A method and system for realizing nondestructive testing using magnetically responsive photonic crystals

Abstract

The present invention relates to the field of nondestructive testing technology, and in particular to a method and system for realizing nondestructive testing using magnetically responsive photonic crystals, the method comprising: magnetizing a test piece; encapsulating the magnetically responsive photonic crystals in a flexible plastic film to form a magnetically responsive photonic crystal sensor, and attaching the magnetically responsive photonic crystal sensor to the magnetized surface of the test piece; moving the magnetically responsive photonic crystal sensor to scan the surface of the test piece to determine whether the magnetically responsive photonic crystal sensor changes color, and if so, determining that there are defects on the surface of the test piece, and if not, determining that there are no defects on the surface of the test piece. Through this method and system, the problem of cleaning materials such as grease, paint, and rust on the surface that need to be removed in advance before testing can be effectively solved; the problem of easily causing surface contamination of materials during testing can also be solved; and the problem of easily causing environmental pollution by the liquid after cleaning can also be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of nondestructive testing, and in particular to a method and system for realizing nondestructive testing by utilizing magnetic response photonic crystals. Background Art

[0002] For ferromagnetic structural parts such as aircraft landing gear, aviation fasteners and connectors, the non-destructive testing method currently used is mainly traditional magnetic particle testing. For example, in the prior art, a Chinese invention patent with a publication number of CN104090022A and a publication date of October 8, 2014 is proposed. The technical solution disclosed in the patent is as follows: a composite magnetic detection device for universal standard parts, including a frame, a bolt detection workstation and a nut detection workstation, the bolt detection workstation and the nut detection workstation both include a sorting device, a composite magnetic flaw detection device and a spray system arranged on the frame, the sorting device cooperates with the composite magnetic flaw detection device, and the spray system cooperates with the composite magnetic flaw detection device so that the spray system can spray the magnetic suspension onto the standard parts during magnetic particle flaw detection, the bolt detection workstation also includes a clamping device and a conveying device supported by the frame, the conveying device is located below the composite magnetic flaw detection device, the sorting device and the composite magnetic flaw detection device respectively cooperate with the clamping device, so that the standard parts can be transferred from the sorting device to the composite magnetic flaw detection device.

[0003] In actual use, the above technical solution needs to dismantle and clean the structural parts before testing.

[0004] After the test is completed, the magnetic powder or magnetic suspension needs to be cleaned, which can easily cause contamination to the tested structural parts or liquid residue. Summary of the invention

[0005] In order to solve the above technical problems, the present invention proposes a method and system for realizing nondestructive testing using magnetically responsive photonic crystals, which can effectively solve the problem of removing grease, paint, rust and other materials on the surface before testing; it can also solve the problem of surface contamination of materials that is easily caused during testing; it can also solve the problem of environmental pollution caused by the liquid after cleaning.

[0006] The present invention is achieved by adopting the following technical solutions:

[0007] A method for realizing nondestructive testing using magnetically responsive photonic crystals comprises the following steps:

[0008] Step S 1 . Magnetize the test piece;

[0009] Step S 2 . Encapsulate the magnetically responsive photonic crystal in a flexible plastic film to make a magnetically responsive photonic crystal sensor, and attach the magnetically responsive photonic crystal sensor to the magnetized surface of the test piece;

[0010] Step S 3 . Move the magnetic response photonic crystal sensor to scan the surface of the test piece to determine whether the magnetic response photonic crystal sensor changes color. If so, it is determined that there are defects on the surface of the test piece. If not, it is determined that there are no defects on the surface of the test piece.

[0011] Also includes step S 4 , collect the discolored area on the surface of the magnetic response photonic crystal sensor, and identify the defect position and defect contour range through the position and area of ​​the discolored area.

[0012] Also includes step S 5 , by collecting the magnetic induction intensity of the color-changing area on the surface of the magnetic-responsive photonic crystal sensor, the size of the defect is quantitatively analyzed.

