CN111189930A - Crack detection method, system and equipment based on pipe body and storage medium - Google Patents
Crack detection method, system and equipment based on pipe body and storage medium Download PDFInfo
- Publication number
- CN111189930A CN111189930A CN202010082651.5A CN202010082651A CN111189930A CN 111189930 A CN111189930 A CN 111189930A CN 202010082651 A CN202010082651 A CN 202010082651A CN 111189930 A CN111189930 A CN 111189930A
- Authority
- CN
- China
- Prior art keywords
- displacement data
- pipe body
- preset
- order
- bending mode
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/44—Processing the detected response signal, e.g. electronic circuits specially adapted therefor
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/44—Processing the detected response signal, e.g. electronic circuits specially adapted therefor
- G01N29/46—Processing the detected response signal, e.g. electronic circuits specially adapted therefor by spectral analysis, e.g. Fourier analysis or wavelet analysis
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/02—Indexing codes associated with the analysed material
- G01N2291/028—Material parameters
- G01N2291/0289—Internal structure, e.g. defects, grain size, texture
Abstract
The embodiment of the invention relates to the technical field of signal processing, and discloses a crack detection method, system, equipment and storage medium based on a pipe body. The embodiment of the invention firstly obtains the vibration displacement data of the pipe body; separating the bending modes of the vibration displacement data based on the vibration amplitude and the phase angle compensation of the bending mode of each order to obtain the separated bending mode of each order; and carrying out crack detection operation on the pipe body according to the separated bending modes of each order. Therefore, when the crack on the pipe body is detected, the single bending mode is separated according to the vibration amplitude and the phase angle compensation of each bending mode, and then the crack detection operation is performed on the basis of the separated bending mode, so that the crack detection accuracy is greatly improved.
Description
Technical Field
The invention relates to the technical field of signal processing, in particular to a crack detection method, a crack detection system, crack detection equipment and a crack detection storage medium based on a pipe body.
Background
With the wide application of the reducing structure barrel, especially the application in oil transportation, train high-speed rail wheel shafts and even weapons and other aspects, the detection behavior of the barrel becomes more and more important.
The reducing structure barrel can also be expressed as a reducing pipe, and the pipe body of the reducing pipe is formed by sequentially connecting pipe sections with different diameters in series.
Conventional pipe inspection methods include conventional ultrasonic inspection, eddy current inspection, radiographic inspection, penetrant inspection, magnetic particle inspection, Charge Coupled Device (CCD) imaging, and the like,
however, these tube body detection means have many drawbacks, and an accurate tube body detection result cannot be obtained. Moreover, the operation is complicated, the use is very inconvenient, and the requirements of in-situ detection and health management on the reducer pipe are difficult to meet.
Different from the conventional pipe body detection means, a relatively novel nondestructive detection method, namely ultrasonic guided wave detection, can be adopted.
When the ultrasonic guided wave detection is implemented, the whole length of the barrel can be covered and the barrel can penetrate through the wall of the barrel only by arranging the annular sensor at one position of the barrel, so that the barrel detection in the whole range is realized.
Therefore, the ultrasonic guided wave detection has the characteristics of high speed, simplicity in operation and comprehensive detection, is hardly influenced by external environments such as fields and weather, does not need any pretreatment on the barrel, and can realize in-situ detection of the barrel.
Obviously, ultrasonic guided wave detection is suitable for real-time and online diagnostic monitoring of the state of the reducer pipe, crack damage of the inner bore and the surface of the barrel can be found in time, and a crack part can be detected and positioned, so that the efficiency of the whole reducer pipe is always in a monitored state, and important basis can be provided for safety, economic use and timely maintenance of the barrel.
More finely, the ultrasonic guided wave detection technology is mainly a linear ultrasonic guided wave detection technology, and the linear ultrasonic guided wave detection technology has higher detection precision and sensitivity for cracks with the size larger than the wavelength, but when the cracks are detected, the detection result is not accurate.
Disclosure of Invention
In order to solve the above problems, embodiments of the present invention provide a method, a system, a device, and a storage medium for detecting a crack based on a pipe body.
In a first aspect, an embodiment of the present invention provides a crack detection method based on a pipe body, including:
acquiring vibration displacement data of the pipe body;
separating the bending modes of the vibration displacement data based on the vibration amplitude and the phase angle compensation of the bending mode of each order to obtain the separated bending mode of each order;
and carrying out crack detection operation on the pipe body according to the separated bending mode of each order.
Preferably, the vibration displacement data of obtaining the body specifically includes:
acquiring current displacement data of the pipe body;
determining a position point where a preset sensor corresponding to the current displacement data is located;
and converting a coordinate system of the current displacement data based on the position point to obtain vibration displacement data.
Preferably, after the obtaining of the vibration displacement data of the pipe body, the crack detection method based on the pipe body further includes:
and removing the axisymmetric mode from the vibration displacement data to obtain new vibration displacement data, and performing the separation of the bending mode on the vibration displacement data based on the vibration amplitude and the phase angle compensation of the bending mode of each order according to the new vibration displacement data to obtain the separated bending mode of each order.
Preferably, the separating the bending modes of the vibration displacement data based on the vibration amplitude and the phase angle compensation of the bending mode of each order to obtain the separated bending mode of each order specifically includes:
analyzing the vibration displacement data to obtain a sinusoidal signal group consisting of bending modes of each order;
determining a current amplitude compensation and a current phase angle compensation in the vibration amplitude according to the set of sinusoidal signals;
determining a separation error according to the current amplitude compensation, the current phase angle compensation, a preset arc length in a preset arc length array and an initial amplitude in a preset mapping relation;
and if the separation error is smaller than a preset error threshold value, determining the sinusoidal signal group as each separated bending mode of each order.
