CN115184462A - Laser ultrasonic detection system based on combined non-contact probe - Google Patents
Laser ultrasonic detection system based on combined non-contact probe Download PDFInfo
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- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/04—Analysing solids
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- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/1702—Systems in which incident light is modified in accordance with the properties of the material investigated with opto-acoustic detection, e.g. for gases or analysing solids
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- G01N29/2418—Probes using optoacoustic interaction with the material, e.g. laser radiation, photoacoustics
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- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/1702—Systems in which incident light is modified in accordance with the properties of the material investigated with opto-acoustic detection, e.g. for gases or analysing solids
- G01N2021/1706—Systems in which incident light is modified in accordance with the properties of the material investigated with opto-acoustic detection, e.g. for gases or analysing solids in solids
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Abstract
The invention relates to the technical field of nondestructive testing, in particular to a laser ultrasonic testing system based on a combined non-contact probe, which comprises: the device comprises a laser, a laser scanning module, a combined non-contact probe and a computer. The laser beam emitted by the laser generates a laser ultrasonic signal on an object to be detected through the laser scanning module, the laser ultrasonic signal is received by the combined non-contact probe, finally, the defect analysis of the signal is carried out on the computer, the array sequence between the microphones and the air coupling probes which are different from each other in distance with the rotation center is adjusted through the rotation of the substrate in the combined non-contact probe, so that the combined non-contact probe is adapted to the object to be detected under different thickness distribution conditions, the efficiency of laser ultrasonic detection is improved, and the receiving accuracy of the laser ultrasonic signal is increased.
Description
Technical Field
The invention relates to the technical field of nondestructive testing, in particular to a laser ultrasonic testing system based on a combined non-contact probe.
Background
Laser ultrasound is a novel nondestructive testing technology emerging in recent ten years, and has the advantages of high resolution, non-contact, long testing distance and the like. The receiving method of the laser ultrasonic signal mainly comprises an optical method and an electrical method, wherein the optical method mainly uses an optical interferometer to receive the laser ultrasonic signal, but the optical interferometer is large in size and has high requirements on a detection object and a detection environment; the electrical method mainly uses a piezoelectric transducer to receive ultrasonic signals, but a coupling agent is required in the detection process, and the detection range is small.
The penetrability and the accuracy of laser ultrasound are negatively correlated, when nondestructive detection is carried out, when an object to be detected is uneven or irregular in thickness, thick local signals are easy to attenuate and are difficult to penetrate, incomplete acquisition is caused, or the thin local ultrasonic frequency is low, the acquired information detection resolution is low, and coupling or contact methods adopted by all receiving methods are different, so that the matching use is difficult, and the operation is very troublesome.
Disclosure of Invention
The application provides a laser ultrasonic detection system based on combination formula non-contact probe, has solved among the prior art to the low complicated problem of flow of the inhomogeneous object detection precision of thickness.
The application provides a laser ultrasonic testing system based on combination formula non-contact probe, includes:
the laser is electrically connected with the computer and used for emitting laser beams according to laser parameters set by the computer;
the laser scanning module is arranged between the laser and the object to be detected and is used for controlling the laser beam to scan the object to be detected;
the combined non-contact probe is electrically connected with the computer and is used for receiving the laser ultrasonic signal on the object to be detected and transmitting the laser ultrasonic signal to the computer; the combined non-contact probe includes: the device comprises a microphone, an air coupling probe and at least four substrates which are at the same rotation center, wherein the same substrate is only provided with the microphone or the air coupling probe, and the distances from the microphone or the air coupling probe arranged on different substrates to the rotation center are different; there is at least one microphone on the substrate at a distance from the center of rotation that is greater than the distance from the air-coupled probe on one substrate to the center of rotation and less than the distance from the air-coupled probe on the other substrate to the center of rotation; there is at least one air-coupled probe on the substrate at a distance from the center of rotation that is greater than the distance from the microphone on one substrate to the center of rotation and less than the distance from the microphone on the other substrate to the center of rotation;
and the computer is used for setting laser parameters for the laser and carrying out defect analysis on the laser ultrasonic signals received by the combined non-contact probe.
