Electromagnetic acoustic-laser non-contact acoustic non-destructive testing system and method

Abstract

The present application discloses an electromagnetic acoustic-laser non-contact acoustic non-destructive testing system and method, which relates to the field of acoustic non-destructive testing technology. The system includes a host computer main control module, a pulse emission module, an electromagnetic acoustic-laser non-contact acoustic sensor and a laser vibration measurement module; the host computer main control module is used to issue instructions to the pulse emission module; the pulse emission module is used to emit pulse signals to the electromagnetic acoustic-laser non-contact acoustic sensor; the electromagnetic acoustic excitation module in the electromagnetic acoustic-laser non-contact acoustic sensor is used to emit electromagnetic acoustic signals to the measuring point on the surface of the object to be inspected, and the laser vibration measurement receiving probe module is used to emit laser signals and receive reflected light signals; the laser vibration measurement module is used to demodulate the reflected light signal to obtain the vibration displacement, velocity and acceleration information at the measuring point on the surface of the object to be inspected. The present application can improve the signal-to-noise ratio of non-contact electromagnetic acoustic signals and avoid the ablation effect on the object to be inspected when the laser ultrasonic technology is used as the excitation source.

Description

Technical Field

[0001] The present application relates to the technical field of acoustic non-destructive testing, and in particular to an electromagnetic acoustic-laser non-contact acoustic non-destructive testing system and method. Background Art

[0002] Acoustic nondestructive testing technology has a wide range of applications and has the advantages of wide detection range, large detection depth, fast detection speed, strong penetration ability and accurate defect positioning. At present, although the traditional piezoelectric ultrasonic technology is mature, it is limited by factors such as coupling agent and heat resistance of piezoelectric chips. Its scope of application is limited by temperature. Generally, it can only obtain good detection results below 150°C, and in automatic scanning and inspection, it is often necessary to additionally equip a coupling liquid spraying device, which not only limits its application scenarios, but also makes the system more complicated. Electromagnetic acoustic detection technology and laser ultrasonic technology, as typical non-contact acoustic detection technologies, have been widely used in scientific research and industrial detection. However, pure electromagnetic acoustic or laser ultrasonic excitation and receiving systems still have many disadvantages when performing non-contact detection.

[0003] Due to the low transducer efficiency of electromagnetic acoustic detection technology, the signal-to-noise ratio of the signal obtained by simple electromagnetic ultrasonic transmission and reception is low during non-contact lift-off detection, and the coil of the electromagnetic acoustic sensor usually needs to be closely attached to the surface of the object to be inspected in order to receive a good signal, resulting in a limited lift-off distance of the electromagnetic acoustic receiving sensor. Since the signal received by electromagnetic ultrasound is the current signal induced in the receiving coil by the surface vibration, the acquired amount is indirect, and it is impossible to directly obtain intrinsic information such as vibration displacement, velocity, acceleration, etc. The amount of information obtained is limited by the form of the coil, making it difficult to use for multi-modal detection, and it is impossible to truly realize non-contact acoustic non-destructive testing.

[0004] Laser ultrasound generates sound waves through the thermoelastic mechanism of power lasers, and measures the micro-vibration of sound waves through laser interferometry. During the excitation process, the energy of the pulsed laser is emitted to the surface of the object being inspected, and most of the energy is absorbed by the surface of the object being inspected. Long-term laser ultrasonic testing is likely to cause ablation damage to the surface of the object being inspected. Summary of the invention

[0005] The purpose of this application is to provide an electromagnetic acoustic-laser non-contact acoustic non-destructive testing system and method, which can truly realize non-contact acoustic non-destructive testing, improve the signal-to-noise ratio of non-contact electromagnetic acoustic signals, and avoid the ablation effect of the laser ultrasonic technology on the object being tested when it is used as an excitation source.

[0006] To achieve the above objectives, this application provides the following solutions.

[0007] In a first aspect, the present application provides an electromagnetic acoustic-laser non-contact acoustic non-destructive testing system, which includes a host computer main control module, a pulse emission module, an electromagnetic acoustic-laser non-contact acoustic sensor and a laser vibration measurement module.

[0008] The output end of the host computer main control module is connected to the input end of the pulse emission module, the output end of the pulse emission module is connected to the input end of the electromagnetic sound-laser non-contact acoustic sensor, the output end of the electromagnetic sound-laser non-contact acoustic sensor is connected to the input end of the laser vibration measurement module, and the output end of the laser vibration measurement module is connected to the input end of the host computer main control module.

[0009] The host computer main control module is used to send instructions to the pulse transmitting module, and the instructions are instructions for controlling the pulse transmitting module to transmit pulse signals.

[0010] The pulse transmitting module is used to transmit the pulse signal to the electromagnetic acoustic-laser non-contact acoustic sensor after receiving the instruction sent by the host computer main control module.

[0011] The electromagnetic acoustic-laser non-contact acoustic sensor is arranged just above the surface of the object to be inspected, and comprises an electromagnetic acoustic excitation module and a laser vibration measurement receiving probe module; wherein, the input end of the electromagnetic acoustic excitation module is connected to the output end of the pulse emission module, and the output end of the laser vibration measurement receiving probe module is connected to the input end of the laser vibration measurement module; the electromagnetic acoustic excitation module is used to transmit an electromagnetic acoustic signal to a measuring point on the surface of the object to be inspected after receiving the pulse signal emitted by the pulse emission module, and the laser vibration measurement receiving probe module is used to transmit a laser signal to the measuring point on the surface of the object to be inspected, and receive a reflected light signal generated at the measuring point on the surface of the object to be inspected under the laser signal, and send the reflected light signal to the laser vibration measurement module.

