Nonlinear ultrasonic guided wave detection system and method based on multi-channel reception

Abstract

This invention discloses a nonlinear ultrasonic guided wave detection system based on multi-channel reception, comprising a high-energy fundamental frequency ultrasonic excitation module, which generates an electrical signal under the control of a trigger signal and performs amplification and filtering; a transmitting transducer, which generates ultrasonic waves under the excitation of the high-energy fundamental frequency ultrasonic excitation module and acts on the target object; a variable angle receiving transducer array, which receives the ultrasonic guided wave signal fed back by the target object and converts it into a feedback electrical signal; an ultrasonic acquisition module, which, under the instruction of the control and signal processing module, amplifies and samples the feedback electrical signal and converts it into a digital signal; and a control and signal processing module, including an FPGA chip and an ARM main processor, which generates control instructions and performs time-domain, frequency-domain, and spatial-domain information extraction on the digital signal sent by the ultrasonic acquisition module, calculates the material nonlinear parameters carried by the guided wave signal, and performs micro-damage assessment and lifetime prediction based on the material nonlinear parameters.

Description

Technical Field

[0001] This invention belongs to the field of ultrasonic nondestructive testing technology, and particularly relates to a nonlinear ultrasonic guided wave testing system and method based on multi-channel reception. Background Technology

[0002] In industrial applications, metal components operating under high temperature and pressure environments inevitably suffer damage due to accumulated fatigue. Damage to metallic materials involves the process of micro-damage evolving into macro-damage, gradually affecting the overall safety and stability of the equipment. Therefore, accurately identifying early micro-damage in metal components is of great significance. According to research by scholars both domestically and internationally, microcracks, as a nonlinear factor, enhance the nonlinear effects of materials, and this nonlinear effect can be reflected using ultrasound. When ultrasound propagates in a medium, the waveform is distorted due to the nonlinearity of the medium, resulting in harmonic components in the acquired signal, thus forming nonlinear ultrasound. Therefore, studying the characteristics of nonlinear ultrasound can help evaluate the damage status of materials.

[0003] However, in actual measurements, the nonlinear components in the received ultrasonic guided wave signals are very weak. Furthermore, during measurement, the nonlinear effect is easily influenced by other nonlinear factors, such as contact pressure, the type of coupling agent, and the application method. In addition, the attenuation of ultrasonic guided waves propagating in plate or tubular materials is relatively large, making nonlinear guided waves difficult to detect.

[0004] When using nonlinear ultrasonic guided waves to detect micro-damage in materials, existing methods employ single-transmitter, single-receiver ultrasonic guided wave detection systems. Such systems typically excite ultrasonic waves at one end of the material under test (TUT) and receive them at the other. This approach suffers from problems such as low excitation energy, significant nonlinear harmonic interference at the excitation end, low receiving gain, and difficulty in resolving nonlinear signals. Furthermore, single-transmitter, single-receiver ultrasonic guided wave detection systems can only measure the average damage level within a certain range in a single measurement, failing to analyze damage at individual locations and making it difficult to extract comprehensive information about the TUT across the time, frequency, and spatial domains. Detecting damage at different locations requires continuous probe adjustment, leading to low measurement efficiency and introducing measurement errors. Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to provide a nonlinear ultrasonic guided wave detection system and method based on multi-channel reception. This system excites ultrasonic waves with harmonic suppression characteristics and, through multi-channel reception and variable gain, simultaneously extracts time-domain, frequency-domain, and spatial-domain information of nonlinear harmonics at different locations of the material under test for comprehensive analysis. Thus, under the condition of a single ultrasonic excitation, it can detect the test area within different ranges, thereby reflecting the degree of damage, spatial location of damage, and life prediction of the material under test.

[0006] The technical solution provided by this invention is: a nonlinear ultrasonic guided wave detection system based on multi-channel reception, comprising:

[0007] The high-energy fundamental frequency ultrasonic excitation module generates an electrical signal controlled by a trigger signal and then amplifies and filters it.

