Nondestructive testing method and system and data processing method

Abstract

The invention discloses a nondestructive testing method and system and a data processing method, and relates to the technical field of nondestructive testing. Comprising the steps of obtaining initial detection data of a detected component; establishing at least one reference model according to the initial detection data, and obtaining simulation data corresponding to each reference model; determining target data according to the initial detection data and simulation data; and obtaining subsequent detection data, and comparing the subsequent detection data with the target data to form an evaluation result. According to the invention, high and low frequency mixed excitation signals are adopted, so that the penetrating power and resolution of detection are improved, surface defects and buried defects can be detected at the same time, and the comprehensiveness and accuracy of detection are remarkably enhanced; a picked complex response signal is decoupled by using an orthogonal phase locking method, a magnetic field signal and an electric field signal are effectively separated, the signal-to-noise ratio and the detection precision are improved, and accurate discrimination of defect types, depths and orientations is realized by establishing a reference model and acquiring analog data.

Description

Technical Field

[0001] The present invention relates to the technical field of nondestructive testing, and particularly to a nondestructive testing method, system and data processing method. Background Art

[0002] Currently, the main nondestructive testing means for gas turbine components include ultrasonic testing, magnetic particle testing, penetrant testing, eddy current testing and radiographic testing. Ultrasonic testing has high precision and can detect components with a relatively large thickness, but it is affected by echo interference, has high power consumption and low transducer efficiency, has high requirements for the shape and surface conditions of the components, requires a coupling agent, and can only detect defects larger than the grain size; magnetic particle testing is simple to operate, has a low cost, and can detect complex curved surfaces, but it can only detect defects on the surface and near the surface of the components, with relatively low precision; eddy current testing is convenient to operate and has high sensitivity to defects using the disturbance of the current field, but due to the skin effect caused by high-frequency excitation, it can only be used for the detection of surface and subsurface defects. In addition, the eddy current testing results are easily affected by the change of the probe lift-off; penetrant testing has relatively high sensitivity, but it can only detect surface-opening defects of the components; radiographic testing has a high cost and there are safety problems. Summary of the Invention

[0003] In view of the problems existing in the prior art, the present invention is proposed.

[0004] Therefore, the problems to be solved by the present invention are how to achieve multi-angle defect discrimination of gas turbine components, how to identify surface defects and buried defects of gas turbine components, and how to improve the detection precision and sensitivity of micro-defects.

[0005] To solve the above technical problems, the present invention provides the following technical solutions:

[0006] In a first aspect, an embodiment of the present invention provides a nondestructive testing method, which includes obtaining initial detection data of a component to be tested;

[0007] Establishing at least one reference model according to the initial detection data, and obtaining simulation data corresponding to each reference model;

[0008] Determining target data according to the initial detection data and the simulation data; obtaining subsequent detection data, and comparing it with the target data to form an evaluation result.

[0009] As a preferred solution of the nondestructive testing method of the present invention, wherein: the obtaining of the initial detection data of the component to be tested includes applying a mixed excitation signal to the component to be tested and collecting a response signal; performing decoupling processing on the response signal to obtain the initial detection data.

[0010] As a preferred embodiment of the non-destructive testing method of the present invention, wherein: obtaining subsequent detection data and comparing it with the target data to form an evaluation result includes defect discrimination according to the evaluation result;

[0011] Compare the preset first threshold, second threshold, and third threshold with the evaluation result to determine the trigger of the detection action;

[0012] The detection actions include no action, adjusting detection parameters, and re-detecting.

[0013] As a preferred embodiment of the non-destructive testing method of the present invention, wherein: obtaining subsequent detection data includes re-applying a mixed excitation signal to the component under test and collecting a response signal after adjusting the detection parameters according to the target data;

[0014] Perform decoupling processing on the response signal to obtain the subsequent detection data;

[0015] The step of obtaining subsequent detection data is performed at least once after each execution of the action of adjusting the detection parameters.

[0016] As a preferred embodiment of the non-destructive testing method of the present invention, wherein: obtaining subsequent detection data includes selecting a standard specimen according to the target data and testing the standard specimen;

[0017] Perform decoupling processing on the test result to obtain the subsequent detection data;

[0018] The step of obtaining subsequent detection data is performed at least once after each execution of the action of adjusting the detection parameters.

