阅读说明：本技术 一种双d聚焦线圈阵列远场涡流探头及其检测方法 (double-D focusing coil array far-field eddy current probe and detection method thereof ) 是由 宋凯 霍俊宏 李子璇 崔西明 张丽攀 于 2021-09-17 设计创作，主要内容包括：一种双D聚焦线圈阵列远场涡流探头及其检测方法。双D聚焦线圈阵列远场涡流探头包括用于产生聚焦激励磁场的激励单元、用于拾取检测信号的检测单元以及用于屏蔽直接耦合通道电磁场的屏蔽单元,所述激励单元包括呈一定角度倾斜的双D激励线圈和磁场结构。本发明的双D聚焦线圈阵列远场涡流探头,通过设置双D聚焦线圈使得磁场聚焦至铆接件,这样可以使得线圈产生的低频电磁场渗透至更深的深度,更加有利于检测较深的埋深缺陷；此外,通过设置阵列检测线圈呈线性阵列放置,这样可利用阵列检测信号对缺陷长度进行评价,从而避免重大事故的发生。此外,本发明还提供一种应用于双D聚焦线圈阵列远场涡流探头的检测方法。(A double-D focusing coil array far-field eddy current probe and a detection method thereof. The double-D focusing coil array far-field eddy current probe comprises an excitation unit for generating a focusing excitation magnetic field, a detection unit for picking up a detection signal and a shielding unit for shielding a direct coupling channel electromagnetic field, wherein the excitation unit comprises a double-D excitation coil and a magnetic field structure which are inclined at a certain angle. According to the double-D focusing coil array far-field eddy current probe, the double-D focusing coil is arranged to focus the magnetic field to the riveting piece, so that the low-frequency electromagnetic field generated by the coil can penetrate to a deeper depth, and the detection of a deeper buried depth defect is facilitated; in addition, the array detection coils are arranged in a linear array, so that the defect length can be evaluated by using array detection signals, and the occurrence of major accidents is avoided. In addition, the invention also provides a detection method applied to the double-D focusing coil array far-field eddy current probe.)

1. A double-D focusing coil array far-field eddy current probe is characterized in that: including the excitation unit that is used for producing focus excitation magnetic field, the detecting element that is used for picking up the detected signal and the shielding unit that is used for shielding direct coupling passageway electromagnetic field, the excitation unit is including being the two D excitation coils and the magnetic field structure of certain angle slope, the detecting element includes array detection coil group and array magnetic circuit structure, the shielding unit includes first shield, second shield and third shield, the shielding unit is multilayer shielding structure.

2. The dual-D focused coil array far-field eddy current probe of claim 1, wherein: the double-D exciting coil is two D-shaped winding coils, the double-D exciting coil is arranged in a certain angle along the axial line of the exciting unit and the detecting unit in a symmetrical mode and is wound in the same direction, the magnetic field structure is D-shaped, and the double-D exciting coil is wound in the magnetic field structure.

3. The dual-D focused coil array far-field eddy current probe of claim 2, wherein: the array detection coil group is a rectangular linear array coil group, the array magnetic circuit structure is a cuboid, and the array detection coil group is wound in the array magnetic circuit structure.

4. The dual-D focused coil array far-field eddy current probe of claim 3, wherein: the first shielding piece is wrapped on the double-D excitation coil and the magnetic field structure, the first shielding piece and the excitation unit are fixedly arranged on the third shielding piece, the second shielding piece is wrapped on the array detection coil group and the array magnetic circuit structure, and the second shielding piece and the detection unit are fixedly arranged on the third shielding piece.

5. The dual-D focused coil array far-field eddy current probe of claim 4, wherein: the first shielding piece and the second shielding piece are made of aluminum alloy materials, the third shielding piece is made of copper materials, and the magnetic field structure and the array magnetic structure are made of ferrite or silicon steel materials.

6. The dual-D focused coil array far-field eddy current probe of claim 5, wherein: the double D exciting coils are simultaneously communicated with sine exciting signals with the same phase and the same frequency, and the number of turns of the double D exciting coils is consistent.

7. The dual-D focused coil array far-field eddy current probe of claim 6, wherein: the excitation unit and the detection unit are placed across the rivet.

8. A dual-D focused coil array eddy current inspection method applied to the dual-D focused coil array far-field eddy current probe of claims 1-7, the method comprising the steps of:

the method comprises the following steps: the double-D focusing excitation coil arranged on the riveting structural part to be detected is communicated with a low-frequency sine wave signal with the same phase and the same frequency, and the double-D focusing excitation coil is arranged in the riveting structural part to be detected at a certain inclination angle to generate a focusing low-frequency magnetic field;

step two: the excitation unit and the detection unit are placed across the rivet, the double-D focusing array far-field eddy current detection probe is rotated along the surface of the rivet of the riveting piece, so that the array detection coil which is arranged at the hole edge and is in a linear array can pick up eddy current field signals containing internal defect information of the riveting piece to be detected in a far-field area, and the signals are sent to the signal conditioning module and the display module.