Preferably, after determining a separation error according to the current amplitude compensation, the current phase angle compensation, a preset arc length in a preset arc length array, and an initial amplitude in a preset mapping relationship, the method for detecting a crack based on a pipe body further includes:
if the separation error is larger than the preset error threshold, determining a learning rate according to a preset coefficient, a preset angular frequency, the preset arc length, the current phase angle compensation, the initial amplitude and the current amplitude compensation to obtain a current learning rate;
updating the current amplitude compensation and the current phase angle compensation according to the current learning rate to obtain new amplitude compensation and new phase angle compensation;
and taking the new amplitude compensation as the current amplitude compensation, taking the new phase angle compensation as the current phase angle compensation, and returning to execute the step of determining the separation error according to the current amplitude compensation, the current phase angle compensation, the preset arc length in the preset arc length array and the initial amplitude in the preset mapping relation.
Preferably, before analyzing the vibration displacement data to obtain a set of sinusoidal signals composed of bending modes of each order, the method for detecting cracks on the basis of the pipe body further includes:
acquiring a first mapping relation between a preset arc length array and the vibration displacement data;
and performing discrete Fourier transform on the first mapping relation to obtain a preset mapping relation between the bending mode of each order and the initial amplitude.
Preferably, the pipe body is a reducer pipe, and the crack is a micro-crack;
the bending mode according to every order of separating is to the body carries out crack detection operation, specifically includes:
generating a wave packet diagram of the bending mode according to the vibration amplitude corresponding to the separated bending mode of each order;
determining a first arrival time corresponding to the wave packet map;
performing wavelet transformation on the wave packet diagram to obtain a second arrival time and a current center frequency;
determining a corresponding first group speed according to a preset central frequency in a preset frequency dispersion curve, and determining a corresponding second group speed according to the current central frequency;
and determining the distance of the microcracks corresponding to the microcracks on the reducer pipe according to the first arrival time, the second arrival time, the first group velocity and the second group velocity.
In a second aspect, an embodiment of the present invention provides a crack detection system based on a pipe body, including:
the data receiving module is used for acquiring vibration displacement data of the pipe body;
the mode separation module is used for separating the bending modes of the vibration displacement data based on the vibration amplitude and the phase angle compensation of the bending mode of each order so as to obtain the separated bending mode of each order;
and the crack detection module is used for carrying out crack detection operation on the pipe body according to the separated bending mode of each order.
In a third aspect, an embodiment of the present invention provides an electronic device, which includes a memory, a processor, and a computer program stored on the memory and executable on the processor, where the processor executes the computer program to implement the steps of the method for detecting a crack based on a pipe body according to the first aspect of the present invention.
In a fourth aspect, embodiments of the present invention provide a non-transitory computer-readable storage medium, on which a computer program is stored, where the computer program, when executed by a processor, implements the steps of the method for detecting a crack in a pipe body according to the first aspect of the present invention.
According to the crack detection method, system, equipment and storage medium based on the pipe body provided by the embodiment of the invention, the vibration displacement data of the pipe body is firstly obtained; separating the bending modes of the vibration displacement data based on the vibration amplitude and the phase angle compensation of the bending mode of each order to obtain the separated bending mode of each order; and carrying out crack detection operation on the pipe body according to the separated bending modes of each order. Therefore, when the crack on the pipe body is detected, the single bending mode is separated according to the vibration amplitude and the phase angle compensation of each bending mode, and then the crack detection operation is performed on the basis of the separated bending mode, so that the crack detection accuracy is greatly improved.
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 those skilled in the art can also obtain other drawings according to the drawings without creative efforts.
Fig. 1 is a flowchart of a crack detection method based on a pipe body according to an embodiment of the present invention;
fig. 2 is a flowchart of a crack detection method based on a pipe body according to another embodiment of the present invention;
FIG. 3 is a schematic view of a circumferential arrangement of sensors provided in accordance with a further embodiment of the present invention;
FIG. 4 is a schematic diagram of a coordinate system of a predetermined sensor according to another embodiment of the present invention;
FIG. 5 is a schematic illustration of a multi-section sensor deployment according to yet another embodiment of the present invention;
FIG. 6 is a schematic diagram of vibration displacement data after removing axisymmetric modes according to yet another embodiment of the present invention;
FIG. 7 is a flowchart of a crack detection method based on a pipe body according to still another embodiment of the present invention;
FIG. 8 is a schematic diagram of a first mapping relationship plotted in a two-dimensional rectangular coordinate system according to yet another embodiment of the invention;
FIG. 9 is a schematic diagram of a spectrum according to yet another embodiment of the present invention;
fig. 10 is a schematic structural diagram of a crack detection system based on a pipe body according to an embodiment of the present invention;
fig. 11 is a schematic physical structure diagram of an electronic device according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious 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.
Fig. 1 is a flowchart of a crack detection method based on a pipe body according to an embodiment of the present invention, as shown in fig. 1, the method includes:
and S1, acquiring vibration displacement data of the pipe body.
Taking a conventional linear ultrasonic guided wave detection technology as an example, in view of the fact that a longitudinal mode or torsional mode guided wave can generate an echo signal when encountering a crack, the linear ultrasonic guided wave detection technology mostly adopts a change relation between time and amplitude in the echo signal to detect the crack.
However, the crack detection method has high detection accuracy and sensitivity only for cracks with a size larger than the wavelength, but the detection result is not accurate when the microcracks are detected.
This is because, when the microcracks are detected, the change in the time and amplitude characteristics is not significant, which results in low detection sensitivity and thus inaccurate detection results.
In order to adapt to a crack detection scene for detecting microcracks, the crack detection operation is performed based on the bending mode in the embodiment of the invention, which considers that the guided wave can generate a larger bending mode guided wave when encountering cracks, so that the crack detection operation can be performed based on the bending mode, and thus, the crack detection accuracy is higher.