[0012] The laser vibration measurement module is used to demodulate the reflected light signal to obtain vibration displacement, velocity and acceleration information at the measuring point on the surface of the object to be inspected, and send the vibration displacement, velocity and acceleration information to the host computer main control module.

[0013] Optionally, the electromagnetic acoustic excitation module includes a magnet and a coil, wherein the magnet is disposed directly above the coil, and the magnet and the coil are used to generate the electromagnetic acoustic signal and transmit the electromagnetic acoustic signal to a measuring point on the surface of the object under inspection.

[0014] Optionally, the magnet is an annular cylindrical magnet, the coil is a spiral coil, and the annular cylindrical magnet is arranged directly above the spiral coil.

[0015] Optionally, the magnets are two square magnets, the coil is a runway coil, the two square magnets are arranged in parallel and are both disposed directly above the runway coil, and the magnetic poles of the two square magnets are in opposite directions.

[0016] Optionally, the magnets are two annular cylindrical magnets, the coil is a spiral coil, the two annular cylindrical magnets are coaxially mounted and are both arranged directly above the spiral coil, and the magnetic poles of the two annular cylindrical magnets are in opposite directions.

[0017] Optionally, the laser vibrometer receiving probe module includes a laser vibrometer receiving probe, which is perpendicular to the surface of the object to be inspected, and is used to transmit the laser signal to the surface of the object to be inspected along a direction perpendicular to the surface of the object to be inspected, and receive the reflected light signal in the direction perpendicular to the surface of the object to be inspected.

[0018] Optionally, the laser vibrometer receiving probe module includes two laser vibrometer receiving probes.

[0019] One of the laser vibration measurement receiving probes is perpendicular to the surface of the object to be inspected, and is used to transmit the laser signal to the surface of the object to be inspected along the direction perpendicular to the surface of the object to be inspected, and receive the reflected light signal in the direction perpendicular to the surface of the object to be inspected.

[0020] An angle is set between the other laser vibration measurement receiving probe and the surface of the object to be inspected, so as to transmit the laser signal to the surface of the object to be inspected along the inclined direction of the surface of the object to be inspected, and receive the reflected light signal in the inclined direction of the surface of the object to be inspected.

[0021] Optionally, the laser vibrometer receiving probe module includes three laser vibrometer receiving probes.

[0022] One of the laser vibration measurement receiving probes is perpendicular to the surface of the object to be inspected, and is used to transmit the laser signal to the surface of the object to be inspected along the direction perpendicular to the surface of the object to be inspected, and receive the reflected light signal in the direction perpendicular to the surface of the object to be inspected.

[0023] The other two laser vibration measurement receiving probes are respectively provided with an angle with the surface of the inspected object, and are respectively used to transmit the laser signal to the surface of the inspected object along the inclined direction of the surface of the inspected object, and receive the reflected light signal in the inclined direction of the surface of the inspected object.

[0024] Optionally, the host computer main control module has built-in pulse emission control software and laser vibration measurement control software.

[0025] The pulse emission control software is used to set the waveform, frequency and amplitude of the pulse signal output by the pulse emission module.

[0026] The laser vibrometer control software is used to control the power and emission direction of the laser vibrometer receiving probe module when emitting the laser signal, and to demodulate and display the reflected light signal and the vibration displacement, velocity and acceleration information.

[0027] In a second aspect, the present application proposes an electromagnetic acoustic-laser non-contact acoustic non-destructive testing method, which includes the following steps.

[0028] The host computer main control module is used to send instructions to the pulse transmitting module, wherein the instructions are instructions for controlling the pulse transmitting module to transmit pulse signals.

[0029] According to the instruction, the pulse signal is transmitted to the electromagnetic acoustic-laser non-contact acoustic sensor by using a pulse transmitting module.

[0030] The electromagnetic acoustic excitation module in the electromagnetic acoustic-laser non-contact acoustic sensor is used to transmit electromagnetic acoustic signals to the measuring points on the surface of the object to be inspected, and the laser vibration receiving probe module is used to transmit laser signals to the measuring points on the surface of the object to be inspected and receive reflected light signals.

[0031] The reflected light signal is demodulated by a laser vibration measurement module to obtain vibration displacement, velocity and acceleration information at a measurement point on the surface of the object under inspection.

[0032] According to the specific embodiments provided in this application, this application discloses the following technical effects.

[0033] The present application provides an electromagnetic acoustic-laser non-contact acoustic non-destructive testing system and method. The electromagnetic acoustic-laser non-contact acoustic non-destructive testing system includes a host computer main control module, a pulse emission module, an electromagnetic acoustic-laser non-contact acoustic sensor and a laser vibration measurement module. The electromagnetic acoustic-laser non-contact acoustic sensor is used to combine the electromagnetic acoustic detection technology and the laser vibration measurement technology to perform non-contact acoustic non-destructive testing. The electromagnetic acoustic-laser non-contact acoustic sensor is set on the surface of the object to be inspected. Under the excitation of the pulse signal of the pulse emission module, the electromagnetic acoustic excitation of the electromagnetic acoustic-laser non-contact acoustic sensor is The module transmits an electromagnetic acoustic signal to the measuring point on the surface of the object to be inspected, and the laser vibration measurement receiving probe module transmits a laser signal to the measuring point on the surface of the object to be inspected and receives the reflected light signal, so that by demodulating the reflected light signal, the vibration displacement, velocity, acceleration and other information at the measuring point on the surface of the object to be inspected can be detected, thereby realizing true non-contact acoustic non-destructive testing based on electromagnetic acoustic detection technology and laser vibration measurement technology, effectively improving the signal-to-noise ratio of non-contact electromagnetic acoustic signals, and avoiding the ablation effect of the object to be inspected when the laser ultrasonic technology is used as the excitation source, ensuring that the object to be inspected is not damaged during the detection process. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0035] Figure 1 A schematic diagram of the structure of an electromagnetic acoustic-laser non-contact acoustic non-destructive testing system provided in one embodiment of the present application.

