A device and method for detecting fatigue cracks in orthotropic steel box girder plates

Abstract

The application discloses a kind of detection device and method for steel box beam orthotropic plate fatigue crack, comprising: steel box beam orthotropic plate fatigue structure, steel box beam orthotropic plate fatigue structure is provided with measurement probe and probe scanning frame, measurement probe is mechanically connected probe scanning frame by universal table rod, measurement probe is electrically connected magnetic memory detector by probe line.The beneficial effects of the present application are: the orthotropic plate crack condition can be accurately detected by magnetic memory signal.

Description

Technical Field

[0001] This invention relates to the field of fatigue assessment technology for steel bridges, and in particular to a device and method for detecting fatigue cracks in orthotropic plates of steel box girders. Background Technology

[0002] Steel box girder orthotropic plate structures have become the main form of bridge deck for long-span steel bridges due to their good overall performance and material savings. However, their complex local structure, intersecting weld spaces, and high randomness of vehicle loads on the bridge deck increase the probability of fatigue cracks, making fatigue assessment more difficult. Furthermore, because cracks are difficult to detect in their early stages, the optimal time to implement effective measures is often missed.

[0003] In existing technologies, dynamic strain gauge measurement is generally used to assess the fatigue of steel bridges. This involves attaching strain gauges to the structural members or installing steel wire strain gauges to measure the strain history, followed by an assessment after investigating bridge damage caused by past traffic loads. However, the placement of strain gauges or steel wire strain gauges is limited by the complex structure of the bridge, and the difficulty in researching historical bridge data leads to errors in previous fatigue damage assessments, resulting in low accuracy in fatigue assessments extrapolated from measurement results. Furthermore, it cannot accurately detect cracks in orthotropic plates using magnetic memory signals.

[0004] For example, a "bridge inspection vehicle" disclosed in Chinese patent literature, publication number CN113022508A, application date: September 7, 2015, includes a support leg mechanism. The support leg mechanism includes a frame, a hydraulic cylinder, a wheel frame, and support leg components. The support leg components are provided with a first hinge position, a second hinge position, and a third hinge position. The first hinge position is hinged to the frame, the second hinge position is hinged to the wheel frame, and the third hinge position is hinged to one end of the hydraulic cylinder. The other end of the hydraulic cylinder is hinged to the frame. The third hinge position is located between the first and second hinge positions, and the first, second, and third hinge positions are located on the same plane. This invention can solve the problem of excessive load on some hinge points caused by unreasonable hinge point design in current bridge inspection vehicle support leg mechanisms, which leads to local structural damage caused by the load transmitted to the frame platform. However, it has the problem that it cannot accurately detect orthotropic plate cracks through magnetic memory signals. Summary of the Invention

[0005] To address the shortcomings of existing technologies that cannot accurately detect orthotropic plate cracks using magnetic memory signals, this invention proposes a device and method for detecting fatigue cracks in orthotropic plates of steel box girders, which can accurately detect orthotropic plate cracks using magnetic memory signals.

[0006] The following is the technical solution of the present invention: a device for detecting fatigue cracks in orthotropic plates of steel box girders, comprising: a fatigue structure of orthotropic plates of steel box girders, wherein the fatigue structure of orthotropic plates of steel box girders is provided with a measuring probe and a probe scanning frame, the measuring probe is mechanically connected to the probe scanning frame via a universal joint rod, and the measuring probe is electrically connected to a magnetic memory detector via a probe line.

[0007] In this scheme, a measuring probe is installed on the fatigue structure of the orthotropic steel box girder. The measuring probe is used to acquire the magnetic field information of the fatigue structure of the orthotropic steel box girder. The measuring probe is mechanically connected to a probe scanning frame via a universal joint. During measurement, the scanning frame controls the travel direction and speed of the measuring probe, enabling the measuring probe to scan at a uniform speed in a specified direction at the measurement site. The measuring probe is electrically connected to a magnetic memory detector via a probe line. The magnetic memory detector simultaneously records the vertical and tangential magnetic memory signals of the surface of the measured object, which are used for storage, playback, analysis, identification, and output. This allows for accurate detection of cracks in the orthotropic steel box girder using the magnetic memory signals.

[0008] Preferably, in the measuring probe, the outer corner of the sensor position fixer is provided with a concave arc, and the two ends of the sensor position fixer are respectively provided with a first fixing plane and a second fixing plane. The first fixing plane is provided with a first one-way roller and a first sensor, and the second fixing plane is provided with a second one-way roller and a second sensor. The first sensor and the second sensor are electrically connected to the magnetic memory detector through the probe line.

