CN104155368A - Method and device for identifying cracking angle of pipeline based on phase locus partitioned by round window - Google Patents

Abstract

The invention discloses a method and a device for identifying a cracking angle of a pipeline based on a phase locus partitioned by a round window. The method comprises the following steps: (1) stimulating ultrasonic guided wave signals on an end face of one side of the pipeline to enable ultrasonic guided waves to traverse all positions of the pipeline; (2) collecting echo signals at a site 10mm away from a stimulation end by virtue of two sensors, and recording a time history curve of ultrasonic guided waves propagated in the pipeline; (3) calculating the detected echo signals by virtue of a Duffing chaotic system to obtain a phase locus of the ultrasonic guided wave signals, portioning the phase locus into two parts in and out of the round window by virtue of the round window so as to realize conversion from a two-dimensional phase diagram to a one-dimensional time signal, judging whether the pipeline is damaged or not according to a border line equation of the round window, if the pipeline is damaged, extracting time points of the ultrasonic guided wave signals entering the round window, and calculating by virtue of a time difference of crack information obtained by the two sensors, so as to obtain the information of the cracking angle of the pipeline. The method can prejudge the crack damage condition, thus having a practical engineering application value.

Description

Cut apart method and the device of phase recognition pipeline crack angle based on oeil de boeuf

Technical field

The present invention relates to the recognition methods of flaw angle information in a kind of pipeline, especially a kind of method of cutting apart phase recognition pipeline crack angle based on oeil de boeuf, belongs to the damage check technical field of pipeline transportation industry.

Background technology

Pipeline transportation is described as the fifth-largest means of transport after railway, highway, aviation, sea-freight, the important main city part of urban lifeline engineering, but because the factors such as buried (or setting up) area surroundings of burn into and artificial destruction are on active service and have been formed potential threat the safety of pipeline.Be necessary the damage status of pipeline to analyze identification for this reason.

For preventing the generation of pipeline serious accident, China reaches several hundred million units for oil and gas pipes maintenance cost every year, and increases year by year.But due to the restriction of examined means, pipe damage situation is most not clear, often cause blindly excavation, blindness to scrap, maintenance lacks science, thereby causes the huge waste of human and material resources.The propagation of low frequency stress ripple in bounded structure is called as supersonic guide-wave, and last century end, supersonic guide-wave is successfully difficult for directly measuring the Non-Destructive Testing of structure and assessing for buried pipeline and other.Ultrasonic guided wave detecting can be utilized echoed signal analysis,, when guided wave runs into defect of pipeline in communication process, has part guided wave and reflects, and by analyzing ultrasonic echo feature, can judge in distance test point position how far and may have defect.Compared with conventional ultrasonic wave detection technique, supersonic guide-wave excites along waveguiding structure length direction, and its sensing range is " line " but not " point ", and its sensing range can reach 50～100m.Because stress wave belongs to bodily wave propagation, therefore it can be realized body structure surface and inner complete detection, and it is fast to have detection speed, and sensing range is wide and without removing the advantages such as overlayer.

Summary of the invention

The object of the invention is the defect in order to solve conventional ultrasonic wave detection technique, a kind of method of cutting apart phase recognition pipeline crack angle based on oeil de boeuf is provided, the method utilizes supersonic guide-wave to scan whole segment pipe, can identify ducted flaw angle information, anticipation Crack Damage degree.

Another object of the present invention is to provide a kind of device of cutting apart phase recognition pipeline crack angle based on oeil de boeuf.