[0008] The transmitting transducer, under the excitation of the high-energy fundamental frequency ultrasonic excitation module, generates ultrasonic waves that act on the target object;

[0009] A variable-angle receiving transducer array is used to receive ultrasonic guided wave signals fed back by the target object and convert them into feedback electrical signals;

[0010] The ultrasonic acquisition module, under the instruction of the control and signal processing module, is used to amplify the feedback electrical signal, sample it, and convert it into a digital signal.

[0011] The control and signal processing module, including an FPGA chip and an ARM main processor, is used to generate control instructions and extract information in the time domain, frequency domain, and spatial domain from the digital signals sent by the ultrasonic acquisition module. It calculates the material nonlinear parameters carried by the guided wave signal and performs micro-damage assessment and lifetime prediction based on these material nonlinear parameters.

[0012] Preferably, the high-energy fundamental frequency ultrasonic excitation module further includes a signal generator, a linear power amplifier, and a low-pass analog filter. The signal generator is controlled by a trigger signal to generate a Hanning window modulated high-energy multi-cycle sinusoidal electrical signal. The linear power amplifier amplifies the high-energy multi-cycle sinusoidal electrical signal. The low-pass analog filter filters the amplified electrical signal to suppress harmonic components.

[0013] Preferably, the high-energy, multi-cycle sinusoidal electrical signal modulated by the Hanning window and controlled by the trigger signal is generated by the signal generator in the following manner:

[0014]

[0015] Where A is the amplitude and f is the center frequency of the sine wave. It is the Hanning window envelope, and T is the total time length.

[0016] Preferably, the variable angle receiving transducer array includes a cuboid shell, a cylindrical wedge disposed inside the cuboid shell, a receiving transducer array fixed inside the cylindrical wedge, and a knob disposed on one end face of the cylindrical wedge. The receiving transducer array is parallel to a diameter of the cross-section of the cylindrical wedge. The knob is eccentrically disposed on the end face of the cylindrical wedge. The cuboid shell is provided with an arc-shaped track for the knob to move. Coupling agent is filled between the cuboid shell and the cylindrical wedge.

[0017] Preferably, the ultrasound acquisition module includes a low-noise amplifier, a programmable attenuator, a programmable gain amplifier, a time gain compensation unit, and an analog-to-digital converter. The programmable attenuator and the programmable gain amplifier each have multiple adjustable levels. The control and signal processing module adjusts the gain of the programmable attenuator and the programmable gain amplifier of the ultrasound acquisition module.

[0018] Preferably, the ultrasonic acquisition module, under the instruction of the control and signal processing module, amplifies and samples the feedback electrical signal, converts it into a digital signal, and then outputs it for subsequent signal processing. The ultrasonic acquisition module includes an analog front-end chip, a data acquisition module, a communication module, and a power supply module. The analog front-end chip performs preliminary processing on the received signal. The chip integrates low-noise amplification, programmable attenuation, and programmable gain amplification functions, and is controlled by the instruction of the control and signal processing module to realize variable gain amplification of the signal.

[0019] Preferably, the control and signal processing module receives the digital signal sent by the ultrasound acquisition module and calculates the amplitude spectrum and nonlinear parameters of the received signal from each receiving channel, further including:

[0020] Solving the nonlinear wave equation yields the wave propagation formulas at different locations:

[0021]

[0022] Where u is displacement, β is second-order nonlinear parameter, w is frequency, k is wave number, and A is fundamental amplitude;

[0023] According to the formula for the amplitude B of the second harmonic:

[0024]

[0025] The calculated nonlinear parameter vector β is expressed as:

[0026]

[0027] Based on the same concept, the present invention also provides a nonlinear ultrasonic guided wave detection method based on multi-channel reception, comprising the following steps:

[0028] A high-energy, multi-cycle sinusoidal electrical signal modulated by a Hanning window is generated under the control of a preset trigger signal. After linear power amplification, an ultrasonic electrical signal is generated, and high-frequency components are filtered out before acting on the target object.

[0029] The ultrasonic guided wave signal transmitted by the target object is received by a variable angle receiving transducer array and converted into a feedback electrical signal.

[0030] The feedback electrical signal is amplified with low noise, programmably attenuated, programmably gained, time-gain compensated, and quantized into a digital signal using an ultrasonic acquisition module.