[0019] As a preferred embodiment of the non-destructive testing method of the present invention, wherein: the mixed excitation signal is synthesized by superimposing multiple sine signals with different frequencies, and its superimposing formula is:

[0020]

[0021] The total signal is:

[0022]

[0023] wherein, i is the number of frequencies, A i is the amplitude of the i-th frequency signal, f i is the frequency of the i-th frequency signal, is the phase of the i-th frequency signal.

[0024] As a preferred embodiment of the non-destructive testing method of the present invention, wherein: the decoupling processing uses an orthogonal phase-locked method, including the collected response signal: X(t) = A ssin(ωt + θ s ) is input into the quadrature lock-in amplifier;

[0025] Two orthogonal reference signals R i (t) = A ri sin(ωt) and R q (t) = A rq cos(ωt);

[0026] The I-channel signal and the Q-channel signal are output through the quadrature lock-in amplifier;

[0027] After passing through the low-pass filter, we get:

[0028]

[0029] Among them, X(t) is the picked-up response signal, A s is the amplitude of the signal, ω is the angular frequency of the signal, t is the time, θ s is the phase of the signal, R i (t) and R q (t) are two orthogonal reference signals, U i is the in-phase component after being processed by the quadrature lock-in amplifier and the low-pass filter, U q is the quadrature component after being processed by the quadrature lock-in amplifier and the low-pass filter.

[0030] In a second aspect, an embodiment of the present invention provides a non-destructive testing system, which includes a signal generator for generating a high-low frequency mixed excitation signal;

[0031] A probe (100), including a U-shaped ferrite skeleton (101), an excitation coil (102), and orthogonally arranged TMR Hall sensors (103);

[0032] A signal decoupling module, including a double quadrature lock-in amplifier for separating the high-low frequency mixed signal;

[0033] A signal processing module (104) for analyzing the characteristics of the decoupled magnetic field and electric field signals.

[0034] As a preferred solution of the non-destructive testing system according to the present invention, among them: a three-axis slide rail movement control platform for controlling the scanning movement of the probe relative to the component to be tested;

[0035] A signal acquisition module for converting the analog signal into a digital signal and transmitting it to a computer;

[0036] A display and storage module for displaying and storing the processed detection data.

[0037] Thirdly, an embodiment of the present invention provides a method for processing nondestructive testing data, which includes performing bi-orthogonal phase-locked decoupling on a high-low frequency mixed signal;

[0038] Extracting the I-channel of the magnetic field signal and the Q-channel of the electric field signal respectively;

[0039] Judging the defect type according to the waveform characteristics of the I-channel and Q-channel signals,

[0040] wherein, when the characteristic of the I-channel signal is a wave valley followed by a wave peak, it is determined that the magnetic field distortion is dominant;

[0041] when the characteristic of the Q-channel signal is a wave peak followed by a wave valley, it is determined that the electric field distortion is dominant;

[0042] Judging the depth and orientation of the defect according to the peak and valley values of the signal amplitude change curve. Description of the Drawings

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0044] Figure 1 It is a flowchart of the nondestructive testing method;

[0045] Figure 2 It is a signal synthesis diagram of the nondestructive testing method;

[0046] Figure 3 It is a principle block diagram of the orthogonal phase-locked decoupling signal of the nondestructive testing method.

[0047] Figure 4 It is a signal decoupling flowchart of the nondestructive testing method.

[0048] Figure 5 It is a schematic diagram of the orthogonal output signal of the nondestructive testing method.

[0049] Figure 6 It is a schematic diagram of eddy current testing of the nondestructive testing method.

[0050] Figure 7 It is a schematic diagram of high-low frequency electromagnetic testing of the nondestructive testing method.

[0051] Figure 8 It is a schematic diagram of the peak-to-peak signal comparison curve of the nondestructive testing method.

[0052] Figure 9 It is a schematic diagram of the scanning results of defect specimens at different angles of the nondestructive testing method.

