An acoustic black hole vibration reduction structure

Abstract

This invention discloses an acoustic black hole vibration reduction structure, belonging to the field of vibration reduction and noise reduction technology. Its structure is novel and rational. The spring-type acoustic black hole structure itself has a variable thickness region; the wave propagation speed gradually decreases as the thickness decreases, and the vibration amplitude concentrates at the thinnest point of the spring-type acoustic black hole structure, resulting in vibration energy concentration at the thinnest point. Simultaneously, by placing damping material on the surface of the spring-type acoustic black hole structure, vibration energy dissipation is further achieved. Furthermore, due to the spiral structural design of the spring-type acoustic black hole structure, it breaks the current mindset of designing acoustic black holes in large sizes for low-frequency vibration suppression, saving design space and allowing for extremely low fundamental frequency design. Combined with a high modal density, this enhances low-frequency modal coupling, making the acoustic black hole effect more likely to occur, thereby effectively suppressing extremely low-frequency vibrations.

Description

Technical Field

[0001] This invention relates to the field of vibration reduction and noise reduction technology, and in particular to an acoustic black hole vibration reduction structure. Background Technology

[0002] The acoustic black hole (ABH) effect works by altering the thickness of a structure, leading to changes in its impedance. This alters the phase and group velocities of waves propagating within the structure, causing wave concentration at its tips or weak points. Utilizing the propagation characteristics of bent waves in structures with varying thickness, ideally, when the thickness is reduced to zero, the phase and group velocities of the bent waves also decrease to zero, resulting in zero wave reflection and energy concentration. In actual fabrication, due to truncation, the thickness cannot be reduced to zero, but energy still concentrates in the region of minimum thickness. Therefore, incorporating a small amount of damping material in the energy concentration region can effectively enhance the structural loss factor, absorb energy, and reduce structural vibration.

[0003] Traditional acoustic black hole structures achieve good results in mid-to-high frequency vibration control. However, in low-frequency vibrations below 50Hz, the size of the acoustic black hole structure often needs to be designed to be particularly large. Especially in vibration reduction applications for equipment in aerospace and transportation, traditional large-sized acoustic black hole structures are not only inconvenient to install, but also cannot meet the design requirements for low-frequency vibration reduction. In other words, they are unsuitable for controlling low-frequency vibrations and noise. Therefore, there is an urgent need to find effective ways to reduce the operating frequency of acoustic black hole structures.

[0004] In summary, there is an urgent need in this field for a novel acoustic black hole structure that can solve the problem of low-frequency vibration reduction and noise reduction while saving installation space. Summary of the Invention

[0005] The purpose of this invention is to provide a novel acoustic black hole vibration reduction structure that can solve the problem of low-frequency vibration reduction and noise reduction in structures while saving installation space.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] This invention provides an acoustic black hole vibration reduction structure, comprising:

[0008] The spring-type acoustic black hole structure is made of spirally rolled slats with a one-dimensional acoustic black hole effect, used to absorb and dissipate vibration energy generated at any position on the structure to be damped.

[0009] An installation component is provided at one end of the spring-type acoustic black hole structure for connecting the spring-type acoustic black hole structure to the structure to be vibration-damped.

[0010] Damping material is disposed on the surface of the slats to dissipate vibration energy.

[0011] Optionally, when the slats are fully extended, the thickness decreases exponentially from one end to the other; and the end with the thickest slat is the first end of the spring-type acoustic black hole structure, and the end with the thinnest slat is the last end of the spring-type acoustic black hole structure; the mounting component is disposed at the first end of the spring-type acoustic black hole structure.

[0012] Optionally, the expression for the thickness of the slat is y = a1 + εx m Where y represents the thickness variation of the strip; ε represents a coefficient; x represents the length variation of the strip; m is a constant, and m≥2; a1 represents the thickness value of the thinnest end of the strip.

[0013] Optionally, when the slats are fully unfolded, the lower layer is a plane and the upper layer is a wedge, and the distance between the plane and the wedge is the thickness of the slats.

