Bionic high-bearing Helmholtz resonator

Abstract

The invention discloses a bionic high-bearing-capacity Helmholtz resonator, belongs to the field of engineering bionics and acoustic superstructures, and aims to solve the technical problem that a traditional sound absorption material and excellent mechanical properties are difficult to integrate. The resonator comprises a plurality of top plates, a plurality of bionic Helmholtz resonator arrays and a bottom plate, one top plate is positioned above one bionic Helmholtz resonator array to form a group of bionic Helmholtz resonator array units, the plurality of bionic Helmholtz resonator array units are arranged from top to bottom, and the lowest bionic Helmholtz resonator array unit is arranged on the bottom plate. On the premise of perfecting the structural design of the sound absorption cavity and having a high sound absorption coefficient, the structure of the sound absorption unit is remodeled, the overall toughness and strength of the sound absorption device are remarkably improved, the service life of the sound absorption device is prolonged, and a novel application direction is developed. The overall sound absorption structure is light, thin and compact, the mechanical properties such as compression resistance and bending resistance are remarkably improved, and manufacturing and using are easy.

Description

Technical Field

[0001] The invention belongs to the field of engineering bionics and acoustic superstructures, and relates to a bionic high-load Helmholtz resonator. Background Art

[0002] As the impact of noise on human production and life increases, how to effectively absorb low-frequency noise has become a research focus. As an effective sound-absorbing structure, the acoustic Helmholtz unit has received widespread attention. The Helmholtz unit consists of a closed resonant cavity and a connected neck tube. When sound waves propagate to the resonant cavity, if the frequency of the incident sound wave is the same as the natural vibration frequency of the resonant cavity, resonance will occur. This resonance process converts the energy of the sound wave into heat energy, thereby achieving noise absorption.

[0003] Helmholtz units are widely used in passenger equipment such as aerospace and rail transportation, as well as certain military equipment that requires covert operation. In addition to sound absorption performance, the mechanical properties of Helmholtz units are also crucial. As a common engineering structure, Helmholtz units are usually wrapped around noise sources such as engines. They not only need to absorb sound, but also must have excellent vibration reduction and energy absorption capabilities. This mechanical property can not only reduce noise transmission, but also provide protection for key components in accidents and reduce impact damage.

[0004] Therefore, further optimizing the mechanical properties of the Helmholtz unit will provide comprehensive technical support for solving broadband noise problems and lay the foundation for the design of multifunctional acoustic structures. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the present invention provides a bionic high-load Helmholtz resonator, which aims to solve the technical problem that it is difficult to combine traditional sound-absorbing materials with excellent mechanical properties.

[0006] The technical solution adopted by the present invention to solve the technical problem is as follows: A bionic high-load Helmholtz resonator comprises a plurality of top plates, a plurality of bionic Helmholtz resonator arrays and a bottom plate; one of the top plates is located above a bionic Helmholtz resonator array to form a group of bionic Helmholtz resonator array units, a plurality of the bionic Helmholtz resonator array units are arranged from top to bottom, and the lowest bionic Helmholtz resonator array unit is arranged on the bottom plate.

[0007] Preferably, the bionic Helmholtz resonator array is composed of a plurality of bionic Helmholtz resonator monomers.

[0008] Preferably, the bionic Helmholtz resonator monomer consists of a bionic Helmholtz resonator unit shell and a bionic Helmholtz resonator unit cavity.

[0009] Preferably, the bionic Helmholtz resonator unit cavity is a variable cross-section hollow structure with a predetermined wall thickness to length ratio.

[0010] Preferably, the upper bottom surface of the bionic Helmholtz resonator unit cavity is circular, the lower bottom surface is square, and the center line of the upper and lower bottom surfaces is perpendicular to the upper and lower bottom surfaces respectively.

[0011] Preferably, the variable cross-section of the housing of the bionic Helmholtz resonator unit has a taper.

[0012] Preferably, a plurality of sound absorption cavity communication holes are provided on the top plate.

[0013] Preferably, the connecting hole of the sound absorption cavity is a cylinder, the diameter of the cylinder is smaller than the diameter of the upper bottom surface of the bionic Helmholtz resonator unit cavity, and the central axis of the cylinder coincides with the line connecting the upper and lower bottom surfaces.

[0014] The beneficial effects of the present invention are as follows: the present invention reshapes the sound absorption unit structure by using the bionic energy absorption structure and the bamboo joint variable taper structure and the bird feather shaft variable cross-section structure in nature, while satisfying the requirements of perfecting the sound absorption cavity structure design and having a high sound absorption coefficient, significantly improving the overall toughness and strength of the sound absorption device, while extending the service life of the sound absorption device and developing new application directions. The overall structure of the sound absorption structure proposed by the present invention is thin and compact, and the mechanical properties such as compression resistance and bending resistance are significantly improved, and it is easy to manufacture and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic diagram of the three-dimensional structure of a bionic high-load-bearing Helmholtz resonator of the present invention.

