Crack monitoring capability of plastic optical fibers for concrete structures

Zhao, Jinlei; Bao, Tengfei; Chen, Rui

doi:10.1016/j.yofte.2015.05.008

Cited by 20 publications

(4 citation statements)

References 24 publications

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“…Besides the traditional methods, recent civil engineering practitioners rely on inspection devices with remote sensing methods to obtain construction health information. For example, cracks can be found by assessing the features of the ultrasonic signals [ 1 ], and optical fibers have been used in monitoring cracks [ 2 ]. These sensing techniques can feasibly achieve real-time performance, but they always require extensive devices and supporting facilities to perform the inspection task.…”

Section: Introductionmentioning

confidence: 99%

A Novel Real-Time Autonomous Crack Inspection System Based on Unmanned Aerial Vehicles

Tse

Sun

et al. 2023

Sensors

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Traditional methods on crack inspection for large infrastructures require a number of structural health inspection devices and instruments. They usually use the signal changes caused by physical deformations from cracks to detect the cracks, which is time-consuming and cost-ineffective. In this work, we propose a novel real-time crack inspection system based on unmanned aerial vehicles for real-world applications. The proposed system successfully detects and classifies various types of cracks. It can accurately find the crack positions in the world coordinate system. Our detector is based on an improved YOLOv4 with an attention module, which produces 90.02% mean average precision (mAP) and outperforms the YOLOv4-original by 5.23% in terms of mAP. The proposed system is low-cost and lightweight. Moreover, it is not restricted by navigation trajectories. The experimental results demonstrate the robustness and effectiveness of our system in real-world crack inspection tasks.

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Section: Introductionmentioning

confidence: 99%

A Novel Real-Time Autonomous Crack Inspection System Based on Unmanned Aerial Vehicles

Tse

Sun

et al. 2023

Sensors

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“…After cracking, two local micro-bending are formed on the fiber, and the backscatter signal transmitted through the fiber will cause loss. The crack position is judged according to the position of loss points generated on the fiber, and the crack width is identified according to the relationship between loss and crack width as well as the included angle between crack and fiber [14][15][16]. But it is difficult to bond fiber on the surface of underwater concrete structure, and the survival rate of fiber embedded in concrete is difficult to be guaranteed.…”

Section: Introductionmentioning

confidence: 99%

Crack width identification for underwater concrete structures using temperature tracer method

Zhang

Chen

Luo

et al. 2021

Meas. Sci. Technol.

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Based on the particularity of underwater concrete structure, a temperature tracer method based on heat transfer theory for crack detection was proposed. The basic way to identify cracks is to change the thermodynamic boundary conditions around cracks after cracking, which will lead to the change of cooling rate of the heat source near cracks. Based on this idea, a set of crack monitoring system composed of a temperature sensing system, a heating system, a monitoring tube and multiple casing tubes was designed. By using this system, a series of crack monitoring tests were carried out on two kinds of concrete specimens. The results show that the monitoring scheme with casing tube can detect the crack position in still water, and this monitoring scheme can detect both crack position and width in flowing water. The sensitivity of it is higher than that of the monitoring scheme without casing tube.

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“…They can be broadly divided into nonoptical (electrical) and optical sensors. Examples of nonoptical sensors are acoustic emission sensors, capacitive sensors, ultrasonic sensors, strain gauges, carbon nanotubes, temperature sensors, and Linear Variable Differential Transformer (LVDT) sensors, whereas optical sensors include fiber Bragg gratings, optical fibers, image analysis methods, hyper‐spectral image processing, and digital image correlation . Over the past decade, we have developed optical‐mechanical sensors based on the moiré effect that can be applied for real‐time crack monitoring in concrete structures .…”

Section: Introductionmentioning

confidence: 99%

Novel moiré‐based crack monitoring system with smartphone interface and cloud processing

Ratnam

Ooi

Yen

2019

Struct Control Health Monit

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Summary A popular optical‐mechanical method used to monitor crack growth in concrete structures is based on the moiré effect. The moiré patterns are usually interpreted manually using a read‐out chart or by off‐line processing using custom‐made application software installed in a personal computer. Such methods are not convenient for on‐site crack inspection and measurement. In this work, cloud‐based application software has been developed that can be used to process moiré pattern images sent via a standard smartphone. The moiré pattern resulting from the overlapping of two circular gratings mounted across a crack is captured using the smartphone camera, cropped, and sent via Wi‐Fi or mobile data to cloud server. The cloud server software receives the moiré pattern image and processes it using an image processing algorithm to return the displacement magnitude and direction to the mobile device within a few seconds. The communication between the mobile software and cloud software is via Representational State Transfer protocol that allows further development to accommodate other client platforms. The accuracy of the algorithm has been tested by comparing the displacement data returned by the cloud server using controlled experiment. In the experiment, the gratings were subjected to in‐plane displacement along two orthogonal axes using 0.001‐mm resolution digital micrometers. The results show that the displacement magnitude and displacement direction can be determined within an accuracy of ±0.05 mm and ±5°, respectively. The smartphone interface with cloud processing of moiré patterns is shown to be a promising tool for on‐site crack inspection and monitoring.

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Crack monitoring capability of plastic optical fibers for concrete structures

Cited by 20 publications

References 24 publications

A Novel Real-Time Autonomous Crack Inspection System Based on Unmanned Aerial Vehicles

A Novel Real-Time Autonomous Crack Inspection System Based on Unmanned Aerial Vehicles

Crack width identification for underwater concrete structures using temperature tracer method

Novel moiré‐based crack monitoring system with smartphone interface and cloud processing

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