[0009] In this design, the first and second sensors each lead out magnetic memory signal lines, including a normal Y-axis signal channel, a tangential Z-axis signal channel, and two corresponding temperature compensation signal channels. These eight signal lines are combined and fixed within a 16-core probe line. The probe line is connected to the magnetic memory detector, simultaneously measuring the normal Y-axis and tangential Z-axis magnetic memory signals along the two paths of the first and second sensors, thus improving measurement efficiency. The sensor position holder has a first fixed plane and a second fixed plane at its two ends. The first and second sensors are mechanically mounted on these planes, with a first unidirectional roller and a second unidirectional roller mounted on their outer sides, positioned between them. The height difference between the first and second unidirectional rollers is 2mm, and similarly, the height difference between the first and second unidirectional rollers is also 2mm. During measurement, the first and second unidirectional rollers move closely against the surface of the tested part of the fatigued structure, ensuring that the lift-off values ​​of the first and second sensors are measured evenly within a 2mm range. On the one hand, this allows the probe to smoothly pass over individual weld protrusions or other uneven objects during measurement; on the other hand, it ensures the effective acquisition of magnetic memory signals.

[0010] Preferably, the first sensor and the second sensor are located between the first unidirectional roller and the second unidirectional roller.

[0011] In this scheme, the first sensor and the second sensor can rotate 90° within the plane of the first fixed plane and the second fixed plane, respectively, so that the tangential signal of the sensor is perpendicular to the rolling direction, which is the tangential Z signal; or parallel to the rolling direction, which is the tangential X signal. This satisfies the requirements for fillet weld measurement and planar path measurement in the fatigue structure of orthotropic plates, expands the application range of the measuring probe, and improves its flexibility.

[0012] Preferably, the included angle between the first fixed plane and the second fixed plane is 90° to 180°; when the included angle is 180°, the direction of the roller bearing is parallel to the line connecting the first sensor and the second sensor; when the included angle is 90°, the tangential Z signal of the sensor is perpendicular to or parallel to the roller traveling direction X; when they are parallel, the tangential Z signal of the sensor is converted into a tangential X signal.

[0013] In this design, the inner angle rotation range of the sensor position fixer is 90° to 180°, and the outer corner is provided with a 10×10mm concave arc to allow the fillet weld of the measurement part to meet the requirements of different fillet weld structures in the fatigue structure of orthotropic plates.

[0014] As a preferred embodiment, in the probe scanning frame, the bracket is connected to the electric X-axis, the electric X-axis is connected to the electric Z-axis, the electric Z-axis is equipped with an electric slide rail, the electric slide rail is connected to the universal joint rod and the control cabinet, the universal joint rod is connected to the measuring probe, and the control cabinet is connected to the direction controller and the 220V power supply.

[0015] In this design, the front end of the universal joint rod is mechanically fixed to the measuring probe, and the rear end of the universal joint rod is mechanically fixed to the electric slide rail. The electric slide rail, electric Z-axis, and electric X-axis are assembled on a bracket. The bracket connects to the electric X-axis, the electric X-axis connects to the electric Z-axis, and the electric Z-axis has an electric slide rail connected to the universal joint rod. During measurement, the bracket is first securely positioned so that the measuring probe can easily contact the measurement area of ​​the orthotropic plate fatigue structure. The electric slide rail is electrically connected to the control cabinet, and the control cabinet is electrically connected to the direction controller. The control cabinet is also connected to a 220V power supply.

[0016] Preferably, the electric slide is electrically connected to the control cabinet, which controls the moving speed of the electric slide; the control cabinet is electrically connected to the direction controller, which controls the relative position of the electric slide on the electric X-axis and the electric Z-axis.

[0017] In this design, the electric slide is electrically connected to the control cabinet. When the control cabinet knob is turned to "position 1", the electric slide will move at a constant speed of 30mm / s. When the control cabinet knob is turned to "position 2" and "position 3", the control cabinet controls the electric slide to move at speeds of 50mm / s and 65mm / s respectively. The control cabinet is also electrically connected to the direction controller. When the direction controller knob is turned to the "left / right" position, the electric slide moves along the electric X-axis. When the knob is turned to the "up / down" position, the electric slide moves along the electric Z-axis.

[0018] As a preferred embodiment, in the orthotropic plate fatigue structure of the steel box girder, the U-rib and the bridge deck are connected to form a fillet weld structure between the U-rib and the bridge deck, and the U-rib and the diaphragm are connected to form a fillet weld structure between the U-rib and the diaphragm and a notched arc edge structure between the U-rib and the diaphragm.

[0019] Preferably, the fillet weld angle between the U-rib and the bridge deck is 103°, and the fillet weld angle between the U-rib and the diaphragm is 90°.