Object of the present invention can be by taking following technical scheme to reach:

Cut apart the method for phase recognition pipeline crack angle based on oeil de boeuf, it is characterized in that comprising the following steps:

1) arbitrary waveform signal generator generates the modulation signal needing, and amplifies by power amplifier, remakes the piezoelectric ring for pipeline one side end face, and excitation ultrasound guided wave signals makes supersonic guide-wave travel through all positions of pipeline;

2) excite end 10mm place to collect echoed signal by the piezoceramic transducer of two segment distances of being separated by distance, wherein echoed signal comprises end face echoed signal, noise signal and is submerged in the flaw echoes in noise; And record by digital oscilloscope the time history curve that supersonic guide-wave is propagated in pipeline, by digital oscilloscope by record communication to computing machine;

3) utilize Du Fen chaos system detection of echoes signal to be calculated to the phase path of ultrasonic guided wave signals; recycling oeil de boeuf is cut apart phase path; phase path is divided in oeil de boeuf and the outer two parts of oeil de boeuf; realize the conversion from two-dimentional phasor to one dimension time signal; judge whether damage according to oeil de boeuf boundary line equation; if have; extract the ultrasonic guided wave signals time point that enters oeil de boeuf; the mistiming of the crack information obtaining by two sensors, calculate pipeline crack angle information.

Concrete, the function expression of described ultrasonic guided wave signals is:

$s\left(t\right)=\left[\frac{1}{2}(1-\cos \frac{2\mathrm{\π}{f}_{c}t}{n})\right]\sin \left(2\mathrm{\π}{f}_{c}t\right)---\left(1\right)$

Wherein, f _cfor applying the frequency of signal, t is the time, and n is the cycle.

Concrete, step 3) the described Du Fen of utilization chaos system calculates the phase path of ultrasonic guided wave signals to detection of echoes signal, specific as follows:

A) choose Du Fen chaos system, as shown in the formula:

$\stackrel{\·\·}{x}=k\stackrel{\·}{x}-x^3+x^5=F\cos \left(\mathrm{\ωt}\right)+\stackrel{\‾}{s}\left(t\right)---\left(2\right)$

Wherein k is damping ratio, Fcos (ω is t) driving force item, for signal to be detected;

B) choose displacement x and speed v formula (2) is rewritten, the type that is improved Du Fen chaos system, as shown in the formula:

$\left.\begin{array}{c}\stackrel{\·}{x}=v\\ \stackrel{\·}{v}=-\mathrm{kv}+x^3-x^5+F\cos \left(\mathrm{\ωt}\right)+\stackrel{\‾}{S}\left(t\right)\end{array}\right\}---\left(3\right)$

C), by normalized detection of echoes signal input type (3), in the time having ultrasonic guided wave signals, the phase path of modified Du Fen chaos system can change, and is chaos state by large period state transformation.

Concrete, step b) in, try to achieve the threshold value of formula (3) by Melnikov method, expression formula is as follows:

$\frac{F}{k}=R\left(\mathrm{\ω}\right)=\frac{4\cosh (\mathrm{\π\ω}/2)}{3\sqrt{2}\mathrm{\π\ω}}---\left(4\right)$

Wherein, F is driving force, and ω is driving force frequency, and ω=2 π 0.07rad/ μ s ≈ 0.439823rad/ μ s is set; When time, may there is chaos in system.

Concrete, step b) in, use high precision fourth-order Runge-Kutta method to solve formula (3), calculating initial value design is x=0, k=0.5, ω=0.439823.

Concrete, choosing of described driving force F is as follows:

In the time that driving force F value increases gradually by 0, modified Du Fen chaos system phase path experience fixed point and each cycle, progress into chaos state, large period state and strange attractor, finally choose F=0.429, be positioned at the critical value of large period state and attractor as modified Du Fen chaos system.

Concrete, step 3) the described oeil de boeuf that utilizes cuts apart phase path, phase path is divided in oeil de boeuf and the outer two parts of oeil de boeuf, realizes the conversion from two-dimentional phasor to one dimension time signal, specific as follows:

A) in Du Fen chaos system phase path, set up and the disjoint oeil de boeuf of this phase path, concrete oeil de boeuf boundary line equation is:

$\stackrel{\&OverBar;}{y}\left(t\right)=\left\{\begin{array}{cc}1& \sqrt{{(x-1)}^2+v^2}<R\\ 0& \sqrt{{(x-1)}^2+v^2}>R\end{array}\right.---\left(5\right)$

In formula, the radius that R is oeil de boeuf, high level 1 indicates damage, low level 0 represents not damaged;

B) find suitable oeil de boeuf radius R, the ultrasonic guided wave signals quantity that makes to enter oeil de boeuf is fully many, and can capture signaling point accurately, chooses R=0.1159.

