scholarly journals Evaluating the Performance of Functionalized Carbon Structures with Integrated Optical Fiber Sensors under Practical Conditions

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3923 ◽  
Author(s):  
Kort Bremer ◽  
Lourdes Alwis ◽  
Frank Weigand ◽  
Michael Kuhne ◽  
Yulong Zheng ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Concrete Block ◽  
Fiber Optic Sensor ◽  
Bending Test ◽  
Fibre Bragg Grating ◽  
Fiber Sensors ◽  
Carbon Structures ◽  
Custom Made ◽  
Frequency Domain Reflectometry ◽  
Specialized Technique

An Optical Frequency Domain Reflectometry (OFDR) based fiber optic sensor scheme “embedded” in concrete for the purpose of structural health monitoring (SHM) of carbon concrete composites (C3) is presented. The design, while strengthening the concrete structure, also aims to monitor common SHM parameters such as strain and cracks. This was achieved by weaving the carbon fiber together with optical fiber, based on a specialized technique that uses an embroidery setup where both the carbon and optical fiber are woven on a water dissolvable polymer substrate. The performance of the sensing scheme was characterized in-situ utilizing the OFDR based technique and the results presented. The sensors embedded on a custom made concrete block were subjected to varying strain via a three point bending test to destruction and the results discussed. The intended dual-achievement of the scheme thus proposed in SHM and strengthening the C3 is demonstrated. The suitability of the OFDR scheme for C3 is combined with a fibre Bragg grating (FBG)-based approach, and discussed in detail.

scholarly journals Research on the estimation method of the point-of-interest (POI) displacement for ultra-precision flexible motion system based on functional optical fiber sensor

2021 ◽  
Vol 22 ◽  
pp. 48
Author(s):  
Yujie Li ◽  
Ming Zhang ◽  
Yu Zhu
Keyword(s):  
Optical Fiber ◽  
Optical Fiber Sensor ◽  
Estimation Method ◽  
Fiber Optic Sensor ◽  
Fiber Sensor ◽  
Optic Fiber ◽  
Estimation Model ◽  
Fiber Sensors ◽  
Optimal Position ◽  
Displacement Estimation

This paper proposes a POI displacement estimation method based on the functional optical fiber sensor and the phase modulation principle to improve the POI displacement estimation accuracy. First, the relation between the object deformation and the optic fiber lightwave phase is explained; the measurement principle of functional optical fiber sensor based on the heterodyne interference principle and its layout optimization method is proposed, and a POI displacement estimation model is presented based on the data approach. Secondly, a beam is taken as the simulation object, the optimal position and length of the optical fiber sensor are determined based on its simulation data. Finally, the experimental device is designed to verify the effectiveness of the POI displacement estimation method based on the optic fiber sensors. The frequency-domain plot of the signals shows that the optical fiber sensors can express the flexible deformation of the analyzed object well. The POI displacement estimation model with the fiber optic sensor signals as one of the inputs is constructed. Through estimating the test data, the error using the optical fiber sensor-based POI displacement estimation method proposed in this paper reduces by more than 61% compared to the rigid body-based assumption estimation method.

Strain Transfer Analysis for Surface Bonded Fiber Sensor Considering Temperature Influence

2020 ◽  
Author(s):  
Xiaochen Hu ◽  
Zhaoyan Fan
Keyword(s):  
Numerical Model ◽  
Optical Fiber ◽  
Analytical Model ◽  
Optical Fiber Sensors ◽  
Fiber Optic Sensor ◽  
Fiber Sensors ◽  
Strain Transfer ◽  
Transfer Ratio ◽  
Key Characteristics ◽  
Bonding Length

Abstract Strain transfer ratio is one of the key characteristics to determine the accuracy of sensors for strain measurement and structural health monitoring. This paper presented a theoretical study on the strain transfer ratio of optical fiber sensors, which is generally bonded on the surface of target structure by adhesives to measure strain or stress. Compared to the prior efforts where only one type of loads, either mechanical or thermal, is considered, this paper included both of them in the modeling of strain transfer ratio and derived a general analytical expression for their relationships. It has been found that the strain transfer ratio is not a constant in some cases but varies with the strain being measured. The work studied the characteristics of fiber optic sensor in two consecutive approaches: 1) A simplified 2-dimentional multi-layer analytical model was built to derive the expression of strain transfer ratio as a function of the structural and material properties; 2) a numerical model that considers the realistic 3-dimentional structure of the sensor installation scenario was established for validating the analytical model in different case studies. Simulation results have shown that the analytical model matches well with the behavior of strain transfer ratio estimated by the numerical model, with an error less than 1.35%. Based on the validated analytical model, the discussion was further extended to derive the lower limit of the bonding length of optical fiber sensors to satisfy the requirement of measurement accuracy.