[0036] Figure 2 A cross-sectional view of the internal structure of a one-dimensional vibrometry-type electromagnetic acoustic-laser non-contact acoustic sensor provided in one embodiment of the present application.

[0037] Figure 3 A cross-sectional view of the internal structure of a three-dimensional vibrometry-type electromagnetic acoustic-laser non-contact acoustic sensor provided in one embodiment of the present application.

[0038] Figure 4 This is a schematic diagram of the connection between the laser vibrometer receiving probe module and the laser vibrometer module in the three-dimensional vibrometer-type electromagnetic acoustic-laser non-contact acoustic sensor provided in one embodiment of the present application.

[0039] Figure 5 A schematic structural diagram of a nondestructive testing system based on a split electromagnetic acoustic-laser non-contact acoustic sensor provided in one embodiment of the present application.

[0040] Figure 6 A cross-sectional view of the internal structure of an electromagnetic acoustic excitation sensor 1A provided in one embodiment of the present application.

[0041] Figure 7 A cross-sectional view of the internal structure of a laser vibrometer receiving sensor 1B provided in one embodiment of the present application.

[0042] Figure 8 A schematic diagram of the principle of decomposing the vibration components of a laser vibrometer receiving probe module in a three-dimensional vibrometer-type electromagnetic acoustic-laser non-contact acoustic sensor provided in one embodiment of the present application.

[0043] Fig. 9 A schematic flow chart of an electromagnetic acoustic-laser non-contact acoustic non-destructive testing method provided in one embodiment of the present application.

[0044] Reference numerals:

[0045] 1-electromagnetic acoustic-laser non-contact acoustic sensor; 2-pulse emission module; 3-laser vibration measurement module; 4-upper computer main control module; 11-annular cylindrical magnet; 12-spiral coil; 13-laser vibration measurement receiving probe; 14-housing; 31-first laser vibration measurement unit; 32-second laser vibration measurement unit; 33-third laser vibration measurement unit; 131-first laser vibration measurement receiving probe; 132-second laser vibration measurement receiving probe; 133-third laser vibration measurement receiving probe. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0047] In order to make the purpose, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0048] like Figure 1 As shown, this embodiment proposes an electromagnetic acoustic-laser non-contact acoustic non-destructive testing system, which includes an electromagnetic acoustic-laser non-contact acoustic sensor 1, a pulse emission module 2, a laser vibration measurement module 3 and a host computer main control module 4.

[0049] Among them, the output end of the host computer main control module 4 is connected to the input end of the pulse emission module 2, the output end of the pulse emission module 2 is connected to the input end of the electromagnetic sound-laser non-contact acoustic sensor 1, the output end of the electromagnetic sound-laser non-contact acoustic sensor 1 is connected to the input end of the laser vibration measurement module 3, and the output end of the laser vibration measurement module 3 is connected to the input end of the host computer main control module 4.

[0050] In this embodiment, the host computer main control module 4 is used to send instructions to the pulse emission module 2, and the instructions are instructions for controlling the pulse emission module 2 to emit pulse signals. The host computer main control module 4 is also used to set parameters of the output signal of the pulse emission module 2 and control the emission of pulse signals, as well as the emission of the laser of the laser vibration measurement module 3 and the display, collection and processing of the reflected light signal.

[0051] In this embodiment, the pulse transmitting module 2 is used to transmit a pulse signal to the electromagnetic acoustic-laser non-contact acoustic sensor 1 after receiving an instruction sent by the host computer main control module 4 .

[0052] In this embodiment, the electromagnetic acoustic-laser non-contact acoustic sensor 1 is arranged just above the surface of the object to be inspected, and does not contact the object to be inspected. After receiving the pulse signal emitted by the pulse emission module 2, the electromagnetic acoustic excitation module in the electromagnetic acoustic-laser non-contact acoustic sensor 1 emits an electromagnetic acoustic signal to the measuring point on the surface of the object to be inspected; then the laser vibration measurement receiving probe module in the electromagnetic acoustic-laser non-contact acoustic sensor 1 emits a laser signal to the measuring point on the surface of the object to be inspected and receives the reflected light signal at the measuring point on the surface of the object to be inspected, and sends the reflected light signal to the laser vibration measurement module 3. Among them, the electromagnetic acoustic excitation module is only responsible for excitation, and the laser vibration measurement receiving probe module is only responsible for receiving. Although the laser vibration measurement receiving probe module can emit a laser signal, the laser signal will not generate a laser ultrasonic signal, but is only for receiving the reflected light signal reflected from the surface of the object to be inspected. The electromagnetic acoustic signal is an excitation sound wave signal, which acts on the measuring point on the surface of the object to be inspected. It is combined with the laser vibration measurement receiving probe module to transmit the laser signal and receive the reflected light signal, so that the reflected light signal contains the detection information under the excitation of the electromagnetic acoustic signal, which helps to obtain more accurate and reliable vibration displacement, velocity, acceleration and other information.

