Low-frequency vibration reduction and isolation structure design of co-vibration type vector hydrophone

Abstract

The invention provides a low-frequency vibration reduction and isolation structure design of a co-vibration type vector hydrophone. The low-frequency vibration reduction and isolation structure design comprises the co-vibration type vector hydrophone, a vibration reduction suspension system, a vibration isolation system, a signal acquisition system and a signal transmission system. Aiming at how to avoid the influence of cable shaking and platform vibration on the low-frequency receiving performance of the co-vibration type vector hydrophone, the vibration conduction of the cable and the platform to the vector hydrophone is reduced through the structural design of oil-filled packaging and multi-layer vibration isolation, so that the low-frequency vibration reduction and isolation of the vector hydrophone are realized.

Description

Technical Field

[0001] The invention relates to the field of underwater acoustic detection, and in particular to the design of a vibration reduction and isolation structure of a vector hydrophone, in particular to the design of a low-frequency vibration reduction and isolation structure of a homophonic vector hydrophone. Background Art

[0002] The vector hydrophone is a composite of the traditional sound pressure hydrophone and the particle velocity hydrophone. It can synchronously and co-pointly measure the three orthogonal components of the sound pressure and particle velocity at a point in the sound field space, which not only helps to improve the performance of the hydroacoustic system, but also broadens the signal processing space. The vector hydrophone has many advantages such as good low-frequency directivity and strong ability to suppress isotropic noise, and also provides new ideas and methods for solving hydroacoustic problems. With the increasing maturity of vector hydrophone technology and driven by military needs, vector hydrophone technology has been widely used in various fields of hydroacoustics. It has become one of the most active research directions in the hydroacoustic community. At present, there are two types of vector hydrophones with the most extensive engineering application technology in China, one is the co-vibration vector hydrophone and the other is the pressure difference vector hydrophone. Among them, the pressure difference vector hydrophone has a simple working principle and structural design, mature technology, and can be rigidly connected during application without considering the influence of the suspension method, but generally has a narrow working frequency band, low low-frequency sensitivity, and low signal-to-noise ratio under weak signals. In practical applications, it is limited by its size, working frequency band and directivity. The isochronous vector hydrophone can directly obtain the vibration information of water particles in the underwater sound field, and has high low-frequency sensitivity, small fluctuations in the sensitivity frequency response within the working frequency range, good symmetry of the directivity diagram, high resolution, small size, and light weight. It has high accuracy and reliability in measuring underwater acoustic information. In practical engineering applications, the isochronous vector hydrophone is required to be in a free suspension state in the fluid medium under the condition of elastic element suspension. In order not to affect the measurement performance of the vector hydrophone, the suspension device needs to meet some basic requirements. First of all, it is required to fix the vector hydrophone in a certain equilibrium position and ensure the stability of the movement direction, but at the same time, it can allow the hydrophone to move freely under the action of sound waves; secondly, the hydrophone can work normally within the working frequency band, the received signal is not distorted, and the resonant frequency of the suspension system must be lower than the lower limit of the working frequency of the vector hydrophone; finally, the suspension device must be able to effectively isolate the structural vibration of the external platform or frame, and also withstand the impact of external movement. Therefore, it is very important to study the suspension elastic element-vector hydrophone system for the application of the co-vibration vector hydrophone. At present, scholars' research work on the influence of suspension mode and suspension device on the acoustic reception performance of the vector hydrophone is basically analyzed under the condition that the underwater acoustic system platform is fixed, and then the motion equation of the vector hydrophone and the influence of the suspension device on the acoustic reception performance are obtained. The influence of the platform vibration on the performance of the vector hydrophone receiving acoustic signals is not considered, that is, the vibration isolation between the hydrophone system and the installation platform. The external vibration excitation is an interference source that cannot be ignored in the low-frequency and very low-frequency bands. Therefore, it is necessary to seek an optimized vibration reduction suspension device and a vibration isolation device between the hydrophone system and the installation platform, and study its vibration reduction and isolation capabilities for external vibrations, especially the vibration reduction and isolation capabilities in the low-frequency band. Finally, from the acoustic perspective, the influence of the vibration reduction and isolation system on the vector hydrophone receiving acoustic signals is obtained, which has a great guiding significance for engineering practice.

[0003] BE-10 rubber vibration isolator has the following advantages. First, BE rubber vibration isolator is made of metal and rubber composite. The metal surface is completely covered with rubber, which can prevent metal corrosion. It is resistant to oil, seawater, salt spray and sunlight, and can meet various water acoustic test environmental conditions such as land and ship use. Secondly, BE rubber vibration isolator has low natural frequency, suitable damping ratio, higher lateral stiffness than vertical stiffness, and is suitable for horizontal, inverted and side hanging installation. When used horizontally, it has good lateral stability. Finally, when BE rubber vibration isolator is subjected to a large impact, it can automatically limit protection, and at the same time, it has a strong ability to suppress the resonance peak. The self-vibration caused by transient impact response and transient over-working conditions can disappear quickly, which can ensure that the equipment will not shake. Studies have shown that rubber vibration isolator has good vibration reduction and isolation performance for water acoustic sensors, and the impact resistance of the two-stage vibration reduction system is better than that of the single-stage vibration reduction system. Summary of the invention

