Thermal apparent-strain sensitivity of surface-adhered, fiber-optic strain gauges

1992 ◽  
Vol 31 (34) ◽  
pp. 7178 ◽  
Author(s):  
Tomas Valis ◽  
Dayle Hogg ◽  
Raymond M. Measures
Keyword(s):  
Fiber Optic ◽  
Strain Gauges ◽  
Strain Sensitivity ◽  
Apparent Strain

Tensoresistive properties of single crystals TlIn1−xGaxSe2

2021 ◽  
pp. 2150201
Author(s):  
Eldar Mehraly Gojayev ◽  
Gulshan Nuraddin Mammadova
Keyword(s):  
Single Crystals ◽  
Solid Solutions ◽  
High Strain ◽  
Sensitivity Coefficient ◽  
Mechanical Deformation ◽  
Static Method ◽  
Strain Gauges ◽  
Strain Sensitivity ◽  
Zone Recrystallization

In this work, single crystals of TlIn[Formula: see text]Ga[Formula: see text]Se2 solid solutions were grown by the methods of zone recrystallization, technologies for the manufacture of strain gauges based on them were developed and the tensoresistive properties of these phases were studied, the coefficient of strain sensitivity was determined by the static method depending on the temperature, the magnitude of mechanical deformation and optical illumination. Revealing that the single crystals have a high strain sensitivity coefficient, by the variation of the composition, quantity of mechanical deformation and the optical illumination, it is possible to control the phase coefficients investigated tensosensitivity.

scholarly journals ANALYSIS OF THE ACCURACY OF FIBRE-OPTIC STRAIN GAUGES

2013 ◽  
Vol 53 (6) ◽  
pp. 872-877
Author(s):  
Dita Jiroutová ◽  
Miroslav Vokáč
Keyword(s):  
Fiber Optic ◽  
Strain Gauges ◽  
Relative Deformation ◽  
Fibre Optic ◽  
Reinforced Concrete Structure ◽  
Structure Monitoring ◽  
Fiber Optic Technology ◽  
Long Term Monitoring ◽  
Term Monitoring

In recent years, the field of structure monitoring has been making increasing use of systems based on fiber-optic technologies. Fiber-optic technology offers many advantages, including higher quality measurements, greater reliability, easier installation and maintenance, insensitivity to the environment (mainly to the electromagnetic field), corrosion resistance, safety in explosive and flammable environments, the possibility of long-term monitoring and lower cost per lifetime. We have used SOFO fibre-optic strain gauges to perform measurements to check the overall relative deformation of a real reinforced concrete structure. Long-term monitoring of the structure revealed that the measurement readings obtained from these fibre-optic strain gauges differed from each other. Greater attention was therefore paid to the calibration of the fibre-optic strain gauges, and to determining their measurement accuracy. The experimental results show that it is necessary to calibrate SOFO strain gauges before they are used, and to determine their calibration constant.

Resistance strain gauges for the measurement of steady strains at temperatures above 650°C

1965 ◽  
Vol 1 (1) ◽  
pp. 11-19 ◽  
Author(s):  
R Bertodo
Keyword(s):  
Longitudinal Axis ◽  
Temperature Gradients ◽  
Moderate Temperature ◽  
Resistance Strain ◽  
Tungsten Alloy ◽  
Strain Gauges ◽  
Strain Sensitivity ◽  
Long Term Stability ◽  
High Electrical Resistivity ◽  
Improved Performance

The paper considers the problem of obtaining steady strain data using electrical resistance strain gauges at temperatures above 650°C, in the presence of moderate temperature gradients, from turbojet components operating in oxidizing environments. The characteristics of forty-six metal and alloy systems are briefly outlined and the properties of platinum, and alloys of face centred cubic platinum metals and metals in the VIa group of the periodic table of elements are discussed in detail. The behaviour of colloidal sols, acid and alkali bonded ceramic cements and flame-sprayed oxides at high temperatures is considered and their effect on the short and long term stability and strain sensitivity of strain gauges presented. Only a limited number of pure oxides possessed an adequately high electrical resistivity at the higher temperatures for use as strain gauge bonding media. Such oxides, when flame-sprayed on to suitably prepared surfaces, developed a bond of sufficient shear strength to transfer the applied strain in a consistent and repeatable manner to the gauge filament. The porosity was low enough to offer some degree of oxidation protection to the strain sensitive grid. The temperature coefficient of resistance, drift rate and strain sensitivity of flat grid, dual-element gauges bonded in this manner to Nimonic specimens are shown and it is concluded that grids of this type, wound from platinum and a commercially available platinum-tungsten alloy, would permit the detection of steady strains within an accuracy of about ±0.5 ton/in2 over the temperature range 600—850°C and within ±1.0 ton/in2 over the approximate range 600—950°C from Nimonic specimens, provided the mean gauge temperature could be determined. Methods of determining this temperature in the presence of moderate temperature gradients along the longitudinal axis of the gauge are discussed and some field data are presented. Drift rates equivalent to less than 0.1 ton/in2/h were noted. It is thought that a coil wound gauge would offer improved performance over a flat grid gauge for temperature gradients across the element, but the problem of providing a suitable former has not been resolved satisfactorily.

