CN109085248B - Method, device and system for positioning impact source of pressure-bearing pipeline wall - Google Patents
Method, device and system for positioning impact source of pressure-bearing pipeline wall Download PDFInfo
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Abstract
The invention provides a method, a device and a system for positioning a pressure-bearing pipeline wall impact source; wherein, the method comprises the following steps: collecting acoustic emission signals generated by impact on the wall of the pressure-bearing pipeline; separating a frequency signal with specified frequency from the acoustic emission signal to obtain a waveform envelope spectrum of the acoustic emission signal; according to a pre-established pressure-bearing pipeline measurement model and the propagation speed of the acoustic emission signals on the wall of the pressure-bearing pipeline, which is obtained through pre-calculation, the time difference of a plurality of sub-signals in the acoustic emission signals reaching a preset search point on the wall of the pressure-bearing pipeline is obtained; and moving the plurality of sub-signals on a time domain according to the time difference, searching a preset search point, and determining the preset search point focused by the wave crests of the plurality of sub-signals as the position of the pressure-bearing pipeline wall impact source. The invention improves the accuracy of positioning the impact source of the pressure-bearing pipeline wall.
Description
Technical Field
The invention relates to the field of pipeline fault positioning, in particular to a method, a device and a system for positioning an impact source of a pressure-bearing pipeline wall.
Background
Pipeline transportation plays an important role in national economy, national defense industrial production, daily life of people and the like. Among them, pressure-bearing pipelines are widely used for long-distance transportation and distribution of natural gas, oil, water and other substances which are easy to flow around the world. Because the pressure-bearing pipeline bears high pressure for a long time, the pipeline can generate an aging phenomenon and be seriously corroded along with the increase of the age of the pipeline; meanwhile, accidents caused by damage and leakage of the pressure-bearing pipeline occur occasionally due to reasons such as mechanical vibration, pipeline impact and artificial damage, and serious damage to human living environment and lives and properties can be directly caused in serious cases. In the prior art, an acoustic emission technology is generally adopted to position an impact source of a pressure-bearing pipeline, but the positioning accuracy is low, and the easy-to-break point of the pipeline is difficult to effectively predict.
Disclosure of Invention
In view of the above, the present invention provides a method, an apparatus and a system for positioning a pressure-bearing pipeline wall impact source, so as to improve the accuracy of positioning the pressure-bearing pipeline wall impact source.
In a first aspect, an embodiment of the present invention provides a method for positioning an impact source of a pressure-bearing pipeline wall, where the method includes: collecting acoustic emission signals generated by impact on the wall of the pressure-bearing pipeline; separating a frequency signal with specified frequency from the acoustic emission signal to obtain a waveform envelope spectrum of the acoustic emission signal; according to a pre-established pressure-bearing pipeline measurement model and the propagation speed of the acoustic emission signals on the wall of the pressure-bearing pipeline, which is obtained through pre-calculation, the time difference of a plurality of sub-signals in the acoustic emission signals reaching a preset search point on the wall of the pressure-bearing pipeline is obtained; and moving the plurality of sub-signals on a time domain according to the time difference, searching a preset search point, and determining the preset search point focused by the wave crests of the plurality of sub-signals as the position of the pressure-bearing pipeline wall impact source.
With reference to the first aspect, an embodiment of the present invention provides a first possible implementation manner of the first aspect, where the method further includes: establishing a pressure-bearing pipeline measurement model according to the position of a sensor arranged on the wall of the pressure-bearing pipeline; and (3) dividing grids on the pipeline wall of the pressure-bearing pipeline measurement model, and determining the grid line intersection points as preset search points.
With reference to the first possible implementation manner of the first aspect, an embodiment of the present invention provides a second possible implementation manner of the first aspect, where six sensors are disposed on a wall of a pressure-bearing pipeline, where four sensors surround a rectangular region and are used to collect sub-signals, and two sensors are respectively located in centers of the rectangular regions at two ends of the pipeline and are used to determine a direction of an impact source.
With reference to the first aspect, an embodiment of the present invention provides a third possible implementation manner of the first aspect, where the step of separating a frequency signal with a specified frequency from the acoustic emission signal to obtain a waveform envelope spectrum of the acoustic emission signal includes: extracting bending wave signals in the acoustic emission signals; and solving the envelope of the waveform of the bending wave signal component by adopting a Hilbert time domain waveform envelope method to obtain a low-frequency narrow-band acoustic emission signal corresponding to the acoustic emission signal.
