CN-122015682-A - Distributed crack monitoring network and application thereof

Abstract

The invention discloses a distributed crack monitoring network and application thereof, wherein a glass fiber geogrid which has good synergy with concrete and can transfer strain to the greatest extent is used as a flexible matrix, and a plurality of fiber bragg grating sensors with gauge length of 100mm determined by experimental optimization are distributed and consolidated on the flexible matrix, so that an integrated sensing network is formed. The monitoring network can be directly adhered to the surface of a concrete test piece, and strain is perceived through a sensing network so as to monitor crack initiation and expansion in real time. According to the invention, the glass fiber geogrid is selected and combined with the optimal sensor gauge length of 100mm, so that the high-efficiency transmission of strain is ensured, the sensitivity and the precision of monitoring microcracks are obviously improved, and the distributed long-term monitoring of a large-range area is realized. The design is simple and convenient to manufacture, low in cost and flexible in layout, and provides an economic, efficient and reliable solution for structural health monitoring.

Inventors

• WANG JIARUI
• ZHAO XING
• WU JIN
• ZHANG LIFANG

Assignees

• 南京航空航天大学

Dates

Publication Date

20260512

Application Date

20260205

Claims (5)

1. 1. The distributed crack monitoring network is characterized by comprising a flexible matrix, wherein the flexible matrix is of a geogrid structure; the fiber bragg grating FBG sensors are fixed on the geogrid, and the lengths of the gratings of the fiber bragg grating FBG sensors are equal in length.
2. 2. The distributed fracture monitoring network of claim 1, wherein the gauge length ranges from 30mm to 150 mm.
3. 3. The distributed fracture monitoring network of claim 1, wherein two ends of the fiber bragg grating sensor are fixedly connected with the geogrid, and the middle part of the fiber bragg grating sensor is suspended and in a tensed state.
4. 4. A distributed fracture monitoring network according to claim 2 or 3, wherein the gauge length is 100mm.
5. 5. The application of the distributed crack monitoring network according to any one of claims 1 to 4, wherein the distributed crack monitoring network is integrally adhered to a clean surface of a test piece to be tested, strain changes of the test piece to be tested are monitored through the fiber bragg grating sensor, and a detection result of whether cracks exist on the surface of the test piece to be tested is obtained.

Description

Distributed crack monitoring network and application thereof Technical Field The invention belongs to the technical field of engineering structures, and relates to a novel FBG-geogrid combined crack monitoring network with optimized gauge length. Background Under the combined action of long-term high-frequency and high-strength airplane load and environmental factors, the airport pavement is easy to crack, and the operation safety and the structural durability are directly affected. Currently, the crack monitoring of the cement concrete pavement mainly depends on manual inspection or a traditional point type sensor, the efficiency of the former is low and is limited by an operation time window, and the later is difficult to realize distributed and real-time monitoring of a large-range area. While the sensing technology represented by the Fiber Bragg Grating (FBG) has the advantages of electromagnetic interference resistance, long-distance distributed measurement realization and the like, the sensing technology still faces the problems of low sensor arrangement efficiency, insufficient deformation capacity in cooperation with the road surface, difficult long-term stability guarantee and the like when being applied to the road surface, and has high monitoring cost and limited precision. Therefore, a distributed crack monitoring technology which can be efficiently distributed, is coordinated with the deformation of the pavement and has good monitoring performance and economy is developed, and has important significance for realizing the real-time perception and intelligent operation and maintenance of the structural state of the airport pavement. Disclosure of Invention In order to solve the problem of difficulty in monitoring cracks of an airport pavement, the invention provides an FBG-geogrid composite crack monitoring network with optimized gauge length, so as to realize efficient monitoring of the cracks of the airport pavement. The technical scheme adopted by the invention is that the distributed crack monitoring network comprises a flexible matrix, wherein the flexible matrix is of a geogrid structure; the fiber bragg grating FBG sensors are fixed on the geogrid, and the lengths of the gratings of the fiber bragg grating FBG sensors are equal in length. Further, the scale distance is in the range of 30mm to 150 mm. Furthermore, the two ends of the fiber bragg grating sensor are fixedly connected with the geogrid, and the middle part of the fiber bragg grating sensor is suspended and in a tightening state. Further, the distributed crack monitoring network is integrally stuck to the clean surface of the test piece to be tested, and the strain change of the test piece to be tested is monitored through the fiber bragg grating sensor, so that a detection result of whether cracks exist on the surface of the test piece to be tested is obtained. As a preferred embodiment of the application, the gauge length is 100mm. Compared with the prior art, the invention has the advantages that: 1. Compared with the traditional point type sensor, the invention pre-integrates a plurality of sensors on one geogrid to form a sensing network which is 'just-in-place and just-in-use', thereby greatly simplifying the field installation procedure, reducing the sensing cost and time cost of unit area and being applicable to monitoring scenes with large-scale and densely distributed points. 2. The core innovation of the invention is that the optimal gauge length of the FBG sensor for monitoring concrete cracks is determined to be 100mm through experiments. The gauge length can capture the initiation of micro cracks in an early stage, can effectively track the subsequent expansion of the cracks, and avoids the problems of insufficient measuring range or reduced sensitivity of the conventional short gauge sensor, thereby obtaining more accurate and reliable quantitative monitoring data. 3. The whole crack monitoring network has good corrosion resistance and ageing resistance, and the FBG sensor is anti-electromagnetic interference. The full-coverage fixation of the epoxy resin effectively protects the sensor and the interface, so that the monitoring system can stably work for a long time in severe engineering environments such as humidity, salt fog and the like, and the defects that the traditional electrical sensor is easily affected by the environment and has poor long-term stability are overcome. 4. The monitoring net is flexible, light and thin sheet structure, can be directly adhered to the surface of a test piece, does not need drilling or embedding, belongs to nondestructive installation, is particularly suitable for health monitoring and evaluation of the existing structure, and has wide application range. Drawings In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for the description of the embodiments will be briefly described below, and it is appar