CN-122017000-A - Integrated detection system for non-contact monitoring of corrosion state of reinforced concrete structure

CN122017000ACN 122017000 ACN122017000 ACN 122017000ACN-122017000-A

Abstract

The invention discloses an integrated detection system for non-contact monitoring of a corrosion state of a reinforced concrete structure, which comprises a plurality of embedded sensing carriers, a permanent magnet exciting body, a signal conditioning and processing unit, a wireless transmission unit and a data analysis terminal, wherein the embedded sensing carriers are fixed in grids of a reinforcement cage before concrete pouring, the sensing carriers are internally provided with cavities, the permanent magnet exciting body is fixedly arranged at the center of the cavities, the Hall sensor array is uniformly distributed along the inner wall of the cavities, the signal conditioning and processing unit is electrically connected with the Hall sensor array, the wireless transmission unit is used for transmitting digitized magnetic field data to the data analysis terminal, the data analysis terminal is used for receiving and storing the magnetic field data, a detection model is constructed based on an equivalent magnetic circuit model, the mass loss of a shell of the sensing carrier is calculated, and the corrosion state is estimated by using the mass loss. The method can accurately and stably evaluate the corrosion position and degree of the steel bars in the concrete, and is suitable for in-service durability evaluation, health monitoring and maintenance decision support of buildings and infrastructure.

Inventors

LIN XUMEI
SHEN JIAHUI
TIAN YANBING
QIN ZHEN
ZHU WENJIE
Ni Chi
Yan Shankun
WANG PENGGANG

Assignees

青岛理工大学

Dates

Publication Date: 20260512
Application Date: 20260205

Claims (9)