Optionally, the substrate is an annular substrate, adjacent substrates are mutually matched, and each microphone and the air coupling probe are located on the same plane.
Optionally, the mutual adaptation between the adjacent substrates specifically includes: the outer diameter of one substrate between the adjacent annular substrates is equal to the inner diameter of the other substrate, and a bearing structure is arranged on the contact surface between the substrates.
Optionally, in the combined non-contact probe, a plurality of air coupling probes with different main frequencies are arranged on the same substrate, and distances between the air coupling probes on the same substrate and the rotation center are the same.
Optionally, the receiving main frequency range of the air coupling probe is 100KHz to 2MHz.
Optionally, in the combined non-contact probe, a plurality of microphones with different center frequencies are disposed on the same substrate, and distances between the microphones on the same substrate and the rotation center are the same.
Optionally, the microphones on the same substrate form an annular array around the rotation center, the microphone array is formed by alternately arranging microphones with multiple center frequencies, each kind of center frequency has multiple microphones, and the multiple microphones with the same center frequency are uniformly distributed around the center of the microphone array.
Optionally, the distance between adjacent microphones satisfies the space sampling theorem, which specifically includes:
wherein d is the distance between the microphones, and λ is the wavelength of the sound wave corresponding to the highest central frequency in the microphone array.
Optionally, the laser ultrasonic detection system based on the combined non-contact probe further includes:
and the signal processing module is arranged on an electric connection circuit between the combined non-contact probe and the computer and is used for preprocessing the laser ultrasonic signal received by the combined non-contact probe.
Optionally, the preprocessing of the laser ultrasonic signal by the signal processing module specifically includes: filtering and amplifying.
The application provides a laser ultrasonic testing system based on combination formula non-contact probe, the laser beam that the laser instrument sent, through laser scanning module waiting to detect the object and producing laser ultrasonic signal, receive by combination formula non-contact probe again, carry out the defect analysis of signal at the computer at last, it is rotatory through the base plate among the combination formula non-contact probe, adjust the array order between microphone and the air coupling probe apart from the rotation center diverse, make combination formula non-contact probe adaptation wait to detect the object in the thin and thick distribution condition of difference, the efficiency of laser ultrasonic testing is improved, the receiving precision of laser ultrasonic signal is increased.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without inventive exercise.
Fig. 1 is a first structural schematic diagram of a combined non-contact probe-based laser ultrasonic inspection system provided in the present application;
FIG. 2 is a second schematic diagram of the laser ultrasonic inspection system based on the combined non-contact probe provided in the present application;
fig. 3 is a schematic structural diagram of a signal processing module according to the present application.
Wherein the reference numerals are:
10. a laser; 20. a laser scanning module; 30. a combined non-contact probe; 31. a microphone; 32. an air coupling probe; 33. a substrate; 40. a computer; 50. and a signal processing module.
Detailed Description
In order to make the objects, features and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The application provides a laser ultrasonic detection system based on combination formula non-contact probe, has solved among the prior art and has detected the low complicated problem of flow of low precision to the inhomogeneous object of thickness.
Referring to fig. 1, fig. 1 is a first structural schematic diagram of a laser ultrasonic inspection system based on an assembled non-contact probe according to the present application.
The embodiment provides a laser ultrasonic detection system based on combined non-contact probe, including:
the laser 10 is electrically connected with the computer 40 and is used for emitting laser beams according to laser parameters set by the computer 40;
it should be noted that, the computer 40 sets the laser parameters, controls the wavelength frequency of the laser emitted by the laser 10, and the laser beam is incident on the laser scanning module 20, and the laser 10 and the laser scanning module 20 may not be connected physically.
The laser scanning module 20 is arranged between the laser 10 and the object to be detected and is used for controlling the laser beam to scan the object to be detected;
it should be noted that the laser scanning module 20 receives the laser beam emitted by the laser 10, and controls the laser beam to deflect, so as to perform laser scanning on the object to be detected.
