阅读说明：本技术 一种旋转电磁场非铁磁性材料裂纹尺寸测量方法 (Rotating electromagnetic field non-ferromagnetic material crack size measurement method ) 是由 李伟 赵建明 袁新安 李肖 赵建超 丁建喜 唐鑫 于 2021-04-09 设计创作，主要内容包括：本发明提供一种旋转电磁场非铁磁性材料裂纹尺寸测量方法,利用旋转电磁场阵列检测探头对非铁磁性材料被测区域进行扫查,获得Bx、By和Bz,首先计算出Bz信号2个峰值点之间的距离和角度,根据角度计算出平行于裂纹方向的磁场B,进而计算出磁场B的最大畸变率,利用已经训练好的人工神经网络计算出裂纹的长度和深度。本发明解决了目前旋转电磁场只采用Bz信号测量裂纹的尺寸,对不同方向的裂纹尺寸测量误差较大的难题,实现了不同方向裂纹尺寸的精准测量,为结构的安全评估提供了可靠的数据支撑,促进了旋转电磁场的推广应用。(The invention provides a method for measuring the size of a crack of a non-ferromagnetic material By using a rotating electromagnetic field array detection probe, which is used for scanning a detected area of the non-ferromagnetic material to obtain Bx, By and Bz. The invention solves the problem that the size of the crack is measured only by adopting Bz signals in the prior rotating electromagnetic field, so that the measurement error of the sizes of the cracks in different directions is larger, realizes the accurate measurement of the sizes of the cracks in different directions, provides reliable data support for the safety evaluation of the structure, and promotes the popularization and application of the rotating electromagnetic field.)

1. The invention provides a rotating electromagnetic field non-ferromagnetic material crack size measuring method which is characterized by comprising the following steps:

taking two peak points Bz of the Bz matrix_abAnd Bz_cdCalculating the distance Dx in the X direction between two peak points as (d-b) multiplied by L and the distance Dy in the Y direction as (c-a) multiplied by K, wherein L is the step length in the X direction when the detection probe scans, and K is the distance between two sensors;

the method also comprises the following third step:

calculating the distance between two peak pointsAnd an angle θ to the X direction is arctan (Dy/Dx);

the method also comprises the following four steps:

calculating a magnetic field matrix B ═ Bx × cos (θ × pi/180) + By × sin (θ × pi/180) parallel to the crack direction;

further comprises the following steps:

the distortion rate Δ B of the B magnetic field caused by the crack was calculated (B)_max-B₀)/B₀X 100% where B_maxIs the maximum distortion value of the B magnetic field, B₀The value of the magnetic field is the value of the magnetic field without the defect location.

2. The rotating electromagnetic field non-ferromagnetic material crack size measuring method according to claim 1, comprising the steps of:

scanning a non-ferromagnetic material detected area by utilizing a rotating electromagnetic field array detection probe, wherein the scanning direction of the probe is an X direction, the direction which is vertical to the X direction and is parallel to the surface of the detected area is a Y direction, the direction which is vertical to the surface of the detected area is a Z direction, and magnetic field matrixes in 3 directions obtained by a triaxial magnetic field sensor are respectively as follows:

3. the rotating electromagnetic field non-ferromagnetic material crack size measuring method according to claim 1, comprising six steps of:

inputting D and delta B into a pre-trained artificial neural network, and calculating the length and the depth of the crack, wherein the training data of the artificial neural network are as follows: and scanning a plurality of groups of cracks with different lengths and different depths along the X direction by using a rotating electromagnetic field probe, wherein the directions of the cracks are along the X direction, so that the distance between two corresponding Bz peak points and the distortion rate of the Bx are obtained, the input of the artificial neural network during training is the distance between the two Bz peak points and the distortion rate of the Bx, and the output is the length and the depth of the crack.

Technical Field

The invention relates to the field of nondestructive detection signal processing, in particular to a rotating electromagnetic field non-ferromagnetic material crack size measuring method.

Background

The alternating current electromagnetic field detection technology is a novel electromagnetic nondestructive detection technology, has the advantages of non-contact measurement, high quantization precision, insensitivity to lift-off and jitter, wide application occasions and the like, and is widely applied to detection of non-ferromagnetic materials such as nuclear power, aerospace and the like at present.

However, the conventional alternating current electromagnetic field detection technology has directionality, that is, a probe only has high detection sensitivity on cracks perpendicular to the direction of an induced electric field and has low detection sensitivity on other cracks, even leakage detection may occur, and the reliability and the detection efficiency of the alternating current electromagnetic field detection technology are greatly reduced due to the problems. Aiming at the defects of the conventional alternating current electromagnetic field detection technology, the rotating electromagnetic field technology induces a rotating electric field on the surface of a workpiece by means of orthogonal excitation, and on the basis of keeping the advantages of the alternating current electromagnetic field detection technology, the high sensitivity to cracks in all directions is ensured. However, in the existing rotating electromagnetic field detection technology, only Bz signals are used for inverting the size information of cracks, so that the measurement errors of the sizes of the cracks in different directions are large, the safety assessment of a detected structure is influenced, and great troubles are brought to the popularization and application of the rotating electromagnetic field detection technology.

Disclosure of Invention

The invention aims to provide a rotating electromagnetic field non-ferromagnetic material crack size measuring method, which realizes accurate measurement of the rotating electromagnetic field crack size, provides effective data support for structural safety evaluation, and is beneficial to popularization and application of a rotating electromagnetic field detection technology.

