Tiny lateral displacement detection methods of image correlation matching

2013 ◽  
Author(s):  
Xing-bo Wang
Author(s):  
Shudan Wang ◽  
Mingzhi Guan ◽  
Jiaxiang Chen ◽  
Xingzhe Wang ◽  
You-He Zhou

Abstract A fast and effective quench detection method is especially challenging in the development of high-field high-temperature superconducting (HTS) magnets for their safe operations and reliably releasing the stored energy during a quench. The occurrence and propagation of a quench are often accompanied by strong thermal and magneto-mechanical responses within superconducting magnets. Aiming to detect a quench in the whole process and capture the thermoelastic behavior associated with it, a new detection technique with a visual and full-field perception based on the digital image correlation (DIC) method is proposed in the present study. The experiment of a quench triggered thermally by a local spot heater is conducted for a YBCO coated conductor tape in a cryogenic chamber. The evolution and characteristics of the full-field strain in the HTS tape during the processes of a non-quench, a quench occurrence and quench propagation are intuitively presented with experimental observations. For the comparison purpose, the conventional quench detection methods by monitoring temperature and voltage signals during a quench are also utilized experimentally. The results verify the visual and full-field quench detection method which uses a criterion of thermoelastic strain-rate for the quench occurrence and the evolution of strain contours for the normal zone propagating aspect. Additionally, a numerical quench model of coupled thermoelasticity to simulate the experiment is established and solved with the aid of Comsol multiphysics software. The quantitative results are in good agreement with the experimental measurements to prove the reliability and availability of the developed detection method. Since the DIC method is non-contact and insensitivity to intense electromagnetic interferences, it is expected to provide a new technique on quench issues and some basic measurements on strain/stress behaviors in extreme environments of high-field HTS magnets in the future.


2017 ◽  
Vol 44 (8) ◽  
pp. 0804003 ◽  
Author(s):  
Shan Baohua ◽  
哈尔滨工业大学土木工程学院 ◽  
黑龙江 哈尔滨 ◽  
哈尔滨工业大学结构工程灾变与控制教育部重点实验室 ◽  
黑龙江 哈尔滨 ◽  
...  

2021 ◽  
Vol 283 ◽  
pp. 01022
Author(s):  
Yongcheng Liu ◽  
Yonglai Zheng ◽  
Yujue Zhou

As one of the most common structural forms in port engineering, the operation environment of high-pile wharf is quite harsh and complex, and its pile foundation often produces structural damage of different degrees. Until now, there is a lack of efficient, safe and economic damage detection methods. A novel and precise real-time structural damage detection (SDD) method using both finite element modelling (FEM) and 1D convolutional neural networks (CNNs) is established in this study. The results indicate that the proposed method could accurately identify the presence and location of damage in real time. The results also demonstrated that the proposed 1D CNNs based model are more sensitive to the longitudinal and lateral displacement responses of the high-pile wharf structure.


Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 489
Author(s):  
Chao-Ching Ho ◽  
Guan-Hong Li

In this study, laser processing equipment was used to drill aluminum alloy materials and with different auxiliary mechanisms, the deformation around the holes after processing was observed. The experimental results show that, due to the high temperature generated during laser processing, a large thermal gradient causes thermal stress to be introduced into the test piece and outward expansion deformation occurs. In this study, the digital image correlation and residual stress detection methods were applied. Based on the correlation between the drilled hole depth and the hole deformation, the hole depth of the laser processing was estimated. The average coefficient of determination for all auxiliary mechanisms is 0.82. The experimental results confirm that the digital image correlation method can be used to estimate the hole depth of laser processing.


2013 ◽  
Vol 8 (8) ◽  
pp. 375-382
Author(s):  
Jincai Chang ◽  
Shujing Zhao ◽  
Aimin Yang ◽  
Liyu Chen ◽  
Xiaoli Meng

2021 ◽  
Author(s):  
Maxime Henriquet ◽  
Adrien Moulin ◽  
Matija Vukovski ◽  
Branko Kordić ◽  
Marko Budić ◽  
...  

<p>The Petrinja-Pokupsko fault-system is a NW-SE right-lateral fault system that ruptured during the 29 December 2020 Mw 6.4 earthquake (~40km south-east of Zagreb, Croatia). Field analysis revealed opening of cracks and offsets of several centimeters (3 to 40 cm) along a ~20 km long fault zone extending from the Kupa river (in the northwest) to the Petrinjčica river (in the southeast). Optical image correlation based on WorldView satellite images has been used to document the first-order near-field rupture signal. The pre-event image was acquired on 7th December 2017, and the post-event image on 15th January 2021. The first results indicate a right-lateral displacement of ≈75 cm with a small (<10 cm) extensional dip-slip component localized on the Petrinja fault. Using 1:5,000 topographic maps, a WorldView-derived DEM (1 m), and field observations, we identified and quantified cumulative dextral offsets along the central and southern section of the fault (south of Župić). Right-lateral offsets range from 5 to 200 m near Križ and Cepeliš (central sector). Diverted streams also extend southeast of the Petrinjčica river, where no surface ruptures have currently been reported to date. To the northwest, perched valleys, wind gaps, and karst features all testify to ongoing uplift across NW-SE-trending anticlines. It is unclear if the primary component of faulting changes from strike-slip (in the SE) to reverse (in the NW), or if these folds merely record a transpressive component across the fault. The activity of this fault system is poorly known. The region experienced a magnitude Mw 5.8 in 1909, ~30 km northwest of Petrinja, which may have been associated with the Petrinja-Pokupsko fault system. The recent 29 December 2020 earthquake confirms the seismic potential of this fault system to generate Mw>6 earthquakes. Since the fault extends farther NW and SE, from the Vukomeričke Gorice hills to Mount Kozara (Bosnia), for a total length of about 100 km, it could generate potentially larger events. It is also noteworthy that the 2020 Petrinja event occurred only 9 months after the Zagreb March 2020 (Mw 5.3) earthquake. This event occurred on an ENE-WSW-trending thrust fault, broadly orthogonal to the right-lateral Petrinja-Pokupsko fault system, ~45 km north of Petrinja, and raises the prospect of potential interplay between strike-slip and thrust faults in moderate strain-rate intra-plate settings. To address this problem, future works will aim at constraining the geometry of this fault network and its seismogenic potential.</p>


2013 ◽  
Vol 838-841 ◽  
pp. 1054-1057
Author(s):  
Han Zhang Wang ◽  
Shen Zhou Tan ◽  
An Quan Peng ◽  
Bao Kun Hong

Bridge static load test is a conventional method to ensure the safety of bridge, but time-consuming and inconvenient in certain situation to implement. This paper attempts to use photogrammetry method to achieve deformation measurements in the bridge static load test, which is based on time baseline method. using image correlation matching for distance measurement, and using the edge recognition of the targets and ellipse fitting to get the conversion factor of in-image and actual distance. The validation of laboratory experiment and engineering application proved its strong practical value with high accuracy.


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