scholarly journals An Overall Deformation Monitoring Method of Structure Based on Tracking Deformation Contour

2019 ◽  
Vol 9 (21) ◽  
pp. 4532 ◽  
Author(s):  
Xi Chu ◽  
Zhixiang Zhou ◽  
Guojun Deng ◽  
Xin Duan ◽  
Xin Jiang
Keyword(s):  
Edge Detection ◽  
Orthogonal Projection ◽  
Perspective Transformation ◽  
Deformation Monitoring ◽  
Structural Deformation ◽  
Health State ◽  
Test Beam ◽  
Monitoring Method ◽  
Projection Image ◽  
Complete Deformation

In structural deformation monitoring, traditional methods are mainly based on the deformation data measured at several individual points. As a result, only the discrete deformation, not the overall one, can be obtained, which hinders the researcher from a better and all-round understanding on the structural behavior. At the same time, the surrounding area around the measuring structure is usually complicated, which notably escalates the difficulty in accessing the deformation data. In dealing with the said issues, a digital image-based method is proposed for the overall structural deformation monitoring, utilizing the image perspective transformation and edge detection. Due to the limitation on camera sites, the lens is usually not orthogonal to the measuring structure. As a result, the obtained image cannot be used to extract the deformation data directly. Thus, the perspective transformation algorithm is used to obtain the orthogonal projection image of the test beam under the condition of inclined photography, which enables the direct extraction of deformation data from the original image. Meanwhile, edge detection operators are used to detect the edge of structure’s orthogonal projection image, to further characterize the key feature of structural deformation. Using the operator, the complete deformation data of structural edge are obtained by locating and calibrating the edge pixels. Based on the above, a series of load tests has been carried out using a steel–concrete composite beam to validate the proposed method, with the implementation of traditional dial deformation gauges. It has been found that the extracted edge lines have an obvious sawtooth effect due to the illumination environment. The sawtooth effect makes the extracted edge lines slightly fluctuate around the actual contour of the structure. On this end, the fitting method is applied to minimize the fluctuation and obtain the linear approximation of the actual deflection curve. The deformation data obtained by the proposed method have been compared with the one measured by the dial meters, indicating that the measurement error of the proposed method is less than 5%. However, since the overall deformation data are continuously measured by the proposed method, it can better reflect the overall deformation of the structure, and moreover the structural health state, when compared with the traditional “point” measurements.

Ultrasonic Transceiver-Based Structural Deformation Monitoring with Location Ability

2014 ◽  
Vol 721 ◽  
pp. 442-445
Author(s):  
Wei Zheng ◽  
Chun Xian Wu ◽  
Rong Rong Cui
Keyword(s):  
Spatial Relations ◽  
Deformation Monitoring ◽  
Monitoring Data ◽  
Structural Deformation ◽  
Monitoring Method ◽  
Regional Monitoring ◽  
Space Deformation ◽  
Structural Surface

Regional coverage monitoring for structural deformation remains a challenge for current technologies. A coverage regional monitoring method based on dual ultrasonic transceivers and exhibiting deformation location ability is presented. The spatial projecting model of dual ultrasonic beams is established to determine the monitoring scope of the structural surface in space. Deformation location principles are induced by analyzing the spatial relations of the monitoring data of dual ultrasonic transceivers. Finally, an experiment is proposed to illustrate the method.

Application of FBG Sensor in Shaft Structural Deformation Monitoring of JINCHUAN Mine No.3

2011 ◽  
Vol 243-249 ◽  
pp. 5420-5426 ◽  
Author(s):  
Zeng Hui Liu ◽  
Qian Gao ◽  
Zhi Qiang Yang
Keyword(s):  
Monitoring System ◽  
Practical Experience ◽  
Structural Condition ◽  
Deformation Monitoring ◽  
Reinforced Concrete Beams ◽  
Structural Deformation ◽  
Mine Shaft ◽  
Monitoring Method ◽  
Shaft Deformation

In order to effectively evaluate the security status of shaft and to make timely and accurate forecasts before the shaft break disaster, lead into fiber brag grating technology in the mine shaft deformation monitoring. Designing laboratory experiments verified FBG sensing the reliability of deformation and strain transfer law in reinforced concrete beams, while provide practical experience to the FBG sensors installed on the actual shaft structure. According to the structural condition of the main shaft of JINCHUAN Mine No.3, designed 8 monitoring sections in different level ingate upper and lower and installed fiber optic grating sensors, forming a fully automatic real-time and long-term deformation monitoring system. Initial monitoring results indicate that only the No.4 (down) sensors was failure, but the other seven monitoring sections can effectively detect the corresponding strain, and the monitoring system was stable. The fiber optical sensing technology has broad application prospects in the state's long-term monitoring deformation of the mine project, for the mine shaft deformation monitoring provides a more reliable monitoring method.

Structural displacement and strain monitoring based on the edge detection operator

2016 ◽  
Vol 20 (2) ◽  
pp. 191-201 ◽  
Author(s):  
Wei Lu ◽  
Yan Cui ◽  
Jun Teng
Keyword(s):  
Edge Detection ◽  
Image Features ◽  
Image Feature ◽  
Monitoring Method ◽  
Strain Monitoring ◽  
Morphological Operator ◽  
Filtering Effect ◽  
Circular Target ◽  
Plane Displacement ◽  
The Cost

To decrease the cost of instrumentation for the strain and displacement monitoring method that uses sensors as well as considers the structural health monitoring challenges in sensor installation, it is necessary to develop a machine vision-based monitoring method. For this method, the most important step is the accurate extraction of the image feature. In this article, the edge detection operator based on multi-scale structure elements and the compound mathematical morphological operator is proposed to provide improved image feature extraction. The proposed method can not only achieve an improved filtering effect and anti-noise ability but can also detect the edge more accurately. Furthermore, the required image features (vertex of a square calibration board and centroid of a circular target) can be accurately extracted using the extracted image edge information. For validation, the monitoring tests for the structural local mean strain and in-plane displacement were designed accordingly. Through analysis of the error between the measured and calculated values of the structural strain and displacement, the feasibility and effectiveness of the proposed edge detection operator are verified.

