Pipeline imaging method based on asymmetric ultrasonic guided wave mode
阅读说明：本技术 基于非对称超声导波模态的管道成像的方法 (Pipeline imaging method based on asymmetric ultrasonic guided wave mode ) 是由 方舟 黄宴委 于 2021-09-14 设计创作，主要内容包括：本发明提出一种基于非对称超声导波模态的管道成像的方法,其特征在于：在管道一端安装传感器,通过多次等角度A°地改变传感器在管道周向的位置以采集传感器在管道不同周向位置的信号,采集的信号数量等于360°/A°；通过所有采集的信号用以对整根管道成像；所述传感器包括柔性印刷线圈和磁致伸缩材料；所述磁致伸缩材料用于粘贴在管道上；所述柔性印刷线圈粘贴在磁致伸缩材料上,其周向覆盖范围是管道整个周向的一半。本发明可以通过对管道的成像确定管道中缺陷的周向位置与轴向位置。(The invention provides a pipeline imaging method based on an asymmetric ultrasonic guided wave mode, which is characterized by comprising the following steps: installing a sensor at one end of the pipeline, and changing the circumferential position of the sensor in the pipeline by a plurality of times of equal angles of A degrees to acquire signals of the sensor at different circumferential positions of the pipeline, wherein the number of the acquired signals is equal to 360 degrees/A degrees; imaging the whole pipeline by all the acquired signals; the sensor comprises a flexible printed coil and a magnetostrictive material; the magnetostrictive material is used for being stuck on a pipeline; the flexible printed coil is adhered to the magnetostrictive material, and the circumferential coverage range of the flexible printed coil is half of the whole circumferential range of the pipeline. The present invention can determine the circumferential and axial location of defects in a pipe by imaging the pipe.)
1. A method for pipeline imaging based on asymmetric ultrasonic guided wave mode is characterized in that: installing a sensor at one end of the pipeline, and changing the circumferential position of the sensor in the pipeline by a plurality of times of equal angles of A degrees to acquire signals of the sensor at different circumferential positions of the pipeline, wherein the number of the acquired signals is equal to 360 degrees/A degrees; imaging the whole pipeline by all the acquired signals; the sensor comprises a flexible printed coil and a magnetostrictive material; the magnetostrictive material is used for being stuck on a pipeline; the flexible printed coil is adhered to the magnetostrictive material, and the circumferential coverage range of the flexible printed coil is half of the whole circumferential range of the pipeline.
2. The method of asymmetric ultrasonic guided wave mode based pipe imaging according to claim 1, wherein: the wires on the flexible printed coil are connected with each other to form four rows of symmetrical two-to-two-circuit folding circuits which are alternately arranged.
3. The method of asymmetric ultrasonic guided wave mode based pipe imaging according to claim 1, wherein: the magnetostrictive material comprises 48.94% of iron, 48.75% of cobalt, 0.01% of carbon, 0.05% of silicon, 0.30% of niobium, 0.05% of manganese and 1.90% of vanadium.
4. The method of asymmetric ultrasonic guided wave mode based pipe imaging according to claim 2, wherein: the length of the flexible printing coil along the axial direction of the pipeline to be tested is 48mm, and the length along the circumferential direction of the pipeline to be tested is determined according to the diameter of the pipeline to be tested; 40 leads are arranged along the axial direction of the pipeline to be tested, and 39 leads are arranged along the circumferential direction of the pipeline to be tested; the line widths and the intervals of all the conducting wires are respectively 1mm and 0.2 mm; the conducting wires are connected with each other to form four sections of folding circuits, and the width of each section of folding circuit is 12 mm; the flexible printed coil is provided with two bonding pads which are respectively positioned at two ends of the folding circuit.
5. The method of asymmetric ultrasonic guided wave mode based pipe imaging according to claim 1, wherein: and simulating the circumferential distribution of longitudinal asymmetric ultrasonic guided wave modal energy and/or the circumferential distribution of torsional asymmetric ultrasonic guided wave modal energy through a computer program, and corresponding to the pipeline imaging to obtain the position of the defect.