With reference to the second possible implementation manner of the first aspect, an embodiment of the present invention provides a fourth possible implementation manner of the first aspect, wherein the propagation speed of the acoustic emission signal on the pressure-bearing pipeline wall is obtained by: respectively acquiring sub-signals through two sensors; identifying the time difference of the corresponding sub-signals of the two sensors in a cross-correlation mode; and calculating the propagation speed through a speed distance formula according to the distance between the two sensors and the time difference.
With reference to the first possible implementation manner of the first aspect, an embodiment of the present invention provides a fifth possible implementation manner of the first aspect, where the step of obtaining, according to a pre-established pressure-bearing pipeline measurement model and a pre-calculated propagation velocity of the obtained acoustic emission signal on a pressure-bearing pipeline wall, a time difference of acquisition of a plurality of sub-signals in the acoustic emission signal includes: calculating the distance between any two grid line intersection points on the pipeline wall; and calculating the time difference of the plurality of sub-signals in the acoustic emission signal reaching each grid line intersection point according to the distance and the propagation speed.
With reference to the first aspect, an embodiment of the present invention provides a sixth possible implementation manner of the first aspect, where the step of moving the multiple sub-signals in the time domain according to the time difference, searching for a preset search point, and determining a preset search point where peaks of the multiple sub-signals are focused as the location of the pressure-bearing pipeline wall impact source includes: on each preset search point, taking any one of the sub-signals as a reference signal, and moving the sub-signals except the reference signal by a distance corresponding to the time difference in a time domain; judging whether the maximum wave crests of a plurality of sub-signals are focused at the same moment on the current preset search point; if so, determining the current preset search point as the position of the impact source of the pressure-bearing pipeline wall.
In a second aspect, an embodiment of the present invention further provides a device for positioning a source of impact on a wall of a pressure-bearing pipeline, the device including: the signal acquisition module is used for acquiring acoustic emission signals generated by impact on the wall of the pressure-bearing pipeline; the filtering module is used for separating a frequency signal with specified frequency from the acoustic emission signal to obtain a waveform envelope spectrum of the acoustic emission signal; the time difference calculation module is used for obtaining the time difference of a plurality of sub-signals reaching a preset search point on the wall of the pressure-bearing pipeline in the acoustic emission signal according to a pre-established pressure-bearing pipeline measurement model and the propagation speed of the acoustic emission signal on the wall of the pressure-bearing pipeline, wherein the propagation speed is obtained through pre-calculation; and the impact source determining module is used for moving the plurality of sub-signals on the time domain according to the time difference, searching a preset searching point, and determining the preset searching point focused by the wave crests of the plurality of sub-signals as the position of the pressure-bearing pipeline wall impact source.
In a third aspect, the embodiment of the present invention further provides a positioning system for a pressure-bearing pipeline wall impact source, which includes a processor and a sensor; the positioning device of the pressure-bearing pipeline wall impact source is arranged in the processor; the sensor is arranged on the wall of the pressure-bearing pipeline.
In a fourth aspect, an embodiment of the present invention further provides a positioning device for a pipeline surface sensor, where the device includes a half-circular-arc-shaped sliding positioning chuck, and an inner diameter of the chuck corresponds to an outer diameter of a pipeline; two bayonets are respectively arranged at two ends of the diameter line and used for placing sensors; two photoelectric sensors are arranged at the top end of the device and are respectively used for transmitting and receiving signals.
The embodiment of the invention has the following beneficial effects:
the embodiment of the invention provides a method, a device and a system for positioning a pressure-bearing pipeline wall impact source; after acoustic emission signals generated by impact on the wall of the pressure-bearing pipeline are collected, frequency signals with specified frequency are separated from the acoustic emission signals, and a waveform envelope spectrum of the acoustic emission signals is obtained; according to a pre-established pressure-bearing pipeline measurement model and the propagation speed of the acoustic emission signal on the wall of the pressure-bearing pipeline, the time difference of a plurality of sub-signals in the acoustic emission signal reaching a preset search point on the wall of the pressure-bearing pipeline can be obtained; and moving the plurality of sub-signals on a time domain according to the time difference so as to search a preset search point, and finally determining the preset search point focused by the wave crests of the plurality of sub-signals as the position of the pressure-bearing pipeline wall impact source. The method improves the accuracy of positioning the impact source of the pressure-bearing pipeline wall.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the invention as set forth above.