The combined non-contact probe 30 is electrically connected with the computer 40 and is used for receiving the laser ultrasonic signal on the object to be detected and transmitting the laser ultrasonic signal to the computer 40; the combined non-contact probe 30 includes: the device comprises a microphone 31, an air coupling probe 32 and at least four substrates 33 with the same rotation center, wherein only the microphone 31 or the air coupling probe 32 is arranged on the same substrate 33, and the distances from the microphone 31 or the air coupling probe 32 arranged on different substrates 33 to the rotation center are different; there is at least one microphone 31 on one substrate 33 that is at a distance from the center of rotation that is greater than the distance from the air-coupling probe 32 on one substrate 33 to the center of rotation and less than the distance from the air-coupling probe 32 on the other substrate 33 to the center of rotation; there is at least one air coupling probe on the substrate 33 at a distance from the center of rotation that is greater than the distance from the microphone 31 on one substrate 33 to the center of rotation and less than the distance from the microphone 31 on the other substrate 33 to the center of rotation.
It should be noted that, because the microphones 31 and the air coupling probes 32 are alternately mounted on the adjacent substrates 33, only one of the microphones 31 or the air coupling probes 32 is mounted on one substrate 33; the distance between the non-contact probes arranged on different substrates 33 and the rotation center is different, so that the probes do not obstruct detection when each substrate rotates to any position, and the microphones 31 and the air coupling probes 32 have different arrangement orders through the rotation of the substrates.
The microphone is an acoustic microphone, and based on the lower ultrasonic detection frequency of the microphone 31, the attenuation of the received ultrasonic waves is slow, the penetrating power is strong, but the longitudinal resolution is low; the air coupling probe 32 has high ultrasonic detection frequency, received ultrasonic waves are quickly attenuated, the penetrating power is weak, but the longitudinal resolution is high, the microphone 31 and the air coupling probe 32 are respectively suitable for receiving ultrasonic waves excited on a thicker object and a thinner object, the arrangement sequence of the microphone 31 and the air coupling probe 32 is changed through the rotation of each substrate on the combined non-contact probe 30, the detection can be respectively carried out corresponding to the objects with uneven thickness, such as thin-thick-thin-thick, thin-thick-thin and thick-thin-thick, the time and the workload of workers for replacing the probes back and forth are saved, the detection efficiency and the detection accuracy are improved, and the microphone 31 and the air coupling probe 32 are non-contact probes and can be well matched for working.
And the computer 40 is used for setting laser parameters for the laser 10 and carrying out defect analysis on the laser ultrasonic signals received by the combined non-contact probe 30.
In the computer 40, the laser 10 is controlled to emit a laser beam required for detection by setting laser parameters; and can carry out the three-dimensional formation of image of the object to be detected according to the laser ultrasonic signal, and carry out defect analysis according to the signal.
In this embodiment, a laser beam emitted by the laser 10 generates a laser ultrasonic signal on an object to be detected through the laser scanning module 20, and then the laser ultrasonic signal is received by the combined non-contact probe 30, and finally the signal defect analysis is performed in the computer 40, and the arrangement sequence between the microphones 31 and the air coupling probes 32 with different distances from the rotation center is adjusted through the rotation of the substrate in the combined non-contact probe 30, so that the combined non-contact probe 30 is adapted to the object to be detected with different thickness distribution conditions, the efficiency of laser ultrasonic detection is improved, and the receiving accuracy of the laser ultrasonic signal is improved.
The above is a detailed description of a first embodiment of a combined non-contact probe-based laser ultrasonic inspection system provided by the present application, and the following is a detailed description of a second embodiment of a combined non-contact probe-based laser ultrasonic inspection system provided by the present application.
The microphone in the present embodiment is specifically an acoustic microphone. The ultrasonic signal excited by laser ultrasonic is a wide-band signal, and has no specific range, so that when a detector uses the transducer, in order to ensure the detection resolution, the frequency range of the detected ultrasonic wave is usually 20-100Mhz, other excited low-frequency band ultrasonic signals are ignored, the signal reception of an acoustic microphone with lower receiving frequency cannot be considered, in the initial development stage of the laser ultrasonic detection field, the sensitivity and the response range of the acoustic microphone are not enough to meet the detection requirement, and the detector has an industry bias to the acoustic microphone.