In a specific implementation, the execution subject of the invention is an electronic device, which may be any computing device, and is not limited to a personal computer or the like.
The vibration displacement data obtained here can be acquired by preset sensors deployed circumferentially on the pipe body. The pipe body one end can set up the excitation source, and this excitation source can be a signal generator, and signal generator can send the guided wave, and the echo of this guided wave can be gathered to the default sensor, and the echo of this guided wave is the vibration displacement data here promptly. Then, the vibration displacement data collected by the preset sensor can be transmitted to the electronic equipment.
And S2, separating the bending modes of the vibration displacement data based on the vibration amplitude and the phase angle compensation of the bending modes of each order to obtain the separated bending modes of each order.
In order to detect a crack in the pipe body, a plurality of bending modes of multiple orders are mixed in the vibration displacement data, and a plurality of individual bending modes included in the vibration displacement data can be separated with reference to a main parameter of the bending modes.
The main parameters of the bending mode are vibration amplitude and phase angle compensation, and each individual bending mode has its own vibration amplitude and phase angle compensation.
And S3, performing crack detection operation on the pipe body according to each separated bending mode of each order.
After the separated bending modes of multiple orders are obtained, crack detection operations may be performed according to the bending modes.
Of course, since the embodiment of the present invention has a good application effect on the reducer pipe and the microcracks, the pipe body in the embodiment of the present invention may be specifically the reducer pipe, and the cracks may be specifically the microcracks, but is not limited thereto. After all, the embodiment of the invention has a better detection effect on general pipe body cracks.
As for the reducer pipe, because the number of the bending mode guided waves is large, each variable cross section and variable diameter surface of the reducer pipe can generate a large number of bending mode echoes and defect echoes which are mixed together, and meanwhile, the propagation characteristics of the bending mode guided waves in the reducer pipe are complex, the conventional ultrasonic guided wave mode separation method such as a time-frequency analysis method and a matching tracking method is difficult to be qualified for the separation operation of the bending mode, and therefore, the embodiment of the invention has outstanding adaptive performance for the application scene of the reducer pipe.
According to the crack detection method based on the pipe body, provided by the embodiment of the invention, the vibration displacement data of the pipe body is firstly obtained; separating the bending modes of the vibration displacement data based on the vibration amplitude and the phase angle compensation of the bending mode of each order to obtain the separated bending mode of each order; and carrying out crack detection operation on the pipe body according to the separated bending modes of each order. Therefore, when the crack on the pipe body is detected, the single bending mode is separated according to the vibration amplitude and the phase angle compensation of each bending mode, and then the crack detection operation is performed on the basis of the separated bending mode, so that the crack detection accuracy is greatly improved.
Fig. 2 is a flowchart of a crack detection method based on a pipe body according to another embodiment of the present invention, which is based on the embodiment shown in fig. 1.
In this embodiment, acquire the vibration displacement data of body, specifically include:
acquiring current displacement data of the pipe body;
determining a position point where a preset sensor corresponding to the current displacement data is located;
and converting a coordinate system of the current displacement data based on the position point to obtain vibration displacement data.
In a specific implementation, in order to acquire vibration displacement data on the pipe body, the excitation source and the preset sensor may be pre-disposed on the pipe body, where the preset sensor may be multiple, for example, the number of the preset sensors on any cross section may be recorded as m, and m may be 64, but is not limited. The preset sensor can be a receiving sensor, can receive echoes of the guided waves, records vibration displacement data of the mixed guided waves when the mixed guided waves pass through the sensor, and the data are changed along with time.
As for a specific deployment mode, if the inlet and the outlet exist in the pipe body, the excitation source can be uniformly deployed in the circumferential direction at any one of the inlet or the outlet, and the excitation source can emit guided waves; next, a predetermined sensor may be circumferentially disposed on a certain cross section of the pipe body, where reference may be made to a circumferential arrangement diagram of the sensor shown in fig. 3, where fig. 3 is illustrated with a certain cross section of the pipe body as a background.
Of course, the default sensors may be deployed at varying cross-sections that will vary per perimeter, i.e., each particular cross-section.
The echo collected at the preset sensor can be recorded as the current displacement data.
In order to facilitate separation of bending modes, vibration displacement data obtained by processing current displacement data can be used as input quantity of separation operation.
The processing operation is specifically described by taking a predetermined sensor of a cross section shown in fig. 3 as an example, and further referring to fig. 4, fig. 4 will be taken as the position point O2The preset sensor of (2) is taken as an example.
With respect to FIG. 4, the predetermined sensor is located in the coordinate system of (R, T, Z), the location point O2The center of circle of the cross section of the pipe body is O1And the coordinate system of the circle center is (X, Y, Z).
It will be appreciated that the location point O2The current displacement data acquired by the preset sensor is substantially based on a circle center coordinate system (X, Y, Z) and is positioned at a determined position point O2Then, the current displacement data can be converted from the circle center coordinate system to the preset sensor O2Under the corresponding coordinate system (R, T, Z). Therefore, the vibration displacement data as the input amount of the separation operation is actually based on the coordinate system corresponding to the preset sensor.
According to the crack detection method based on the pipe body, the collected current displacement data can be converted into the RTZ coordinate system corresponding to each preset sensor, so that subsequent bending mode separation operation is facilitated.
In addition, when the bending mode separation operation is performed, the embodiment of the invention actually mainly uses the vibration displacement data on the R axis in the vibration displacement data.
More specifically, if the pipe body is a reducer pipe, a preset sensor may be circumferentially disposed on each variable cross section of the reducer pipe.
Referring to fig. 5, the preset sensor may be deployed at a varying cross section that will vary at each circumference.
It can be understood that the multi-section sensor arrangement mode improves the data utilization rate, greatly reduces the data processing difficulty, overcomes the insensitivity of the linear ultrasonic guided wave detection to the microcrack, and can accurately identify and position the microcrack in the barrel.