In order to make the aforementioned and other objects, features and advantages of the present invention comprehensible, preferred embodiments accompanied with figures are described in detail below.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a schematic flow chart of a method for positioning a pressure-bearing pipeline wall impact source according to an embodiment of the present invention;
FIG. 2 is a schematic flow chart of another method for locating a source of impact on a wall of a pressurized pipeline according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of the location of sensors on the wall of a pressure-bearing conduit according to an embodiment of the present invention;
FIG. 4 is an assembly diagram of a positioning device and a pipe of a dedicated pipe surface sensor according to an embodiment of the present invention;
FIG. 5 is a schematic view of an experimental apparatus for measuring wave velocity according to an embodiment of the present invention;
FIG. 6 is a pipeline measurement model provided by an embodiment of the present invention;
FIG. 7 is a graph of raw acoustic emission signals collected by a sensor provided in accordance with an embodiment of the present invention;
FIG. 8 is a time-frequency domain plot of a narrow-band signal of an acoustic emission signal provided by an embodiment of the present invention;
FIG. 9 is a schematic distance diagram of A, B grid points on a pipeline measurement model according to an embodiment of the present invention;
FIG. 10 is a waveform diagram of an acoustic emission signal shifted in time domain to a sound source point according to an embodiment of the present invention;
FIG. 11 is a diagram illustrating the three-dimensional effect of impact localization provided by an embodiment of the present invention;
FIG. 12 is a flowchart of an algorithm for searching for an impact source according to an embodiment of the present invention;
FIG. 13 is a schematic structural diagram of an alternative positioning device for a source of impact against a wall of a pressurized conduit provided in accordance with an embodiment of the present invention;
FIG. 14 is a schematic structural diagram of a positioning system for a source of impact against a wall of a pressurized pipeline provided by an embodiment of the present invention.
Detailed Description
To make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The method, the device and the system for positioning the impact source of the pressure-bearing pipeline wall can be applied to positioning the impact source of the pressure-bearing pipeline wall and other pressure-bearing facilities. For the understanding of the present embodiment, a detailed description will be given of a method for positioning a pressure-bearing pipeline wall impact source disclosed in the present embodiment.
Referring to fig. 1, a schematic flow chart of a method for locating a source of impact on a wall of a pressure-bearing pipeline is shown, the method comprising:
and S100, collecting acoustic emission signals generated by impact on the wall of the pressure-bearing pipeline.
The phenomenon that local sources in the material rapidly release energy to generate transient elastic waves is called acoustic emission. After the pressure-bearing pipeline wall is impacted, an acoustic emission signal can be generated; the time domain waveform of the acoustic emission impact signal of the pipeline wall is used as an analysis target, so that the impact process can be better analyzed and an impact source can be better positioned. Acoustic emission signals are typically collected using a sensor and an acoustic emission signal collection system and transmitted to a signal processing system, such as a computer.
Step S102, separating a frequency signal with specified frequency from the acoustic emission signal to obtain a waveform envelope spectrum of the acoustic emission signal.
The acoustic emission stress wave (namely the acoustic emission signal) has various time domain characteristics and is synthesized by various frequency signals; according to the physical process generated by impact and the acoustic emission stress wave propagation characteristics, acoustic emission type waves which are reasonably selected and analyzed have great influence on the accuracy of a positioning result, and low-frequency narrow-band signals of acoustic emission signals are generally adopted as the most direct and important analysis targets according to the existing experience. The above process is also referred to as preprocessing of the acoustic emission signal, in order to obtain bending waves (belonging to low-frequency narrowband signals) of the acoustic emission signal. The preprocessing comprises amplification, filtering and the like, so that the positioning precision can be improved, and the probability of pseudo positioning is reduced; meanwhile, a time domain waveform envelope signal is obtained by using a waveform envelope method, so that the influence of other acoustic emission type waves on a positioning result is reduced.
And step S104, obtaining the time difference of a plurality of sub-signals in the acoustic emission signal reaching a preset search point on the wall of the pressure-bearing pipeline according to the pre-established pressure-bearing pipeline measurement model and the propagation speed of the acoustic emission signal on the wall of the pressure-bearing pipeline, wherein the propagation speed is obtained through pre-calculation.
Specifically, the pressure-bearing pipeline measurement model can be established by software through actual measurement data, and a 3D (3 dimensional) model of the pipeline can be established through actual pipeline parameters. And determining a region to be searched of the impact source in the 3D model according to the position of the sensor arranged on the wall of the pressure-bearing pipeline. And (4) dividing the area to be searched into grids to obtain preset search points. And calculating the distance between the preset search point and each sensor, and calculating the time difference of the signals received by each sensor according to the propagation speed of the acoustic emission signals.
And S106, moving the plurality of sub-signals in a time domain according to the time difference, searching preset search points, and determining the preset search points focused by the wave crests of the plurality of sub-signals as the positions of the pressure-bearing pipeline wall impact sources.
Specifically, according to the calculated time difference, the acoustic emission signals received by each sensor are moved in the time domain by a corresponding time difference. If the preset search point is the impact source, the peak value of each acoustic emission signal is focused, and the synthesized signal is maximum, so that the impact source is positioned.