[0053] Figure 10 Schematic diagram for the detection implementation of the non-destructive testing method

[0054] Figure 11 Overall flowchart of high and low frequency electromagnetic detection for the non-destructive testing method

[0055] Figure 12 Block diagram of the experimental system for the non-destructive testing system

[0056] Figure 13 Schematic diagram of the high and low frequency electromagnetic detection probe for the non-destructive testing system

[0057] Figure 14 Schematic diagram of the principle of eddy current testing for the non-destructive testing system

[0058] Figure 15 Schematic diagram of longitudinal defects for the non-destructive testing system

[0059] Figure 16 Schematic diagram of transverse defects for the non-destructive testing system

[0060] Figure 17 Experimental system diagram of high and low frequency electromagnetic detection for the non-destructive testing system Specific implementation manners

[0061] To make the above objects, features and advantages of the present invention more obvious and understandable, the following detailed description of the specific implementation manners of the present invention will be given with reference to the accompanying drawings of the specification

[0062] In the following description, many specific details are set forth to fully understand the present invention. However, the present invention can also be implemented in other ways different from this description. Those skilled in the art can make similar extensions without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below

[0063] Secondly, the so-called "one embodiment" or "embodiment" herein refers to a specific feature, structure or characteristic that can be included in at least one implementation manner of the present invention. The appearances of "in one embodiment" in different places in this specification do not all refer to the same embodiment, nor are they separate or selectively exclusive embodiments from other embodiments

[0064] Embodiment 1

[0065] Refer to Figure 1 , which is the first embodiment of the present invention. This embodiment provides a non-destructive testing method

[0066] including obtaining the initial detection data of the component to be tested

[0067] establishing at least one reference model based on the initial detection data and obtaining the simulation data corresponding to each reference model

[0068] Determine the target data based on the initial detection data and the simulation data; obtain the subsequent detection data and compare it with the target data to form an evaluation result.

[0069] In S1: Obtain the initial detection data of the component under test.

[0070] Specifically, apply a mixed excitation signal containing high-frequency and low-frequency components to the component under test and collect the response signal. Use a U-shaped ferrite as the excitation skeleton, and set an excitation coil above the skeleton. Arrange orthogonal TMR Hall sensors between the two legs of the U-shaped ferrite skeleton to pick up the magnetic field and electric field disturbance signals. Decouple the collected response signal to obtain the initial detection data.

[0071] In S2: Establish at least one reference model based on the initial detection data and obtain the simulation data corresponding to each reference model.

[0072] Specifically, based on the initial detection data, establish defect models of gas turbine components, such as surface crack models, internal hole models, etc. Use finite element analysis software to perform electromagnetic field simulations on these models to obtain simulation detection data under different defect types and degrees.

[0073] In S3: Determine the target data based on the initial detection data and the simulation data.

[0074] Specifically, compare and analyze the initial detection data and the simulation data, and extract characteristic parameters, such as signal amplitude, phase difference, etc. Through machine learning algorithms, such as support vector machine (SVM) or neural network, train a defect recognition model to obtain target data that can accurately distinguish the defect type and degree.

[0075] In S4: Obtain the subsequent detection data and compare it with the target data to form an evaluation result.

[0076] Specifically, in the actual detection process, repeat the steps of S1 to obtain the subsequent detection data. Input these data into the defect recognition model trained in S3 to obtain the prediction results of the defect type and degree. Compare the prediction results with the target data to evaluate the accuracy and reliability of the detection.

[0077] Among them, the component under test can be a turbine blade, turbine disk or compressor blade of a gas turbine, etc.; the initial detection data can include characteristics such as the amplitude, phase, and frequency response of the magnetic field signal and the electric field signal.

[0078] Specifically, when simulating surface cracks, a series of reference models can be established by changing the length, depth, and direction of the cracks. Using electromagnetic field simulation software, such as COMSOL Multiphysics, these models are simulated to obtain simulated detection data under different crack parameters.

[0079] Specifically, when simulating internal holes, multiple reference models can be established by changing the size, shape, and position of the holes. Using finite element analysis software, such as ANSYS, electromagnetic field analysis is performed on these models to obtain simulated detection data under different hole characteristics.

[0080] Furthermore, the subsequent detection data can be obtained by scanning the component to be measured. Using a three-axis slide rail movement control platform, the scanning movement of the probe relative to the component to be measured is controlled. By inputting movement control commands through the PC control software, the control platform is driven to perform uniform linear motion to achieve comprehensive detection of the component to be measured.

[0081] By adopting the high-low frequency hybrid excitation and orthogonal phase-locked decoupling technology in the embodiments of the present disclosure, the sensitivity and resolution of detection are improved. By establishing reference models and machine learning algorithms, the accuracy and reliability of defect identification are enhanced. This method can not only detect surface and internal defects simultaneously, but also provide quantitative information about the defects, providing strong support for the non-destructive testing and maintenance of gas turbine components, effectively reducing the equipment failure risk, and improving the operation safety.

