CN102980646B - Solid/fluid interfacial wave detecting device and method based on vector hydrophone - Google Patents

Abstract

The invention discloses a detection device and a detection method of a fluid-solid interface wave, belonging to the technical field of ultrasonic detection and analysis. The signal excitation module generates a square wave pulse signal, the excitation signal transmitting module generates an interface wave, and the interface wave propagates along the interface. The vector hydrophone in the signal receiving module directly receives the interface wave signal in the water close to the interface, and the vector hydrophone is used The vector information of the sound field can be obtained, and the anti-noise interference ability and line spectrum detection ability of the system can be improved. The hydrophone is fixed on a cross bracket composed of a double-axis screw slide table, and the precise movement is realized through an external control circuit. Finally, the signal acquisition module transmits the collected waveform data to the computer terminal for data processing and display. The method of the invention is flexible and convenient, can realize fluid-solid interface wave detection and array reception at any position, has a large amount of data collection, and can greatly improve detection accuracy and reliability through later signal processing.

Description

Fluid-solid interface wave detection device and detection method based on vector hydrophone

technical field

The invention relates to a detection device and a detection method for fluid-solid interface waves, belonging to the technical field of ultrasonic detection and analysis.

Background technique

The development of acoustic technology provides an effective means for non-destructive evaluation, stress detection and defect detection. Because the fluid-solid interface wave has the characteristics of large amplitude, small propagation loss, and small dispersion, the propagation in the medium can reflect many information in various fluid-solid media, such as the permeability, density, smoothness, and fracture characteristics of the solid medium. Liquid concentration, impurity content, etc. In recent years, the application of fluid-solid interface waves in geophysics, non-destructive testing and other fields has aroused widespread interest among researchers, and is currently widely used in dam monitoring, geological exploration, sediment content detection, etc. in engineering applications.

The interface wave mainly refers to the wave propagating along the fluid-solid interface, and the interface wave mainly existing in the fluid-solid interface refers to the scholte wave and leaky raleigh wave. Due to the advantages of large amplitude, high energy, no low-frequency cut-off frequency, propagation velocity and attenuation are closely related to the shear wave characteristics of sedimentary layers, Scholte has become a research hotspot in the field of inverse analysis of medium structure properties. At present, the common excitation and detection methods of fluid-solid interface waves are:

(1) The laser pulse emitted by the pulsed laser is focused into a line source by a cylindrical lens, and then vertically incident on the solid surface to excite surface waves, which are transformed at the fluid-solid interface to form fluid-solid interface waves. The optical interference displacement vibration receiving system is used at different distances from the excitation source to receive the propagating and arriving interface waves in real time. Such as the invention patent - a micro-scale interface wave excitation method and device (application number: 02112787.5).

(2) By half-immersing the solid in the liquid, the solid and the liquid form a certain angle to obtain a suitable incident angle. A transducer is used to excite the interface wave on the solid surface exposed to the liquid, and Rayleigh waves are first formed on the air-solid surface. When the rayleigh wave propagates to the surface where the air is replaced by liquid, part of the wave is reflected back, and part of the wave is converted into a scholte wave. And leaky rayleigh waves. A receiving transducer is placed at the other end of the solid submerged in the liquid to receive the interface wave signal.

(3) Use the ultrasonic angled probe to directly excite the interface wave on the solid surface. Since the incident wave emitted by the ultrasonic angled probe forms a precise incident angle on the solid surface, Rayleigh waves and Scholte waves can be directly excited according to the waveform conversion. The propagating signal is directly received at the fluid-solid interface by the receiving transducer.

All the above-mentioned methods can achieve the purpose of detecting the fluid-solid interface wave under certain circumstances to a certain extent, but limited by the detection conditions, there are problems such as expensive detection equipment, low detection efficiency, and single detection method.

Contents of the invention

The object of the present invention is to provide a device and a detection method for detecting interface waves with flexible receiving methods and high automation.

