Acoustic black hole composite vibration reduction structure with built-in particle damping

Abstract

The invention relates to the field of vibration reduction devices, and particularly discloses an acoustic black hole composite vibration reduction structure with built-in particle dampers, which comprises the particle dampers, connecting pieces and acoustic black hole plates, each particle damper comprises a shell with two open ends, a base and a top cover, the base and the top cover are fixedly connected to the two open ends of the shell, the shell is filled with damping particles, and the connecting pieces are connected with the damping particles. The base is connected to a vibration source; the connecting piece comprises a connecting rod and a connecting plate which are fixedly connected, the connecting rod penetrates through the top cover, and the connecting plate is located in the shell and embedded in the damping particles; the acoustic black hole plate is fixedly connected to the end, located outside the shell, of the connecting rod. According to the composite vibration reduction structure, vibration energy is transmitted to the acoustic black hole plate through particle damping with the nonlinear damping characteristic, the action frequency band of the composite vibration reduction structure is enriched, and the vibration reduction performance of a low-frequency line spectrum is improved.

Description

Technical Field

[0001] The present application relates to the field of vibration reduction devices, and in particular to an acoustic black hole composite vibration reduction structure with built-in particle damping. Background Art

[0002] Mechanical noise, propeller noise and hydrodynamic noise are the three major noise sources of ships. Among them, the mechanical noise of ships comes from the simultaneous operation of multiple large equipment including power units and auxiliary machines. These equipment will generate low-frequency line spectrum components in the frequency range of several hertz to several hundred hertz during operation. The low-frequency line spectrum contributes greatly to the total noise level of underwater vehicles. Low-frequency vibrations and the low-frequency sound waves caused by them have less attenuation in seawater and propagate over a long distance. Conventional solutions can only reduce the vibration magnitude in the medium and high frequency bands, but it is difficult to eliminate the low-frequency vibration line spectrum caused by the low-speed operation of large equipment. Therefore, underwater vehicles urgently need to use new technical means to break through the problem of efficient control of low-frequency line spectrum vibration.

[0003] As a new wave manipulation technology, acoustic black hole (ABH) has great advantages in vibration and noise reduction in recent years due to its light weight, easy installation, and good vibration reduction effect, and has attracted extensive attention from many scholars. However, various acoustic black hole vibration reduction structures are currently mainly used for vibration reduction problems in mid- and high-frequency bands, and vibration suppression of low-frequency line spectra is still a problem. Summary of the invention

[0004] In order to improve the problem of poor vibration reduction effect of low-frequency line spectrum of traditional acoustic black holes, the present application provides an acoustic black hole composite vibration reduction structure with built-in particle damping.

[0005] The present application provides an acoustic black hole composite vibration reduction structure with built-in particle damping, which adopts the following technical solution: An acoustic black hole composite vibration reduction structure with built-in particle damping, comprising: The particle damper comprises a shell with openings at both ends and a base and a top cover fixed to the two opening ends of the shell, the shell is filled with damping particles, and the base is connected to a vibration source; A connecting member, comprising a connecting rod and a connecting plate that are fixedly connected, wherein the connecting rod passes through the top cover, and the connecting plate is located in the shell and buried in the damping particles; The acoustic black hole plate is fixedly connected to one end of the connecting rod located outside the shell.

[0006] When in use, the base of the particle damper is fixed on the vibration source. While the vibration energy is consumed by mutual collision and friction between the damping particles, the nonlinear damping characteristics of the particle damping are brought into play. The connecting piece transmits the vibration to the acoustic black hole plate. Due to the change in the thickness of the acoustic black hole itself, the vibration energy is gathered at the truncation of the acoustic black hole structure and dissipated through the additional damping layer. This application enriches the action frequency band of the composite vibration reduction structure by cooperating with the particle damper and the acoustic black hole, and improves the vibration reduction performance of the low-frequency line spectrum.

[0007] Furthermore, the connecting plate divides the shell into two chambers, namely a first chamber close to the top cover and a second chamber close to the base. The particle sizes of the damping particles in the first chamber and the second chamber are different.

[0008] Furthermore, the particle size of the damping particles in the first chamber is smaller than the particle size of the damping particles in the second chamber.

[0009] Furthermore, the second chamber is filled with damping particles.

[0010] Further, the first chamber is not filled with damping particles, so that there is a gap between the surface layer of the damping particles in the first chamber and the top cover.

[0011] The large-size damping particles in the second chamber mainly play the role of support and friction energy consumption. There is a certain gap between the surface of the small-size damping particles in the first chamber and the top cover, which makes it more likely to have a two-way Leidenfrost effect, greatly increasing energy consumption.

[0012] Furthermore, the outer circumference of the connecting plate is smaller than the inner circumference of the shell.

