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

Abstract

The invention discloses a nonlinear ultrasonic guided wave detection system based on multi-channel receiving, and the system comprises a high-energy fundamental frequency ultrasonic excitation module which is controlled by a trigger signal to generate an electric signal and carries out the amplification and filtering processing; the transmitting transducer generates ultrasonic waves to act on a target object under the excitation of the high-energy fundamental frequency ultrasonic excitation module; the variable-angle receiving transducer array is used for receiving the ultrasonic guided wave signal fed back by the target object and converting the ultrasonic guided wave signal into a feedback electric signal; the ultrasonic acquisition module is used for amplifying the feedback electric signal, sampling the feedback electric signal and converting the feedback electric signal into a digital signal under the instruction of the control and signal processing module; the control and signal processing module comprises an FPGA (Field Programmable Gate Array) chip and an ARM (Advanced RISC Machines) main processor, and is used for controlling the generation of an instruction and performing time domain-frequency domain-space domain information extraction on the digital signal sent by the ultrasonic acquisition module, and calculating to obtain a material nonlinear parameter carried by the guided wave signal; and performing micro-damage evaluation and life prediction based on the nonlinear parameters of the material.

Description

Technical Field

[0001] The present invention belongs to the technical field of ultrasonic nondestructive testing, and in particular relates to a nonlinear ultrasonic guided wave testing system and method based on multi-channel reception. Background Art

[0002] In the industrial field, metal components serving in high temperature and high pressure environments will inevitably be damaged due to the accumulation of fatigue. Metal material damage includes the process of evolving from micro-damage to macro-damage, which gradually affects the overall safety and stability of the equipment. Therefore, it is of great significance to accurately identify early micro-damage of metal components. According to the research of domestic and foreign scholars, microcracks, as a nonlinear factor, will enhance the nonlinear effect of the material, and this nonlinear effect can be reflected by ultrasonic methods. When ultrasound propagates in the medium, the waveform is distorted due to the existence of medium nonlinearity, so the collected signal will have harmonic components and form nonlinear ultrasound. Therefore, by studying the characteristics of nonlinear ultrasound, the damage of the material can be evaluated.

[0003] However, in actual measurement, the nonlinear component of the received ultrasonic guided wave signal is very weak. Moreover, during measurement, the nonlinear effect is easily affected by other nonlinear factors, such as contact pressure, type of coupling agent and application method, etc. In addition, the attenuation of ultrasonic guided waves propagating in plate-like or tubular materials is relatively large, making nonlinear guided waves difficult to detect.

[0004] When using nonlinear ultrasonic guided waves to detect micro-damage of materials, the existing method is to use a single-transmitter and single-receiver ultrasonic guided wave detection system. Such a guided wave detection system usually excites ultrasonic waves at one end of the material to be tested and receives ultrasonic waves at the other end of the material to be tested. There will be problems such as low excitation energy, large nonlinear harmonic interference signals generated at the excitation end, low receiving gain, and difficulty in analyzing nonlinear signals. In addition, based on a single-transmitter and single-receiver ultrasonic guided wave detection system, a single measurement can only detect the average value of the degree of damage within a certain range, and cannot analyze the damage conditions at each position, making it difficult to extract comprehensive information of the material to be tested in the time domain, frequency domain, and space domain. If the damage conditions at different positions are detected, the position of the probe needs to be constantly adjusted, which not only has low measurement efficiency, but also introduces measurement errors. Summary of the invention

[0005] To solve the above problems, the purpose of the present invention is to provide a nonlinear ultrasonic guided wave detection system and method based on multi-channel reception, which excites ultrasonic waves with harmonic suppression characteristics, and through multi-channel reception and variable gain methods, simultaneously extracts the time domain-frequency domain-space domain information of nonlinear harmonics at different positions of the material to be tested for comprehensive analysis. Therefore, under the condition of single ultrasonic excitation, the test areas within different ranges can be detected, thereby reflecting the damage degree, spatial position of the damage and life prediction of the material to be tested.

