CN114755298A - Method for detecting internal cracks of action rod of turnout switch machine based on ultrasonic technology - Google Patents
Method for detecting internal cracks of action rod of turnout switch machine based on ultrasonic technology Download PDFInfo
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Abstract
The invention discloses a method for detecting internal cracks of an action rod of a turnout switch machine based on an ultrasonic technology, which comprises the following steps: s1: establishing a simulation model of ultrasonic detection of the round rod-shaped action rod, analyzing the characteristics of a sound field and selecting optimal ultrasonic probe parameters; s2: preparing action rod test pieces containing internal cracks with different burial depths and action rod test pieces containing internal cracks with different deflection angles, building an experiment platform, and collecting ultrasonic circumferential scanning signals; s3: carrying out imaging processing on ultrasonic signals of the cracks with different burial depths, establishing a mathematical relation between a probe scanning angle and the crack burial depth in action rod detection, and realizing good positioning detection of the cracks in the round rod-shaped action rod; s4: and imaging ultrasonic signals of the inclined cracks with different deflection angles, establishing a nonlinear relation graph, and realizing quantitative detection of the deflection angle of the inclined crack in the good round rod-shaped action rod. The invention realizes the ultrasonic nondestructive quantitative detection of the internal cracks of the round rod-shaped action rod.
Description
Technical Field
The invention belongs to the technical field of nondestructive testing, and particularly relates to a method for detecting internal cracks of an action rod of a turnout switch machine based on an ultrasonic technology.
Background
The key parts of the turnout switch machine, such as the action rod, are easy to expand cracks and even cause serious accidents due to the action of force in severe environment for a long time. The total number of the turnout switch machines which need to be replaced each year in China is about 45000 thousand. If the aging and damage conditions of the equipment cannot be effectively detected, the equipment itself does not have any damage and still has good working capacity, but is still directly replaced, so that serious resource waste is caused. Therefore, it is necessary to develop a crack detection study for key components such as the operating rod of the turnout switch. However, at present, the detection of the key components of the switch mechanism mainly depends on a visual method, the detection efficiency is low, and internal cracks cannot be found. Modern nondestructive detection technology has become a main technology for railway detection application due to the characteristics of efficient and accurate detection. The ultrasonic detection technology has the advantages of large detection depth and high detection precision, and is suitable for detecting internal cracks.
However, most of the existing ultrasonic detection technologies focus on regular plate-type test piece detection, and detection research on a round bar-shaped component such as an action rod is few, and almost blank in internal crack detection research of the action rod of the point switch machine. The invention aims to overcome the problems that the detection of the action rod of the traditional switch machine mainly depends on manual visual detection and is difficult to detect internal cracks, and overcome the defect that the detection of a round rod-shaped part by the existing ultrasonic flaw detection technology is not suitable.
Disclosure of Invention
The invention aims to provide a method for detecting internal cracks of an action rod of a turnout switch machine based on an ultrasonic technology, which is used for solving the technical problem that the detection of the action rod of the traditional switch machine mainly depends on manual visual detection and is difficult to detect the internal cracks due to the defect that the existing ultrasonic flaw detection technology in the prior art is not suitable for detecting round rod-shaped components.
The method for detecting the internal cracks of the action rod of the turnout switch machine based on the ultrasonic technology comprises the following steps:
s1: and establishing a simulation model of the ultrasonic detection of the round rod-shaped action rod, analyzing the characteristics of a sound field and selecting the optimal parameters of the ultrasonic probe.
S2: and preparing action rod test pieces containing internal cracks with different burial depths and action rod test pieces containing internal cracks with different deflection angles, building an experiment platform, and collecting ultrasonic circumferential scanning signals.
S3: the ultrasonic signals of the cracks with different burial depths are subjected to imaging processing, signal characteristics corresponding to the crack burial depths are analyzed, a mathematical relation between a probe scanning angle and the crack burial depths in action rod detection is established, and good positioning detection of the cracks in the round rod-shaped action rod is achieved.
S4: the ultrasonic signals of the inclined cracks with different deflection angles are imaged, the signal characteristics of the inclined cracks are analyzed, a nonlinear relation graph among the deflection angles of the cracks, the probe scanning angle and the single sound path of the crack echo is established, and the quantitative detection of the deflection angles of the inclined cracks in the round rod-shaped action rod is well achieved.