[0053] In this embodiment, the laser vibration measurement module 3 is used to demodulate the reflected light signal. When demodulating the reflected light signal, the emitted laser signal is combined and the interference method is adopted to demodulate the vibration displacement, velocity, acceleration and other information at the measuring point on the surface of the object under inspection. The vibration displacement, velocity, acceleration and other information are sent to the host computer main control module 4, which displays and performs subsequent processing.

[0054] In this embodiment, the vibration displacement, velocity, acceleration and other information of the measuring point can be used as the detection result, and the sound field signals in different directions of the measuring point can be further analyzed, and the source of each wave packet in the displacement signal can be determined according to the propagation path of the sound wave in the object under test, and the thickness of the object under test and the location and size of the internal defects can be calculated through the moment of boundary reflection wave packets and defect wave packets, and the thickness of the object under test and the location and size of the internal defects can also be further used as the detection result. Among them, the wave packet refers to a localized wave formed by the superposition of several harmonics.

[0055] In this embodiment, the electromagnetic acoustic-laser non-contact acoustic sensor 1 includes an electromagnetic acoustic excitation module, a laser vibration receiving probe module and a housing 14. Among them, the input end of the electromagnetic acoustic excitation module is connected to the output end of the pulse transmitting module 2. The pulse signal output by the pulse transmitting module 2 is transmitted to the electromagnetic acoustic excitation module, and the frequency and amplitude of the output pulse signal meet the requirements of the electromagnetic acoustic excitation module to excite sound waves in the metal material. After receiving the pulse signal emitted by the pulse transmitting module 2, the electromagnetic acoustic excitation module emits an electromagnetic acoustic signal to the measuring point on the surface of the object to be inspected. The output end of the laser vibration receiving probe module is connected to the input end of the laser vibration measuring module 3. The laser vibration receiving probe module is used to emit a laser signal to the measuring point on the surface of the object to be inspected after receiving the pulse signal emitted by the pulse transmitting module 2, and receive the reflected light signal generated at the measuring point on the surface of the object to be inspected under the laser signal, and send the reflected light signal to the laser vibration measuring module 3. The laser vibration measurement module 3 is used to cooperate with the laser vibration measurement receiving probe module to transmit laser signals, and obtain the particle vibration signal at the measuring point on the surface of the object under test by demodulating and analyzing the intensity change and phase change of the reflected light signal, thereby obtaining information such as vibration displacement, velocity and acceleration. The housing 14 is used to fix the magnet, coil, laser vibration measurement receiving probe 13, wires and optical cables, etc.

[0056] This embodiment combines the electromagnetic acoustic detection technology and the laser vibrometer technology to form an electromagnetic acoustic-laser non-contact acoustic sensor 1, which uses the electromagnetic acoustic method as a method for generating sound waves to avoid the damage to the material surface caused by the ablation mechanism during the laser ultrasonic excitation process, and uses the laser vibrometer method as a method for receiving sound waves to avoid the shortcomings of small lift-off, limited mode, and non-intrinsic vibration measurement in electromagnetic ultrasonic reception.

[0057] In this embodiment, the electromagnetic acoustic-laser non-contact acoustic sensor 1 may be an integrated sensor or a split sensor formed by an electromagnetic acoustic excitation module and a laser vibration measurement receiving probe module.

[0058] In this embodiment, the electromagnetic acoustic excitation module includes a magnet and a coil, and the magnet is arranged directly above the coil. The magnet and the coil are used to excite the electromagnetic acoustic signal and transmit the electromagnetic acoustic signal to the measuring point on the surface of the object to be inspected. Among them, the magnet can be a permanent magnet or an electromagnet. When the electromagnetic acoustic-laser non-contact acoustic sensor 1 is an integrated sensor formed by the electromagnetic acoustic excitation module and the laser vibration receiving probe module, one or more holes are arranged on the magnet, and the holes are used to place the laser vibration receiving probe 13 in the laser vibration receiving probe module. The coil can be a hand-wound coil or a PCB (Printed Circuit Board) coil. According to the type of acoustic wave excited, the coil can be in the shape of a ring, a runway, a folded shape, a wiring shape or a butterfly shape.

[0059] In this embodiment, the magnet may be an annular cylindrical magnet 11, and the coil may be a spiral coil 12. The annular cylindrical magnet 11 is arranged directly above the spiral coil 12. The cooperation of the annular cylindrical magnet 11 and the spiral coil 12 can excite acoustic wave signals such as ultrasonic shear waves.

[0060] In this embodiment, the magnets may be two square magnets, and the coil may be a runway coil. The two square magnets are arranged side by side and are both located directly above the runway coil. The magnetic poles of the two square magnets are in opposite directions. The cooperation of the two square magnets and the runway coil can excite acoustic wave signals such as ultrasonic shear waves.

[0061] In this embodiment, the magnet can be two annular cylindrical magnets 11, and the coil can be a spiral coil 12. The two annular cylindrical magnets 11 are coaxially installed and are both arranged directly above the spiral coil 12. The magnetic poles of the two annular cylindrical magnets 11 are in opposite directions. Through the cooperation of the two annular cylindrical magnets 11 and the spiral coil 12, sound wave signals such as ultrasonic longitudinal waves can be excited.

[0062] In this embodiment, the laser vibrometer receiving probe module may include a laser vibrometer receiving probe 13. The laser vibrometer receiving probe 13 (i.e., the first laser vibrometer receiving probe 131) is perpendicular to the surface of the object to be inspected, and is used to transmit a laser signal to the surface of the object to be inspected along a direction perpendicular to the surface of the object to be inspected, and receive a reflected light signal reflected from the surface of the object to be inspected.

