Additional acoustic black hole and hexagonal honeycomb frame combined vibration absorption and isolation device structure

Abstract

The invention relates to a vibration absorption and isolation device structure with an additional acoustic black hole combined with a hexagonal honeycomb frame. The vibration absorption and isolation device structure comprises an upper cover plate, a lower cover plate, the hexagonal honeycomb frame and an additional acoustic black hole vibration reduction structure, wherein the upper cover plate and the lower cover plate are oppositely arranged; the bottom of the hexagonal honeycomb frame is connected with the lower cover plate while the top of the hexagonal honeycomb frame is connected with the upper cover plate; the hexagonal honeycomb frame is formed by a plurality of hexagonal cell arrays, and the section formed by sectioning a single hexagonal cell along the direction perpendicular to the cover plate is in a symmetrical hexagon shape; the bottom of the additional acoustic black hole vibration reduction structure is fixedly connected with the lower cover plate, and the additional acoustic black hole vibration reduction structure is not in contact with the upper cover plate and the hexagonal honeycomb frame. Low-frequency vibration energy is absorbed and dissipated through the additional acoustic black hole vibration reduction structure, the effects of bearing the structure and isolating a part of vibration energy are achieved through the hexagonal honeycomb frame, and the vibration reduction and noise reduction effects can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of vibration reduction and noise reduction, and in particular to a vibration absorbing and isolating device structure of an attached acoustic black hole combined with a hexagonal honeycomb frame. Background Art

[0002] The concept of the acoustic black hole (ABH) effect has opened a new chapter in the study of artificial control of the propagation of bending waves in elastic media and structures. As a new passive control method, the acoustic black hole controls the propagation of waves by designing and optimizing the shape of the structure itself. It has the advantages of simple and flexible implementation and low mass, and has great potential and broad application prospects in thin-walled structures. At present, the main way to change the structural impedance to achieve the acoustic black hole effect is to change the thickness of the structure. Utilizing the propagation characteristics of bending waves in variable thickness structures, when the thickness of the structure decreases in the form of a certain exponential function, the phase velocity and group velocity of the bending 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 reflection of the wave, and concentrating all the wave energy at the tip of the structure. Through the damping of the structure and the damping material attached to the structure, the purpose of energy absorption or vibration reduction and noise reduction is achieved. The attached acoustic black hole structure has the characteristics of low structural frequency and easy installation. It can be easily installed on the equipment and effectively solve the low-frequency vibration problem of the equipment.

[0003] In the prior art, in the design of vibration reduction structures, the acoustic black hole structure is mainly used as a vibration isolation structure. The acoustic black hole structure is usually placed directly inside a support structure with greater rigidity. The vibration reduction structure designed in this way uses the vibration absorption capacity of the acoustic black hole structure to replace vibration isolation, thereby reducing the transmission of vibration energy between devices. Although it is used as a vibration isolator, the vibration reduction structure itself is still a vibration absorber, not a vibration isolator. This is because in this vibration reduction structure, a rigid support structure is used around the acoustic black hole structure, which does not have a vibration isolation effect on the vibration transmission path, so that the vibration transmission between devices is still strong, resulting in a low vibration isolation efficiency of the vibration reduction structure. Summary of the invention

[0004] The present invention discloses a vibration absorber structure of an attached acoustic black hole combined with a hexagonal honeycomb frame. The attached acoustic black hole structure is embedded in the honeycomb frame, which can not only absorb low-frequency vibration energy through the attached acoustic black hole structure, but also utilize the nonlinear characteristics of the honeycomb frame during the deformation process to achieve the purpose of reducing stiffness, effectively isolate low-frequency vibrations on the vibration transmission path, and play a role in vibration isolation.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] An attached acoustic black hole combined with a hexagonal honeycomb frame vibration absorber structure, comprising:

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

[0008] A hexagonal honeycomb frame; the hexagonal honeycomb frame is formed by connecting a plurality of hexagonal cells in an array, the hexagonal honeycomb frame is enclosed along the edge of the cover plate to form a support body with a cavity inside, the bottom of the hexagonal honeycomb frame is fixedly connected to the lower cover plate, the top of the hexagonal honeycomb frame is fixedly connected to the upper cover plate, and the cross section formed by cutting a single hexagonal cell in a direction perpendicular to the cover plate is a symmetrical hexagon;

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

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

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

[0012] Furthermore, the additional acoustic black hole vibration reduction structure is formed by stacking multiple layers of acoustic black hole structures, each layer of the acoustic black hole structure is thickest in the central area, and the thickness decreases from the central area to the edge, and a damping material layer is bonded to the edge of each layer of the acoustic black hole structure.