[0014] Optionally, the damping material is a strip-shaped damping structure with uniform thickness, which is disposed on the wedge surface of the strip and spirally rolled with the strip.

[0015] Optionally, the width of the strip damping structure is the same as the width of the slat.

[0016] Optionally, the damping material is a 3M damping sheet.

[0017] Optionally, the mounting component is a quarter-circular plate of uniform thickness, one end of which is connected to the first end of the spring-type acoustic black hole structure.

[0018] Optionally, the thickness of the quarter-circular plate is the same as the thickness of the first end of the spring-type acoustic black hole structure.

[0019] Optionally, the quarter-circular plate is glued or welded to the front end of the spring-type acoustic black hole structure.

[0020] Optionally, at least one of the mounting component and the strip is made of photosensitive resin.

[0021] The present invention achieves the following technical effects compared to the prior art:

[0022] The acoustic black hole vibration reduction structure proposed in this invention is novel and rational. The spring-type acoustic black hole structure itself has a variable thickness region, and the wave propagation speed gradually decreases as the thickness decreases. The vibration amplitude is concentrated at the thinnest point of the spring-type acoustic black hole structure, resulting in the concentration of vibration energy at the thinnest point. At the same time, by setting damping material on the surface of the spring-type acoustic black hole structure, the dissipation of vibration energy is further achieved. In addition, due to the spiral structure design of the spring-type acoustic black hole structure, it breaks the current mindset of designing acoustic black holes in large sizes for low-frequency vibration suppression, saving design space for acoustic black holes and allowing for extremely low fundamental frequency design of acoustic black holes. Combined with high modal density, it enhances low-frequency modal coupling, making the acoustic black hole effect easier to occur, thereby effectively suppressing extremely low-frequency vibrations. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the overall structure of the acoustic black hole vibration reduction structure disclosed in the embodiments of the present invention;

[0025] Figure 2 This is a front view of the spring-type acoustic black hole structure disclosed in an embodiment of the present invention.

[0026] Figure 3 This is a bottom view of the spring-type acoustic black hole structure disclosed in the embodiments of the present invention;

[0027] Figure 4 This is a schematic diagram of the spring-type acoustic black hole structure disclosed in the embodiments of the present invention when it is in a fully deployed state;

[0028] Figure 5 This is a schematic diagram of the spiral curling principle of the spring-type acoustic black hole structure disclosed in the embodiments of the present invention;

[0029] Figure 6 This is a three-dimensional structural diagram of the spring-type acoustic black hole structure disclosed in the embodiments of the present invention;

[0030] Figure 7 This is a schematic diagram of the installation of the acoustic black hole vibration reduction structure disclosed in the embodiment of the present invention on an aircraft wing;

[0031] Figure 8 This is a partial perspective view of the acoustic black hole vibration reduction structure disclosed in the embodiments of the present invention on an airfoil;

[0032] Figure 9 This is a comparison diagram of the damping characteristics of three cases disclosed in the embodiments of the present invention: wing (without acoustic black hole damping structure), wing with acoustic black hole damping structure, and wing with additional control group structure.

[0033] Figure 10 This is a comparison diagram of the vibration characteristics of a wing (without the acoustic black hole vibration reduction structure), a wing with the acoustic black hole vibration reduction structure, and a wing with an additional control group structure disclosed in the embodiments of the present invention.

[0034] The attached figures are labeled as follows:

[0035] 1. Acoustic black hole vibration reduction structure; 11. Spring-type acoustic black hole structure; 111. Slats; 112. Lower layer; 113. Upper layer; 12. Mounting components; 121. Lower surface; 122. Inner ring; 123. Outer ring; 124. End plate one; 125. End plate two; 13. Damping material;

[0036] 2. Wings. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] One of the objectives of this invention is to provide a novel acoustic black hole vibration reduction structure that can solve the problem of low-frequency vibration reduction and noise reduction in structures while saving installation space.