Referring to fig. 2, fig. 2 is a second structural schematic diagram of a laser ultrasonic inspection system based on a combined non-contact probe according to the present application.
The substrates 33 are annular substrates, the adjacent substrates 33 are mutually matched, and the microphones 31 and the air coupling probes 32 are positioned on the same plane.
It should be noted that the plurality of annular substrates 33 are adapted to each other, and may be adjacent substrates without contact, and each substrate has a supporting structure on the back of the non-contact probe installation surface, and is connected to the rotating shaft, so that each annular substrate is looped on one loop on the same plane, and each substrate does not contact with each other.
Further, in this embodiment, the mutual adaptation between the adjacent substrates may further specifically be: the outer diameter of one substrate between the adjacent annular substrates is equal to the inner diameter of the other substrate, and a bearing structure is arranged on a contact surface between the substrates. That is, the substrates are connected to each other by a bearing structure and can rotate around a concentric rotation axis.
In the combined non-contact probe, a plurality of air coupling probes with different main frequencies are arranged on the same substrate, and the distances between the air coupling probes on the same substrate and the rotation center are the same. In the combined non-contact probe, a plurality of microphones with different center frequencies are arranged on the same substrate, and the distances between the microphones on the same substrate and the rotation center are the same.
It should be noted that, only one of the microphones or the air coupling probes is arranged on the same substrate, but a plurality of different frequency types are arranged, so that the arrangement sequence of the microphones and the air coupling probes can be changed, the main frequency or the center frequency of the non-contact probes in the sequence can be adjusted by rotating the substrate, the frequency required for detection is selected, and the application range of the combined non-contact probe is further improved.
Further, the inspector can also arrange the microphones on the same substrate in a circular array around the center of rotation. The microphone array is formed by alternately arranging microphones with various central frequencies, each central frequency is provided with a plurality of microphones, and the plurality of microphones with the same central frequency are uniformly distributed around the center of the microphone array. The detection range is improved by arranging the microphone array, and the microphone array is arranged into an interval annular array meeting the space sampling theorem, so that the microphone array has high detection sensitivity.
The combined non-contact probe may select a desired non-contact probe on different substrates to perform detection, or may simultaneously operate a plurality of microphones in the entire microphone array when the microphone array is provided on the substrate.
For a microphone array, in order to avoid spatial aliasing, a phenomenon occurs that sampled signals are overlapped and distorted when being restored into continuous signals, and the distance between adjacent microphones needs to satisfy the spatial sampling theorem, that is:
wherein d is the distance between the microphones, and λ is the wavelength of the sound wave corresponding to the highest central frequency in the microphone array.
According to the characteristics of the circle, the relation between the distance and the radius is obtained by adopting the cosine law:
wherein, R is the radius of the ring array, and M is the number of the microphones.
Substituting the relation of the space sampling theorem into the space sampling theorem and solving the space sampling theorem to obtain:
the relationship of the radius R of the annular array of the microphone array, the number M of microphones and the wavelength λ of the microphone frequencies can be obtained.
Further, the center frequency of the optional microphone is in the range of 20KHz to 100KHz. In this embodiment, four microphones with different center frequencies are selected, namely, 20KHz, 30KHz, 40KHz and 50KHz, each microphone with 6 frequencies is provided, and the number of the microphones with each center frequency is 24, and the microphones with each center frequency are all arranged on an annular array with the same radius; it should be noted that the center frequency means that the microphone is more sensitive to ultrasonic waves at that frequency. The ultrasonic signal received by the acoustic microphone has lower relative frequency, the propagation attenuation is slow in the air, the advantage of long detection distance is achieved, and the receiving effect of the laser ultrasonic signal is improved.
