CN113566124A - Method, device and equipment for selecting optimal excitation frequency of ultrasonic guided wave and storage medium - Google Patents
Method, device and equipment for selecting optimal excitation frequency of ultrasonic guided wave and storage medium Download PDFInfo
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Abstract
The invention discloses a method, a device, equipment and a storage medium for selecting the optimal excitation frequency of ultrasonic guided waves, wherein the method is applied to the ultrasonic guided wave detection of a polyurea anti-corrosion pipeline and comprises the following steps: constructing a polyurea anti-corrosion pipeline simulation model; selecting the frequency range of L (0,2) longitudinal waves in a non-frequency dispersion section as an optional range of the optimal excitation frequency according to a frequency dispersion curve of ultrasonic guided wave propagation in the polyurea anti-corrosion pipeline; loading L (0,2) longitudinal waves under different excitation frequencies in the bare pipe and the polyurea anti-corrosion pipeline simulation model respectively, carrying out data average processing on signals collected by a receiving end, and acquiring time-course curves of the L (0,2) longitudinal waves under different frequencies in a certain time period in the bare pipe and the polyurea anti-corrosion pipeline simulation model; and (4) selecting the optimal excitation frequency in combination with attenuation characteristic analysis. The method can effectively identify and position weak defects with different damage degrees in the polyurea anti-corrosion pipeline, and simultaneously shows the feasibility of realizing detection by utilizing an ultrasonic guided wave detection technology in the polyurea anti-corrosion pipeline.
Description
Technical Field
The invention relates to an ultrasonic guided wave detection technology, in particular to a method, a device and a system for selecting an optimal excitation frequency of an ultrasonic guided wave and a storage medium, and belongs to the technical field of nondestructive detection.
Background
At present, the domestic buried pipelines are mostly applied to the transportation industries of natural gas, petrochemical gas, petroleum, municipal sewage and the like. Due to long-term use and deep underground burying, the outer surface layer of the pipeline is particularly easy to corrode under the influence of underground complex environmental factors, so that the pipe wall becomes thin or cracks occur to cause safety accidents such as gas or liquid leakage and the like. Therefore, it is very important to select a proper corrosion-resistant pipeline and effectively detect the pipeline.
With the continuous updating and development of various types of anticorrosive materials in recent years, the traditional viscoelastic anticorrosive coatings, such as asphalt, epoxy coal asphalt, sintered epoxy powder and the like, no longer meet the current anticorrosive performance requirements, and polyurea coatings are favored as novel anticorrosive materials developed in recent years, with the advantages of excellent corrosion resistance, good physical properties, high curing speed, no pollution to the environment, insensitivity to temperature and humidity and the like.
In fact, the detection means of the anti-corrosion pipeline mostly adopts an ultrasonic guided wave nondestructive detection technology, low-frequency torsional waves or longitudinal waves are excited, the low-frequency torsional waves or longitudinal waves can be transmitted for a long distance along the waveguide, and the attenuation degree of signal energy is small; secondly, the sound field of the ultrasonic guided wave can be distributed on the pipe wall of the whole pipeline, the detection sensitivity to the cracking caused by corrosion in the pipeline is higher, and the ultrasonic guided wave pipe joint has the advantages of convenience, reliability, economy and the like, and can realize the nondestructive detection of the long-distance pipeline.
When the ultrasonic guided waves are longitudinally transmitted along the pipeline, the L (0,2) mode has larger vibration axial displacement, and the identification sensitivity of the ultrasonic guided waves to circumferential defects in the pipeline is higher; meanwhile, the method has the advantages of high propagation speed, high signal exciting and receiving efficiency and the like, and is suitable for detection of long-distance pipelines.
In the process of detecting the polyurea anti-corrosion pipeline by using the ultrasonic guided wave, proper excitation frequency needs to be selected. Therefore, the analysis of the propagation characteristics of the ultrasonic guided waves in the polyurea anti-corrosion pipeline is indispensable, meanwhile, the absorption of the viscoelastic anti-corrosion layer to the energy of the guided waves needs to be considered, the attenuation rule of the guided waves propagating in the polyurea anti-corrosion pipeline is combined, the optimal excitation frequency can be selected more quickly and effectively by means of finite element simulation analysis, and the detection efficiency is improved.
Disclosure of Invention
In view of the above, the invention provides a method, a device, a system, computer equipment and a storage medium for selecting an optimal excitation frequency of ultrasonic guided wave, which can effectively identify and locate weak defects with different damage degrees in a polyurea anti-corrosion pipeline, and simultaneously show feasibility of detection realized by using an ultrasonic guided wave detection technology in the polyurea anti-corrosion pipeline.
The invention aims to provide a method for selecting the optimal excitation frequency of ultrasonic guided waves.
The second purpose of the invention is to provide an ultrasonic guided wave optimal excitation frequency selection device.
It is a third object of the invention to provide a computer apparatus.
