Concrete reinforcement nondestructive testing device and testing method

Abstract

The invention relates to a concrete reinforcement nondestructive testing device and a testing method. The device comprises a controller, a display screen, a manual knob, a handle, an adjustable knob, a crank, a rotating shaft, a probe disc and a protective cover, wherein a control circuit and a rechargeable battery are arranged in the controller, and man-machine interaction is carried out on a display screen above the controller; the manual knob is arranged on the left side of the controller; the handle is arranged above the controller and is connected with the crank through the adjustable knob; the rotating shaft is connected with the other side of the crank; the rotating shaft is embedded into the protective cover, and meanwhile, the probe disc is fixed in the rotating shaft. The strong magnets with different surface magnetisms are arranged to excite different magnetic fields, so that signals transmitted to the sensor by the reinforcing steel bar are different, different magnetic field data at the same position can be obtained at the same time in a rotary scanning mode, and then the position and the burying depth of the reinforcing steel bar are obtained by measuring the distance between the probe disc and concrete.

Description

Technical Field

[0001] The present invention relates to the technical field of nondestructive testing, and in particular to a nondestructive testing device and method for concrete reinforcement bars. Background Art

[0002] As modern building structures evolve toward higher heights, larger spans, and more specialized shapes, accurate inspection of the position, cover thickness, diameter, and corrosion status of rebar, the core load-bearing component of concrete structures, has become crucial for ensuring project safety. Driven by standards such as the "Concrete Structure Construction Quality Acceptance Code," building quality supervision is shifting from traditional "results-based acceptance" to "full-cycle control," placing an urgent need for digital, non-destructive, and high-precision inspection technologies.

[0003] Early detection relies primarily on traditional methods such as manual visual inspection and caliper measurement, which are subject to bottlenecks such as low efficiency (single-point detection takes ≥5 minutes), high subjectivity (human interpretation error rate >15%), and an inability to identify internal defects (such as misaligned rebar). For example, in bridge engineering, traditional mechanical extensometers are susceptible to vibration interference, resulting in deviations of up to 20% in rebar stress data, seriously hindering structural safety assessments.

[0004] In recent years, nondestructive testing methods, particularly electromagnetic induction technology, have rapidly developed. By analyzing rebar parameters through magnetic field variations, they have enabled non-destructive, highly efficient, and intelligent testing. However, significant challenges remain in complex construction scenarios. Firstly, dense rebar meshes or overlapping layers of rebar can cause magnetic field signal aliasing, making it difficult to accurately distinguish structural layers. For example, when the spacing between two layers of rebar is less than 100mm, the error rate can exceed 30%. Secondly, electromagnetic interference sources on the construction site, such as welding equipment and pre-buried metal pipelines, can easily cause signal anomalies, leading to the risk of misjudgment of positioning offsets of 10mm or more. Summary of the Invention

[0005] In order to solve the technical problems existing in the prior art, the present invention provides a non-destructive testing device and method for concrete steel bars. By setting strong magnets with different surface magnetism to stimulate different magnetic fields, the signals transmitted from the steel bars to the sensor are different. By rotating scanning, different magnetic field data at the same position can be obtained simultaneously. Then, by measuring the distance between the probe disk and the concrete, the position of the steel bars and the burial depth can be obtained.

[0006] The device of the present invention adopts the following technical scheme to be implemented: a concrete steel bar non-destructive testing device, including a controller, a display screen, a manual knob, a handle, an adjustable knob, a crank, a rotating shaft, a probe disk, and a protective cover; wherein, a control circuit and a rechargeable battery are placed in the controller, and human-computer interaction is performed on the display screen above it; the manual knob is arranged on the left side of the controller; the handle is installed above the controller and is connected to the crank through the adjustable knob; the rotating shaft is connected to the other side of the crank; the rotating shaft is embedded in the protective cover, and the probe disk is fixed in the rotating shaft.

[0007] Furthermore, the manual knob is used to manually adjust the position of the probe disc; and the adjustable knob is used to adjust the angle of the crank.

[0008] Furthermore, the rotating shaft includes a fixed shaft, a servo, a driving wheel, a steering wheel, a bearing, a slip ring, and a positioning pin; wherein, the fixed shaft is embedded in the limiting groove of the protective cover, the servo outputs power to the driving wheel, and the steering wheel changes the direction of the torque; the slip ring is used to transmit signals between the rotating part and the stationary part, and at the same time fixes the probe disk with the positioning pin.

[0009] Furthermore, the probe disk is in a four-leaf shape, and the end portion is composed of a strong magnet and a sensor; a strong magnet compartment is placed outside the strong magnet, and a flip cover is provided on the outside.

[0010] The method of the present invention is implemented by the following technical solutions: a method for nondestructive testing of concrete reinforcement bars. Before testing, the device is lifted by a handle and the adjustable knob is adjusted to keep the probe disk level with the wall to be tested. The display screen is operated to enter scanning mode, and the steering gear is activated to drive the probe disk to rotate. At this time, four groups of detection units simultaneously detect the concrete below based on their positions. After four groups of signal data are obtained after one rotation, the number of steel bars and the buried depth are output on the display screen. The specific process also includes the following steps:

[0011] S1. The magnetic field formula of a cylindrical strong magnet along the central axis is as follows:

[0012]

[0013] Among them, B r is the surface magnetic size, r0 is the radius, and h is the height of the magnet. By determining the model of the strong magnet and the position of the measurement point, the magnetic induction intensity of the Z-axis component can be known.

[0014] S2. For the X and Y axis directions, the empirical formula is obtained by curve fitting as follows:

[0015]

[0016] Among them, A1 is the magnetic field strength of the permanent magnet, A2 is the magnetic field strength of the steel bar magnetization, t1 is the magnetic field attenuation coefficient of the permanent magnet, x is the vertical measurement distance, and t2 is the magnetic field attenuation coefficient of the steel bar magnetization. This formula can be used to determine the horizontal component of the cylindrical strong magnet.

[0017] S3. When there is no steel bar under the device, the first sensor placed directly under the strong magnet only obtains the magnetic field signal B'1 in the Z direction, and the second sensor placed directly under the non-strong magnet obtains the magnetic field signal B'2 including the magnitude of the X and Z directions and the magnetic field angle at this time; when there is a steel bar under the device, the spatial magnetic field B is respectively the strong magnet magnetic field B M and the steel bar excitation magnetic field B Reb , and then we get:

[0018] B′1=B M,z1 +B Reb,z1 and

[0019] Among them, B M,z1 is the Z-axis component of the permanent magnet magnetic field of the first sensor, B Reb,z1 is the Z-axis component of the second sensor magnetizing magnetic field, B′ 2,x is the X-axis signal of the second sensor, B M,x2 is the X-axis component of the magnetic field of the second sensor permanent magnet, B Reb,x2 is the X-axis component of the second sensor magnetizing magnetic field, B′ 2,z is the Z-axis signal of the second sensor, B M,z2 is the Z-axis component of the magnetic field of the second sensor permanent magnet, B Reb,z2 is the Z-axis component of the magnetizing magnetic field of the second sensor;

[0020] S4. When n steel bars are stacked under the detection unit, the n+1 magnetic fields generated together constitute the detection signal of the sensor, which is manifested as an increase in the signal intensity of the first sensor directly under the strong magnet and an increase in the signal angle of the second sensor directly under the non-strong magnet.

[0021] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0022] 1. The present invention uses strong magnets with different surface magnetism to stimulate different magnetic fields, so that the signals transmitted from the steel bars to the sensor are different. By rotating scanning, different magnetic field data at the same position can be obtained simultaneously. Then, by measuring the distance between the probe disk and the concrete, the position of the steel bar and the burial depth can be obtained.

[0023] 2. The present invention adopts a static magnetic field detection mode, which suppresses external electromagnetic wave interference, such as power frequency noise and wireless signals, through a steady-state magnetic field environment, significantly improving the reliability of detection data in complex construction scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural diagram of the present invention;

[0025] Figure 2 It is a structural diagram of the rotating shaft of the present invention;

[0026] Figure 3 It is a structural diagram of the probe disc of the present invention;

[0027] Figure 4 It is a schematic diagram of the present invention;

[0028] In the figure, 1 is the controller, 2 is the display screen, 3 is the manual knob, 4 is the handle, 5 is the adjustable knob, 6 is the crank, 7 is the rotating shaft, 8 is the probe disk, 9 is the protective cover, 10 is the sensor, 11 is the strong magnet, 71 is the fixed shaft, 72 is the servo, 73 is the driving wheel, 74 is the steering wheel, 75 is the bearing, 76 is the slip ring, 77 is the positioning pin, 91 is the flip cover, and 92 is the strong magnet compartment. DETAILED DESCRIPTION

[0029] The present invention will be described in further detail below with reference to the embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0030] Example

[0031] like Figure 1 As shown, this embodiment is a non-destructive testing device for concrete steel bars, including a controller 1, a display screen 2, a manual knob 3, a handle 4, an adjustable knob 5, a crank 6, a rotating shaft 7, a probe disk 8, and a protective cover 9; wherein, a control circuit and a rechargeable battery are placed in the controller, and human-computer interaction is performed on the display screen above it; the manual knob is arranged on the left side of the controller; the handle is installed above the controller and is connected to the crank through the adjustable knob; the rotating shaft is connected to the other side of the crank; the rotating shaft is embedded in the protective cover, and the probe disk is fixed in the rotating shaft.

[0032] Specifically, in this embodiment, the manual knob is used to manually adjust the position of the probe disc; and the adjustable knob is used to adjust the angle of the crank.

[0033] like Figure 2 As shown, in this embodiment, the rotating shaft includes a fixed shaft 71, a servo 72, a driving wheel 73, a steering wheel 74, a bearing 75, a slip ring 76, and a positioning pin 77; wherein, the fixed shaft is embedded in the limiting groove of the protective cover, the servo outputs power to the driving wheel, and the steering wheel changes the direction of the torque; the slip ring is used to transmit signals between the rotating part and the stationary part, and at the same time fixes the probe disk with the positioning pin.

[0034] like Figure 3 As shown, in this embodiment, the probe disc is in a four-leaf shape, and the end portion is composed of a strong magnet 11 and a sensor 10; a strong magnet compartment 92 is placed outside the strong magnet, and a flip cover 91 is provided on the outside.

[0035] Specifically, four groups of detection units consisting of strong magnets and sensors are placed on the probe disk, and the probe disk is fixed to the rotating shaft with positioning pins. When performing detection tasks, the rotating shaft drives the probe disk to rotate, and the detection unit is used to record the position and signal size to determine the position and burial depth of the steel bars below.

[0036] Specifically, in this embodiment, the strong magnets are cylindrical, have the same physical dimensions, and have different surface magnetisms, and are all axially magnetized.

[0037] Specifically, in this embodiment, the sensor is a three-dimensional linear Hall effect sensor, which can obtain the magnetic induction magnitude of the X, Y, and Z axes and obtain the magnetic field angle at that point.

[0038] Specifically, in this embodiment, the probe plate, the protective cover and the flip cover are all made of plastic.

[0039] like Figure 4 As shown, in this embodiment, a method for nondestructive testing of concrete reinforcement is based on the above-mentioned nondestructive testing device for concrete reinforcement. Before testing, the method lifts the device by a handle and adjusts the adjustable knob to keep the probe disk level with the wall to be tested. The display screen is operated to enter scanning mode, and the servo is activated to drive the probe disk to rotate. At this time, four groups of detection units simultaneously detect the concrete below based on their positions. After four groups of signal data are obtained after one rotation, the number of steel bars and the buried depth are output on the display screen. The specific process also includes the following steps:

[0040] S1. The magnetic field formula of a cylindrical strong magnet along the central axis is as follows:

[0041]

[0042] Among them, B r is the surface magnetic size, r0 is the radius, and h is the height of the magnet. By determining the model of the strong magnet and the position of the measurement point, the magnetic induction intensity of the Z-axis component can be known.

[0043] S2. For the X and Y axis directions, the empirical formula is obtained by curve fitting as follows:

[0044]

[0045] Among them, A1 is the magnetic field strength of the permanent magnet, A2 is the magnetic field strength of the steel bar magnetization, t1 is the magnetic field attenuation coefficient of the permanent magnet, x is the vertical measurement distance, and t2 is the magnetic field attenuation coefficient of the steel bar magnetization. This formula can be used to approximately determine the horizontal component size of the cylindrical strong magnet;

[0046] S3. When there is no steel bar under the device, the sensor placed directly under the strong magnet (called the first sensor) only obtains the magnetic field signal B1 in the Z direction.′ The sensor directly below the non-strong magnet (called the second sensor) obtains the magnetic field signal B2 ′ Including the size of the X and Z directions and the magnetic field angle at this time; when there are steel bars under the device, the spatial magnetic field B is the strong magnetic field B M and the steel bar excitation magnetic field B Reb , and then we get:

[0047]

[0048] Among them, B M,z1 is the Z-axis component of the permanent magnet magnetic field of the first sensor, B Reb,z1 is the Z-axis component of the second sensor magnetizing magnetic field, B′ 2,x is the X-axis signal of the second sensor, B M,x2 is the X-axis component of the magnetic field of the second sensor permanent magnet, B Reb,x2 is the X-axis component of the second sensor magnetizing magnetic field, B′ 2,z is the Z-axis signal of the second sensor, B M,z2 is the Z-axis component of the magnetic field of the second sensor permanent magnet, B Reb,z2 is the Z-axis component of the magnetizing magnetic field of the second sensor;

[0049] S4. When n steel bars are stacked under the detection unit, the n+1 magnetic fields generated together constitute the detection signal of the sensor, which is manifested as an increase in the signal intensity of the first sensor directly under the strong magnet and an increase in the signal angle of the second sensor directly under the non-strong magnet.

[0050] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A nondestructive testing device for concrete reinforcement, characterized in that: It includes a controller, a display screen, a manual knob, a handle, an adjustable knob, a crank, a rotating shaft, a probe disk, and a protective cover. The control circuit and the rechargeable battery are placed in the controller, and the human-computer interaction is performed on the display screen above it. The manual knob is set on the left side of the controller. The handle is installed on the top of the controller and is connected to the crank through the adjustable knob. The rotating shaft is connected to the other side of the crank. The rotating shaft is embedded in the protective cover, and the probe disk is fixed in the rotating shaft.

2. A nondestructive testing device for concrete reinforcement according to claim 1, characterized in that: The manual knob is used to manually adjust the position of the probe disc; the adjustable knob is used to adjust the angle of the crank.

3. The nondestructive testing device for concrete reinforcement according to claim 1, characterized in that: The rotating shaft includes a fixed shaft, a servo, a driving wheel, a steering wheel, a bearing, a slip ring, and a positioning pin; among them, the fixed shaft is embedded in the limit groove of the protective cover, the servo outputs power to the driving wheel, and the steering wheel changes the direction of torque; the slip ring is used to transmit signals between the rotating parts and the stationary parts, and at the same time fixes the probe disk with the positioning pin.

4. The nondestructive testing device for concrete reinforcement according to claim 1, characterized in that: The probe disk is in a four-leaf shape, and the end is composed of a strong magnet and a sensor; a strong magnet compartment is placed outside the strong magnet, and a flip cover is provided on the outside.

5. The nondestructive testing device for concrete reinforcement according to claim 3, characterized in that: Four sets of detection units consisting of strong magnets and sensors are placed on the probe disk. The probe disk is fixed to the rotating shaft with positioning pins. When performing detection tasks, the rotating shaft drives the probe disk to rotate. The detection unit is used to record the position and signal size to determine the position and burial depth of the steel bars below.

6. The nondestructive testing device for concrete reinforcement according to claim 4, characterized in that: Strong magnets are cylindrical in shape, with the same physical dimensions and different surface magnetism, and are all axially magnetized.

7. The nondestructive testing device for concrete reinforcement according to claim 4, characterized in that: The sensor is a three-dimensional linear Hall effect sensor, which is used to obtain the magnetic induction size of the X, Y, and Z axes and obtain the magnetic field angle at that point.

8. The nondestructive testing device for concrete reinforcement according to claim 4, characterized in that: The probe plate, protective cover and flip cover are made of plastic.

9. A detection method based on the concrete reinforcement nondestructive testing device according to claim 1, characterized in that: Before testing, lift the device by the handle and adjust the adjustable knob to keep the probe disk level with the wall to be tested. Operate the display screen to enter scanning mode, and activate the servo to drive the probe disk to rotate. At this time, the four detection units simultaneously detect the concrete below based on their positions. After obtaining four sets of signal data after one rotation, the number of steel bars and the buried depth are output on the display screen. The specific process also includes the following steps: S1. The magnetic field formula of a cylindrical strong magnet along the central axis is as follows: Among them, B r is the surface magnetic size, r0 is the radius, and h is the height of the magnet. By determining the model of the strong magnet and the position of the measurement point, the magnetic induction intensity of the Z-axis component can be known. S2. For the X and Y axis directions, the empirical formula is obtained by curve fitting as follows: Among them, A1 is the magnetic field strength of the permanent magnet, A2 is the magnetic field strength of the steel bar magnetization, t1 is the magnetic field attenuation coefficient of the permanent magnet, x is the vertical measurement distance, and t2 is the magnetic field attenuation coefficient of the steel bar magnetization. This formula can be used to determine the horizontal component of the cylindrical strong magnet. S3. When there is no steel bar under the device, the first sensor placed directly under the strong magnet only obtains the magnetic field signal B'1 in the Z direction, and the second sensor placed directly under the non-strong magnet obtains the magnetic field signal B'2 including the magnitude of the X and Z directions and the magnetic field angle at this time; when there is a steel bar under the device, the spatial magnetic field B is respectively the strong magnet magnetic field B M and the steel bar excitation magnetic field B Reb , and then we get: B′1=B M,z1 +B Reb,z1 and Among them, B M,z1 is the Z-axis component of the permanent magnet magnetic field of the first sensor, B Reb,z1 is the Z-axis component of the second sensor magnetizing magnetic field, B′ 2,x is the X-axis signal of the second sensor, B M,x2 is the X-axis component of the magnetic field of the second sensor permanent magnet, B Reb,x2 is the X-axis component of the second sensor magnetizing magnetic field, B′ 2,z is the Z-axis signal of the second sensor, B M,z2 is the Z-axis component of the magnetic field of the second sensor permanent magnet, B Reb,z2 is the Z-axis component of the magnetizing magnetic field of the second sensor; S4. When n steel bars are stacked under the detection unit, the n+1 magnetic fields generated together constitute the detection signal of the sensor, which is manifested as an increase in the sensor signal intensity directly under the strong magnet and an increase in the sensor signal angle directly under the non-strong magnet.

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