Based on the foregoing calculation, to ensure that the microphone arrangement satisfies the spatial sampling theorem, we calculate the corresponding wavelength with the maximum center frequency of 50KHz of the microphone because the radius of the microphone matrix and the microphone pitch corresponding thereto are the smallest; meanwhile, in order to facilitate the arrangement and installation of the microphones, the microphones with all central frequencies are directly and uniformly arranged at the minimum distance required to be met, namely 50KHz and 24 microphones are substituted into the formula, the annular radius of the microphone array is 13.4mm, the distance is 3.4mm, the distance can meet the sampling requirement of four central frequency microphones, and the four microphones are sequentially and alternately arranged to form a uniform annular array. The detection personnel can also set the microphone arrangement mode of the microphone array according to the actual detection requirements and the microphone types, for example, microphones with different central frequencies are selected to form annular arrays with different radiuses, multi-plane microphone arrays and the like.
Further, the microphone types in the microphone array are various, including: a multi-band MEMS digital microphone, a multi-band MEMS analog microphone, a multi-band ECM analog microphone, and a multi-band ECM digital microphone. The size of the microphone can reach millimeter level, and the microphone has the advantage of small volume compared with an optical interferometer and a transducer.
For the air coupling probe, the receiving main frequency range of the air coupling probe can be selected to be 100KHz-2MHz. In this embodiment, the air coupling probe with four main frequencies of 100KHz, 500KHz, 1MHz and 2MHz is adopted, so that it can be understood that the working receiving frequency of the air coupling probe is just connected with the central frequency range of the microphone, the microphone array receives low frequency, the air coupling probe array receives high frequency, the effect of increasing the receiving range of the laser ultrasonic signal is realized, the receiving range of the ultrasonic wave band is increased, and the laser ultrasonic signal is more completely sampled.
Furthermore, the combined non-contact probe can realize beam forming in a phased array focusing mode, and the receiving range and the signal-to-noise ratio of the combined non-contact probe are further increased; and any one microphone or a microphone with specific frequency or an air coupling probe array can be controlled to receive signals, so that the undifferentiated detection of different defects of different materials is realized. The combined non-contact probe detects defects, and can detect the defects of a sample through the difference of the amplitude of a material signal and position the defects of the sample through a power spectrum; the combined non-contact probe has a large signal receiving range, and can receive signals generated by different material defects, so that the application range of the system is expanded.
Further, a signal processing module 50 is also arranged in the system; and the electric connection circuit is arranged between the combined non-contact probe and the computer and is used for preprocessing the laser ultrasonic signal received by the combined non-contact probe. The preprocessing of the signal processing module on the laser ultrasonic signal specifically comprises: filtering and amplifying. So that the detection personnel can carry out sound source positioning and defect detection on the laser ultrasonic signals, and the detection precision and efficiency are improved.
In this embodiment, through the microphone that adopts a plurality of different central frequencies to and with the air coupling probe of a plurality of different dominant frequencies, make combination formula non-contact probe can further adapt to the object of waiting to detect that thin is uneven, the frequency parameter of the probe of cooperation work in the regulation probe that can be quick has increased combination formula non-contact probe's detection range, increases the SNR, and set the microphone to the annular array of the interval that satisfies the space sampling theorem, has improved the sensitivity that the microphone detected.
The above is a detailed description of a second embodiment of the combined non-contact probe-based laser ultrasonic inspection system provided by the present application, and the following is a detailed description of a third embodiment of the combined non-contact probe-based laser ultrasonic inspection system provided by the present application.
Referring to fig. 3, fig. 3 is a schematic structural diagram of a signal processing module of the combined non-contact probe-based laser ultrasonic inspection system provided by the present application.
The signal processing module 50 preprocesses the laser ultrasonic signal received by the combined non-contact probe, and transmits the preprocessed laser ultrasonic signal to the computer, wherein the preprocessing includes amplification and filtering.
Further, the signal processing module 50 includes a multi-channel signal amplifying sub-module 51, a multi-channel signal filtering sub-module 52, a multi-channel signal collecting sub-module 53 and a signal data processing sub-module 54.
The multi-channel signal acquisition sub-module 53 is connected with the multi-channel signal filtering sub-module 52 and is used for receiving and storing the amplified and filtered laser ultrasonic signals;
the signal data processing submodule 54 is connected with the multi-channel signal acquisition submodule 53, and is used for realizing accurate detection of defects according to the difference of the signal amplitudes of the samples to be detected. And the thickness of the object to be detected can be calculated according to the time difference value of the surface signal and the bottom surface signal. And the defects of the sample can be positioned and detected according to the power spectrum.