The invention adopts the vector hydrophone to directly receive the interface wave signal in water, does not need to install receiving equipment at the fluid-solid interface, and the detection method is relatively simple. Aiming at the shortcoming that scalar hydrophones or traditional detection methods can only accept a single signal, the use of vector hydrophones can simultaneously measure the orthogonal components reflecting sound pressure and mass vibration velocity, reflecting complete sound field information. The processing module can obtain more reliable underwater acoustic information. Compared with the traditional single sound pressure information processing system, it has good anti-coherent interference ability and line spectrum detection ability, and the detection reliability is high. The invention can realize multi-point measurement or array reception through the movement of the vector hydrophone, has large amount of data collection, strong data processing capability and greatly improved measurement accuracy. At the same time, the external control circuit of the present invention directly controls the movement of the vector hydrophone, has a high degree of automation, and can adjust the height and position of the hydrophone according to actual conditions, and is more suitable for extensive promotion in actual engineering interface wave detection.

At the fluid-solid interface, when the fluid side and the solid side are semi-infinite space media, the displacement of the plane wave should be zero, so the displacement potential function of the plane wave propagating in the fluid-solid interface can be written as:

ψ2＝B2exp[-b2ky+ik(x-ct)] (3)

In formula (1) (2) (3), is the longitudinal wave potential function in the fluid medium, there is no shear wave in the fluid, so there is no shear wave potential function. and ψ are the longitudinal wave potential function and shear wave potential function in the solid medium respectively, A ₁ , A ₂ , B ₂ are arbitrary coefficients, k is the propagating wave number (k=ω/c), and c is the phase velocity. $a_1=\sqrt{1-c^2/c_{l1}^2};$ $a_2=\sqrt{1-c^2/c_{l2}^2};$ $b_2=\sqrt{1-c^2/c_{t2}^2};$ $c_{l1}=\sqrt{\frac{{\mathrm{\λ}}_1}{{\mathrm{\ρ}}_1}};$ $c_{l2}=\sqrt{\frac{{\mathrm{\λ}}_2+2{\mathrm{\μ}}_2}{{\mathrm{\ρ}}_2}}$ and $c_{t2}=\sqrt{\frac{{\mathrm{\μ}}_2}{{\mathrm{\ρ}}_2}}$ are the longitudinal and shear wave velocities in the solid medium, respectively. λ and μ are the Lamé constants of the medium, and ρ is the density. The subscripts 1 and 2 of the parameters in the above formulas represent fluid and solid media, respectively.

Combined with the boundary conditions that should be satisfied when the plane wave propagates at the fluid-solid interface:

(1) Continuous condition of interface normal displacement: u _y1 = u _y2

(2) Interface normal stress condition: δ _y1 = δ _y2

(3) Interface tangential stress condition: τ _xy1 = τ _xy2 = 0

According to the potential function and the relationship between displacement and stress and the potential function, the characteristic equation of the fluid-solid interface wave can be obtained as:

${<span\; class="notranslate">\; [</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; c</span>}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; ]</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 4</span>}\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; c</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; l</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; \&times;</span>\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; c</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; \&rho;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; \&rho;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; c</span>}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 4</span>}}\frac{\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; c</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; l</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}}{\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; c</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; l</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}$

From the above derivation of the characteristic equation of the fluid-solid interface wave, it can be seen that the fluid-solid interface wave propagates in two semi-infinite media, the reflection and refraction of the interface are not considered in the propagation process, and it propagates in the form of a plane wave. However, in reality, it is impossible to achieve infinite solid and liquid. Therefore, when designing this detection device, the influence of reflection and refraction at the boundary should be minimized. Cutting the solid into a thin plate and standing it in water can approximate the thickness of the solid side. is larger than the wavelength, and when the piezoelectric ceramic sheet is sufficiently narrow, it is considered that the reflections from the two boundaries will be ignored, so this device does not need to convert other waves to directly generate interface waves.