1. An integrated detection system for non-contact monitoring of corrosion status of reinforced concrete structures, comprising: The sensor comprises a plurality of optimized embedded sensing carriers, a plurality of sensor modules, a sensor module and a sensor module, wherein the optimized embedded sensing carriers are fixed in grids of a reinforcement cage before concrete pouring so as to be embedded in a concrete structure body, and a cavity is formed in the sensing carriers; The permanent magnet exciting body which is subjected to parametric modeling and iterative optimization is fixedly arranged at the central position of the cavity and is used for constructing a stable magnetic flux density exciting field in a region to be detected, key parameters of the magnetizing direction, the central position offset and the air gap thickness of the permanent magnet exciting body are set as variable values, a parametric model is constructed in a Comsol Multiphysics environment, wherein the exciting field is quantitatively characterized in a distance range, a central projection point of the permanent magnet exciting body is taken as an origin, and the radial distance is measured on the surface to be detected In step size Sampling to obtain magnetic flux density distribution And by For intensity constraint, minimizing the peak-to-valley difference of B (r) in the distance domain, i.e. minimizing By introducing a self-adaptive step gradient descent method of magnetic circuit constraint, automatically adjusting parameters and solving magnetic field distribution for multiple times under the boundary conditions of permanent magnet exciting body volume constraint and installation space constraint in a reinforced concrete structure, and finally obtaining an optimal parameter combination meeting design requirements; The method comprises the steps of adopting a Hall sensor array uniformly distributed along the inner wall of a cavity for collecting magnetic flux density response signals caused by the corrosion state change of a measured steel bar, wherein a plurality of Hall sensors in the Hall sensor array are arranged at the central positions of six inner wall surfaces and eight inner angle positions of the cavity so as to form three-dimensional space multipoint magnetic field measurement; the data analysis terminal is used for receiving and storing magnetic field data, constructing a detection model based on an equivalent magnetic circuit model, enabling a magnetic field passage to be equivalent to an inner branch and an outer branch which are connected in parallel by the equivalent magnetic circuit model, calculating the mass loss of the sensor carrier shell according to the detection model, and evaluating the corrosion state by utilizing the mass loss; Magnetic induction intensity at uniform corrosion Loss of quality of steel bar Detection model in between: ; magnetic induction intensity at non-uniform corrosion Loss of quality of steel bar The detection model between is ; Wherein, the And Respectively equivalent magnetomotive force and equivalent magnetic resistance of the permanent magnet exciting body, Is the effective air gap area of the cavity, And The permeability of the inner branch is respectively equal to that of the inner branch in the uniform corrosion and the non-uniform corrosion, And The thickness of the rust layer in the uniform corrosion and the non-uniform corrosion respectively, Is the magnetic permeability of the outer branch.
2. An integrated detection system for non-contact monitoring of the corrosive status of a reinforced concrete structure according to claim 1, wherein a plurality of pre-embedded sensing carriers are correspondingly arranged in the corrosion-prone or critical stress section of the reinforcement cage.
3. The integrated detection system for non-contact monitoring of corrosion state of reinforced concrete structure according to claim 1, wherein the volume constraint of the permanent magnet exciter is that the length, width and height of the permanent magnet exciter must be respectively smaller than the inner dimension of the corresponding direction of the cavity, and the installation space constraint is determined according to the grid dimension of the reinforcement cage in the target reinforced concrete structure and the design thickness of the concrete protection layer, so as to limit the effective dimension of the cavity, the installable position and offset range of the permanent magnet exciter in the cavity and the allowable upper and lower limits of the air gap thickness.
4. The integrated detection system for non-contact monitoring of corrosion status of reinforced concrete structure according to claim 1, further comprising a signal conditioning and processing unit electrically connected to the hall sensor array for filtering, amplifying and analog-to-digital converting the collected magnetic field signal to obtain digitized magnetic field data; the signal conditioning and processing unit comprises a low-noise amplifying and filtering circuit and a data acquisition circuit taking STM32F303RE as a core, and the on-chip high-speed high-precision ADC is utilized to carry out high-efficiency and low-noise acquisition and processing on the magnetic field signals of the Hall sensor.
5. The integrated detection system for non-contact monitoring of corrosion state of reinforced concrete structure according to claim 1, wherein a data transmission line is arranged between the hall sensor and the signal conditioning and processing unit, and the data transmission line is a shielded twisted pair or coaxial cable and is led out through a waterproof joint and a sealed conduit, so as to reduce electromagnetic interference and adapt to construction environment.
6. The integrated detection system for non-contact monitoring of corrosion state of reinforced concrete structure according to claim 1, further comprising a wireless transmission unit for transmitting digitized magnetic field data to a data analysis terminal, wherein the wireless transmission unit is cellular communication, wi-Fi or Bluetooth, and supports local storage and cloud synchronization.
7. The integrated detection system for non-contact monitoring of corrosion state of reinforced concrete structure according to claim 1, wherein a replaceable anti-wear insulating layer is arranged on one side of the hall sensor, which is in contact with the inner wall surface of the cavity, so as to ensure measurement stability and electrical insulation safety.
8. The integrated detection system for non-contact monitoring of the corrosion state of a reinforced concrete structure according to claim 1, wherein the judging conditions of uniform corrosion and non-uniform corrosion are that the multi-point data of the Hall sensor array are analyzed, if the standard deviation of the change rate of each point data relative to an initial value is smaller than a preset threshold value, the uniform corrosion is judged, and a uniform corrosion detection model is selected for calculation; If the standard deviation of the change rate is larger than a preset threshold, judging that the corrosion is non-uniform, and selecting a non-uniform corrosion detection model for calculation.
9. The integrated detection system for non-contact monitoring of the corrosion state of a reinforced concrete structure according to claim 1, wherein the equivalent magnetic circuit model is characterized in that a magnetic field passage is equivalent to an inner branch and an outer branch which are connected in parallel, wherein the inner branch is a path formed by magnetic flux passing through an air gap in a shell, the inner wall of the shell and an unetched shell wall and then returning to a permanent magnet exciter, and the outer branch is a path formed by magnetic flux sequentially passing through the inner wall of the shell, the unetched shell wall, a rust layer on the outer surface of the shell and concrete and an air medium and then returning to the permanent magnet exciter.