6. The method for imaging a pipe according to any one of claims 1-5 based on an asymmetric ultrasonic guided wave mode, comprising the steps of:
step S1: adhering the magnetostrictive material to a pipeline, wherein the adhering range is the circumferential range of the whole pipeline;
step S2: magnetizing the magnetostrictive material with a permanent magnet;
step S3: adhering the flexible printed coil on a magnetostrictive material, wherein the adhering range is half of the whole circumferential range of the pipeline;
step S4: inputting a sine wave signal modulated by a Hanning window with 5 periods through a flexible printing coil by adopting a self-excitation self-receiving mode, and collecting a receiving signal;
step S5: rotating the circumferential position of the flexible printed coil on the pipeline at equal angles, and collectingNThe sub-signal(s) is (are),N≥8；
step S6: read the collectionNTime corresponding to defect echo in individual signaltBy usingV ∙ t /2 calculating the axial position of the defectL；
Step S7: according to the axial position of the defectLObtaining the axial position of the asymmetric ultrasonic guided wave mode by utilizing the relation between the amplitude obtained by modeling and the circumferential positionLAmplitude versus circumferential position.
7. The method of asymmetric ultrasonic guided wave mode based pipe imaging according to claim 6, wherein: further comprising:
step S8: recording the acquisitionNThe amplitude of the defect echo in the signal, which is plottedNA relation graph of the defect echo amplitude of each signal and the circumferential position;
step S9: corresponding the circumferential position of the maximum amplitude in the relational graph obtained in the step S8 to the circumferential position of the maximum amplitude in the relational graph obtained in the step S7, thereby determining other circumferential positions in the relational graph obtained in the step S8; the circumferential position of the defect is the circumferential position of 0 ° in the map obtained in step S8.
8. The method of asymmetric ultrasonic guided wave mode based pipe imaging according to claim 7, wherein: in step S7, the magnitude versus circumferential position obtained by the Matlab program modeling includes: the circumferential distribution of longitudinal asymmetric ultrasonic guided wave mode energy and/or the circumferential distribution of torsional asymmetric ultrasonic guided wave mode energy.
9. The method of asymmetric ultrasonic guided wave mode based pipe imaging according to claim 8, wherein: in step S2, when the longitudinal asymmetric ultrasonic guided-wave mode is performed to position the defect of the pipeline in the circumferential direction and the axial direction, the direction of the magnetic field of the magnetostrictive material is made to be consistent with the axial direction of the pipeline by magnetization; when the asymmetric ultrasonic guided wave mode is twisted to position the defect of the pipeline in the circumferential direction and the axial direction, the direction of the magnetic field of the magnetostrictive material is consistent with the circumferential direction of the pipeline through magnetization.
Technical Field
The invention belongs to the technical field of nondestructive testing, and particularly relates to a pipeline imaging method based on an asymmetric ultrasonic guided wave mode, which is used for imaging a pipeline in a self-excitation and self-receiving measurement mode so as to acquire information of axial and circumferential positions of defects in the pipeline.
Background
Pipeline transportation is one of five major transportation industries and is known as the artery of national economy. The mileage of oil and gas pipe networks in China exceeds 10 kilometers in 2012, and the safety problem is the focus of social public, government and enterprise attention. During the service period of the pipeline, due to the fact that the working environment is severe, such as corrosion, excavation and the like, the pipeline is prone to cracking, defects are generated to cause pipeline leakage, and the pipeline needs to be repaired urgently. A prerequisite for a pipeline emergency repair is the ability to accurately determine the specific location in the pipeline at which a rupture for various reasons has occurred. For some larger diameter pipes it is not sufficient to determine only the axial location of the pipe break, so simultaneous circumferential and axial positioning of defects in the pipe is necessary. The pipeline imaging can visually observe defects in the pipeline and solve the problems of circumferential and axial positioning of the defects.
