CN106847253A - Acoustic cladding with honeycomb cavity structure - Google Patents

Abstract

The invention discloses an acoustic covering layer with a honeycomb cavity structure, which comprises a damping layer, the damping layer contains periodically horizontally arranged honeycomb cavities, the damping layer includes a rubber layer or a polymer resin layer, and the center line of the honeycomb cavity is in line with the The direction of propagation of elastic or sound waves is perpendicular. The invention can effectively improve the performance of vibration suppression and sound insulation, and also has a certain sound absorption performance and impact resistance, can effectively reduce the target intensity and radiation noise of the underwater structure, and plays an important role in improving the stealth ability of the underwater structure.

Description

Acoustic cladding with honeycomb cavity structure

technical field

The invention belongs to the technical field of vibration reduction and noise reduction, and in particular relates to an acoustic covering layer of a honeycomb cavity structure.

Background technique

Sound waves are the only form of energy that can travel long distances in the ocean. At present and in the foreseeable future, underwater detection will still rely on the detection of changes in the sound field. Therefore, reducing its own radiation noise and acoustic reflection characteristics has become the main measure for underwater body acoustic stealth. Reducing self-radiated noise and acoustic reflection characteristics is a systematic project that requires overall acoustic design. As the outermost acoustic protection layer of underwater moving bodies, the acoustic covering layer usually has the functions of sound absorption, sound insulation, vibration suppression or impact resistance, and is currently the only key technology that can effectively resist active and passive detection at the same time.

Acoustic coverings usually contain various cavity structures such as spherical and cylindrical cavities, or viscoelastic composite structures containing heavy proton scatterers such as local resonance units. It also has other properties such as sound insulation and vibration reduction. The horizontally arranged honeycomb cavity covering layer has the characteristics of good sound insulation and impact resistance, which can not only reduce the external radiation of its own noise, but also improve the safety performance of underwater structures under instantaneous impact conditions to a certain extent. Compared with traditional spherical and cylindrical covering layers, the horizontally arranged honeycomb cavity covering layer also has good static pressure deformation resistance.

Contents of the invention

The technical problem to be solved by the present invention is to provide a horizontally arranged honeycomb cavity structure acoustic covering layer, which can effectively improve the performance of vibration suppression and sound insulation, and also has a certain sound absorption performance and impact resistance, and can effectively reduce the underwater The target strength and radiation noise of the structure play an important role in improving the stealth ability of the underwater structure.

The present invention is achieved through the following technical solutions:

The present invention is such an acoustic covering layer of honeycomb cavity structure, which comprises a damping layer, which contains periodically horizontally arranged honeycomb cavities, the damping layer comprises a rubber layer or a polymer resin layer, and the center line of the honeycomb cavity Perpendicular to the direction of propagation of elastic or acoustic waves.

Wherein, the section of the acoustic covering layer of the honeycomb cavity structure is any one of the following three arrangements:

(a) All honeycomb cavities have the same cross-sectional area;

(b) The cross-sectional area of the honeycomb cavity in each layer is the same, and the cross-sectional area of the honeycomb cavity between different layers changes gradually along the propagation direction of the elastic wave or sound wave;

(c) The cross-sectional area of each layer of honeycomb cavities is the same, and the cross-sectional surfaces of two adjacent rows of honeycomb cavities change periodically.

Owing to comprising honeycomb cavity structure in the present invention, from macroscopical point of view, be to have changed the group velocity (energy propagation velocity) and equivalent elastic modulus of cover layer, these changes and structure parameter (honeycomb cavity unit wall thickness, included angle) etc.) are related to the material parameters of the rubber or polymer resin itself, and determine the vibration suppression and sound insulation capabilities of the covering layer.

The invention has the advantage of flexible design, and can design covering layers with different bandwidths according to requirements.

Description of drawings

Fig. 1 is a three-dimensional schematic diagram of the acoustic covering layer of the honeycomb cavity structure of the present invention, and the size of the honeycomb cavity is uniform.

Fig. 2 is a schematic cross-sectional view of the acoustic covering layer of the honeycomb cavity structure of the present invention.

Fig. 3 is a three-dimensional schematic diagram of the acoustic covering layer of the honeycomb cavity structure of the present invention, and the honeycomb cavities are arranged in a layered and gradual manner.