[0031] The amplitude spectrum and nonlinear parameters of the received signals of each receiving channel are calculated. The nonlinear parameters are compared with the relationship between the nonlinear parameters and the degree of damage, and the relationship between the nonlinear parameters and the lifetime of the target material in the standard database, so as to obtain the degree of damage of the material under test and perform lifetime prediction.

[0032] Preferably, calculating the amplitude spectrum and nonlinear parameters of the received signal for each receiving channel further includes:

[0033] Solving the nonlinear wave equation yields the wave propagation formulas at different locations:

[0034]

[0035] Where u is displacement, β is second-order nonlinear parameter, w is frequency, k is wave number, and A is fundamental amplitude;

[0036] According to the formula for the amplitude B of the second harmonic:

[0037]

[0038] The calculated nonlinear parameter vector β is expressed as:

[0039]

[0040] Based on the same concept, the present invention also provides a readable storage medium storing a processing program, which, when executed by a processor, implements the detection method described in any one of the above claims.

[0041] Because the present invention adopts the above technical solution, it has the following advantages and positive effects compared with the prior art:

[0042] A nonlinear ultrasonic guided wave detection system based on multi-channel reception achieves in-depth assessment of the internal state of materials through efficient signal generation, flexible signal reception, precise signal processing, and powerful data processing capabilities. This not only helps in the timely detection of potential micro-damage in materials but also predicts the remaining lifespan of materials, providing a scientific basis for maintenance and replacement, and significantly improving the reliability and practicality of the detection technology. Employing a single-channel excitation and multi-channel simultaneous reception method, the variable-angle receiving transducer array containing multiple array elements can simultaneously extract time-domain, frequency-domain, and spatial domain information of nonlinear harmonics at different locations of the material under test, thereby obtaining the damage degree, damage spatial location, and lifespan prediction of the material under test. A single acquisition can extract nonlinear characteristics at different locations, improving acquisition efficiency and reducing measurement errors. Attached Figure Description

[0043] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, wherein:

[0044] Figure 1 This is a structural diagram of the nonlinear ultrasonic guided wave detection system based on multi-channel reception of the present invention;

[0045] Figure 2 This is a structural diagram of an ultrasonic acquisition module according to an embodiment of the present invention;

[0046] Figure 3 This is a structural diagram of an ultrasonic acquisition module according to an embodiment of the present invention;

[0047] Figure 4 This is a schematic diagram of a high-energy multi-cycle sinusoidal electrical signal modulated by the high-energy Hanning window of the present invention;

[0048] Figure 5 The cumulative effect curve and fitting results of the aluminum plate 1 material of the present invention are shown below;

[0049] Figure 6 The cumulative effect curve and fitting results of the aluminum plate 2 material of the present invention are shown.

[0050] Figure 7 This is a variable angle receiving transducer array according to one embodiment of the present invention. Detailed Implementation

[0051] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer from the following description and claims. It should be noted that the drawings are all in a very simplified form and use non-precise ratios, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0052] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0053] First Embodiment

[0054] like Figure 1 The diagram shows a structural diagram of a nonlinear ultrasonic guided wave detection system based on multi-channel reception, including a high-energy fundamental frequency ultrasonic excitation module, a transmitting transducer, a variable angle receiving transducer array, an ultrasonic acquisition module, a control and signal processing module, and a power supply module.

[0055] The high-energy fundamental frequency ultrasonic excitation module generates an electrical signal controlled by a trigger signal and then amplifies and filters it.

[0056] The transmitting transducer is mounted on the material under test by a wedge and generates ultrasonic waves under the excitation of the high-energy fundamental frequency ultrasonic excitation module, which then act on the target object.

[0057] A variable-angle receiving transducer array is installed on the material under test. The angle is adjusted to match the ultrasonic guided wave excitation angle. It is used to receive the ultrasonic guided wave signal fed back by the target object and convert it into a feedback electrical signal, thereby simultaneously extracting the time-frequency-spatial domain information of nonlinear harmonics at different positions of the material under test.

[0058] The ultrasonic acquisition module, under the instruction of the control and signal processing module, is used to amplify the feedback electrical signal, sample it, and convert it into a digital signal.