The embodiment of the invention provides a method for positioning a pressure-bearing pipeline wall impact source; after acoustic emission signals generated by impact on the wall of the pressure-bearing pipeline are collected, frequency signals with specified frequency are separated from the acoustic emission signals, and a waveform envelope spectrum of the acoustic emission signals is obtained; according to a pre-established pressure-bearing pipeline measurement model and the propagation speed of the acoustic emission signal on the wall of the pressure-bearing pipeline, the time difference of a plurality of sub-signals in the acoustic emission signal reaching a preset search point on the wall of the pressure-bearing pipeline can be obtained; and moving the plurality of sub-signals on a time domain according to the time difference so as to search a preset search point, and finally determining the preset search point focused by the wave crests of the plurality of sub-signals as the position of the pressure-bearing pipeline wall impact source. The method improves the accuracy of positioning the impact source of the pressure-bearing pipeline wall.
Referring to fig. 2, a schematic flow chart of another method for locating a source of impact on a wall of a pressurized pipeline is shown, which is implemented on the basis of the method shown in fig. 1, and comprises the following steps:
and S200, establishing a pressure-bearing pipeline measurement model according to the position of the sensor arranged on the wall of the pressure-bearing pipeline.
Arranging a plurality of sensors on the wall of the pressure-bearing pipeline, and taking a region surrounded by the sensors as a monitoring region; six sensors may be provided so that four of the sensors define a rectangular area and two of the sensors are respectively located at the centers of the rectangular areas at the two ends of the pipe. And then establishing a model of the pressure-bearing pipeline by using software according to parameters such as the position of the sensor, the radius of the pressure-bearing pipeline and the like, and determining the position and the range of the monitoring area.
And S202, dividing grids on the pipeline wall of the pressure-bearing pipeline measurement model, and determining grid line intersections as preset search points.
Meshing the monitoring area in the model; wherein the spacing of the grid is related to the measurement accuracy; and taking the intersection points of the grids as preset search points of a preset impact source, establishing coordinates, and marking the coordinates.
Step S204, collecting acoustic emission signals through a plurality of sensors arranged on the wall of the pressure-bearing pipeline; wherein each sensor collects a corresponding sub-signal. Due to the different distances between different sensors and the impact source, there is usually a certain time difference between the received corresponding sub-signals. The device comprises six sensors arranged on the wall of a pressure-bearing pipeline, wherein the four sensors which surround a rectangular region are used for acquiring sub-signals, and the other two sensors are respectively positioned at the centers of the rectangular regions at two ends of the pipeline and are used for determining the direction of an impact source in the following process.
Step S206, extracting bending wave signals in the acoustic emission signals;
and S208, calculating the envelope of the waveform of the bending wave signal component by adopting a Hilbert time domain waveform envelope method to obtain a low-frequency narrow-band acoustic emission signal corresponding to the acoustic emission signal.
The phenomena of frequency dispersion and modal aliasing existing in the process of acoustic emission signal propagation generally select the bending wave time domain waveform of an impact acoustic emission signal as the most direct research target, so that the acoustic emission signal processing is simplified; and simultaneously, determining factors influencing the impact positioning precision according to the physical process generated by impact and the acoustic emission stress wave propagation characteristics. And (3) calculating an envelope spectrum of the damage acoustic emission signal by adopting a Hilbert time-domain envelope method, filtering useless acoustic emission stress waves in the signal, and highlighting a narrow-band acoustic emission signal of a bending wave for participating in subsequent positioning process analysis, so as to reduce the interference of other component signals on a positioning result.
The Hilbert transform is mathematically defined: given a real-valued function x (t), whose Hilbert is transformed into x' (t), then:
thus, for a bending wave signal:
S(t)＝A(t)cos[ω(t)+θ(t)]
where ω t is the signal bandwidth, then the Hilbert transform of S (t) is:
S'(t)＝A(t)sin[ω(t)+θ(t)]
from the properties of the trigonometric function, one can derive:
in the formula, | a (t) | is the waveform envelope spectrum of the bending wave.
Step S210, calculating the distance between any two grid line intersection points on the pipeline wall;
the distance between any two points A and B on the pipeline wall can be calculated according to the following expression:
in the formula: (theta)1，z1)、(θ2，z2) Respectively, polar coordinates of a and B, and a is the pipe radius.
Step S212, calculating the time difference of a plurality of sub-signals in the acoustic emission signal reaching each grid line intersection according to the distance and the propagation speed of the acoustic emission signal on the wall of the pressure-bearing pipeline; the shortest propagation path between two points is solved by the distance formula described above.