[0082] Embodiment 2

[0083] Refer to Figures 2 - 11 , which is the second embodiment of the present invention. This embodiment provides a non-destructive testing method, including obtaining initial detection data of the component to be measured;

[0084] Establishing at least one reference model based on the initial detection data and obtaining simulation data corresponding to each reference model;

[0085] Determining target data based on the initial detection data and the simulation data; obtaining subsequent detection data and comparing it with the target data to form an evaluation result.

[0086] Further, obtaining the initial detection data of the component to be measured includes applying a hybrid excitation signal to the component to be measured and collecting the response signal; performing decoupling processing on the response signal to obtain the initial detection data.

[0087] Further, obtaining subsequent detection data and comparing it with the target data to form an evaluation result includes performing defect discrimination based on the evaluation result;

[0088] Comparing the preset first threshold, second threshold, and third threshold with the evaluation result to determine the triggering of the detection action;

[0089] The detection actions include no action, adjusting detection parameters, and re-detection.

[0090] Furthermore, obtaining subsequent detection data includes, after adjusting the detection parameters according to the target data, re-applying the mixed excitation signal to the component under test and collecting the response signal;

[0091] Performing decoupling processing on the response signal to obtain subsequent detection data;

[0092] The step of obtaining subsequent detection data is performed at least once after each execution of the action of adjusting the detection parameters.

[0093] Furthermore, obtaining subsequent detection data includes selecting a standard specimen according to the target data and detecting the standard specimen;

[0094] Performing decoupling processing on the detection result to obtain subsequent detection data;

[0095] The step of obtaining subsequent detection data is performed at least once after each execution of the action of adjusting the detection parameters.

[0096] Furthermore, the mixed excitation signal is synthesized by superimposing multiple sine signals with different frequencies, and its superimposing formula is:

[0097]

[0098] The total signal is:

[0099]

[0100] where i is the number of frequencies, A i is the amplitude of the i-th frequency signal, f i is the frequency of the i-th frequency signal, is the phase of the i-th frequency signal.

[0101] Preferably, sine signals with amplitudes of 10V and frequencies of 1kHz and 100Hz are synthesized, and the synthesized signal is as Figure 2 shown. When the high- and low-frequency signals are used for excitation, the expressions for the magnetic field situation and electric field situation on the surface of the specimen are as follows:

[0102]

[0103] where D is the electric displacement vector, B is the magnetic flux density, E is the electric field strength, H is the magnetic field strength; at the same time, the constitutive relations of the magnetic field and the conductor medium are introduced: D = εE; J = σE; B = μH; ε = ε0ε r ; μ = μ0μ r ;

[0104] Among them, σ is the conductivity with the unit of s / m, ε is the absolute permittivity, and ε r is the relative permittivity, and ε0 is the permittivity of vacuum with the unit of (F / m);

[0105] μ is the absolute permeability, and μ r is the relative permeability, μ0 = 4π×10 -7 is the permeability of vacuum with the unit of H / m.

[0106] Preferably, when there are defects on the surface of the specimen, it will cause distortions in both the orthogonal magnetic field and electric field. The picked-up distorted signal is a mixed signal of the two, and the signal expression is:

[0107] Y t (x, y, z) = E t (x, y, z) + B t (x, y, z)

[0108] Among them, Y t is the picked-up mixed signal; E t is the electric field signal; B t is the magnetic field signal.

[0109] Both the magnetic field leakage and electric field distortion caused by defects satisfy the Laplace equation and the boundary conditions when there are defects are as follows:

[0110]

[0111] Among them:

[0112]

[0113] c is the defect length, and δ is the skin depth.

[0114] Furthermore, the decoupling process adopts the quadrature lock-in method, including inputting the collected response signal: X(t) = A s sin(ωt + θ s ) into the quadrature lock-in amplifier;

[0115] Using two orthogonal reference signals R i (t) = A ri sin(ωt) and R q (t) = A rq cos(ωt);

[0116] Outputting the I-channel signal and Q-channel signal through the quadrature lock-in amplifier;

[0117] After passing through the low-pass filter, we get:

[0118]

[0119] Among them, X(t) is the picked-up response signal, A s is the amplitude of the signal, ω is the angular frequency of the signal, t is time, θ s is the phase of the signal, R i (t) and R q (t) are two orthogonal reference signals, U i is the in-phase component after being processed by an orthogonal phase-locked amplifier and a low-pass filter, U q is the quadrature component after being processed by an orthogonal phase-locked amplifier and a low-pass filter.