[0020] A method for detecting fatigue cracks in orthotropic plates of steel box girders includes the following steps:

[0021] S1: Pre-treatment detection area;

[0022] S2: Place the measuring probe in the detection area;

[0023] S3: Set the moving speed of the electric slide based on the measurement path;

[0024] S4: Set the relative position of the electric slide rail on the electric X-axis and electric Z-axis based on the measurement direction;

[0025] S5: Acquire magnetic field signals, obtain data files and graphic files based on the magnetic field signals, and obtain detection results based on the data files and graphic files.

[0026] In this scheme, the pre-processing of the inspection area involves marking lines at the starting and ending points of the fillet weld measurement according to a preset length; placing the measuring probe in the inspection area and stably positioning the probe scanning frame near the measurement location of the orthotropic plate inside the steel box girder; setting the moving speed of the electric slide based on the measurement path, with the control cabinet providing speeds of 1, 2, and 3, all of which ensure measurement quality; setting the relative position of the electric slide on the electric X-axis and electric Z-axis based on the measurement direction, moving the electric slide along the electric X-axis when the direction controller knob is turned to the "left / right" position, and moving it along the electric Z-axis when the knob is turned to the "up / down" position; acquiring magnetic field signals, obtaining data files and graphic files based on the magnetic field signals, and obtaining the inspection results based on the data files and graphic files. After acquiring the data files and graphic files of the magnetic memory signals of the orthotropic plate of the steel box girder through the magnetic memory detector, the acquired data files and graphic files are analyzed and processed. In actual measurement, various results will occur, requiring comprehensive judgment to obtain the detection results of fatigue cracks in the orthotropic plate of the steel box girder. It can accurately detect cracks in orthotropic plates through magnetic memory signals.

[0027] Preferably, in step S2, adjusting the inner angle of the sensor position fixer and simultaneously adjusting the tangential Z-signal directions of the first and second sensors includes: placing the measuring probe at the fillet weld between the inner U-rib of the steel box girder and the bridge deck, adjusting the inner angle of the sensor position fixer to 103°, and adjusting the tangential Z-signal directions of the first and second sensors to be perpendicular to the roller's travel direction; placing the measuring probe at the fillet weld above the arc-shaped notch of the weld between the inner U-rib of the steel box girder and the transverse diaphragm, adjusting the inner angle of the sensor position fixer to 90°, and adjusting the tangential Z-signal directions of the first and second sensors to be perpendicular to the roller's travel direction; and placing the measuring probe at the arc-shaped edge of the notch between the inner U-rib of the steel box girder and the transverse diaphragm, adjusting the inner angle of the sensor position fixer to 180°, and adjusting the tangential Z-signal directions of the first and second sensors to be parallel to the roller's travel direction.

[0028] The beneficial effects of this invention are:

[0029] 1. By using a variable measuring probe, the magnetic memory signals of three specific structures of orthotropic plates are accurately measured, which solves the problem of accurate detection in areas where cracks are prone to occur in orthotropic plates, and at the same time improves the identifiability of fatigue cracks.

[0030] 2. The equipment can be installed quickly, solving the problem of the inability to place the testing instruments in the narrow operating space of the steel box girder on site; it realizes the synchronous acquisition of vertical and tangential signal data, improves the flexibility and effectiveness of fatigue crack detection of orthotropic plates of steel box girders, and reduces the missed detection rate;

[0031] 3. No sensors need to be installed on the monitored object, and no large number of guy wires are required. It can collect the magnetic memory signal of the monitored object in real time within the steel box girder when vehicles pass by, minimizing the mutual interference between on-site measurement and normal bridge traffic.

[0032] 4. No treatment is needed to prevent rust on the steel surface during the test. The probe simply scans across the surface of the measurement area, eliminating the need for consumables such as strain gauges, wires, adhesives, sandpaper, and insulating glue required by conventional monitoring techniques, as well as the grinding process on the measurement point surface. Therefore, this invention has the advantages of zero wear and low measurement cost. Attached Figure Description

[0033] Figure 1 The present invention provides a schematic diagram of the structure of a device for detecting fatigue cracks in orthotropic plates of steel box girders.

[0034] Figure 2 A schematic diagram of the structure of the measuring probe provided by the present invention.

[0035] Figure 3 A schematic diagram of the probe scanning frame provided by this invention.

[0036] Figure 4 A schematic diagram of the magnetic memory detector provided by this invention.

[0037] Figure 5 A schematic diagram of the orthogonal anisotropic plate measurement structure provided by the present invention.

[0038] Figure 6 A flowchart of the fatigue crack detection method for orthotropic plates of steel box girders provided in this embodiment of the invention.

