Spatial and Wavelength Multiplexing Architectures for Extreme Strain Monitoring System Using Identical-Chirped-Grating-Interrogation Technique

1997 ◽  
Author(s):  
L. Zhang ◽  
R W Fallon ◽  
A. Gloag ◽  
I Bennion ◽  
F. M. Haran ◽  
...  
Keyword(s):  
Monitoring System ◽  
Wavelength Multiplexing ◽  
Strain Monitoring ◽  
Chirped Grating ◽  
Interrogation Technique

scholarly journals Strain monitoring system for steel and concrete structures

2018 ◽  
Vol 10 ◽  
pp. 25-32 ◽  
Author(s):  
E. Cheilakou ◽  
N. Tsopelas ◽  
A. Anastasopoulos ◽  
D. Kourousis ◽  
D. Rychkov ◽  
...  
Keyword(s):  
Monitoring System ◽  
Concrete Structures ◽  
Strain Monitoring

Integrated geophysical and geotechnical monitoring for multiscale rock mass damaging investigation at the Acuto Field-Lab (Italy)

2021 ◽  
Author(s):  
Guglielmo Grechi ◽  
Danilo D'Angiò ◽  
Matteo Fiorucci ◽  
Roberto Iannucci ◽  
Luca Lenti ◽  
...  
Keyword(s):  
Rock Mass ◽  
Monitoring System ◽  
Thermal Stresses ◽  
Central Italy ◽  
Jointed Rock ◽  
Failure Behavior ◽  
Rock Masses ◽  
Geotechnical Monitoring ◽  
Strain Monitoring

<p>Rock mass damaging has become a topic of great interest in the engineering-geology research community during the last decades as it can significantly influence slopes stability. In this sense, the study of mechanics and dynamics of jointed rock masses represents a challenge because it will allow to better understand how external continuous and transient stressors can influence the short- to long-term stability controlling their pre-failure behavior. Consequently, the detection of permanent changes in physical and mechanical parameters, due to periodic or transient stressors, is an important target to mitigate the related geological risk as it can potentially lead rock masses to failure, especially when infrastructures and natural or cultural heritages are exposed elements. In this framework, the Acuto field laboratory (Central Italy) has been designed and implemented in 2016 within an abandoned quarry by employing an integrated geotechnical and geophysical monitoring system, with the aim of investigating how natural and anthropic conditioning factors could lead fractured rock masses to failure. The integrated monitoring system, which is installed on a potentially unstable 20-m<sup>3</sup> jointed rock block, is composed of several strain devices (i.e., strain gauges -SG- and jointmeters -JM-), one fully equipped weather station, one rock thermometer, eight high-sensitivity microseismic uniaxial accelerometers and optical and InfraRed Thermal cameras. The acquisition of long-term monitoring time-series, coupling multimethodological approaches, allowed to establish cause-to-effect relationships among different environmental stressors and induced strain effects, highlighting the continuous action of thermal stresses on rock mass deformations both at the daily and seasonal timescales. In fact, while the analysis of thermal and strain monitoring data allowed to characterize the cyclic contraction and relaxation response of major rock fractures and microcracks to temperature fluctuations, the microseismic monitoring array was able to detect during thermal transient (i.e., freezing conditions) the occurrence of microseismic emissions potentially related to the genesis or progressive growth of pre-existing cracks.</p><p>Starting from 2018, experimental activities at the Acuto field lab are supported by the “Dipartimento di Eccellenza” project of the Italian Ministry of Education Universities and Research funds attributed to the Department of Earth Sciences of the University of Rome “Sapienza”.  In this framework, the Acuto filed laboratory will undergo a structural upgrade that will be aimed at the investigation of two new sectors of the abandoned quarry. These new sectors will be instrumented with innovative thermal profiles probe, fiber Brag grating sensors and traditional SG and JM for detailed stress-strain monitoring, acoustic emission sensors and high-frequency and low-frequency geophones for ambient seismic noise monitoring and microseismic events detection as well as accelerometers for evaluating the rock mass response in the case of seismic shaking. The main goal of such an improvement will be both technical and methodological, and will shed light on the application of integrated geophysical and geotechnical monitoring approaches in investigating the multiscale rock mass damaging process as well as the detection of rock mass failure precursors by using non-conventional combinations and configurations of geotechnical and broad-band geophysical devices.</p>

scholarly journals Wearable respiratory strain monitoring system based on textile-based capacitive strain sensor