It is a fourth object of the present invention to provide a computer-readable storage medium.
The first purpose of the invention can be achieved by adopting the following technical scheme:
an ultrasonic guided wave optimal excitation frequency selection method is applied to ultrasonic guided wave detection of a polyurea anti-corrosion pipeline and comprises the following steps:
constructing a polyurea anti-corrosion pipeline simulation model;
defining the frequency range of L (0,2) longitudinal waves in a non-dispersive section as an optional range of the optimal excitation frequency according to a dispersive curve of ultrasonic guided wave propagation in the polyurea anti-corrosion pipeline;
loading L (0,2) longitudinal waves under different excitation frequencies in the bare pipe and the polyurea anti-corrosion pipeline simulation model respectively, carrying out data average processing on signals collected by a receiving end, and acquiring time-course curves of the L (0,2) longitudinal waves under different frequencies in a certain time period in the bare pipe and the polyurea anti-corrosion pipeline simulation model;
and (3) selecting the optimal excitation frequency by combining the attenuation characteristic analysis of L (0,2) longitudinal waves in the bare pipe and polyurea anti-corrosion pipeline simulation models.
Further, the constructing of the polyurea anti-corrosion pipeline simulation model specifically includes:
analyzing the analytical model of the polyurea anti-corrosion pipeline, judging that the polyurea anti-corrosion pipeline is approximate to an isotropic viscoelastic-elastic material double-layer cylinder ideal structure, and assuming that a contact surface between a viscoelastic polyurea anti-corrosion layer and the elastic pipeline is tightly combined and does not generate any relative displacement;
selecting a three-dimensional entity unit as an elastic pipeline, and setting the corresponding material density, Young modulus and Poisson ratio of the elastic pipeline, wherein the material of the elastic pipeline is a steel pipe or a copper pipe;
selecting a two-dimensional shell unit as a viscoelastic polyurea anticorrosive layer, and setting the corresponding material density, Young modulus, Poisson ratio and viscoelasticity of the viscoelastic polyurea anticorrosive layer;
according to the relation between the surface stress and the displacement boundary condition of each layer in the polyurea anti-corrosion pipeline, the outer surface of the elastic pipeline and the inner surface of the viscoelastic polyurea anti-corrosion layer are provided with a mutual contact pair, and the surface-to-surface constraint binding treatment is carried out;
local anticorrosive coating is peeled off within a certain range from the port of the polyurea anticorrosive pipeline, and meanwhile, a receiving end is arranged at the same position of the excitation end.
Further, the relationship between the surface stress and the displacement boundary condition of each layer in the polyurea anti-corrosion pipeline is as follows:
inner surface of pipe at r ═ a:
the interface between the outer surface of the pipeline and the inner surface of the corrosion protection layer at the position where r is b:
and r is the outer surface of the anticorrosive layer at c:
wherein σrzAnd σrrRespectively representing tangential stress and normal stress; u. ofzAnd urRepresenting tangential and normal displacement fields, respectively; e. v represents the elastic pipe and the viscoelastic polyurea anticorrosive layer respectively.
Further, the pair of the elastic pipe outer surface and the viscoelastic polyurea anticorrosive layer inner surface which are mutually contacted is defined as tangential behavior and normal behavior, wherein the friction formula of the tangential behavior is set to be rough, and the pressure interference of the normal behavior is defaulted to be hard contact.
Furthermore, when the outer surface of the elastic pipeline and the inner surface of the viscoelastic polyurea anticorrosive layer are in mutual contact, the elastic pipeline and the viscoelastic polyurea anticorrosive layer are arranged one by one according to the division zones, the elastic pipeline is taken as a main surface, and the viscoelastic anticorrosive layer is taken as a secondary surface; the 'motion contact method' is selected by the calculation of a mechanical formula, and then a contact algorithm is corrected according to dynamics; the slip formula selects "limited slip";
and when the constraint binding processing of the surfaces is carried out, the surfaces are arranged one by one according to the division partitions, so that the relative displacement of each node on the two surfaces is kept consistent.
Further, loading L (0,2) longitudinal waves under different excitation frequencies in the bare pipe and the polyurea anti-corrosion pipeline simulation model respectively specifically includes:
and applying circumferential load longitudinally along the bare pipe and the polyurea anti-corrosion pipeline simulation model in a surface loading mode to simulate signal loading of L (0,2) longitudinal waves under different excitation frequencies.