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

[0007] The high-energy fundamental frequency ultrasonic excitation module is controlled by the trigger signal to generate an electrical signal and perform amplification and filtering processing;

[0008] A transmitting transducer, which generates ultrasonic waves to act on a target object under the stimulation of the high-energy fundamental frequency ultrasonic excitation module;

[0009] A variable angle receiving transducer array, used for receiving the ultrasonic guided wave signal fed back by the target object and converting it into a feedback electrical signal;

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

[0011] The control and signal processing module, which includes an FPGA chip and an ARM main processor, is used to generate control instructions and extract information in the time domain, frequency domain and space domain from the digital signal sent by the ultrasonic acquisition module, calculate the nonlinear parameters of the material carried by the guided wave signal, and perform micro-damage assessment and life prediction based on the nonlinear parameters of the material.

[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 high-energy multi-cycle sinusoidal electrical signal modulated by a Hanning window. The linear power amplifier performs power amplification processing on the high-energy multi-cycle sinusoidal electrical signal. The low-pass analog filter filters the amplified electrical signal to suppress the harmonic components therein.

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

[0014]

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

[0016] Preferably, the variable-angle receiving transducer array includes a rectangular shell, a cylindrical wedge disposed inside the rectangular 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 rectangular shell is provided with an arc track for the knob to move, and a coupling agent is filled between the rectangular shell and the cylindrical wedge.

[0017] Preferably, the ultrasonic 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 respectively have multiple adjustment levels. The control and signal processing module adjusts the gain of the programmable attenuator and the programmable gain amplifier of the ultrasonic acquisition module.

[0018] Preferably, the ultrasonic acquisition module is controlled by the instructions of the control and signal processing module to first amplify and then sample the feedback electrical signal, convert it into a digital signal and then output 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, wherein the analog front-end chip performs preliminary processing on the received signal, and 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.

[0019] Preferably, the control and signal processing module receives the digital signal sent by the ultrasonic acquisition module to calculate the amplitude spectrum and nonlinear parameters of the received signal of each receiving channel, further comprising:

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

[0021]

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

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

[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] Controlled by a preset trigger signal, a high-energy multi-cycle sinusoidal electrical signal modulated by a Hanning window is generated, and an ultrasonic electrical signal is generated after linear power amplification, and the high-frequency components are filtered out to act on the target object;

[0029] receiving the ultrasonic guided wave signal transmitted by the target object through a variable angle receiving transducer array and converting it into a feedback electrical signal;

[0030] The feedback electrical signal is subjected to low-noise amplification, programmable attenuation, programmable gain, time gain compensation, and quantization conversion into a digital signal through an ultrasonic acquisition module;

[0031] The amplitude spectrum and nonlinear parameters of the received signals of each receiving channel are calculated, and the nonlinear parameters are compared with the relationship between the nonlinear parameters and the damage degree, and the relationship between the nonlinear parameters and the life of the target object material in the standard database to obtain the damage degree of the material to be tested and predict the life.

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

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

[0034]

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

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

[0037]

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

[0039]

[0040] Based on the same concept, the present invention further provides a readable storage medium, on which a processing program is stored. When the processing program is executed by a processor, any one of the above-mentioned detection methods is implemented.

[0041] Due to the adoption of the above technical solution, the present invention has the following advantages and positive effects compared with the prior art:

[0042] The nonlinear ultrasonic guided wave detection system based on multi-channel reception achieves an in-depth evaluation of the internal state of the material through efficient signal generation, flexible signal reception, precise signal processing and powerful data processing capabilities. This not only helps to timely discover potential micro-damage to the material, but also can predict the remaining life of the material, providing a scientific basis for maintenance and replacement, and significantly improving the reliability and practicality of the detection technology. Using the method of single-channel excitation and multi-channel simultaneous reception, the variable-angle receiving transducer array containing multiple array elements can simultaneously extract the time domain-frequency domain-space domain information of nonlinear harmonics at different positions of the material to be tested, thereby obtaining the degree of damage, spatial location of damage and life prediction of the material to be tested. A single acquisition can realize the extraction of nonlinear features at different positions, improve the efficiency of acquisition and reduce measurement errors. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0044] Figure 1 It is a structural diagram of a 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 A schematic diagram of a high-energy multi-period sinusoidal electrical signal modulated by a high-energy Hanning window of the present invention;