Therefore, the micro-cracks in the reducer pipe can be found in time, the barrel is maintained, the service life is prolonged, the cost is reduced, and the application value is practical.
More specifically, if the pipe body is a reducer pipe, a preset sensor can be deployed at each special section of the reducer pipe, and since the ultrasonic guided waves generate complicated echoes at each reducing position, the echoes will be mixed with the echoes of microcracks in the pipe body.
Wherein, the special section can also be called as a reducing section.
When the crack detection operation is finally carried out, the sensor data corresponding to any one variable diameter section and the sensor data on the next variable diameter section of the variable diameter section can be determined, then, the displacement data transmitted between the two variable diameter sections can be obtained according to the two sensor data, so that the echo generated by variable diameter is removed, only the echo generated by the crack which possibly exists is left, and the crack detection operation is carried out on the variable diameter pipe according to the separated bending mode of each order based on the remaining echo.
On the basis of the foregoing embodiment, preferably, after S1, the method for detecting a crack on the basis of a pipe further includes:
and S11, removing the axisymmetric mode from the vibration displacement data to obtain new vibration displacement data.
S2 is performed based on the new vibration displacement data.
It is understood that the axisymmetric guided wave generates a larger guided wave of bending mode when encountering a crack, and the bending mode is non-axisymmetric.
Therefore, in order to make the crack detection result more accurate, when the bending mode is separated, the unnecessary axisymmetric mode can be removed from the input amount of the separation operation.
The new vibration displacement data refers to vibration displacement data obtained by removing an axisymmetric mode from original vibration displacement data.
As for the removing operation for removing the axisymmetric mode, it may be specifically configured that, considering that the sum of a circle of displacements of the bending mode in the circumferential direction is zero, at any time of any pipe body section, each vibration displacement data may be subtracted from the average value thereof, so that the vibration displacement caused by the axisymmetric mode in the original data may be removed.
The average value is the average value of all vibration displacement data acquired by a circle of preset sensors on the circumferential direction of the cross section of the pipe body.
As for the vibration displacement data after removing the axisymmetric mode, new vibration displacement data can be seen in fig. 6.
And then, separating the bending modes of the new vibration displacement data based on the vibration amplitude and the phase angle compensation of the bending mode of each order to obtain the separated bending mode of each order.
Therefore, by removing the axisymmetric mode, the separation operation efficiency of the bending mode can be higher, and the final crack detection accuracy can be higher.
Fig. 7 is a flowchart of a crack detection method based on a pipe body according to another embodiment of the present invention, which is based on the embodiment shown in fig. 1.
In this embodiment, after removing the axisymmetric mode from the vibration displacement data, wavelet transformation may be performed on the vibration displacement data from which the axisymmetric mode is removed, so as to determine the center frequency and the frequency bandwidth of the vibration displacement data at different times; then, the order number n of possible bending modes can be determined according to the obtained central frequency and frequency bandwidth in the dispersion curve chart, wherein n is a positive integer, and the order is always increased to n from 1.
After determining that n orders exist, the remaining amplitude values except n may be accumulated, and the accumulated value Num may be
Wherein m is the number of initial amplitudes, and m is greater than or equal to n.
Further, the S2 specifically includes:
and S21, analyzing the vibration displacement data to obtain a sinusoidal signal group consisting of bending modes of each order.
In order to separate the bending modes of multiple orders, the vibration displacement data may be regarded as a signal group of sinusoidal signals with different amplitudes and different phases, and the signal group of sinusoidal signals may be denoted as Y, in view of the difference in vibration modes of different orders.
Here, the vibration displacement data may also be referred to as mixed vibration displacement data.
As for the Y, the number of the Y,
y denotes a signal group consisting of n sinusoidal signals of different amplitudes and phases, and a sinusoidal signal can be regarded as a bending mode of one order.
Wherein (A)i+ΔAi) Representing the amplitude of vibration, thetaiRepresenting phase angle compensation, wiThe angular frequency corresponding to the bending mode of the ith order is shown, and i is a serial number; a. theiRepresenting the initial amplitude, Δ AiIndicating amplitude compensation.
The angular frequency and the initial amplitude related in the embodiment of the present invention may be obtained in advance, and are not limited herein.
And S22, determining the current amplitude compensation and the current phase angle compensation in the vibration amplitude according to the sinusoidal signal group.
The current amplitude compensation Delta A in the sinusoidal signal group can be analyzediAnd current phase angle compensation thetai。
Wherein the content of the first and second substances,
and S23, determining a separation error according to the current amplitude compensation, the current phase angle compensation, the preset arc length in the preset arc length array and the initial amplitude in the preset mapping relation.
Then, a separation error can be determined, and whether the separation operation can be finished is judged according to the error value of the separation error.
As to the manner of determination of the separation error, Δ A may be compensated for based on the current amplitudeiCurrent phase angle compensation thetaiAnd determining the preset arc length in the preset arc length array and the initial amplitude in the preset mapping relation.
Wherein, the preset arc length array can be recorded as x ═ x1,x2,x3,…,xm]And m represents the number of preset arc lengths. For the predetermined arc length, if it is a certain valueFor example, based on a circle of a certain cross section, a position point where a preset sensor is located on the circle is selected as a starting point, and then a rotation direction is selected, for example, a clockwise direction is selected as the rotation direction; then, the rotation can be carried out from the starting point in the clockwise direction, the arc length distance between the first preset sensor and the starting point is the preset arc length, and the other preset arc lengths are analogized.
Therefore, the preset sensors at different positions on the circumference respectively correspond to different arc length distances, so that a preset arc length array is constructed.