[0039] Figure 7 A line drawing illustrating a specific example of fatigue crack detection in the fillet weld between the U-rib and the bridge deck in this invention.

[0040] Figure 8 A line drawing illustrating a specific example of fatigue crack detection in the fillet weld between the U-rib and the diaphragm in this invention.

[0041] Figure 9 A scribing diagram illustrating a specific example of fatigue crack detection at the edge of an arc-shaped notch in this invention.

[0042] Figure 10 A magnetic memory signal effect diagram of a specific example of fatigue crack detection of fillet welds provided by the present invention.

[0043] Figure 11 A magnetic memory signal effect diagram of a specific example of fatigue crack detection at the edge of an arc-shaped notch provided by the present invention.

[0044] In the figure, 100 is the measuring probe; 200 is the probe scanning frame; 300 is the magnetic memory detector; and 400 is the fatigue structure of the orthotropic plate of the steel box girder.

[0045] 1. Probe cable; 2. First sensor; 3. Second sensor; 4. Sensor position holder; 5. First fixed plane; 6. Second fixed plane; 7. Concave arc; 8. First one-way roller; 9. Second one-way roller; 10. Universal gauge rod; 11. Electric slide rail; 12. Electric Z-axis; 13. Electric X-axis; 14. Bracket; 15. Control cabinet; 16. Direction controller; 17. 220V power supply; 18. LCD display; 19. Calibration button; 20. Data storage module; 21. Data analysis module; 22. Data communication module; 23. 16-pin probe interface; 24. USB interface; 25. Built-in rechargeable battery; 26. U-rib; 27. Bridge deck; 28. Transverse diaphragm; 29. ​​Fillet weld construction between U-rib and bridge deck; 30. Fillet weld construction between U-rib and transverse diaphragm; 31. Arc-shaped edge construction of U-rib and transverse diaphragm notch.

[0046] Among them, 1 to 9 constitute 100; 10 to 17 constitute 200; 18 to 25 constitute 300; and 26 to 31 constitute 400. Detailed Implementation

[0047] The technical solutions of the present invention and how they solve the above-mentioned technical problems will be described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0048] First, it should be noted that this invention only relates to the hardware equipment used for magnetic signal acquisition and data transmission during fatigue crack detection of orthotropic steel box girders, as well as the description of their positional or connection relationships. This invention does not involve specific data management and data analysis processes. After data acquisition, the specific processing and analysis of the data can be determined by those skilled in the art, who can choose existing data management and analysis software (such as EMS-2000 magnetic memory analysis software) or program it themselves according to the final analysis objective. However, this part is not part of the technical solution of this invention and should not be used to evaluate this invention. This is hereby stated.

[0049] Example 1:

[0050] like Figure 1As shown, a device for detecting fatigue cracks in orthotropic plates of steel box girders includes: a measuring probe 100, a probe scanning frame 200, a magnetic memory detector 300, and a fatigue structure 400 for orthotropic plates of steel box girders.

[0051] The measuring probe 100 and the probe scanning frame 200 are mechanically connected via a universal joint rod 10. The measuring probe 100 and the probe scanning frame 200 are placed on the measured part of the orthotropic plate fatigue structure 400 of the steel box girder. The measuring probe 100 and the magnetic memory detector 300 are electrically connected via a probe cable 1. During measurement, the scanning frame controls the travel direction and speed of the measuring probe 100, and the magnetic memory detector 300 simultaneously records the vertical and tangential magnetic memory signals of the surface of the measured object.

[0052] like Figure 2 As shown, in the measuring probe 100, the first sensor 2 and the second sensor 3 respectively lead out 4 channels of magnetic memory signal lines, including a normal Y signal channel, a tangential Z signal channel, and two corresponding temperature compensation signal channels. The 8 channels of signal lines are combined and fixed in the 16-core probe line 1. The probe line 1 is connected to the magnetic memory detector 300 to simultaneously measure the normal Y and tangential Z direction magnetic memory signals of the two paths where the first sensor 2 and the second sensor 3 are located, thereby improving the measurement efficiency.

[0053] The sensor position fixer 4 has a first fixing plane 5 and a second fixing plane 6 at its two ends respectively; the included angle θ of the sensor position fixer 4 can vary between 90° and 180°, and a 10×10mm concave arc 7 is provided at the outer corner to allow the fillet weld of the measurement part to meet the requirements of different fillet weld structures in the fatigue structure of orthotropic plates.