[0048] Figure 5 Cumulative effect curve and fitting result of the aluminum plate 1 material of the present invention;

[0049] Figure 6 Cumulative effect curve and fitting result of the aluminum plate 2 material of the present invention;

[0050] Figure 7 A variable-angle receiving transducer array is provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0051] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent 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, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

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

[0053] First embodiment

[0054] like Figure 1 As shown, a structural diagram of a nonlinear ultrasonic guided wave detection system based on multi-channel reception is shown, 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 is controlled by the trigger signal to generate an electrical signal and perform amplification and filtering processing;

[0056] The transmitting transducer is installed on the material to be tested through a wedge block, and generates ultrasonic waves to act on the target object under the stimulation of the high-energy fundamental frequency ultrasonic excitation module;

[0057] A variable angle receiving transducer array is installed on the material to be tested, and the angle is adjusted to match the ultrasonic guided wave excitation angle, so as 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 domain-frequency domain-space domain information of nonlinear harmonics at different positions of the material to be tested;

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

[0059] The control and signal processing module, which includes an FPGA chip and an ARM main processor, is used to generate control instructions and extract information in the time domain, frequency domain and space domain from the digital signal sent by the ultrasonic acquisition module, calculate the nonlinear parameters of the material carried by the guided wave signal, and perform micro-damage assessment and life prediction based on the nonlinear parameters of the material.

[0060] The nonlinear ultrasonic guided wave detection system based on multi-channel reception achieves an in-depth evaluation of the internal state of the material through efficient signal generation, flexible signal reception, precise signal processing and powerful data processing capabilities. This not only helps to timely discover potential micro-damage to the material, but also can predict the remaining life of the material, providing a scientific basis for maintenance and replacement, and significantly improving the reliability and practicality of the detection technology. Using the method of single-channel excitation and multi-channel simultaneous reception, the variable-angle receiving transducer array containing multiple array elements can simultaneously extract the time domain-frequency domain-space domain information of nonlinear harmonics at different positions of the material to be tested, thereby obtaining the degree of damage, spatial location of damage and life prediction of the material to be tested. A single acquisition can realize the extraction of nonlinear features at different positions, improve the efficiency of acquisition and reduce 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 is an arbitrary waveform generator connected to the ultrasonic acquisition module, and is used to generate a high-energy multi-cycle sinusoidal electrical signal modulated by a high-energy Hanning window based on the trigger signal and configuration instructions of the ultrasonic acquisition module and suppress the harmonic components therein. The linear power amplifier adopts a PMOS and NMOS tube push-pull output circuit with symmetrical and large current driving capabilities, and uses a diode unidirectional conduction circuit for isolation protection. The low-pass analog filter can effectively filter out the high-frequency interference components of 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, f is the center frequency of the sine wave, is the Hanning window envelope, and T is the total time length.

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

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

[0067] See also Figure 7The variable angle receiving transducer array includes a rectangular shell, a cylindrical wedge disposed inside the rectangular shell, a receiving transducer array fixed inside the cylindrical wedge, and a knob disposed on one end face of the cylindrical wedge, wherein 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 rectangular shell is provided with an arc track for the knob to move, and a coupling agent is filled between the rectangular shell and the cylindrical wedge. The preferred variable angle receiving transducer array can be adjusted within the range of 0°-45°, and can be matched with the ultrasonic guided wave excitation angle by adjustment, so that the ultrasonic guided wave generates fewer modes, which is conducive to the extraction of nonlinear harmonic signals. The variable angle enables the receiving transducer array to adapt to different measurement angles, and has a wider applicability compared to the traditional planar receiving transducer array.

[0068] Furthermore, the receiving transducer array includes multiple array elements, typically 64 array elements or 128 array elements, which are installed on the material to be tested, and are used to receive the ultrasonic guided wave signal fed back after the material to be tested by adjusting the angle to match the ultrasonic guided wave excitation angle, and convert it into a feedback electrical signal, thereby simultaneously extracting the time domain-frequency domain-space domain information of nonlinear harmonics at different positions of the material to be tested. The variable angle receiving transducer array can be controlled by any adjustment structure to adjust the angle, thereby realizing the extraction of the time domain-frequency domain-space domain information of nonlinear harmonics at different positions of the material to be tested.