2020 ◽  
Vol 1570 ◽  
pp. 012033
Author(s):  
ZHONG Jun ◽  
LI Chun-na ◽  
ZHU Wen-liang ◽  
ZHOU Hong ◽  
LIU Yong-feng ◽  
...  
Keyword(s):  
Monitoring System ◽  
Strain Sensor ◽  
Strain Monitoring ◽  
Capacitive Strain

Fibre Bragg grating interrogation technique based on a chirped grating written in an erbium-doped fibre

2003 ◽  
Vol 14 (11) ◽  
pp. 1993-1997 ◽  
Author(s):  
R Romero ◽  
O Frazão ◽  
P V S Marques ◽  
H M Salgado ◽  
J L Santos
Keyword(s):  
Bragg Grating ◽  
Fibre Bragg Grating ◽  
Erbium Doped ◽  
Chirped Grating ◽  
Interrogation Technique

Identical broadband chirped grating interrogation technique for temperature and strain sensing

1997 ◽  
Vol 33 (8) ◽  
pp. 705 ◽  
Author(s):  
R.W. Fallon ◽  
L. Zhang ◽  
A. Gloag ◽  
I. Bennion
Keyword(s):  
Strain Sensing ◽  
Chirped Grating ◽  
Interrogation Technique

Establishment and Application of the Pipeline Monitoring System in Permafrost Regions in China

2020 ◽  
Author(s):  
Jianping Liu ◽  
Pengchao Chen ◽  
Hong Zhang ◽  
Baodong Wang ◽  
Xiaoben Liu
Keyword(s):  
Temperature Field ◽  
Soil Temperature ◽  
Monitoring System ◽  
Field Monitoring ◽  
Measurement Unit ◽  
Displacement Monitoring ◽  
Ground Displacement ◽  
Oil Pipeline ◽  
Strain Monitoring ◽  
Permafrost Regions

Abstract Buried pipelines in permafrost regions are inevitably subjected to some typical geohazards, such as frost heave, thaw settlement and thaw slumping. The bending or/and longitudinal strains will be induced in pipe under these types ground movement, which is the potential cause of weld joint rupture. Thus, in order to prevent pipe failure, a comprehensive monitoring system was designed and used in the Mohe-Daqing oil pipeline in the permafrost region in northeast China. The Mohe-Daqing oil pipeline is built for importing oil from Russia and its north part of 440km lays in permafrost. The monitoring system includes soil temperature field monitoring system, ground displacement monitoring system and pipe strain monitoring system. The soil temperature field monitoring system, which uses fiber brag grating sensors, can monitor the distribution of surrounding soil temperature in radial direction of pipe in order to detect the change of active ring of permafrost. The ground displacement monitoring system, which is based on a total station, can discover any subsidence or heave of the pipe itself and the embankment along the pipeline. The pipe strain monitoring system, which includes pipe stress monitoring system based on fiber brag grating sensors and inertial measurement unit (IMU) mapping, can inspect the real-time change of pipe stress and the bending strain periodically respectively. Using the comprehensive monitoring system, the important parameters that affect pipeline integrity such as pipeline temperature, stress, strain and displacement of Mohe-Daqing oil pipeline can be supervised timely and effectively. And the accuracy and reliability of the monitoring system have been verified in practical application. In this paper, detail about how these systems are designed and installed on the Mohe-Daqing oil pipeline is elucidated and the monitoring data is analyzed. Through these data, the present mechanical situation of Mohe-Daqing oil pipeline is safe, but the long-term change is critical because of the soaring oil temperature that is far high than the design temperature. The monitoring system is of great significance to ensure the safe operation of Mohe-Daqing pipeline and can provide reference for the pipeline operation in permafrost areas.

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