As for the determination method of the separation error, a determination method may be adopted, that is, the separation error is determined by a preset error model according to the current amplitude compensation, the current phase angle compensation, the preset arc length in the preset arc length array and the initial amplitude in the preset mapping relationship. The predetermined error model may be denoted as e (x), specifically,
where e (X) denotes a separation error, and the set X includes a current amplitude compensation and a current phase angle compensation, which may be denoted as X ═ Δ a1,ΔA2,…,ΔAn-1,θ1,θ2,…,θn]；AiRepresenting the initial amplitude, wiRepresenting the angular frequency, x, corresponding to the bending mode of the ith orderjRepresents the preset arc length in the preset arc length array, ur _ f (x)j) Representing vibration displacement data corresponding to a preset arc length.
And S24, if the separation error is smaller than a preset error threshold value, determining the sinusoidal signal group as each separated bending mode of each order.
After the separation error is determined, if the separation error is smaller than a preset error threshold epsilon with a smaller value, the separation of the bending modes of each order can be considered to be successful, and the current sinusoidal signal group is used as a determined bending mode group.
According to the crack detection method based on the pipe body, provided by the embodiment of the invention, the bending guided waves of each order in the reducer pipe can be accurately separated through amplitude compensation and phase angle compensation of the guided waves, so that the subsequent crack detection operation is facilitated.
On the basis of the foregoing embodiment, preferably, after S23, the method for detecting a crack on the basis of a pipe further includes:
and S241, if the separation error is larger than the preset error threshold, determining a learning rate according to a preset coefficient, a preset angular frequency, the preset arc length, the current phase angle compensation, the initial amplitude and the current amplitude compensation to obtain a current learning rate.
It is understood that if the separation error is greater than the predetermined error threshold epsilon, a learning rate can be determined, and the amplitude compensation and the phase angle compensation can be continuously adjusted according to the learning rate to achieve a lower error level.
Among them, the learning rate can be written as LR.
In a specific implementation, in order to determine the real-time learning rate, the learning rate can be determined by using a preset learning rate formula, such as a preset coefficient, a preset angular frequency, a preset arc length, a current phase angle compensation, an initial amplitude value and a current amplitude value compensation,
where LR represents the current learning rate, CjDenotes a predetermined coefficient, wiThe angular frequency corresponding to the bending mode of the ith order is also denoted as the predetermined angular frequency, xjRepresenting a predetermined arc length, θ, in an array of predetermined arc lengthsnRepresenting the current phase angle compensation, AiRepresenting the initial amplitude, Δ AiIndicating the current amplitude compensation.
Wherein, (2n-1) × 1 represents the dimension corresponding to the parenthesis content in the preset learning rate formula.
Here, a coefficient determination formula of the preset coefficient may be given,
wherein the parameters can be referred to above and are not described herein.
And S242, updating the current amplitude compensation and the current phase angle compensation according to the current learning rate to obtain new amplitude compensation and new phase angle compensation.
Then, compensation adjustment can be performed according to the current learning rate LR.
A specific type of adjustment can be given, as follows,
X＝X-βLR，
the set X comprises amplitude compensation and phase angle compensation, β is a compensation coefficient, the set X on the left side of the equal sign represents new amplitude compensation and new phase angle compensation, and the set X on the right side represents current amplitude compensation and current phase angle compensation.
And S243, taking the new amplitude compensation as the current amplitude compensation, and taking the new phase angle compensation as the current phase angle compensation.
After S243, execution returns to S23.
Therefore, after the values of the amplitude compensation and the phase angle compensation are re-adjusted, the separation error can be re-calculated through the adjusted amplitude compensation and phase angle compensation. By such a cyclic adjustment, the separation error can be kept at a low level.
And finally, the amplitude compensation and the phase angle compensation of the determined sinusoidal signal group are finally adjusted.
In addition, if the separation error is equal to the preset error threshold, the separation is considered to be successful and the operation is ended, or the separation is considered to be unsuccessful and the next cycle adjustment of amplitude compensation and phase angle compensation is performed.
On the basis of the foregoing embodiment, before analyzing the vibration displacement data to obtain a set of sinusoidal signals composed of bending modes of each order, the method for detecting cracks on the basis of a pipe body preferably further includes:
acquiring a first mapping relation between a preset arc length array and the vibration displacement data;
and performing discrete Fourier transform on the first mapping relation to obtain a preset mapping relation between the bending mode of each order and the initial amplitude.
It can be understood that the vibration amplitude (A) of the bending mode of each orderi+ΔAi) May include an initial amplitude aiAnd amplitude compensation Δ AiThe embodiments of the invention described above relate primarily to amplitude compensation Δ AiDetermination of (A), the initial amplitude A will be discussed primarily hereiniAnd (4) determining.
In a specific implementation, a preset arc length array x may be obtained first, and then a first mapping relation between the preset arc length array and the vibration displacement data ur _ f (x) is drawn in a two-dimensional rectangular coordinate system; and then carrying out discrete Fourier transform on the first mapping relation to obtain a frequency amplitude diagram.
A schematic diagram of the first mapping relation plotted in the two-dimensional rectangular coordinate system can be seen in fig. 8.
The spectrogram can be seen in fig. 9.
The abscissa in the spectrogram is a bending mode of one order corresponding to each discrete point, and the ordinate is a corresponding initial amplitude value which can be recorded as
A＝[A1,A2,…,An,An+1,…,Am]，
As can be seen, the data content displayed in the spectrogram is a preset mapping relationship between the bending mode of each order and the initial amplitude.
