scholarly journals A Fiber Bragg Grating Borehole Deformation Sensor for Stress Measurement in Coal Mine Rock

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3267 ◽  
Author(s):  
Wusheng Zhao ◽  
Kun Zhong ◽  
Weizhong Chen
Keyword(s):  
Optical Fiber ◽  
Coal Mine ◽  
Stress Measurement ◽  
Mechanical Load ◽  
Field Tests ◽  
Test Accuracy ◽  
Stress Monitoring ◽  
Stress Changes ◽  
Term Performance

A borehole deformation sensor for long-term stress monitoring in coal mine rock based on optical fiber Bragg gratings (FBGs) is presented. The sensor converts borehole deformation into optical fiber strain by using four rings. For each ring, two FBGs are bonded with the ring to measure the borehole deformation, and a reference FBG free from mechanical load is introduced to remove the temperature effect. Two simple checks on the test data can be performed to improve the test accuracy. Laboratory and field tests were conducted to validate the accuracy and long-term performance of the sensor. The results show that the sensor is capable of measuring stress in rock with good accuracy, and it performs well over a long period of time in coal mines. The developed sensor provides an approach for the long-term monitoring of stress changes in coal mine rock.

Field Tests of a PV-Powered Air Monitoring System

2003 ◽  
Vol 125 (2) ◽  
pp. 203-206 ◽  
Author(s):  
L. Sanidad ◽  
Y. Baghzouz ◽  
R. Boehm ◽  
E. Hodge
Keyword(s):  
Field Tests ◽  
Computer Code ◽  
Test Site ◽  
Weather Data ◽  
Nevada Test Site ◽  
Air Sampler ◽  
Long Term Performance ◽  
Solar Resource ◽  
Term Performance

A compact stand-alone PV power system was recently designed and built to run an air sampler for environmental monitoring at the Nevada Test Site. This paper presents an overview of the system design and analysis of some of the recorded daily cycles of various power flows during the summer period. The system long-term performance during both high and low solar resource periods is simulated with the computer code PVFORM using historical weather data.

Health Monitoring of the Steel Cables Using the Elasto-Magnetic Method

2002 ◽  
Author(s):  
P. Fabo ◽  
A. Jarosevic ◽  
M. Chandoga
Keyword(s):  
Health Monitoring ◽  
Civil Engineering ◽  
Stress Measurement ◽  
Field Tests ◽  
Traffic Load ◽  
Magnetic Method ◽  
Suspension Bridges ◽  
Practical Applications ◽  
Stress Changes ◽  
Long Time

The EM method is a valuable tool for Civil Engineering for estimation of the real stress in the prestressing tendons, quality control during construction period, calculating the stress loss due to friction and relaxation, long-time monitoring of stress changes due to concrete creep, temperature changes, traffic load etc. Overview of EM technique with practical applications in the Civil Engineering is presented. The new generation of EM measuring devices is based on more than 15 years experience, including health monitoring systems for the nuclear power plant and a large span cable stayed and suspension bridges. Examples of laboratory and field tests are presented, including uncertainty of stress measurement, long-time stability, resolution and reliability.

scholarly journals Analysis of Long-Term Prestress Loss in Prestressed Concrete (PC) Structures Using Fiber Bragg Grating (FBG) Sensor-Embedded PC Strands

2021 ◽  
Vol 11 (24) ◽  
pp. 12153
Author(s):  
Sung-Tae Kim ◽  
Young-Soo Park ◽  
Chul-Hwan Yoo ◽  
Soobong Shin ◽  
Young-Hwan Park
Keyword(s):  
Optical Fiber ◽  
Prestressed Concrete ◽  
Optical Fiber Sensor ◽  
Fiber Sensor ◽  
Prestress Loss ◽  
Fbg Sensor ◽  
Embedded Pc ◽  
Long Term Performance ◽  
Term Performance

This study aims to develop a prestressed concrete steel (PC) strand with an embedded optical Fiber Bragg Grating (FBG) sensor, which has been developed by the Korea Institute of Civil Engineering and Building Technology since 2013. This new strand is manufactured by replacing the steel core of the normal PC strand with a carbon-fiber-reinforced polymer (CFRP) rod with excellent tensile strength and durability. Because this new strand is manufactured using the pultrusion method, which is a composite material manufacturing process, with an optical fiber sensor embedded in the inner center of the CFRP Rod, it ensures full composite action as well as proper function of the sensor. In this study, a creep test for maintaining a constant load and a relaxation test for maintaining a constant displacement were performed on the proposed sensor-type PC strand. Each of the two tests was conducted for more than 1000 h, and the long-term performance verification of the sensor-type PC strand was only completed by comparing the performance with that of a normal PC strand. The test specimens were fabricated by applying an optical fiber sensor-embedded PC strand, which had undergone long-term performance verification tests, to a reinforced concrete beam. Depending on whether grout was injected in the duct, the specimens were classified into composite and non-composite specimens. A hydraulic jack was used to prestress the fabricated beam specimens, and the long-term change in the prestress force was observed for more than 1600 days using the embedded optical fiber sensor. The experimental results were compared with the analytical results to determine the long-term prestress loss obtained through finite-element analysis based on various international standards.