In order to achieve the above object, the technical scheme adopted in the present invention is:

The signal transmitting module and the signal receiving module are respectively placed at both ends of the solid interface. The signal excitation module generates a square wave pulse signal to stimulate the signal transmitting module to generate interface waves. The interface waves propagate along the interface and are received by the signal receiving module. The signal receiving module is composed of The vector hydrophone directly receives the interface wave signal in the water close to the interface, and the vector information of the sound field can be obtained by using the vector hydrophone, which improves the system's anti-noise interference ability and line spectrum detection ability. The hydrophone is fixed on a cross bracket composed of a double-axis screw slide table, and the precise movement of the hydrophone is realized through an external control circuit. The bracket can also fix multiple hydrophones at the same time to realize the array reception of the hydrophones. Finally, the signal acquisition module transmits the collected waveform data to the computer terminal for data processing and display. The method of the invention is flexible and convenient, can realize fluid-solid interface wave detection and array reception at any position, has a large amount of data collection, and can greatly improve detection accuracy and reliability through later signal processing.

A detection device based on a fluid-solid interface wave of a vector hydrophone, characterized in that it comprises

an excitation signal module for generating a pulse excitation signal;

A signal transmitting module that generates interface waves under the excitation of the excitation signal module;

The signal receiving module includes a vector hydrophone, and directly receives the interface wave signal emitted by the signal transmitting module in water;

A signal acquisition module, which collects the signal received by the signal receiving module;

An external control circuit module controls the movement of the vector hydrophone;

The signal processing and display module processes and displays the waveform of the signal transmitted by the signal acquisition module.

The excitation signal module includes a square wave pulse signal generation module with a signal generator as the core, and a power amplification module with a high-frequency power amplifier as the core, which can produce square wave pulse signals with variable pulse width and frequency; the square wave The pulse signal generation module is connected with the power amplification module, and the power amplification module amplifies the power of the square wave pulse signal generated by the square wave signal generation module.

In the signal transmitting module, the piezoelectric ceramic sheet is used as the transmitting transducer to excite the interface wave signal, and a layer of epoxy resin is coated around the piezoelectric ceramic sheet transducer to prevent energy radiation and conduction. The piezoelectric ceramic sheet is fixed on both ends of the solid side of the interface with AB glue, and the piezoelectric ceramic sheet is perpendicular to the two sides adjacent to the interface when fixed.

The signal transmitting module is fixedly arranged at one end of the solid side of the fluid-solid interface and is perpendicular to the two sides adjacent to the interface.

The signal receiving module includes a vector hydrophone for receiving underwater acoustic signals and a cross double-axis screw slide table for suspending the vector hydrophone. Compared with the traditional scalar hydrophone, the vector hydrophone can obtain more sound field information, Improve the reliability of signal processing. According to the vibration pickup condition of the vector hydrophone: when the condition ka<<1 is met (where k represents the wave number, a is the radius of the hydrophone), and the average density of the vector hydrophone is close to the density of the water medium, the vector water The amplitude of the vibration velocity of the hearing instrument is the same as that of the water particle, and the phase tends to zero. Therefore, in the selection of the vector hydrophone, the overall density should be slightly larger than that of the liquid medium, and the size should be smaller than the wavelength of the measured sound wave. The vector hydrophone is suspended in the liquid perpendicular to the fluid-solid interface and close to the fluid-solid interface. The height of the cross double-axis screw slide table should not be too high, slightly higher than the water surface, which can prevent the shaking of the hydrophone during the movement. The support of the cross double-axis screw slide table should reserve multiple hanging devices and can hang multiple pieces of hydrophone equipment to realize the reception of the hydrophone array.

The external control circuit module controls the two-axis screw slide table to drive the vector hydrophone to move; the external control circuit module is composed of two sets of devices with the same structure, which respectively control the vector hydrophone in the X-axis and Y-axis directions Accurate movement; each set of devices is driven by a stepping motor to drive the lead screw to move the slide table.