Ultrasonic guided wave has been widely used in pipeline inspection as a fast and long-distance inspection method, and there are two common ultrasonic guided wave modes for pipeline inspection at present: a longitudinal ultrasonic guided wave mode and a torsional ultrasonic guided wave mode. These two modes are applied to different types of defect detection because of different vibration modes. However, the two commonly used ultrasonic guided wave modes are both of a symmetrical excitation mode, and the circumferential distribution of energy is consistent, so that the circumferential information of the defect cannot be obtained. Therefore, a method for positioning the defect of the pipeline in the circumferential direction and the axial direction is needed, which can detect the circumferential position and the axial position of the defect in the pipeline at the same time. Meanwhile, the measuring mode of self-exciting and self-receiving at the same end of the pipeline can be met, so that the requirement during field measurement is met.
Disclosure of Invention
Aiming at the defects and shortcomings in the prior art, the invention aims to image a pipeline by using an asymmetric ultrasonic guided wave mode to realize circumferential and axial positioning of the defects in the pipeline, so that a pipeline imaging method based on the asymmetric ultrasonic guided wave mode is provided, and the method is realized by using the rule of circumferential energy distribution of the asymmetric ultrasonic guided wave mode in the propagation process and adopting a theoretical model and experimental comparison mode. In addition, the method supports a self-excitation and self-receiving measurement mode, and can adapt to the condition that only one end of a pipeline can be loaded with a sensor in engineering measurement. The invention is suitable for the detection of different defects and simultaneously supports the longitudinal asymmetric ultrasonic guided wave mode and the torsional asymmetric ultrasonic guided wave mode to detect the pipeline.
In order to achieve the purpose, the technical scheme of the invention is as follows: 1) adhering the magnetostrictive material on the pipeline, wherein the adhering range is the circumferential range of the whole pipeline; 2) magnetizing the magnetostrictive material by using a permanent magnet; 3) attaching a flexible printed coil on a magnetostrictive material, wherein the attaching range is half of the whole circumferential range of the pipeline; 4) inputting a sine wave signal modulated by a Hanning window with 5 periods through a flexible printing coil by adopting a self-excitation self-receiving mode, and collecting a receiving signal; 5) rotating the circumferential position of the flexible printed coil on the pipeline at equal angles, and collectingN（N≧ 8) secondary signal; 6) read the collectionNTime corresponding to defect echo in individual signaltBy usingV ∙ t /2 calculating the axial position of the defectL(ii) a 7) Inputting axial position of defect in amplitude and circumferential position programLObtaining the axial position of the asymmetric ultrasonic guided wave modeLA plot of amplitude versus circumferential position; 8) recording the acquisitionNThe amplitude of the defect echo in the signal, which is plottedNA relation graph of the defect echo amplitude of each signal and the circumferential position; 9) and corresponding the circumferential position where the maximum amplitude value is located in the relational graph obtained in the step 8) to the circumferential position where the maximum amplitude value is located in the relational graph obtained in the step 7). The other circumferential positions in the map obtained in step 8) are thus determined. The circumferential position of the defect is the circumferential position of 0 ° in the map obtained in step 8).
The invention specifically adopts the following technical scheme:
a method for pipeline imaging based on asymmetric ultrasonic guided wave mode is characterized in that: installing a sensor at one end of the pipeline, and changing the circumferential position of the sensor in the pipeline by a plurality of times of equal angles of A degrees to acquire signals of the sensor at different circumferential positions of the pipeline, wherein the number of the acquired signals is equal to 360 degrees/A degrees; imaging the whole pipeline by all the acquired signals; the sensor comprises a flexible printed coil and a magnetostrictive material; the magnetostrictive material is used for being stuck on a pipeline; the flexible printed coil is adhered to the magnetostrictive material, and the circumferential coverage range of the flexible printed coil is half of the whole circumferential range of the pipeline.
Furthermore, the leads on the flexible printed coil are connected with each other to form four rows of symmetrical two-to-two-circuit folding circuits which are alternately arranged.
Further, the magnetostrictive material contains 48.94% of iron, 48.75% of cobalt, 0.01% of carbon, 0.05% of silicon, 0.30% of niobium, 0.05% of manganese and 1.90% of vanadium.