[0059] The control and signal processing module, including an FPGA chip and an ARM main processor, is used to generate control instructions and extract information in the time domain, frequency domain, and spatial domain from the digital signals sent by the ultrasonic acquisition module. It calculates the material nonlinear parameters carried by the guided wave signal and performs micro-damage assessment and lifetime prediction based on these material nonlinear parameters.

[0060] A nonlinear ultrasonic guided wave detection system based on multi-channel reception achieves in-depth assessment of the internal state of materials through efficient signal generation, flexible signal reception, precise signal processing, and powerful data processing capabilities. This not only helps in the timely detection of potential micro-damage in materials but also predicts the remaining lifespan of materials, providing a scientific basis for maintenance and replacement, and significantly improving the reliability and practicality of the detection technology. Employing a single-channel excitation and multi-channel simultaneous reception method, the variable-angle receiving transducer array containing multiple array elements can simultaneously extract time-domain, frequency-domain, and spatial domain information of nonlinear harmonics at different locations of the material under test, thereby obtaining the damage degree, damage spatial location, and lifespan prediction of the material under test. A single acquisition can extract nonlinear characteristics at different locations, improving acquisition efficiency and reducing measurement errors.

[0061] Specifically, the high-energy fundamental frequency ultrasonic excitation module includes: a signal generator, a linear power amplifier, and a low-pass analog filter. The signal generator, an arbitrary waveform generator, is connected to the ultrasonic acquisition module and is used to generate a high-energy Hanning window modulated high-energy multi-cycle sinusoidal electrical signal based on the trigger signal and configuration instructions of the ultrasonic acquisition module, while suppressing harmonic components. The linear power amplifier uses a push-pull output circuit with PMOS and NMOS transistors that have symmetrical and high-current drive capabilities, and employs a diode unidirectional conduction circuit for isolation protection. The low-pass analog filter can effectively filter out high-frequency interference components from the high-energy fundamental frequency ultrasonic excitation module.

[0062] More specifically, the high-energy, multi-cycle sinusoidal electrical signal modulated by the Hanning window generated by the signal generator is generated by the signal generator in the following manner:

[0063]

[0064] Where A is the amplitude and f is the center frequency of the sine wave. It is the Hanning window envelope, and T is the total time length.

[0065] In one embodiment, the signal generator excites a high-energy, multi-cycle sinusoidal electrical signal modulated by a Hanning window with 20 pulses, a peak-to-peak value of 100V, and a frequency of approximately 2.4MHz.

[0066] The transmitting transducer is mounted on the plate-shaped or tubular material under test via a wedge. The angle of the wedge can be adjusted according to specific needs; in one embodiment, the wedge angle is set to 24°. It is used to transmit a Hanning window modulated high-energy, multi-cycle sinusoidal signal to the material under test under the excitation of an ultrasonic electrical signal.

[0067] See Figure 7The variable-angle receiving transducer array includes a cuboid shell, a cylindrical wedge disposed inside the cuboid shell, a receiving transducer array fixed inside the cylindrical wedge, and a knob disposed on one end face of the cylindrical wedge. The receiving transducer array is parallel to a diameter of the cross-section of the cylindrical wedge. The knob is eccentrically positioned on the end face of the cylindrical wedge. The cuboid shell has an arc-shaped track for moving the knob. Coupling agent is filled between the cuboid shell and the cylindrical wedge. Preferably, the variable-angle receiving transducer array can be adjusted within the range of 0°-45°. By adjustment, it can be matched with the excitation angle of the ultrasonic guided wave, resulting in fewer modes generated by the ultrasonic guided wave, which is beneficial for the extraction of nonlinear harmonic signals. The variable angle allows the receiving transducer array to adapt to different measurement angles, providing wider applicability compared to traditional planar receiving transducer arrays.

[0068] Furthermore, the receiving transducer array comprises multiple elements, typically 64 or 128 elements, mounted on the material under test. By adjusting its angle to match the excitation angle of the ultrasonic guided wave, it receives the ultrasonic guided wave signal fed back from the material under test and converts it into a feedback electrical signal, thereby simultaneously extracting time-domain, frequency-domain, and spatial-domain information of nonlinear harmonics at different locations on the material under test. The variable-angle receiving transducer array can be controlled by any adjustment structure to adjust its angle, thereby achieving the extraction of time-domain, frequency-domain, and spatial-domain information of nonlinear harmonics at different locations on the material under test.