Fig. 4 is a three-dimensional schematic diagram of the acoustic covering layer of the honeycomb cavity structure of the present invention, and the honeycomb cavities are in a form of periodic staggered arrangement.

Fig. 5 is a schematic diagram of multiple reflections of elastic waves or acoustic waves propagating in a honeycomb cavity unit.

Fig. 6 is a schematic diagram of the waveform conversion of elastic waves or acoustic waves propagating in the honeycomb cavity unit.

detailed description

The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

First, the mechanism of the present invention to isolate and dissipate vibrational elastic wave or acoustic wave energy is briefly described as follows:

(1) Since there are a large number of honeycomb cavities in the covering layer, the air impedance in the cavity is very different from the impedance of the base material of the covering layer, and the impedance mismatch effect causes a part of the elastic wave or sound wave to be isolated during the propagation process;

(2) The elastic wave or sound wave propagates to the corner of the honeycomb cavity structure, and the elastic wave or sound wave is reflected due to the discontinuity of the structure (Fig. 5), and the continuous reflection increases their propagation path in the covering layer. It means that more vibration or sound wave energy is consumed;

(3) There is a small transverse vibration displacement in the direction perpendicular to the propagation of the elastic wave or sound wave (Figure 6), that is, part of the longitudinal wave is transformed into a shear wave, which is more easily consumed in rubber materials or polymer resin materials. The joint effect of these mechanisms improves the vibration suppression and sound insulation ability of the honeycomb cavity structure covering layer.

Example 1:

As shown in Figure 1 and Figure 2, the center line of the honeycomb cavity is arranged parallel to the surface of the covering layer, and the matrix material is rubber or polymer resin. In this embodiment, if different structural parameters are selected, different vibration suppression and sound insulation functions can be obtained. If a smaller honeycomb cavity size (or a smaller cavity volume percentage) is used, better sound absorption performance and certain sound insulation performance can be obtained, and it has certain pressure resistance and deformation resistance; if a larger honeycomb cavity size is used The honeycomb cavity size (or a larger cavity volume percentage) can obtain better sound insulation, impact resistance and certain sound absorption performance.

Example 2:

As shown in Figure 3, in this embodiment, the arrangement form of the honeycomb cavities is a layered and gradual form, and the ones near the outside of the covering layer (near the side of the water medium) are set to a smaller honeycomb cavity size (or a smaller cavity size). Cavity volume percentage), on the inner side of the cover layer (near the structure side) set to a larger honeycomb cavity size (or larger cavity volume percentage), the size of the honeycomb cavity in the middle part of the cover layer changes from small to large. The base material is rubber or polymer resin. This embodiment has good sound absorption performance and sound insulation performance at the same time, and also has good impact resistance performance.

Example 3:

As shown in FIG. 4 , in this embodiment, the arrangement of the honeycomb cavities is a periodic staggered arrangement of large and small cavities. The base material is rubber or polymer resin. This embodiment has good sound insulation performance and impact resistance performance, and at the same time, it has better resistance to compressive deformation.

Certainly, the above are only specific application examples of the present invention, and there are other implementation modes in the present invention, and all technical solutions formed by equivalent replacement or equivalent transformation all fall within the scope of protection required by the present invention.

Claims (2)

1. A honeycomb cavity structure acoustic covering layer, which includes a damping layer, is characterized in that: the damping layer contains periodically horizontally arranged honeycomb cavities, the damping layer comprises a rubber layer or a polymer resin layer, and the center of the honeycomb cavity The line is perpendicular to the direction of propagation of the elastic or acoustic wave. 2. The honeycomb cavity structure acoustic covering layer according to claim 1, characterized in that: the section of the honeycomb cavity structure acoustic covering layer is any one of the following three arrangements: (a) All honeycomb cavities have the same cross-sectional area; (b) The cross-sectional area of the honeycomb cavity in each layer is the same, and the cross-sectional area of the honeycomb cavity between different layers changes gradually along the propagation direction of the elastic wave or sound wave; (c) The cross-sectional area of each layer of honeycomb cavities is the same, and the cross-sectional surfaces of two adjacent rows of honeycomb cavities change periodically.