Further, the length of the flexible printed coil along the axial direction of the pipeline to be tested is 48mm, and the length along the circumferential direction of the pipeline to be tested is determined according to the diameter of the pipeline to be tested; 40 leads are arranged along the axial direction of the pipeline to be tested, and 39 leads are arranged along the circumferential direction of the pipeline to be tested; the line widths and the intervals of all the conducting wires are respectively 1mm and 0.2 mm; the conducting wires are connected with each other to form four sections of folding circuits, and the width of each section of folding circuit is 12 mm; the flexible printed coil is provided with two bonding pads which are respectively positioned at two ends of the folding circuit.
And further, simulating the circumferential distribution of longitudinal asymmetric ultrasonic guided wave modal energy and/or the circumferential distribution of torsional asymmetric ultrasonic guided wave modal energy through a computer program, and corresponding to the pipeline imaging to obtain the position of the defect.
Further, the method specifically comprises the following steps:
step S1: adhering the magnetostrictive material to a pipeline, wherein the adhering range is the circumferential range of the whole pipeline;
step S2: magnetizing the magnetostrictive material with a permanent magnet;
step S3: adhering the flexible printed coil on a magnetostrictive material, wherein the adhering range is half of the whole circumferential range of the pipeline;
step S4: inputting a sine wave signal modulated by a Hanning window with 5 periods through a flexible printing coil by adopting a self-excitation self-receiving mode, and collecting a receiving signal;
step S5: rotating the circumferential position of the flexible printed coil on the pipeline at equal angles, and collectingNThe sub-signal(s) is (are),N≥8；
step S6: read the collectionNTime corresponding to defect echo in individual signaltBy usingV ∙ t /2 calculating the axial position of the defectL；
Step S7: according to the axial position of the defectLObtaining the axial position of the asymmetric ultrasonic guided wave mode by utilizing the relation between the amplitude obtained by modeling and the circumferential positionLAmplitude versus circumferential position.
Step S8: recording the acquisitionNThe amplitude of the defect echo in the signal, which is plottedNA relation graph of the defect echo amplitude of each signal and the circumferential position;
step S9: corresponding the circumferential position of the maximum amplitude in the relational graph obtained in the step S8 to the circumferential position of the maximum amplitude in the relational graph obtained in the step S7, thereby determining other circumferential positions in the relational graph obtained in the step S8; the circumferential position of the defect is the circumferential position of 0 ° in the map obtained in step S8.
Further, in step S7, the magnitude versus circumferential position obtained by modeling using Matlab program includes: the circumferential distribution of longitudinal asymmetric ultrasonic guided wave mode energy and/or the circumferential distribution of torsional asymmetric ultrasonic guided wave mode energy.
Further, in step S2, when the longitudinal asymmetric ultrasonic guided wave mode is performed to position the defect of the pipe in the circumferential direction and the axial direction, the magnetic field direction of the magnetostrictive material is made to coincide with the axial direction of the pipe by magnetization; when the asymmetric ultrasonic guided wave mode is twisted to position the defect of the pipeline in the circumferential direction and the axial direction, the direction of the magnetic field of the magnetostrictive material is consistent with the circumferential direction of the pipeline through magnetization.
Compared with the prior art, the invention and the optimized scheme thereof have the following beneficial effects:
1. the circumferential and axial position information of the defects in the pipeline can be obtained simultaneously;
2. a circumferential extent that can be used to assess defects;
3. two modes with different vibration modes can be supported: torsional mode and longitudinal mode.