The invention provides a rotating electromagnetic field non-ferromagnetic material crack size measuring method, which comprises the following steps:

scanning a non-ferromagnetic material detected area by using a rotating electromagnetic field array detection probe, wherein the scanning direction of the probe is an X direction, the direction which is vertical to the X direction and is parallel to the surface of the detected area is a Y direction, the direction which is vertical to the surface of the detected area is a Z direction, and magnetic field matrixes in 3 directions obtained by a triaxial magnetic field sensor are respectively as follows:

step two, two peak points Bz of the Bz matrix are taken_abAnd Bz_cdCalculating the distance Dx in the X direction between two peak points as (d-b) multiplied by L and the distance Dy in the Y direction as (c-a) multiplied by K, wherein L is the step length in the X direction when the detection probe scans, and K is the distance between two sensors;

step three, calculating the distance between two peak pointsAn angle θ with the X direction is arctan (Dy/Dx);

step four, calculating a magnetic field matrix B parallel to the crack direction, namely Bx × cos (theta × pi/180) + By × sin (theta × pi/180);

step five, calculating the distortion rate Delta B of the B magnetic field caused by the crack (B)_max-B₀)/B₀X 100% where B_maxIs the maximum distortion value of the B magnetic field, B₀The value of the magnetic field at the defect-free position;

step six, inputting D and delta B into a pre-trained artificial neural network, and calculating the length and the depth of the crack, wherein the training data of the artificial neural network are as follows: and scanning a plurality of groups of cracks with different lengths and different depths along the X direction by using a rotating electromagnetic field probe, wherein the directions of the cracks are along the X direction, so that the distance between two corresponding Bz peak points and the distortion rate of the Bx are obtained, the input of the artificial neural network during training is the distance between the two Bz peak points and the distortion rate of the Bx, and the output is the length and the depth of the crack.

The invention provides a method for measuring the size of a crack of a non-ferromagnetic material By using a rotating electromagnetic field, which comprises the steps of scanning a detected region of the non-ferromagnetic material By using a rotating electromagnetic field array detection probe to obtain Bx, By and Bz, firstly calculating the distance and the angle between two peak points of a Bz signal, calculating the magnetic field B parallel to the crack direction according to the angle, further calculating the maximum distortion rate of the magnetic field B, further utilizes the trained artificial neural network to calculate the length and the depth of the crack, solves the problem that the prior rotating electromagnetic field only adopts Bz signals to invert the size information of the crack, the method has the advantages that the measurement accuracy of the sizes of the cracks in different directions is improved, the accurate measurement of the cracks in different directions is realized, reliable data support is provided for the safety assessment of the structure, and the popularization and application of the rotating electromagnetic field are promoted.

Drawings

FIG. 1 is a flow chart of crack size measurement of non-ferromagnetic material in the embodiment of the present application

FIG. 2 is an image drawn by a Bx matrix in the embodiment of the present application

FIG. 3 is an image drawn By the By matrix in the embodiment of the present application

FIG. 4 is an image drawn by Bz matrix in the embodiment of the present application

FIG. 5 is a B matrix rendered image in an embodiment of the present application

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the present invention is further described in detail with reference to the accompanying drawings and specific embodiments, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. Other embodiments, which can be derived by those skilled in the art from the embodiments of the present invention without inventive step, are within the scope of the present invention.

The invention provides a rotating electromagnetic field non-ferromagnetic material crack size measuring method, which comprises the following steps:

scanning a non-ferromagnetic material detected area by using a rotating electromagnetic field array detection probe, wherein the scanning direction of the probe is an X direction, the direction which is vertical to the X direction and is parallel to the surface of the detected area is a Y direction, the direction which is vertical to the surface of the detected area is a Z direction, and magnetic field matrixes in 3 directions obtained by a triaxial magnetic field sensor are respectively as follows:

images drawn By Bx, By, Bz are shown in fig. 2, 3, 4;

step two, two peak points Bz of the Bz matrix are taken_22-26And Bz_39-56When the detection probe scans, the step length L in the X direction is 0.25mm, the distance K between the two sensors is 0.25mm, and the distance (39-22) multiplied by 0.25 in the X direction between the two peak points is calculated to be 4.25mm, and the distance (56-26) multiplied by 0.25 in the Y direction is calculated to be 7.5 mm;

step three, calculating the distance between two peak pointsThe angle θ to the X direction is 29.54 ° (4.25/7.5);

step four, calculating a magnetic field matrix parallel to the crack direction: b ═ Bx × cos (29.54 × pi/180) + By × sin (29.54 × pi/180), and an image drawn By B is shown in fig. 5;

step five, calculating the distortion rate delta B of the B magnetic field caused by the crack, wherein the distortion rate delta B is (2.06-1.27)/1.27 multiplied by 100 percent is 62.2 percent, wherein 2.06 is the maximum distortion value of the B magnetic field, and 1.27 is the magnetic field value without the defect position;

step six, inputting 8.6 and 0.622 into a pre-trained artificial neural network, calculating the length of the crack to be 9.8mm and the depth to be 5.8mm, and respectively calculating the errors to be 2% and 3%, wherein compared with a conventional crack measuring method, the method has the advantage that the calculation result is more accurate; the training data of the artificial neural network is as follows: and scanning a plurality of groups of cracks with different lengths and different depths along the X direction by using a rotating electromagnetic field probe, wherein the directions of the cracks are along the X direction, so that the distance between two corresponding Bz peak points and the distortion rate of the Bx are obtained, the input of the artificial neural network during training is the distance between the two Bz peak points and the distortion rate of the Bx, and the output is the length and the depth of the crack.

The above embodiments are provided to further explain the objects, technical solutions and advantages of the present invention in detail, it should be understood that the above embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalents, improvements, etc. made within the spirit and principle of the present invention should be included in the scope of the present invention.