[0039] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] Example 1

[0041] like Figure 1As shown, this embodiment provides an acoustic black hole vibration reduction structure 1, which includes a spring-type acoustic black hole structure 11, a mounting component 12, and a damping material 13. The spring-type acoustic black hole structure 11 is formed by spirally coiling a slat 111 with a one-dimensional acoustic black hole effect, used to absorb and dissipate vibration energy generated at any position on the structure to be vibration-reduced. Generally, the slat 111 is coiled into a spiral in the form of a standard spiral. The mounting component 12 is disposed at one end of the spring-type acoustic black hole structure 11, used to connect the spring-type acoustic black hole structure 11 to the structure to be vibration-reduced, thereby establishing a connection between the spring-type acoustic black hole structure 11 and the structure to be vibration-reduced. The damping material 13 is disposed on the surface of the slat 111, forming the outermost contour of the spring-type acoustic black hole structure 11, used to further dissipate vibration energy. The above-mentioned acoustic black hole vibration reduction structure 1, combined with the design of the spring spiral structure, compresses the space of the acoustic black hole vibration reduction structure and improves the control efficiency of the acoustic black hole vibration reduction structure for low-frequency vibrations.

[0042] In this embodiment, as Figure 2 , Figure 4 and Figure 6 As shown, when the slat 111 is fully extended, the thickness decreases exponentially from one end to the other; and the thickest end of the slat 111 is the first end of the spring-type acoustic black hole structure 11, and the thinnest end of the slat 111 is the last end of the spring-type acoustic black hole structure 11; the mounting member 12 is disposed at the first end of the spring-type acoustic black hole structure 11.

[0043] In this embodiment, when the slat 111 is fully unfolded, its lower surface 112 (the upper contour surface of the slat 111) is a plane, and its upper surface 113 (the lower contour surface of the slat 111) is a wedge surface. The distance between the plane and the wedge surface is the thickness of the slat 111, which is expressed as y = a1 + εx. m Where y represents the thickness variation of slat 111; ε represents a coefficient; x represents the length variation of slat 111; m is a constant, and m≥2; a1 represents the thickness value of the thinnest end of slat 111. Slat 111 itself is a one-dimensional acoustic black hole. When it is coiled into a spiral in the form of a standard helix, the upper layer 113 rotates with the lower layer 112 while maintaining a relative distance from the lower layer 112 as the outline of a one-dimensional acoustic black hole is maintained.

[0044] In this embodiment, the damping material 13 is preferably a uniformly thick strip-shaped damping structure, which is disposed on the wedge surface of the strip 111, i.e., the upper layer 113, and spirals along with the strip 111. In the acoustic black hole vibration reduction structure 1, the damping material 13 has a spiral strip shape with the same trend as the spring-type acoustic black hole structure 11. As a further preferred embodiment, the width of the strip-shaped damping structure is the same as the width of the strip 111, and the strip-shaped damping structure completely covers the wedge surface of the strip 111, i.e., the upper layer 113.

[0045] In this embodiment, the damping material 13 is preferably a 3M damping sheet.

[0046] In this embodiment, the mounting component 12 is preferably a quarter-circular plate with uniform thickness, and one end of the quarter-circular plate is connected to the first end of the spring-type acoustic black hole structure 11 by an arc transition. The thickness of the quarter-circular plate is preferably the same as the thickness of the first end of the spring-type acoustic black hole structure 11. Generally, the quarter-circular plate is connected to the first end of the spring-type acoustic black hole structure 11 by adhesive bonding or welding. The lower surface 121 of the quarter-circular plate is fixed to the surface of the structure to be damped by adhesive bonding or welding.

[0047] In this embodiment, at least one of the mounting component 12 and the strip 111 is made of photosensitive resin. Preferably, both the mounting component 12 and the strip 111 are made of photosensitive resin and are bonded together.