[0004] The purpose of the present invention is to provide a low-frequency vibration reduction and isolation structure design for a co-oscillating vector hydrophone. The traditional way to suspend a vector hydrophone is to directly suspend the vector hydrophone on a frame with a rubber rope or spring during testing. Experiments have shown that when the hydrophone cable is impacted by water flow, the hydrophone will be driven to move at the same time, which has a great impact on the hydrophone test. In order to solve this problem, the present invention intends to suspend the vector hydrophone on a frame with a rubber rope, and then place it in an oil-filled sound-permeable tube to reduce the impact of the cable on the performance of the hydrophone, achieve hydrophone vibration reduction, and facilitate system installation. In addition, the design of the oil-filled structure can achieve high pressure resistance by balancing internal and external pressures. At the same time, the present invention intends to use rubber vibration isolators for secondary vibration isolation design to effectively isolate platform vibration, improve external vibration interference, and achieve low-frequency signal acquisition.

[0005] The vibration reduction and isolation structure design of the low-frequency isochronous self-contained vector hydrophone mainly includes the isochronous vector hydrophone, the vibration reduction suspension system, the vibration isolation system, the signal acquisition system and the signal transmission system.

[0006] The isochronous vector hydrophone may be a velocity isochronous vector hydrophone or an acceleration isochronous vector hydrophone, and is used to acquire water acoustic signals.

[0007] The vibration reduction suspension system comprises an elastic suspension member, a rigid suspension bracket and a sound-permeable deflector.

[0008] The vibration isolation system may be a two-stage vibration isolation system consisting of a rubber vibration damper and a rigid metal plate.

[0009] The signal acquisition system may be composed of a metal or non-metal pressure-resistant shell with a built-in preamplifier module and an acquisition module.

[0010] The elastic hanging member may be a hanging member with a low elastic coefficient, such as a rubber rope and a spring, and is used for hanging and connecting the hydrophone.

[0011] The rigid suspension bracket may be a metal frame with high rigidity and mass, and is used to suspend the vector hydrophone.

[0012] The signal transmission system is an underwater pluggable watertight connector that can withstand a certain water pressure.

[0013] In the above technical solution, preferably, the elastic suspension member is a nitrile rubber O-ring.

[0014] In the above technical solution, preferably, the air guide cover is a polyurethane sound-transmitting packaging shell.

[0015] In the above technical solution, preferably, the rubber vibration damper is a BE type rubber vibration damper.

[0016] In the above technical solution, preferably, the metal of the pressure-resistant shell of the collection cabin can be titanium alloy, stainless steel or beryllium bronze. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the present invention.

[0018] In the figure: 1-isotropic vector hydrophone, 2-vibration reduction suspension system, 3-vibration isolation system, 4-signal acquisition system and 5-signal transmission system. DETAILED DESCRIPTION

[0019] According to the technical solution of the present invention, without changing the essential spirit of the present invention, those skilled in the art can change or replace a variety of structural modes and implementation modes. Therefore, the following specific implementation modes and drawings are only exemplary descriptions of the technical solution of the present invention, and should not be regarded as the whole of the present invention or as a limitation or restriction to the technical solution of the present invention.

[0020] like Figure 1 As shown, the vector hydrophone is suspended on the rigid suspension bracket at eight points through elastic suspension parts, and the mounting bracket is installed in the sound-transmitting guide cover, which is filled with methyl silicone oil. The fixing flange is installed, and 4 BE-10 rubber vibration dampers are installed under the flange. The bottom of the 4 vibration dampers is fixedly installed on the rigid fixing plate, and 4 more rubber vibration dampers are installed between the rigid fixing plate and the collection cabin.

[0021] The beneficial effects of the present invention are:

[0022] 1. The present invention provides a low-frequency vibration reduction and isolation structure design for a co-oscillation type vector hydrophone, which avoids the hydrophone from moving simultaneously when the hydrophone cable is impacted by water flow, etc., which has a great impact on the hydrophone test.

[0023] 2. The present invention provides a two-stage rubber vibration isolation design, which can effectively reduce the impact of the installation platform vibration on the hydrophone test.

[0024] The low-frequency vibration reduction and isolation structure design of the present invention can be widely applied to isotropic vector hydrophones used in the fields of underwater target detection and ocean monitoring, and has high practical value.

Claims

1. A low-frequency vibration reduction and isolation structure design of a homogeneous vector hydrophone is achieved through the design of oil-filled package suspension and multi-layer rubber vibration isolator vibration isolation.

2. The low-frequency vibration reduction and isolation structure of the isotropic vector hydrophone according to claim 1 is characterized in that The vector hydrophone is oil-filled and packaged in a sound-transmitting guide cover.

3. The low-frequency vibration reduction and isolation structure of the isotropic vector hydrophone according to claim 1 is characterized in that The rubber vibration damper is a BE type rubber vibration damper.

4. The low-frequency vibration reduction and isolation structure of the isotropic vector hydrophone according to claim 1 is characterized in that The vibration isolation design adopts multi-layer rubber vibration dampers to achieve low-frequency vibration isolation.

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