Further, the method combines the attenuation characteristic analysis of the L (0,2) longitudinal wave in the bare pipe and polyurea anti-corrosion pipeline simulation model to select the optimal excitation frequency, and specifically comprises the following steps:
according to the attenuation characteristics of L (0,2) longitudinal waves in the bare pipe and polyurea anti-corrosion pipeline simulation model, the calculation formula of the attenuation value and the attenuation coefficient is obtained as follows:
wherein, i is 1, and 2 respectively represents that L (0,2) longitudinal waves are propagated in the simulation models of the bare pipe and the polyurea anti-corrosion pipeline; a. the1Is the peak value of the excitation end signal; a. the2Is half of the peak value of the first time end face echo signal; alpha is the attenuation coefficient of L (0,2) longitudinal wave when passing through the polyurea anti-corrosion pipeline simulation model; l is the length of the pipeline;
obtaining an attenuation rule of L (0,2) longitudinal waves propagating in the bare pipe and the polyurea anti-corrosion pipeline simulation model under different frequencies and a variation trend of the attenuation coefficient when the L (0,2) longitudinal waves pass through the polyurea anti-corrosion pipeline by calculating the attenuation value and the attenuation coefficient;
and taking the excitation frequency corresponding to the lowest attenuation value and attenuation coefficient when the L (0,2) longitudinal wave passes through the polyurea anti-corrosion pipeline simulation model as the optimal excitation frequency.
The second purpose of the invention can be achieved by adopting the following technical scheme:
the utility model provides a device is selected to best excitation frequency of supersound guided wave, is applied to anticorrosive pipeline supersound guided wave of polyurea and detects, the device includes:
the construction module is used for constructing a polyurea anti-corrosion pipeline simulation model;
the defining module is used for defining the frequency range of L (0,2) longitudinal waves in a non-frequency dispersion section as the selectable range of the optimal excitation frequency according to a frequency dispersion curve of ultrasonic guided wave propagation in the polyurea anti-corrosion pipeline;
the loading module is used for loading L (0,2) longitudinal waves under different excitation frequencies in the bare pipe and the polyurea anti-corrosion pipeline simulation model respectively, carrying out data average processing on signals collected by the receiving end and obtaining time-course curves of the L (0,2) longitudinal waves under different frequencies in the bare pipe and the polyurea anti-corrosion pipeline simulation model within a certain time length;
and the selection module is used for selecting the optimal excitation frequency by combining the attenuation characteristic analysis of the L (0,2) longitudinal wave in the bare pipe and polyurea anti-corrosion pipeline simulation model.
The third purpose of the invention can be achieved by adopting the following technical scheme:
the computer equipment comprises a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program stored in the memory to realize the ultrasonic guided wave optimal excitation frequency selection method.
The fourth purpose of the invention can be achieved by adopting the following technical scheme:
a computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method for selecting the optimal excitation frequency of the ultrasonic guided wave is implemented.
Compared with the prior art, the invention has the following beneficial effects:
1. aiming at the problem of excitation frequency selection during ultrasonic guided wave detection in the polyurea anti-corrosion pipeline, the invention provides a method for further selecting proper excitation frequency by analyzing a finite element simulation model and combining the attenuation rule of ultrasonic guided wave propagation in the polyurea anti-corrosion pipeline, which is favorable for improving the visual visibility of detection signals.
2. The invention is beneficial to early predicting the detection effect by constructing an effective simulation analysis model, and provides a useful guiding direction and reference value for the ultrasonic guided wave detection of the polyurea anti-corrosion pipeline in practice.
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, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.
Fig. 1 is a simple flowchart of an ultrasonic guided wave optimal excitation frequency selection method according to embodiment 1 of the present invention.
Fig. 2 is a detailed flowchart of an ultrasonic guided wave optimal excitation frequency selection method according to embodiment 1 of the present invention.
Fig. 3 is a three-dimensional model structure view of the polyurea anti-corrosion pipeline in embodiment 1 of the present invention.
Fig. 4 is a side view structural diagram of a model of the polyurea anti-corrosion pipe in embodiment 1 of the present invention.
Fig. 5a to 5b are dispersion curve diagrams of ultrasonic guided waves in the polyurea anti-corrosion pipeline in embodiment 1 of the invention.
Fig. 6 is a graph showing the attenuation law of L (0,2) longitudinal waves propagated in a simulation model of a bare pipe and a polyurea anti-corrosion pipeline in example 1 of the present invention.
FIG. 7 is a graph showing the variation tendency of the attenuation coefficient of the L (0,2) longitudinal wave of example 1 of the present invention when passing through the polyurea anticorrosive pipeline.
Fig. 8 is a schematic structural diagram of a polyurea anti-corrosion pipeline defect positioning system in embodiment 2 of the invention.
Fig. 9a to 9d are time-course curves of crack detection of the polyurea anti-corrosion pipeline with different circumferential lengths by the 65kHz L (0,2) longitudinal wave in example 2 of the invention.
Fig. 10 is a block diagram of a structure of an ultrasonic guided wave optimal excitation frequency selection apparatus according to embodiment 3 of the present invention.
Fig. 11 is a block diagram of a computer device according to embodiment 4 of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer and more complete, the technical solutions in the embodiments of the present invention will be described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments, and all other embodiments obtained by a person of ordinary skill in the art without creative efforts based on the embodiments of the present invention belong to the protection scope of the present invention.