Preferably, in step S3, B-scan imaging is performed on the collected crack signals with different burial depths to obtain an expanded imaging diagram of the cross section of the action bar test piece, the change rules of the signals of the cracks with different burial depths and the probe scanning angle are analyzed, the single sound path of the crack echo is recorded as h, and the probe scanning angle is recorded as β0And the crack deflection angle is recorded as α0In addition, because the designed crack is arranged on the connecting line of the initial detection point and the axial center point of the action rod test piece, the single acoustic path of the crack echo at the initial position is recorded as h 0When the relative position of the crack does not change, h0I.e. fixed, the scanning angle beta is scanned by rotating the probe0The change is carried out, the single sound path h of the crack echo is changed simultaneously, and the relation between the probe scanning angle and the single sound path of the crack echo in the test piece detection of the action rod is obtained through mathematical analysis and formula derivation of the model:
preferably, in step S4, selecting a plurality of cracks at fixed distances from the center of the action bar specimen in a simulated manner, performing B-scan imaging on the acquired oblique crack signals at different deflection angles to obtain an expanded imaging diagram of the cross section of the action bar specimen, recording a single sound path of a crack echo as h, and simultaneously scanning the probe at a scanning angleDegree is recorded as beta0And the crack deflection angle is recorded as α0In addition, because the designed crack is arranged on the connecting line of the initial detection point and the axial center point of the action rod test piece, the single acoustic path of the crack echo at the initial position is recorded as h0When the relative position of the crack does not change, h0I.e. fixed, the scanning angle beta is scanned by rotating the probe0The change is carried out, the single sound path h of the crack echo is simultaneously changed, and the single sound path at the position with the maximum amplitude of the crack echo is recorded as hvalmax，hvalmaxThe corresponding probe scan angle is recorded as betavalmaxAnd establishing a nonlinear relation graph among the crack deflection angle, the probe scanning angle and the crack echo single sound path according to the image characteristics.
Preferably, the establishing method comprises the steps of firstly establishing a three-dimensional rectangular coordinate system based on a defect included angle, a probe scanning angle and a defect echo single sound path, determining the spatial arrangement of the maximum points of the amplitude values of the crack echoes according to data of an expansion imaging graph of the cross section of the action bar test piece at different crack deflection angles in the three-dimensional rectangular coordinate system, and setting the coordinates of the maximum points of the amplitude values of the crack echoes to be (h)valmax，βvalmax，α0And obtaining a corresponding relation graph through mapping of the spatial arrangement on the corresponding two-dimensional rectangular coordinate system, wherein the relation graph comprises a relation graph between the crack deflection angle and the probe scanning angle corresponding to the position with the maximum crack echo amplitude, and a relation graph between the crack deflection angle and the single sound path at the position with the maximum crack echo amplitude.
Preferably, in step S1, a 2D model of the action bar test piece is established in CIVA simulation software, the model is adapted to the shape and size of the round bar-shaped action bar, a longitudinal wave straight probe is adopted, the excitation signal is a longitudinal wave with multiple frequencies, a plurality of wafers with different diameters are configured for simulation, and the optimal ultrasonic probe parameters are determined by obtaining crack response results in the action bar test piece under different probe frequencies and wafer diameters through simulation.
Preferably, the determining the optimal ultrasonic probe parameter comprises: the sound field characteristics of different probe frequencies and wafer sizes in an action rod material are analyzed according to a detection sound field distribution diagram of different probe frequencies and wafer diameters obtained through simulation, along with increase of the probe frequencies, the central energy of a main detection area of a sound field is gradually gathered but the effective detection range of the sound field is reduced, and along with increase of the wafer sizes, the detection range of the sound field is gradually increased but the central sound energy is seriously diffused and is not gathered.
Preferably, the determining the optimal ultrasonic probe parameter comprises: according to the sound pressure attenuation results on the wave source axes under different crystal oscillator frequencies obtained by the sound field diagrams under different frequencies and wafer sizes, the sound beam attenuation is increased when the frequency is higher, and the sensitivity is reduced; the lower frequency can cause the diffusion of detection energy, the distortion of images and the reduction of resolution; the wafer diameter is increased, so that the detection sensitivity is better.
Preferably, in step S2, a plurality of rod-shaped test pieces with the same or similar shape as the round rod-shaped action rod are prepared as the action rod test pieces, the action rod test pieces are divided into two groups, and two corresponding groups of cracks are designed, where one group of cracks is a plurality of cracks with different positions but the same diameter included angle with the initial detection point, and the other group of cracks is 4 cracks with different deflection angles but the same position in the action rod test piece.