The signal acquisition module includes an integrated operational amplifier, a high-speed A/D conversion module, an FPGA high-speed control module and a computer terminal. Among them, the high-speed A/D conversion module directly collects the signal from the operational amplifier through a wired method, and digitizes the analog signal; the FPGA high-speed control module controls the high-speed A/D conversion module through the IO port and converts the high-speed A/D conversion module. The data is stored in the SRAM (Static Random Access Memory) of the computer terminal; the FPGA high-speed control module reads out the data in the SRAM and transmits it to the computer through the RS232 serial port; the host computer of the computer terminal directly reads the data and performs post-processing Algorithmic processing and reproduction work.

The signal processing and display module is computer terminal processing, including a wave velocity shaping algorithm module for optimizing hydrophone signals, a processing module and a display module for multiplying other underwater acoustic information. In this way, the ability and speed of data processing can be improved, the power consumption and volume of the detection device can be reduced, and the reliability of detection can be improved.

A method for detecting fluid-solid interface waves based on vector hydrophones, characterized in that it comprises the following steps:

(1) Cut the solid into cuboid thin slices, use the surface formed by the length and thickness of the cuboid as the bottom surface, and stand the solid block in the water tank;

(2) The piezoelectric ceramic sheet is made into a narrow-band cuboid as the transmitting transducer, and the ratio of the length and width of the piezoelectric ceramic sheet is 4:1; the piezoelectric ceramic sheet is placed in the signal transmitting module, and the piezoelectric ceramic sheet The length is parallel to the narrow side of the fluid-solid interface; the signal transmitting module is fixed at one end of the solid side of the fluid-solid interface, and the piezoelectric ceramic sheet is perpendicular to the two sides adjacent to the interface during the fixing process; A layer of epoxy resin is coated around the piezoelectric ceramic sheet;

(3) Install the cross double-axis screw slide table bracket on both sides of the solid, and the top of the bracket is higher than the liquid level in the tank; adjust the center position of the X-axis and Y-axis so that it is directly above the fluid-solid interface, And the distance from the signal transmitting module to one wavelength;

(4) Suspend one or more vector hydrophones on the double-axis screw slide table, adjust the position of the vector hydrophones, so that the vector hydrophones are vertically suspended in the liquid close to the interface, close to the interface but not Fitted with solid to ensure the free movement of the hydrophone;

(5) Adjust the pulse width of the square wave signal output by the excitation signal module, so that the pulse width of the excitation signal is 1/2 of the rated frequency of the piezoelectric ceramic sheet, so that the amplitude change of the detection signal reaches the maximum value;

(6) The excitation signal transmitting module generates a boundary wave signal by the excitation signal module;

(7) The vector hydrophone receives the boundary wave signal transmitted by the signal transmitting module;

(8) The signal acquisition module is controlled by the host computer software to collect the signal received by the vector hydrophone, and then the computer terminal processes the collected signal and displays it on the display of the computer terminal;

(9) Control the movement of the dual-axis screw slide table through an external control circuit to drive the movement of the vector hydrophone. After the motion of the vector hydrophone stops in the water, repeat the process of steps (5)-(8).

The beneficial effect that the present invention reaches:

The invention provides a fluid-solid interface wave detection device and detection method based on a vector hydrophone. The propagation of the wave at the fluid-solid interface is mainly due to the coupling of acoustic waves at the fluid-solid interface. In the waveform of the fluid-solid interface wave, the energy of the Leaky Rayleigh wave is mainly concentrated on the solid surface, but it continuously radiates energy into the fluid during the propagation process; while the energy of the Schotle wave is mainly concentrated in the fluid near the fluid-solid interface, with the largest amplitude , The dispersion is small; therefore, there are a large number of acoustic wave signals in the liquid near the fluid-solid interface, and the detection of interface wave signals can be achieved by directly receiving vector hydrophones in water. Since the vector hydrophone can obtain the sound pressure at a point in the sound field and the orthogonal component of the particle vibration, more complete sound field information can be obtained through later signal processing than the scalar hydrophone or a single sound pressure detection system. At the same time, the system High anti-coherent interference ability and line spectrum detection ability can be obtained. The device does not need to install equipment on the solid side in advance or preset a small hole for placing the receiving transducer, which is simple and convenient. According to the propagating characteristic that the interface wave decays exponentially along the direction perpendicular to the interface between the two media, and the energy is mainly concentrated in a wavelength range of the interface, the invention can flexibly move the placement position of the vector hydrophone to facilitate the detection of the optimal signal. At the same time, after one excitation, the position of the hydrophone is adjusted for the next reception, which realizes the signal reception in motion and reflects the propagation characteristics of interface wave signals at different time points. The invention can form a hydrophone array by arranging a plurality of hydrophones, so as to improve the receiving signal power. The signal receiving method of the invention is flexible, can realize multi-point detection and array reception, improves the detection precision of interface wave, has strong data processing ability and high reliability.

The invention controls the fixed-point movement of the hydrophone through an external control circuit, accurately locates the distance positions of different detection points, and has a high degree of automation of the equipment. At the same time, the position and height of the hydrophone can be adjusted according to the actual situation, and the flexibility is high, which is beneficial to this invention. Promotion and use of inventions in practical applications.

Description of drawings

Fig. 1 is a schematic diagram of the detection device of the present invention.

Detailed ways

The present invention will be further described below in conjunction with accompanying drawing. The following examples are only used to illustrate the technical solution of the present invention more clearly, but not to limit the protection scope of the present invention.

As shown in Figure 1, the fluid-solid interface wave detection device of the present invention mainly consists of 6 parts: excitation signal module 1; signal transmitting module 2; signal receiving module 3; signal acquisition module 4; signal processing display module 5; external control circuit Module 6. The signal transmitting module 2 uses a piezoelectric ceramic sheet as a transmitting transducer to generate interface wave signals. In order to ensure a large-amplitude interface wave signal, the excitation signal module 1 generates a square wave pulse signal with variable pulse width and frequency, and adjusts the pulse width to 1/2 of the rated frequency of the piezoelectric ceramic sheet. The selection of the piezoelectric ceramic sheet should not be too thick, and it is fixed on the two ends of the solid 101 side of the interface 102 with AB glue, and during the fixing process, it is perpendicular to the two sides adjacent to the interface, and finally the fixed pressure A layer of epoxy resin is coated around the electric ceramic sheet to tightly surround the piezoelectric ceramic sheet to prevent conduction and reduce energy radiation.

The signal receiving module 3 includes a vector hydrophone, and the vector hydrophone whose size and overall density meet the system requirements is selected. The principle is: the overall density is slightly larger than the liquid medium, and the size is smaller than the wavelength of the measured sound wave. The installation position of the vector hydrophone is to hang vertically in the liquid 103, and the height is as close as possible to the fluid-solid interface 102 but not completely fitted, which can ensure the flexible movement of the hydrophone. The cross double-axis screw slide table 8 bracket 9 for suspending the hydrophone is installed on both sides of the solid to ensure the precise movement of the vector hydrophone in the X-axis and Y-axis directions under the premise of stability. The height of the cross double-axis lead screw slide table 8 should not be too high, and the shaking of the hydrophone during the movement should be prevented.

The signal acquisition module 4 includes an integrated operational amplifier, a high-speed A/D conversion module, an FPGA high-speed control module and a computer terminal. The interface wave signal is collected through the upper computer control signal acquisition module of the computer terminal, and the collected data is saved in the SRAM of the computer.

The signal processing and display module 5 processes the collected data and then displays the processing results through the computer monitor. Using the computer for data processing can improve the data processing speed and processing capacity, and reduce the power consumption of the detection device.

The external control circuit module 6 controls the two-axis screw slide table 8 to drive the vector hydrophone 3 to move; the external control circuit module is composed of two sets of devices with identical structures, which respectively control the movement of the vector hydrophone in the X-axis and Y-axis directions. Precise movement; each set of devices is driven by a stepping motor to drive the lead screw to move the slide table.