[0048] The acoustic black hole vibration reduction structure 1 proposed in this technical solution is specifically a spring-type acoustic black hole vibration reduction structure. The first end of the spring-type acoustic black hole structure 11 is fixed to the surface of the structure to be vibration reduced through the lower surface 121 of the quarter-circular ring plate. The vibration energy on the structure to be vibration reduced is transferred to the variable thickness area of ​​the spring-type acoustic black hole structure 11. Combining the characteristics of acoustic black hole vibration reduction and noise reduction, and the dissipation of vibration energy by the uniformly thick spiral strip damping material set on the upper layer of the spring-type acoustic black hole structure 11, the effect of low-frequency vibration reduction is achieved. At the same time, the spiral main structure arrangement of the acoustic black hole vibration reduction structure 1 makes it lightweight and saves installation space.

[0049] The working principle of the acoustic black hole vibration reduction structure 1 described above in this scheme will be explained in detail below with specific examples:

[0050] In the aforementioned acoustic black hole vibration reduction structure 1, the spring-type acoustic black hole structure 11, based on the low fundamental frequency and high modal density of the spring-type acoustic black hole (SABH), exhibits good low-frequency coupling with the main structure. This allows it to generate dynamic vibration absorption in a wider and lower frequency range. Combined with the energy dissipation of the acoustic black hole, it achieves low-frequency and wide-band vibration reduction. The spring-type acoustic black hole structure 11 will be referred to as "SABH" below.

[0051] 1. Formation formula of SABH

[0052] The SABH structure is based on the lower layer 112 of the one-dimensional ABH (i.e., slat 11). The lower layer 112 is spirally coiled in the form of a standard spiral, and the upper layer 113 follows the spiral of the lower layer 112 to ultimately form the SABH. For example... Figure 2As shown, h0 represents the pitch, h1 represents the total height of the SABH, r is the radius of the SABH, and t represents the number of rotations of the helix; x, y, and z represent the length changes in the three spatial directions. The lower layer 112 after rotation is a standard helix, and its parametric equation is:

[0053]

[0054] In the variable-thickness region of a one-dimensional ABH, the thickness variation law of the SABH is the same as that of the one-dimensional ABH structure. To better express the positional relationship between the lower layer 112 and the upper layer 113 in the one-dimensional ABH, we take the lower layer 112 as the x-axis and keep the distance between the upper layer 113 and the lower layer 112 constant. Transforming it to a rectangular coordinate system, we obtain the equation of the upper layer 113 as follows:

[0055] y = a1 + ε*x m

[0056] Where y represents the thickness variation of the one-dimensional ABH; ε represents the coefficient; x represents the length variation of the one-dimensional ABH; m is a constant and m≥2; a1 represents the thickness at the thinnest position of the one-dimensional ABH.

[0057] The purpose of the helical equation is to describe the formation rules of SABH, facilitating the adjustment and design of the SABH structure by changing the parameters in the equation. The parameters of the variable thickness region of SABH are the same as those of the one-dimensional variable thickness region of ABH, that is, the distance in the y-direction between the lower layer 112 and the upper layer 113 remains unchanged before and after rotation, and the one-dimensional variable thickness region of ABH satisfies h(x)=εx m +h0. The entire ABH region has variable thickness.

[0058] 2. Vibration reduction of SABH

[0059] like Figure 7 and Figure 8 As shown, damping material 13 is attached to the upper layer 113 of the SABH to form an acoustic black hole vibration reduction structure 1. The acoustic black hole vibration reduction structure 1 is fixed to the structure to be damped via the lower surface 121 of a quarter-circular plate, which can be an air wing 2.

[0060] The aforementioned quarter-circular plate is formed by an inner ring 122 (i.e., the inner diameter of the SABH helix), an outer ring 123, end plate one 124, and end plate two 125. The inner ring 122 and the outer ring 123 are concentric rings and are on the same plane, while end plate one 124 and end plate two 125 are not on the same plane. The lower surface 121 of the quarter-circular plate is the contact surface for connection with the wing 2.