Concrete, step 3) described extraction enters the ultrasonic guided wave signals time point of oeil de boeuf, the mistiming of the crack information obtaining by two sensors, calculate pipeline crack angle information, specific as follows:

A) extract and enter the ultrasonic guided wave signals point of oeil de boeuf: the corresponding time t1 of initial ultrasound guided wave signals and the t2 that obtain respectively two sensor the data obtaineds and enter oeil de boeuf;

B) actual range between two piezoceramic transducers is designated as L1, utilizes the mistiming between time t2 and t1 to obtain distance L 2, as follows:

L2＝0.5C(t2-t1) (6)

Wherein, C is supersonic guide-wave velocity of wave;

C) utilize following formula to try to achieve flaw angle:

θ＝arctan(L2/L1) (7)

Wherein, θ is the flaw angle of trying to achieve.

Another object of the present invention can be by taking following technical scheme to reach:

Cut apart the device of phase recognition pipeline crack angle based on oeil de boeuf, it is characterized in that: comprise arbitrary waveform signal generator, power amplifier, piezoelectric ring, digital oscilloscope, computing machine and two piezoceramic transducers, described piezoelectric ring is arranged on pipeline one side end face, described two piezoceramic transducers are arranged on the 10mm place apart from piezoelectric ring position, and the segment distance of being separated by between two piezoceramic transducers; Described arbitrary waveform signal generator, power amplifier and piezoelectric ring are connected successively, and described arbitrary waveform signal generator is connected with two passages of digital oscilloscope respectively with piezoceramic transducer, and described digital oscilloscope is connected with computing machine; Wherein:

Described arbitrary waveform signal generator, for generating the modulation signal needing;

Described power amplifier, amplifies for the modulation signal that arbitrary waveform signal generator is generated, and acts on piezoelectric ring, excitation ultrasound guided wave signals;

Described piezoceramic transducer, for collecting echoed signal;

Described digital oscilloscope, the time history curve of propagating at pipeline for recording supersonic guide-wave, and by record communication to computing machine;

Described computing machine; for utilizing Du Fen chaos system detection of echoes signal to be calculated to the phase path of ultrasonic guided wave signals; recycling oeil de boeuf is cut apart phase path; phase path is divided in oeil de boeuf and the outer two parts of oeil de boeuf; realize the conversion from two-dimentional phasor to one dimension time signal; judge whether damage according to oeil de boeuf boundary line equation; if have; extract the ultrasonic guided wave signals time point that enters oeil de boeuf; the mistiming of the crack information obtaining by two sensors, calculate pipeline crack angle information.

The present invention has following beneficial effect with respect to prior art:

1, the inventive method and device can detect ducted defect by supersonic guide-wave technology, the defect damage that is suitable for long lines detects, utilize the immunity of Du Fen chaos system to noise, cut apart Du Fen chaos system phase path by oeil de boeuf, can identify accurately, fast ducted flaw angle information, anticipation Crack Damage degree, is convenient to staff and keeps in repair, and has actual engineering using value.

2, the inventive method and device can utilize existing domestic and international pipe detection facility, adopt both economical effective detection method, can faster obtain the concrete angle of crack defect in pipeline, have very important reality and economic implications.

Brief description of the drawings

Fig. 1 is that the present invention identifies the apparatus structure schematic diagram of cutting apart phase recognition pipeline crack angle based on oeil de boeuf.

Fig. 2 is that the present invention identifies the method flow diagram of cutting apart phase recognition pipeline crack angle based on oeil de boeuf.

Fig. 3 is the ultrasonic guided wave signals curve map applying.

Fig. 4 is the time history curve map that the supersonic guide-wave of record is propagated in pipeline.

Fig. 5 a-Fig. 5 e is the differentiation schematic diagram of driving force modified Du Fen oscillator system phase path figure while increasing gradually by 0.

Fig. 6 a is the flaw echoes curve map being intercepted by Fig. 4.

Fig. 6 b is phase path schematic diagram flaw echoes being detected by modified Du Fen chaos system.