[0054] The first sensor 2 and the second sensor 3 are mechanically mounted on the first fixed plane 5 and the second fixed plane 6, respectively. A first one-way roller 8 and a second one-way roller 9 are respectively mounted on their outer sides, with the first sensor 2 and the second sensor 3 positioned between the first one-way roller 8 and the second one-way roller 9. The height difference between the first one-way roller 8 and the first sensor 2 is 2mm, and similarly, the height difference between the second one-way roller 9 and the second sensor 3 is 2mm. During measurement, the first one-way roller 8 and the second one-way roller 9 move closely against the surface of the measured part of the fatigue structure, ensuring that the measurement lift-off values ​​of the first sensor 2 and the second sensor 3 are measured evenly within 2mm. This allows the probe to smoothly glide over individual weld protrusions or other uneven objects during measurement, while also ensuring effective acquisition of magnetic memory signals.

[0055] The first sensor 2 and the second sensor 3 can each rotate 90° within the planes of the first fixed plane 5 and the second fixed plane 6, so that the tangential signal of the sensor is perpendicular to the direction of the roller's travel (tangential Z signal) or parallel to the direction of the roller's travel (tangential X signal). This satisfies the requirements for fillet weld measurement and planar path measurement in orthotropic plate fatigue structures, expands the application range of the measuring probe 100, and improves its flexibility.

[0056] The sensor position fixer 4 is connected to the probe scanning frame 200 and is used to control the traveling direction and speed of the first sensor 2 and the second sensor 3.

[0057] like Figure 3 As shown, in the probe scanning frame 200, the front end of the universal joint rod 10 is mechanically fixed to the measuring probe 100, and the rear end of the universal joint rod 10 is mechanically fixed to the electric slide rail 11. The electric slide rail 11, the electric Z-axis 12, and the electric X-axis 13 are assembled on the bracket 14. The bracket 14 is connected to the electric X-axis 13, and the electric X-axis 13 is connected to the electric Z-axis 12. The electric Z-axis 12 is provided with the electric slide rail 11, which is connected to the universal joint rod 10. During measurement, the bracket 14 is first placed securely so that the measuring probe 100 can easily contact the measurement part of the orthotropic plate fatigue structure.

[0058] The electric slide 11 is electrically connected to the control cabinet 15. When the control cabinet 15 knob is turned to "position 1", the electric slide 11 will move at a constant speed of 30mm / s. When the control cabinet 15 knob is turned to "position 2" and "position 3", the control cabinet 15 controls the electric slide 11 to move at speeds of 50mm / s and 65mm / s respectively.

[0059] The control cabinet 15 is also electrically connected to the direction controller 16. When the knob of the direction controller 16 is turned to the "left and right" position, the electric slide rail 11 moves along the electric X-axis 13. When the knob is turned to the "up and down" position, the electric slide rail 11 moves along the electric Z-axis 12.

[0060] The control cabinet 15 is also connected to or has a built-in 220V power supply 17.

[0061] like Figure 4As shown, in the magnetic memory detector 300, probe line 1 is connected to the 16-pin probe interface 23. After powering on, the calibration button 19 is activated on the LCD screen 18. The Y-direction arrows of the first sensor 2 and the second sensor 3 in the measuring probe 100 are aligned upwards, and the calibration button 19 is clicked. Then, the Z-direction arrows of the first sensor 2 and the second sensor 3 are aligned upwards, and the calibration button 19 is clicked again to complete the calibration between the magnetic memory detector 300 and the measuring probe 100. During measurement, the data storage module 20 is activated to continuously record measurement data. After measurement, the data analysis module 21 is activated to process the measurement data, generating data files and graphic files. The measured data files and graphic files can be uploaded to the network via the data communication module 22 or copied via the USB interface 24 to a computer for analysis and processing to obtain the detection results of fatigue cracks in the orthotropic plates of the steel box girder.

[0062] The magnetic memory detector 300 also has a built-in rechargeable battery 25.

[0063] like Figure 5 As shown, in the orthotropic plate fatigue structure 400 of the steel box girder, the orthotropic plate is composed of U-ribs 26, bridge deck 27, and transverse diaphragms 28 through spatial welds, resulting in three common fatigue structures: U-rib and bridge deck fillet weld structure 29, U-rib and transverse diaphragm fillet weld structure 30, and U-rib and transverse diaphragm notched arc edge structure 31. The fillet weld angle of U-rib and bridge deck fillet weld structure 29 is 103°, and the fillet weld angle of U-rib and transverse diaphragm fillet weld structure 30 is 90°.

