Double-arm magnet yoke type elastic telescopic eddy current array sensor

Abstract

The invention discloses a double-arm magnet yoke type elastic telescopic eddy current array sensor, which comprises a double-arm magnet yoke, an exciting coil, a detection coil array and a spring array, the excitation coil wound on the double-arm magnet yoke is connected with an excitation signal source, the detection coil array is connected with an acquisition module, and then the whole sensor is arranged on a tested piece; the excitation signal source generates an excitation signal and sends the excitation signal to the excitation coil, the excitation coil generates a primary magnetic field under the driving of the excitation signal, the primary magnetic field acts on a tested piece to generate induced eddy current, and the induced eddy current generates an induced magnetic field, namely a secondary magnetic field; the detection coil array is located in a superposed magnetic field of the primary magnetic field and the secondary magnetic field, signals of the superposed magnetic field are input to the acquisition module through the wiring terminal, and finally acquired detection signals are obtained through computer processing.

Description

Technical Field

[0001] The invention belongs to the technical field of nondestructive testing, and more specifically, relates to a double-arm magnetic yoke type elastic telescopic eddy current array sensor. Background Art

[0002] As a non-contact, high-precision sensor, eddy current sensor is widely used in defect detection of metal materials and is one of the most important detection methods in non-destructive testing. Traditional eddy current sensors are based on the principle of electromagnetic induction. They generate alternating magnetic fields through coils to stimulate metal objects to generate eddy currents, and then measure the changes in the reverse magnetic field generated by the eddy currents to infer whether the metal object has defects. However, the sensitivity, low detection efficiency and adaptability to the surface are the difficulties that limit its detection of tiny defects, especially cracks.

[0003] In response to the above problems, researchers proposed using a multi-sensor array for data fusion to improve the measurement accuracy and robustness of defects. However, the existing multi-sensor array design mainly relies on the specific arrangement of multi-channel sensor units in a plane, which limits its adaptability and measurement capabilities in complex environments, especially for the detection of complex surfaces of metal objects. In addition, the existing multi-sensor array still has problems such as insufficient sensitivity, limited measurement range, and inflexible sensor layout, which makes it difficult to detect tiny defects, especially crack defects on complex surfaces such as weld cracks. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a double-arm magnetic yoke elastic telescopic eddy current array sensor. Through the elastic telescopic design, the sensor array can flexibly adapt to the complex surface of metal objects, effectively improving the scope of application and reliability.

[0005] To achieve the above-mentioned purpose of the invention, the present invention provides a double-arm magnetic yoke type elastic telescopic eddy current array sensor, characterized in that it comprises: a double-arm magnetic yoke, an excitation coil, a detection coil array and a spring array;

[0006] The double-arm yoke is composed of a rectangular yoke and two support arms. The overall structure is in the shape of a "table". The structure of a single support arm is similar to a "U"-shaped beam. The cross-sectional height of the "U"-shaped beam is slightly larger than the rectangular surface of the yoke to fix the excitation coil.

[0007] The excitation coil is evenly wound on the rectangular yoke of the double-arm yoke, and the excitation coil is connected to an excitation signal source. When the excitation signal is input to the excitation coil, a uniform eddy current field can be generated on the tested object;

[0008] The detection coil array is located directly below the rectangular magnetic yoke, a spring is fixed on the top of each detection coil, and all the springs form a spring array;

[0009] When the double-arm magnetic yoke type elastic telescopic eddy current array sensor is working, the excitation coil wound on the double-arm magnetic yoke is connected to the excitation signal source, the detection coil array is connected to the acquisition module, and then the sensor is placed on the test piece as a whole;

[0010] The excitation signal source generates an excitation signal and sends it to the excitation coil. The excitation coil generates a primary magnetic field under the drive of the excitation signal. The primary magnetic field acts on the test piece to generate induced eddy currents, and the induced eddy currents generate an induced magnetic field, namely the secondary magnetic field. The detection coil array is in the superimposed magnetic field of the primary magnetic field and the secondary magnetic field, and the signal of the superimposed magnetic field is input into the acquisition module through the wiring terminal, and finally the collected detection signal is obtained through computer processing.

[0011] The object of the invention of the present invention is achieved in this way:

[0012] The invention discloses a double-arm magnetic yoke type elastic telescopic eddy current array sensor, comprising: a double-arm magnetic yoke, an excitation coil, a detection coil array and a spring array; the excitation coil wound on the double-arm magnetic yoke is connected to an excitation signal source, the detection coil array is connected to a collection module, and then the sensor is placed as a whole on a test piece; the excitation signal source generates an excitation signal and sends it to the excitation coil, the excitation coil generates a primary magnetic field under the drive of the excitation signal, the primary magnetic field acts on the test piece to generate induced eddy currents, and the induced eddy currents generate an induced magnetic field, i.e., a secondary magnetic field; the detection coil array is in a superimposed magnetic field of the primary magnetic field and the secondary magnetic field, and the signal of the superimposed magnetic field is input to the collection module through a wiring terminal, and finally the collected detection signal is obtained through computer processing.