Fig. 7 is that oeil de boeuf is cut apart phase path schematic diagram.

Fig. 8 is that flaw angle calculates schematic diagram.

Embodiment

Embodiment 1:

As shown in Figure 1, the device of the present embodiment identification pipeline crack angle comprises arbitrary waveform signal generator (adopting AFG3252), power amplifier (adopting AG1020), piezoelectric ring, digital oscilloscope (adopting DPO4054B), computing machine and 16 piezoceramic transducers, described piezoelectric ring is arranged on pipeline one side end face, described two piezoceramic transducers are arranged on the 10mm place apart from piezoelectric ring position, and the segment distance of being separated by between two piezoceramic transducers, be designated as L1, in the present embodiment, the numerical value of L1 is 9.24mm; Described arbitrary waveform signal generator, power amplifier and piezoelectric ring are connected successively, described arbitrary waveform signal generator is connected with two passages (passage 1 and passage 2) of digital oscilloscope respectively with piezoceramic transducer, and described digital oscilloscope is connected with computing machine.

As shown in Figure 2, the method for the present embodiment identification pipeline crack angle, taking pipeline test specimen as example, comprises the following steps:

1) arbitrary waveform signal generator generates the modulation signal needing, and amplifies by power amplifier, remakes the piezoelectric ring for pipeline test specimen one side end face, and excitation ultrasound guided wave signals makes supersonic guide-wave travel through all positions of pipeline; The function expression of ultrasonic guided wave signals is:

$s\left(t\right)=\left[\frac{1}{2}(1-\cos \frac{2\mathrm{\&pi;}{f}_{c}t}{n})\right]\sin \left(2\mathrm{\&pi;}{f}_{c}t\right)---\left(1\right)$

Wherein, f _cfor applying the frequency of signal, t is the time, and n is the cycle, and what the present embodiment applied is the ultrasonic guided wave signals of 10 cycles, 70KHz frequency, as shown in Figure 3;

2) by excite two piezoceramic transducers at end 10mm place to collect echoed signal in distance, wherein echoed signal comprises end face echoed signal, noise signal and is submerged in the flaw echoes in noise; And record by digital oscilloscope the time history curve that supersonic guide-wave is propagated in pipeline, as shown in Figure 4, by digital oscilloscope by record communication to computing machine, in computing machine, perform step 3)～5);

3) utilize Du Fen chaos system detection of echoes signal to be calculated to the phase path of ultrasonic guided wave signals, specific as follows:

A) choose Du Fen chaos system, as shown in the formula:

$\stackrel{\&CenterDot;\&CenterDot;}{x}=k\stackrel{\&CenterDot;}{x}-x^3+x^5=F\cos \left(\mathrm{\&omega;t}\right)+\stackrel{\&OverBar;}{s}\left(t\right)---\left(2\right)$

Wherein k is damping ratio, Fcos (ω is t) driving force item, for signal to be detected;

B) choose displacement x and speed v formula (2) is rewritten, the type that is improved Du Fen chaos system, as shown in the formula:

$\left.\begin{array}{c}\stackrel{\&CenterDot;}{x}=v\\ \stackrel{\&CenterDot;}{v}=-\mathrm{kv}+x^3-x^5+F\cos \left(\mathrm{\&omega;t}\right)+\stackrel{\&OverBar;}{S}\left(t\right)\end{array}\right\}---\left(3\right)$

C) try to achieve the threshold value of modified Du Fen chaos system: try to achieve the threshold value of formula (3) by Melnikov method, expression formula is as follows:

$\frac{F}{k}=R\left(\mathrm{\&omega;}\right)=\frac{4\cosh (\mathrm{\&pi;\&omega;}/2)}{3\sqrt{2}\mathrm{\&pi;\&omega;}}---\left(4\right)$

Wherein, F is driving force, and ω is driving force frequency, and ω=2 π 0.07rad/ μ s ≈ 0.439823rad/ μ s is set; When time, may there is chaos in system.

D) use high precision fourth-order Runge-Kutta method to solve formula (3), calculating initial value design is x=0, k=0.5, ω=0.439823.