[0063] In this embodiment, the laser vibrometer receiving probe module may also include two laser vibrometer receiving probes 13. One of the laser vibrometer receiving probes 13 (i.e., the first laser vibrometer receiving probe 131) is perpendicular to the surface of the object to be inspected, and is used to transmit a laser signal to the surface of the object to be inspected along the vertical direction of the surface of the object to be inspected, and receive a reflected light signal in the vertical direction of the surface of the object to be inspected; the other laser vibrometer receiving probe 13 (i.e., the second laser vibrometer receiving probe 132 or the third laser vibrometer receiving probe 133) is provided with an angle with the surface of the object to be inspected, and is used to transmit a laser signal to the surface of the object to be inspected along the inclined direction of the surface of the object to be inspected, and receive a reflected light signal in the inclined direction of the surface of the object to be inspected.

[0064] In this embodiment, the laser vibrometer receiving probe module may further include three laser vibrometer receiving probes 13. One of the laser vibrometer receiving probes 13 (i.e., the first laser vibrometer receiving probe 131) is perpendicular to the surface of the object to be inspected, and is used to transmit a laser signal to the surface of the object to be inspected along a direction perpendicular to the surface of the object to be inspected, and receive a reflected light signal from the surface of the object to be inspected. The other two laser vibrometer receiving probes 13 (i.e., the second laser vibrometer receiving probe 132 and the third laser vibrometer receiving probe 133) are respectively provided with an angle with the surface of the object to be inspected, and are respectively used to transmit a laser signal to the surface of the object to be inspected along an inclined direction of the surface of the object to be inspected, and receive a reflected light signal from the surface of the object to be inspected, so as to realize three-dimensional vibration information collection.

[0065] In this embodiment, the host computer main control module 4 is built with pulse emission control software and laser vibration control software. Among them, the pulse emission control software is used to set the waveform, frequency, amplitude and other parameters of the pulse signal output by the pulse emission module 2. The laser vibration control software is used to control the laser vibration receiving probe module to emit laser signals and collect and demodulate reflected light signals, as well as display and post-process the reflected light signals and information results such as vibration displacement, velocity and acceleration.

[0066] In this embodiment, the electromagnetic acoustic-laser non-contact acoustic sensor 1 includes an electromagnetic acoustic excitation module and a laser vibrometer receiving probe module. The electromagnetic acoustic excitation module is used to excite electromagnetic acoustic signals, where the electromagnetic acoustic signals refer to sound wave signals. The electromagnetic acoustic excitation module mainly includes a magnet and a coil, and the cooperation of the magnet and the coil can excite sound waves of different modes, including ultrasonic body waves, ultrasonic guided waves, and surface waves. The laser vibrometer receiving probe module is used for transmitting laser signals and receiving reflected light signals, and may include one to three laser vibrometer receiving probes 13. When three laser vibrometer receiving probes 13 are provided, the three laser vibrometer receiving probes 13 include a first laser vibrometer receiving probe 131, a second laser vibrometer receiving probe 132, and a third laser vibrometer receiving probe 133.

[0067] In this embodiment, when the laser vibrometer receiving probe module includes only one laser vibrometer receiving probe 13, the laser vibrometer receiving probe 13 is perpendicular to the surface of the object to be inspected, and the received displacement signal is the out-of-plane displacement of the measuring point. When the laser vibrometer receiving probe module includes two or three laser vibrometer receiving probes 13, one of the laser vibrometer receiving probes 13 is perpendicular to the surface of the object to be inspected, and the received displacement signal is the out-of-plane displacement of the measuring point. The other laser vibrometer receiving probes 13 form a certain angle with the surface of the object to be inspected, and the received displacement signal is the displacement signal of the measuring point along the direction of the laser vibrometer receiving probe 13. The in-plane displacement of the measuring point can be demodulated by combining the tilt angle and the out-of-plane displacement.

[0068] For example, Figure 2 The one-dimensional vibration measurement type electromagnetic acoustic-laser non-contact acoustic sensor shown in the figure comprises an annular cylindrical magnet 11, a spiral coil 12 and a laser vibration measurement receiving probe 13. The electromagnetic acoustic excitation module comprises an annular cylindrical magnet 11 and a spiral coil 12, which are used to excite ultrasonic shear waves in the object under test. The laser vibration measurement receiving probe module comprises a laser vibration measurement receiving probe 13, which is installed at the center of the annular cylindrical magnet 11 and is used to emit laser signals and receive reflected light signals generated by the off-plane displacement of the measurement point.

[0069] For example, Figure 3 The three-dimensional vibration measurement type electromagnetic acoustic-laser non-contact acoustic sensor shown includes an annular cylindrical magnet 11, a spiral coil 12, and a first laser vibration measurement receiving probe 131, a second laser vibration measurement receiving probe 132, and a third laser vibration measurement receiving probe 133. Among them, two channels are provided on the annular cylindrical magnet 11, and the two channels are inclined channels. The inclined channels are provided to ensure that the laser vibration measurement receiving probe 13 can receive displacements in different directions. Since the electromagnetic acoustic-laser non-contact acoustic sensor 1 is generally perpendicular to the surface of the object to be inspected, if the laser vibration measurement receiving probe 13 is installed horizontally, the laser cannot be emitted to the surface of the object to be inspected, so that the laser vibration measurement receiving probe 13 cannot work.

