structure combining an additional acoustic black hole with a hexagonal honeycomb frame according to claim 6, characterized in that: Both the circular and rectangular acoustic black hole structures include a connecting post, an acoustic black hole portion that covers the outer periphery of the connecting post and forms an integral part with the connecting post, and a first annular portion that is integral with the edge of the acoustic black hole portion. A damping material layer is pasted on the first annular portion to form a second annular portion. The thickness is greatest and uniform in the area where the connecting post is located. Through holes are opened on the connecting post. The thickness of the acoustic black hole portion decreases exponentially from the adjacent connecting post outwards.

9. The vibration absorber / isolate structure combining an additional acoustic black hole with a hexagonal honeycomb frame according to claim 8, characterized in that: The rectangular acoustic black hole structure is an eccentric structure, that is: the upper surface of the acoustic black hole part is a first rectangular surface, the lower surface of the connecting column is a second rectangular surface, and a line is drawn between the center of the first rectangular surface and the center of the second rectangular surface, which is not perpendicular to the first rectangular surface.

10. A vibration absorber / isolate structure combining an additional acoustic black hole with a hexagonal honeycomb frame according to claim 6 or 9, characterized in that: The additional acoustic black hole vibration reduction structure is composed of at least two sets of acoustic black hole structures stacked together. Each set of acoustic black hole structures is composed of spiral acoustic black hole structures, circular acoustic black hole structures, and rectangular acoustic black hole structures stacked together.

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