Example 1:
as shown in fig. 1 and fig. 2, the embodiment provides an optimal excitation frequency selection method for ultrasonic guided wave, which is applied to ultrasonic guided wave detection of a polyurea corrosion-resistant pipeline, and includes the following steps:
s201, constructing a polyurea anti-corrosion pipeline simulation model.
Further, the step S201 specifically includes:
s2011, by analyzing an analytic model of the polyurea anti-corrosion pipeline, judging that the polyurea anti-corrosion pipeline is approximate to an isotropic viscoelastic-elastic material double-layer cylinder ideal structure, and assuming that a contact surface between a viscoelastic polyurea anti-corrosion layer and an elastic pipeline is tightly combined and does not generate any relative displacement.
S2012, selecting the three-dimensional solid unit as an elastic pipeline, and setting the material density, Young modulus and Poisson ratio corresponding to the elastic pipeline.
The elastic pipeline is made of a steel pipe or a copper pipe, the steel pipe is adopted in the embodiment, and the specification and model of the steel pipe is DN80 (namely the outer diameter is 89mm, and the wall thickness is 4 mm); the length of the tube is 3 m; the density is 7850kg/m3The elastic modulus was 206GPa and the Poisson's ratio was 0.33.
The elastic pipeline is a three-dimensional solid unit, the section of the elastic pipeline is divided into 32-36 equal division units along the circumferential direction, in the embodiment, the number of the equal division units is 34, the unit type is C3D8, and the elastic pipeline is divided into two layers along the radial direction, so that the accuracy of a calculation result is improved.
S2013, selecting the two-dimensional shell unit as a viscoelastic polyurea anticorrosive layer, and setting material density, Young modulus, Poisson ratio and viscoelasticity corresponding to the viscoelastic polyurea anticorrosive layer.
In order to be distinguished from the elastic pipeline modeling, the viscoelastic polyurea anticorrosive layer selects a shell unit with the thickness of 1mm and the material density of 1100kg/m3The elastic modulus is 1.5GPa, and the Poisson ratio is 0.42; definition of viscoelastic materials in ABAQUS, one can chooseSetting Prony series in a defined time domain. The Prony number of the polyurea material is set as follows:
TABLE 1 Prony number of stages set for polyurea materials
The viscoelastic polyurea anticorrosive layer is divided into single-layer units along the radial direction by two-dimensional shell units, and the unit type is S4; after the grids are divided by sweeping, the lengths of the grid units of the elastic pipeline and the viscoelastic polyurea anticorrosive layer are both 8 mm.
And (3) setting an analysis step, namely combining two entity models through 'assembly', creating the analysis step, selecting a 'power and display' mode, and setting the calculation time to be 2.5 ms.
S2014, according to the relation between the surface stress and the displacement boundary condition of each layer in the polyurea anti-corrosion pipeline, mutually contacting pairs are arranged on the outer surface of the elastic pipeline and the inner surface of the viscoelastic polyurea anti-corrosion layer, and surface-to-surface constraint binding treatment is carried out.
Considering the influence of the anticorrosive coating on the longitudinal mode guided wave propagation in the pipeline, the radial component and the axial component of the vector potential are both zero, so the relationship between the surface stress and the displacement boundary condition of each layer in the polyurea anticorrosive pipeline is as follows:
inner surface of pipe at r ═ a:
the interface between the outer surface of the pipeline and the inner surface of the corrosion protection layer at the position where r is b:
and r is the outer surface of the anticorrosive layer at c:
wherein σrzAnd σrrRespectively representing tangential stress and normal stress; u. ofzAnd urRepresenting tangential and normal displacement fields, respectively; e. v represents the elastic pipe and the viscoelastic polyurea anticorrosive layer respectively.
According to the relationship between the surface stress and the displacement boundary condition of each layer in the polyurea anti-corrosion pipeline, in finite element simulation, a mutual contact pair needs to be arranged on the outer surface of the elastic pipeline and the inner surface of the viscoelastic anti-corrosion layer, mainly the definition of tangential behavior and normal behavior is carried out, wherein the friction formula of the tangential behavior is set to be rough; the pressure interference of the normal behavior is defaulted to be hard contact, and the fact that the normal pressure can be transmitted only when the outer surface of the elastic pipeline and the inner surface of the viscoelastic anticorrosive layer are in a close contact state is ensured.
Setting the outer surface of the elastic pipeline and the inner surface of the viscoelastic polyurea anticorrosive layer to be contacted with each other for time synchronization, and setting the elastic pipeline as a main surface and the viscoelastic anticorrosive layer as a secondary surface one by one according to the division; the 'motion contact method' is selected by the calculation of a mechanical formula, and then a contact algorithm is corrected according to dynamics; the slip formula selects "limited slip".