Drawings
The invention is described in further detail below with reference to the following figures and detailed description:
FIG. 1 is a schematic diagram of circumferential and axial positioning of a pipeline defect based on a longitudinal asymmetric ultrasonic guided wave mode according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of circumferential and axial positioning of a pipeline defect based on a torsional asymmetric ultrasonic guided wave mode according to an embodiment of the present invention;
FIG. 3 is a schematic view of a sensor of an embodiment of the present invention at different circumferential positions;
FIG. 4 is a theoretical and simulated energy circumferential distribution diagram of a 200kHz asymmetric longitudinal ultrasonic guided wave mode in a 700mm axial propagation distance of a steel pipeline in an embodiment of the invention;
FIG. 5 is a theoretical and simulated energy circumferential distribution diagram of a 120kHz asymmetric longitudinal ultrasonic guided wave mode within a 500mm axial propagation distance of a steel pipeline in an embodiment of the invention;
FIG. 6 is an imaging diagram of an asymmetric longitudinal ultrasonic guided wave mode of 200kHz for a steel pipeline with a defect of 450mm according to an embodiment of the invention;
FIG. 7 is an imaging diagram of 120kHz asymmetric longitudinal ultrasonic guided wave mode to a steel pipeline with a defect of 450mm according to an embodiment of the invention;
FIG. 8 is a schematic diagram of a flexible printed coil structure according to an embodiment of the present invention;
fig. 9 is a schematic diagram of the working principle of the flexible printed coil according to the embodiment of the invention.
Wherein: 1-flexible printed coil, 2-magnetostrictive material.
Detailed Description
In order to make the features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail as follows:
it should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.
Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the exemplary embodiments below are not intended to represent all implementations consistent with the present disclosure. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present disclosure, as detailed in the appended claims.
The terminology used in the present disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used in this disclosure and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.
It should be understood that although the terms first, second, and third may be used in this disclosure to describe various information, this information should not be limited to these terms. These terms are only used to distinguish one type of information from another. For example, first information may also be referred to as second information, and similarly, second information may also be referred to as first information, without departing from the scope of the present disclosure. The word "if" as used herein may be interpreted as "at … …" or "when … …" or "in response to a determination", depending on the context.
The invention is further explained below with reference to the drawings and the embodiments.
As shown in fig. 1 to 9, the scheme provided by the present embodiment mainly includes:
considering that the sensors for exciting the asymmetric ultrasonic guided wave mode are divided into two types, one is a sensor for exciting the longitudinal asymmetric ultrasonic guided wave mode, and the other is a sensor for exciting the torsional asymmetric ultrasonic guided wave mode. The method provided by the invention can support the positioning of the defects in the pipeline by the two different ultrasonic guided wave modes.
Two types of sensors are implemented by: 1. efficiently exciting an asymmetric longitudinal and torsional ultrasonic guided wave mode flexible printed coil 1; 2. a magnetostrictive material 2; 3. a circumferential distribution program of longitudinal asymmetric ultrasonic guided wave modal energy; 4. a circumferential distribution program of torsional asymmetric ultrasonic guided wave modal energy; 5. and (3) a pipeline imaging program based on the asymmetric ultrasonic guided wave mode.
The sensor is arranged at one end of the pipeline, and the circumferential coverage range of the sensor is half of the whole circumferential direction of the pipeline. Signals of the sensors at different circumferential positions of the pipeline are acquired by changing the positions of the sensors in the circumferential direction of the pipeline by equal angles (A degrees) for multiple times. The number of signals acquired is equal to 360 °/a °. All the acquired signals are used to image the entire pipe. The present invention can determine the circumferential and axial location of defects in a pipe by imaging the pipe. The parts are characterized as follows:
1. as shown in fig. 8 and 9, the present embodiment provides a flexible printed coil design with a width (length along the axial direction of the pipe to be measured) of 48 mm. The length (in the axial direction of the pipe to be tested) depends on the pipe diameter of the pipe to be tested. There are 40 conductive lines perpendicular to the width direction and 39 conductive lines perpendicular to the length direction. The line widths and the intervals of all the conducting wires are 1mm and 0.2 mm. The wires are connected with each other to form four sections of folding circuits, so that the wires on the flexible printed coil are connected with each other to form four rows of symmetrical folding circuits which are alternately arranged and are folded twice. The width of each section of the folding circuit is 12 mm. The flexible printed coil has two pads respectively located at two ends of the folding circuit.
2. For magnetostrictive materials, the composition comprises: 48.94% of iron, 48.75% of cobalt, 0.01% of carbon, 0.05% of silicon, 0.30% of niobium, 0.05% of manganese and 1.90% of vanadium. The thickness is 0.152 mm.