[0013] Furthermore, the additional acoustic black hole vibration reduction structure is formed by stacking a one-dimensional acoustic black hole structure and a two-dimensional acoustic black hole structure.

[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 area, a strip acoustic black hole area extending outward from the central area and formed by spirally winding, and a damping strip pasted to the end of the strip acoustic black hole area. The central area has the largest thickness and the same thickness. A through hole is opened in the central area, and the thickness of the strip acoustic black hole area gradually decreases from the beginning near the central area to the end.

[0016] Furthermore, the circular acoustic black hole structure and the rectangular acoustic black hole structure both include a connecting column, an acoustic black hole part wrapped around the outer circumference of the connecting column and formed as an integral whole with the connecting column, and a first annular part connected to the edge of the acoustic black hole part, a damping material layer is adhered to the first annular part to form a second annular part, the thickness of the area where the connecting column is located is the largest and the thickness is the same, a through hole is opened on the connecting column, and the thickness of the acoustic black hole part decreases exponentially from the adjacent connecting column to the outside.

[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 connected between the center of the first rectangular surface and the center of the second rectangular surface, and the line is not perpendicular to the first rectangular surface.

[0018] Furthermore, the additional acoustic black hole vibration reduction structure is formed by stacking at least two groups of acoustic black hole structures, and each group of acoustic black hole structures is formed by stacking a spiral acoustic black hole structure, a circular acoustic black hole structure, and a rectangular acoustic black hole structure.

[0019] The vibration absorber and isolator structure designed in the present invention can not only support the upper and lower cover plates through the hexagonal honeycomb frame, but also make full use of the nonlinear characteristics of the hexagonal honeycomb frame during the deformation process after bearing the load. It can have a larger structural stiffness when the deformation is small to meet the load-bearing requirements, and can reduce the stiffness as the load increases to meet the needs of low-frequency vibration isolation, reduce the natural frequency of the vibration absorber and isolator structure, and effectively isolate low-frequency vibrations. The present invention arranges the additional acoustic black hole vibration reduction structure in the inner cavity enclosed by the hexagonal honeycomb frame, and the hexagonal honeycomb frame can also protect the additional acoustic black hole vibration reduction structure, thereby preventing the outside world from interfering with and damaging the additional acoustic black hole vibration reduction structure and affecting the vibration reduction effect of the vibration reduction structure.

[0020] The vibration absorber and isolator structure designed by the present invention is installed on the transmission path of the equipment vibration, so that the excitation source acts on the lower cover plate. When the vibration energy passes through the vibration absorber and isolator structure of the present invention, it can be effectively isolated through the hexagonal honeycomb frame, and the energy can be absorbed and dissipated through the attached acoustic black hole vibration reduction structure. The vibration absorber and isolator structure can effectively avoid the disadvantage that the traditional attached dynamic vibration absorber can only work effectively at a specific frequency by combining the low selectivity of the nonlinear structure to the frequency and the effective energy gathering and dissipation characteristics of the acoustic black hole structure, thereby effectively exerting its advantages in the vibration isolation of the vibration absorber and isolator structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A specific example diagram of a vibration absorber structure of an attached acoustic black hole combined with a hexagonal honeycomb frame provided by the present invention;

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

[0023] Figure 3 for Figure 2 An exploded view of the attached acoustic black hole vibration reduction structure;

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

[0025] Figure 5 This is a schematic diagram of the rectangular acoustic black hole structure;

[0026] Figure 6 This is a schematic diagram of the spiral acoustic black hole structure;

[0027] Figure 7 A labeled diagram of the various components of the rectangular acoustic black hole structure;

[0028] Figure 8 This is a top view of the rectangular acoustic black hole structure;

[0029] Fig. 9 for Figure 8 AA section view in;

[0030] Fig.10 for Figure 8 BB section diagram in;

[0031] Fig.11 It is a vibration energy gathering diagram of the energy gathering part in the attached acoustic black hole vibration reduction structure;

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

[0033] Reference numerals:

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

[0035] 2. Hexagonal honeycomb frame; 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 part; 321. First rectangular surface; 322. Second rectangular surface; 33. First annular part; 34. Second annular part; 35. Central area; 36. Strip-shaped acoustic black hole area; 37. Damping strip;

[0037] 3A, circular acoustic black hole structure; 3B, rectangular acoustic black hole structure; 3C, spiral acoustic black hole structure. DETAILED DESCRIPTION

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

[0039] This embodiment discloses a vibration absorber 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, and the additional acoustic black hole vibration reduction structure 3 is used for energy accumulation and dissipation.