scholarly journals Comparison of methods of monitoring structure deformations based on tests of a column-plate slab

2021 ◽  
Vol 20 (4) ◽  
pp. 005-016
Author(s):  
Damian Nykiel
Keyword(s):  
Flat Plate ◽  
Fiber Optic ◽  
Fiber Optic Sensors ◽  
Strain Gauges ◽  
Comparison Of Methods ◽  
Reinforcing Bars ◽  
Monitoring Methods ◽  
Utility Values

This work includes a comparison of the methods of monitoring the deformations of a structure on the example of a flat plate slab test. Classic ESG (electrofusion strain gauges) and modern DFOS (distributed fiber optic sensors) were compared. During the research, both types of sensors were used on some of the reinforcing bars. The study aims to indicate the differences between the compared monitoring methods, both in terms of the obtained results and their utility values.

scholarly journals Monitoring Strategic Hydraulic Infrastructures by Brillouin Distributed Fiber Optic Sensors

Water ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 188
Author(s):  
Manuel Bertulessi ◽  
Daniele Fabrizio Bignami ◽  
Ilaria Boschini ◽  
Marco Brunero ◽  
Maddalena Ferrario ◽  
...  
Keyword(s):  
Fiber Optic ◽  
Fiber Optic Sensors ◽  
Strain Gauges ◽  
Mountain Valley ◽  
Concrete Members ◽  
Strain Monitoring ◽  
Hydropower Plants ◽  
Complex Structural ◽  
Monitoring Technologies

We present a case study of a Structural Health Monitoring (SHM) hybrid system based on Brillouin Distributed Fiber Optic Sensors (D-FOS), Vibrating Wire (VW) extensometers and temperature probes for an existing historical water penstock bridge positioned in a mountain valley in Valle d’Aosta Region, Northwestern Italy. We assessed Brillouin D-FOS performances for this kind of infrastructure, characterized by a complex structural layout and located in a harsh environment. A comparison with the more traditional strain monitoring technology offered by VW strain gauges was performed. The D-FOS strain cable has been bonded to the concrete members using a polyurethane-base adhesive, ensuring a rigid strain transfer. The raw data from all sensors are interpolated on a unique general timestamp with hourly resolution. Strain data from D-FOS and VW strain gauges are then corrected from temperature effects and compared. Considering the inherent differences between the two monitoring technologies, results show a good overall matching between strain time series collected by D-FOS and VW sensors. Brillouin D-FOS proves to be a good solution in terms of performance and economic investment for SHM systems on complex infrastructures such as hydropower plants, which involve extensive geometry combined with the need for detailed and continuous strain monitoring.

Experimental Study of Embedded Fiber‐Optic Strain Gauges in Concrete Structures

1994 ◽  
Vol 120 (8) ◽  
pp. 1696-1717 ◽  
Author(s):  
S. F. Masri ◽  
M. S. Agbabian ◽  
A. M. Abdel‐Ghaffar ◽  
M. Higazy ◽  
R. O. Claus ◽  
...  
Keyword(s):  
Experimental Study ◽  
Fiber Optic ◽  
Concrete Structures ◽  
Strain Gauges

Dynamic load monitoring of composite structures using fiber optic interferometric strain gauges

1994 ◽  
Author(s):  
Norbert Fuerstenau ◽  
Walter Schmidt ◽  
Douglas D. Janzen ◽  
R. Schuetze ◽  
H. C. Goetting
Keyword(s):  
Dynamic Load ◽  
Composite Structures ◽  
Fiber Optic ◽  
Strain Gauges ◽  
Load Monitoring
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