[0070] In this embodiment, the laser vibration measurement receiving probe module includes three laser vibration measurement receiving probes 13, wherein the first laser vibration measurement receiving probe 131 is installed at the center position of the annular cylindrical magnet 11, and the second laser vibration measurement receiving probe 132 and the third laser vibration measurement receiving probe 133 are installed and fixed through the inclined channel of the annular cylindrical magnet 11, and are used to emit laser signals and receive reflected light signals generated by the displacement of the measuring point.

[0071] In this embodiment, the pulse transmitting module 2 is connected to the coil of the electromagnetic acoustic-laser non-contact acoustic sensor 1 , and is used to output a high-energy pulse electrical signal to the coil of the electromagnetic acoustic-laser non-contact acoustic sensor 1 .

[0072] In this embodiment, the laser vibrometer module 3 is provided with a corresponding number of laser vibrometer units according to the number of laser vibrometer receiving probes 13, which are respectively connected to the laser vibrometer receiving probes 13, and are used for the analysis of the emission of the laser and the reflected light signal of the laser vibrometer receiving probes 13. For example, when three laser vibrometer receiving probes 13 are provided, namely, a first laser vibrometer receiving probe 131, a second laser vibrometer receiving probe 132, and a third laser vibrometer receiving probe 133, three laser vibrometer units are also provided correspondingly, namely, a first laser vibrometer unit 31, a second laser vibrometer unit 32, and a third laser vibrometer unit 33.

[0073] For example, Figure 4 The diagram shows a connection diagram of a laser vibrometer receiving probe module and a laser vibrometer module 3 in a three-dimensional vibrometer-type electromagnetic acoustic-laser non-contact acoustic sensor. The first laser vibrometer receiving probe 131, the second laser vibrometer receiving probe 132 and the third laser vibrometer receiving probe 133 of the three-dimensional vibrometer-type electromagnetic acoustic-laser non-contact acoustic sensor are connected to the first laser vibrometer unit 31, the second laser vibrometer unit 32 and the third laser vibrometer unit 33 of the laser vibrometer module 3, respectively.

[0074] In this embodiment, the host computer main control module 4 is connected to the pulse emission module 2 and the laser vibration measurement module 3, and has built-in pulse emission control software and laser vibration measurement control software. Among them, the pulse emission control software is used to control the waveform, frequency, phase and amplitude of the pulse signal output by the pulse transmitter; the laser vibration measurement control software is used to control the laser emission and reflected light signal analysis and processing of the laser vibration measurement module 3, as well as the display, collection and processing of acoustic signals.

[0075] like Figure 5 As shown, this embodiment also provides a nondestructive testing system of a split electromagnetic acoustic-laser non-contact acoustic sensor, which includes an electromagnetic acoustic excitation sensor 1A, a laser vibration receiving sensor 1B, a pulse transmitting module 2, a laser vibration measuring module 3 and a host computer main control module 4. Among them, the electromagnetic acoustic excitation sensor 1A and the laser vibration receiving sensor 1B constitute a split electromagnetic acoustic-laser non-contact acoustic sensor.

[0076] Figure 6 1A is a cross-sectional view of the internal structure of the electromagnetic acoustic excitation sensor 1A, which is equivalent to an electromagnetic acoustic excitation module and includes a magnet, a coil and a housing 14. The coil is connected to the pulse emission module 2.

[0077] Figure 71 is a cross-sectional view of the internal structure of the laser vibrometer receiving sensor 1B, which is equivalent to a laser vibrometer receiving probe module, and includes a first laser vibrometer receiving probe 131, a second laser vibrometer receiving probe 132, a third laser vibrometer receiving probe 133 and a housing 14. The first laser vibrometer receiving probe 131, the second laser vibrometer receiving probe 132 and the third laser vibrometer receiving probe 133 are connected to the laser vibrometer module 3, respectively.

[0078] Figure 8 The figure is a schematic diagram of the vibration component decomposition of the laser vibrometer receiving probe module in the three-dimensional vibrometer electromagnetic acoustic-laser non-contact acoustic sensor. Figure 8 As shown, CH1, CH2, and CH3 are the arrangement directions of the first laser vibrometer receiving probe 131, the second laser vibrometer receiving probe 132, and the third laser vibrometer receiving probe 133, respectively. V is the vibration (displacement, velocity, acceleration) vector of the measuring point, V 1. V 2. V 3 are vibration information of the measuring point demodulated by the first laser vibrometer receiving probe 131, the second laser vibrometer receiving probe 132 and the third laser vibrometer receiving probe 133, respectively. u x , u y , u z are the vibration components in the three orthogonal directions of X, Y, and Z at the target position, θ for V 2 and V 1, for V 3 and V 1. Among them, the off-plane vibration component u z Equal to the vibration information received by the laser vibration receiving probe 13 in the CH1 direction, the in-plane vibration component u x and u y It can be calculated using formula (1).

[0079] (1).

[0080] in, u x and u y They are the vibration components in the two orthogonal directions of X and Y at the target position; V 1. V 2. V3 are vibration information of the measuring points demodulated by the first laser vibrometer receiving probe 131, the second laser vibrometer receiving probe 132 and the third laser vibrometer receiving probe 133 respectively; θ for V 2 and V 1, for V 3 and V 1.

[0081] In an exemplary embodiment, an electromagnetic acoustic-laser non-contact acoustic non-destructive testing method is also provided, such as Fig. 9 As shown, the electromagnetic acoustic-laser non-contact acoustic non-destructive testing method mainly includes the following steps.

[0082] Step S1, using the host computer main control module 4 to send instructions to the pulse transmitting module 2, wherein the instructions are instructions for controlling the pulse transmitting module 2 to transmit a pulse signal.