On the basis of the above embodiment, preferably, the pipe body is a reducer pipe, and the crack is a micro-crack;
the bending mode according to every order of separating is to the body carries out crack detection operation, specifically includes:
generating a wave packet diagram of the bending mode according to the vibration amplitude corresponding to the separated bending mode of each order;
determining a first arrival time corresponding to the wave packet map;
performing wavelet transformation on the wave packet diagram to obtain a second arrival time and a current center frequency;
determining a corresponding first group speed according to a preset central frequency in a preset frequency dispersion curve, and determining a corresponding second group speed according to the current central frequency;
and determining the distance of the microcracks corresponding to the microcracks on the reducer pipe according to the first arrival time, the second arrival time, the first group velocity and the second group velocity.
It will be appreciated that in order to obtain accurate crack detection information, the orientation of the crack in the pipe body may be calculated.
Specifically, the embodiment of the present invention may be described by taking the microcracks on the reducer pipe as an example.
For example, if the bending modes of the respective orders in the vibration displacement data in the mixed state are completely separated for any time, the vibration amplitude (a) can be usedi+ΔAi) And obtaining a wave packet image of the time-varying bending mode guided waves of different orders.
Taking the wave packet diagram of the bending mode of any order as an example, the target wave packet therein can be determined, so as to obtain the arrival time thereof, and the arrival time is recorded as a first arrival time t1(ii) a Then, wavelet transformation can be carried out on the wave packet map, so that the maximum amplitude point of the corresponding wave packet position area is determined, the arrival time and the center frequency are further obtained, and the obtained arrival time can be recorded as second arrival time t2The center frequency obtained at this time can be recorded as the current center frequency f2(ii) a Then, the predetermined center frequency can be mapped to a predetermined dispersion curve of the excitation mode and the order bending mode to obtain a first group velocity v1(ii) a The current center frequency f can be adjusted2Corresponding to the preset dispersion curve to obtain a second group velocity v2。
The determination method for determining the target wave packet may be that, in the embodiment of the present invention, a cross section of a pipe body where the excitation source and the preset sensor are disposed may be denoted as P ═ P1,P2,…,Pp]Total p sections. First, the whole operation described in the embodiment of the present invention can be performed on a crack-free reducer to obtain a wave packet diagram. At this timeAny one of the sections PiIn the wave packet diagram obtained above, the first wave packet must meet the pth of the order modei+1The sections are back.
If the reference group is used as the reference group, when any cracked reducer pipe is detected, after the wave packet image is obtained, the wave packet returned from the next section corresponding to the reference group can be found, and all wave packets before the wave packet are returned from the crack in the pipe body.
As for the test data of the crack-free reducer pipe as the control group, it can be obtained by a real measurement method or a finite element simulation method.
Wherein the center frequency f is preset1The obtaining mode of the method may be that the excitation source may excite a longitudinal mode or a torsional mode in the barrel by using the signal modulated by the window function, and the center frequency of the guided wave excited by the excitation source may be recorded as the preset center frequency.
For example, the excitation source may excite a torsional mode T (0, 1) in the barrel using a signal having a center frequency of 20kHz modulated by a Hanning window function.
Then, the first arrival time, the second arrival time, the first group velocity and the second group velocity are used for determining the distance of the microcracks corresponding to the microcracks on the reducer pipe through a preset distance determination formula,
wherein d represents the crack distance, which is the microcrack distance herein, so that the axial distance of the preset sensor corresponding to the microcrack distance is represented, and other parameters are referred to above and are not described herein.
For the calculation of the crack distance, one can be cited here.
Specifically, taking the wave packet diagram of the bending mode of any order as an example, the target wave packet can be found out from the wave packet diagram, so as to obtain the first arrival time t11.363 ms; then, wavelet transform can be carried out on the wave packet image, the maximum amplitude point of the corresponding wave packet position area is found, and second arrival time t is obtained21.35ms and the current center frequency f220 kHz; then, the preset central frequency is corresponding to the preset dispersion curve of the excitation mode and the order bending mode to obtain a first group velocity v13245 m/s; the current center frequency f can be adjusted2Corresponding to the preset dispersion curve to obtain a second group velocity v22832m/s, the calculated d may be 2051.3 mm. This value can be compared to a standard value of 2000mm, clearly the error of this value to a standard value of 2000mm is 2.57%, within a reasonable range.
Therefore, the embodiment of the invention can perform crack detection operation on the pipe body according to the separated bending mode of each order so as to obtain more accurate crack detection information, wherein the crack detection information can be specifically the crack distance. Therefore, the axial position of the microcrack in the pipe body can be determined by using the amplitude information.
Fig. 10 is a schematic structural diagram of a crack detection system based on a pipe body according to an embodiment of the present invention, and as shown in fig. 10, the system includes: a data receiving module 301, a mode separation module 302 and a crack detection module 303;
the data receiving module 301 is configured to obtain vibration displacement data of the pipe body;
a mode separation module 302, configured to separate the bending modes of the vibration displacement data based on the vibration amplitude and the phase angle compensation of the bending mode of each order, so as to obtain a separated bending mode of each order;
and the crack detection module 303 is configured to perform a crack detection operation on the pipe body according to the separated bending mode of each order.
According to the crack detection system based on the pipe body, provided by the embodiment of the invention, the vibration displacement data of the pipe body is firstly obtained; separating the bending modes of the vibration displacement data based on the vibration amplitude and the phase angle compensation of the bending mode of each order to obtain the separated bending mode of each order; and carrying out crack detection operation on the pipe body according to the separated bending modes of each order. Therefore, when the crack on the pipe body is detected, the single bending mode is separated according to the vibration amplitude and the phase angle compensation of each bending mode, and then the crack detection operation is performed on the basis of the separated bending mode, so that the crack detection accuracy is greatly improved.
The system embodiment provided in the embodiments of the present invention is for implementing the above method embodiments, and for details of the process and the details, reference is made to the above method embodiments, which are not described herein again.
