scholarly journals Shape Sensing with Rayleigh Backscattering Fibre Optic Sensor

Sensors ◽  
2020 ◽  
Vol 20 (14) ◽  
pp. 4040
Author(s):  
Cheng Xu ◽  
Zahra Sharif Khodaei
Keyword(s):  
High Reliability ◽  
Complex Loading ◽  
Transformation Method ◽  
Combine Loading ◽  
Fibre Bragg Grating ◽  
Fibre Optic ◽  
Strain Sensing ◽  
Rayleigh Backscattering ◽  
Validation Experiment ◽  
Shape Sensing

In this paper, Rayleigh backscattering sensors (RBS) are used to realize shape sensing of beam-like structures. Compared to conventional shape sensing systems based on fibre Bragg grating (FBG) sensors, RBS are capable of continuous lateral sensing. Compared to other types of distributed fibre optic sensors (FOS), RBS have a higher spatial resolution. First, the RBS’s strain sensing accuracy is validated by an experiment comparing it with strain gauge response. After that, two shape sensing algorithms (the coordinate transformation method (CTM) and the strain-deflection equation method (SDEM)) based on the distributed FOS’ input strain data are derived. The algorithms are then optimized according to the distributed FOS’ features, to make it applicable to complex and/or combine loading situations while maintaining high reliability in case of sensing part malfunction. Numerical simulations are carried out to validate the algorithms’ accuracy and compare their accuracy. The simulation shows that compared to the FBG-based system, the RBS system has a better performance in configuring the shape when the structure is under complex loading. Finally, a validation experiment is conducted in which the RBS-based shape sensing system is used to configure the shape of a composite cantilever-beam-like specimen under concentrated loading. The result is then compared with the optical camera-measured shape. The experimental results show that both shape sensing algorithms predict the shape with high accuracy comparable with the optical camera result.

Integrity Assurance of an Oil Transportation Pipeline in a Transformed Design Environment

2015 ◽  
Author(s):  
Amitabh Kumar ◽  
Brian McShane ◽  
Mark McQueen
Keyword(s):  
Field Data ◽  
Oil And Gas ◽  
High Reliability ◽  
Complex Loading ◽  
Calibration Method ◽  
Real Field ◽  
Design Environment ◽  
Data Feedback ◽  
Integrity Management

A large Oil and Gas pipeline gathering system is commonly used to transport processed oil and gas from an offshore platform to an onshore receiving facility. High reliability and integrity for continuous operation of these systems is crucial to ensure constant supply of hydrocarbon to the onshore processing facility and eventually to market. When such a system is exposed to a series of complex environmental loadings, it is often difficult to predict the response path, in-situ condition and therefore the system’s ability to withstand subsequent future loading scenarios. In order to continue to operate the pipeline after a significant environmental event, an overall approach needs to be developed to — (a) Understand the system loading and the associated integrity, (b) Develop a series of criteria staging the sequence of actions following an event that will verify the pipeline integrity and (c) Ensure that the integrity management solution is simple and easy to understand so that it can be implemented consistently. For a complex loading scenario, one of the main challenges is the ability to predict the controlling parameter(s) that drives the global integrity of these systems. In such scenarios, the presence of numerous parameters makes the technical modeling and prediction tasks arduous. To address such scenarios, first and foremost, it is crucial to understand the baseline environment data and other associated critical design input elements. If the “design environmental baseline” has transformed (due to large events e.g. storms etc.) from its original condition; it modifies the dynamics of the system. To address this problem, a thorough modeling and assessment of the in-situ condition is essential. Further, a robust calibration method is required to predict the future response path and therefore expected pipeline condition. The study further compares the planned integrity management solutions to the field data to validate the efficiency of the predicted scenarios. By the inclusion of real field-data feedback to the modeling method, balanced integrity solutions can be achieved and the ability to quantify the risks is made more practical and actionable.

scholarly journals Fibre optic sensing of ageing railway infrastructure enhanced with statistical shape analysis

2020 ◽  
Author(s):  
Haris Alexakis ◽  
F. Din-Houn Lau ◽  
Matthew J. DeJong
Keyword(s):  
Shape Analysis ◽  
Sensor Data ◽  
Dynamic Strain ◽  
Support Vector ◽  
Fibre Bragg Grating ◽  
Statistical Shape Analysis ◽  
Fibre Optic ◽  
Railway Infrastructure ◽  
Statistical Shape ◽  
Train Speed