3. And for the circumferential distribution program of the longitudinal asymmetric ultrasonic guided wave mode energy, predicting the circumferential distribution of the energy when the longitudinal asymmetric ultrasonic guided wave mode propagates to different axial distances, and modeling by Matlab. Taking a peripheral distribution Matlab program of 200kHz longitudinal asymmetric ultrasonic guided wave modal energy of a steel pipe with an outer diameter of 34mm and a wall thickness of 4mm as an example, the program code is as follows:
theta=0:(pi/100):(2*pi);
z = 350%
L=25;
M=1;
A=zeros(1,3);
f=200;
Ph0= 5449.75%% Ph0 is the pipeline 200kHz L (0,2) modal phase velocity
Ph1= 5697.13%% Ph1 is the modal phase velocity of the pipeline at 200kHz F (1,3)
Ph2= 6713.67%% Ph2 is the modal phase velocity of the pipeline at 200kHz F (2,3)
z0= 8.93E-09%% z0 is the axial displacement of the modal outer diameter of the conduit at 200kHz L (0,2)
z1= 8.79E-09%% z1 is the axial displacement of the modal outer diameter of the conduit at 200kHz F (1,3)
z2= 8.23E-09%% z2 is the axial displacement of the modal outer diameter of the conduit at 200kHz F (2,3)
ef0= 0.420607534%% ef0 is the energy flow of the 200kHz L (0,2) mode of the pipeline
ef1= 0.420240843%% ef1 is the energy flow of the 200kHz F (1,3) mode of the pipeline
ef2= 0.419229827%% ef2 is the energy flow of the 200kHz F (2,3) mode of the pipeline
circum0=cos(0*theta);
e0=exp((-i)*(2*pi*f/Ph0)*z);
vT0=ef0*2*pi;
p10=1;
p20=sin(2*pi*f/Ph0*L);
A0=z0*p10*p20/vT0;
Am0=e0*circum0*A0;
circum1=cos(1*theta);
e1=exp((-i)*(2*pi*f/Ph1)*z);
vT1=ef1*pi;
p11=2*sin(pi/M/2*1)/(pi/M*1);
p21=sin(2*pi*f/Ph1*L)*(2*pi*f/Ph0)/(2*pi*f/Ph1);
A1=z1*p11*p21/vT1;
Am1=e1*circum1*A1;
circum2=cos(2*theta);
e2=exp((-i)*(2*pi*f/Ph2)*z);
vT2=ef2*pi;
p12=2*sin(pi/M/2*2)/(pi/M*2);
p22=sin(2*pi*f/Ph2*L)*(2*pi*f/Ph0)/(2*pi*f/Ph2);
A2=z2*p12*p22/vT2;
Am2=e2*circum2*A2;
A(1)=A0;
A(2)=A1;
A(3)=A2;
A=abs(A);
B=mapminmax(A,0,1);
AP=Am0+Am1+Am2;
AAP=abs(AP);。
4. For the circumferential distribution program of the torsional asymmetric ultrasonic guided wave mode energy, the circumferential distribution of the energy when the torsional asymmetric ultrasonic guided wave mode propagates to different axial distances can be predicted in the same way. Taking a peripheral distribution Matlab program of 120kHz torsional asymmetric ultrasonic guided wave modal energy of a steel pipe with the outer diameter of 34mm and the wall thickness of 4mm as an example, the program is as follows:
theta=0:(pi/100):(2*pi);
z = 450%
L=25;
M=1;
A=zeros(1,4);
f=120;
Ph0= 3260%% Ph0 is the pipeline 120kHz T (0,1) modal phase velocity
Ph1= 3468.07%% Ph1 is the modal phase velocity of the pipe at 120kHz F (1,2)
Ph2= 4266.86%% Ph2 is the modal phase velocity of the pipe at 120kHz F (2,2)
T0= 2.13E-08%% T0 is the tangential displacement of the conduit 120kHz T (0,1) modal outside diameter
t1= 2.12E-08%% t1 is the tangential displacement of the conduit 120kHz F (1,2) modal outside diameter
t2= 1.92E-08%% t2 is the tangential displacement of the conduit 120kHz F (2,2) modal outside diameter
ef0= 6.96E-01%% ef0 is the energy flow of the 120kHz T (0,1) mode of the pipeline