Specifically, the propagation speed of the acoustic emission signal on the wall of the pressure-bearing pipeline is obtained by the following steps: respectively acquiring sub-signals through two sensors; identifying the time difference of the corresponding sub-signals of the two sensors in a cross-correlation mode; and calculating the propagation speed through a speed distance formula according to the distance between the two sensors and the time difference. Specifically, the propagation velocity is calculated by the following formula: v ═ d (d)2-d1) A,/Δ t; wherein d is1The distance between the first sensor and a preset sound emission source; d2The distance between the second sensor and the sound emission source; at is the difference in time between the arrival of the acoustic emission signal at the first sensor and the second sensor from the acoustic emission source.
In practical application, a wave velocity determination experiment is generally designed to carry out wave velocity measurement. The method comprises the steps of arranging a pair of piezoelectric sensors on the surface of a pipeline, obtaining the time difference of signals reaching the two sensors through a cross-correlation technology, calculating the real propagation speed of the single-mode damage acoustic emission signals on the wall of the pipeline according to the speed formula, and correcting the wave speed according to the theoretical speed of actual pipeline materials.
Step S214, at each preset search point, using any one of the plurality of sub-signals as a reference signal, and moving the sub-signals other than the reference signal by a distance corresponding to the time difference in the time domain.
Step S216, judging whether the maximum wave crests of a plurality of sub-signals are focused at the same moment on the current preset search point;
and step S218, if yes, determining the current preset search point as the position of the impact source of the pressure-bearing pipeline wall.
In practical application, the position of the impact source of the pressure-bearing pipeline wall can be displayed in the form of a damage scattering image.
The method comprises the steps of positioning the impact of the pressure-bearing pipeline wall based on the time domain waveform analysis of an acoustic emission signal, extracting a narrow-band signal with specific frequency components from the impact acoustic emission signal, and obtaining the wave velocity through actual measurement and calculation; and moving the acoustic emission signals received by different sensors on a time domain to form multi-signal focusing, so as to determine the impact position. The method overcomes the frequency dispersion phenomenon of the acoustic emission signal in the transmission process, and effectively solves the problem of false positioning; the method is applied to the surface of the wall of the pressure-bearing pipeline, the research object is expanded from a plane to a curved surface for the first time, and the problems of difficult modeling and poor positioning accuracy are solved.
The embodiment of the invention also provides another positioning method of the pressure-bearing pipeline wall impact source, which is realized by a sensor, an acoustic emission acquisition system and a computer on the basis of the method shown in figure 1. Wherein, engineering software is installed in the computer to analyze and process the signals. This method will be described by taking a 159mm stainless steel pipe as an example. In actual operation, impact signals are generated on the pipeline wall in a lead core breaking mode, a 0.5mm 2B (2black blackness grade 2) type lead core breaking simulation impact source is selected, the frequency of the generated acoustic emission signals is mainly concentrated at about 150kHz, 4R 15 type acoustic emission sensors are selected for signal acquisition, referring to a sensor position schematic diagram on the pressure-bearing pipeline wall shown in FIG. 3, sensors 1# and 4# are arranged at two ends of the diameter of the pipeline, and the same is true for the sensors 2# and 3 #; the sensors 1# and 2#, 3# and 4# are respectively located on a straight line, so that 4 sensors form a rectangular monitoring area. In order to ensure that the acoustic emission sensors are arranged at the two ends of the diameter of the pipeline, the embodiment also provides a positioning device of the pipeline surface sensor, the device is shown in an assembly drawing of the pipeline as shown in figure 4, the device comprises a semi-circular arc sliding positioning chuck, and the inner diameter of the chuck corresponds to the outer diameter of the pipeline; two bayonets are respectively arranged at two ends of the diameter line and used for placing sensors; two photoelectric sensors are arranged at the top end of the device and are respectively used for transmitting and receiving signals. The inner diameter of the chuck is consistent with the outer diameter of the pipeline, so that the device can be tightly attached to the surface of the pipeline; two photoelectric sensors, one transmitting signal and one receiving signal, which are arranged at the top end of the device can ensure that the sensors are positioned on the bus of the pipeline in pairs. By means of the positioning device, the area surrounded by the four sensors is guaranteed to be a half surface of the pipeline. Because the acoustic emission signal can generate frequency dispersion and modal aliasing in the propagation process, the blind selection of group velocity or the table lookup of the acoustic velocity of the material is not reliable, and therefore, a test is needed to determine the real propagation velocity of the single modal damage acoustic emission signal on the pipeline wall. Referring to the schematic diagram of the wave velocity measurement experimental device shown in fig. 5, two sensors are arranged on the same horizontal line, lead is cut off to generate acoustic emission signals, and after the acoustic emission signals are received by the two sensors, the signals are processed by a preamplifier, transmitted to an acoustic emission collector and then transmitted to a computer for processing and calculation. The sensor close to the sound emission source is sensor A, the sensor B is at the far end, the distance d between the two sensors is constant and is respectively 300mm and 200mm, and the time difference of the signals reaching the sensors A and B is obtained by utilizing a cross-correlation technology. And measuring for multiple times, respectively obtaining the actual propagation speeds of the signals as 5514.91m/s and 5723.64m/s by a speed formula, and averaging the speeds measured in two times to obtain the average speed of about 5619.28 m/s. The experimental parameters and the calculation results when d is 0.3m are shown in table 1.