The detection method of the fluid-solid interface wave based on the vector hydrophone of the present invention, the specific implementation method is as follows:

1) The solid 101 is cut into cuboid thin slices, and the thickness is not too large, which can minimize the reflection and refraction of waves propagating in the solid. With the face formed by the long and thickness sides of the cuboid as the bottom surface, the solid block is erected in the water tank 7;

(2) The piezoelectric ceramic sheet is made into a narrow-band cuboid as the transmitting transducer in the signal transmitting module 2, the ratio of length to width is about 4:1, and the thickness is as thin as possible. The piezoelectric ceramic sheet is arranged in the signal transmitting module, and the length of the piezoelectric ceramic sheet is parallel to the narrow side of the fluid-solid interface; the signal transmitting module 2 is fixed at one end of the solid side of the interface, and the piezoelectric The ceramic sheet is perpendicular to the two sides adjacent to the interface; a layer of epoxy resin is coated around the fixed piezoelectric ceramic sheet to tightly surround the piezoelectric ceramic sheet;

(3) Install the bracket 9 of the cross double-axis screw slide table, and the two load-bearing support columns of the bracket 9 are fixed on both sides of the solid 101 , and the top of the bracket 9 is higher than the liquid surface in the water tank 7 . Adjust the positions of the centers of the X-axis and the Y-axis so that they are directly above the fluid-solid interface 102 and about one wavelength away from the signal transmitting module 2 .

(4) Hang one or more vector hydrophones on the double-axis screw slide table 8, and adjust the position of the vector hydrophones so that the vector hydrophones are vertically suspended in the water close to the interface 102, as close as possible to the interface 102 but not completely fit with the solid to ensure the free movement of the hydrophone;

(5) Adjust the pulse width of the square wave signal output by the excitation signal module 1, so that the pulse width of the excitation signal is 1/2 of the rated frequency of the piezoelectric ceramic sheet, so that the amplitude change of the detection signal reaches the maximum value;

(6) The interface wave signal is generated by the excitation signal module 1, the excitation signal transmitting module 2, that is, the piezoelectric ceramic sheet;

(7) The vector hydrophone in the signal receiving module 3 receives the interface wave signal emitted by the piezoelectric ceramic sheet in the signal transmitting module 2;

(8) The host computer software controls the signal acquisition module to collect the signal received by the signal receiving module 2, and then the computer terminal processes the collected signal and displays it on the computer terminal display.

(9) Control the movement of the two-axis silk slide table 8 through an external control circuit to drive the movement of the vector hydrophone. After the motion of the vector hydrophone stops in the water, repeat the process of (5)-(8). If multiple hydrophones are used to form a hydrophone array to receive interface wave signals, a beamforming algorithm module is added in the later signal processing process.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the technical principle of the present invention, some improvements and modifications can also be made. It should also be regarded as the protection scope of the present invention.

Claims (7)