[0040] The vibration absorber structure in this embodiment is composed of a hexagonal honeycomb frame 2 and a cover plate 1 to form a support structure, which is installed between the excitation source and the controlled structure. The cover plate 1 is divided into an upper cover plate 11 and a lower cover plate 12 arranged opposite to each other. The hexagonal honeycomb frame 2 is arranged between the upper cover plate 11 and the lower cover plate 12. Figure 1 Taking the rectangular cover plate 1 shown in the figure as an example, four hexagonal honeycomb frames 2 are used to enclose the top edge of the lower cover plate 12, and a cavity for accommodating the additional acoustic black hole vibration reduction structure 3 is formed inside the enclosure, and the additional acoustic black hole vibration reduction structure 3 is placed in the cavity. The bottom of the additional acoustic black hole vibration reduction structure 3 is fixed on the lower cover plate 12, the bottom of the hexagonal honeycomb frame 2 is fixed on the lower cover plate 12, and the top of the hexagonal honeycomb frame 2 is fixed on the upper cover plate 11. It should be noted that the top of the additional acoustic black hole vibration reduction structure 3 in this embodiment does not contact the upper cover plate 11, and the side of the additional acoustic black hole vibration reduction structure 3 does not contact the hexagonal honeycomb frame 2.

[0041] The hexagonal honeycomb frame 2 and the cover plate 1 in this embodiment are both made of metal, such as aluminum or steel, which is easy to process and can meet the load-bearing requirements of general structures. The bottom and top of the hexagonal honeycomb frame 2 are respectively provided with threaded holes, and the corresponding upper cover plate 11 and lower cover plate 12 are also provided with threaded holes, and the hexagonal honeycomb frame 2 and the cover plate 1 are fixedly connected by bolts.

[0042] The structure of the hexagonal honeycomb frame 2 in this embodiment is as follows Figure 2As shown, the hexagonal honeycomb frame 2 is formed by a plurality of hexagonal cells arranged in an array and connected to each other, and each hexagonal cell is a symmetrical hexagon. When installing the hexagonal honeycomb frame 2, place the hexagonal honeycomb frame 2 upright, that is, 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, with the purpose of utilizing the nonlinear characteristics of the hexagonal frame when it is compressed in this direction for vibration isolation. If the hexagonal honeycomb frame is arranged horizontally (that is, 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, which can play a role in low-frequency vibration isolation. The cross-sectional shape of the hexagonal cell is composed of six sides combined into a hexagon, and the hexagon is divided into a regular hexagon and a non-regular hexagon, such as Figure 2 The dashed lines in the hexagonal cells shown in the figure are regular hexagons, and the solid lines are irregular hexagons. When it is a regular hexagon, the angle between two adjacent sides is 120°. When it is a irregular hexagon, such as 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 angle formed by the adjacent cell long sides 22 is θ, θ < 120°. If the hexagonal cells in the hexagonal honeycomb frame 2 adopt a non-regular hexagonal design, compared with the regular hexagon, it has a stronger nonlinear property, that is, the structural stiffness changes more under load, which can significantly reduce the stiffness of the structure. Low stiffness can make the vibration isolation structure have a lower modal frequency, thereby achieving the goal of low-frequency vibration reduction. However, the reduction in stiffness will affect the load-bearing requirements. Therefore, according to the actual working conditions and load-bearing requirements, a regular hexagonal structure design can also be selected.

[0043] The additional acoustic black hole vibration reduction structure 3 in this embodiment is formed by stacking multiple acoustic black hole structures. Taking the common rectangular acoustic black hole structure as an example, the rectangular acoustic black hole structure is divided into a symmetrical structure and an asymmetrical structure, such as Figure 5 , Figures 7 to 10 The figure shows an eccentric rectangular acoustic black hole structure 3B. The eccentric rectangular acoustic black hole structure 3B is an asymmetric structure. This asymmetric structure can enrich the modal conditions of the acoustic black hole structure, enhance the dynamic vibration absorption capacity of the vibration absorption isolator structure, and also reduce the lowest frequency of the vibration absorption isolator structure to improve the low-frequency vibration reduction capacity of the vibration absorption isolator structure. However, if only a certain fixed frequency is used for vibration reduction, the vibration reduction performance of the eccentric structure is not as good as that of the symmetrical structure, because the modal effective mass corresponding to the eccentric structure is relatively smaller under the same structural mass and the same natural frequency conditions.