E) sample frequency of the present embodiment is 100/ μ s, and in order to meet accuracy requirement, step-length is set as 0.01 μ s.Along with the value of F increases gradually, do not consider input signal, the phase path figure trying to achieve is (value of F is followed successively by 0,0.200,0.260,0.429 and 0.668) as shown in Fig. 5 a-5e;

F) choose driving force F: shown in Fig. 5 a-5e, in the time that driving force F value increases gradually by 0, modified Du Fen chaos system phase path experience fixed point and each cycle, progress into chaos state, large period state and strange attractor, finally choose F=0.429, be positioned at the critical value of large period state and attractor as modified Du Fen chaos system;

G) flaw echoes of cut-away view 4 as shown in Figure 6 a, is normalized detection of echoes signal, and normalization formula is $\stackrel{\&OverBar;}{s}{\left(t\right)}^{\&prime;}=\{\stackrel{\&OverBar;}{s}\left(t\right)-\stackrel{\&OverBar;}{s}{\left(t\right)}_{\min }\}/\{\stackrel{\&OverBar;}{s}{\left(t\right)}_{\max }-\stackrel{\&OverBar;}{s}{\left(t\right)}_{\min }\},$ By the detection of echoes signal input type (3) after normalization, can see while having ultrasonic guided wave signals, the phase path of modified Du Fen chaos system can change, and is chaos state, as shown in Figure 6 b by large period state transformation;

4) utilize oeil de boeuf to cut apart phase path, phase path is divided in oeil de boeuf and the outer two parts of oeil de boeuf, realize the conversion from two-dimentional phasor to one dimension time signal, specific as follows:

A) in Du Fen chaos system phase path, set up and the disjoint oeil de boeuf of this phase path, concrete oeil de boeuf boundary line equation is:

$\stackrel{\&OverBar;}{y}\left(t\right)=\left\{\begin{array}{cc}1& \sqrt{{(x-1)}^2+v^2}<R\\ 0& \sqrt{{(x-1)}^2+v^2}>R\end{array}\right.---\left(5\right)$

In formula, the radius that R is oeil de boeuf, high level 1 indicates damage, low level 0 represents not damaged; The concrete position of oeil de boeuf as shown in Figure 7.

B) find suitable oeil de boeuf radius R, the ultrasonic guided wave signals quantity that makes to enter oeil de boeuf is fully many, and can capture signaling point accurately, chooses R=0.1159;

5) judged whether damage according to formula (5), if have, extract the ultrasonic guided wave signals point that enters oeil de boeuf, extraction enters the ultrasonic guided wave signals point of oeil de boeuf, obtain respectively the corresponding time t1 of initial ultrasound guided wave signals and t2 that two sensor the data obtaineds enter oeil de boeuf, t1=0.584ms in the present embodiment, t2=0.588ms;

As shown in Figure 8, the actual range L1=9.24mm between two piezoceramic transducers (illustrating two sensors is sensor 1 and sensor 2), utilizes the mistiming between time t2 and t1 to obtain distance L 2, as follows:

L2＝0.5C(t2-t1) (6)

Wherein, C is supersonic guide-wave velocity of wave, and the numerical value of the present embodiment is 5000m/s, therefore L2=10mm;

Utilize following formula to try to achieve flaw angle:

θ＝arctan(L2/L1) (7)

Wherein, θ is the flaw angle of trying to achieve, and calculates θ=47.26 °, and in the present embodiment, the flaw angle of pipeline test specimen reality is 45 °, and error is 2.26 °, has as can be seen here higher precision.

In sum, the inventive method and device are cut apart Du Fen chaos system phase path by oeil de boeuf, can identify accurately, fast ducted flaw angle information, and anticipation Crack Damage degree, is convenient to staff and keeps in repair, and has actual engineering using value.

The above; it is only patent preferred embodiment of the present invention; but protection scope of the present invention is not limited to this; anyly be familiar with those skilled in the art in scope disclosed in this invention; be equal to replacement or changed according to technical scheme of the present invention and inventive concept thereof, all being belonged to protection scope of the present invention.