Preferably, in step S2, an ultrasonic detector based on a pulse reflection method is used to perform circumferential clockwise scanning on the test piece, detection data are acquired at equal intervals during the scanning process, the detection result is an a-scan signal, the ultrasonic detector is adjusted according to the optimal ultrasonic probe parameter determined in the previous step, and the signal is displayed in a corresponding upper computer waveform display window in real time.
The invention has the following advantages: 1. the invention provides a method for detecting internal cracks of a switch key component-round bar-shaped action rod of a turnout switch based on an ultrasonic technology, which has low cost and high precision and solves the problem that the detection of the internal cracks of the switch key component-round bar-shaped action rod is difficult to realize.
2. The invention establishes a relational expression between the probe scanning angle and the crack burial depth in the action rod detection, can realize the positioning detection of the cracks with different burial depths in the round rod-shaped action rod, and has accurate detection.
3. The invention establishes a nonlinear relation graph among the deflection angle of the internal inclined crack of the action rod, the scanning angle of the probe and the single sound path of the crack echo, provides reference for detecting the internal inclined crack of the action rod of the turnout switch in engineering, and can realize more accurate quantitative detection on the specific position and deflection angle of the crack according to the relation graph.
Drawings
FIG. 1 is a flow chart of the method for detecting internal cracks of the action rod of the turnout switch machine based on the ultrasonic technology.
FIG. 2 is a diagram of the sound field distribution of the probe corresponding to different center frequencies and different wafer diameters obtained by simulation in the present invention.
FIG. 3 is a graph of the acoustic attenuation along the axis of the wave source at different crystal frequencies obtained by simulation in the present invention.
Fig. 4(a) is a design drawing of an action bar test piece with different preset burial depth cracks in the invention.
FIG. 4(b) is a design diagram of a test piece of an action rod with different cracks preset at different included angles.
FIG. 5 is a schematic diagram of the scanning method used in the experiments of the present invention.
FIG. 6 is a scan developed image of crack signal B for cracks of different depths of burial in the present invention.
FIG. 7 is a schematic diagram showing the relationship between the crack burial depth and the probe scanning angle in the present invention.
FIG. 8 is a plot of crack signal B swept out imaging for different deflection angle cracks in accordance with the present invention.
FIG. 9 is a schematic diagram showing the relationship between the crack deflection angle and the probe scan angle in the present invention.
Fig. 10(a) is a schematic diagram of establishing a three-dimensional rectangular coordinate system and applying the developed imaging graph data according to the present invention.
FIG. 10(b) is a schematic diagram showing the spatial arrangement of the maximum amplitude points of the fixed crack echo in the present invention.
Fig. 10(c) is a graph showing the relationship between the crack deflection angle and the probe scanning angle corresponding to the position where the crack echo amplitude is maximum in the present invention.
FIG. 10(d) is a graph of the relationship between the crack deflection angle and the single acoustic path at the maximum crack echo amplitude in the present invention.
Detailed Description
The following detailed description of the present invention will be given in conjunction with the accompanying drawings, for a more complete and accurate understanding of the inventive concept and technical solutions of the present invention by those skilled in the art.
As shown in fig. 1, the invention provides a method for detecting internal cracks of a switch machine action rod based on an ultrasonic technology, which comprises the following steps:
s1: and establishing a simulation model of the ultrasonic detection of the round rod-shaped action rod, analyzing the characteristics of a sound field and selecting the optimal parameters of the ultrasonic probe.
A2D model of an action rod test piece with the radius of 40mm is established in CIVA simulation software, the model is matched with the shape and the size of a round rod-shaped action rod, a longitudinal wave straight probe is adopted, excitation signals are longitudinal waves of 2.5MHz, 5MHz and 7.5MHz, the diameters of wafers are respectively 6mm, 8mm, 10mm and 12mm, and the model is shown in Table 1. The optimal ultrasonic probe parameters are judged by simulating the crack response results in the action rod test piece under different probe frequencies and wafer diameters, as shown in fig. 2 and 3.