[0013] The step S 5 The specific steps include:

[0014] Step S 51 . Use the Hall sensor to collect the magnetic induction intensity on the surface of the test piece and calculate the induced voltage U:

[0015]

[0016] In the formula, is the sensitivity coefficient of the Hall sensor, is the control current of the input Hall sensor, is the magnetic field intensity of the excitation The angle between the normal vector of the Hall sensor;

[0017] Step S 52 . Determine the magnetic induction intensity of the leakage magnetic field at the defect on the test piece :

[0018]

[0019] In the formula, d is the opening width of the surface defect of the test piece, h is the depth of the defect on the test piece;

[0020] Step S 53 . Calculate the surface defects of the test piece separately Tangential component of the leakage magnetic field at point and the normal component :

[0021]

[0022]

[0023] Step S 54 . Move the Hall sensor so that it spans the width of the defect and collects the tangential signal amplitude during the entire movement process. And the normal signal amplitude :

[0024]

[0025]

[0026] Step S 55 . The tangential signal amplitude collected by the Hall sensor And the normal signal amplitude The defect size is quantitatively analyzed based on the changes in

[0027] A system for realizing nondestructive testing by using magnetically responsive photonic crystals, the system is applied to the above-mentioned nondestructive testing method, and comprises a magnetizing device and a testing device; the magnetizing device comprises an excitation source and a magnetic yoke, and an excitation coil is wound on the magnetic yoke; the testing device comprises a CCD image sensor and a magnetically responsive photonic crystal sensor made by encapsulating magnetically responsive photonic crystals in a flexible plastic film; the magnetically responsive photonic crystal sensor is used to scan the surface of a to-be-tested piece magnetized by the magnetizing device, and to record the color change area of ​​the magnetically responsive photonic crystal sensor by the CCD image sensor.

[0028] The detection device also includes a Hall sensor, which is used to collect the magnetic flux of the color-changing area on the surface of the magnetic-responsive photonic crystal sensor and generate a magnetic field signal waveform.

[0029] The detection device also includes a white light source, which is used to illuminate the magnetic-responsive photonic crystal sensor.

[0030] The excitation source includes a function generator and a power amplifier. The function generator is used to generate a low-frequency alternating current. The low-frequency alternating current is passed through the power amplifier to obtain a sinusoidal current that varies with time.

[0031] The magnetic response photonic crystal comprises magnetic colloid particles and a grease base, and the magnetic colloid particles comprise superparamagnetic colloid particles and ferromagnetic colloid particles.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] 1. In the present invention, a flexible magnetic response photonic crystal sensor is made by encapsulating a magnetic response photonic crystal material in a flexible plastic film. During detection, the flexible magnetic response photonic crystal sensor can be attached to a complex surface, which is easy to use. Moreover, since the magnetic response photonic crystal sensor is not affected by surface pollution, grease, paint, rust, etc. during detection, it can be used directly. For parts with coatings on the surface, the flexible magnetic response photonic crystal sensor can also be used without removing the coating. There is no need to spray materials or coupling agents on the surface of the object to be tested. Therefore, the present invention can greatly reduce the cleaning cost in the traditional magnetic powder detection process and solve the problem of magnetic suspension contamination. In addition, the same position can be tested repeatedly, and the magnetization state of each time will not affect the subsequent detection judgment. Therefore, if it is not necessary, the demagnetization process can be reduced, which greatly improves the detection efficiency.

[0034] 2. The present invention can also quantitatively analyze the size of defects by collecting the magnetic induction intensity of the discolored area on the surface of the magnetic response photonic crystal sensor, thereby improving the detection accuracy of defects.

[0035] 3. The detection system of the present invention is simple in composition and easy to use, and can integrate the magnetic response photonic crystal sensor and the CCD image sensor into a digital sensor, saving data during detection to facilitate subsequent offline analysis, thereby effectively improving the detection accuracy of defects.

