Relaxation of thermal stresses in double-coated optical fibers

1999 ◽  
Vol 86 (8) ◽  
pp. 4085-4090 ◽  
Author(s):  
Sham-Tsong Shiue ◽  
Yuan-Kuang Tu
Keyword(s):  
Optical Fibers ◽  
Thermal Stresses

Effect of coating thickness on thermal stresses in tungsten-coated optical fibers

2000 ◽  
Vol 87 (8) ◽  
pp. 3759-3762 ◽  
Author(s):  
Sham-Tsong Shiue ◽  
Pin-Tzu Lien ◽  
J.-L. He
Keyword(s):  
Optical Fibers ◽  
Coating Thickness ◽  
Thermal Stresses

Thermal stresses in metal-coated optical fibers

1998 ◽  
Vol 83 (11) ◽  
pp. 5719-5723 ◽  
Author(s):  
Sham-Tsong Shiue ◽  
Yi-Shyang Lin
Keyword(s):  
Optical Fibers ◽  
Thermal Stresses

Thermal stresses in carbon-coated optical fibers at low temperature

1997 ◽  
Vol 12 (9) ◽  
pp. 2493-2498 ◽  
Author(s):  
Sham-Tsong Shiue ◽  
Wen-Hao Lee
Keyword(s):  
Thermal Stress ◽  
Low Temperature ◽  
Glass Fiber ◽  
Young’S Modulus ◽  
Optical Fibers ◽  
Poisson’S Ratio ◽  
Carbon Coating ◽  
Thermal Stresses ◽  
Poisson's Ratio ◽  
Carbon Coated

The thermal stresses in carbon-coated optical fibers at low temperature have been analyzed. The thermally induced lateral pressure in the glass fiber would produce microbending loss. In order to minimize such a microbending loss, the thickness, Young's modulus, and Poisson's ratio of the carbon coating should be decreased. On the other hand, the maximum thermal stress is the tangential stress in the carbon coating that occurs at the interface of the carbon coating and glass fiber. It was experimentally observed that if the maximum thermal stress is larger than the tensile strength of the carbon coating, the carbon coating will be broken along the axial direction. In order to minimize such a maximum thermal stress, the thickness of the carbon coating should be increased, but Young's modulus, thermal expansion coefficient, and Poisson's ratio of the carbon coating should be decreased. Finally, an optimal selection of the carbon coating for optical fiber is discussed.

Thermal stresses in double‐coated optical fibers at low temperature

1992 ◽  
Vol 72 (1) ◽  
pp. 18-23 ◽  
Author(s):  
Sham‐Tsong Shiue ◽  
Sanboh Lee
Keyword(s):  
Low Temperature ◽  
Optical Fibers ◽  
Thermal Stresses

Thermal stresses in hermetically double-coated optical fibers

1999 ◽  
Vol 85 (6) ◽  
pp. 3044-3050 ◽  
Author(s):  
Sham-Tsong Shiue
Keyword(s):  
Optical Fibers ◽  
Thermal Stresses

A Decade of Pipeline Geotechnical Monitoring Using Distributed Fiber Optic Monitoring Technology

2017 ◽  
Author(s):  
Fabien Ravet ◽  
Marc Niklès ◽  
Etienne Rochat
Keyword(s):  
Optical Fibers ◽  
Thermal Stresses ◽  
Brillouin Scattering ◽  
Weather Conditions ◽  
Spatial Location ◽  
Deformation Monitoring ◽  
Geotechnical Monitoring ◽  
The Andes ◽  
Distributed Measurement ◽  
Event Quantification

Many pipelines are built in regions affected by harsh environmental conditions where changes in soil texture between winter and summer increase the likelihood of risks. Pipeline routes also cross the mountains that are characterized by steep slopes and unstable soils as in the Andes and along the coastal range of Brazil. In other cases, these pipelines are laid in remote areas with significant seismic activity or exposure to permafrost. Depending on weather conditions and location, visual inspection is difficult or even impossible and therefore remote sensing solutions for pipes offer significant advantages over conventional inspection techniques. Optical fibers can help solve these challenges. Optical fiber based geotechnical and structural monitoring use distributed measurement of strain and temperature thanks to the sensitivity of Brillouin scattering to mechanical and thermal stresses. The analysis of scattering combined with a time domain technique allows the measurement of strain and temperature profiles. Temperature measurement is carried out to control soil erosion or dune migration through event quantification and spatial location. Direct measurement of strain in the soil also improves the detection of environmental hazards. As an example the technology can pinpoint the early signs of landslide. In some cases, pipe actual deformation must be monitored such as in case of active tectonic fault crossing. Pipe deformation monitoring operation is achieved by the measurement of distributed strain along fiber sensors attached to the structure. This paper comprehensively reviews over 10 years of continuous development from technology qualification and validation to its implementation in real cases as well as its successful continuous operation. Case studies present pipeline monitoring in Arctic and Siberian environment as well as in the Andes. They illustrate how the technology is used and demonstrate proof of early detection and location of events such as erosion, landslide, subsidence and pipe deformation.

Deformation at interfaces of Ti-6Al-4V/SiC fiber composites

1992 ◽  
Vol 50 (1) ◽  
pp. 158-159
Author(s):  
Warren J. Moberly ◽  
Daniel B. Miracle ◽  
S. Krishnamurthy
Keyword(s):  
Thermal Stresses ◽  
Load Transfer ◽  
Coefficient Of Thermal Expansion ◽  
Hot Isostatic Pressing ◽  
Matrix Composites ◽  
Ongoing Research ◽  
Aerospace Applications ◽  
Sic Fiber ◽  
The Matrix ◽  
Intermetallic Matrix Composites

Titanium-aluminum alloy metal matrix composites (MMC) and Ti-Al intermetallic matrix composites (IMC), reinforced with continuous SCS6 SiC fibers are leading candidates for high temperature aerospace applications such as the National Aerospace Plane (NASP). The nature of deformation at fiber / matrix interfaces is characterized in this ongoing research. One major concern is the mismatch in coefficient of thermal expansion (CTE) between the Ti-based matrix and the SiC fiber. This can lead to thermal stresses upon cooling down from the temperature incurred during hot isostatic pressing (HIP), which are sufficient to cause yielding in the matrix, and/or lead to fatigue from the thermal cycling that will be incurred during application, A second concern is the load transfer, from fiber to matrix, that is required if/when fiber fracture occurs. In both cases the stresses in the matrix are most severe at the interlace.

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