TABLE 1 simulated center frequency and wafer diameter parameter selection
In order to analyze the sound field characteristics of different probe frequencies and wafer sizes in the action bar material, the test sound field distribution diagrams of different probe frequencies and wafer diameters are obtained according to the simulation of table 1, as shown in fig. 2(a) -2 (l). In which, FIGS. 2(a) to 2(c) are sound field distribution diagrams of different frequency probes with a wafer diameter of 6mm, FIGS. 2(d) to 2(f) are sound field distribution diagrams of different frequency probes with a wafer diameter of 8mm, FIGS. 2(g) to 2(i) are sound field distribution diagrams of different frequency probes with a wafer diameter of 10mm, and FIGS. 2(j) to 2(l) are sound field distribution diagrams of different frequency probes with a wafer diameter of 12 mm. FIGS. 2(a) -2 (c) show that when the wafer diameter is 6mm, the sound field width of the 2.5MHz probe is wider, the detection range is larger, and the sound beam at 7.5MHz is narrowest, and the detection range is small. While the 2.5MHz central beam is wider and unfocused, the 5MHz and 7.5MHz have narrower, higher central detection acoustic zones. It is shown that as the probe frequency increases, the central energy of the main detection region of the acoustic field gradually concentrates but the effective detection range of the acoustic field shrinks. FIG. 2(b), FIG. 2(e), FIG. 2(h) and FIG. 2(k) show that when the probe frequency is 5MHz, the sound field center energy of the wafer with 6mm diameter is more concentrated, and the sound field detected by the probe with 12mm diameter is more diffuse. Meanwhile, the effective detection sound field range of the wafer with the diameter of 6mm is the minimum, and the effective detection sound field range of the wafer with the diameter of 12mm is the maximum. It is shown that as the wafer size increases, the detection range of the sound field is gradually increased but the central sound energy is heavily diffused and not concentrated.
The sound pressure attenuation results on the wave source axis at different crystal oscillator frequencies obtained from the sound field patterns at different frequencies and wafer sizes are shown in fig. 3. Fig. 3(a) -3 (c) are the sound attenuation of different probe frequencies at different diameters, respectively. As can be seen, when the wafer diameter is fixed, the sound pressure attenuation at 2.5MHz is significantly lower than that at 5MHz and that at 7.5MHz as the propagation path increases. When the probe frequency is fixed and the wafer diameter is increased, the sound pressure attenuation is reduced, and the distance from the position with weaker attenuation to the surface is increased. Therefore, the higher the frequency, the greater the attenuation of the acoustic beam, and the lower the sensitivity; lower frequencies cause detection energy to spread, image distortion, reduced resolution, and, in addition, increased wafer diameter with better detection sensitivity.
In summary, too high a frequency and too low a wafer diameter lead to a decrease in crack detection sensitivity, which is detrimental to the detection of cracks having a certain depth. Too low a frequency and too high a wafer diameter lead to a reduction in the crack detection resolution, and the occurrence of pattern distortions is detrimental to crack evaluation. Therefore, the selection of 5MHz with moderate frequency and 10mm with moderate wafer diameter can realize the coverage detection of the cracks with different burial depths and the positioning quantitative evaluation of the cracks.
S2: preparing action rod test pieces containing internal cracks with different burial depths and action rod test pieces containing internal cracks with different deflection angles, building an experiment platform, and collecting ultrasonic circumferential scanning signals.
A plurality of rod-shaped test pieces with the same or similar shape with the round rod-shaped action rod are prepared to be used as the action rod test pieces. In this example, several bar-shaped test pieces having a radius of 40mm and a length of 100mm were prepared as test objects. Dividing the action rod test piece into two groups, designing two groups of corresponding cracks, wherein the lengths of the cracks are both 2mm, and as shown in fig. 4(a), one group of the cracks is 4 cracks at different positions, the included angles between the cracks and the diameter of an initial detection point are 90 degrees, and the crack positions are respectively 0mm, 5mm, 10mm and 15mm away from the center; as shown in fig. 4(b), another group of 4 cracks with different deflection angles are located 10mm away from the center of the action bar specimen, and the included angles between the cracks and the diameter of the initial detection point are respectively 60 °, 45 °, 30 ° and 0 °, as shown in table 2.