[0120] Preferably, using an orthogonal phase-locked amplifier can decouple the picked-up mixed voltage signal, realize the separation of the real and imaginary parts of the complex signal. The I-channel signal corresponds to the magnetic field signal, and the Q-channel signal corresponds to the electric field signal. By separating the signals, it is convenient to analyze the distortion information of the leakage magnetic field and the electric field, and then obtain the crack characteristic information at different angles.

[0121] Preferably, the input signal of the input channel is the voltage signal picked up by the detection coil, expressed as:

[0122] X(t) = A s sin(ωt + θ s )

[0123] The reference signal channel is two sine signals with the same frequency and a phase difference of 90°, expressed as:

[0124] R i (t) = A ri sin(ωt)

[0125] R q (t) = A rq cos(ωt)

[0126] After the two orthogonal input signals pass through the orthogonal phase-locked amplifier, two output signals can be obtained, namely the I-channel signal and the Q-channel signal, expressed as:

[0127]

[0128] Assume that the amplitudes of the two given reference signals are equal, that is, A rq = A ri = A r , after the two output signals pass through the low-pass filter, expressed as:

[0129] When a synthesized multi-frequency signal is used for excitation, the signal decoupling flow chart is as Figure 4 shown. By using a double orthogonal phase-locked amplifier to separate the high- and low-frequency mixed signals, signal decoupling is realized to obtain the defect information characteristic signal.

[0130] In summary, the non-destructive testing method and system provided by the present invention adopt a high-low frequency hybrid excitation signal, which improves the penetration ability and resolution of detection, can detect surface defects and buried defects simultaneously, and significantly enhances the comprehensiveness and accuracy of detection; by using the orthogonal phase-locked method to decouple the picked complex response signal, the magnetic field signal and the electric field signal are effectively separated, the signal-to-noise ratio and detection accuracy are improved, and multi-dimensional characteristic information is provided for defect discrimination; by establishing a reference model and obtaining simulation data, combined with machine learning algorithms, the accuracy and reliability of defect recognition are improved, and accurate discrimination of defect type, depth and orientation is realized; the present invention has made remarkable improvements in detection sensitivity, defect recognition accuracy and detection efficiency, provides strong support for the non-destructive testing and preventive maintenance of gas turbine components, effectively reduces the equipment failure risk, and improves the operation safety and economic benefits.

[0131] By adopting a U-shaped ferrite skeleton probe and orthogonally arranged TMR Hall sensors, the sensitivity of signal acquisition is improved, and the influence of external interference is reduced; through a three-axis slide rail movement control platform, a comprehensive scan of the component to be measured is realized, ensuring the integrity and representativeness of the detection results.

[0132] Embodiment 3

[0133] Refer to Figures 2 - 7 , which is the third embodiment of the present invention. This embodiment provides a non-destructive testing method. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through economic benefit calculation and simulation experiments.

[0134] 1. On the basis of Maxwell's theory equations, introduce a multi-frequency excitation signal to construct a multi-frequency defect signal theory;

[0135] 2. Use the orthogonal phase-locked method to decouple the picked complex signal, and use the characteristic signal to discriminate the defect;

[0136] 3. Build an experimental system for verification.

[0137] As Figure 5 , use the orthogonal phase-locked principle to decouple the signal, and the I-channel signal and Q-channel signal collected are shown in the figure. It can be seen from the figure that the two signals output by the high-low frequency electromagnetic detection system using the orthogonal phase-locked method principle have different amplitudes and phases. The I-channel signal is a magnetic field signal, and its characteristic is a wave valley first and then a wave peak; the Q-channel signal is an electric field signal, and its characteristic is a wave peak first and then a wave valley.

[0138] As Figures 6 - 7 , use high-low frequency electromagnetic detection probes and eddy current detection probes to scan specimens with different depths respectively. After denoising the picked voltage signals, as Figures 6 - 7As shown. It can be seen from the figure that when using the eddy current detection method for scanning, the signal fluctuates at defect depths of 4 mm and 5 mm, while the high and low frequency electromagnetic detection signals are overall stable. This is because the eddy current detection is strongly interfered by noise, and using the high and low frequency electromagnetic detection method can effectively improve the signal-to-noise ratio, thereby improving the accuracy and linearity of the detected defect signal.