At the moment, the outer surface of the elastic pipeline and the inner surface of the viscoelastic anticorrosive layer still slide, surface-to-surface constraint binding treatment is required, and when surface-to-surface binding is set, the nodes are set one by one according to division, so that the relative displacement of each node on the two surfaces is kept consistent.
S2015, stripping a local anticorrosive layer within a certain range from the port of the polyurea anticorrosive pipeline, and meanwhile, arranging a receiving end at the same position of the excitation end.
Because the elastic pipeline and the viscoelastic anticorrosive coating are different in material property and far different in acoustic characteristic impedance, the local anticorrosive coating is peeled within a certain range from the pipeline port, the local anticorrosive coating is peeled within a range about 55mm wide from the pipeline port, and meanwhile, the ring surface is arranged at the same position of the excitation end to serve as a receiving end.
The model of the finally established polyurea corrosion-proof pipeline is shown in fig. 3 and 4.
S202, defining the frequency range of L (0,2) longitudinal waves in a non-frequency dispersion section as an optional range of the optimal excitation frequency according to a frequency dispersion curve of ultrasonic guided wave propagation in the polyurea anti-corrosion pipeline.
As shown in fig. 5a to 5b, the selectable range of the excitation frequency is defined based on the dispersion curve of the ultrasonic guided wave propagation in the polyurea anti-corrosive pipeline, and the excitation frequency is 50kHz, 55kHz, 60kHz, 65kHz, 70kHz and 75kHz respectively.
S203, loading L (0,2) longitudinal waves under different excitation frequencies in the bare pipe and the polyurea anti-corrosion pipeline simulation model respectively, carrying out data average processing on signals collected by the receiving end, and obtaining time-course curves of the L (0,2) longitudinal waves under different frequencies in the bare pipe and the polyurea anti-corrosion pipeline simulation model within a certain time.
The method comprises the following steps of loading L (0,2) longitudinal waves under different excitation frequencies in a bare pipe simulation model and a polyurea anti-corrosion pipeline simulation model respectively, wherein the L longitudinal waves are as follows: and applying circumferential load longitudinally along the bare pipe and the polyurea anti-corrosion pipeline simulation model in a surface loading mode to simulate signal loading of L (0,2) longitudinal waves under different excitation frequencies.
The excitation signals are all sine signals with 10 cycles modulated by cosine functions, and the expression of the signal function is as follows:
wherein f iscIs the center frequency of the excitation signal; n is the selected number of cycles.
And S204, selecting the optimal excitation frequency by combining the attenuation characteristic analysis of L (0,2) longitudinal waves in the bare pipe and polyurea anti-corrosion pipeline simulation model.
After time-course curves of L (0,2) longitudinal waves propagating in a bare pipe and a polyurea anti-corrosion pipeline under different frequencies within a certain time are obtained, in combination with the attenuation characteristic aspect of guided waves, a calculation formula of an attenuation value and an attenuation coefficient of guided wave energy under the same frequency condition is required:
wherein, i is 1, and 2 respectively represents that L (0,2) longitudinal waves are propagated in the simulation models of the bare pipe and the polyurea anti-corrosion pipeline; a. the1Is the peak value of the excitation end signal; a. the2Is half of the peak value of the first time end face echo signal; alpha is the attenuation coefficient of L (0,2) longitudinal wave when passing through the polyurea anti-corrosion pipeline simulation model; l is the length of the pipeline.
The calculation results are shown in table 2 below.
TABLE 2 attenuation of guided waves of different frequencies propagating in bare pipes and polyurea corrosion-resistant pipes
Through calculating the attenuation value and the attenuation coefficient, the attenuation rule (attenuation value change) of the L (0,2) longitudinal wave propagating in the bare pipe and the polyurea anti-corrosion pipeline simulation model under different frequencies and the change trend of the attenuation coefficient of the L (0,2) longitudinal wave when passing through the polyurea anti-corrosion pipeline are obtained, as shown in fig. 6 and 7, through the attenuation condition of the L (0,2) longitudinal wave in the polyurea anti-corrosion pipeline, it can be seen that the attenuation value and the attenuation coefficient of the L (0,2) longitudinal wave under a certain excitation frequency condition are reduced to be the lowest when passing through the polyurea anti-corrosion pipeline, which indicates that the energy attenuation degree of the longitudinal wave under the condition is the lowest, the attenuation rate is the slowest, and the corresponding excitation frequency can be used as the optimal excitation frequency reference value.
Example 2:
the embodiment provides a defect positioning simulation analysis method applied to different damage degrees in a polyurea anti-corrosion pipeline, an adopted polyurea anti-corrosion pipeline defect positioning system is shown in fig. 8, and the specific implementation process is as follows:
s1: based on the simulation model of the polyurea anti-corrosion pipeline in the embodiment 1, circumferential cracks with different section loss rates are arranged at a position 1.2m away from the signal excitation end, as shown in fig. 9a to 9d (a is complete and lossless, b is the circumferential length of the crack pi/6, c is the circumferential length of the complete crack pi/5, and d is the circumferential length of the complete crack pi/4), the widths are all 2mm, and the depths are all 3 mm. The circumferential crack defects were set as in table 3 below.