1. A detection device based on the fluid-solid boundary wave of the vector hydrophone, it is characterized in that, comprising an excitation signal module for generating a pulse excitation signal; A signal transmitting module that generates interface waves under the excitation of the excitation signal module; The signal receiving module includes a vector hydrophone, and directly receives the interface wave signal emitted by the signal transmitting module in water; A signal acquisition module, which collects the signal received by the signal receiving module; An external control circuit module controls the movement of the vector hydrophone; The signal processing display module processes and displays the waveform of the signal transmitted by the signal acquisition module; The signal receiving module includes a vector hydrophone for receiving underwater acoustic signals and a cross double-axis screw slide table for suspending the vector hydrophone. The vector hydrophone is suspended in the liquid perpendicular to the fluid-solid interface and close to the fluid-solid interface. Interface; The external control circuit module controls the two-axis screw slide table to drive the vector hydrophone to move; the external control circuit module is composed of two sets of devices with the same structure, which respectively control the vector hydrophone in the X-axis and Y-axis directions Accurate movement; each set of devices is driven by a stepping motor to drive the lead screw to move the slide table. 2. the detection device based on the fluid-solid boundary wave of vector hydrophone according to claim 1, it is characterized in that, described excitation signal module comprises the square wave pulse signal generation module with signal generator as core, with high frequency The power amplifier is the core power amplification module; the square wave pulse signal generating module is connected with the power amplification module. 3. the detection device based on the fluid-solid boundary wave of vector hydrophone according to claim 1, is characterized in that, adopts piezoelectric ceramic chip to excite boundary wave signal as transmitting transducer in described signal transmitting module, and piezoelectric A layer of epoxy resin is coated around the ceramic disc transducer. 4. The detection device of the fluid-solid interface wave based on the vector hydrophone according to claim 1, wherein the signal transmitting module is fixedly arranged at one end of the solid side of the fluid-solid interface and perpendicular to the interface phase with the interface. adjacent two sides. 5. the detection device based on the fluid-solid boundary wave of vector hydrophone according to claim 1, is characterized in that, described signal acquisition module comprises integrated operational amplifier, high-speed A/D conversion module, FPGA high-speed control module and computer Terminal, the A/D conversion module is connected with the integrated operational amplifier, the FPGA high-speed control module is connected with the high-speed A/D conversion module through the IO port and connected with the computer terminal through the RS232 serial port. 6. the detection device based on the fluid-solid interface wave of vector hydrophone according to claim 1, is characterized in that, described signal processing display module is computer terminal processing, comprises the wave velocity shaping algorithm for optimizing hydrophone signal module and a processing module and a display module for multiplying other underwater acoustic information. 7. A method for detecting fluid-solid interface waves based on vector hydrophones, characterized in that it comprises the following steps: (1) Cut the solid into cuboid thin slices, use the surface formed by the length and thickness of the cuboid as the bottom surface, and stand the solid in the water tank; (2) The piezoelectric ceramic sheet is made into a narrow-band cuboid as the transmitting transducer, and the ratio of the length and width of the piezoelectric ceramic sheet is 4:1; the piezoelectric ceramic sheet is placed in the signal transmitting module, and the piezoelectric ceramic sheet The length is parallel to the narrow side of the fluid-solid interface; the signal transmitting module is fixed at one end of the solid side of the fluid-solid interface, and the piezoelectric ceramic sheet is perpendicular to the two sides adjacent to the fluid-solid interface during the fixing process; Coat a layer of epoxy resin around the fixed piezoelectric ceramic sheet; (3) Install the cross double-axis screw slide table bracket on both sides of the solid, and the top of the bracket is higher than the liquid level in the tank; adjust the center position of the X-axis and Y-axis so that it is directly above the fluid-solid interface, And the distance from the signal transmitting module to one wavelength; (4) Suspend one or more vector hydrophones on the double-axis screw slide table, adjust the position of the vector hydrophones, so that the vector hydrophones are vertically suspended in the liquid close to the fluid-solid interface, close to the fluid-solid interface The interface is not bonded to the solid to ensure the free movement of the hydrophone; (5) Adjust the pulse width of the square wave signal output by the excitation signal module so that the pulse width of the excitation signal is equal to the rated frequency of the piezoelectric ceramic sheet , so that the amplitude change of the detection signal reaches the maximum value; (6) The excitation signal transmitting module generates a boundary wave signal by the excitation signal module; (7) The vector hydrophone receives the boundary wave signal transmitted by the signal transmitting module; (8) The signal acquisition module is controlled by the host computer software to collect the signal received by the vector hydrophone, and then the computer terminal processes the collected signal and displays it on the display of the computer terminal; (9) Control the movement of the dual-axis screw slide table through an external control circuit to drive the movement of the vector hydrophone. After the motion of the vector hydrophone stops in the water, repeat the process of steps (5)-(8).