TABLE 1
When d is 0.2m, the experimental parameters and the calculation results are shown in table 2:
TABLE 2
Further, the impact source of the pipeline wall is positioned by utilizing the propagation speed of the obtained acoustic emission signal.
The system specifically works as follows:
(1) a pipeline measurement model shown in figure 6 is established by a computer according to pipeline parameters, a rectangular area formed by sensors is selected as a monitoring area, the area is divided into grids at equal intervals, the interval of each grid is 1mm, the intersection point between a horizontal line and a vertical line is a scanning point, and coordinates are established.
(2) While the lead is broken, an acoustic emission signal is acquired by an acoustic emission acquisition system and a sensor, see the original acoustic emission signal diagram acquired by the sensor shown in fig. 7.
(3) Signal preprocessing is carried out by a computer: and (3) solving a waveform envelope spectrum of the acoustic emission signal by using Hilbert envelope, filtering out other acoustic emission type waves, and reserving bending waves, wherein the narrow-band signal time-frequency domain diagram of the acoustic emission signal is shown in figure 8.
(4) Searching an impact source point: and calculating the distance between any two grid points on the curved surface of the pipeline by using a computer, such as a distance schematic diagram of A, B two grid points on a pipeline measurement model shown in fig. 9, and calculating the signal arrival time difference by using the measured propagation speed of the acoustic emission signal. The signal collected by one of the sensors is used as a reference, and the other three signals move by corresponding time differences. When the grid point is the sound source point, the four signals arrive at the grid point in the same phase, and the peak is at the same time and is focused together in the time domain. Referring to the waveform diagram of the acoustic emission signal shown in fig. 10, which is shifted to the sound source point in the time domain, that is, with the first sensor (1#) as a reference, the other acoustic emission signals are shifted by corresponding time differences in the time domain, and all the signals arrive at the impact source in the same phase in the time domain, so as to form a focused peak effect diagram. And performing the operation on each grid intersection point, wherein the position of the preset search point of the wave crest focusing of the plurality of sub signals is the position of the pressure-bearing pipeline wall impact source.
In general, the peak value can be expressed on the cloud map as a pixel value, and the position with the darkest color is the position with the largest energy, that is, the position of the impact source. Referring to the impact positioning three-dimensional effect diagram shown in fig. 11, the point with the deepest color in the diagram is the acoustic emission source point, and the coordinates of the point are the coordinates of the impact point. The above operations are performed in Matlab engineering simulation software in the form of an algorithm, and finally the impact source position is displayed. Referring to fig. 12, a flow chart of an algorithm for searching for an impact source point is shown, wherein the algorithm comprises the following steps:
(1) calculating the distance, time delay (i.e. time difference) between the grid points and the sensors;
(2) calculating the focusing energy of the grid point by using the time delay and the acoustic emission signal, and taking the energy value as a pixel value;
(3) storing the pixel values;
(4) judging whether the pixel value is the maximum pixel value;
(5) if so, outputting the coordinates of the grid point, namely the acoustic emission source point (impact source point); and if not, performing the operations of the steps (1) - (4) for the next adjacent grid point.
In the experiment, in order to verify the accuracy of the positioning method, ten groups of experiments are carried out on different breakpoints, the actual impact source coordinate is compared with the positioning result of the waveform analysis method, and the experimental result and the calculated radial error are shown in table 3.
TABLE 3
As shown in Table 3, the actual impact coordinate points of the 10 sets of positioning experiment results are compared with the positioning coordinates of the method, the positioning error can be controlled within 15mm, and the accuracy and the feasibility of the pressure-bearing pipeline wall impact positioning method based on acoustic emission signal time domain waveform analysis are verified.