TABLE 2 internal crack design of action bar test piece
In this embodiment, an ultrasonic detector based on a pulse reflection method is used, the parameters of the detector are shown in table 3, a probe with a center frequency of 5MHz and a wafer diameter of 10mm is selected based on simulation research, a test piece is circumferentially and clockwise scanned at a scanning interval of 1mm corresponding to a central angle of 1.43 degrees for one week to obtain 251 groups of data, and the detection result is an a scanning signal, as shown in fig. 5. The signals can be displayed in a waveform display window of the corresponding upper computer in real time, and the settings of sound velocity, sound path, pulse width, gain, echo suppression, probe zero point and the like can be performed through the parameter setting of the upper computer.
TABLE 3 ultrasonic testing machine parameters
After the initial parameters are set, the position of the bottom wave can be found in the screen by detecting the crack-free test piece with the known thickness and adjusting the sound velocity to enable the position of the bottom echo to be consistent with the theoretical position, so that the sound velocity calibration is completed. When the ultrasonic detection is carried out on the turnout switch machine test piece, the values of the optimal instrument parameters are as follows through test calibration: the sound velocity is 5900m/s, the excitation pulse width is 30ns, the gain is 64dB, the echo suppression is 3%, the zero point of the probe is 0.12 mu s, and the sound path is 80 mm. And after the adjustment is finished, the detection can be started, and when the echo wave appearing between the crack wave and the bottom wave is the crack ripple wave.
S3: the ultrasonic signals of the cracks with different burial depths are subjected to imaging processing, signal characteristics corresponding to the crack burial depths are analyzed, a mathematical relation between a probe scanning angle and the crack burial depths in action rod detection is established, and good positioning detection of the cracks in the round rod-shaped action rod is achieved.
B-scanning imaging is carried out on the collected crack signals with different burial depths to obtain an expanded imaging image of the cross section of the action rod test piece, and the change rule of the signals of the cracks with different burial depths and the scanning angle of the probe is analyzed, as shown in figure 6.
In order to analyze the influence of the change of the internal crack position on the ultrasonic echo in the round bar-shaped structure, the deflection angle of the crack is kept in a state of being vertical to a reference line, and the crack position is respectively 0mm, 5mm, 10mm and 15mm away from the center of the action rod test piece. The probe direction is vertical to the crack direction initially, echo signals at the crack can be directly reflected back to the probe right, the crack echo signals are strongest at the moment, a certain included angle is generated between the normal line of the crack and the central axis of the probe along with the clockwise rotation of the probe along the outer surface of the action rod test piece, a certain signal can be reflected by the end angle at the moment, the vertical distance between two end angles of the crack is increased along with the increase of the included angle, so that the B-scanning signal can generate branching, and the phenomenon is most obvious particularly when the crack position is at 0 mm. When the included angle between the normal line of the crack and the central axis of the probe is 90 degrees, if the crack position is at the center of the action rod test piece, for the probe at the moment, the crack has only an end point close to one end of the surface, and if the crack position is not at the center, most of ultrasonic waves in the vertical direction are avoided. When the probe continues to scan along the outer surface, the included angle between the normal line of the crack and the central axis of the probe is reduced, the signal change is opposite to that before, until the included angle between the position of the probe and the crack is 180 degrees, at this time, the probe has scanned a half cycle, and it can be known from fig. 6 that a stronger crack echo signal appears for the second time in the scanning result B, the signal is essentially the same crack information as that shown in the initial position, and similarly, the same crack is shown in the position where the stronger echo signal appears for the third time, and the stronger crack echo signal can be spliced with the echo signal in the initial position to form a continuous result. In general, the bar material (namely the action bar test piece) is detected to have a special B-scanning result chart due to the particularity of the peripheral outline, but still can be clearly positioned, and according to the sound velocity calculation of 5900m/s in steel, the crack echo single sound paths of the crack in the initial position of the probe in (B-c) in the graph 6 are respectively 20mm, 15mm, 10mm and 5mm, and when the probe is scanned and rotated to 180 degrees, the crack echo single sound paths are respectively 20mm, 25mm, 30mm and 35 mm. Therefore, the probe of the ultrasonic longitudinal wave is used for detecting the position of the crack in the round bar-shaped structure, the result is clear and easy to distinguish, and the scheme is feasible.