Claims (9)

1. the method for cutting apart phase recognition pipeline crack angle based on oeil de boeuf, is characterized in that comprising the following steps:

1) arbitrary waveform signal generator generates the modulation signal needing, and amplifies by power amplifier, remakes the piezoelectric ring for pipeline one side end face, and excitation ultrasound guided wave signals makes supersonic guide-wave travel through all positions of pipeline;

2) excite end 10mm place to collect echoed signal by the piezoceramic transducer of two segment distances of being separated by distance, wherein echoed signal comprises end face echoed signal, noise signal and is submerged in the flaw echoes in noise; And record by digital oscilloscope the time history curve that supersonic guide-wave is propagated in pipeline, by digital oscilloscope by record communication to computing machine;

3) utilize Du Fen chaos system detection of echoes signal to be calculated to the phase path of ultrasonic guided wave signals; recycling oeil de boeuf is cut apart phase path; phase path is divided in oeil de boeuf and the outer two parts of oeil de boeuf; realize the conversion from two-dimentional phasor to one dimension time signal; judge whether damage according to oeil de boeuf boundary line equation; if have; extract the ultrasonic guided wave signals time point that enters oeil de boeuf; the mistiming of the crack information obtaining by two sensors, calculate pipeline crack angle information.

2. the method for cutting apart phase recognition pipeline crack angle based on oeil de boeuf according to claim 1, is characterized in that: the function expression of described ultrasonic guided wave signals is:

$s\left(t\right)=\left[\frac{1}{2}(1-\cos \frac{2\mathrm{\&pi;}{f}_{c}t}{n})\right]\sin \left(2\mathrm{\&pi;}{f}_{c}t\right)---\left(1\right)$

Wherein, f _cfor applying the frequency of signal, t is the time, and n is the cycle.

3. the method for cutting apart phase recognition pipeline crack angle based on oeil de boeuf according to claim 1, it is characterized in that: step 3) the described Du Fen of utilization chaos system calculates the phase path of ultrasonic guided wave signals to detection of echoes signal, specific as follows:

A) choose Du Fen chaos system, as shown in the formula:

$\stackrel{\&CenterDot;\&CenterDot;}{x}=k\stackrel{\&CenterDot;}{x}-x^3+x^5=F\cos \left(\mathrm{\&omega;t}\right)+\stackrel{\&OverBar;}{s}\left(t\right)---\left(2\right)$

Wherein k is damping ratio, Fcos (ω is t) driving force item, for signal to be detected;

B) choose displacement x and speed v formula (2) is rewritten, the type that is improved Du Fen chaos system, as shown in the formula:

$\left.\begin{array}{c}\stackrel{\&CenterDot;}{x}=v\\ \stackrel{\&CenterDot;}{v}=-\mathrm{kv}+x^3-x^5+F\cos \left(\mathrm{\&omega;t}\right)+\stackrel{\&OverBar;}{S}\left(t\right)\end{array}\right\}---\left(3\right)$

C), by normalized detection of echoes signal input type (3), in the time having ultrasonic guided wave signals, the phase path of modified Du Fen chaos system can change, and is chaos state by large period state transformation.

4. the method for cutting apart phase recognition pipeline crack angle based on oeil de boeuf according to claim 3, is characterized in that: step b) in, try to achieve the threshold value of formula (3) by Melnikov method, expression formula is as follows:

$\frac{F}{k}=R\left(\mathrm{\&omega;}\right)=\frac{4\cosh (\mathrm{\&pi;\&omega;}/2)}{3\sqrt{2}\mathrm{\&pi;\&omega;}}---\left(4\right)$

Wherein, F is driving force, and ω is driving force frequency, and ω=2 π 0.07rad/ μ s ≈ 0.439823rad/ μ s is set; When time, may there is chaos in system.

5. the method for cutting apart phase recognition pipeline crack angle based on oeil de boeuf according to claim 4, is characterized in that: step b) in, use high precision fourth-order Runge-Kutta method to solve formula (3), calculating initial value design is x=0, k=0.5, ω=0.439823.