ef1= 0.697827402%% ef1 is the energy flow of the 120kHz F (1,2) mode of the pipeline
ef2= 0.710460431%% ef2 is the energy flow of the 120kHz F (2,2) mode of the pipeline
circum0=cos(0*theta);
e0=exp((-i)*(2*pi*f/Ph0)*z);
vT0=ef0*2*pi;
p10=1;
p20=sin(2*pi*f/Ph0*L);
A0=t0*p10*p20/vT0;
Am0=e0*circum0*A0;
circum1=cos(1*theta);
e1=exp((-i)*(2*pi*f/Ph1)*z);
vT1=ef1*pi;
p11=2*sin(pi/M/2*1)/(pi/M*1);
p21=sin(2*pi*f/Ph1*L)*(2*pi*f/Ph0)/(2*pi*f/Ph1);
A1=t1*p11*p21/vT1;
Am1=e1*circum1*A1;
circum2=cos(2*theta);
e2=exp((-i)*(2*pi*f/Ph2)*z);
vT2=ef2*pi;
p12=2*sin(pi/M/2*2)/(pi/M*2);
p22=sin(2*pi*f/Ph2*L)*(2*pi*f/Ph0)/(2*pi*f/Ph2);
A2=t2*p12*p22/vT2;
Am2=e2*circum2*A2;
A(1)=A0;
A(2)=A1;
A(3)=A2;
A=abs(A);
B=mapminmax(A,0,1);
AP=Am0+Am1+Am2;
AAP=abs(AP);。
5. For the pipeline imaging program based on the asymmetric ultrasonic guided wave mode, which is used for imaging the pipeline, the program can be realized by Matlab as follows:
pname=fileparts(mfilename('fullpath'));
for index_n=1:1:16;
name_a='WFM';
b1=int2str(floor(mod(index_n,100)/10));
b2=int2str(mod(index_n,10));
name_b=strcat(b1,b2);
name_c='.csv';
fname=strcat(name_a,name_b,name_c);
read_temp=dlmread(strcat(pname,'\',fname),',',1,0);
Iamg(:,index_n)=read_temp(:,2);
Iamg(:,index_n)=abs(Iamg(:,index_n));
Iamg(1:3500,index_n)=0;
end
y_axis=read_temp(:,1);
x_axis=[0:(360/15):360];
for i=1:16
x0_axis(i)=abs(x_axis(i)-12);
end
x0_axis(1)=360-x0_axis(1);
figure(1);
pcolor(x_axis,y_axis,Iamg);
shading interp;。
the method of the embodiment specifically adopts the following steps: 1) adhering the magnetostrictive material on the pipeline, wherein the adhering range is the circumferential range of the whole pipeline; 2) magnetizing the magnetostrictive material by using a permanent magnet; 3) attaching a flexible printed coil on a magnetostrictive material, wherein the attaching range is half of the whole circumferential range of the pipeline; 4) inputting a sine wave signal modulated by a Hanning window with 5 periods through a flexible printing coil by adopting a self-excitation self-receiving mode, and collecting a receiving signal; 5) rotating the circumferential position of the flexible printed coil on the pipeline at equal angles, and collectingN（N≧ 8) secondary signal; 6) read the collectionNTime corresponding to defect echo in individual signaltBy usingV ∙ t /2 calculating the axial position of the defectL(ii) a 7) Inputting axial position of defect in amplitude and circumferential position programLObtaining the axial position of the asymmetric ultrasonic guided wave modeLA plot of amplitude versus circumferential position; 8) recording the acquisitionNDefect in signalAmplitude of the wave, plotting thisNA relation graph of the defect echo amplitude of each signal and the circumferential position; 9) and corresponding the circumferential position where the maximum amplitude value is located in the relational graph obtained in the step 8) to the circumferential position where the maximum amplitude value is located in the relational graph obtained in the step 7). The other circumferential positions in the map obtained in step 8) are thus determined. The circumferential position of the defect is the circumferential position of 0 ° in the map obtained in step 8).