An embodiment of the present invention further provides a positioning device for a pressure-bearing pipeline wall impact source, referring to a schematic structural diagram of the positioning device for a pressure-bearing pipeline wall impact source shown in fig. 13, where the positioning device includes: the signal acquisition module 1300 is used for acquiring an acoustic emission signal generated by impact on the wall of the pressure-bearing pipeline; the filtering module 1302 is configured to separate a frequency signal with a specified frequency from the acoustic emission signal to obtain a waveform envelope spectrum of the acoustic emission signal; the time difference calculation module 1304 is used for obtaining the time difference of a plurality of sub-signals in the acoustic emission signal reaching a preset search point on the wall of the pressure-bearing pipeline according to a pre-established pressure-bearing pipeline measurement model and the propagation speed of the acoustic emission signal on the wall of the pressure-bearing pipeline, wherein the propagation speed is obtained through pre-calculation; and the impact source determining module 1306 is configured to move the multiple sub-signals in the time domain according to the time difference, search for a preset search point, and determine a preset search point where peaks of the multiple sub-signals are focused as a position of a pressure-bearing pipeline wall impact source.
The positioning device for the pressure-bearing pipeline wall impact source provided by the embodiment of the invention has the same technical characteristics as the positioning method for the pressure-bearing pipeline wall impact source provided by the embodiment, so that the same technical problems can be solved, and the same technical effect can be achieved.
The embodiment of the present invention further provides a positioning system for a pressure-bearing pipeline wall impact source, referring to the schematic structural diagram of the positioning system for a pressure-bearing pipeline wall impact source shown in fig. 14, the system includes a processor 140 and a sensor 141; the device is arranged in the processor; the sensor is arranged on the wall of the pressure-bearing pipeline.
It can be clearly understood by those skilled in the art that, for convenience and brevity of description, the specific working process of the system described above may refer to the corresponding process in the foregoing method embodiment, and is not described herein again.
The positioning system for the pressure-bearing pipeline wall impact source provided by the embodiment of the invention has the same technical characteristics as the positioning method and the positioning device for the pressure-bearing pipeline wall impact source provided by the embodiment, so that the same technical problems can be solved, and the same technical effect can be achieved.
The computer program product of the method, the apparatus, and the system for positioning a pressure-bearing pipeline wall impact source according to the embodiments of the present invention includes a computer-readable storage medium storing program codes, where instructions included in the program codes may be used to execute the method described in the foregoing method embodiments, and specific implementation may refer to the method embodiments, and will not be described herein again.
In addition, in the description of the embodiments of the present invention, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
Finally, it should be noted that: the above-mentioned embodiments are only specific embodiments of the present invention, which are used for illustrating the technical solutions of the present invention and not for limiting the same, and the protection scope of the present invention is not limited thereto, although the present invention is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: any person skilled in the art can modify or easily conceive the technical solutions described in the foregoing embodiments or equivalent substitutes for some technical features within the technical scope of the present disclosure; such modifications, changes or substitutions do not depart from the spirit and scope of the embodiments of the present invention, and they should be construed as being included therein. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (8)
1. A method of locating a source of impact against a wall of a pipeline, the method comprising:
collecting acoustic emission signals generated by impact on the wall of the pressure-bearing pipeline;
separating a frequency signal with specified frequency from the acoustic emission signal to obtain a waveform envelope spectrum of the acoustic emission signal;
according to a pre-established pressure-bearing pipeline measurement model and the propagation speed of the acoustic emission signal on the pressure-bearing pipeline wall obtained through pre-calculation, the time difference of a plurality of sub-signals in the acoustic emission signal reaching a preset search point on the pressure-bearing pipeline wall is obtained;
moving the plurality of sub-signals on a time domain according to the time difference, searching the preset search point, and determining the preset search point focused by the wave crests of the plurality of sub-signals as the position of a pressure-bearing pipeline wall impact source;
six sensors are arranged on the wall of the pressure-bearing pipeline, wherein the four sensors surround a rectangular region and are used for collecting the sub-signals, and the two sensors are respectively positioned at the centers of the rectangular regions at the two ends of the pipeline and are used for determining the direction of the impact source;
the step of moving the plurality of sub-signals in the time domain according to the time difference, searching the preset search point, and determining the preset search point focused by the plurality of sub-signal wave crests as the position of the pressure-bearing pipeline wall impact source comprises the following steps:
on each preset search point, taking any one of the sub-signals as a reference signal, and moving the sub-signals except the reference signal by a distance corresponding to a time difference in a time domain;
judging whether the maximum wave crests of the sub-signals are focused at the same moment or not at the current preset search point;
if so, determining the current preset search point as the position of the impact source of the pressure-bearing pipeline wall;
wherein, any sub-signal is the sub-signal collected by any one of the four sensors.