6. the method for cutting apart phase recognition pipeline crack angle based on oeil de boeuf according to claim 5, is characterized in that: choosing of described driving force F is as follows:

In the time that driving force F value increases gradually by 0, modified Du Fen chaos system phase path experience fixed point and each cycle, progress into chaos state, large period state and strange attractor, finally choose F=0.429, be positioned at the critical value of large period state and attractor as modified Du Fen chaos system.

7. the method for cutting apart phase recognition pipeline crack angle based on oeil de boeuf according to claim 3; it is characterized in that: step 3) the described oeil de boeuf that utilizes cuts apart phase path; phase path is divided in oeil de boeuf and the outer two parts of oeil de boeuf; realize the conversion from two-dimentional phasor to one dimension time signal, specific as follows:

A) in Du Fen chaos system phase path, set up and the disjoint oeil de boeuf of this phase path, concrete oeil de boeuf boundary line equation is:

$\stackrel{\&OverBar;}{y}\left(t\right)=\left\{\begin{array}{cc}1& \sqrt{{(x-1)}^2+v^2}<R\\ 0& \sqrt{{(x-1)}^2+v^2}>R\end{array}\right.---\left(5\right)$

In formula, the radius that R is oeil de boeuf, high level 1 indicates damage, low level 0 represents not damaged;

B) find suitable oeil de boeuf radius R, the ultrasonic guided wave signals quantity that makes to enter oeil de boeuf is fully many, and can capture signaling point accurately, chooses R=0.1159.

8. the method for cutting apart phase recognition pipeline crack angle based on oeil de boeuf according to claim 7, it is characterized in that: step 3) described extraction enters the ultrasonic guided wave signals time point of oeil de boeuf, the mistiming of the crack information obtaining by two sensors, calculate pipeline crack angle information, specific as follows:

A) extract and enter the ultrasonic guided wave signals point of oeil de boeuf, obtain respectively two sensor the data obtaineds and enter the corresponding time t1 of initial ultrasound guided wave signals and the t2 of oeil de boeuf;

B) actual range between two piezoceramic transducers is designated as L1, utilizes the mistiming between time t2 and t1 to obtain distance L 2, as follows:

L2＝0.5C(t2-t1) (6)

Wherein, C is supersonic guide-wave velocity of wave;

C) utilize following formula to try to achieve flaw angle:

θ＝arctan(L2/L1) (7)

Wherein, θ is the flaw angle of trying to achieve.

9. cut apart the device of phase recognition pipeline crack angle based on oeil de boeuf, it is characterized in that: comprise arbitrary waveform signal generator, power amplifier, piezoelectric ring, digital oscilloscope, computing machine and two piezoceramic transducers, described piezoelectric ring is arranged on pipeline one side end face, described two piezoceramic transducers are arranged on the 10mm place apart from piezoelectric ring position, and the segment distance of being separated by between two piezoceramic transducers; Described arbitrary waveform signal generator, power amplifier and piezoelectric ring are connected successively, and described arbitrary waveform signal generator is connected with two passages of digital oscilloscope respectively with piezoceramic transducer, and described digital oscilloscope is connected with computing machine; Wherein:

Described arbitrary waveform signal generator, for generating the modulation signal needing;

Described power amplifier, amplifies for the modulation signal that arbitrary waveform signal generator is generated, and acts on piezoelectric ring, excitation ultrasound guided wave signals;

Described piezoceramic transducer, for collecting echoed signal;

Described digital oscilloscope, the time history curve of propagating at pipeline for recording supersonic guide-wave, and by record communication to computing machine;

Described computing machine; for utilizing Du Fen chaos system detection of echoes signal to be calculated to the phase path of ultrasonic guided wave signals; recycling oeil de boeuf is cut apart phase path; phase path is divided in oeil de boeuf and the outer two parts of oeil de boeuf; realize the conversion from two-dimentional phasor to one dimension time signal; judge whether damage according to oeil de boeuf boundary line equation; if have; extract the ultrasonic guided wave signals time point that enters oeil de boeuf; the mistiming of the crack information obtaining by two sensors, calculate pipeline crack angle information.