[0069] See Figure 2 In one embodiment, the ultrasound acquisition module includes a low-noise amplifier, a programmable attenuator, a programmable gain amplifier, a time gain compensation unit, and an analog-to-digital converter. Under the instructions of the control and signal processing module, the feedback electrical signal is amplified and then sampled to convert it into a digital signal. In one embodiment, the low-noise amplifier is a single-ended input differential output operational amplifier, and the overall gain is adjustable in three levels: 15dB, 18dB, and 21dB, by programming the resistance value of the feedback resistor. The programmable attenuator achieves attenuation from 0-36dB through a voltage divider network composed of fixed and variable resistors. The input terminal of the programmable gain amplifier is connected to the programmable attenuator, allowing for three levels of adjustment: 21dB, 24dB, and 27dB. Ultimately, the ultrasound acquisition module can achieve a maximum overall gain of 48dB. Preferably, the low-noise amplifier gain is set to 21dB, the programmable gain amplifier gain is set to 27dB, and the overall gain is 48dB. The target gain is achieved by adjusting relevant parameters such as the excitation frequency, number of cycles, center frequency, and delay of the ultrasound receiving chip, as well as the gain at each level. It effectively solves the problem of difficult analysis caused by weak nonlinear harmonic signals, and different gain configurations can be applied to the needs of different scenarios.

[0070] The ultrasound acquisition module, controlled by the control and signal processing module, amplifies and samples the feedback electrical signal, converts it into a digital signal, and then outputs it for subsequent signal processing; see also Figure 3 In one embodiment, the ultrasound acquisition module includes an analog front-end chip, a data acquisition module, a communication module, and a power supply module. The analog front-end chip performs preliminary processing on the received signal. The chip integrates low-noise amplification, programmable attenuation, and programmable gain amplification functions, and is controlled by the instructions of the control and signal processing module to achieve variable gain amplification of the signal.

[0071] The control and signal processing module, including an FPGA chip and an ARM main processor, is used to generate control instructions and extract information from the ultrasonic acquisition signal in the time domain, frequency domain, and spatial domain to obtain the material nonlinear parameters carried by the guided wave signal. Then, based on the nonlinear parameters of the material, micro-damage assessment and lifetime prediction are performed.

[0072] Specifically, a program runs within the ARM main processor and executes:

[0073] Set the delay and gain of the ultrasound acquisition module;

[0074] Based on the processed guided wave signal, the material nonlinear parameters carried by the guided wave signal are calculated, and the damage assessment results and lifetime prediction of the material under test at different locations are obtained based on the nonlinear parameters.

[0075] The FPGA chip receives control commands from the ARM main processor and controls the ultrasonic acquisition module to work through the SPI bus and I / O ports.

[0076] The process by which the ARM main processor calculates the material nonlinear parameters carried by the processed guided wave signal specifically includes:

[0077] First, solve the nonlinear wave equation to obtain the wave propagation formulas at different locations:

[0078]

[0079] Where u is displacement, β is a second-order nonlinear parameter, w is frequency, k is wave number, and A is the fundamental amplitude.

[0080] According to the formula for the amplitude B of the second harmonic:

[0081]

[0082] The calculated nonlinear parameter vector β is expressed as:

[0083]

[0084] Based on the above derivation process, Figure 5 and Figure 6 The cumulative effect curves and fitting results for two aluminum plates are shown, illustrating the normalized nonlinear parameters and their trends (i.e., cumulative effect) at different locations from the transmitter transducer probe. By comparing and analyzing the slopes of the cumulative effect fitting curves for the two aluminum plates, it can be determined that the average damage degree of aluminum plate 1 is less than that of aluminum plate 2.