Technical Field

The invention relates to the technical field of airplane riveting structural member detection, in particular to a double-D focusing coil array far-field eddy current probe and a detection method thereof.

Background

The riveting structure is the main connection mode of aircraft structure assembly, and the aircraft is at the flight in-process, and the organism receives alternating stress's influence, thereby produces stress concentration around the riveting position hole and produces fatigue crack, leads to the organism fracture to cause the major accident. The existing eddy current detection technology has the advantages of no need of a coupling agent, high detection speed, high sensitivity, in-service detection and the like, so that the eddy current detection technology is widely applied to detection of riveting parts of airplanes, and particularly, a detection coil and an excitation coil are generally adopted to cross a far-field eddy current probe at the center of a rivet, so that the far-field eddy current probe can be used for rotatably detecting the crack defects around the hole of a riveting structure, but the far-field eddy current probe can only effectively detect the crack defects with shallow embedding depth, can not detect the hidden defects with deep embedding depth, and can not effectively evaluate the crack length, so that the riveting parts still have great potential safety hazards.

Disclosure of Invention

In order to solve the above technical problems, an object of the present invention is to provide a dual D-focus array far-field eddy current inspection probe and an inspection method thereof, which can effectively inspect defects deeper than the depth of burial in the prior art and can evaluate the length of crack defects.

In order to achieve the purpose, the invention provides the following technical scheme:

the utility model provides a two D focus coil array far field eddy current probe, is including the excitation unit that is used for producing focus excitation magnetic field, the detecting element that is used for picking up the detected signal and the shielding unit that is used for shielding direct coupling passageway electromagnetic field, the excitation unit is including being certain angle slope two D excitation coils and magnetic field structure, the detecting element is including array detection coil group and array magnetic circuit structure, the shielding unit includes first shield, second shield and third shield, the shielding unit is multilayer shielding structure.

Furthermore, the double-D exciting coil is two D-shaped winding coils, the double-D exciting coil is arranged in a certain angle along the axial line of the exciting unit and the detecting unit in a symmetrical mode and is wound in the same direction, the magnetic field structure is D-shaped, and the double-D exciting coil is wound in the magnetic field structure.

Furthermore, the array detection coil group is a rectangular linear array coil group, the array magnetic circuit structure is a cuboid, and the array detection coil group is wound in the array magnetic circuit structure.

Further, the first shielding member is wrapped on the double-D excitation coil and the magnetic field structure, the first shielding member and the excitation unit are both fixedly arranged on the third shielding member, the second shielding member is wrapped on the array detection coil set and the array magnetic circuit structure, and the second shielding member and the detection unit are both fixedly arranged on the third shielding member.

Furthermore, the first shielding piece and the second shielding piece are made of aluminum alloy materials, the third shielding piece is made of copper materials, and the magnetic field structure and the array magnetic circuit structure are made of ferrite or silicon steel materials.

Furthermore, the double-D exciting coils are simultaneously communicated with sine exciting signals with the same phase and the same frequency, and the number of turns of the double-D exciting coils is consistent.

Further, the excitation unit and the detection unit are placed across the rivet.

A dual-D focused coil array eddy current testing method applied to a dual-D focused coil array far-field eddy current probe as described above, the method comprising the steps of:

the method comprises the following steps: the double-D focusing excitation coil arranged on the riveting structural part to be detected is communicated with a low-frequency sine wave signal with the same phase and the same frequency, and the double-D focusing excitation coil is arranged in the riveting structural part to be detected at a certain inclination angle to generate a focusing low-frequency magnetic field;

step two: the excitation unit and the detection unit are placed across the rivet, the double-D focusing array far-field eddy current detection probe is rotated along the surface of the rivet of the riveting piece, so that the array detection coil which is arranged at the hole edge and is in a linear array can pick up eddy current field signals containing internal defect information of the riveting piece to be detected in a far-field area, and the signals are sent to the signal conditioning module and the display module.

The invention provides a double-D focusing coil array far-field eddy current probe, which comprises an excitation unit for generating a focusing excitation magnetic field, a detection unit for picking up a detection signal and a shielding unit for shielding a direct coupling channel electromagnetic field, wherein the excitation unit comprises a double-D excitation coil and a magnetic field structure which are inclined at a certain angle, the detection unit comprises an array detection coil group and an array magnetic circuit structure, and the shielding unit is of a multilayer shielding structure. According to the double-D focusing coil array far-field eddy current probe, the double-D focusing coil is arranged to focus the magnetic field to the riveting piece, so that the low-frequency electromagnetic field generated by the coil can penetrate to a deeper depth, and the detection of a deeper buried depth defect is facilitated; in addition, the array detection coils are arranged in a linear array, so that the defect length can be evaluated by using array detection signals, and the occurrence of major accidents is avoided.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it should be obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is an exploded view of a dual D focusing coil array far field eddy current probe of the present invention;

FIG. 2 is a schematic diagram of the placement of a dual D focusing coil array far field eddy current probe of the present invention;

FIG. 3 is a schematic diagram of the method for detecting far-field eddy currents of a dual-D focusing coil array according to the present invention.