[0061] The thickness of the SABH decreases exponentially from the thickness of the one-dimensional ABH, coiling the one-dimensional ABH into a spiral shape. The thickness of the SABH is the same as the thickness of the one-dimensional ABH. The exponential expression is y = a1 + ε*x m In the formula, y represents the thickness of the one-dimensional ABH (the thickness of the variable thickness region), ε represents a coefficient, x represents the length of the one-dimensional ABH, m≥2, and a1 represents the minimum thickness of the one-dimensional ABH. The method for determining ε is as follows: first determine the required... Figure 2 The values ​​of the minimum thickness a1 and the maximum thickness a2 of the one-dimensional ABH are then determined according to... Figure 4 Substituting the point into the xoy coordinate system in the expression y = a1 + ε*x m The coefficient ε is obtained through the equation.

[0062] Damping material 13 is adhered to the upper layer 113 of the SABH. Its main function is to dissipate most of the elastic wave energy (vibration energy). The damping material 13 is a strip structure, and it is adhered to an appropriate length on the upper layer 113 from the minimum thickness to the maximum thickness of the SABH. It is not necessary to adhere the damping material 13 to the entire upper layer 113 of the SABH; adhering it from the minimum thickness to the maximum thickness is sufficient. The specific length of the damping material 13 can be determined by the user. Theoretically, the more damping material 13 adhered, the better. However, to reduce mass, often adhering only a small portion can achieve the desired vibration reduction effect.

[0063] The aforementioned SABH is based on the fact that elastic waves in a solid medium decrease with the thickness of the structure according to a certain power law, and the corresponding phase velocity and group velocity also decrease. This allows broadband elastic waves to be concentrated in the thinner region within a certain spatial scale, such as... Figure 8 As shown, the vibration energy on the wing 2 can be transferred to the acoustic black hole vibration damping structure 1 through the quarter-circular plate. In the SABH of the acoustic black hole vibration damping structure 1, the wave propagation speed decreases as the thickness of the SABH decreases, the wavelength decreases, the wave vibration amplitude increases, and the wave concentrates in the region where the thickness of the SABH decreases. By combining the damping material 13, most of the elastic wave energy is consumed, thereby achieving the purpose of high-efficiency energy absorption or vibration reduction and noise reduction.

[0064] The wing 2 of a simple UAV with a total length of 2143.8 mm, a right-end width of 395.5 mm, and a left-end width of 145.8 mm is taken as the controlled object (i.e., the structure to be damped). The acoustic black hole damping structure 1 is attached to the surface of the wing 2 using a quarter-circular ring plate. In the SABH of the acoustic black hole damping structure 1, the pitch h0 is 20 mm; the total height h1 is 150 mm; the inner radius r of the helical structure is 38 mm; the number of rotations t is 7; and the width b of the slat 11 is 40 mm. The minimum thickness a1 of the SABH is 1 mm, the maximum thickness a2 is 7 mm, the power law m is 2, and the coefficient ε is 1.858*10. -6 The wing 2 is made of composite material, while the SABH is made of photosensitive resin. A uniformly thick damping material 13, 238.4 mm long, 40 mm wide, and 1 mm thick, is applied to the SABH. 3M damping material is used, and the material loss factor is set to 0.1. To compare the effects of mass on vibration reduction, a mass block of identical mass and uniform thickness is used as a control group. The width of damping material 13 is the same as the width of the SABH, and its thickness is 1 mm, determined based on the thickness of commonly used damping materials. The thickness of the applied material does not exceed the black hole area, and more damping material 13 is applied without adding excessive extra mass.

[0065] A model of the spring-type acoustic black hole vibration reduction structure was established in ABAQUS (a finite element software for existing engineering simulation) using the finite element method. The damping level and vibration velocity response of the spring-type acoustic black hole vibration reduction structure were calculated through steady-state dynamic analysis and modal superposition method.

