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Acoustic cover layer beneficial for underwater damping and sound absorbing of ships

A technology of acoustic covering layer and sound-absorbing layer, which is applied in the direction of hull, ship construction, layered products, etc., can solve the problem that it is difficult to achieve satisfactory sound absorption and vibration reduction effects, reduce the target intensity and radiation noise, and have broad application prospects , Good sound attenuation performance

Active Publication Date: 2018-09-18
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, it is usually difficult for homogeneous materials to meet the two conditions of impedance matching and sound attenuation performance of the material at the same time. Traditional cavity resonance and porous energy-absorbing acoustic coatings are difficult to achieve satisfactory sound absorption and vibration reduction effects in practical applications.

Method used

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  • Acoustic cover layer beneficial for underwater damping and sound absorbing of ships
  • Acoustic cover layer beneficial for underwater damping and sound absorbing of ships
  • Acoustic cover layer beneficial for underwater damping and sound absorbing of ships

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] Such as image 3 As shown, the matrix 3-2 and the substrate glass microspheres 3-3 of the sandwich sound-absorbing layer 3 in the acoustic covering layer that is beneficial to underwater vibration and sound absorption of the ship are evenly distributed.

[0030] The following embodiments of the present invention are all based on the underwater acoustic standing wave tube transfer function method to measure the sound absorption coefficient of the acoustic covering layer with different microstructures, and evaluate the sound absorption effect of the sound-absorbing covering layer. The larger the sound absorption coefficient, the better the sound absorption effect . The hydroacoustic standing wave tube transfer function method test system includes a hydroacoustic standing wave tube, an acoustic coating sample, a hydrophone, an acoustic tube, a transmitting transducer, a filter, an oscilloscope, a signal transmitter, a phase meter and a power amplifier; The standing wave t...

Embodiment 2

[0033] Such as Figure 4 As shown, the matrix 3-2 of the sandwich sound-absorbing layer 3 in the acoustic covering layer that is beneficial to underwater vibration and sound absorption of ships is distributed in a functional gradient, while the substrate glass beads 3-3 are uniformly distributed. The density and acoustic impedance of the sandwich sound-absorbing layer 3 at the interface with the surface layer 1 match the water / surface layer, and are close to the density and impedance of the ship's shell 2 along the gradient.

[0034]The matrix of the sandwich sound-absorbing layer 3 of this embodiment is prepared by a temperature gradient curing method, a layering method or a mechanical continuous method of controlling component flow. The above production methods can be seen from Zhou Chengfei. The research status and prospect of polyurethane functionally graded materials[J]. Chemical Technology and Development, 2013(5):9-13.

[0035] Among them, 1) temperature gradient curin...

Embodiment 3

[0040] Such as Figure 5 As shown, the matrix polyurethane 3-2 and the substrate glass microbeads 3-3 of the sandwich sound-absorbing layer 3 in the viscoelastic inclusion functionally graded acoustic covering layer are all distributed in a functional gradient. Embodiment 3 adopts a layered preparation method: through continuous Change the ratio of polyurethane and vermiculite powder, lay them layer by layer in order, and finally get the gradient material. In this method, the glass microspheres 3-3 need to be added layer by layer together with the polyurethane prepolymer and vermiculite powder, and the addition amount of the glass microspheres 3-3 in each layer is distributed in a gradient, so that the matrix 3-2 is distributed in a functional gradient , while the base glass microspheres 3-3 are distributed in a gradient. The hollow glass microspheres in Example 3 are distributed in a functional gradient. From the surface layer to the hull of the ship along the thickness dire...

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Abstract

The invention discloses an acoustic cover layer beneficial for underwater damping and sound absorbing of ships. The cover layer is composed of a surface layer, a sandwich sound absorbing layer, and anadhesive layer. The surface layer is made of glass fiber reinforced plastic, wherein the density of the glass fiber reinforced plastic is close to water density, and the impedances of the glass fiberreinforced plastic and water are matched. The sandwich sound absorbing layer is composed of polyurethane and vermiculite powder and is prepared by a layering method. The sandwich sound absorbing layer has a functional gradient structure, whose material parameters change along with the thickness direction. Hollow glass beads are distributed in the sandwich sound absorbing layer; the content of thehollow glass beads decreases from outer to inner along with the thickness direction, the density increases; the adhesive layer and the surface layer are adhered on the steel shell of a ship, and theadhesive layer is made of an visco-elastic material. The cover layer satisfies two conditions that the impedances are matched and the sound attenuation performance is good; the target strength and radiation noise of ships and underwater structures can be reduced effectively; the anti-detection performance and stealth performance of ships and underwater structures are both improved; and the cover layer has a wide application prospect in fields such as military ships, civilian ships, underwater structures, and the like.

Description

technical field [0001] The invention relates to the technical field of vibration reduction and sound absorption, in particular to an acoustic covering layer beneficial to underwater vibration reduction and sound absorption of ships. Background technique [0002] Underwater sound absorption and vibration reduction is an important topic in the disciplines of underwater acoustic engineering, ship engineering and marine engineering. Unlike in the air, radar electromagnetic waves attenuate quickly underwater and are difficult to use, while sound waves can travel very far in incompressible water (sonar detection range can reach 10 to 35 nautical miles). Therefore, passive sonar, active sonar, and sound-absorbing coatings on the surface of ships are the main means of underwater acoustic countermeasures. At the same time, noise is also one of the main sources of underwater pollution. Therefore, it is necessary to lay sound-absorbing and vibration-damping coverings on the surface of...

Claims

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Application Information

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IPC IPC(8): B32B27/06B32B33/00B32B27/40B32B7/10B32B15/18B32B15/04B63B3/14
CPCB32B7/10B32B15/04B32B15/18B32B27/06B32B27/40B32B33/00B32B2262/101B32B2264/101B32B2264/104B32B2307/102B32B2307/552B32B2307/714B32B2605/12B63B3/14
Inventor 梁旭王体涛王立忠邓禹阮永都王玉红
Owner ZHEJIANG UNIV
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