[0036] 4. When magnetizing the test piece, the present invention uses a low-frequency AC excitation as the excitation source, that is, an AC excitation as low as one tenth of Hz, which can improve the shortcomings of DC excitation and high-frequency AC excitation, retain the low-noise characteristics of DC excitation, and introduce rich information of AC excitation to improve detection sensitivity and accuracy, while suppressing the influence of skin depth on detection.

[0037] 5. The magnetically responsive photonic crystals in the present invention can use superparamagnetic colloidal particles and ferromagnetic colloidal particles with strong magnetism, so that the color change phenomenon is more obvious when defects are detected. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, wherein:

[0039] Figure 1 It is a structural schematic diagram of the present invention;

[0040] Figure 2 It is a schematic diagram of testing the sensitivity of the magnetic response photonic crystal sensor to the magnetic field strength under different magnetic field strengths in the present invention;

[0041] Figure 3 A schematic diagram of the color change of the magnetic response photonic crystal sensor in the present invention;

[0042] Figure 4 Schematic diagram of the waveform of the tangential signal amplitude collected in the present invention;

[0043] Figure 5 Schematic diagram of the waveform of the normal signal amplitude collected in the present invention;

[0044] Markings in the figure:

[0045] 1. Excitation coil, 2. Magnetic yoke, 3. CCD image sensor, 4. Magnetic response photonic crystal sensor, 5. White light source, 6. Item to be tested. DETAILED DESCRIPTION

[0046] Example 1

[0047] As a basic embodiment of the present invention, the present invention includes a method for realizing nondestructive testing using magnetically responsive photonic crystals, comprising the following steps:

[0048] Step S 1 . Magnetize the test piece 6.

[0049] Step S 2 The magnetic response photonic crystal is encapsulated in a flexible plastic film to form a magnetic response photonic crystal sensor 4, and the magnetic response photonic crystal sensor 4 is attached to the magnetized surface of the test piece 6.

[0050] Step S 3 . Move the magnetic response photonic crystal sensor 4 to scan the surface of the test piece 6 to determine whether the magnetic response photonic crystal sensor 4 changes color. If so, it is determined that there is a defect on the surface of the test piece 6. If not, it is determined that there is no defect on the surface of the test piece 6. Specifically, when the test piece 6 is excited by the magnetic field, if there is a defect in the tested area, there is a leakage magnetic field at the defect, which causes the magnetic response photonic crystal sensor 4 to undergo magnetic assembly and produce a color change phenomenon. If there is no defect, the magnetic response photonic crystal sensor 4 does not respond.

[0051] Since the magnetic response photonic crystal sensor 4 is in the form of a flexible film, it is not affected by surface pollution, grease, paint, rust, etc. during detection and can be used directly. For parts with coatings on the surface, the magnetic response photonic crystal sensor 4 can also be used for detection without removing the coating, and does not need to spray materials or coupling agents on the surface of the test piece 6. Therefore, the present invention can greatly reduce the cleaning cost in the traditional magnetic powder detection process and solve the problem of magnetic suspension contamination.

[0052] Example 2

[0053] As a preferred embodiment of the present invention, the present invention includes a method for realizing nondestructive testing using magnetically responsive photonic crystals, comprising the following steps:

[0054] Step S 1 . Magnetizing the test piece 6 generally involves saturation magnetization of the test piece 6 . During saturation magnetization, the leakage magnetic field intensity and leakage magnetic flux at the defect of the test piece 6 will reach a maximum.

[0055] Step S 2 The magnetic response photonic crystal is encapsulated in a flexible plastic film to form a magnetic response photonic crystal sensor 4, and the magnetic response photonic crystal sensor 4 is attached to the magnetized surface of the test piece 6.