TABLE 3 setting of circumferential crack Defect
S2: according to the loading mode described in the embodiment 1, the optimal excitation frequency is loaded to obtain a time course curve of the defect detection of the L (0,2) longitudinal wave in the polyurea anti-corrosion pipeline under the optimal excitation frequency.
And S3, identifying and positioning the defect position of the polyurea anti-corrosion pipeline. And identifying the defects, positioning and comparing errors by utilizing the moments corresponding to the maximum values of the amplitudes of the incident waves, the defect echoes and the end face echoes in the time-course curve, wherein the error percentage is specifically calculated as follows:
wherein, T1、T2、T3The time corresponding to the maximum value of the amplitude of the incident wave, the defect echo and the end face echo in each working condition time-course curve is obtained; t is t2The defect signal time obtained by calculation; l iscThe distance between the defect of the polyurea anti-corrosion pipeline and the excitation end; l is the length of the polyurea anti-corrosion pipeline; e is the error percentage. The defect positioning error percentages of the polyurea anti-corrosion pipeline under different working conditions are shown in the following table 4.
TABLE 4 Defect location error percentages for different working conditions of polyurea anti-corrosion pipelines
Example 3:
as shown in fig. 10, the present embodiment provides an ultrasonic guided wave optimal excitation frequency selection apparatus, which is applied to ultrasonic guided wave detection of a polyurea anti-corrosion pipeline, and includes a construction module 1001, a defining module 1002, a loading module 1003, and a selection module 1004, where specific functions of each module are as follows:
the building module 1001 is used for building a polyurea anti-corrosion pipeline simulation model.
The defining module 1002 is configured to define a frequency range of the L (0,2) longitudinal wave in the non-frequency dispersion section as an optional range of the optimal excitation frequency based on a frequency dispersion curve of ultrasonic guided wave propagation in the polyurea anti-corrosion pipeline.
The loading module 1003 is configured to load L (0,2) longitudinal waves at different excitation frequencies in the bare pipe and the polyurea anti-corrosion pipeline simulation model respectively, perform data averaging processing on the signals collected by the receiving end, and obtain a time-course curve of the L (0,2) longitudinal waves propagating in the bare pipe and the polyurea anti-corrosion pipeline simulation model at different frequencies within a certain time period.
And the selecting module 1004 is used for selecting the optimal excitation frequency in combination with the attenuation characteristic analysis of the L (0,2) longitudinal wave in the bare pipe and polyurea anti-corrosion pipeline simulation model.
It should be noted that the system provided in this embodiment is only illustrated by the division of the functional modules, and in practical applications, the functions may be distributed by different functional modules according to needs, that is, the internal structure is divided into different functional modules to complete all or part of the functions described above.
Example 4:
as shown in fig. 11, the present embodiment provides a computer device, which is a computer and includes a processor 1102, a memory, an input device 1103, a display device 1104 and a network interface 1105 connected by a system bus 1101, wherein the processor is used for providing computing and control capabilities, the memory includes a nonvolatile storage medium 1106 and an internal memory 1107, the nonvolatile storage medium 1106 stores an operating system, a computer program and a database, the internal memory 1107 provides an environment for the operation of the operating system and the computer program in the nonvolatile storage medium, and when the processor 1102 executes the computer program stored in the memory, the method for selecting an optimal excitation frequency of an ultrasound guided wave according to embodiment 1 above is implemented as follows:
constructing a polyurea anti-corrosion pipeline simulation model;
defining the frequency range of L (0,2) longitudinal waves in a non-dispersive section as an optional range of the optimal excitation frequency according to a dispersive curve of ultrasonic guided wave propagation in the polyurea anti-corrosion pipeline;
loading L (0,2) longitudinal waves under different excitation frequencies in the bare pipe and the polyurea anti-corrosion pipeline simulation model respectively, carrying out data average processing on signals collected by a receiving end, and acquiring time-course curves of the L (0,2) longitudinal waves under different frequencies in a certain time period in the bare pipe and the polyurea anti-corrosion pipeline simulation model;
and (3) selecting the optimal excitation frequency by combining the attenuation characteristic analysis of L (0,2) longitudinal waves in the bare pipe and polyurea anti-corrosion pipeline simulation models.