Description

Integrated detection system for non-contact monitoring of corrosion state of reinforced concrete structure Technical Field The invention belongs to the technical field of health monitoring and nondestructive testing of civil engineering structures, and particularly relates to an integrated detection system for non-contact monitoring of corrosion states of reinforced concrete structures. Background In the field of construction engineering today, reinforced concrete applications are very common, but the corrosion problems accompanying them are increasingly prominent, and cause significant economic and safety hazards. Research shows that the corrosion of the steel bar is a dominant factor causing the durability degradation of the concrete structure, and the expansion effect generated by the corrosion is used for inducing the cracking of the protective layer, so that the penetration of corrosive media such as chloride ions, oxygen, moisture and the like is accelerated, the vicious circle of corrosion-cracking is formed, and the bearing performance of the structure is obviously weakened. Therefore, the corrosion degree of the steel bars in the concrete can be accurately obtained, the durability state can be evaluated, and the method has important significance in structural safety analysis, life prediction and maintenance decision. The existing steel bar corrosion detection technology is generally divided into two categories of damage detection and nondestructive detection. The damage detection usually needs to strip the protective layer or take out the reinforcing steel bar, and although the corrosion rate can be directly and accurately measured, the structural integrity can be damaged, and the method is not suitable for long-term monitoring and in-service evaluation. The nondestructive testing method is widely applied to engineering, and mainly comprises an electrochemical method and a physical method, wherein the electrochemical method can quantitatively evaluate corrosion states, is suitable for early warning, is usually in electrical contact with reinforcing steel bars and is greatly influenced by environment and unfavorable for large-area rapid detection, and the physical method has the advantages of non-contact, nondestructive testing, suitability for large-area rapid evaluation and the like, and is more suitable for the field requirements of the engineering, wherein electromagnetic detection realizes damage identification by utilizing electromagnetic characteristic changes caused by reinforcing steel bar corrosion, and still has room for improvement in the aspects of anti-interference performance, decoupling identification capability, coverage range and engineering feasibility. Around the links of reinforced concrete structure damage assessment, reinforced steel rust electromagnetic signal acquisition, sensor calibration, signal transmission and the like, different solutions have been proposed by related patents. For example, CN114528753a discloses an intelligent monitoring device and method for evaluating the damage degree of reinforced concrete, focuses on comprehensive evaluation of the damage degree by collecting structure related information, CN109541016a discloses a portable device for collecting rusted reinforced electromagnetic sensor signals and a using method, mainly focuses on portable collection of rusted reinforced electromagnetic signals, CN113720755A discloses a reinforced multi-point rusting calibration device and calibration method suitable for built-in magnetic sensors, improves calibration and correction problems in magnetic sensor detection, and CN115388946a discloses a device and method for evaluating wireless transmission efficiency of electromagnetic signals of built-in sensors of concrete, and focuses on wireless transmission efficiency evaluation and reliability problems of electromagnetic signals of built-in sensors of concrete media. However, in the prior art, researches are respectively carried out from different links of a monitoring link, or the method is biased to stage detection and inspection type signal acquisition, or depends on pre-calibration and manual participation, or only evaluates single problems such as signal transmission, and the like, and a long-term, stable and practical in-situ monitoring system facing the service period is difficult to form under the actual condition of engineering, and meanwhile, the influence of factors such as position deviation, complex corrosion morphology, environmental interference and the like possibly existing in a concrete structure on the accuracy of an electromagnetic detection result still lacks effective inhibition and quantitative characterization means, so that the aspects of anti-interference performance, decoupling identification capability and engineering feasibility still have room for further improvement. Based on the above-mentioned current situation, it is necessary to provide an electromagnetic detection scheme which