[0066] Analysis of calculation results:

[0067] (1) Damping characteristics analysis

[0068] The acoustic black hole vibration damping structure 1 can significantly improve the inherent damping level of the structure, with its system loss factor increasing by 3-40 times across the entire frequency band. After installing a structure of equal mass, the system's damping level remains almost unchanged compared to the original wing structure, demonstrating a significant increase in inherent damping after installing the acoustic black hole vibration damping structure 1. Within the entire frequency band from 1Hz to 50Hz, the acoustic black hole vibration damping structure 1 exhibits excellent damping levels, and the system with the acoustic black hole vibration damping structure 1 possesses 38 modes, 24 more than without it, significantly increasing the system's modal density. In summary, the SABH structure in the acoustic black hole vibration damping structure 1 can significantly improve the damping characteristics of the wing structure, exhibiting richer dynamic characteristics, and is superior to adding a structure of equal mass and damping. This has potential benefits for suppressing low-frequency vibrations in elastic structures, and the lighter mass will not cause damage to the wing or other controlled objects.

[0069] (2) Vibration control characteristic analysis

[0070] To assess the vibration level of the system, the amplitude of the system's origin response displacement is selected as the evaluation index. Figure 10 It can be observed that, after adding the acoustic black hole vibration reduction structure 1 of this technical solution, compared with the original structure, the resonance peaks of all frequencies across the entire frequency band are reduced. Particularly at the first-order vibration at 2.8Hz, the amplitude is attenuated by 79.25%, and amplitude splitting due to dynamic vibration absorption effect is observed. This is because the acoustic black hole vibration reduction structure 1 of this technical solution, due to its helical structure design, generates dynamic vibration absorption and black hole effects at lower frequencies. Combined with high modal density and damping ratio, it is more prone to low-frequency modal coupling, resulting in excellent vibration reduction characteristics for low-frequency vibrations and reducing the low-frequency vibration level of the system. Furthermore, compared with the system with an equal-mass structure, the acoustic black hole vibration reduction structure 1 of this technical solution shows further vibration attenuation at resonance peaks across the entire frequency band. At the first resonance peak, the equal-mass structure only reduces the amplitude by 12.5%, which is 66.75% worse than the attenuation effect of the spring-type acoustic black hole structure. The reason lies in the variable thickness design of the acoustic black hole vibration reduction structure 1, which alters the structure's impedance, causing the propagation speed of elastic waves within the structure to gradually decrease, concentrating vibration energy in the region with the minimum thickness. The helical structure design enables the SABH to achieve frequency matching at the extremely low resonance peak of 2.8Hz, thus exerting a vibration reduction effect. By incorporating a small amount of damping material in the energy concentration region, the structural loss factor is effectively enhanced, energy is absorbed, and low-frequency vibrations of the structure are reduced.

[0071] The acoustic black hole vibration reduction structure 1 in this technical solution cleverly combines the characteristics of acoustic black hole structures, dynamic vibration absorber structures, and spiral structures. It solves the problem of traditional acoustic black holes' ineffective control of low-frequency vibrations. Furthermore, the spiral design, while saving space, increases the modal density of the structure, lowers the lowest frequency that the ABH can control, and improves the coupling efficiency of the ABH's low-frequency modes, exhibiting excellent low-frequency vibration reduction performance. In practical operation, parameters can be designed according to the frequency characteristics of the controlled object to further improve the broadband characteristics.

[0072] The acoustic black hole vibration reduction structure 1 of this technical solution has small added mass, good low-frequency coupling effect, can effectively control extremely low frequency vibration, easily meet engineering applications, and has the characteristics of high efficiency.

[0073] The acoustic black hole vibration reduction structure 1 of this technical solution can widen the frequency band of ABH and reduce the fundamental frequency of ABH by designing ABH as a spring. It can effectively suppress the low-frequency vibration of the structure through ABH, and also solves the problem that ordinary acoustic black holes cannot be effectively designed into structural forms that can control low-frequency vibration.