[0044] In order to prove that the hexagonal honeycomb frame 2 proposed in the present invention can achieve a good vibration isolation effect, the inventor takes the following specific design example of the vibration absorber structure as an example for verification and explanation:

[0045] Specific design example: In this design example, the hexagonal cell of the hexagonal honeycomb frame 2 adopts a non-regular hexagonal design, θ=60°, the length of the short side 21 of the cell is 12 mm, and the hexagonal honeycomb frame 2 and the cover plate 1 are both 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, Figure 5 as well as Figures 7 to 10 As shown, the eccentric rectangular acoustic black hole structure 3B includes a connecting column 31, an eccentric rectangular disk coated on the outer periphery of the side of the connecting column 31 and formed integrally with the connecting column 31, and the eccentric rectangular disk is the acoustic black hole part 32. The connecting column 31 and the acoustic black hole part 32 are both made of metal materials, such as aluminum or steel, and aluminum is used in this design example. In the rectangular acoustic black hole structure 3B, the connecting column 31 is a rectangular parallelepiped, and a through hole with an internal thread is provided on the connecting column 31. The thickness of the area where the connecting column 31 is located is consistent. In the thickness distribution of the entire rectangular acoustic black hole structure 3B (referring to the thickness along the height direction of the connecting column 31), the thickness at the connecting column 31 is the largest, and the thickness of the acoustic black hole part 32 decreases exponentially from the connection at the side of the connecting column 31 to the outside. The upper surface of the acoustic black hole part 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, and the line is not perpendicular to the first rectangular surface 321. The edge of the acoustic black hole part 32, where the thickness is the thinnest, is connected to the first annular part 33 along the circumferential direction. The thickness of the first annular part 33 is the smallest in the entire rectangular acoustic black hole structure 3B, and the thickness of the first annular part 33 is consistent at all locations. A circle of damping material layer is pasted on the first annular part 33 to form the second annular part 34, and the damping material uses butyl rubber material.

[0046] Continuing with the above description, the first annular portion 33 is an extension of the acoustic black hole portion 32, and has the smallest thickness and lower rigidity, which enables the vibration absorber structure to have a lower modal frequency and improve the low-frequency vibration reduction capability. The thickness of the first annular portion 33 is usually 0.3mm to 1mm, and the thickness of the second annular portion 34 is usually 1mm to 3mm. The purpose of pasting the damping layer is to increase the modal damping ratio of the vibration absorber structure to improve energy consumption efficiency. Pasting the damping layer too thick will increase the edge stiffness of the vibration absorber structure, thereby increasing the modal frequency and reducing the low-frequency vibration reduction capability. If it is too thin, the modal damping ratio of the system cannot be effectively improved. The radial width of the second annular portion 34 is usually 15mm to 20mm. Because the first annular portion 33 is relatively small in thickness and relatively fragile, if this area is too large, it is easy to cause the structure to be damaged and the mass of this area accounts for a small proportion, then the corresponding effective mass is also low, and a larger width does not help with vibration reduction.

[0047] The exponential expression of the decreasing thickness of the acoustic black hole part 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 part 32, w i , i=1,2,3,4 represents the distance from a point in the first rectangular surface 321 to the corresponding parallel side of the connecting column 31, w i The value range is 0~w ABHi , a i Indicates the coefficients corresponding to different regions, n≥2. 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 part 32 is 10mm, and the minimum thickness is 1mm. This design example uses three eccentric rectangular acoustic black hole structures 3B for stacking. The three eccentric rectangular acoustic black hole structures 3B are connected by their respective connecting columns 31. Bolts are passed through the through holes on the connecting columns 31 to fix the additional acoustic black hole vibration reduction structure 3 formed after stacking on the lower cover plate 12. The additional acoustic black hole vibration reduction structure 3 is connected to the lower cover plate 12 in a detachable manner, which is easy to replace to adapt to various working conditions.