Accuracy of Static Differential GPS Techniques; Implications for Structural Deformation Monitoring

2009 ◽  
Vol 62-64 ◽  
pp. 31-38
Author(s):  
J.O. Ehiorobo
Keyword(s):  
Carrier Phase ◽  
Reference Frames ◽  
Phase Measurement ◽  
Sampling Rate ◽  
Tall Buildings ◽  
Deformation Monitoring ◽  
Structural Deformation ◽  
Control Network ◽  
Differential Gps ◽  
Engineering Structures

In recent years, the need to monitor for Deformation in Engineering Structures such as Dams, Bridges and Tall buildings have become more necessary as a result of reported failures of many of these structures with catastrophic consequences globally. Global Positioning System (GPS) is highly automated and less labour intensive than other conventional techniques used in structural deformation monitoring. For most applications, such as National Geodetic Control Network, Urban Control Network and other Engineering Control Network, an accuracy in the cm level for most GPS work is quite adequate. For Structural deformation monitoring however, the required accuracy is in millimeters. In this paper, the use of Static Differential GPS method with multiple receivers for high precision measurement was investigated using the monitoring Stations at Ikpoba Dam as case study Scenerio. Four units of LEICA 300 Dual Frequency GPS receivers were deployed for code and carrier phase measurements with observation session of 1hr at a sampling rate of 15 sec. Baseline Processing and Least Squares Adjustment of observation was carried out in WGS 84 and NTM reference frames using the LEICA SKI-PRO Processing software and Move. Analysis of the results revealed that the number of outliers in the observation were <5% and the accuracy of horizontal and vertical coordinates were 4mm maximum for horizontal and 2mm maximum for vertical. The study revealed that in areas with favourable satellite constellation and appropriate reduction or elimination of multipath and other noise like errors, Static Differential GPS techniques with a combination of code and carrier phase measurement gives good results for structural deformation monitoring.

scholarly journals Structural Health Monitoring System Based on FBG Sensing Technique for Chinese Ancient Timber Buildings

Sensors ◽  
2019 ◽  
Vol 20 (1) ◽  
pp. 110 ◽  
Author(s):  
Shao-Fei Jiang ◽  
Ze-Hui Qiao ◽  
Ni-Lei Li ◽  
Jian-Bin Luo ◽  
Sheng Shen ◽  
...  
Keyword(s):  
Structural Health Monitoring ◽  
Monitoring System ◽  
Health Monitoring ◽  
Structural Deformation ◽  
Beam Deflection ◽  
Health State ◽  
Health Monitoring System ◽  
Structural Health ◽  
Structural Health Monitoring System

Due to the long-term service, Chinese ancient timber buildings show varying degrees of wear. Thus, structural health monitoring (SHM) for these cultural and historical treasures is desperately needed to evaluate the service status. Although there are some FBG sensing-based SHM systems, they are not suitable for Chinese ancient timber buildings due to the differences in architectural types, structural loads, materials, and environment. Besides, a technical gap in Fiber Bragg grating (FBG) sensing-based column inclination monitoring exists. To overcome these weaknesses, this paper develops an FBG sensing-based structural health monitoring system for Chinese ancient Chuan-dou-type timber buildings that aims at monitoring structural deformation, i.e., beam deflection and column inclination, temperature, humidity, and fire around the building. An in-situ test and simulation analyses were conducted to verify the effectiveness of the developed SHM system. To validate the long-term-operation of the developed SHM system, monitoring data within 15 months were analyzed. The results show good agreement between the developed SHM system in this paper and other methods. In addition, the SHM system operated well in the first year after its deployment. This implies that the developed SHM system is applicable and effective in the health state monitoring of Chinese ancient Chuan-dou-type timber buildings, laying a foundation for damage prognosis of such types of timber buildings.

scholarly journals Research on Monitoring Method of Remote Deformation and System Application Based on Image

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Yu Zhang ◽  
Ruofei Zhong ◽  
Yongrong Li ◽  
Haili Sun
Keyword(s):  
Monitoring System ◽  
High Precision ◽  
Engineering Application ◽  
Deformation Monitoring ◽  
Image Feature ◽  
Deformation Analysis ◽  
Monitoring Cost ◽  
Scale Invariant ◽  
Monitoring Method ◽  
Reference Target

The development of information technology and computer science has put forward higher requirements on the intelligence of deformation monitoring. We study a method based on image deformation analysis, which uses Scale-Invariant Feature Transform (SIFT) to extract image feature points after preprocessing the acquired images, applies All-Pixels Matching (APM) method to the sequence images to do further high-precision matching to achieve the accuracy of subpixels, and finally solves the deformation variables according to the relationship of the real size of the reference target and its pixel. Wavelet analysis and least squares are used to improve the image quality and matching accuracy. Based on this method, we design and develop a new remotely automated deformation monitoring system. In this paper, we introduce the algorithm principle of deformation analysis, the integration of the system, and the engineering application example of the monitoring system. The monitoring accuracy of the system satisfying 0.1 mm within 10 m and 0.8 mm within 60 m is verified in the simultaneous comparison observation according to the high-precision total station, which illustrates the effectiveness of the present deformation analysis method and monitoring system and also has the characteristics of low monitoring cost and high degree of automation.

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