Thin-layer low-frequency underwater sound insulation metamaterial

Abstract

The invention discloses a thin-layer low-frequency underwater acoustic sound insulation metamaterial. The material comprises two cover plates and a sound insulation layer, and the sound insulation layer is composed of sound insulation assemblies arranged in an array period; each sound insulation assembly comprises sound insulation units and connecting units, each sound insulation unit is of a hollow rectangular column structure, the number of the connecting units is four, the connecting units are arranged at the four corners of each sound insulation unit, and every two adjacent sound insulation units are connected through the corresponding connecting unit; and the included angle between the long side wall of the sound insulation unit and the cover plate is 0-90 degrees. The metamaterial can obtain smaller equivalent acoustic impedance in the sound wave propagation direction, and compared with a square honeycomb structure sound insulation material with the same thickness, the sound insulation performance is greatly improved. The average sound insulation index of the metamaterial in the frequency range of 200Hz-2000Hz is greater than 20dB, and the overall thickness is only 20mm. Under the constraint conditions of light weight and thin layers, the metamaterial shows an excellent sound insulation effect in a low-frequency band, can be applied to sound insulation and noise reduction in underwater equipment or other fields, and has a good engineering application prospect.

Description

technical field [0001] The invention relates to the technical field of vibration and noise control of underwater equipment, in particular to a thin-layer low-frequency underwater sound insulation metamaterial. Background technique [0002] Sticking sound-insulating materials on the surface of underwater equipment is an important technology that can suppress equipment radiation noise and improve its acoustic stealth performance. For sound insulation materials, the sound insulation mechanism mainly has the following two aspects: (1) damping and dissipation sound insulation. The energy of equipment radiating sound waves to the outside is reduced by means of vibration damping dissipation inside the material or scattering sound wave absorption. (2) Impedance mismatch sound insulation. By designing the acoustic structure, the internal noise of the equipment is strongly reflected on the surface of the sound insulation material, thereby reducing the transmitted sound wave energy. ...

AI Technical Summary

Problems solved by technology

(2) Impedance mismatch sound insulation

With the continuous development of the working frequency of detection sonar to the low frequency direction, the effective working frequency of existing sound insulation materials is relatively high, which cannot meet the needs of low frequency applications

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