[0013] At the same time, the double-arm magnetic yoke type elastic telescopic eddy current array sensor of the present invention also has the following beneficial effects:

[0014] (1) The present invention uses a unique double-arm magnetic yoke to create a regional uniform eddy current field, so that the signal changes sensed by the sensor array in the entire measured area are more consistent, thereby being able to more accurately identify local defects, and having stronger anti-interference ability and higher sensitivity;

[0015] (2) The present invention adopts an elastically retractable detection unit design, so that the sensor array can flexibly adapt to the complex surface of the metal object, making it closer to the surface of the specimen, reducing the lift-off effect, improving the detection capability of the complex surface of the specimen, and increasing the defect response and reliability of the sensor;

[0016] (3) The sensor array designed in the present invention has higher anti-interference ability and can provide stable signals in complex environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a structural diagram of a double-arm magnetic yoke type elastic telescopic eddy current array sensor of the present invention;

[0018] Figure 2 It is a structural diagram of the excitation part consisting of an excitation coil and a double-arm magnetic yoke;

[0019] Figure 3 It is a structural diagram of a detection array arranged in a 3*3 elastic retractable matrix;

[0020] Figure 4 It is a working schematic diagram of a double-arm magnetic yoke type elastic telescopic eddy current array sensor;

[0021] Figure 5 This is a physical picture of a double-arm magnetic yoke type elastic telescopic eddy current array sensor;

[0022] Figure 6 It is the uniform eddy current field distribution diagram generated by the sensor on the surface of the test piece;

[0023] Figure 7 It is the defect imaging diagram of defects with different widths and the detection signals corresponding to the sensors;

[0024] Figure 8 It is the defect imaging diagram of defects at different depths and the detection signals corresponding to the sensors;

[0025] Fig. 9 It is a defect imaging diagram of defects at different angles and the detection signal corresponding to the sensor. DETAILED DESCRIPTION

[0026] The specific implementation of the present invention is described below in conjunction with the accompanying drawings so that those skilled in the art can better understand the present invention. It should be noted that in the following description, when the detailed description of known functions and designs may dilute the main content of the present invention, these descriptions will be omitted here.

[0027] Example

[0028] In this embodiment, if Figure 1 As shown, the present invention is a double-arm magnetic yoke type elastic telescopic eddy current array sensor, comprising: a double-arm magnetic yoke, an excitation coil, a detection coil array and a spring array;

[0029] The double-arm yoke consists of a rectangular yoke and two support arms. The overall structure is in the shape of a "table". The structure of a single support arm is similar to a "U"-shaped beam. The cross-sectional height of the "U"-shaped beam is slightly larger than the rectangular surface of the yoke to fix the excitation coil.

[0030] The excitation coil is evenly wound on the rectangular yoke of the double-arm yoke. The excitation coil is connected to the excitation signal source. When the excitation signal is input to the excitation coil, a uniform eddy current field can be generated on the test piece, thereby improving the sensitivity and anti-interference performance of the array.

[0031] In this embodiment, the double-arm magnetic yoke is the magnetic path of the excitation field and also serves as the framework of the excitation coil. Figure 2 As shown, the excitation coil is wound around the connecting beam of the double-arm magnetic yoke to form the entire excitation part;

[0032] The detection coil array is located directly below the rectangular magnetic yoke. A spring is fixed on the top of each detection coil. All springs form a spring array. In this embodiment, Figure 3 As shown, a 3*3 array of detection coils and springs are used. 9 springs are placed on the 9 detection coils and combined with the corresponding detection coils to form a 3*3 elastic telescopic matrix detection array, which is placed directly below the excitation part; the 9 detection coils can move independently. Under the action of the spring force, the array detection coils can be pressed against the object to be measured, ensuring that the probe is lifted off at the minimum height, thereby adapting to different shapes of the measured surfaces. ;

[0033] When the double-arm magnetic yoke elastic telescopic eddy current array sensor is working, Figure 4 As shown, the excitation coil wound on the double-arm magnetic yoke is connected to the excitation signal source, the detection coil array is connected to the acquisition module, and then the sensor is placed on the test piece as a whole;

[0034] The excitation signal source generates an excitation signal and sends it to the excitation coil. The excitation coil generates a primary magnetic field under the drive of the excitation signal. The primary magnetic field acts on the test piece to generate induced eddy currents, and the induced eddy currents generate an induced magnetic field, namely the secondary magnetic field. The detection coil array is in the superimposed magnetic field of the primary magnetic field and the secondary magnetic field, and the signal of the superimposed magnetic field is input into the acquisition module through the wiring terminal, and finally the collected detection signal is obtained through computer processing.

[0035] Simulation Verification

[0036] In order to better illustrate the technical effect of the present invention, a specific embodiment is adopted to experimentally verify the present invention.