The multi-channel signal acquisition sub-module is connected with the multi-channel signal filtering sub-module, and is used for receiving and storing the amplified and filtered laser ultrasonic signals and transmitting the laser ultrasonic signals to the computer 40.
The computer 40 detects the surface and the interior of the object to be detected according to the amplitude, the frequency, the transit time and the power spectrum of the laser ultrasonic signal. Realizing accurate detection of the defects according to the difference of the signal amplitude values at the defects of the sample to be detected; the thickness of the object to be detected can be calculated according to the time difference value of the surface signal and the bottom surface signal; the defects of the sample can be detected according to different main frequencies corresponding to different defects; the power spectrum can also be used to locate defects.
Further, the laser ultrasonic detection system can detect the defects by using a sound source positioning algorithm; the sound source positioning algorithm comprises time difference of arrival, beam synthesis and high-resolution spectrum estimation; the sound source positioning algorithm mainly uses power spectrum positioning, firstly, a search area is divided into a plurality of large areas, and the macroscopic position of a sound source is positioned in the areas by using ACO; then, a multi-signal classification algorithm is used for accurate searching and positioning, and finally, the accurate position of the sound source is estimated. Simulation and experiment show that: when the final searching steps are the same, the algorithm can greatly reduce the calculated amount in the positioning process, thereby greatly improving the calculation efficiency and the positioning accuracy on the premise of not reducing the positioning precision and meeting the requirement of real-time positioning imaging.
Further, the sound source localization principle is localization by using power spectrum. The power spectrum refers to the distribution of energy of a signal at various frequencies, and can be represented by the spatial spectrum of the signal. The algorithm based on high-resolution spectrum estimation is to form a matrix by the signals collected by the array microphone and obtain the incident angle and distance of the target sound source according to the spatial spectrum. The method mainly comprises a multi-signal classification algorithm. The basic idea of the multi-signal classification algorithm is to perform characteristic decomposition on a covariance matrix of sound data collected by an array microphone, so as to obtain two mutually orthogonal subspaces, namely a signal subspace and a noise subspace, wherein the signal subspace corresponds to a sound signal component. Based on the orthogonality of the two subspaces, the incident angle and signal strength of the acoustic signal can be estimated, and the position can be obtained.
In this embodiment, two blind hole defects may be prefabricated in the middle of the aluminum-carbon fiber laminated composite material, wherein the defect diameter is 4mm or 2mm. Through carrying out unfocused light beam detection on the front side opposite to the blind hole defect, receiving a laser ultrasonic signal and then carrying out image characterization on the aluminum-carbon fiber laminated composite material structure, the blind hole defect manufactured in the aluminum-carbon fiber laminated composite material can be well detected from an image characterization result.
The laser 10 has a current adjusting knob inside the power supply, and can control the intensity of the laser energy by controlling the current, specifically, it is a pulse laser with adjustable pulse width or a continuous laser with amplitude modulation, and can adjust the pulse width or change the modulation frequency according to the detection condition, so as to excite the ultrasonic signals with different frequencies.
The further laser adopts a pulse laser with adjustable pulse width; the laser wavelength of the laser is 532nm, the pulse width is 1-500ns and can be adjusted, and the maximum single pulse energy is 1.25mj. A continuous solid laser with wavelength of 532nm, maximum output power of 2000mW and modulation frequency of 1KHz-30KHz can also be used.
Further, the laser wavelength range emitted by the excitation laser in the laser 10 is between visible light and infrared light, the wavelength range of the emitted laser beam is between infrared light and visible light, namely within the range of 309nm-1000 μm, and the detection personnel can select and adjust the wavelength of the excited laser according to the material and the characteristics of the object to be detected; further, the pulse width of the pulse laser can be changed or the modulation frequency of the continuous laser can be changed to change the frequency of the laser ultrasonic signal; and the detection of different types of defects is realized by matching with microphones with different center frequencies.