From the above analysis, a mathematical relationship of the probe position and the variation of the internal crack detection position can be established, as shown in fig. 7. When the probe scans along the circumferential direction of the outer surface of the action rod test piece, because the straight probe has a certain diffusion angle, when the crack position is not on the straight line of the axis of the probe, a certain crack echo can be detected, the single sound path of the crack echo is recorded as h, and meanwhile, the probe scanning angle is recorded as beta0And the crack deflection angle is recorded as α0In addition, because the designed crack is arranged on the connecting line of the initial detection point and the axial center point of the action rod test piece, the single acoustic path of the crack echo at the initial position is recorded as h0When the relative position of the crack does not change, h0I.e. fixed, the scanning angle beta is scanned by rotating the probe0The change is carried out, the single sound path h of the crack echo is changed simultaneously, and the relation between the probe scanning angle and the single sound path of the crack echo in the test piece detection of the action rod is obtained through mathematical analysis and formula derivation of the model:
s4: the ultrasonic signals of the inclined cracks with different deflection angles are imaged, the characteristics of the inclined crack signals are analyzed, a nonlinear relation graph among the crack deflection angle, the probe scanning angle and the crack echo single sound path is established, and good quantitative detection of the deflection angle of the inclined cracks in the round rod-shaped action rod is achieved.
In order to analyze the influence of the change of the deflection angle of the internal crack on the ultrasonic echo in the round bar-shaped structure, four-angle cracks are designed at the position 10mm away from the center of the action rod test piece in a simulation mode, the included angles between the four-angle cracks and the axial lead of a probe at the initial detection point are respectively 60 degrees, 45 degrees, 30 degrees and 0 degree, B-scan imaging is carried out on the collected oblique crack signals with different deflection angles, and an expansion imaging graph of the cross section of the action rod test piece is obtained, wherein the expansion imaging graph is shown in figure 8. The information reflected by the two areas with larger echo amplitude points to the same crack, which is mainly because the scanning path of the probe is a whole circle, and when the probe rotates for half a circle, the displayed information is just corresponding to the information detected at the position on the other side of the longitudinal section extending along the diameter of the action rod test piece, and the two measured signals are just symmetrical about the center position of the action rod test piece. As can be seen from fig. 8, when the crack depth position is fixed, the overall position of the echo signal of the crack appearing in the B-scan does not change, and as the included angle between the crack and the axial lead of the probe at the initial detection point decreases, the strongest point of the echo signal gradually shifts towards the direction of increasing the scanning angle in the circumferential direction of the detection probe, that is, when the position of the probe is near the intersection point of the normal line of the crack and the circumference, the echo signal at the corresponding position will increase, and as long as the relationship between the two can be determined, the depth and the deflection angle of the crack can be determined by the echo signal.
As shown in fig. 9, when the probe scans circumferentially along the outer surface of the action bar test piece, since the straight probe has a certain diffusion angle, the crack echo single sound path is recorded as h, and the probe scanning angle is recorded as β0And the crack deflection angle (i.e. included defect angle) is recorded as alpha0In addition, because the designed crack is arranged on a connecting line of the initial detection point and the axial center point of the action rod test piece, the single acoustic path of the crack echo at the initial position is recorded as h0When the relative position of the crack is notWhen a change occurs, h0I.e. fixed, the scanning angle beta is scanned by rotating the probe0The change occurs, simultaneously the single acoustic path h associated with the crack echo changes, and the single acoustic path at the maximum amplitude of the illustrated crack echo (i.e., the defect echo single acoustic path) is denoted as hvalmax，hvalmaxThe corresponding probe scan angle is recorded as betavalmax。
And establishing a nonlinear relation graph among the crack deflection angle, the probe scanning angle and the crack echo single sound path according to the image characteristics, as shown in FIG. 10. The establishing method comprises the steps of firstly establishing a three-dimensional rectangular coordinate system based on a defect included angle, a probe scanning angle and a defect echo single sound path, as shown in figure 10(a), determining the spatial arrangement of maximum points of crack echo amplitude values according to data of an unfolded imaging graph of the cross section of an action rod test piece with different defect included angles in the three-dimensional rectangular coordinate system, as shown in figure 10(b), wherein the coordinates of the maximum points of the crack echo amplitude values are (h) valmax，βvalmax，α0And obtaining a corresponding relation diagram through mapping of the spatial arrangement on the corresponding two-dimensional rectangular coordinate system, wherein the relation diagram comprises a relation diagram between the crack deflection angle and the probe scanning angle corresponding to the position with the maximum crack echo amplitude, and a relation diagram between the crack deflection angle and the single sound path at the position with the maximum crack echo amplitude, and the relation diagrams are shown in 10(c) and 10 (d). Based on the relation diagram, the position information (namely the single sound path of the defect echo) and the deflection angle of the crack can be obtained only by knowing the scanning angle of the probe, and the method for positioning and quantitatively detecting the angle of the internal inclined crack is provided.