[0016] Figure 2 A cross-sectional view of a resonance unit of a bionic high-load-bearing Helmholtz resonator according to the present invention taken along the BB direction.

[0017] Figure 3 It is a curve diagram of the sound absorption effect of different sound hole diameters in different bands in an embodiment of a bionic high-load Helmholtz resonator of the present invention.

[0018] In the figure: 10, top plate, 11, sound absorption cavity connecting hole, 20, bionic Helmholtz resonator array, 21, bionic Helmholtz resonator monomer, 22, bionic Helmholtz resonator unit shell, 23, bionic Helmholtz resonator unit cavity, 30, bottom plate. DETAILED DESCRIPTION

[0019] In order to make the above features and advantages of the present invention more obvious and understandable, the present invention is further described in detail below with reference to the accompanying drawings, but this should not limit the protection scope of the present invention.

[0020] like Figure 1As shown, a bionic high-load Helmholtz resonator includes multiple top plates 10, multiple bionic Helmholtz resonator arrays 20 and a bottom plate 30; a top plate 10 is located above a bionic Helmholtz resonator array 20 to form a group of bionic Helmholtz resonator array units, multiple bionic Helmholtz resonator array units are arranged from top to bottom, and the bottom bionic Helmholtz resonator array unit is arranged on the bottom plate 30. The bionic Helmholtz resonator array is composed of multiple bionic Helmholtz resonator monomers 21, which are closely arranged according to their own geometric characteristics to form a bionic Helmholtz resonator array 20. The bionic Helmholtz resonator monomers 21 include but are not limited to other arrangement styles such as circular arrays and prism arrays. The bionic Helmholtz resonator array 20 of this embodiment only needs to be connected to the contact surface between the upper and lower top plates 10, and there is no need to connect different bionic Helmholtz resonator monomers 21. This simplifies the manufacturing process while ensuring the sound absorption and energy absorption efficiency, and reduces the use of auxiliary materials such as adhesives and structural design defects caused by interface connection. The present invention is closely arranged according to the geometric characteristics of the bionic Helmholtz resonator monomers 21, so that the structural characteristics of the bionic Helmholtz resonator monomers 21 are fully utilized. At the same time, the enclosed space is conducive to converting the impact kinetic energy into heat energy dissipation, so that its energy absorption characteristics are further enhanced. In this embodiment, a plurality of bionic Helmholtz resonator monomers 21 are arranged in a rectangular array with a center distance of 5mm*5mm.

[0021] like Figure 2 As shown, the bionic Helmholtz resonator monomer 21 is composed of a bionic Helmholtz resonator unit shell 22 and a bionic Helmholtz resonator unit cavity 23. The bionic Helmholtz resonator unit cavity 23 of this embodiment structurally simulates the structural characteristics of the taper inside the bamboo node and the variable cross-section of the feather shaft of birds. The bionic Helmholtz resonator unit cavity 23 is a variable cross-section hollow structure with a predetermined wall thickness to length ratio. The variable cross-section of the bionic Helmholtz resonator unit shell 22 has a taper. In this embodiment, the taper of the inner wall of the bionic Helmholtz resonator unit shell 22 is within 0.002-0.003, and the ratio of the maximum wall thickness to the outer diameter of the bionic Helmholtz resonator unit shell 22 is not higher than 0.5. The upper bottom surface of the bionic Helmholtz resonator unit cavity 23 is circular, the lower bottom surface is square, and the center line of the upper and lower bottom surfaces is perpendicular to the upper and lower bottom surfaces respectively. In this embodiment, the circular diameter D 2 =2.8mm, square side length L 3 =3mm, bionic Helmholtz resonator unit cavity 23 high H 2 =8mm, the maximum wall thickness L of the bionic Helmholtz resonator unit housing 22 1 =1.024mm, minimum wall thickness L 2 =1mm.

[0022] The bionic Helmholtz resonator unit cavity 23 mainly plays two roles. First, it provides a sound-absorbing structural cavity. Based on the resonance of the bionic Helmholtz resonator monomer 21, the sound wave energy is dissipated to achieve a predetermined sound absorption effect. Second, the bionic Helmholtz resonator unit shell 22 is used as the main mechanical bearing structure to enhance the stability and large deformation resistance of the overall bionic Helmholtz resonator monomer 21.