[0048] According to the vibration absorber structure formed in the above design example, a load is applied to the upper cover plate 11 by simulation method, and the lower cover plate 12 is fixed and constrained, and the following can be obtained: Fig.12 The displacement-load curve can reflect the change of the stiffness of the hexagonal honeycomb frame 2. Fig.12It can be seen from the displacement load curve shown that the displacement load curve is not a linear curve. After a certain load is applied, the structural stiffness gradually decreases. When the load is applied to a certain extent, the structural stiffness is 0 or even negative stiffness appears. The goal of the vibration absorber structural design is to make the structure have a lower structural stiffness while meeting the load-bearing conditions. Low stiffness can make the vibration isolation structure have a lower modal frequency to achieve the goal of low-frequency vibration reduction, while meeting the load-bearing conditions requires a larger structural stiffness, which is contradictory. The design of the nonlinear structure of the present invention solves this contradiction, so that the structure has a larger structural stiffness when the deformation is small, which can meet the load-bearing conditions. As the load increases, the structural stiffness gradually decreases, meeting the demand for low-frequency vibration isolation.

[0049] After installing the above-mentioned vibration absorber and isolator structure, the transmission rate between the structural equipment is deduced from theory. Where s is the ratio of the excitation frequency to the structural natural frequency, ζ is the structural modal damping ratio, When , η<1, indicating that the vibration between the vibration isolator structures is reduced, and the vibration isolation system can effectively isolate vibrations. Therefore, when the natural frequency of the vibration isolation system is smaller, the effective vibration isolation frequency band is longer. Therefore, when the quality of the equipment is determined, it is very important to select a vibration isolator that can meet its load-bearing requirements and has a smaller structural stiffness. The nonlinear support structure of the present invention can exhibit high stiffness when the load is small, and low stiffness when the load is large. It can meet the load-bearing requirements and have a lower structural frequency to effectively broaden the vibration isolation frequency band. It is a high-quality structure as a vibration isolator. By designing the geometric parameters of the vibration isolator structure and changing the materials, it is possible to design result curves with the same properties but different values, so that the vibration isolator structure can have a greater load-bearing capacity and better vibration isolation effect.

[0050] The vibration absorber structure designed in the present invention applies the excitation source to the lower cover plate 12. When 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 Fig.11 As shown, the vibration energy is transferred to the thinner part of the edge of the acoustic black hole structure through the wave focusing effect of the acoustic black hole structure, and then the vibration energy is dissipated by the damping material; on the other hand, the vibration energy is transferred to the upper cover plate 11 through the hexagonal honeycomb frame 2. The stiffness of the hexagonal honeycomb frame 2 is lowered by designing the hexagonal honeycomb frame 2, thereby reducing its natural frequency. For the vibration isolation system, its effective vibration isolation frequency is 1 / 2 of its natural frequency. When the vibration frequency is greater than the effective vibration isolation frequency, the transmission rate can be made 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, Figure 3As shown, the additional acoustic black hole vibration reduction structure 3 can be formed by stacking a one-dimensional acoustic black hole structure and a two-dimensional acoustic black hole structure. Figure 3 The circular acoustic black hole structure 3A shown in FIG. Figure 5 The rectangular acoustic black hole structure 3B shown in FIG. 3B; the one-dimensional acoustic black hole structure can be adopted as follows Figure 6 The spiral acoustic black hole structure 3C shown. The structure of the circular acoustic black hole structure 3A is similar to the rectangular acoustic black hole structure 3B given above, and is also composed of a connecting column 31, an acoustic black hole part 32 wrapped on the side of the connecting column 31, a first annular part 33 and a second annular part 34, except that the connecting column 31 is a cylindrical structure here, and the acoustic black hole part 32 is a circular disc structure with an exponentially decreasing thickness. For other details, please refer to the above description of the rectangular acoustic black hole structure 3B. 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 area 35, a strip-shaped acoustic black hole area 36 extending outward from the central area 35 and spirally coiled, and a damping strip 37 pasted to the end of the strip-shaped acoustic black hole area 36. The central area 35 has the largest thickness and the same thickness. The central area 35 is provided with a through hole with an internal thread. The thickness of the strip-shaped acoustic black hole area 36 gradually decreases from the vicinity of the central area 35 to the end.