[0085] The ARM main processor has a built-in program that extracts information from the ultrasonic acquisition signal in the time, frequency, and spatial domains to obtain the material nonlinear parameters carried by the guided wave signal. Based on these nonlinear parameters, micro-damage assessment and lifetime prediction are then performed. The FPGA chip receives control commands from the ARM main processor to control the high-energy fundamental frequency ultrasonic excitation module and the ultrasonic acquisition module, providing instructions for timing logic, delay configuration, and gain settings. The detection of damage at different locations in the material under test includes: performing a Fast Fourier Transform on the restored guided wave signals measured from different channels to obtain the amplitude spectrum, calculating the ratio of harmonic amplitude to the square of the fundamental amplitude to obtain the material nonlinear parameters, and comparing the changes in nonlinear parameters at different locations with a standard database to reflect the damage status at different locations in the material under test.

[0086] The power module is used to supply power to the above-mentioned modules, providing different digital voltages to drive the FPGA chip and positive and negative symmetrical reference voltages required by the ultrasonic acquisition module.

[0087] Preferably, an ultrasonic coupling agent is also provided between the transducer and the wedge, between the wedge and the material under test, and between the material under test and the variable-angle receiving transducer array. There are no particular limitations on the material under test; it can be metal, composite material, bone plate, etc. In this embodiment, a square aluminum plate with a side length of 0.5 meters and a thickness of 1.5 millimeters is selected as the material under test for the experiment.

[0088] Second Embodiment

[0089] Based on the same concept, the present invention also provides a nonlinear ultrasonic guided wave detection method based on multi-channel reception, comprising the following steps:

[0090] A high-energy, multi-cycle sinusoidal electrical signal modulated by a Hanning window is generated under the control of a preset trigger signal. After linear power amplification, an ultrasonic electrical signal is generated, and high-frequency components are filtered out before acting on the target object.

[0091] The ultrasonic guided wave signal transmitted by the target object is received by a variable-angle receiving transducer array and converted into an electrical signal.

[0092] The electrical signal is amplified with low noise, programmably attenuated, programmably gained, time-gain compensated, and quantized into a digital signal using an ultrasonic acquisition module.

[0093] The amplitude spectrum and nonlinear parameters of the received signals of each receiving channel are calculated. The nonlinear parameters are compared with the relationship between the nonlinear parameters and the degree of damage, and the relationship between the nonlinear parameters and the lifetime of the target material in the standard database, so as to obtain the degree of damage of the material under test and perform lifetime prediction.

[0094] High-energy, multi-cycle sinusoidal electrical signals modulated by the Hanning window can effectively improve the penetration and detection depth of ultrasound, effectively solving the problems of low excitation energy and harmonic interference in traditional equipment, and improving the accuracy of nonlinear components in the results. This enhances the accuracy and reliability of the detection. Employing a variable-angle receiving transducer array enables omnidirectional, multi-angle detection of the target object, improving the comprehensiveness and flexibility of the detection. The ultrasonic acquisition module's low-noise amplification, programmable attenuation, programmable gain, and time gain compensation functions improve signal quality, reduce noise interference, and make the detection results more accurate and reliable. By calculating the amplitude spectrum and nonlinear parameters of the received signals from each receiving channel, information such as the degree of damage and lifespan prediction within the material can be revealed, providing a basis for material maintenance and replacement. Comparing the calculated nonlinear parameters with the relationships between nonlinear parameters and damage degree, and between nonlinear parameters and lifespan of the target object in a standard database can further improve the accuracy and reliability of the detection, providing a more scientific basis for material maintenance and replacement.

[0095] Preferably, calculating the amplitude spectrum and nonlinear parameters of the received signal for each receiving channel further includes:

[0096] Solving the nonlinear wave equation yields the wave propagation formulas at different locations:

[0097]

[0098] Where u is displacement, β is second-order nonlinear parameter, w is frequency, k is wave number, and A is fundamental amplitude;

[0099] According to the formula for the amplitude B of the second harmonic:

[0100]

[0101] The calculated nonlinear parameter vector β is expressed as:

[0102]

[0103] The process of evaluating the micro-damage of the material under test is described below:

[0104] The signal generator generates a high-energy, multi-cycle sinusoidal electrical signal with the required frequency and amplitude modulated by a Hanning window according to the external trigger signal provided by the ultrasonic acquisition module. The signal is then amplified by a linear power amplifier to generate an ultrasonic electrical signal.