[0069] See also Figure 2 In one embodiment, the ultrasonic 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 instruction of the control and signal processing module, it is used to amplify the feedback electrical signal first and then sample it and convert it into a digital signal. In one embodiment, the low noise amplifier adopts an operational amplifier with single-ended input and differential output, and the resistance value of the feedback resistor is controlled by programming to achieve three-level adjustment of the overall gain of 15dB, 18dB, and 21dB. The programmable attenuator achieves 0-36dB attenuation through a voltage divider network composed of a fixed resistor and a variable resistor. The input end of the programmable gain amplifier is connected to the programmable attenuator, and three-level adjustment of 21dB, 24dB, and 27dB can be achieved. Finally, the ultrasonic acquisition module can achieve a maximum gain of 48dB as a whole. Preferably, the gain of the low noise amplifier is set to 21dB, the gain of the programmable gain amplifier is set to 27dB, and the overall gain is 48dB. The relevant parameters such as the excitation frequency, number of cycles, center frequency of the transmission signal, and the delay of the ultrasonic receiving chip and the gain of each level are adjusted to achieve the target gain. 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 ultrasonic acquisition module is controlled by the instruction of the control and signal processing module to amplify and sample the feedback electrical signal, convert it into a digital signal and then output it for subsequent signal processing; see 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 module, wherein the analog front-end chip performs preliminary processing on the received signal, and 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 realize 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 space domain, obtain the material nonlinear parameters carried by the guided wave signal, and then perform micro-damage assessment and life prediction based on the nonlinear parameters of the material.

[0072] Specifically, a program is running in the ARM main processor, executing:

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

[0074] Based on the processed waveguide signal, the nonlinear parameters of the material carried by the waveguide signal are calculated, and the damage assessment results and life prediction of the material to be tested at different positions are obtained based on the nonlinear parameters.

[0075] The FPGA chip receives control instructions from the ARM main processor and controls the operation of the ultrasound acquisition module through the SPI bus and the IO port.

[0076] The process of the ARM main processor calculating and obtaining the material nonlinear parameters carried by the waveguide signal based on the processed waveguide signal specifically includes:

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

[0078]

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

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

[0081]

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

[0083]

[0084] According to the above derivation process, Figure 5 and Figure 6 The cumulative effect curves and fitting results of the two aluminum plate materials are shown, showing the normalized nonlinear parameters and change trends (i.e., cumulative effects) of the aluminum plates at different distances from the transmitting transducer probe. By comparing and analyzing the slopes of the cumulative effect fitting curves of the two aluminum plates, it can be judged 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, which extracts information from the ultrasonic acquisition signal in the time domain, frequency domain and space domain to obtain the nonlinear parameters of the material carried by the waveguide signal, and then performs micro-damage assessment and life prediction based on the nonlinear parameters of the material. The FPGA chip receives control instructions from the ARM main processor, controls the high-energy fundamental frequency ultrasonic excitation module and the ultrasonic acquisition module, and provides instructions such as timing logic, delay configuration, and gain setting. The detection of damage conditions at different positions of the material to be tested includes: performing fast Fourier transform on the restored waveguide signals measured in different channels to obtain an amplitude spectrum, and calculating the ratio of the harmonic amplitude to the square of the fundamental amplitude to obtain the nonlinear parameters of the material, and reflecting the damage conditions at different positions of the material to be tested according to the changes in the nonlinear parameters at different positions and comparing them with the standard database.

[0086] The power supply module is used to supply power to the above-mentioned module organization, and provides different digital voltages including driving the FPGA chip and the positive and negative symmetrical reference voltages required by the ultrasound acquisition module.

[0087] Preferably, an ultrasonic coupling agent is also provided between the transmitting transducer and the wedge, between the wedge and the material to be tested, and between the material to be tested and the variable angle receiving transducer array. There is no particular limitation on the material to be tested, which may be metal, composite material, bone plate, etc. In this embodiment, a square aluminum plate with a side length of 0.5 meters is selected as the material to be tested for the experiment, and the thickness is 1.5 mm.