In this embodiment, through setting up the laser ultrasonic detection system based on combination formula non-contact probe, the computer carries out analysis and judgment defect to laser ultrasonic signal, can be high-efficient and accurate judge the position of defect in waiting to detect the object to and carry out analysis and identification to the defect, have the advantage that efficient accuracy is high.
It can be clearly understood by those skilled in the art that, for convenience and brevity of description, the specific working process of the modules described above may refer to the corresponding process in the foregoing method embodiments, and is not described herein again.
In the several embodiments provided in the present application, it should be understood that the disclosed system may be implemented in other ways. For example, the above-described system embodiments are merely illustrative, and for example, the division of the units is only one logical functional division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit may be implemented in the form of hardware, or may also be implemented in the form of a software functional unit.
The above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. A laser ultrasonic detection system based on a combined non-contact probe is characterized by comprising:
the laser is electrically connected with the computer and used for emitting laser beams according to laser parameters set by the computer;
the laser scanning module is arranged between the laser and the object to be detected and is used for controlling the laser beam to scan the object to be detected;
the combined non-contact probe is electrically connected with the computer and is used for receiving the laser ultrasonic signal on the object to be detected and transmitting the laser ultrasonic signal to the computer; the combined non-contact probe includes: the device comprises a microphone, an air coupling probe and at least four substrates which are the same with the rotation center, wherein the same substrate is only provided with the microphone or the air coupling probe, and the distances from the microphone or the air coupling probe arranged on different substrates to the rotation center are different; there is at least one microphone on the substrate at a distance from the center of rotation that is greater than the distance from the air-coupled probe on one substrate to the center of rotation and less than the distance from the air-coupled probe on the other substrate to the center of rotation; the distance from the base plate of at least one air coupling probe to the rotation center is larger than that from the microphone on one base plate to the rotation center and smaller than that from the microphone on the other base plate to the rotation center;
and the computer is used for setting laser parameters for the laser and carrying out defect analysis on the laser ultrasonic signals received by the combined non-contact probe.
2. The combined non-contact probe-based laser ultrasonic detection system of claim 1, wherein the substrates are annular substrates, adjacent substrates are mutually matched, and each microphone and each air coupling probe are in the same plane.
3. The combined non-contact probe-based laser ultrasonic inspection system of claim 2, wherein the adjacent substrates are adapted to each other by: the outer diameter of one substrate between the adjacent annular substrates is equal to the inner diameter of the other substrate, and a bearing structure is arranged on the contact surface between the substrates.
4. The combined non-contact probe-based laser ultrasonic detection system of claim 1, wherein a plurality of air coupling probes with different main frequencies are arranged on the same substrate, and the distances between the air coupling probes on the same substrate and the rotation center are the same.
5. The combined non-contact probe-based laser ultrasonic testing system according to claim 1, wherein the receiving main frequency range of the air coupling probe is 100KHz-2MHz.
6. The combined non-contact probe-based laser ultrasonic detection system of claim 1, wherein a plurality of microphones with different center frequencies are arranged on the same substrate, and the distance between the microphones on the same substrate and the rotation center is the same.
7. The laser ultrasonic detection system based on the combined non-contact probe is characterized in that the microphones on the same substrate form a ring array around the rotation center, the microphone array is formed by alternately arranging microphones with various center frequencies, the number of the microphones with each center frequency is multiple, and the microphones with the same center frequency are uniformly distributed around the center of the microphone array.
8. The combined non-contact probe-based laser ultrasonic detection system of claim 7, wherein the distance between adjacent microphones satisfies the spatial sampling theorem, specifically:
wherein d is the distance between the microphones, and λ is the wavelength of the sound wave corresponding to the highest central frequency in the microphone array.
9. The combined non-contact probe-based laser ultrasound inspection system of claim 1, further comprising:
and the signal processing module is arranged on an electric connection circuit between the combined non-contact probe and the computer and is used for preprocessing the laser ultrasonic signal received by the combined non-contact probe.
10. The combined non-contact probe-based laser ultrasonic detection system according to claim 9, wherein the preprocessing of the laser ultrasonic signal by the signal processing module specifically comprises: filtering and amplifying.
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