The invention is described above with reference to the accompanying drawings, it is obvious that the specific implementation of the invention is not limited by the above-mentioned manner, and it is within the scope of the invention to adopt various insubstantial modifications of the inventive concept and solution of the invention, or to apply the inventive concept and solution directly to other applications without modification.
Claims (9)
1. A method for detecting internal cracks of an action rod of a turnout switch machine based on an ultrasonic technology is characterized by comprising the following steps: comprises the following steps:
s1: establishing a simulation model of ultrasonic detection of the round rod-shaped action rod, analyzing the characteristics of a sound field and selecting optimal ultrasonic probe parameters;
S2: preparing action rod test pieces containing internal cracks with different burial depths and action rod test pieces containing internal cracks with different deflection angles, building an experiment platform, and collecting ultrasonic circumferential scanning signals;
s3: carrying out imaging processing on ultrasonic signals of the cracks with different burial depths, analyzing signal characteristics corresponding to the burial depths of the cracks, establishing a mathematical relation between a probe scanning angle and the burial depths of the cracks in the action rod detection, and realizing good positioning detection of the cracks in the round rod-shaped action rod;
s4: the ultrasonic signals of the inclined cracks with different deflection angles are imaged, the signal characteristics of the inclined cracks are analyzed, a nonlinear relation graph among the deflection angles of the cracks, the probe scanning angle and the single sound path of the crack echo is established, and the quantitative detection of the deflection angles of the inclined cracks in the round rod-shaped action rod is well achieved.
2. The method of claim 1, wherein the method comprises the steps of: in the step S3, B-scan imaging is performed on the collected crack signals of different burial depths to obtain an expanded imaging diagram of the cross section of the action rod test piece, the change rules of the crack signals of different burial depths and the probe scan angle are analyzed, the single sound path of the crack echo is recorded as h, and the probe scan angle is recorded as beta 0And the crack deflection angle is recorded as α0In addition, because the designed crack is arranged on the connecting line of the initial detection point and the axial center point of the action rod test piece, the single acoustic path of the crack echo at the initial position is recorded as h0When the relative position of the crack does not change, h0I.e. fixed, the probe is rotated to scan the angle beta0The change is carried out, the single sound path h of the crack echo is changed simultaneously, and the relation between the probe scanning angle and the single sound path of the crack echo in the test piece detection of the action rod is obtained through mathematical analysis and formula derivation of the model:
3. the method for detecting internal cracks of the action rod of the turnout switch machine based on the ultrasonic technology as claimed in claim 2, wherein: in the step S4, simulating and selecting cracks at a plurality of angles at a fixed distance from the center of the action bar test piece, performing B-scan imaging on the acquired oblique crack signals at different deflection angles to obtain an expanded imaging diagram of the cross section of the action bar test piece, recording a single sound path of a crack echo as h, and recording a probe scan angle as beta0And the crack deflection angle is recorded as alpha0In addition, because the designed crack is arranged on the connecting line of the initial detection point and the axial center point of the action rod test piece, the single acoustic path of the crack echo at the initial position is recorded as h 0When the relative position of the crack does not change, h0I.e. fixed, the scanning angle beta is scanned by rotating the probe0The change is carried out, the single sound path h of the crack echo is simultaneously changed, and the single sound path at the position with the maximum amplitude of the crack echo is recorded as hvalmax，hvalmaxThe corresponding probe scan angle is recorded as betavalmaxAnd establishing a nonlinear relation graph among the crack deflection angle, the probe scanning angle and the crack echo single sound path according to the image characteristics.
4. The method for detecting internal cracks of the action rod of the turnout switch machine based on the ultrasonic technology as claimed in claim 3, wherein: the establishing method comprises the steps of firstly establishing a three-dimensional rectangular coordinate system based on a defect included angle, a probe scanning angle and a defect echo single sound path, determining the spatial arrangement of the maximum points of the amplitude values of the crack echoes in the three-dimensional rectangular coordinate system according to data of an unfolded imaging graph of the cross section of an action rod test piece with different crack deflection angles, wherein the coordinate of the maximum point of the amplitude values of the crack echoes is (h)valmax，βvalmax，α0And obtaining a corresponding relation graph by mapping the spatial arrangement on a corresponding two-dimensional rectangular coordinate system, wherein the relation graph comprises the correspondence of the crack deflection angle and the maximum crack echo amplitudeThe probe scanning angle and the single sound path at the maximum crack echo amplitude are respectively obtained by the probe scanning angle and the single sound path at the maximum crack echo amplitude.