[0139] As Figure 8 , in order to more intuitively analyze the response of the eddy current detection and high and low frequency electromagnetic detection methods to the defect depth, extract Figures 6 - 7 the peak-to-peak value of the voltage signal in Figure 8 as shown. Compared with the eddy current detection method, the high and low frequency electromagnetic detection method significantly increases the amplitude of the defect signal. Therefore, the high and low frequency electromagnetic detection method proposed in this patent can effectively improve the defect signal sensitivity compared with the traditional eddy current detection, achieving a better detection effect on buried defects.

[0140] As Figure 9 , when using the high and low frequency electromagnetic detection method to scan defect specimens at different angles, after denoising and smoothing the detected voltage signals obtained by scanning, it is shown as Figure 9 shown. It can be seen from the figure that for defect specimens with different surface angles, the high and low frequency electromagnetic detection method has a good detection effect. When the defect deflection angle θ = 0°, that is, the defect direction is the same as the probe scanning direction, the electric field is perpendicular to the defect direction. At this time, as a result of the electric field distortion, the voltage change curve shows a signal characteristic of first a peak and then a valley. When the defect deflection angle θ ∈ (0°, 30°), there is an angle between the defect direction and both the magnetic field and the electric field. At this time, it is the result of the combined distortion of the magnetic field and the electric field, but the electric field distortion dominates. The voltage change curve shows a signal characteristic of first a peak and then a valley, and the peak and valley values reach a maximum at θ = 0°. When the defect deflection angle θ = 30°, the signal deflects. At this time, the signal mainly changes from electric field distortion to magnetic field distortion. When the defect deflection angle θ ∈ (30°, 90°), it is still the result of the combined distortion of the magnetic field and the electric field, but the magnetic field distortion dominates. The voltage change curve shows a signal characteristic of first a valley and then a peak. When the defect deflection angle θ = 90°, that is, the defect direction is perpendicular to the probe scanning direction, the magnetic field magnetic induction line direction is perpendicular to the defect direction. At this time, as a result of the magnetic field distortion, the peak and valley values of the voltage change curve reach the maximum.

[0141] Example 4

[0142] Referring to Figures 12 - 17 , this is the fourth embodiment of the present invention. This embodiment provides a non-destructive testing system, including a signal generator for generating a high and low frequency mixed excitation signal;

[0143] Probe 100, including a U-shaped ferrite skeleton 101, an excitation coil 102, and a TMR Hall sensor 103 arranged orthogonally;

[0144] A signal decoupling module, including a biquadratic lock-in amplifier, is used to separate the high-frequency and low-frequency mixed signals.

[0145] A signal processing module 104 is used to analyze the characteristics of the decoupled magnetic field and electric field signals.

[0146] It should be noted that for the high-frequency and low-frequency electromagnetic detection method, a U-shaped ferrite 101 is used as the excitation skeleton, and a set of excitation coils 102 are arranged above the skeleton and connected to a high-frequency and low-frequency mixed excitation signal to realize the defect detection of the component to be tested. The principle is as follows: when the excitation coils 102 are connected to the high-frequency and low-frequency alternating current signals, due to the ferromagnetic properties of the ferrite, the alternating signal will generate an alternating magnetic field parallel to the two legs of the U-shaped ferrite 101 skeleton between the two legs, and the alternating magnetic field will generate an orthogonal alternating eddy current field. The orthogonal TMR Hall sensors 103 arranged between the two legs of the U-shaped ferrite 101 skeleton pick up the magnetic field disturbance and electric field disturbance signals generated by the surface defects of the specimen, decouple the sensor signals, and realize the detection and identification of the specimen defects. At the same time, due to the adoption of the high-frequency and low-frequency mixed excitation strategy, both the low-frequency electromagnetic signal can be used to improve the detection ability of buried defects, and the high-frequency electromagnetic signal can be used to improve the recognition accuracy of surface defects, with both the anti-interference ability of high-frequency signals and the strong penetration of low-frequency signals, enhancing the detection ability and resolution of surface defects and buried defects of the specimen.

[0147] Furthermore, a three-axis slide rail movement control platform is used to control the scanning movement of the probe relative to the component to be tested.

[0148] A signal acquisition module is used to convert the analog signal into a digital signal and transmit it to the computer.

[0149] A display and storage module is used to display and store the processed detection data.