Fig. 11 is a schematic entity structure diagram of an electronic device according to an embodiment of the present invention, and as shown in fig. 11, the electronic device may include: a processor (processor)401, a communication Interface (communication Interface)402, a memory (memory)403 and a bus 404, wherein the processor 401, the communication Interface 402 and the memory 403 complete communication with each other through the bus 404. The communication interface 402 may be used for information transfer of an electronic device. Processor 401 may call logic instructions in memory 403 to perform a method comprising:
acquiring vibration displacement data of the pipe body;
separating the bending modes of the vibration displacement data based on the vibration amplitude and the phase angle compensation of the bending mode of each order to obtain the separated bending mode of each order;
and carrying out crack detection operation on the pipe body according to the separated bending mode of each order.
In addition, the logic instructions in the memory 403 may be implemented in the form of software functional units and stored in a computer readable storage medium when the software functional units are sold or used as independent products. 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 above-described method 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 another aspect, an embodiment of the present invention further provides a non-transitory computer-readable storage medium, on which a computer program is stored, where the computer program is implemented by a processor to perform the method provided by the foregoing embodiments, for example, including:
acquiring vibration displacement data of the pipe body;
separating the bending modes of the vibration displacement data based on the vibration amplitude and the phase angle compensation of the bending mode of each order to obtain the separated bending mode of each order;
and carrying out crack detection operation on the pipe body according to the separated bending mode of each order.
The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the embodiments or some parts of the embodiments.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. A crack detection method based on a pipe body is characterized by comprising the following steps:
acquiring vibration displacement data of the pipe body;
separating the bending modes of the vibration displacement data based on the vibration amplitude and the phase angle compensation of the bending mode of each order to obtain the separated bending mode of each order;
and carrying out crack detection operation on the pipe body according to the separated bending mode of each order.
2. The method for detecting the crack based on the pipe body according to claim 1, wherein the obtaining of the vibration displacement data of the pipe body specifically comprises:
acquiring current displacement data of the pipe body;
determining a position point where a preset sensor corresponding to the current displacement data is located;
and converting a coordinate system of the current displacement data based on the position point to obtain vibration displacement data.
3. The pipe body-based crack detection method according to claim 1, wherein after the obtaining of the vibration displacement data of the pipe body, the pipe body-based crack detection method further comprises:
and removing the axisymmetric mode from the vibration displacement data to obtain new vibration displacement data, and performing the separation of the bending mode on the vibration displacement data based on the vibration amplitude and the phase angle compensation of the bending mode of each order according to the new vibration displacement data to obtain the separated bending mode of each order.
4. The method for detecting cracks in a tubular body according to claim 1, wherein the separating of the bending modes from the vibration displacement data based on the vibration amplitude and the phase angle compensation of the bending mode of each order to obtain the separated bending mode of each order specifically comprises:
analyzing the vibration displacement data to obtain a sinusoidal signal group consisting of bending modes of each order;
determining a current amplitude compensation and a current phase angle compensation in the vibration amplitude according to the set of sinusoidal signals;
determining a separation error according to the current amplitude compensation, the current phase angle compensation, a preset arc length in a preset arc length array and an initial amplitude in a preset mapping relation;
and if the separation error is smaller than a preset error threshold value, determining the sinusoidal signal group as each separated bending mode of each order.
5. The method of claim 4, wherein after determining the separation error according to the current amplitude compensation, the current phase angle compensation, the preset arc length in the preset arc length array, and the initial amplitude in the preset mapping relationship, the method further comprises:
if the separation error is larger than the preset error threshold, determining a learning rate according to a preset coefficient, a preset angular frequency, the preset arc length, the current phase angle compensation, the initial amplitude and the current amplitude compensation to obtain a current learning rate;
updating the current amplitude compensation and the current phase angle compensation according to the current learning rate to obtain new amplitude compensation and new phase angle compensation;
and taking the new amplitude compensation as the current amplitude compensation, taking the new phase angle compensation as the current phase angle compensation, and returning to execute the step of determining the separation error according to the current amplitude compensation, the current phase angle compensation, the preset arc length in the preset arc length array and the initial amplitude in the preset mapping relation.
6. The tubular body based crack detection method of claim 4, wherein prior to analyzing the vibrational displacement data to obtain the set of sinusoidal signals comprising bending modes of each order, the tubular body based crack detection method further comprises:
acquiring a first mapping relation between a preset arc length array and the vibration displacement data;
and performing discrete Fourier transform on the first mapping relation to obtain a preset mapping relation between the bending mode of each order and the initial amplitude.
7. The method for detecting cracks on a pipe body according to any one of claims 1 to 6, wherein the pipe body is a reducer pipe, and the cracks are microcracks;
the bending mode according to every order of separating is to the body carries out crack detection operation, specifically includes:
generating a wave packet diagram of the bending mode according to the vibration amplitude corresponding to the separated bending mode of each order;
determining a first arrival time corresponding to the wave packet map;
performing wavelet transformation on the wave packet diagram to obtain a second arrival time and a current center frequency;
determining a corresponding first group speed according to a preset central frequency in a preset frequency dispersion curve, and determining a corresponding second group speed according to the current central frequency;
and determining the distance of the microcracks corresponding to the microcracks on the reducer pipe according to the first arrival time, the second arrival time, the first group velocity and the second group velocity.
8. A crack detection system based on a pipe body, comprising:
the data receiving module is used for acquiring vibration displacement data of the pipe body;
the mode separation module is used for separating the bending modes of the vibration displacement data based on the vibration amplitude and the phase angle compensation of the bending mode of each order so as to obtain the separated bending mode of each order;
and the crack detection module is used for carrying out crack detection operation on the pipe body according to the separated bending mode of each order.
9. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor when executing the program performs the steps of the method of any of claims 1 to 7.