5. The method of claim 1, wherein the method comprises the steps of: in the step S1, a 2D model of the action bar test piece is established in the CIVA simulation software, the model is adapted to the shape and size of the round bar-shaped action bar, a longitudinal wave straight probe is adopted, the excitation signal is a longitudinal wave with multiple frequencies, a plurality of wafers with different diameters are configured for simulation, and the optimal ultrasonic probe parameters are determined by obtaining crack response results in the action bar test piece under different probe frequencies and wafer diameters through simulation.
6. The method of claim 5, wherein the method comprises the steps of: the judging of the optimal ultrasonic probe parameters comprises the following steps: the sound field characteristics of different probe frequencies and wafer sizes in an action rod material are analyzed according to a detection sound field distribution diagram of different probe frequencies and wafer diameters obtained through simulation, as the probe frequencies increase, the central energy of a main detection area of a sound field gradually gathers but the effective detection range of the sound field is reduced, and as the wafer sizes increase, the detection range of the sound field gradually increases but the central sound energy is seriously diffused and is not concentrated.
7. The method for detecting internal cracks of a switch machine action rod based on the ultrasonic technology as claimed in claim 5 or 6, characterized in that: the judging of the optimal ultrasonic probe parameters comprises the following steps: according to the sound pressure attenuation results on the wave source axis under different crystal oscillator frequencies obtained by the sound field diagrams under different frequencies and wafer sizes, the sound beam attenuation is increased when the frequency is higher, and the sensitivity is reduced; the lower frequency can cause the diffusion of detection energy, the distortion of images and the reduction of resolution; the detection sensitivity is better when the diameter of the wafer is increased.
8. The method for detecting internal cracks of the action rod of the turnout switch machine based on the ultrasonic technology as claimed in claim 1, wherein: in step S2, a plurality of rod-shaped test pieces having the same or similar shape as the round rod-shaped action bar are prepared as the action bar test pieces, the action bar test pieces are divided into two groups, and two corresponding groups of cracks are designed, where one group of cracks is a plurality of cracks having different positions but the same diameter included angle with the initial detection point, and the other group of cracks is 4 cracks having different deflection angles but the same position in the action bar test piece.
9. The method for detecting internal cracks of the action rod of the turnout switch machine based on the ultrasonic technology as claimed in claim 1, wherein: in the step S2, an ultrasonic detector based on a pulse reflection method is used to perform circumferential clockwise scanning on the test piece, detection data are acquired at equal intervals in the scanning process, the detection result is an a-scan signal, the ultrasonic detector is adjusted according to the optimal ultrasonic probe parameter determined in the previous step, and the signal is displayed in a corresponding upper computer waveform display window in real time.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115375693A (en) * | 2022-10-27 | 2022-11-22 | 浙江托普云农科技股份有限公司 | Method, system and device for detecting defects of probe of agricultural information acquisition sensor |
| CN116381052A (en) * | 2023-06-07 | 2023-07-04 | 中国空气动力研究与发展中心设备设计与测试技术研究所 | Probe parameter determination method for TOFD detection of inner surface defect of outer cylinder |
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2022
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115375693A (en) * | 2022-10-27 | 2022-11-22 | 浙江托普云农科技股份有限公司 | Method, system and device for detecting defects of probe of agricultural information acquisition sensor |
| CN115375693B (en) * | 2022-10-27 | 2023-02-10 | 浙江托普云农科技股份有限公司 | Method, system and device for detecting defects of probe of agricultural information acquisition sensor |
| CN116381052A (en) * | 2023-06-07 | 2023-07-04 | 中国空气动力研究与发展中心设备设计与测试技术研究所 | Probe parameter determination method for TOFD detection of inner surface defect of outer cylinder |
| CN116381052B (en) * | 2023-06-07 | 2024-03-01 | 中国空气动力研究与发展中心设备设计与测试技术研究所 | Probe parameter determination method for TOFD detection of inner surface defect of outer cylinder |
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