The scheme of the present invention is further shown below in connection with two specific examples:
as shown in fig. 1, an embodiment of circumferential and axial positioning of a pipeline defect for a longitudinal asymmetric ultrasonic guided wave mode is as follows:
1) firstly, adhering a magnetostrictive material on a pipeline, wherein the adhering range is the circumferential range of the whole pipeline. Generally, in order to increase the axial magnetic field strength of a magnetostrictive material, it is necessary to increase the axial length of the magnetostrictive material;
2) and magnetizing the magnetostrictive material by using a permanent magnet to ensure that the direction of the magnetic field of the magnetostrictive material is consistent with the axial direction of the pipeline.
3) Attaching a flexible printed coil on a magnetostrictive material, wherein the attaching range is half of the whole circumferential range of the pipeline;
4) inputting a sine wave signal modulated by a Hanning window with 5 periods through a flexible printing coil by adopting a self-excitation self-receiving mode, and collecting a receiving signal;
5) rotating the circumferential position of the flexible printed coil on the pipeline at equal angles, and collectingN（N≧ 8) secondary signal;
6) read the collectionNTime corresponding to defect echo in individual signaltBy usingV ∙ t /2 calculating the axial position of the defectL；
7) Inputting axial position of defect in amplitude and circumferential position program based on longitudinal asymmetric ultrasonic guided wave modeLObtaining the axial position of the longitudinal asymmetric ultrasonic guided wave modeLA plot of amplitude versus circumferential position;
8) recording the acquisitionNThe amplitude of the defect echo in the signal, which is plottedNAmplitude of defect echo of individual signalA map of circumferential position;
9) the circumferential position of the maximum amplitude in the relational graph obtained in the step 8) corresponds to the circumferential position of the maximum amplitude in the relational graph obtained in the step 7), and other circumferential positions in the relational graph obtained in the step 8) are determined accordingly. The circumferential position of the defect is the circumferential position of 0 ° in the map obtained in step 8).
As shown in fig. 2, an embodiment of circumferential and axial positioning of a pipeline defect for a torsional asymmetric ultrasonic guided-wave mode is as follows:
1) firstly, sticking a magnetostrictive material on a pipeline, wherein the sticking range is the circumferential range of the whole pipeline;
2) magnetizing the magnetostrictive material by using a permanent magnet to ensure that the magnetic field direction of the magnetostrictive material is consistent with the circumferential direction of the pipeline;
3) attaching a flexible printed coil on a magnetostrictive material, wherein the attaching range is half of the whole circumferential range of the pipeline;
4) inputting a sine wave signal modulated by a Hanning window with 5 periods through a flexible printing coil by adopting a self-excitation self-receiving mode, and collecting a receiving signal;
5) rotating the circumferential position of the flexible printed coil on the pipeline at equal angles, and collectingN（N≧ 8) secondary signal;
6) read the collectionNTime corresponding to defect echo in individual signaltBy usingV ∙ t/2 calculating the axial position of the defectL；
7) Inputting axial positions of defects in amplitude and circumferential position programs based on torsional asymmetric ultrasonic guided wave modesLObtaining the axial position of the torsional asymmetric ultrasonic guided wave modeLA plot of amplitude versus circumferential position;
8) recording the acquisitionNThe amplitude of the defect echo in the signal, which is plottedNA relation graph of the defect echo amplitude of each signal and the circumferential position;
9) the circumferential position of the maximum amplitude in the relational graph obtained in the step 8) corresponds to the circumferential position of the maximum amplitude in the relational graph obtained in the step 7), and other circumferential positions in the relational graph obtained in the step 8) are determined accordingly. The circumferential position of the defect is the circumferential position of 0 ° in the map obtained in step 8).
As shown in fig. 5-7, the present embodiment is correspondingly simulated and implemented according to the above design, and the test results all prove the efficacy of the solution of the present embodiment.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the embodiments of the invention without departing from the spirit and scope of the invention, which is to be covered by the claims.
The present invention is not limited to the above preferred embodiments, and all other various methods for imaging a pipe based on asymmetric ultrasonic guided wave mode can be derived from the teaching of the present invention.