[0064] By employing a variable measuring probe 100, the magnetic memory signals of three specific structures in orthotropic plates are accurately measured, solving the problem of precise detection in areas prone to cracking in orthotropic plates and improving the identifiability of fatigue cracks. The equipment is quick to install, overcoming the challenge of limited operating space for testing instruments on steel box girders. It enables simultaneous acquisition of vertical and tangential signal data, improving the flexibility and effectiveness of fatigue crack detection in orthotropic steel box girders and reducing the missed detection rate. No sensors need to be installed on the monitored object, eliminating the need for extensive wiring. It can collect magnetic memory signals of the monitored object in real time within the steel box girder while vehicles are passing, minimizing interference between on-site measurements and normal bridge traffic. During testing, no treatment is needed to prevent steel surface corrosion; the probe simply scans the surface of the measurement area, eliminating the need for consumables such as strain gauges, wires, adhesives, sandpaper, and insulating glue required by conventional monitoring techniques, as well as the grinding process on the measurement point surface. Therefore, this invention has the advantages of zero wear and low measurement cost.

[0065] Example 2

[0066] like Figure 6As shown, a method for detecting fatigue cracks in orthotropic plates of steel box girders includes the following steps:

[0067] S1: Pre-treatment detection area.

[0068] S2: Place the measuring probe 100 in the detection area.

[0069] S3: Set the moving speed of the electric slide 11 based on the measurement path.

[0070] S4: Set the relative position of the electric slide rail 11 on the electric X-axis 13 and electric Z-axis 12 based on the measurement direction.

[0071] S5: Acquire magnetic field signals, obtain data files and graphic files based on the magnetic field signals, and obtain detection results based on the data files and graphic files.

[0072] In step S1, lines are drawn on the inspection area according to the preset scheme, including: drawing lines at the starting and ending points of the fillet weld measurement according to the preset length; and drawing lines on the area at the edge of the arc-shaped notch of the transverse diaphragm 28 according to the arc tangent scheme.

[0073] Specifically, such as Figure 5 , Figure 7 and Figure 8 As shown, lines are drawn at the starting and ending points of the fillet weld measurement according to the preset length.

[0074] Since fatigue weak points in orthotropic fillet weld structures often occur at the weld toes on both sides of the fillet weld, and the crack direction is along the weld direction, this invention innovatively proposes to use a first sensor 2 and a second sensor 3 at an angle to each other, and set them to measure the tangential Z magnetic memory signal perpendicular to the weld direction, and simultaneously measure the normal Y signal as evidence, which can effectively obtain crack information and improve the accuracy and measurement efficiency of crack identification.

[0075] Specifically, such as Figure 5 and Figure 9 As shown, lines are drawn in the area at the edge of the arc-shaped notch in the diaphragm 28 according to the arc tangent scheme.

[0076] Since fatigue cracks in orthotropic plates with arc-shaped notches are mostly in the normal direction of the notch edge, and a more effective method for measuring cracks on a plane is to make the sensor travel direction pass through the crack, the inner included angle of the sensor position fixer 4 is expanded to 180°, and the first sensor 2 and the second sensor 3 are respectively set to measure the tangential X-magnetic memory signal of two parallel paths that cross the potential crack, thus expanding the application range of the probe and improving its flexibility.

[0077] Specifically, such as Figure 7As shown, for the fillet weld between U-rib 26 and bridge deck 27, the marked area is located in the middle section of U-rib 26 between the two transverse diaphragms 28, with a length of more than 1 / 3 of the distance between the two transverse diaphragms 28; in this embodiment, it is 1m. Figure 8 As shown, for the fillet weld between U-rib 26 and transverse diaphragm 28, the marked area is set from the notch upwards to 1 / 2 the height of U-rib 26, which is 60mm in this embodiment. Figure 9 As shown, for the arc-shaped edges of the U-rib 26 and the diaphragm 28 notches, a circular arc tangent scheme is adopted, and the area of ​​1 / 2 of the arc-shaped notch edge of the diaphragm 28 is divided into at least 2 segments with tangent lines. The entire arc-shaped notch structure has at least 4 tangent segments.

[0078] In step S2, specifically, the probe scanning frame 200 is stably placed near the measurement location of the orthotropic plate inside the steel box girder.

[0079] Specifically, the included angle θ of the sensor position fixer 4 is adjusted so that the first one-way roller 8 and the second one-way roller 9 on the first fixed plane 5 and the second fixed plane 6 are in close contact with the planes on both sides of the measurement area.

[0080] Option 1: As Figure 5 As shown, the measuring probe 100 is placed at the fillet weld between the U-rib 26 and the bridge deck 27 inside the steel box girder, as... Figure 2 As shown, the included angle θ of the sensor position fixer 4 is adjusted to 103°, and the tangential Z signal direction of the first sensor 2 and the second sensor 3 is adjusted to be perpendicular to the roller travel direction.