[0056] Step S 3 . Move the magnetic response photonic crystal sensor 4 to scan the surface of the test piece 6. If there is a defect, the change in the leakage magnetic field caused by the defect will cause the magnetic response photonic crystal sensor 4 to change color. Therefore, by judging whether the magnetic response photonic crystal sensor 4 changes color, it is judged whether there is a defect in the test area. If so, it is judged that there is a defect on the surface of the test piece 6. If not, it is judged that there is no defect on the surface of the test piece 6.

[0057] Step S 4 . Furthermore, the discolored area on the surface of the magnetically responsive photonic crystal sensor 4 can be collected and recorded by the CCD image sensor 3, and the data can be saved during detection to facilitate subsequent offline analysis, that is, the defect position and defect contour range can be identified through the position and area of ​​the discolored area.

[0058] Example 3

[0059] As another preferred embodiment of the present invention, the present invention includes a method for realizing nondestructive testing using magnetically responsive photonic crystals, comprising the following steps:

[0060] Step S 1 . Magnetize the test piece 6.

[0061] Step S 2 The magnetic response photonic crystal is encapsulated in a flexible plastic film to form a magnetic response photonic crystal sensor 4, and the magnetic response photonic crystal sensor 4 is attached to the surface of the magnetized test piece 6.

[0062] Step S 3 . Move the magnetic response photonic crystal sensor 4 to scan the surface of the test piece 6 to determine whether the magnetic response photonic crystal sensor 4 changes color. If so, it is determined that there are defects on the surface of the test piece 6. If not, it is determined that there are no defects on the surface of the test piece 6.

[0063] Step S 4 . By collecting the magnetic induction intensity of the discolored area on the surface of the magnetic response photonic crystal sensor 4, the size of the defect is quantitatively analyzed.

[0064] Example 4

[0065] As another preferred embodiment of the present invention, the present invention includes a system for realizing nondestructive testing using magnetically responsive photonic crystals, including a magnetizing device and a testing device. The magnetizing device includes an excitation source and a magnetic yoke 2, and an excitation coil 1 is wound on the magnetic yoke 2. The testing device includes a CCD image sensor 3 and a magnetically responsive photonic crystal sensor 4 made by encapsulating the magnetically responsive photonic crystal in a flexible plastic film.

[0066] The magnetization device is used to magnetize the test piece 6. Specifically, the conductive excitation coil 1 magnetizes the yoke 2, the yoke 2 magnetizes the test piece 6, and the defect leakage magnetic field of the test piece 6 magnetizes the magnetic response photonic crystal sensor 4. The magnetic response photonic crystal sensor 4 is used to scan the surface of the test piece 6 after being magnetized by the magnetization device. When the magnetic response photonic crystal sensor 4 is attached to the surface of the test piece 6 after magnetization, the change in the leakage magnetic field caused by the defect will cause the magnetic response photonic crystal sensor 4 to change color. The CCD image sensor 3 is used to record the color change area of ​​the magnetic response photonic crystal sensor 4, so as to facilitate the identification of the position and contour range of the defect.

[0067] Example 5

[0068] As the best embodiment of the present invention, the present invention includes a system for realizing nondestructive testing using magnetically responsive photonic crystals. Figure 1 , including a magnetization device and a detection device. The magnetization device includes an excitation source and a yoke 2. The yoke 2 can be a U-shaped pure iron yoke 2, and an excitation coil 1 is wound on the yoke 2 and placed on the back of the test piece 6. The excitation source includes a function generator and a power amplifier. In order to improve the shortcomings of DC excitation and high-frequency AC excitation, the excitation source adopts a low-frequency AC excitation method, that is, an AC excitation as low as one tenth of Hertz, which not only retains the low-noise characteristics of DC excitation, but also introduces rich information of AC excitation to improve detection sensitivity and accuracy, while suppressing the influence of skin depth on detection. The function generator can be a RIGOLDG4062 function waveform generator, and the power amplifier can be a N4LLPA05 power amplifier.