[0052] When the above-mentioned design example is used for effect verification, in order to simplify the structural design, only the eccentric rectangular acoustic black hole structure 3B is stacked 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 group of acoustic black hole structures, and then multiple groups of acoustic black hole structures are used for multi-layer stacking. When forming a single group 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 preferred 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 acoustic black hole structures of various shapes can form an optimal vibration reduction structure by combining the characteristics of acoustic black hole structures of different shapes. The spiral acoustic black hole structure 3C is a one-dimensional acoustic black hole structure. The spiral shape can extend the length of the acoustic black hole part in a limited space, so that the vibration absorber structure has a lower frequency, which is advantageous for low-frequency vibration reduction. However, its disadvantage is that the modal effective mass of the vibration absorber structure is small and the vibration reduction efficiency is low. The rectangular acoustic black hole structure 3B and the circular acoustic black hole structure 3A are two-dimensional acoustic black hole structures. Compared with the spiral acoustic black hole structure 3C, their modal effective mass is larger, but their disadvantage is that in the same installation space, the modal frequency of their plate-like structures is relatively high. To achieve a lower modal frequency, the structure size will be too large or the structure thickness will be too thin, which is not conducive to use. Compared with the symmetrical rectangular acoustic black hole, the eccentric rectangular acoustic black hole structure 3B has an eccentric structural design that makes the symmetrical mode of the vibration absorber structure at the same frequency become modes at two different frequencies, making the modes richer and the modal density higher, which can increase the probability of coupling between the vibration absorber structure and the excitation frequency, thereby strengthening the dynamic vibration absorption effect. At the same time, the eccentric design can reduce the frequency of the vibration absorber structure, and its modal effective mass will not be greatly reduced, which is more conducive to low-frequency vibration reduction. Therefore, the combination of acoustic black hole structures of various shapes can combine their respective advantages and make up for their respective shortcomings, thereby improving the vibration absorption efficiency of the additional acoustic black hole vibration reduction 3 structure.

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

Claims

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

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

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

4. The additional acoustic black hole combined with a hexagonal honeycomb frame vibration absorber structure according to claim 1 is characterized in that: The additional acoustic black hole vibration reduction structure is formed by stacking multiple layers of acoustic black hole structures. The thickness of each layer of acoustic black hole structure is the thickest in the central area, and the thickness decreases from the central area to the edge. A damping material layer is bonded to the edge of each layer of acoustic black hole structure.

5. The additional acoustic black hole combined with a hexagonal honeycomb frame vibration absorber structure according to claim 4 is characterized in that: The additional acoustic black hole vibration reduction structure is formed by stacking a one-dimensional acoustic black hole structure and a two-dimensional acoustic black hole structure.

6. The additional acoustic black hole combined with a hexagonal honeycomb frame vibration absorber structure according to claim 5 is characterized by: 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.

7. The additional acoustic black hole combined with a hexagonal honeycomb frame vibration absorber structure according to claim 6 is characterized by: The spiral acoustic black hole structure includes a central area, a strip acoustic black hole area extending outward from the central area and formed by spirally winding, and a damping strip pasted to the end of the strip acoustic black hole area. The central area has the largest thickness and the same thickness. A through hole is opened in the central area, and the thickness of the strip acoustic black hole area gradually decreases from the beginning near the central area to the end.

8. The additional acoustic black hole combined with a hexagonal honeycomb frame vibration absorber structure according to claim 6 is characterized by: The circular acoustic black hole structure and the rectangular acoustic black hole structure both include a connecting column, an acoustic black hole portion wrapped around the outer circumference of the connecting column and formed as an integral unit with the connecting column, a first annular portion connected to an edge of the acoustic black hole portion, a damping material layer is adhered to the first annular portion to form a second annular portion, the thickness of the region where the connecting column is located is the largest and the thickness is the same, a through hole is provided on the connecting column, and the thickness of the acoustic black hole portion decreases exponentially from the adjacent connecting column outward.

9. The additional acoustic black hole combined with a hexagonal honeycomb frame vibration absorber structure 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 connected between the center of the first rectangular surface and the center of the second rectangular surface, and the line is not perpendicular to the first rectangular surface.

10. The additional acoustic black hole combined with a hexagonal honeycomb frame vibration absorber structure according to claim 6 or 9, characterized in that: The additional acoustic black hole vibration reduction structure is formed by stacking at least two groups of acoustic black hole structures, and each group of acoustic black hole structures is formed by stacking a spiral acoustic black hole structure, a circular acoustic black hole structure, and a rectangular acoustic black hole structure.

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