[0081] Option 2: As Figure 5 As shown, the measuring probe 100 is placed at the fillet weld above the arc-shaped notch of the weld between the U-rib 26 and the transverse diaphragm 28 inside the steel box girder, as... Figure 2 As shown, adjust the inner angle θ of the sensor position fixer 4 to 90°, and adjust the tangential Z signal direction of the first sensor 2 and the second sensor 3 to be perpendicular to the roller travel direction.

[0082] Third option: such as Figure 5 As shown, the measuring probe 100 is placed at the arc-shaped edge of the notch between the U-rib 26 and the transverse diaphragm 28 inside the steel box girder, as... Figure 2 As shown, the included angle θ of the sensor position fixer 4 is adjusted to 180°, and the tangential Z signal direction of the first sensor 2 and the second sensor 3 is adjusted to the X direction, that is, parallel to the roller travel direction.

[0083] In step S3, specifically, control cabinet 15 provides speeds of 1, 2, and 3. All three speed settings can ensure measurement quality.

[0084] When the measurement path is relatively short, the slow setting, i.e., "level 1", can be selected. For example... Figure 5As shown, for example, when measuring the fillet weld structure 30 of the U-rib and the diaphragm and the arc-shaped edge structure 31 of the U-rib and the diaphragm notch, the control cabinet 15 knob is turned to "position 1", and the electric slide 11 will move at a constant speed of 30mm / s.

[0085] For longer measurement paths, medium or high speed settings can be selected. For example... Figure 5 As shown, for example, when measuring the fillet weld structure 29 between the U-rib and the bridge deck, turn the control cabinet 15 knob to "gear 2" or "gear 3", and the electric slide rail 11 will move at a constant speed of 50 mm / s or 65 mm / s.

[0086] In step S4, specifically, as follows: Figure 3 As shown, when the direction controller 16 knob is turned to the "left / right" position, the electric slide rail 11 moves along the electric X-axis 13; when the knob is turned to the "up / down" position, the electric slide rail 11 moves along the electric Z-axis 12. This controls the gimbal lever 10 to move the first sensor 2 and the second sensor 3 in a predetermined direction.

[0087] In step S5, specifically, as follows: Figure 4 As shown, before acquiring the magnetic field signal of the orthotropic plate structure of the steel box girder using the magnetic memory detector 300, the following steps are included:

[0088] Take out Figure 2 As shown in the diagram, with the Y-direction arrows of both sensors pointing upwards, click as shown. Figure 4 The calibration button 19 is shown; with the Z-direction arrows of the first sensor 2 and the second sensor 3 pointing upwards simultaneously, click the calibration button 19. This completes the calibration of the magnetic memory detector 300 and the measuring probe 100.

[0089] The magnetic memory detector 300 collects data at a preset frequency of 1000Hz. Figure 7 and Figure 8 The magnetic memory signal values ​​H in the normal Y and tangential Z directions of the fatigue structure 400 of the orthotropic plate of the steel box girder are shown. y and H z Magnetic memory signal mutation value K y and K z This yields a sequence data file and a graphic file containing information along the walking path. For example... Figure 10 As shown, the abrupt change value K of the magnetic memory signal of the fillet weld structure obtained by using the detection device and detection method of the present invention is given. z and K y The detection results image shows that in the range of 2300-2500 samples, K z The graph shows an abnormal fatigue crack pattern; correspondingly, K yThe graph also showed abrupt changes. When this occurs, additional data should be measured on-site immediately for confirmation.

[0090] The magnetic memory detector 300 collects data at a preset frequency of 1000Hz. Figure 9 The magnetic memory signal values ​​H in the normal Y and tangential X directions of the fatigue structure 400 of the orthotropic plate of the steel box girder shown are... y and H x Magnetic memory signal mutation value K y and K x This yields a sequence data file and a graphic file containing information along the walking path. For example... Figure 11 As shown, the magnetic memory signal value H is the value when a crack appears. x and H y The detection result diagram, that is, once H x It shows a deep, elongated funnel shape, while H y If the graphic shows a deep tangent line, then the arrow must cross the crack. In this case, the crack location can be confirmed on-site at the corresponding location based on the step length of the travel path.

[0091] The measured data files and graphic files are copied to the computer via the USB interface 24 on the magnetic memory detector 300.

[0092] After acquiring data and graphic files of the magnetic memory signals of the orthotropic plates of the steel box girder using the magnetic memory detector 300, the process includes: analyzing and processing the acquired data and graphic files; various results will occur during actual measurements, which need to be referenced. Figure 10 and Figure 11 A comprehensive assessment was conducted to obtain the detection results of fatigue cracks in the orthotropic plates of the steel box girder.