[0013] Furthermore, the top cover is provided with a through hole for the connecting rod to pass through, and the diameter of the through hole is larger than the outer diameter of the connecting rod.

[0014] During use, there is a collision between the peripheral side of the connecting plate and the inner wall of the shell, and there is also a collision between the connecting rod and the inner wall of the through hole, so that the device as a whole has nonlinear characteristics, which can better transmit and dissipate the vibration energy of the vibration source.

[0015] Furthermore, the connecting plate is made of flexible material.

[0016] The flexible connecting plate is conducive to intensifying the vibration of the small-diameter damping particles in the first chamber, thereby further increasing the energy consumption.

[0017] Furthermore, the acoustic black hole plate is a rectangular eccentric acoustic black hole plate.

[0018] Furthermore, damping layers are respectively provided at the two end truncation areas of the rectangular eccentric acoustic black hole plate.

[0019] Compared with ordinary acoustic black holes, eccentric acoustic black holes have higher effective modal density and modal damping ratio, better broadband characteristics, and can achieve good vibration reduction effects without special optimization design.

[0020] In summary, the present application includes at least one of the following beneficial technical effects: 1. The present application utilizes an eccentric acoustic black hole plate structure, and based on its high modal density and multiple modal vibration characteristics, combines particle damping technology to transfer vibration energy to the acoustic black hole plate through particle damping with nonlinear damping characteristics, which can enrich the action frequency band of the vibration reduction structure, so that the acoustic black hole vibration reduction structure with a built-in particle damping connection device has a wider band gap characteristic and improves the defect of poor low-frequency line spectrum vibration reduction effect of the traditional acoustic black hole, and has a significant vibration reduction effect in the case of low-frequency line spectrum vibration; 2. By arranging damping particles of different sizes on both sides of the connecting plate and reserving a gap between the surface of the small-size damping particles and the top cover, the large-size damping particles are used to play a supporting and frictional energy dissipation role, and the bidirectional Leidenfrost effect of the small-size damping particles is used to greatly increase energy dissipation; 3. By providing a flexible connecting plate, it is helpful to intensify the vibration of the small-size damping particles in the first chamber, thereby further increasing energy consumption; 4. By setting the size difference between the connecting plate and the shell, and setting the size difference between the connecting rod and the top cover through hole, the device as a whole has nonlinear characteristics, which can better transmit and dissipate the vibration energy of the vibration source. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic diagram of the overall cross-sectional structure of an embodiment of the present application; Figure 2 It is a schematic diagram of the explosion structure of an embodiment of the present application; Figure 3 It is a schematic diagram comparing the simulation effects of the embodiments of the present application.

[0022] Figure numerals: 1. acoustic black hole plate; 11. damping layer; 2. particle damper; 21. base; 22. shell; 221. first chamber; 222. second chamber; 23. top cover; 24. damping particles; 3. connecting member; 31. connecting rod; 32. connecting plate. DETAILED DESCRIPTION

[0023] The following is combined with Figure 1-3 This application is described in further detail.

[0024] The present application embodiment discloses an acoustic black hole composite vibration reduction structure with built-in particle damping. Figure 1 and Figure 2The acoustic black hole composite vibration reduction structure with built-in particle damping includes a particle damper 2, a connector 3 and an acoustic black hole plate 1.

[0025] Reference Figure 1 and Figure 2 The particle damper 2 includes a shell 22 with openings at both ends, a base 21 and a top cover 23 fixed to the two open ends of the shell 22. The shell 22 is cylindrical, with a diameter of 50-200mm, a height of 10-80mm, and a thickness of 5-15mm; the top cover 23 is adapted to the shape of the shell 22, and the top cover 23 and the shell 22 can be connected by screw connection or integral molding. The base 21 is square, with a side length of 80-250mm and a thickness of 2-5mm. The shell 22 is connected to the base 21 by six screws, and the base 21 is connected to the vibration source by four screws.

[0026] Reference Figure 1 The shell 22 is filled with damping particles 24, which are spherical and made of iron-based particles, tungsten-based particles, copper particles, aluminum particles, lead particles or acrylic particles, and have a recovery coefficient e of 0.1-0.9.

[0027] Reference Figure 1 and Figure 2 The connecting member 3 includes a connecting rod 31 and a connecting plate 32 which are fixedly connected. The connecting rod 31 is a hollow round rod. A through hole is provided in the center of the top cover 23 for the connecting rod 31 to pass through. The aperture of the through hole is 1-2 mm larger than the outer diameter of the connecting rod 31. The connecting plate 32 is a circular plate made of a flexible material, which may be made of rubber, silicone and other materials, and has a thickness of 2-5 mm. The diameter of the connecting plate 32 is 1 mm smaller than the inner diameter of the housing 22. The connecting plate 32 is located in the housing 22 and is buried in the damping particles 24.