[0069] The low-frequency AC current is generated by a function generator, and a time-varying sinusoidal current is obtained after passing through a power amplifier. The U-shaped pure iron yoke 2 is wound through the excitation coil 1, and the low-frequency AC current is injected into the test piece 6. When the excitation source current is constant, the smaller the excitation frequency, the greater the normal magnetic induction intensity of the leakage magnetic field, which is not only conducive to enhancing the contrast between the defect and non-defect areas, but also improves the signal-to-noise ratio. Therefore, the AC current amplitude is set to 1A and the frequency is set to 0.2Hz.

[0070] The detection device includes a CCD image sensor 3, a Hall sensor, a white light source 5 and a magnetic response photonic crystal sensor 4. In this embodiment, the CCD image sensor 3 adopts an industrial camera VQ-310G-M120B0, the white light source 5 adopts a PHILIPS LED light source, and the Hall sensor adopts a TUNKIA TM5100 Gauss meter. The magnetic response photonic crystal sensor 4 is made by encapsulating a magnetic response photonic crystal in a flexible plastic film, and is in the form of a film. Among them, the magnetic response photonic crystal includes magnetic colloid particles and a grease base, and the magnetic colloid particles include superparamagnetic colloid particles and ferromagnetic colloid particles with strong magnetism. The magnetically induced assembly of magnetic colloid particles is driven by the forces between magnetic dipoles and between magnetic dipoles and external fields. When an external magnetic field is applied, the magnetic colloid particles are magnetized by the induced magnetic dipole moment. As the particle concentration increases and the magnetic force increases, the magnetic colloid particles will evolve from a one-dimensional chain structure to a two-dimensional and three-dimensional colloidal crystal. In addition, the magnetic interaction force can also cause a phase transition in the three-dimensional ordered structure, thereby changing the optical properties of the assembly. In a non-uniform external magnetic field, the force between the particles and the magnetic field drives the magnetic particles to migrate to the high magnetic field area, resulting in changes in the local particle concentration, which in turn causes changes in the optical properties of the assembly and produces a color change phenomenon.

[0071] In this embodiment, ferromagnetic colloidal particles are mixed with a grease base to form a magnetic fluid which is sealed in a flexible plastic film to form a magnetic response photonic crystal sensor 4. The sensitivity of the magnetic response photonic crystal sensor 4 to the magnetic field strength is tested under different magnetic field strengths, as shown in the attached manual. Figure 2 As shown, the stronger the magnetic field, the darker the color change of the magnetic response photonic crystal sensor 4. When the magnetic response photonic crystal sensor 4 is attached to the surface of the magnetized test piece 6, the leakage magnetic field change caused by the defect will cause the magnetic response photonic crystal sensor 4 to change color.

[0072] Based on the above system, the present invention also includes a method for realizing nondestructive testing using magnetically responsive photonic crystals, comprising the following steps:

[0073] Step S 1. Magnetize the test piece 6. The test piece 6 is made of aluminum alloy rods with nickel plating and passivation film layers on the surface. The electric spark grooving process is used to process five sizes with a width of 1mm and depths of 0.5, 1.0, 2.0, 3.0 and 4.0mm respectively. The yoke 2 is placed on the back of the test piece 6. After the excitation source passes a 1A, 0.2Hz current signal through the yoke 2, the test piece 6 is magnetized. Use a CCD image processor for detection with a frame rate of 120fps, and place the test piece 6 at the center of the field of view of the CCD image processor. The excitation intensity is generally selected to saturate the test piece 6. At saturation magnetization, the leakage magnetic field intensity and leakage magnetic induction intensity at the defect of the test piece 6 will reach the maximum.

[0074] Step S 2 The magnetic response photonic crystal is encapsulated in a flexible plastic film to form a magnetic response photonic crystal sensor 4, and the magnetic response photonic crystal sensor 4 is attached to the magnetized surface of the test piece 6. The conductive excitation coil 1 magnetizes the yoke 2, the yoke 2 magnetizes the test piece 6, and the defect leakage magnetic field of the test piece 6 magnetizes the magnetic response photonic crystal sensor 4.

