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A double helix, coupled water technology, applied in the direction of sound-producing equipment, instruments, etc., can solve the problems of poor low-frequency sound absorption performance and large structural thickness, and achieve excellent deep sub-wavelength structure size, reduce thickness, and improve acoustic impedance characteristics. Effect
Pending Publication Date: 2021-01-05
XI AN JIAOTONG UNIV
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[0005] The technical problem to be solved by the present invention is to provide a double-helix coupling underwater sound-absorbing metasurface structure to solve the problems of poor low-frequency sound-absorbing performance and structural thickness in traditional underwater sound-absorbing structures. big problem
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Embodiment 1
[0054] The diameter of the small hole is 4.8mm, the thickness of the perforated upper panel is 0.5mm, the width of the spiral channel is 8.8mm, the height is 19.4mm, the thickness of the damping inner lining is 2.4mm, the thickness of the annular partition is 0.2mm, and the length of the cavity is 5.8mm , the number of spiral turns is 3 turns.
Embodiment 2
[0056] The diameter of the small hole is 3.3mm, the thickness of the perforated upper panel is 0.2mm, the width of the spiral channel is 6.4mm, the height is 17.8mm, the thickness of the damping inner lining is 1.7mm, the thickness of the annular partition is 0.2mm, and the length of the cavity is 4.3mm , the number of spiral turns is 3 turns.
Embodiment 3
[0058] The diameter of the small hole is 2.6mm, the thickness of the perforated upper panel is 1.5mm, the width of the spiral channel is 7.6mm, the height is 18.1mm, the thickness of the damping inner lining is 1.9mm, the thickness of the annular partition is 0.2mm, and the length of the cavity is 3.6mm , the number of spiral turns is 3 turns.
[0059] see image 3 , Example 1 achieves perfect sound absorption at 151Hz, the maximum value of the sound absorption coefficient is 0.99, and the thickness of the structure is 1 / 497 of the wavelength;
[0060] Example 2 achieves perfect sound absorption at 215Hz, the maximum value of the sound absorption coefficient is 0.99, and the thickness of the structure is 1 / 387 of the wavelength;
[0061] Example 3 achieves perfect sound absorption at 182Hz, the maximum value of the sound absorption coefficient is 0.99, and the thickness of the structure is 1 / 421 of the wavelength;
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Abstract
The invention discloses a double-helix coupling underwater sound absorption metasurface structure which comprises a layer core, a plurality of double-helix coupling units are arranged in the layer core at intervals, a cavity is formed in the spiral center of each double-helix coupling unit, an annular partition plate is arranged between each cavity and a spiral channel, and a spiral damping lininglayer is arranged on the side wall of each spiral channel. A perforated upper panel is arranged at the top of the layer core, small holes are periodically formed in the perforated upper panel corresponding to cavities of the double-helix coupling units, a lower panel is arranged at the bottom of the layer core, and the perforated upper panel, the layer core and the lower panel are connected to form a double-helix coupling underwater sound absorption metasurface structure. The double-helix coupling underwater sound absorption metasurface structure has excellent low-frequency sound-absorbing performance and ultra-thin sub-wavelength structure size. And more adjustable structural parameters are provided in the design aspect, corresponding adjustment can be conducted according to actual working condition requirements, the structure is simple, and manufacturing is easy.
Description
technical field [0001] The invention belongs to the technical field of acoustic metasurfaces, and in particular relates to a double-helix coupling underwater sound-absorbing metasurface structure. Background technique [0002] With the continuous development of marine equipment, the effective absorption of underwater sound waves has attracted more and more attention. Traditional underwater sound-absorbing materials or structures, including pure polymer underwater sound-absorbing materials, particle-filled underwater sound-absorbing materials, cavity-resonant underwater sound-absorbing materials and porous underwater sound-absorbing materials, etc. Large, the structure size is close to the wavelength of the sound wave, and the low-frequency sound absorption performance is poor. The underwater sound-absorbing metamaterials that have emerged in recent years include local resonant underwater sound-absorbing metamaterials and non-resonant underwater sound-absorbing metamaterials...
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