[0083] Step S2: according to the instruction, using the pulse transmitting module 2 to transmit the pulse signal to the electromagnetic acoustic-laser non-contact acoustic sensor 1.

[0084] Step S3, using the electromagnetic acoustic excitation module in the electromagnetic acoustic-laser non-contact acoustic sensor 1 to transmit electromagnetic acoustic signals to the measuring points on the surface of the object to be inspected, and using the laser vibration measurement receiving probe module to transmit laser signals to the measuring points on the surface of the object to be inspected and receive reflected light signals.

[0085] Step S4: Demodulate the vibration signal and the reflected light signal using the laser vibration measurement module 3 to obtain information such as vibration displacement, velocity, acceleration, etc. at the measuring point on the surface of the object under inspection.

[0086] The following electromagnetic acoustic-laser non-contact acoustic sensor uses a three-dimensional vibration measurement type electromagnetic acoustic-laser non-contact acoustic sensor as an example to further illustrate the actual implementation operation process of acoustic non-destructive testing when the electromagnetic acoustic-laser non-contact acoustic non-destructive testing system in this embodiment is actually used.

[0087] (1) After installing and fixing the electromagnetic acoustic-laser non-contact acoustic sensor 1 above the detection area of ​​the object to be inspected, the pulse emission module 2, the laser vibration measurement module 3 and the host computer main control module 4 are connected in sequence.

[0088] (2) Edit the transmission waveform in the pulse transmission control software of the host computer main control module 4 and set the waveform, frequency, phase, amplitude and other parameters of the output pulse signal.

[0089] (3) The electromagnetic acoustic excitation module of the electromagnetic acoustic-laser non-contact acoustic sensor 1 excites ultrasonic longitudinal waves in the object to be inspected. At the same time, the laser emission switch of the laser vibrometer module 3 is turned on in the laser vibrometer control software.

[0090] (4) The first laser vibrometer receiving probe 131, the second laser vibrometer receiving probe 132 and the third laser vibrometer receiving probe 133 of the electromagnetic acoustic-laser non-contact acoustic sensor 1 respectively emit laser signals and receive reflected light signals of the particles vibrating in different directions under the control of the laser vibrometer module 3. The analysis of the received reflected light signals is controlled in real time in the laser vibrometer control software to display, collect and process the vibration signals of the three particles in different directions.

[0091] (5) Analyze the displacement signals in different directions of the measuring point, determine the source of each wave packet in the displacement signal according to the propagation path of the sound wave in the object under test, and calculate the thickness of the object under test and the location and size of the internal defects through the timing of the boundary reflection wave packet and the defect wave packet.

[0092] The electromagnetic acoustic-laser non-contact acoustic non-destructive testing system of this embodiment includes an electromagnetic acoustic-laser non-contact acoustic sensor 1, a pulse emission module 2, a laser vibration measurement module 3 and a host computer main control module 4. Among them, the electromagnetic acoustic-laser non-contact acoustic sensor 1 includes an electromagnetic acoustic excitation module and a laser vibration measurement receiving probe module. In work, based on the electromagnetic acoustic transduction mechanism, sound waves (ultrasonic body waves, ultrasonic guided waves and surface waves, etc.) are excited in the metal material, and then the laser vibration measurement mechanism is used to receive the sound wave signal. In this embodiment, laser ultrasound is used to replace electromagnetic sound as a receiving means. Thanks to the high precision and high resolution of laser ultrasonic technology displacement detection, it can accurately measure the displacement, velocity, acceleration and other information of the particle vibrating in a single direction, and overcome the problems of low transduction efficiency, weak signal-to-noise ratio and non-original real vibration of the electromagnetic ultrasonic sensor as a receiver. At the same time, by using electromagnetic acoustic emission with lower energy efficiency to replace laser ultrasonic emission, the ablation effect of laser ultrasonic technology on the object under inspection is avoided when it is used as an excitation source. The electromagnetic acoustic excitation sensor has the characteristics of single mode and strong designability, which can effectively solve the problem of difficult laser ultrasonic mode control. The electromagnetic acoustic-laser non-contact acoustic non-destructive testing system has the outstanding advantages of allowing a large lift-off height, completely non-contact, no coupling agent, high detection signal-to-noise ratio, and good repeatability. It is very suitable for extreme temperature sound wave transmission and reception, automatic scanning imaging flaw detection, acoustic stress measurement and other scenarios.

[0093] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0094] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. An electromagnetic acoustic-laser non-contact acoustic non-destructive testing system, characterized in that: The electromagnetic acoustic-laser non-contact acoustic non-destructive testing system comprises a host computer main control module, a pulse emission module, an electromagnetic acoustic-laser non-contact acoustic sensor and a laser vibration measurement module; The output end of the host computer main control module is connected to the input end of the pulse transmission module, the output end of the pulse transmission module is connected to the input end of the electromagnetic sound-laser non-contact acoustic sensor, the output end of the electromagnetic sound-laser non-contact acoustic sensor is connected to the input end of the laser vibration measurement module, and the output end of the laser vibration measurement module is connected to the input end of the host computer main control module; The host computer main control module is used to send instructions to the pulse transmitting module, and the instructions are instructions for controlling the pulse transmitting module to transmit a pulse signal; The pulse transmitting module is used to transmit the pulse signal to the electromagnetic acoustic-laser non-contact acoustic sensor after receiving the instruction issued by the host computer main control module; The electromagnetic acoustic-laser non-contact acoustic sensor is arranged just above the surface of the object to be inspected, and comprises an electromagnetic acoustic excitation module and a laser vibration measurement receiving probe module; wherein the input end of the electromagnetic acoustic excitation module is connected to the output end of the pulse emission module, and the output end of the laser vibration measurement receiving probe module is connected to the input end of the laser vibration measurement module; the electromagnetic acoustic excitation module is used to transmit an electromagnetic acoustic signal to a measuring point on the surface of the object to be inspected after receiving the pulse signal emitted by the pulse emission module, and the laser vibration measurement receiving probe module is used to transmit a laser signal to a measuring point on the surface of the object to be inspected, and receive a reflected light signal generated at the measuring point on the surface of the object to be inspected under the laser signal, and send the reflected light signal to the laser vibration measurement module; The laser vibration measurement module is used to demodulate the reflected light signal to obtain vibration displacement, velocity and acceleration information at the measuring point on the surface of the object to be inspected, and send the vibration displacement, velocity and acceleration information to the host computer main control module.