[0074] The acoustic black hole vibration reduction structure 1 of this technical solution combines the characteristics of a spiral structure and acoustic black hole vibration reduction and noise reduction to achieve lightweight, good low-frequency performance, small footprint, and wide-band vibration reduction. The acoustic black hole vibration reduction and noise reduction is achieved by transferring the vibration energy on the wing to the variable-thickness area of ​​the SABH structure, combined with the damping material adhered thereto dissipating the vibration energy, thereby reducing vibration and solving the problem of low-frequency vibration reduction in structures such as wings. The acoustic black hole vibration reduction structure 1 of this technical solution is lighter than the controlled main structure (the wing structure to be vibration-reduced). Taking this embodiment as an example, installing one SABH to achieve a good vibration reduction effect only adds 6% mass to the wing structure, while traditional vibration reduction often uses damping material, which often adds more than 20% of the mass and cannot effectively control low-frequency vibrations (especially the first-order vibration of the wing). Therefore, the acoustic black hole vibration reduction structure 1 of this technical solution can achieve a lightweight effect while effectively controlling low-frequency vibrations.

[0075] Therefore, compared with the prior art, the advantages of the present invention are as follows:

[0076] 1. The traditional one-dimensional acoustic black hole structure is designed as a spring and combined with a uniform spiral belt structure to effectively control the low-frequency vibration of the structure (the first-order vibration of the wing).

[0077] 2. Designing the one-dimensional acoustic black hole as a spring can broaden the vibration control frequency band of the structure.

[0078] 3. Designing the one-dimensional acoustic black hole part as a spring can enhance the low-frequency coupling between the ABH and the main structure.

[0079] 4. The spring-type acoustic black hole is designed by combining three main structural forms: one-dimensional acoustic black hole, dynamic vibration absorber and spiral structure.

[0080] 5. The SABH structure can be made of high-temperature resistant materials, which can adapt to various complex working conditions of the main structure and avoid damage to the vibration reduction structure under harsh conditions.

[0081] 6. The spring-type acoustic black hole (SABH) can achieve the goals of being lightweight, space-saving, having good low-frequency vibration reduction effect, and wide-frequency vibration reduction.

[0082] It should be noted that, for those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.

[0083] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. An acoustic black hole vibration damping structure, characterized by, The application relates to a spring acoustic black hole structure, which comprises the following components: A spring acoustic black hole structure is formed by spirally winding a strip with one-dimensional acoustic black hole effect, used for absorbing and dissipating vibration energy generated at any position on the structure to be damped; when the strip is fully unfolded, the thickness decreases exponentially from one end to the other end; and the thickest end of the strip is the head end of the spring acoustic black hole structure, and the thinnest end of the strip is the tail end of the spring acoustic black hole structure; the expression of the thickness of the strip is y=a1+εx m ; wherein y represents the thickness change of the strip; ε represents the coefficient; x represents the length change of the strip; m is a constant, and m≥2; a1 represents the thickness value of the thinnest end of the strip. a mounting part arranged at the head end of the spring acoustic black hole structure and used for connecting the spring acoustic black hole structure to a structure to be damped; the mounting part is a quarter circular ring plate with uniform thickness, one end of the quarter circular ring plate is connected to the head end of the spring acoustic black hole structure, and the thickness of the quarter circular ring plate is the same as the thickness of the head end of the spring acoustic black hole structure; a damping material arranged on the surface of the plate strip and used for consuming vibration energy.

2. The acoustic black hole vibration damping structure of claim 1, wherein, When the plate strip is fully unfolded, the lower layer is a plane, the upper layer is a wedge surface, and the distance between the plane and the wedge surface is the thickness of the plate strip.

3. The acoustic black hole vibration damping structure of claim 2, wherein, The damping material is a strip-shaped damping structure with uniform thickness, which is arranged on the wedge surface of the plate strip and is curled with the plate strip.

4. The acoustic black hole vibration damping structure of claim 3, wherein, The width of the strip-shaped damping structure is the same as the width of the plate strip.

5. The acoustic black hole vibration damping structure of claim 1, wherein, The damping material is a 3M damping sheet.

6. The acoustic black hole vibration damping structure of claim 1, wherein, The material of at least one of the mounting part and the plate strip is photosensitive resin.

Images