[0075] Step S 3 . Move the magnetic response photonic crystal sensor 4 to scan the surface of the test piece 6, use the white light source 5 to illuminate the magnetic response photonic crystal sensor 4, and determine whether the magnetic response photonic crystal sensor 4 changes color. If so, it is determined that there are defects on the surface of the test piece 6. If not, it is determined that there are no defects on the surface of the test piece 6.

[0076] Step S 4 . Use CCD image sensor 3 to record the color change area on the surface of magnetic response photonic crystal sensor 4, as shown in the attached manual. Figure 3 As shown, the location and area of ​​the discolored area show the location of the defect and the scope of the defect outline.

[0077] Step S 5 By collecting the magnetic induction intensity of the discolored area on the surface of the magnetic response photonic crystal sensor 4, the size of the defect is quantitatively analyzed. More specifically, the following steps are included:

[0078] Step S 51 . Use the Hall sensor to collect the magnetic induction intensity on the surface of the test piece 6. When the Hall sensor has magnetic induction intensity in the direction I and current passes through in the direction I, the positive charge will be concentrated on one side of the Hall sensor due to the effect of the magnetic field force on the current in the magnetic field, and an induced voltage U will be generated:

[0079]

[0080] In the formula, is the sensitivity coefficient of the Hall sensor, is the control current of the Hall sensor input, is the magnetic field intensity of the excitation The angle between the Hall sensor and the normal vector.

[0081] Step S 52 Assuming that the surface magnetic charge density at the defect of the test piece 6 is constant, the width of the opening on the test piece 6 is d , the depth is h The defect, the magnetic induction intensity of the exciting magnetic field is , then the magnetic induction intensity of the leakage magnetic field at the defect on the test piece 6 is :

[0082]

[0083] Step S 53 . Adjust the probe angle of the Hall sensor so that the tangential component of the leakage magnetic field enters the probe of the Hall sensor vertically, and obtain the tangential component of the leakage magnetic field through the magnetic charge analysis method. Alternatively, the normal component of the leakage magnetic field is made to enter the probe of the Hall sensor vertically, and the normal component of the leakage magnetic field is obtained by the magnetic charge analysis method. .

[0084] Among them, the surface defects of the test piece 6 Tangential component of the leakage magnetic field at point and the normal component The calculation methods are:

[0085]

[0086]

[0087] Step S 54 . Move the Hall sensor so that it spans the width of the defect and collects the tangential signal amplitude during the entire movement process. And the normal signal amplitude :

[0088] Specifically, starting from the left side of the defect, move the Hall sensor so that it crosses the width of the defect (the short side of the defect size) and reaches the right side of the defect, and collects the tangential signal amplitude during the entire movement process. The results are as shown in the attached manual. Figure 4 Alternatively, starting from the left side of the defect, move the Hall sensor so that it spans the width of the defect (the short side of the defect size) and reaches the right side of the defect, and collect the tangential signal amplitude during the entire movement process. The results are as shown in the attached manual. Figure 5 shown.

[0089] Step S 55 For the color changing area of ​​the magnetic response photonic crystal sensor 4 attached to the test block, the amplitude of the tangential signal collected by the Hall sensor And the normal signal amplitude Quantitative analysis of defect size can be performed based on the change of Figure 4 It can be seen that even if the defect depth changes, that is, increases from 0.5mm to 4mm, from the attached manual Figure 4 As can be seen from the box in the figure, the wave width of the tangential signal amplitude can still show the width of the defect of 1mm. Figure 5 It can be seen that even if the defect depth changes, that is, increases from 0.5mm to 4mm, from the attached manual Figure 5 It can be seen from the box in the figure that the distance between the peak and the trough in the normal signal amplitude can still show the width of the defect is 1mm.

[0090] In summary, after reading the present invention document, ordinary technicians in this field can make various other corresponding transformation schemes based on the technical scheme and technical concept of the present invention without creative mental labor, which all fall within the scope of protection of the present invention.