[0150] Preferably, the high-frequency and low-frequency electromagnetic detection experimental system mainly includes a three-axis slide rail movement control platform, a multi-channel function signal generator, a multi-frequency electromagnetic probe, a signal processing module, a signal acquisition module, a PC and the specimen to be tested. The process of the multi-frequency alternating current electromagnetic detection experiment: fix the detection probe to the three-axis slide rail movement control platform through the platform clamping mechanism. After inputting the movement control command by the PC control software, drive the control platform to do a uniform linear motion. The moving distance and scanning speed are both input by the control software. Use the function signal generator to generate a current sine signal and connect it to the excitation coil of the detection probe for excitation. The induced signal of the detection coil is filtered and amplified by the signal processing module, and then the signal acquisition module converts the analog signal into a digital signal and transmits it to the computer to display and store the data.

[0151] Embodiment 5

[0152] Reference Figures 10 - 11 , which is the fifth embodiment of the present invention. This embodiment provides a method for processing nondestructive testing data, including

[0153] Performing bi - orthogonal phase - locked decoupling on the high - and low - frequency mixed signal:

[0154] Using a bi - orthogonal phase - locked amplifier to separate the collected high - and low - frequency mixed signal.

[0155] Specifically, input the collected response signal X(t)=A s sin(ωt + θ s ) into the quadrature phase - locked amplifier. Use two orthogonal reference signals R i (t)=A ri sin(ωt) and R q (t)=A rq cos(ωt). Output the I - channel signal and the Q - channel signal through the quadrature phase - locked amplifier. After passing through the low - pass filter, we get:

[0156]

[0157] Extract the magnetic - field signal on the I - channel and the electric - field signal on the Q - channel respectively:

[0158] The I - channel signal mainly corresponds to the magnetic - field signal, and the Q - channel signal mainly corresponds to the electric - field signal. Through digital signal processing techniques, such as Fourier transform or wavelet transform, further extract the characteristics of the I - channel and Q - channel signals, including amplitude, phase, frequency response, etc.

[0159] Discriminate the defect type according to the waveform characteristics of the I - channel and Q - channel signals:

[0160] Analyze the waveform characteristics of the I - channel and Q - channel signals to judge the defect type. The specific discrimination criteria are as follows:

[0161] When the characteristic of the I - channel signal is a wave - valley first and then a wave - peak, it is determined that the magnetic - field distortion is dominant;

[0162] When the characteristic of the Q - channel signal is a wave - peak first and then a wave - valley, it is determined that the electric - field distortion is dominant.

[0163] For example, the analysis of the detection results of specimens with surface defects at different angles:

[0164] When the defect deflection angle θ = 0°, the electric field is perpendicular to the defect direction. At this time, it is the result of electric - field distortion, and the voltage change curve shows the signal characteristic of a wave - peak first and then a wave - valley.

[0165] When the defect deflection angle θ = 45°, the defect direction has an angle with both the magnetic field and the electric field. At this time, it is the result of the combined distortion of the magnetic field and the electric field, but the electric - field distortion is dominant.

[0166] When the defect deflection angle θ = 90°, the direction of the magnetic field magnetic induction line is perpendicular to the defect trend. At this time, it is the result of magnetic field distortion, and the peak-to-valley value of the voltage change curve reaches the maximum value.

[0167] Judge the depth and orientation of the defect according to the peak-to-valley value of the signal amplitude change curve:

[0168] By analyzing the peak-to-valley values of the signal amplitude change curves of the I-channel and Q-channel signals, the depth and orientation of the defect can be further judged. The specific method is as follows:

[0169] The magnitude of the peak-to-valley value is positively correlated with the defect depth. The larger the peak-to-valley value, the greater the defect depth.

[0170] The position of the peak-to-valley value is related to the defect orientation, and the direction of the defect can be judged by the position where the peak-to-valley value appears.

[0171] For example, when using the high-low frequency electromagnetic detection method to scan specimens with different depths, the change of the signal amplitude with the defect depth can be observed. By extracting the peak-to-peak signal and drawing a comparison curve, it can be seen that the high-low frequency electromagnetic detection method significantly improves the amplitude of the defect signal compared with the traditional eddy current detection method, and achieves a better detection effect on buried defects.

[0172] In this embodiment, by performing refined processing and analysis on the high-low frequency mixed signal, accurate discrimination of the defect type, depth and orientation is achieved. This method can not only effectively distinguish surface defects and internal defects, but also provide quantitative information of the defects, greatly improving the accuracy and reliability of non-destructive testing.