[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] Controlled by a preset trigger signal, a high-energy multi-cycle sinusoidal electrical signal modulated by a Hanning window is generated, and an ultrasonic electrical signal is generated after linear power amplification, and the high-frequency components are filtered out to act 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 subjected to low-noise amplification, programmable attenuation, programmable gain, time gain compensation, and quantization conversion into a digital signal through an ultrasonic acquisition module;

[0093] The amplitude spectrum and nonlinear parameters of the received signals of each receiving channel are calculated, and the nonlinear parameters are compared with the relationship between the nonlinear parameters and the damage degree, and the relationship between the nonlinear parameters and the life of the target object material in the standard database to obtain the damage degree of the material to be tested and predict the life.

[0094] The high-energy multi-cycle sinusoidal electrical signal modulated by the Hanning window can effectively improve the penetration and detection depth of ultrasonic waves, effectively solve the problems of low energy and harmonic interference at the excitation end of traditional equipment, and improve the accuracy of nonlinear components in the results. Thereby improving the accuracy and reliability of detection. The variable angle receiving transducer array can realize all-round and multi-angle detection of the target object, improving the comprehensiveness and flexibility of detection. The low-noise amplification, programmable attenuation, programmable gain, time gain compensation and other functions of the ultrasonic acquisition module: these functions can improve the quality of the signal, reduce noise interference, and make the detection results more accurate and reliable. By calculating the amplitude spectrum and nonlinear parameters of the received signal of each receiving channel, the damage degree and life prediction of the material can be revealed, providing a basis for the maintenance and replacement of the material. Comparing the calculated nonlinear parameters with the relationship between the nonlinear parameters and the damage degree of the target object's material in the standard database and the relationship between the nonlinear parameters and the life can further improve the accuracy and reliability of the detection, providing a more scientific basis for the maintenance and replacement of the material.

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

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

[0097]

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

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

[0100]

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

[0102]

[0103] The process of evaluating micro-damage of the material to be tested is described here:

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

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

[0106] The 64-element variable-angle receiving transducer array receives the ultrasonic guided wave signal transmitted from the material to be tested 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 conversion on the electrical signal according to the instruction of the FPGA to convert it into the digital signal.

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

[0109] The ARM main processor performs digital filtering and other preprocessing on the received 64-channel signals, and then calculates the amplitude spectrum and nonlinear parameters of the received signals of each receiving channel, that is, the nonlinear parameters of different positions of the material to be tested. Then, the nonlinear parameters measured experimentally are compared with the relationship between the nonlinear parameters and the degree of damage of the material in the standard database, and the relationship between the nonlinear parameters and the life span, to obtain the degree of damage of the material to be tested, and to predict the life span.

[0110] Based on the same concept, the present invention also provides an electronic device, comprising: a memory, the memory being used to store a processing program; and a processor, the processor implementing any one of the above-mentioned nonlinear ultrasonic guided wave detection methods based on multi-channel reception when executing the processing program.

[0111] Based on the same concept, the present invention also provides a readable storage medium, on which a processing program is stored. When the processing program is executed by a processor, any one of the above-mentioned nonlinear ultrasonic guided wave detection methods based on multi-channel reception is implemented.

[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 is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of software. The computer software is stored in a storage medium, including several instructions to enable a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present disclosure. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk, etc., and other media that can store program codes.

[0113] Those skilled in the art can clearly understand that, for the sake of convenience and brevity in description, the identification content specifically executed by the above-described system and device can refer to the corresponding process in the aforementioned method embodiment.

[0114] The embodiments of the present invention are described in detail above in conjunction with 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 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 is controlled by the trigger signal to generate an electrical signal and perform amplification and filtering processing; A transmitting transducer, which generates ultrasonic waves to act on a target object under the stimulation of the high-energy fundamental frequency ultrasonic excitation module; A variable angle receiving transducer array, used for receiving the ultrasonic guided wave signal fed back by the target object and converting it into a feedback electrical signal; An ultrasonic acquisition module, under the instruction of the control and signal processing module, is used to first amplify the feedback electrical signal, then sample it and convert it into a digital signal; The control and signal processing module, which includes an FPGA chip and an ARM main processor, is used to generate control instructions and extract information in the time domain, frequency domain and space domain from the digital signal sent by the ultrasonic acquisition module, calculate the nonlinear parameters of the material carried by the guided wave signal, and perform micro-damage assessment and life prediction based on the nonlinear parameters of the material.