Abstract Developing early-warning sensor-based maintenance systems for ageing railway infrastructure, such as masonry arch bridges, can be a challenging task due to the difficulty of identifying degradation/damage as the source of small, gradual changes in sensor data, as opposed to other environmental and loading effects. This paper offers a new method of applying statistical modelling and machine learning to enhance the interpretation of fibre optic sensing data, and, therefore, improve deterioration monitoring of railway infrastructure. Dynamic strain and temperature monitoring data between 2016 and 2019 from a fibre Bragg grating (FBG) network installed in a Victorian railway viaduct are first presented. The statistical shape analysis adopted in this study is modified to track changes in the shape of FBG signals directly linked to train speed and dynamic strain amplitudes. The method is complemented by a support vector machine, which is trained to identify different classes of trains. After distinguishing train types, dynamic strain was found to be clearly correlated to temperature, verifying previous findings. No correlation with train speed was observed. The integrated system is then able to compensate for changes in the structural performance due to variations in train loading and ambient temperature, and identify changes in dynamic deformation caused by degradation, in an order comparable to the signal noise (± 2 micro-strain). As a result, the new procedure is shown to be capable of detecting small magnitudes of local degradation well before this degradation manifests itself in typical global measures of response.

Embedded fibre Bragg grating sensors for non-uniform strain sensing in composite structures

2005 ◽  
Vol 16 (12) ◽  
pp. 2415-2424 ◽  
Author(s):  
Hang-yin Ling ◽  
Kin-tak Lau ◽  
Li Cheng ◽  
Kwok-wing Chow
Keyword(s):  
Composite Structures ◽  
Uniform Strain ◽  
Bragg Grating ◽  
Fibre Bragg Grating ◽  
Strain Sensing

Leak detection on water pipelines in unsaturated ground by discrete fibre optic sensing

2019 ◽  
Vol 19 (4) ◽  
pp. 1219-1236 ◽  
Author(s):  
Schalk Willem Jacobsz ◽  
Sebastian Ingo Jahnke
Keyword(s):  
Unsaturated Soil ◽  
Ground Deformation ◽  
Bragg Gratings ◽  
Leak Detection ◽  
Bragg Grating ◽  
Fibre Bragg Grating ◽  
Fibre Optic ◽  
Temperature Changes ◽  
Water Leak ◽  
Fibre Bragg Gratings

The article describes a study using discrete fibre optic sensing as a means of leak detection on water distribution pipes installed in unsaturated ground. A short length of pipe fitted with artificial leak points was installed, to which a fibre optic cable with fibre Bragg gratings was attached. An optical fibre with fibre Bragg gratings was also installed in the ground parallel to but separate from the pipe. Thermistors were installed at selected locations to measure temperature changes independent of strain. It was found that a simulated water leak resulted in clearly detectable temperature changes and thermally induced fibre Bragg grating wavelength changes in the ground around the pipe. However, significantly larger deformation-induced fibre Bragg grating wavelength changes were measured on the pipe walls and also in the initially unsaturated ground in response to leaks. A wetting front originating from a water leak propagating through unsaturated soil is associated with significant effective stress changes because the infiltrating water alters the ambient matric suction in the soil. This effective stress change is associated with significant ground deformation resulting in a fibre Bragg grating response which significantly exceeds the thermal response associated with (usually) colder water leaking into unsaturated soil. The study illustrates advantages of measuring ground deformation-induced fibre Bragg grating wavelength changes over pure temperature changes as an efficient means of leak detection in unsaturated ground. However, due to the limited number of fibre Bragg gratings that can be monitored along a single optical fibre, a leak detection system suitable for practical implementation should be based on distributed fibre optic strain sensing, an aspect requiring further research.

scholarly journals Recent developments in fibre optic shape sensing

Measurement ◽  
2018 ◽  
Vol 128 ◽  
pp. 119-137 ◽  
Author(s):  
Moe Amanzadeh ◽  
Saiied M. Aminossadati ◽  
Mehmet S. Kizil ◽  
Aleksandar D. Rakić
Keyword(s):  
Fibre Optic ◽  
Recent Developments ◽  
Shape Sensing
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