[0105] The low-pass analog filter in the high-energy fundamental frequency ultrasonic excitation module is responsible for filtering out high-frequency components, while the transmitting transducer is responsible for transmitting a Hanning window modulated high-energy multi-cycle sinusoidal electrical signal to the material under test. This signal is transmitted to the plate-shaped or tubular material under test through a wedge and an ultrasonic coupling agent, and the ultrasound propagates in the material under test to generate ultrasonic guided waves.

[0106] The 64-element variable angle receiving transducer array receives the ultrasonic guided wave signal transmitted from the material under test and converts it into an electrical signal.

[0107] The ultrasonic acquisition chip performs low-noise amplification, programmable attenuation, programmable gain, time gain compensation, and quantization on the electrical signal according to the instructions of the FPGA, converting it into a digital signal.

[0108] The FPGA chip reads the digital signal through the LVDS high-speed data transmission interface, and after averaging it multiple times, sends the data to the ARM main processor via SPI for further processing.

[0109] The ARM main processor performs preprocessing such as digital filtering on the received 64-channel signal, and then calculates the amplitude spectrum and nonlinear parameters of the received signal in each channel, i.e., the nonlinear parameters at different locations of the material under test. Then, the experimentally measured nonlinear parameters are compared with the relationships between nonlinear parameters and damage degree, and between nonlinear parameters and lifetime in a standard database, to obtain the damage degree of the material under test and to predict its lifetime.

[0110] Based on the same concept, the present invention also provides an electronic device, comprising: a memory for storing a processing program; and a processor, wherein the processor, when executing the processing program, implements the nonlinear ultrasonic guided wave detection method based on multi-channel reception described above.

[0111] Based on the same concept, the present invention also provides a readable storage medium storing a processing program, which, when executed by a processor, implements the nonlinear ultrasonic guided wave detection method based on multi-channel reception described above.

[0112] If the nonlinear ultrasonic guided wave detection method based on multi-channel reception is implemented in the form of program instructions and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this embodiment, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in software form. This computer software is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this disclosure. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0113] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific identification content executed by the system and device described above can be referred to the corresponding process in the foregoing method embodiments.

[0114] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, if these changes fall within the scope of the claims of the present invention and their equivalents, they shall still fall within the protection scope of the present invention.

Claims

1. A nonlinear ultrasonic guided wave detection system based on multi-channel reception, characterized in that, include: The high-energy fundamental frequency ultrasonic excitation module generates an electrical signal controlled by a trigger signal and then amplifies and filters it. The transmitting transducer, under the excitation of the high-energy fundamental frequency ultrasonic excitation module, generates ultrasonic waves that act on the target object; A variable-angle receiving transducer array is used to receive ultrasonic guided wave signals fed back by the target object and convert them into feedback electrical signals. The variable-angle receiving transducer array includes a cuboid shell, a cylindrical wedge disposed inside the cuboid shell, a receiving transducer array fixed inside the cylindrical wedge, and a knob disposed on one end face of the cylindrical wedge. The receiving transducer array is parallel to a diameter of the cross-section of the cylindrical wedge. The knob is eccentrically disposed on the end face of the cylindrical wedge. An arc-shaped track for moving the knob is provided on the cuboid shell. Coupling agent is filled between the cuboid shell and the cylindrical wedge. The ultrasonic acquisition module, under the instruction of the control and signal processing module, is used to amplify the feedback electrical signal, sample it, and convert it into a digital signal. The control and signal processing module, including an FPGA chip and an ARM main processor, is used to generate control instructions and extract information in the time domain, frequency domain, and spatial domain from the digital signals sent by the ultrasonic acquisition module. It calculates the material nonlinear parameters carried by the guided wave signal and performs micro-damage assessment and lifetime prediction based on these material nonlinear parameters.

2. The nonlinear ultrasonic guided wave detection system based on multi-channel reception according to claim 1, characterized in that, The high-energy fundamental frequency ultrasonic excitation module further includes a signal generator, a linear power amplifier, and a low-pass analog filter. The signal generator is controlled by a trigger signal to generate a high-energy multi-cycle sinusoidal electrical signal modulated by a Hanning window. The linear power amplifier amplifies the high-energy multi-cycle sinusoidal electrical signal. The low-pass analog filter filters the amplified electrical signal to suppress harmonic components.