2. The method of claim 1, further comprising:
establishing a pressure-bearing pipeline measurement model according to the position of a sensor arranged on the wall of the pressure-bearing pipeline;
and dividing grids on the pipeline wall of the pressure-bearing pipeline measurement model, and determining the grid line intersection points as the preset search points.
3. The method of claim 1, wherein the step of separating the frequency signal of the specified frequency from the acoustic emission signal to obtain a waveform envelope spectrum of the acoustic emission signal comprises:
extracting bending wave signal components in the acoustic emission signals;
and solving the envelope of the waveform of the bending wave signal component by using a Hilbert method to obtain a low-frequency narrow-band acoustic emission signal corresponding to the acoustic emission signal.
4. The method according to claim 1, characterized in that the propagation speed of the acoustic emission signal on the wall of the pressure-bearing pipeline is obtained by:
collecting sub-signals by two of the sensors, respectively;
identifying the time difference of the sub-signals corresponding to the two sensors in a cross-correlation mode;
and calculating the propagation speed through a speed and distance formula according to the distance between the two sensors and the time difference.
5. The method according to claim 2, wherein the step of obtaining the acquisition time difference of a plurality of sub-signals in the acoustic emission signal according to the pre-established pressure-bearing pipeline measurement model and the pre-calculated propagation velocity of the acoustic emission signal on the wall of the pressure-bearing pipeline comprises:
calculating the distance between any two grid line intersection points on the pipeline wall;
and calculating the time difference of a plurality of sub-signals in the acoustic emission signal reaching each grid line intersection according to the distance and the propagation speed.
6. A device for locating the source of a pressure-bearing pipeline wall impact, the device comprising:
the signal acquisition module is used for acquiring acoustic emission signals generated by impact on the wall of the pressure-bearing pipeline;
six sensors are arranged on the wall of the pressure-bearing pipeline, wherein the four sensors surround a rectangular region and are used for collecting sub-signals, and the two sensors are respectively positioned at the centers of the rectangular regions at the two ends of the pipeline and are used for determining the direction of the impact source;
the filtering module is used for separating a frequency signal with specified frequency from the acoustic emission signal to obtain a waveform envelope spectrum of the acoustic emission signal;
the time difference calculation module is used for obtaining the time difference of a plurality of sub-signals in the acoustic emission signal reaching a preset search point on the wall of the pressure-bearing pipeline according to a pre-established pressure-bearing pipeline measurement model and the propagation speed of the acoustic emission signal on the wall of the pressure-bearing pipeline, wherein the propagation speed is obtained through pre-calculation;
the impact source determining module is used for moving the sub signals in the time domain according to the time difference, searching the preset searching points and determining the preset searching points focused by the wave crests of the sub signals as the positions of the pressure-bearing pipeline wall impact sources;
the impact source determining module is configured to move the plurality of sub-signals in the time domain according to the time difference, search the preset search point, and determine the preset search point where the plurality of sub-signal wave crests are focused as the position of the pressure-bearing pipeline wall impact source, and includes:
on each preset search point, taking any one of the sub-signals as a reference signal, and moving the sub-signals except the reference signal by a distance corresponding to a time difference in a time domain;
judging whether the maximum wave crests of the sub-signals are focused at the same moment or not at the current preset search point;
if so, determining the current preset search point as the position of the impact source of the pressure-bearing pipeline wall;
wherein, any sub-signal is the sub-signal collected by any one of the four sensors.
7. A system for locating a source of impact against a wall of a pressure-bearing pipeline, the system comprising a processor and a sensor;
a positioning device for a pressure-bearing pipeline wall impact source as claimed in claim 6 disposed in said processor; the sensor is arranged on the wall of the pressure-bearing pipeline.
8. A positioning device for pipeline surface sensors, wherein the positioning device is assembled in the positioning system for the pressure-bearing pipeline wall impact source of claim 7, the positioning system comprises six sensors, wherein four sensors surround a rectangular region for collecting the sub-signals, and two sensors are respectively positioned in the centers of the rectangular regions at two ends of the pipeline for determining the direction of the impact source; the device comprises a semi-circular arc-shaped sliding positioning chuck, wherein the inner diameter of the chuck corresponds to the outer diameter of the pipeline; two bayonets are respectively arranged at two ends of the diameter line and used for placing sensors; two photoelectric sensors are arranged at the top end of the device and are respectively used for transmitting and receiving signals;
the two photoelectric sensors are used for positioning four sensors in a positioning system of the pressure-bearing pipeline wall impact source, so that a region surrounded by the four sensors is a half surface of the pipeline.
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| CN115406778B (en) * | 2022-08-29 | 2024-05-10 | 中国空气动力研究与发展中心超高速空气动力研究所 | Method for positioning damage position of grid line take-up area |
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