[0173] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered by the scope of the claims of the present invention.

Claims

1. A non-destructive testing method, characterized in that: include, Obtaining initial test data of the tested component; Establishing at least one reference model according to the initial detection data, and acquiring simulation data corresponding to each reference model; Determine target data according to the initial detection data and the simulation data; Obtain subsequent detection data and compare it with the target data to form an evaluation result.

2. The nondestructive testing method according to claim 1, characterized in that: The obtaining of the initial detection data of the component under test includes applying a mixed excitation signal to the component under test and collecting a response signal; and performing decoupling processing on the response signal to obtain the initial detection data.

3. The nondestructive testing method according to claim 2, characterized in that: The obtaining of subsequent detection data and comparing it with the target data to form an evaluation result includes performing defect identification according to the evaluation result; Preset the first threshold, the second threshold and the third threshold to compare with the evaluation result to determine the triggering of the detection action; The detection actions include no action, adjusting detection parameters, and re-detection.

4. The nondestructive testing method according to claim 3, characterized in that: The obtaining of subsequent detection data includes adjusting the detection parameters according to the target data, reapplying the mixed excitation signal to the component under test and collecting the response signal; Performing decoupling processing on the response signal to obtain the subsequent detection data; The step of acquiring subsequent detection data is performed at least once after each execution of the action of adjusting the detection parameters.

5. The nondestructive testing method according to claim 4, characterized in that: The obtaining of subsequent test data includes selecting a standard sample according to the target data, and testing the standard sample; Decoupling the detection results to obtain the subsequent detection data; The step of acquiring subsequent detection data is performed at least once after each execution of the action of adjusting the detection parameters.

6. The nondestructive testing method according to claim 5, characterized in that: The mixed excitation signal is synthesized by superposition of multiple sinusoidal signals of different frequencies, and the superposition formula is: The total signal is: Among them, i is the number of frequencies, A i is the amplitude of the ith frequency signal, f i is the frequency of the i-th frequency signal, is the phase of the i-th frequency signal.

7. The nondestructive testing method according to claim 6, characterized in that: The decoupling process adopts an orthogonal phase-locking method, including converting the collected response signal: X(t) = A s sin(ωt+θ s ) is input to a quadrature lock-in amplifier; Use two orthogonal reference signals R i (t) = A ri sin(ωt) and R q (t) = A rq cos(ωt); Output I-channel signal and Q-channel signal through an orthogonal lock-in amplifier; After low-pass filtering, we get: Among them, X(t) is the picked-up response signal, A s is the amplitude of the signal, ω is the angular frequency of the signal, t is the time, θ s is the phase of the signal, R i (t) and R q (t) are two orthogonal reference signals, U i is the in-phase component after being processed by the orthogonal lock-in amplifier and low-pass filter, U q It is the orthogonal component after being processed by the orthogonal lock-in amplifier and low-pass filter.

8. A nondestructive testing system, based on the nondestructive testing method according to any one of claims 1 to 7, characterized in that: Also included is a signal generator for generating a high- and low-frequency mixed excitation signal; A probe (100) comprising a U-shaped ferrite skeleton (101), an excitation coil (102), and orthogonally arranged TMR Hall sensors (103); A signal decoupling module, including a dual orthogonal lock-in amplifier, is used to separate high- and low-frequency mixed signals; The signal processing module (104) is used to analyze the characteristics of the decoupled magnetic field and electric field signals.

9. The nondestructive testing method according to claim 6, characterized in that: Also included is a three-axis slide rail movement control platform for controlling the scanning movement of the probe relative to the component being tested; A signal acquisition module is used to convert analog signals into digital signals and transmit them to a computer; The display and storage module is used to display and store the processed detection data.

10. A non-destructive testing data processing method, based on the non-destructive testing method according to any one of claims 1 to 7, characterized in that: It also includes, performing dual orthogonal phase-locked decoupling of high and low frequency mixed signals; Extract the magnetic field signal I path and the electric field signal Q path respectively; Determine the defect type based on the waveform characteristics of the I and Q signals. Among them, when the signal characteristics of channel I are first a trough and then a peak, it is determined that the magnetic field distortion is dominant; When the Q-path signal features a peak followed by a trough, it is determined that the electric field distortion is dominant; The depth and orientation of the defect are determined based on the peak and valley values ​​of the signal amplitude change curve.

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