3. The nonlinear ultrasonic guided wave detection system based on multi-channel reception according to claim 2, characterized in that, The high-energy, multi-cycle sinusoidal electrical signal modulated by the Hanning window and controlled by the trigger signal is generated by the signal generator in the following manner: ， Where A is the amplitude. It is the center frequency of the sine wave. It is the Hanning window envelope, and T is the total time length.

4. The nonlinear ultrasonic guided wave detection system based on multi-channel reception according to claim 1, characterized in that, The ultrasound acquisition module includes a low-noise amplifier, a programmable attenuator, a programmable gain amplifier, a time gain compensation unit, and an analog-to-digital converter. The programmable attenuator and the programmable gain amplifier each have multiple adjustable levels. The control and signal processing module adjusts the gain of the programmable attenuator and the programmable gain amplifier of the ultrasound acquisition module.

5. The nonlinear ultrasonic guided wave detection system based on multi-channel reception according to claim 4, characterized in that, The ultrasonic acquisition module, controlled by the control and signal processing module, amplifies and samples the feedback electrical signal, converts it into a digital signal, and then outputs it for subsequent signal processing. The ultrasonic acquisition module includes an analog front-end chip, a data acquisition module, a communication module, and a power supply module. The analog front-end chip performs preliminary processing on the received signal. The chip integrates low-noise amplification, programmable attenuation, and programmable gain amplification functions, and is controlled by the control and signal processing module to achieve variable gain amplification of the signal.

6. The nonlinear ultrasonic guided wave detection system based on multi-channel reception according to claim 1, characterized in that, The control and signal processing module receives the digital signals sent by the ultrasound acquisition module and calculates the amplitude spectrum and nonlinear parameters of the received signals from each receiving channel, further including: Solving the nonlinear wave equation yields the wave propagation formulas at different locations: Where u is displacement, β is second-order nonlinear parameter, w is frequency, k is wave number, and A is fundamental amplitude; According to the formula for the amplitude B of the second harmonic: ， The nonlinear parameter vector is calculated. Represented as: 。 7. A nonlinear ultrasonic guided wave detection method based on multi-channel reception, characterized in that, Includes the following steps: A high-energy, multi-cycle sinusoidal electrical signal modulated by a Hanning window is generated under the control of a preset trigger signal. After linear power amplification, an ultrasonic electrical signal is generated, and high-frequency components are filtered out before acting on the target object. The ultrasonic guided wave signal transmitted by the target object is received by a variable angle receiving transducer array and converted into a feedback electrical signal; the variable angle receiving transducer array includes a cuboid shell, a cylindrical wedge block disposed inside the cuboid shell, a receiving transducer array fixed inside the cylindrical wedge block, and a knob disposed on one end face of the cylindrical wedge block. The receiving transducer array is parallel to a diameter of the cross-section of the cylindrical wedge block. The knob is eccentrically disposed on the end face of the cylindrical wedge block. An arc-shaped track for the knob to move is provided on the cuboid shell. Coupling agent is filled between the cuboid shell and the cylindrical wedge block. The feedback electrical signal is amplified with low noise, programmably attenuated, programmably gained, time-gain compensated, and quantized into a digital signal using an ultrasonic acquisition module. The amplitude spectrum and nonlinear parameters of the received signals of each receiving channel are calculated. The nonlinear parameters are compared with the relationship between the nonlinear parameters and the degree of damage, and the relationship between the nonlinear parameters and the lifetime of the target material in the standard database, so as to obtain the degree of damage of the material under test and perform lifetime prediction.

8. The nonlinear ultrasonic guided wave detection method based on multi-channel reception according to claim 7, characterized in that, The calculation of the amplitude spectrum and nonlinear parameters of the received signal for each receiving channel further includes: Solving the nonlinear wave equation yields the wave propagation formulas at different locations: Where u is displacement, β is second-order nonlinear parameter, w is frequency, k is wave number, and A is fundamental amplitude; According to the formula for the amplitude B of the second harmonic: ， The nonlinear parameter vector is calculated. Represented as: 。 9. A readable storage medium, characterized in that, The readable storage medium stores a processing program, which, when executed by a processor, implements the detection method according to any one of claims 7 to 8.

Images