Field Tests of a PV-Powered Air Monitoring System

2001 ◽  
Author(s):  
L. Sanidad ◽  
Y. Baghzouz ◽  
R. Boehm ◽  
Earl Hodge
Keyword(s):  
Field Tests ◽  
Computer Code ◽  
Test Site ◽  
Weather Data ◽  
Nevada Test Site ◽  
Air Sampler ◽  
Long Term Performance ◽  
Solar Resource ◽  
Term Performance

Abstract A compact stand-alone PV power system was recently designed and built to run an air sampler for environmental monitoring at the Nevada Test Site. This paper presents an overview of the system design and analysis of some of the recorded daily cycles of various power flows during the summer period. The system long-term performance during both high and low solar resource periods is simulated with the computer code PVFORM using historical weather data.

Test and Research of Long-Term Stress Variation of High-Pier & Long-Span Continuous Rigid-Frame Bridge

2013 ◽  
Vol 639-640 ◽  
pp. 269-273
Author(s):  
Jie Jun Wang ◽  
Min Chen ◽  
Can Bin Yin
Keyword(s):  
Field Tests ◽  
Weather Conditions ◽  
Box Girders ◽  
Stress Variation ◽  
Long Span ◽  
Rigid Frame ◽  
High Pier ◽  
Long Term Performance ◽  
Term Performance

Pre-stressed concrete continuous rigid frame bridges have been widely used for modern long-span bridges due to its advantages, such as comfortable for travelling, easy to be constructed and maintained etc. However, cracks and excessive mid-span sag of box girders generally exist in many built bridges of this kind during service, and because of its large size and the complex natural environment, it is particularly important to study the long-term performance based on the long-term field measurements. In this paper, a high-pier & long-span pre-stressed concrete continuous rigid-frame bridges, with five-spans (106m+3×200m+106m), was taken as the research object, by pre-embedding strain sensors in mid-span sections and root sections on box girders, field-tests for stress variation were conducted in extreme weather conditions (ie, the hottest and coldest in one year) after its completion in two years, providing tested data for studying long-term performance of bridges similar to the same kind.

Development of Elasto-Magneto-Electric (EME) Sensor for In-Service Cable Force Monitoring

2016 ◽  
Vol 16 (04) ◽  
pp. 1640016 ◽  
Author(s):  
Yuan-Feng Duan ◽  
Ru Zhang ◽  
Chuan-Zhi Dong ◽  
Yao-Zhi Luo ◽  
Siu Wing Or ◽  
...  
Keyword(s):  
Stress Measurement ◽  
Signal To Noise Ratio ◽  
Low Cost ◽  
Sensory System ◽  
Steel Structures ◽  
Structural Safety ◽  
Stress Monitoring ◽  
Cable Force ◽  
Force Monitoring

Stress/force monitoring of in-service steel structures is challenging but crucial to the evaluation of structural safety. A smart elasto-magneto-electric (EME) sensor was recently proposed by the authors for stress monitoring of steel components not only with the superiorities of the traditional elasto-magnetic (EM) sensors such as noncontact monitoring, actual-stress measurement, low cost, corrosion resistance and long expected service-life, but also with higher sensitivity, faster response and higher signal-to-noise ratio (SNR). In this paper, the application of the developed EME sensory system on the cable force monitoring of the Second Jiaojiang Bridge in China is presented. Full-scale experiment, factory calibration and in situ verification for engineering applications were successively carried out, which verify that the EME sensor is feasible and reliable to monitor the in-service cable force as a nondestructive testing (NDT) tool. Long-term on-line monitoring of the cable forces is in progress and the typical monitoring data over 7 months are presented and discussed. It is demonstrated that the proposed EME sensor is feasible for the in-service force monitoring of steel cables and that the EME sensory technology is suitable for developing the stable and reliable long-term monitoring system for steel structures.

Fine Particle Mass Monitoring with Low-Cost Sensors: Corrections and Long-Term Performance Evaluation

2019 ◽  
Author(s):  
Carl Malings ◽  
Rebecca Tanzer ◽  
Aliaksei Hauryliuk ◽  
Provat K. Saha ◽  
Allen L. Robinson ◽  
...  
Keyword(s):  
Performance Evaluation ◽  
Fine Particle ◽  
Low Cost ◽  
Particle Mass ◽  
Long Term Performance ◽  
Term Performance

Long-term performance of the Hancock bioprosthetic conduit for aortic root replacement

2008 ◽  
Vol 56 (S 1) ◽  
Author(s):  
CC Badiu ◽  
W Eichinger ◽  
D Ruzicka ◽  
I Hettich ◽  
S Bleiziffer ◽  
...  
Keyword(s):  
Aortic Root ◽  
Aortic Root Replacement ◽  
Long Term Performance ◽  
Term Performance
Sign in / Sign up

Export Citation Format

Share Document