10. A non-transitory computer readable storage medium having stored thereon a computer program, wherein the computer program when executed by a processor implements the steps of the method of any of claims 1 to 7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010082651.5A CN111189930B (en) | 2020-02-07 | 2020-02-07 | Crack detection method, system and equipment based on pipe body and storage medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010082651.5A CN111189930B (en) | 2020-02-07 | 2020-02-07 | Crack detection method, system and equipment based on pipe body and storage medium |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111189930A true CN111189930A (en) | 2020-05-22 |
| CN111189930B CN111189930B (en) | 2022-07-19 |
Family
ID=70708369
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010082651.5A Active CN111189930B (en) | 2020-02-07 | 2020-02-07 | Crack detection method, system and equipment based on pipe body and storage medium |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111189930B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112326805A (en) * | 2021-01-04 | 2021-02-05 | 湖南久钰电子有限公司 | Tunnel dome online monitoring method and system, electronic equipment and storage medium |
| CN115657599A (en) * | 2022-12-28 | 2023-01-31 | 歌尔股份有限公司 | Laser cutting compensation method, device and equipment and storage medium |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60214228A (en) * | 1984-03-21 | 1985-10-26 | ジヨン・モーレイ | Vibration analyzing method |
| WO1989009399A1 (en) * | 1988-03-30 | 1989-10-05 | Juha Ylitalo | An imaging method |
| CN102226783A (en) * | 2011-03-25 | 2011-10-26 | 北京工业大学 | Device and method for detecting pipeline closed cracks based on vibro-acoustic modulation technology |
| CN104833729A (en) * | 2015-05-05 | 2015-08-12 | 北京工业大学 | Ultrasonic guided-wave based calculation method for separating flexural mode reflected signal |
| CN110470742A (en) * | 2019-04-25 | 2019-11-19 | 西安交通大学 | A kind of accurate detecting method of channel bend defect |
-
2020
- 2020-02-07 CN CN202010082651.5A patent/CN111189930B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60214228A (en) * | 1984-03-21 | 1985-10-26 | ジヨン・モーレイ | Vibration analyzing method |
| WO1989009399A1 (en) * | 1988-03-30 | 1989-10-05 | Juha Ylitalo | An imaging method |
| CN102226783A (en) * | 2011-03-25 | 2011-10-26 | 北京工业大学 | Device and method for detecting pipeline closed cracks based on vibro-acoustic modulation technology |
| CN104833729A (en) * | 2015-05-05 | 2015-08-12 | 北京工业大学 | Ultrasonic guided-wave based calculation method for separating flexural mode reflected signal |
| CN110470742A (en) * | 2019-04-25 | 2019-11-19 | 西安交通大学 | A kind of accurate detecting method of channel bend defect |
Non-Patent Citations (1)
| Title |
|---|
| 陈乐 等: "弯曲导波模态分离与频散补偿研究", 《中国测试》 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112326805A (en) * | 2021-01-04 | 2021-02-05 | 湖南久钰电子有限公司 | Tunnel dome online monitoring method and system, electronic equipment and storage medium |
| CN112326805B (en) * | 2021-01-04 | 2021-04-13 | 湖南久钰电子有限公司 | Tunnel dome online monitoring method and system, electronic equipment and storage medium |
| CN115657599A (en) * | 2022-12-28 | 2023-01-31 | 歌尔股份有限公司 | Laser cutting compensation method, device and equipment and storage medium |
| CN115657599B (en) * | 2022-12-28 | 2023-02-28 | 歌尔股份有限公司 | Laser cutting compensation method, device, equipment and storage medium |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111189930B (en) | 2022-07-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104819766B (en) | Based on it is humorous make an uproar than envelope demodulation frequency band determine method | |
| CN111189930B (en) | Crack detection method, system and equipment based on pipe body and storage medium | |
| CN102636303B (en) | Method for measuring residual stress of thin plating layer based on surface ultrasonic waves | |
| CN108459087B (en) | Multimode Lamb wave mode separation method applied to plate structure damage detection | |
| CN102590341B (en) | Method for detecting sonic time and tracking phase wave band of concrete pile shaft by ultrasonic transmission method | |
| CN104748704A (en) | Thin-walled structure ultrasonic resonance thickness measurement frequency spectrum analysis interpolation correction method | |
| CN110057918B (en) | Method and system for quantitatively identifying damage of composite material under strong noise background | |
| CN106092879B (en) | Explosion clad pipe bonding state detection method based on vibratory response information | |
| CN110470742B (en) | Accurate detection method for defects of pipeline elbow | |
| CN108195934B (en) | Ultrasonic guided wave detection frequency optimization method based on time-frequency analysis | |
| CN117233257A (en) | Detection method, detection device, detection equipment and storage medium | |
| CN115561307B (en) | Grouting compactness detection method | |
| Sun et al. | Damage identification in thick steel beam based on guided ultrasonic waves | |
| CN110824007A (en) | Tubular pile crack detection method and system | |
| CN113687192B (en) | Method for collecting and positioning discharge signal of power transmission line | |
| CN114778690A (en) | Laser ultrasonic quantitative detection method for pore defects of additive part | |
| CN113533510B (en) | Rail fatigue micro-crack identification method and device | |
| CN115311526A (en) | Defect sample generation method and system based on improved Cycle GAN network | |
| CN105004795A (en) | Pseudo-flaw signal recognition method and method for improving pipeline nondestructive testing precision through same | |
| CN102565193B (en) | Remote pipeline imaging method and system based on guided wave gathered scanning | |
| CN111189912B (en) | Emission reference ultrasonic detection method, device and storage medium | |
| CN110988138B (en) | Weld assembly quality detection device and method | |
| Hensman et al. | Detecting and identifying artificial acoustic emission signals in an industrial fatigue environment | |
| CN113639680B (en) | Method for measuring thickness of pipeline based on SH guided wave frequency dispersion | |
| CN101467895B (en) | Method and apparatus for realizing focusing calculation in continuous Doppler ultrasound system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |