Steel cable damage detection system and method based on eddy current effect

Abstract

The invention discloses a steel cable damage detection system and method based on an eddy current effect, and aims to effectively detect damage conditions of ferromagnetic materials such as steel strands and parallel steel wire cables. The steel cable damage detection system comprises a buckling sensor, an excitation module, an electromagnetic signal acquisition module, a data processing module and a data analysis device. Wherein the buckling type sensor is mounted on a steel cable and is provided with an exciting coil and a signal acquisition coil; the excitation module interface is connected with the excitation coil, and the electromagnetic signal acquisition module interface is connected with the signal acquisition coil. According to the steel cable damage detection method, sinusoidal current is generated in the excitation coil through the excitation module, so that eddy current is induced in the steel cable. Then, the electromagnetic signal acquisition module describes the damage condition of the steel cable by acquiring a voltage signal induced by a signal acquisition coil. The detection method has the advantages of high precision, strong repeatability and rapid detection, and can accurately identify the damage of the steel cable.

Description

Technical Field

[0001] The present invention relates to the field of non-destructive testing, and particularly to a method and system for detecting steel cable damage based on the eddy current effect, which is applicable to fields such as long-span bridge engineering and large-scale building engineering structures. Background Art

[0002] With the continuous development of the economy and the construction industry, cable-stayed bridges, suspension bridges and other cable bridges have been widely used in traffic construction. As the main load-bearing structure of cable bridges, the safety of steel cables has received extensive attention. Factors such as overload phenomena, rapid temperature changes, and complex external environments may cause the aging and cracking of the PE sheath of steel cables, resulting in corrosion of the steel cables under the action of air and rain, and further causing broken wire damage inside the steel cables. The occurrence of broken wire damage is extremely destructive to steel cables, which may lead to a reduction in their load-bearing capacity, cause stress concentration phenomena, and then affect the service performance of steel cables, and even have a significant impact on the safety of the entire bridge. Therefore, it has become crucial to regularly detect the damage of steel cables, and the detection of broken wire damage of steel cables is also one of the key research points in the field of non-destructive testing. Therefore, achieving accurate and convenient detection of steel cable damage has become the focus of many studies.

[0003] In recent years, eddy current testing technology has gradually matured, and the eddy current effect is used to detect the damage condition. This technology has the advantages of high precision and rapid detection. However, most current sensor devices are too complex, the detection system lacks flexibility, the device volume is large, and the precision is low.

[0004] In summary, although there are many current studies on methods for detecting steel cable damage, there are still challenges in the efficient detection of steel cable damage. The device needs to be further optimized, the flexibility of the detection system also needs to be improved, and at the same time, the device volume needs to be reduced. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the present invention provides a system and method for detecting steel cable damage based on the eddy current effect, so as to optimize the steel cable damage detection system and sensors.

[0006] The present invention discloses a steel cable damage detection system based on the eddy current effect, including a snap-on sensor, an excitation module, an electromagnetic signal acquisition module, a data processing module and a data analysis device; The snap-on sensor includes a snap-on skeleton and an excitation coil and a signal acquisition coil arranged on the snap-on skeleton. The snap-on sensor is installed on the steel cable to be tested; the excitation coil is connected to the excitation module through an excitation module connection line, and the signal acquisition coil is connected to the electromagnetic signal acquisition module through a signal acquisition module connection line; The data processing module is connected to the excitation module and the electromagnetic signal acquisition module, and is used to collect the induced voltage of the signal acquisition coil and the excitation current of the excitation coil in real time, perform calculations, calculate the magnitudes of the equivalent series resistance and the equivalent series reactance, and upload them through the wireless communication module; The data analysis device receives the data uploaded by the wireless communication module in real time, and draws charts of the equivalent series resistance value and the equivalent series reactance value varying with the detection position.

[0007] As a further improvement of the present invention, both the excitation coil and the signal acquisition coil are single-turn and are PCB coils; the excitation coil is composed of two symmetrically arranged coils, and is connected by enameled wire to ensure that the current directions of the two excitation coils are opposite; the signal acquisition coil is a single coil and is located on the middle plane of the central axis of the two excitation coils; the snap-on skeleton is made of high-strength resin material and is snap-fitted to achieve the snap-on of the two.

[0008] As a further improvement of the present invention, the excitation module, the electromagnetic signal acquisition module and the data processing module are integrated into a single single-chip microcomputer.

[0009] As a further improvement of the present invention, the excitation frequency of the excitation module is adjusted within the range of 1 KHz to 200 KHz.

[0010] As a further improvement of the present invention, the electromagnetic signal acquisition module is composed of two-stage amplifier circuits and is used to amplify the signal, with a maximum amplification factor of 1 to 1,000,000 times.

[0011] As a further improvement of the present invention, the data analysis device can configure different baud rates and display the data uploaded by the data processing module through the wireless communication module in real time.

[0012] As a further improvement of the present invention, the steel cable damage detection system is applicable to ferromagnetic steel cables, including steel stranded wires and parallel wire cables, to characterize the damage degree.

[0013] The present invention also discloses a steel cable damage detection method based on the eddy current effect, including: Step 1: Install a snap-on sensor on the steel cable. The excitation coil of the snap-on sensor is connected to the interface of the excitation module, and the signal acquisition coil of the snap-on sensor is connected to the electromagnetic signal acquisition module; Step 2: Configure the excitation module, select an appropriate excitation frequency to download the program to provide a sine excitation of the corresponding frequency; Step 3: Configure the electromagnetic signal acquisition module and select an appropriate amplification factor; Step 4: Configure the data processing module and install the wireless communication module; the data processing module processes the collected data, calculates the equivalent series resistance value and the equivalent series reactance value, and uploads them to the data analysis device through the wireless communication module; Step 5: Configure the data analysis device, install the wireless communication module, select an appropriate baud rate, and receive the equivalent series resistance value and the equivalent series reactance value transmitted by the data processing module; Step 6: By moving the snap-on sensor at a constant speed, the induced voltage signal of the signal acquisition coil and the excitation current signal of the excitation coil are collected in real time. The data analysis device displays the data in real time and shows the relationship curve between the data and the displacement; Step 7: Describe the damage condition of the stay cable by analyzing the measured equivalent series resistance value and equivalent series reactance value.

[0014] Implementing this cable damage detection system and method based on the eddy current effect of the present invention has the following beneficial effects: 1. The cable damage detection system based on the eddy current effect of the present invention has the advantages of high integration and high detection accuracy. This system provides an adjustable excitation current frequency and a received signal amplification factor, and at the same time realizes the miniaturization of the overall device, and has excellent cable damage detection capabilities.

[0015] 2. The snap-on sensor of the present invention has a unique structure, and both the excitation coil and the signal acquisition coil are composed of single-turn coils. The excitation coil consists of two parts with opposite current directions to achieve magnetic field difference. This sensor structure has powerful detection capabilities and high precision. At the same time, the number of coil turns is extremely low, it is easy to install, has low power consumption, is structurally miniaturized, and simplifies the operation process.

[0016] 3. The present invention can simultaneously obtain two signal values that accurately characterize the cable damage, enhancing the reliability of cable damage detection. There is no need to perform secondary analysis on the derivative information received by the signal acquisition coil, and the damage condition of the stay cable can be directly determined by observing the changes in the current equivalent series resistance value or equivalent series reactance value.

[0017] 4. This detection method is easy to operate, has powerful selectivity, a wide range of applications, and high repeatability. The detection curves for the same type of damage have extremely high repeatability. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is the overall installation schematic diagram of the cable damage detection system based on the eddy current effect disclosed by the present invention; Figure 2 It is the schematic sectional view of the snap-on sensor disclosed by the present invention; Figure 3 It is the working flow chart of the single-chip microcomputer disclosed by the present invention; Figure 4This is the flowchart of the steel cable damage detection method based on the eddy current effect disclosed by the present invention.

[0019] In the figure: 1. Steel cable; 2. Snap-on sensor; 3. Single-chip microcomputer; 4. Data analysis device; 5. Excitation coil; 6. Signal acquisition coil; 7. Excitation module connection line; 8. Signal acquisition module connection line; 9. Wireless communication module; 10. PCB board; 11. Enameled wire; 12. Snap-on skeleton. Specific embodiments

[0020] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0021] To better understand the purpose, structure and function of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings.

[0022] As Figure 1 , 2 shown, the present invention provides a steel cable damage detection system based on the eddy current effect, including: a snap-on sensor 2, a single-chip microcomputer 3 and a data analysis device 4; the snap-on sensor 2 includes a snap-on skeleton 12 and an excitation coil 5 and a signal acquisition coil 6 installed on the snap-on skeleton 12, the single-chip microcomputer 3 includes an excitation module, an electromagnetic signal acquisition module, a data processing module and a wireless communication module 9, the snap-on sensor 2 is installed on the steel cable 1 to be measured, the excitation coil 5 is connected to the excitation module through the excitation module connection line 7, and the signal acquisition coil 6 is connected to the electromagnetic signal acquisition module through the signal acquisition module connection line 8; the data processing module is connected to the excitation module and the electromagnetic signal acquisition module. Specifically: Install the snap-on sensor 2 on the steel cable 1, connect the excitation coil 5 to the excitation module of the single-chip microcomputer 3 through the excitation module connection line 7, and connect the signal acquisition coil 6 to the electromagnetic signal acquisition module of the single-chip microcomputer 3 through the signal acquisition module connection line 8. Install the wireless communication module 9 on the single-chip microcomputer 3, and adjust the excitation module on the single-chip microcomputer 3 to an appropriate excitation frequency and load the program. Adjust the adjustable resistor of the signal acquisition module on the single-chip microcomputer 3 to configure an appropriate amplification factor. The data analysis device 4 is externally connected to the same wireless communication module 9 to realize data communication and upload.

[0023] In the above implementation, preferably, the excitation module connection line 7 and the signal acquisition module connection line 8 are designed as RF cables to better resist interference and improve the detection effect.

[0024] In the above embodiments, preferably, the snap-on sensor 2 is fitted as closely as possible to the steel cable 1 so that the two are coaxial to improve the detection accuracy.

[0025] The structure of the snap-on sensor is as Figure 2 shown, including an excitation coil 5, a signal acquisition coil 6, a PCB skeleton 10, an enameled wire 11, and a snap-on skeleton 12. Both the excitation coil 5 and the signal acquisition coil 6 are single-turn PCB coils. The excitation coil 5 is composed of two symmetrically arranged coils, which are connected by an enameled wire 11 to ensure that their excitation current directions are opposite, forming a differential magnetic field, thereby weakening the influence of the primary magnetic field on the detection result; the signal acquisition coil 6 is a single coil and is located on the middle plane of the central axis of the two excitation coils. The snap-on skeleton 12 is made of a high-strength resin material and realizes the snap-on of the two in a snap-fastening manner.

[0026] In the above invention, the working process of the single-chip microcomputer is as Figure 3 shown. The DAC module of the MCU is used to provide the excitation current, which is amplified by the current induction amplifier to provide a sinusoidal excitation for the excitation coil. At the same time, the sinusoidal excitation current is fed back to the MCU, and the magnitude of the excitation current is obtained through ADC conversion to form the entire excitation module. The signal acquisition coil is used to collect the induced voltage, and the voltage value is input into the first-stage amplification circuit for the first-stage amplification, and the adjustable amplification factor is 1 - 1000 times. After amplification, it enters the second-stage amplification circuit, and the amplification factor can be adjusted to 1 - 1000 times. After the second-stage amplification, it enters the MCU. The magnitude of the induced voltage is obtained through the ADC conversion module to form the entire signal acquisition module. Corresponding operations are performed inside the MCU to calculate the equivalent series resistance value and the equivalent series reactance value. After calculation, quadrature demodulation and smoothing filtering are performed to filter out interference signals and noise, and the data is packed and sent to the wireless communication module 9 to form the entire data processing module. Subsequently, the wireless transmission module sends the data to the data analysis device 4 to realize the transmission and analysis of the data.

[0027] As Figure 4 shown, the present invention provides a method for detecting steel cable damage based on the eddy current effect. This detection method is realized based on the above-mentioned stay cable damage detection system; this detection method is not only applicable to the damage characterization of steel strand cables and parallel wire cables, but also applicable to the damage characterization of other ferromagnetic material steel cables. The specific steps for steel cable damage detection are as follows: S1: Use a small knife to remove the outer paint layer at both ends of the enameled wire of the snap-on sensor 2 and perform tin plating treatment, then connect the upper and lower excitation coils 5 to achieve reverse differential of the excitation current. Install the snap-on sensor 2 on the steel cable 1, ensuring their coaxiality as much as possible and making them fit as closely as possible. Connect the excitation coil 5 to the excitation module interface of the single-chip microcomputer 3 through a radio frequency cable, and connect the signal acquisition coil 6 to the receiving module interface of the single-chip microcomputer 3.

[0028] S2: Configure the electromagnetic signal acquisition module, and select an appropriate amplification factor by adjusting the adjustable resistance values of the first-stage amplification circuit and the second-stage amplification circuit.

[0029] S3: Configure the excitation module, select an appropriate excitation frequency, and set the excitation frequency to an appropriate value in the MCU control program. Connect to the single-chip microcomputer 3 through STLink and download the written program to provide a sinusoidal excitation current with an appropriate frequency.

[0030] S4: Configure the data processing module and install the wireless communication module 9. Process the collected data through the main control program, calculate the equivalent series resistance value and the equivalent series reactance value, perform quadrature demodulation and smoothing filtering to filter out interference and noise as much as possible to ensure the integrity of the detection signal, and upload it to the data analysis device 4 through the wireless communication module 9.

[0031] S5: Configure the data analysis device 4, which is a self-written host computer installed on the computer and can select different baud rates. When performing steel cable damage detection, connect the USB socket of the computer to another wireless communication module 9 and select an appropriate baud rate on the host computer. Then, click the start acquisition button to receive the equivalent series resistance value and the equivalent series reactance value transmitted by the data processing module.