[0023] The bionic Helmholtz resonator monomer 21 adopts a hollow cavity structure with a variable shape cross section and gradient wall thickness, which changes its deformation mode when bearing impact and other loads. The gradual stability of the gradient wall thickness structure can extend the deformation stroke and ensure the stable energy absorption of the structure. At the same time, the regular upper and lower cross sections can simplify manufacturing and meet the requirements of specific array arrangement.

[0024] The top plate 10 is provided with a plurality of sound absorbing cavity communication holes 11. The top plate 10 has a thickness H 1 =1mm, the diameter D of the sound absorption cavity communication hole 11 1 =1.36mm. The sound absorption cavity connecting hole 11 is a cylinder, the diameter of which is smaller than the diameter of the upper bottom surface of the bionic Helmholtz resonator unit cavity 23, and the central axis of the cylinder coincides with the line connecting the upper and lower bottom surfaces. The thickness H of the bottom plate 30 is 3 =2mm.

[0025] like Figure 3 As shown, the materials used in the simulation are as follows: the density of the photosensitive resin is 1150kg / m 3 , Young's modulus 3.5GPa, Poisson's ratio 0.35; the density of air is 1.29kg / m 3 , speed of sound 343m / s, dynamic viscosity coefficient 1.81×10 -5 Pa•s.

[0026] The above materials were used to test and simulate the sound absorption cavity communication holes 11 of different sizes. After structural design, the sound absorption device can achieve excellent sound absorption effects in different bands. In particular, for the sound absorption structure bionic Helmholtz resonator array 20 with a sound absorption cavity communication hole 11 of 1.36 mm, the sound absorption coefficient of the bionic Helmholtz resonator array 20 in the 3200Hz to 3600Hz band is above 0.4, achieving a medium sound absorption effect; the sound absorption coefficient in the 3315Hz to 3470Hz band is above 0.8, achieving a high sound absorption effect; and the highest sound absorption coefficient of 0.9993 is achieved in the 3391Hz band, which can be considered to achieve complete sound absorption in this band.

[0027] The above results show that by designing the cavity structure and changing the aperture of the sound absorption cavity connecting hole 11, the bionic Helmholtz resonator array 20 can have better sound absorption performance at different frequencies. Combining multiple bionic Helmholtz resonator unit cavities 23 with specific parameters can achieve both sound absorption performance and lightweight energy absorption performance within a wide frequency range.

[0028] In this embodiment, compared with the traditional Helmholtz resonance structure, the structural bearing capacity and energy absorption effect are enhanced, which is suitable for the design and preparation of sound absorption and energy absorption coupling materials for large equipment.

Claims

1. A bionic high-load Helmholtz resonator, characterized in that: The resonator comprises a plurality of top plates, a plurality of bionic Helmholtz resonator arrays and a bottom plate; one of the top plates is located above one of the bionic Helmholtz resonator arrays to form a group of bionic Helmholtz resonator array units, the plurality of bionic Helmholtz resonator array units are arranged from top to bottom, and the lowest bionic Helmholtz resonator array unit is arranged on the bottom plate.

2. A bionic high-load Helmholtz resonator according to claim 1, characterized in that: The bionic Helmholtz resonator array is composed of a plurality of bionic Helmholtz resonator monomers.

3. A bionic high-load Helmholtz resonator according to claim 2, characterized in that: The bionic Helmholtz resonator monomer consists of a bionic Helmholtz resonator unit shell and a bionic Helmholtz resonator unit cavity.

4. A bionic high-load Helmholtz resonator according to claim 3, characterized in that: The bionic Helmholtz resonator unit cavity is a variable cross-section hollow structure with a predetermined wall thickness to length ratio.

5. The bionic high-load Helmholtz resonator according to claim 3, characterized in that: The upper bottom surface of the bionic Helmholtz resonator unit cavity is circular, the lower bottom surface is square, and the center line of the upper and lower bottom surfaces is perpendicular to the upper and lower bottom surfaces respectively.

6. The bionic high-load Helmholtz resonator according to claim 3, characterized in that: The variable cross-section of the housing of the bionic Helmholtz resonator unit has a taper.

7. The bionic high-load Helmholtz resonator according to claim 5, characterized in that: The top plate is provided with a plurality of sound absorbing cavity communication holes.

8. The bionic high-load Helmholtz resonator according to claim 7, characterized in that: The sound absorption cavity communication hole is a cylinder, the diameter of the cylinder is smaller than the diameter of the upper bottom surface of the bionic Helmholtz resonator unit cavity, and the central axis of the cylinder coincides with the line connecting the upper and lower bottom surfaces.

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