The names corresponding to the reference numbers in the drawings are as follows:

the double-D excitation coil comprises a double-D excitation coil 1, a magnetic field structure 2, a first shielding member 3, an array detection coil group 4, an array magnetic circuit structure 5, a second shielding member 6, a third shielding member 7, a signal conditioning module 8 and a display module 9.

Detailed Description

The following is a preferred embodiment of the present invention, and it should be noted that it is obvious to those skilled in the art that various modifications and improvements can be made without departing from the principle of the present invention, and these modifications and improvements are also considered to be within the scope of the present invention.

Referring to fig. 1-3, a dual-D focusing coil array far-field eddy current probe according to the present invention includes an excitation unit for generating a focusing excitation magnetic field, a detection unit for picking up a detection signal, and a shielding unit for shielding a direct coupling channel electromagnetic field, where the excitation unit includes a dual-D excitation coil 1 and a magnetic field structure 2 inclined at a certain angle, the detection unit includes an array detection coil set 4 and an array magnetic circuit structure 5, the shielding unit includes a first shielding member 3, a second shielding member 6, and a third shielding member 7, and the shielding unit is a multi-layer shielding structure.

In one embodiment, the double-D excitation coils are two D-shaped winding coils, the double-D excitation coils are arranged in a certain angle along the axial line of the excitation unit and the detection unit, the two D-shaped winding coils are wound in the same direction, the magnetic field structure is D-shaped, and the double-D excitation coils are wound in the magnetic field structure.

In one embodiment, the array detection coil set is a rectangular linear array coil set, the array magnetic structure is a rectangular parallelepiped, and the array detection coil set is wound in the array magnetic structure.

In one embodiment, the first shielding member 3 is wrapped outside the dual-D excitation coil 1 and the magnetic field structure 2, the first shielding member 3 and the excitation unit are both fixed on the third shielding member 7, the second shielding member 6 is wrapped outside the array detection coil set 4 and the array magnetic circuit structure 5, and the second shielding member 6 and the detection unit are both fixed on the third shielding member 7.

In one embodiment, the first shield 3 and the second shield 6 are made of an aluminum alloy material, the third shield 7 is made of a copper material, and the magnetic field structure 2 and the array magnetic circuit structure 5 are made of a ferrite or silicon steel material.

In one embodiment, the double D excitation coils are simultaneously energized with sinusoidal excitation signals of the same phase and the same frequency, and the double D excitation coils have the same number of turns.

In one embodiment, the excitation unit and the detection unit are placed across the rivet.

The invention also provides a double-D focusing coil array eddy current testing method, which comprises the following steps: the double D-shaped coils are placed in the riveting component to be detected to generate a focusing low-frequency magnetic field; as shown in fig. 2, the excitation unit and the detection unit are placed across the rivet, and the dual D-focusing array far-field eddy current detection probe is rotated along the rivet surface of the rivet, so that the array detection coil 4 placed at the hole edge in a linear array picks up eddy current field signals containing internal defect information of the rivet to be detected in a far-field region, and sends the signals to the signal conditioning module 8 and the display module 9.

The double-D focusing coil array eddy current testing method further comprises defect length evaluation, and specifically comprises the following steps:

1) the detection signals of the array detection coil group are respectively recorded as

A₀、A₁、A₂……A_n(n=0,1,2,3……)；

2) The total width of the single detection coil is recorded as W, A_qn=A_n/A_n-1Let initial value n =1, and the threshold value be A_q0The following judgment is made:

A_qn≥A_q0 （1）

A_qn＜A_q0 （2）

if the formula (1) is established, performing a step 3); if the formula (2) is established, performing step 4);

3) so that n = n +1, in returning to step 2);

4) the crack length L can be determined by equation (3):

L=W×n （3）

the invention provides a double-D focusing coil array far-field eddy current probe, which comprises an excitation unit for generating a focusing excitation magnetic field, a detection unit for picking up a detection signal and a shielding unit for shielding a direct coupling channel electromagnetic field, wherein the excitation unit comprises a double-D excitation coil and a magnetic field structure which are inclined at a certain angle, the detection unit comprises an array detection coil group and an array magnetic circuit structure, and the shielding unit is of a multilayer shielding structure. According to the double-D focusing coil array far-field eddy current probe, the double-D focusing coil is arranged to focus the magnetic field to the riveting piece, so that the low-frequency electromagnetic field generated by the coil can penetrate to a deeper depth, and the detection of a deeper buried depth defect is facilitated; in addition, the array detection coils are arranged in a linear array, so that the defect length can be evaluated by using array detection signals, and the occurrence of major accidents is avoided.

The above examples only express the specific embodiments of the present invention, and the description thereof is more specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, various changes and modifications can be made without departing from the spirit of the present invention, and these changes and modifications are all within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.