[0032] S6: On the premise of ensuring the coaxiality of the steel cable 1 and the snap-on sensor 2, move the snap-on sensor 2 at a constant speed. The single-chip microcomputer 3 collects the induced voltage signal of the signal acquisition coil 6 and the excitation current signal of the excitation coil 5 in real time. The data analysis device 4 displays the data in real time and shows the relationship curve between the data and the displacement.

[0033] S7: By analyzing the measured equivalent series resistance value and the equivalent series reactance value, the damage condition of the steel cable can be described in detail, and the effective characterization of the steel cable damage can be achieved. The changes in the equivalent series resistance value and the equivalent series reactance value can reflect the damage degree and location of the steel cable, and then help to determine the type and severity of the damage. By analyzing these parameters, important information about the health status of the stay cable can be provided, providing a scientific basis for the detection and maintenance of the steel cable.

[0034] Components not described in detail in this article are existing technologies.

[0035] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A steel cable damage detection system based on the eddy current effect, characterized in that It includes a snap-on sensor, an excitation module, an electromagnetic signal acquisition module, a data processing module and a data analysis device; The snap-on sensor includes a snap-on skeleton, an excitation coil and a signal acquisition coil arranged on the snap-on skeleton. The snap-on sensor is installed on the steel cable to be measured. The excitation coil is connected to the excitation module through an excitation module connection wire, and the signal acquisition coil is connected to the electromagnetic signal acquisition module through a signal acquisition module connection wire; The data processing module is connected to the excitation module and the electromagnetic signal acquisition module, and is used for real-time collecting the induced voltage of the signal acquisition coil and the excitation current of the excitation coil, and performing calculations, calculating the magnitudes of the equivalent series resistance and the equivalent series reactance, and uploading them through a wireless communication module; The data analysis device receives the data uploaded by the wireless communication module in real time, and draws charts of the equivalent series resistance value and the equivalent series reactance value changing with the detection position.

2. The steel cable damage detection system based on the eddy current effect according to claim 1, wherein Both the excitation coil and the signal acquisition coil are single-turn and are made of PCB coils. The excitation coil is composed of two symmetrically arranged coils, which are connected by enameled wires to ensure that the current directions of the two excitation coils are opposite. The signal acquisition coil is a single coil and is located on the middle plane of the central axis of the two excitation coils. The snap-on skeleton is made of a high-strength resin material and is snap-fitted to achieve the snap-on of the two.

3. The steel cable damage detection system based on the eddy current effect according to claim 1, characterized in that, The excitation module, the electromagnetic signal acquisition module and the data processing module are integrated into a single single-chip microcomputer.

4. The steel cable damage detection system based on the eddy current effect according to claim 1, characterized in that The excitation frequency of the excitation module is adjusted within the range of 1KHz to 200KHz.

5. The steel cable damage detection system based on the eddy current effect according to claim 1, characterized in that The electromagnetic signal acquisition module is composed of two-stage amplifier circuits and is used to amplify the signal.

6. The steel cable damage detection system based on the eddy current effect according to claim 1, characterized in that The data analysis device can configure different baud rates and display the data uploaded by the data processing module through the wireless communication module in real time.

7. The steel cable damage detection system based on the eddy current effect according to claim 1, characterized in that The steel cable damage detection system is applicable to characterizing the damage degree of ferromagnetic steel cables, including stranded steel wires and parallel wire ropes.

8. A detection method for a steel cable damage detection system based on the eddy current effect as described in any one of claims 1 to 7, characterized in that, It includes: Step 1: Install a snap-on sensor on the steel cable. The excitation coil of the snap-on sensor is connected to the excitation module interface, and the signal acquisition coil of the snap-on sensor is connected to the electromagnetic signal acquisition module; Step 2: Configure the excitation module, select the required excitation frequency and download the program to provide a sine excitation of the corresponding frequency; Step 3: Configure the electromagnetic signal acquisition module and select an appropriate amplification factor; Step 4: Configure the data processing module and install a wireless communication module. The data processing module processes the collected data, calculates the equivalent series resistance value and the equivalent series reactance value, and uploads them to the data analysis device through the wireless communication module; Step 5: Configure the data analysis device, install a wireless communication module, select the required baud rate, and receive the equivalent series resistance value and the equivalent series reactance value transmitted by the data processing module; Step 6: By moving the snap-on sensor at a constant speed, the induced voltage signal of the signal acquisition coil and the excitation current signal of the excitation coil are collected in real time. The data analysis device displays the data in real time and displays the relationship curve between the data and the displacement; Step 7: Describe the damage condition of the stay cable by analyzing the measured equivalent series resistance value and equivalent series reactance value.

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