2. The electromagnetic acoustic-laser non-contact acoustic non-destructive testing system according to claim 1, characterized in that: The electromagnetic acoustic excitation module includes a magnet and a coil. The magnet is arranged directly above the coil. The magnet and the coil are used to generate the electromagnetic acoustic signal and transmit the electromagnetic acoustic signal to a measuring point on the surface of the object to be inspected.

3. The electromagnetic acoustic-laser non-contact acoustic non-destructive testing system according to claim 2, characterized in that: The magnet is an annular cylindrical magnet, the coil is a spiral coil, and the annular cylindrical magnet is arranged directly above the spiral coil.

4. The electromagnetic acoustic-laser non-contact acoustic non-destructive testing system according to claim 2, characterized in that: The magnets are two square magnets, the coil is a runway coil, the two square magnets are arranged in parallel and are both arranged directly above the runway coil, and the magnetic poles of the two square magnets are in opposite directions.

5. The electromagnetic acoustic-laser non-contact acoustic non-destructive testing system according to claim 2, characterized in that: The magnets are two annular cylindrical magnets, the coil is a spiral coil, the two annular cylindrical magnets are coaxially installed and are both arranged directly above the spiral coil, and the magnetic poles of the two annular cylindrical magnets are in opposite directions.

6. The electromagnetic acoustic-laser non-contact acoustic non-destructive testing system according to claim 1, characterized in that: The laser vibration measurement receiving probe module includes a laser vibration measurement receiving probe, which is perpendicular to the surface of the object to be inspected. The laser vibration measurement receiving probe is used to transmit the laser signal to the surface of the object to be inspected along the vertical direction of the surface of the object to be inspected, and receive the reflected light signal in the vertical direction of the surface of the object to be inspected.

7. The electromagnetic acoustic-laser non-contact acoustic non-destructive testing system according to claim 1, characterized in that: The laser vibration measurement receiving probe module includes two laser vibration measurement receiving probes; One of the laser vibration measurement receiving probes is perpendicular to the surface of the object to be inspected, and is used to transmit the laser signal to the surface of the object to be inspected along the vertical direction of the surface of the object to be inspected, and receive the reflected light signal in the vertical direction of the surface of the object to be inspected; An angle is set between the other laser vibration measurement receiving probe and the surface of the object to be inspected, so as to transmit the laser signal to the surface of the object to be inspected along the inclined direction of the surface of the object to be inspected, and receive the reflected light signal in the inclined direction of the surface of the object to be inspected.

8. The electromagnetic acoustic-laser non-contact acoustic non-destructive testing system according to claim 1, characterized in that: The laser vibration measurement receiving probe module includes three laser vibration measurement receiving probes; One of the laser vibration measurement receiving probes is perpendicular to the surface of the object to be inspected, and is used to transmit the laser signal to the surface of the object to be inspected along the vertical direction of the surface of the object to be inspected, and receive the reflected light signal in the vertical direction of the surface of the object to be inspected; The other two laser vibration measurement receiving probes are respectively provided with an angle with the surface of the inspected object, and are respectively used to transmit the laser signal to the surface of the inspected object along the inclined direction of the surface of the inspected object, and receive the reflected light signal in the inclined direction of the surface of the inspected object.

9. The electromagnetic acoustic-laser non-contact acoustic non-destructive testing system according to claim 1, characterized in that: The host computer main control module is equipped with pulse emission control software and laser vibration measurement control software; The pulse emission control software is used to set the waveform, frequency and amplitude of the pulse signal output by the pulse emission module; The laser vibrometer control software is used to control the power and emission direction of the laser vibrometer receiving probe module when emitting the laser signal, and to demodulate and display the reflected light signal and the vibration displacement, velocity and acceleration information.

10. An electromagnetic acoustic-laser non-contact acoustic non-destructive testing method based on the electromagnetic acoustic-laser non-contact acoustic non-destructive testing system according to claim 1, characterized in that: The electromagnetic acoustic-laser non-contact acoustic non-destructive testing method comprises: Using the host computer main control module to send instructions to the pulse transmitting module, the instructions are instructions for controlling the pulse transmitting module to transmit a pulse signal; According to the instruction, the pulse signal is transmitted to the electromagnetic acoustic-laser non-contact acoustic sensor by using the pulse transmitting module; The electromagnetic acoustic excitation module in the electromagnetic acoustic-laser non-contact acoustic sensor is used to emit an electromagnetic acoustic signal to a measuring point on the surface of the object to be inspected, and the laser vibration receiving probe module is used to emit a laser signal to the measuring point on the surface of the object to be inspected and receive a reflected light signal; The reflected light signal is demodulated by a laser vibration measurement module to obtain vibration displacement, velocity and acceleration information at a measurement point on the surface of the object under inspection.

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