Example 5:
the present embodiment provides a computer-readable storage medium, which stores a computer program, and when the computer program is executed by a processor, the method for selecting an optimal excitation frequency of an ultrasonic guided wave according to embodiment 1 is implemented as follows:
constructing a polyurea anti-corrosion pipeline simulation model;
defining the frequency range of L (0,2) longitudinal waves in a non-dispersive section as an optional range of the optimal excitation frequency according to a dispersive curve of ultrasonic guided wave propagation in the polyurea anti-corrosion pipeline;
loading L (0,2) longitudinal waves under different excitation frequencies in the bare pipe and the polyurea anti-corrosion pipeline simulation model respectively, carrying out data average processing on signals collected by a receiving end, and acquiring time-course curves of the L (0,2) longitudinal waves under different frequencies in a certain time period in the bare pipe and the polyurea anti-corrosion pipeline simulation model;
and (3) selecting the optimal excitation frequency by combining the attenuation characteristic analysis of L (0,2) longitudinal waves in the bare pipe and polyurea anti-corrosion pipeline simulation models.
It should be noted that the computer readable storage medium of the present embodiment may be a computer readable signal medium or a computer readable storage medium or any combination of the two. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the foregoing. More specific examples of the computer readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.
In the present embodiment, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. In this embodiment, however, a computer readable signal medium may include a propagated data signal with a computer readable program embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated data signal may take many forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may also be any computer readable storage medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. The computer program embodied on the computer readable storage medium may be transmitted using any appropriate medium, including but not limited to: electrical wires, optical cables, RF (radio frequency), etc., or any suitable combination of the foregoing.
The computer-readable storage medium may be written with a computer program for performing the present embodiments in one or more programming languages, including an object oriented programming language such as Java, Python, C + +, and conventional procedural programming languages, such as C, or similar programming languages, or combinations thereof. The program may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet service provider).
The flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of methods, apparatus, and computer devices according to various embodiments described above. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions. The modules described in the above embodiments may be implemented by software or hardware.
The foregoing description is only exemplary of the preferred embodiments of the invention and is illustrative of the principles of the technology employed. It will be appreciated by those skilled in the art that the scope of the disclosure in the embodiments described above is not limited to the particular combination of features described above, and that other embodiments can be made by any combination of features described above or their equivalents without departing from the spirit of the disclosure. For example, the above features and (but not limited to) the features with similar functions disclosed in the above embodiments are mutually replaced to form the technical solution.
It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described above, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.
Claims (10)
1. A method for selecting the optimal excitation frequency of ultrasonic guided waves is applied to ultrasonic guided wave detection of a polyurea anti-corrosion pipeline, and is characterized by comprising the following steps:
constructing a polyurea anti-corrosion pipeline simulation model;
defining the frequency range of L (0,2) longitudinal waves in a non-dispersive section as an optional range of the optimal excitation frequency according to a dispersive curve of ultrasonic guided wave propagation in the polyurea anti-corrosion pipeline;
loading L (0,2) longitudinal waves under different excitation frequencies in the bare pipe and the polyurea anti-corrosion pipeline simulation model respectively, carrying out data average processing on signals collected by a receiving end, and acquiring time-course curves of the L (0,2) longitudinal waves under different frequencies in a certain time period in the bare pipe and the polyurea anti-corrosion pipeline simulation model;
and (3) selecting the optimal excitation frequency by combining the attenuation characteristic analysis of L (0,2) longitudinal waves in the bare pipe and polyurea anti-corrosion pipeline simulation models.
2. The method for selecting the optimal excitation frequency of the ultrasonic guided wave according to claim 1, wherein the constructing of the polyurea anti-corrosion pipeline simulation model specifically comprises:
analyzing the analytical model of the polyurea anti-corrosion pipeline, judging that the polyurea anti-corrosion pipeline is approximate to an isotropic viscoelastic-elastic material double-layer cylinder ideal structure, and assuming that a contact surface between a viscoelastic polyurea anti-corrosion layer and the elastic pipeline is tightly combined and does not generate any relative displacement;
selecting a three-dimensional entity unit as an elastic pipeline, and setting the corresponding material density, Young modulus and Poisson ratio of the elastic pipeline, wherein the material of the elastic pipeline is a steel pipe or a copper pipe;
selecting a two-dimensional shell unit as a viscoelastic polyurea anticorrosive layer, and setting the corresponding material density, Young modulus, Poisson ratio and viscoelasticity of the viscoelastic polyurea anticorrosive layer;
according to the relation between the surface stress and the displacement boundary condition of each layer in the polyurea anti-corrosion pipeline, the outer surface of the elastic pipeline and the inner surface of the viscoelastic polyurea anti-corrosion layer are provided with a mutual contact pair, and the surface-to-surface constraint binding treatment is carried out;
local anticorrosive coating is peeled off within a certain range from the port of the polyurea anticorrosive pipeline, and meanwhile, a receiving end is arranged at the same position of the excitation end.
3. The method for selecting the optimal excitation frequency of the ultrasonic guided wave according to claim 2, wherein the relationship between the surface stress and the displacement boundary condition of each layer in the polyurea anti-corrosion pipeline is as follows:
inner surface of pipe at r ═ a:
the interface between the outer surface of the pipeline and the inner surface of the corrosion protection layer at the position where r is b:
and r is the outer surface of the anticorrosive layer at c:
wherein σrzAnd σrrRespectively representing tangential stress and normal stress; u. ofzAnd urRepresenting tangential and normal displacement fields, respectively; e. v represents the elastic pipe and the viscoelastic polyurea anticorrosive layer respectively.