[0037] Figure 5 This is a physical picture of the double-arm magnetic yoke type elastic telescopic eddy current array sensor.

[0038] In this embodiment, if Figure 5 As shown, the parameters of each component of the double-arm magnetic yoke type elastic telescopic eddy current array sensor in this embodiment are as follows:

[0039] The double-arm yoke is made of ferrite material with high magnetic permeability, which can achieve a good role in guiding the magnetic circuit. The approximate size is 32*32*16 (unit: mm).

[0040] The excitation coil is wound with enameled copper wire, the diameter of the copper wire is 0.3 mm, and the number of turns is about 200. In this embodiment, the excitation signal is a sinusoidal signal with a frequency of 450 KHz.

[0041] The detection coil is made of enameled copper wire with a diameter of 0.1 mm and about 450 turns. It is connected with the spring to form a detection unit, and 9 detection units form a 3*3 matrix detection array.

[0042] Figure 6 It is the uniform eddy current field distribution diagram generated by the sensor on the surface of the test piece.

[0043] In this embodiment, if Figure 6 As shown, the arrow head indicates the flow direction of the eddy current, and the uniform eddy current is distributed directly below the detection array, thereby improving the signal consistency of the detection array.

[0044] Figure 7 It is a defect imaging diagram of defects of different widths and the detection signals corresponding to the sensors.

[0045] Figure 8 It is a defect imaging diagram of defects at different depths and the detection signals corresponding to the sensors.

[0046] Fig. 9 It is a defect imaging diagram of defects at different angles and the detection signal corresponding to the sensor.

[0047] In this embodiment, if Figure 7 , Figure 8 and Fig. 9 As shown, the sensor output changes significantly when it detects different defect sizes and different defect directions, and the sensitivity is relatively high, which is reflected in the image as brighter colors and a more intuitive view of the true shape of the defect. This indicates that the present invention has a certain detection capability for any form of near-surface defects.

[0048] Although the above describes the illustrative specific embodiments of the present invention to facilitate those skilled in the art to understand the present invention, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations using the concept of the present invention are protected.

Claims

1. A double-arm magnetic yoke type elastic telescopic eddy current array sensor, characterized in that: include: Double-arm magnetic yoke, excitation coil, detection coil array and spring array; The double-arm yoke is composed of a rectangular yoke and two support arms, and the overall structure is in the shape of a "table". The structure of a single support arm is similar to a "U"-shaped beam, and the cross-sectional height of the "U"-shaped beam is slightly larger than the rectangular surface of the yoke to fix the excitation coil; The excitation coil is evenly wound on the rectangular yoke of the double-arm yoke, and the excitation coil is connected to an excitation signal source. When the excitation signal is input to the excitation coil, a uniform eddy current field can be generated on the tested object; The detection coil array is located directly below the rectangular magnetic yoke, a spring is fixed on the top of each detection coil, and all the springs form a spring array; When the double-arm magnetic yoke type elastic telescopic eddy current array sensor is working, the excitation coil wound on the double-arm magnetic yoke is connected to the excitation signal source, the detection coil array is connected to the acquisition module, and then the sensor is placed on the test piece as a whole; The excitation signal source generates an excitation signal and sends it to the excitation coil. The excitation coil generates a primary magnetic field under the drive of the excitation signal. The primary magnetic field acts on the test piece to generate induced eddy currents, and the induced eddy currents generate an induced magnetic field, namely the secondary magnetic field. The detection coil array is in the superimposed magnetic field of the primary magnetic field and the secondary magnetic field, and the signal of the superimposed magnetic field is input into the acquisition module through the wiring terminal, and finally the collected detection signal is obtained through computer processing.

2. A double-arm magnetic yoke type elastic telescopic eddy current array sensor according to claim 1, characterized in that: The double-arm magnetic yoke and the excitation coil constitute the excitation part of the double-arm magnetic yoke type elastic telescopic eddy current array sensor.

3. A double-arm magnetic yoke type elastic telescopic eddy current array sensor according to claim 1, characterized in that: Each detection coil in the detection coil array can move independently, and the detection coil array is pressed against the tested object under the action of the spring force, ensuring that the lift-off height of the sensor is minimized, thereby adapting to tested surfaces of different shapes.

4. A double-arm magnetic yoke type elastic telescopic eddy current array sensor according to claim 1, characterized in that: The excitation coil and the detection coil are both wound with enameled copper wire; wherein, the diameter of the copper wire selected when winding the excitation coil is 0.3 mm, and the number of turns is 200 turns; the diameter of the copper wire selected when winding the detection coil is 0.1 mm, and the number of turns is 450 turns.

5. The double-arm magnetic yoke type elastic telescopic eddy current array sensor according to claim 1, characterized in that: The double-arm magnetic yoke is made of a ferrite material with high magnetic permeability, and the size of the double-arm magnetic yoke is preferably: length*width*height=32mm*32mm*16mm.

Images