Claims

1. A method for realizing nondestructive testing using magnetically responsive photonic crystals, characterized in that: The following steps are involved: Step S1. Magnetizing the test piece (6); Step S2. Encapsulating the magnetically responsive photonic crystal in a flexible plastic film to form a magnetically responsive photonic crystal sensor (4), and attaching the magnetically responsive photonic crystal sensor (4) to the magnetized surface of the test piece (6); Step S3. Move the magnetic response photonic crystal sensor (4) to scan the surface of the test piece (6) to determine whether the magnetic response photonic crystal sensor (4) changes color. If so, it is determined that there is a defect on the surface of the test piece (6). If not, it is determined that there is no defect on the surface of the test piece (6); Step S4. collecting the discolored area on the surface of the magnetic response photonic crystal sensor (4), and identifying the defect position and defect contour range through the position and area of ​​the discolored area; Step S5. By collecting the magnetic induction intensity of the discolored area on the surface of the magnetic response photonic crystal sensor (4), the size of the defect is quantitatively analyzed, which specifically includes the following steps: Step S 51 . Use the Hall sensor to collect the magnetic induction intensity on the surface of the test piece (6) and calculate the induced voltage U: In the formula, is the sensitivity coefficient of the Hall sensor, is the control current of the Hall sensor input, is the magnetic field intensity of the excitation The angle between the normal vector of the Hall sensor; Step S 52 . Determine the magnetic induction intensity of the leakage magnetic field at the defect on the test piece (6) : In the formula, d is the opening width of the surface defect of the test piece (6), h is the depth of the defect on the test piece (6); Step S 53 . Calculate the surface defects of the test piece (6) respectively Tangential component of the leakage magnetic field at point and the normal component : Step S 54 . Move the Hall sensor so that it spans the width of the defect and collects the tangential signal amplitude during the entire movement process. And the normal signal amplitude : Step S 55 . The tangential signal amplitude collected by the Hall sensor And the normal signal amplitude The defect size is quantitatively analyzed based on the changes in 2. A system for nondestructive testing using magnetically responsive photonic crystals, characterized in that: The system is applied to the non-destructive testing method in claim 1, comprising a magnetizing device and a testing device; the magnetizing device comprises an excitation source and a magnetic yoke (2), and the excitation coil (1) is wound on the magnetic yoke (2); the testing device comprises a CCD image sensor (3) and a magnetic responsive photonic crystal sensor (4) made by encapsulating a magnetic responsive photonic crystal in a flexible plastic film; the magnetic responsive photonic crystal sensor (4) is used to scan the surface of the test piece (6) after being magnetized by the magnetizing device, and record the color change area of ​​the magnetic responsive photonic crystal sensor (4) through the CCD image sensor (3).

3. A system for implementing nondestructive testing using magnetically responsive photonic crystals according to claim 2, characterized in that: The detection device also includes a Hall sensor, which is used to collect the magnetic induction intensity of the color change area on the surface of the magnetic response photonic crystal sensor (4) and generate a magnetic field signal waveform.

4. A system for implementing nondestructive testing using magnetically responsive photonic crystals according to claim 3, characterized in that: The detection device further comprises a white light source (5), wherein the white light source (5) is used to illuminate the magnetic response photonic crystal sensor (4).

5. The system for realizing nondestructive testing using magnetically responsive photonic crystals according to claim 2, characterized in that: The excitation source includes a function generator and a power amplifier. The function generator is used to generate a low-frequency alternating current. The low-frequency alternating current is passed through the power amplifier to obtain a sinusoidal current that varies with time.

6. The system for realizing nondestructive testing using magnetically responsive photonic crystals according to claim 2, characterized in that: The magnetic response photonic crystal comprises magnetic colloid particles and a grease base, and the magnetic colloid particles comprise superparamagnetic colloid particles and ferromagnetic colloid particles.

Images