[0028] Reference Figure 1 The connecting plate 32 divides the shell 22 into two chambers, namely a first chamber 221 close to the top cover 23 and a second chamber 222 close to the base 21. The particle size of the damping particles 24 in the first chamber 221 is 1-4 mm, and the particle size of the damping particles 24 in the second chamber 222 is 4 mm larger than that of the damping particles 24 in the first chamber 221.

[0029] Reference Figure 1 , the second chamber 222 is filled with damping particles 24; the first chamber 221 is not filled with damping particles 24, so that there is a gap between the surface of the damping particles 24 in the first chamber 221 and the top cover 23. Specifically, the filling thickness of the damping particles 24 in the first chamber 221 is h1, the gap between the surface of the damping particles 24 and the top cover 23 is h2, and h1 / (h1+h2)=0.7.

[0030] Reference Figure 1 and Figure 2 The acoustic black hole plate 1 is a rectangular eccentric acoustic black hole plate 1, and the center of its uniform layer is connected to the end of the connecting rod 31 by screws. The radius of the black hole surface on one side of the rectangular eccentric acoustic black hole plate 1 is 100-300mm, the height is 5-20mm, the power exponent of the acoustic black hole parameter equation is m = 2-4, and the thickness of the uniform layer is 5-15mm; the radius of the black hole surface on the other side is 100-300mm, the height is 5-20mm, the power exponent of the acoustic black hole parameter equation is m = 2~4, and the thickness of the uniform layer is 5-15mm. The truncated areas at both ends of the rectangular eccentric acoustic black hole plate 1 are respectively pasted with a 2mm thick nitrile rubber damping layer 11.

[0031] The acoustic black hole plate 1, the connecting rod 31, the shell 22, the top cover 23 and the base 21 can all be processed by materials such as resin, carbon fiber, nylon, ABS, steel, titanium or aluminum.

[0032] The acoustic black hole composite vibration reduction structure with built-in particle damping in the present application is placed on a flat plate to simulate the vibration reduction characteristics, with a sweep frequency range of 1-5000Hz. Figure 3 As shown, the results show that the acoustic black hole composite vibration reduction structure with built-in particle damping of the present application has better vibration reduction effect than the ordinary acoustic black hole structure. Compared with the vibration response of the flat plate near 41Hz, the acoustic black hole composite vibration reduction structure with built-in particle damping of the present application has a 9.91dB reduction in the vibration acceleration level, and the total vibration acceleration level in the frequency band of 1-5000Hz is attenuated by 27.7dB compared with the flat plate.

[0033] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. An acoustic black hole composite vibration reduction structure with built-in particle damping, characterized in that: include: The particle damper comprises a shell with openings at both ends and a base and a top cover fixed to the two opening ends of the shell, the shell is filled with damping particles, and the base is connected to a vibration source; A connecting member, comprising a connecting rod and a connecting plate that are fixedly connected, wherein the connecting rod passes through the top cover, and the connecting plate is located in the shell and buried in the damping particles; The acoustic black hole plate is fixedly connected to one end of the connecting rod located outside the shell.

2. The acoustic black hole composite vibration reduction structure with built-in particle damping according to claim 1, characterized in that: The connecting plate divides the shell into two chambers, namely a first chamber close to the top cover and a second chamber close to the base. The particle sizes of the damping particles in the first chamber and the second chamber are different.

3. The acoustic black hole composite vibration reduction structure with built-in particle damping according to claim 2, characterized in that: The particle size of the damping particles in the first chamber is smaller than the particle size of the damping particles in the second chamber.

4. The acoustic black hole composite vibration reduction structure with built-in particle damping according to claim 3, characterized in that: The second chamber is filled with damping particles.

5. The acoustic black hole composite vibration reduction structure with built-in particle damping according to claim 3, characterized in that: The first chamber is not filled with damping particles, so that there is a gap between the surface layer of the damping particles in the first chamber and the top cover.

6. The acoustic black hole composite vibration reduction structure with built-in particle damping according to claim 1, characterized in that: The outer circumference size of the connecting plate is smaller than the inner circumference size of the shell.

7. The acoustic black hole composite vibration reduction structure with built-in particle damping according to claim 6, characterized in that: The connecting plate is made of flexible material.

8. The acoustic black hole composite vibration reduction structure with built-in particle damping according to claim 1, characterized in that: The top cover is provided with a through hole for the connecting rod to pass through, and the diameter of the through hole is larger than the outer diameter of the connecting rod.

9. The acoustic black hole composite vibration reduction structure with built-in particle damping according to claim 1, characterized in that: The acoustic black hole plate is a rectangular eccentric acoustic black hole plate.

10. The acoustic black hole composite vibration reduction structure with built-in particle damping according to claim 9, characterized in that: Damping layers are respectively arranged at the two end truncation areas of the rectangular eccentric acoustic black hole plate.

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