[0093] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A device for detecting fatigue cracks in orthotropic plates of steel box girders, characterized in that, include: The fatigue structure of the orthotropic plate of the steel box girder is equipped with a three-dimensional measurement probe and a probe scanning frame. The measurement probe is mechanically connected to the probe scanning frame via a universal joint rod. In the measurement probe, the outer corner of the sensor position fixation device is provided with an inward concave arc. The two ends of the sensor position fixation device are respectively provided with a first fixed plane and a second fixed plane. The included angle between the first fixed plane and the second fixed plane is 90° to 180°. A first sensor is provided on the first fixed plane and a second sensor is provided on the second fixed plane. The first sensor and the second sensor are electrically connected to a magnetic memory detector via probe wires. The first sensor and the second sensor can rotate 90° within the plane of the first fixed plane and the second fixed plane to switch between tangential Z signal or tangential X signal and measure synchronously with the normal Y signal.

2. The device for detecting fatigue cracks in orthotropic plates of steel box girders according to claim 1, characterized in that, The first fixed plane is provided with a first one-way roller, the second fixed plane is provided with a second one-way roller, and the first sensor and the second sensor are electrically connected to the magnetic memory detector through the probe line.

3. A device for detecting fatigue cracks in orthotropic plates of steel box girders according to claim 1 or 2, characterized in that, The first sensor and the second sensor are located between the first unidirectional roller and the second unidirectional roller.

4. A device for detecting fatigue cracks in orthotropic plates of steel box girders according to claim 1 or 2, characterized in that, When the included angle between the first fixed plane and the second fixed plane is 180°, the direction of the roller bearing is parallel to the line connecting the first sensor and the second sensor. When the included angle is 90°, the sensor's tangential Z signal is perpendicular to or parallel to the roller's traveling direction X. When they are parallel, the sensor's tangential Z signal is converted into a tangential X signal.

5. The device for detecting fatigue cracks in orthotropic plates of steel box girders according to claim 1, characterized in that, In the probe scanning frame, the bracket is connected to the electric X-axis, the electric X-axis is connected to the electric Z-axis, the electric Z-axis is equipped with an electric slide rail, the electric slide rail is connected to the universal joint rod and the control cabinet, the universal joint rod is connected to the measuring probe, and the control cabinet is connected to the direction controller and the 220V power supply.

6. A device for detecting fatigue cracks in orthotropic plates of steel box girders according to claim 1 or 5, characterized in that, The electric slide is electrically connected to the control cabinet, which controls the moving speed of the electric slide; the control cabinet is electrically connected to the direction controller, which controls the relative position of the electric slide on the electric X-axis and electric Z-axis.

7. The device for detecting fatigue cracks in orthotropic plates of steel box girders according to claim 1, characterized in that, In the fatigue structure of orthotropic plates in steel box girders, the U-ribs and bridge deck are connected to form a fillet weld structure between the U-ribs and bridge deck, and the U-ribs and diaphragms are connected to form a fillet weld structure between the U-ribs and diaphragms and a notched arc edge structure between the U-ribs and diaphragms.

8. A device for detecting fatigue cracks in orthotropic plates of steel box girders according to claim 1 or 7, characterized in that, The angle between the fillet weld between the U-rib and the bridge deck is 103°, and the angle between the fillet weld between the U-rib and the diaphragm is 90°.

9. A method for detecting fatigue cracks in orthotropic plates of steel box girders, comprising the detection device for detecting fatigue cracks in orthotropic plates of steel box girders as described in any one of claims 1-8, characterized in that, Includes the following steps: S1: Pre-treatment detection area; S2: Place the measuring probe in the detection area; S3: Set the moving speed of the electric slide based on the measurement path; S4: Set the relative position of the electric slide rail on the electric X-axis and electric Z-axis based on the measurement direction; S5: Acquire magnetic field signals, obtain data files and graphic files based on the magnetic field signals, and obtain detection results based on the data files and graphic files.

10. The method for detecting fatigue cracks in orthotropic plates of steel box girders according to claim 9, characterized in that, Step S2 includes: The measuring probe is placed at the fillet weld between the U-rib inside the steel box girder and the bridge deck. The inner angle of the sensor position fixer is adjusted to 103°. The tangential Z signal direction of the first and second sensors is perpendicular to the roller travel direction. Alternatively, the measuring probe can be placed at the fillet weld above the arc-shaped notch of the weld between the U-rib and the transverse diaphragm inside the steel box girder, and the inner angle of the sensor position fixer can be adjusted to 90°, with the tangential Z-signal direction of the first and second sensors perpendicular to the roller travel direction. Alternatively, the measuring probe can be placed on the arc-shaped edge of the U-rib and the notch of the transverse diaphragm inside the steel box girder, and the inner angle of the sensor position fixer can be adjusted to 180°. The tangential Z-signal directions of the first and second sensors are parallel to the roller travel direction.

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