2. The nonlinear ultrasonic guided wave detection system based on multi-channel reception according to claim 1 is 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 performs power amplification processing on the high-energy multi-cycle sinusoidal electrical signal. The low-pass analog filter filters the amplified electrical signal to suppress the harmonic components therein.

3. The nonlinear ultrasonic guided wave detection system based on multi-channel reception according to claim 2 is characterized in that: The signal generator is controlled by the trigger signal to generate a high-energy multi-cycle sinusoidal electrical signal modulated by the Hanning window. The signal generator is generated in the following manner: Where A is the amplitude, f is the center frequency of the sine wave, 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 variable angle receiving transducer array comprises a rectangular shell, a cylindrical wedge arranged inside the rectangular shell, a receiving transducer array fixed inside the cylindrical wedge and a knob arranged 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 arranged on the end face of the cylindrical wedge, the rectangular shell is provided with an arc track for the knob to move, and a coupling agent is filled between the rectangular shell and the cylindrical wedge.

5. The nonlinear ultrasonic guided wave detection system based on multi-channel reception according to claim 1, characterized in that: The ultrasonic 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 have multiple adjustment levels respectively. The control and signal processing module adjusts the gain of the programmable attenuator and the programmable gain amplifier of the ultrasonic acquisition module.

6. The nonlinear ultrasonic guided wave detection system based on multi-channel reception according to claim 5, characterized in that: The ultrasonic acquisition module is controlled by the instructions of the control and signal processing module to first amplify and then sample the feedback electrical signal, convert it into a digital signal and then output 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 module, wherein the analog front-end chip performs preliminary processing on the received signal, and 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 realize variable gain amplification of the signal.

7. 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 signal sent by the ultrasonic acquisition module and calculates the amplitude spectrum and nonlinear parameters of the received signal of each receiving channel, further comprising: Solving the nonlinear wave equation yields the wave propagation formula at different locations: Among them, u is displacement, β is the second-order nonlinear parameter, w is frequency, k is wave number, and A is the fundamental amplitude; According to the formula of the second harmonic amplitude B: The calculated nonlinear parameter vector β is expressed as:

8. A nonlinear ultrasonic guided wave detection method based on multi-channel reception, characterized in that: The steps include: Controlled by a preset trigger signal, a high-energy multi-cycle sinusoidal electrical signal modulated by a Hanning window is generated, and an ultrasonic electrical signal is generated after linear power amplification, and the high-frequency components are filtered out to act on the target object; receiving the ultrasonic guided wave signal transmitted by the target object through a variable angle receiving transducer array and converting it into a feedback electrical signal; The feedback electrical signal is subjected to low-noise amplification, programmable attenuation, programmable gain, time gain compensation, and quantization conversion into a digital signal through an ultrasonic acquisition module; The amplitude spectrum and nonlinear parameters of the received signals of each receiving channel are calculated, and the nonlinear parameters are compared with the relationship between the nonlinear parameters and the damage degree, and the relationship between the nonlinear parameters and the life of the target object material in the standard database to obtain the damage degree of the material to be tested and predict the life.

9. The nonlinear ultrasonic guided wave detection method based on multi-channel reception according to claim 8, characterized in that: Calculating the amplitude spectrum and nonlinear parameters of the received signal of each receiving channel further includes: Solving the nonlinear wave equation yields the wave propagation formula at different locations: Among them, u is displacement, β is the second-order nonlinear parameter, w is frequency, k is wave number, and A is the fundamental amplitude; According to the formula of the second harmonic amplitude B: The calculated nonlinear parameter vector β is expressed as:

10. A readable storage medium, characterized in that: The readable storage medium stores a processing program, and when the processing program is executed by a processor, the detection method according to any one of claims 8 to 9 is implemented.

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