4. The method for selecting the optimal excitation frequency of the ultrasonic guided wave according to claim 2, wherein the pair of the elastic pipe outer surface and the viscoelastic polyurea anticorrosive coating inner surface which are mutually contacted is defined by tangential behavior and normal behavior, wherein the friction formula of the tangential behavior is set to be rough, and the pressure interference of the normal behavior is defaulted to be hard contact.
5. The method for selecting the optimal excitation frequency of the ultrasonic guided wave according to claim 2, wherein when the outer surface of the elastic pipeline and the inner surface of the viscoelastic polyurea anticorrosive coating are in mutual contact, the elastic pipeline and the viscoelastic anticorrosive coating are arranged one by one according to division zones, and the elastic pipeline is taken as a main surface and the viscoelastic anticorrosive coating is taken as a secondary surface; the 'motion contact method' is selected by the calculation of a mechanical formula, and then a contact algorithm is corrected according to dynamics; the slip formula selects "limited slip";
and when the constraint binding processing of the surfaces is carried out, the surfaces are arranged one by one according to the division partitions, so that the relative displacement of each node on the two surfaces is kept consistent.
6. The method for selecting the optimal excitation frequency of the ultrasonic guided wave according to any one of claims 1 to 5, wherein the loading of the L (0,2) longitudinal waves with different excitation frequencies in the simulation models of the bare pipe and the polyurea anti-corrosion pipeline respectively comprises:
and applying circumferential load longitudinally along the bare pipe and the polyurea anti-corrosion pipeline simulation model in a surface loading mode to simulate signal loading of L (0,2) longitudinal waves under different excitation frequencies.
7. The method for selecting the optimal excitation frequency of the ultrasonic guided wave according to any one of claims 1 to 5, wherein the selecting of the optimal excitation frequency in combination with the analysis of the attenuation characteristics of the L (0,2) longitudinal wave in the simulation models of the bare pipe and the polyurea anti-corrosion pipeline specifically comprises:
according to the attenuation characteristics of L (0,2) longitudinal waves in the bare pipe and polyurea anti-corrosion pipeline simulation model, the calculation formula of the attenuation value and the attenuation coefficient is obtained as follows:
wherein, i is 1, and 2 respectively represents that L (0,2) longitudinal waves are propagated in the simulation models of the bare pipe and the polyurea anti-corrosion pipeline; a. the1Is the peak value of the excitation end signal; a. the2Is half of the peak value of the first time end face echo signal; alpha is the attenuation coefficient of L (0,2) longitudinal wave when passing through the polyurea anti-corrosion pipeline simulation model; l is the length of the pipeline;
obtaining an attenuation rule of L (0,2) longitudinal waves propagating in the bare pipe and the polyurea anti-corrosion pipeline simulation model under different frequencies and a variation trend of the attenuation coefficient when the L (0,2) longitudinal waves pass through the polyurea anti-corrosion pipeline by calculating the attenuation value and the attenuation coefficient;
and taking the excitation frequency corresponding to the lowest attenuation value and attenuation coefficient when the L (0,2) longitudinal wave passes through the polyurea anti-corrosion pipeline simulation model as the optimal excitation frequency.
8. The utility model provides a device is selected to best excitation frequency of supersound guided wave, is applied to anticorrosive pipeline supersound guided wave of polyurea and detects which characterized in that, the device includes:
the construction module is used for constructing a polyurea anti-corrosion pipeline simulation model;
the defining module is used for defining the frequency range of L (0,2) longitudinal waves in a non-frequency dispersion section as the selectable range of the optimal excitation frequency according to a frequency dispersion curve of ultrasonic guided wave propagation in the polyurea anti-corrosion pipeline;
the loading module is used for loading L (0,2) longitudinal waves under different excitation frequencies in the bare pipe and the polyurea anti-corrosion pipeline simulation model respectively, carrying out data average processing on signals collected by the receiving end and obtaining time-course curves of the L (0,2) longitudinal waves under different frequencies in the bare pipe and the polyurea anti-corrosion pipeline simulation model within a certain time length;
and the selection module is used for selecting the optimal excitation frequency by combining the attenuation characteristic analysis of the L (0,2) longitudinal wave in the bare pipe and polyurea anti-corrosion pipeline simulation model.
9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, and wherein the processor implements the method for selecting an optimal excitation frequency for guided ultrasound waves according to any one of claims 1 to 7 when executing the computer program stored in the memory.
10. A computer-readable storage medium storing a computer program, wherein the computer program is executed by a processor to implement the method for selecting an optimal excitation frequency for guided ultrasound waves according to any one of claims 1 to 7.
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