scholarly journals Distributed Optical Fiber Sensors Based on Optical Frequency Domain Reflectometry: A review

Sensors ◽  
2018 ◽  
Vol 18 (4) ◽  
pp. 1072 ◽  
Author(s):  
Zhenyang Ding ◽  
Chenhuan Wang ◽  
Kun Liu ◽  
Junfeng Jiang ◽  
Di Yang ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Frequency Domain ◽  
Optical Fiber Sensors ◽  
Optical Frequency ◽  
Fiber Sensors ◽  
Optical Frequency Domain Reflectometry ◽  
Frequency Domain Reflectometry ◽  
Distributed Optical Fiber

scholarly journals Durability of Functionalized Carbon Structures with Optical Fiber Sensors in a Highly Alkaline Concrete Environment

2019 ◽  
Vol 9 (12) ◽  
pp. 2476
Author(s):  
Kort Bremer ◽  
Lourdes S. M. Alwis ◽  
Yulong Zheng ◽  
Frank Weigand ◽  
Michael Kuhne ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Carbon Coating ◽  
Carbon Filament ◽  
Fiber Sensors ◽  
Bending Tests ◽  
Carbon Structures ◽  
Straight Line ◽  
Naoh Solution ◽  
Bonding Length

The paper presents an investigation into the durability of functionalized carbon structures (FCS) in a highly alkaline concrete environment. First, the suitability of optical fibers with different coatings—i.e., acrylate, polyimide, or carbon—for the FCS was investigated by subjecting fibers with different coatings to micro/macro bending and a 5% sodium hydroxide (NaOH) (pH 14) solution. Then, the complete FCS was also subjected to a 5% NaOH solution. Finally, the effects of spatial variation of the fiber embedded in the FCS and the bonding strength between the fiber and FCS was evaluated using different configurations —i.e., fiber integrated into FCS in a straight line and/or with offsets. All three coatings passed the micro/macro bending tests and show degradation after alkaline exposure, with the carbon coating showing least degradation. The FCS showed relative stability after exposure to 5% NaOH. The optimum bonding length between the optical fiber and the carbon filament was found to be ≥150 mm for adequate sensitivity.

Assessing residual stress redistribution during annealing in thick thermoplastic composites using optical fiber sensors

2018 ◽  
Vol 33 (1) ◽  
pp. 53-68 ◽  
Author(s):  
Takuhei Tsukada ◽  
Shu Minakuchi ◽  
Nobuo Takeda
Keyword(s):  
Residual Stress ◽  
Optical Fiber ◽  
Strain Distribution ◽  
Optical Fiber Sensors ◽  
Thermoplastic Composite ◽  
Bending Test ◽  
Degree Of Crystallinity ◽  
Thickness Direction ◽  
Fiber Sensors ◽  
Thick Laminates

In thick thermoplastic composite laminates, nonuniform temperature and cooling rate distribution arises in the through-thickness direction during cost-effective high-rate manufacturing processes. Annealing is often carried out after molding to homogenize degree of crystallinity (DOC) and to reduce residual stress. Even though the change in the residual stress/strain distribution occurring inside thick laminates by this heat treatment is practically important, the changing process and the detailed mechanism are not sufficiently clarified. This present study addresses development and redistribution behavior of residual stress through both molding and annealing using multiple optical fiber sensors deployed in the thickness direction. This article begins by explaining about process monitoring of thick laminates to discuss process-induced strain distribution depending on cooling conditions during molding. Next, strain monitoring is performed during annealing, and the strain change caused by cold crystallization is clarified. Finally, the residual stress distribution is evaluated by a transverse three-point bending test, and the validity of the redistribution mechanism deduced from the strain measurement is confirmed.

scholarly journals Simultaneous Measurement of Distributed Temperature and Strain through Brillouin Frequency Shift Using a Common Communication Optical Fiber

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
Leijun Hu ◽  
Liwen Sheng ◽  
Jisong Yan ◽  
Ligong Li ◽  
Ming Yuan ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Fiber Optic ◽  
Applied Strain ◽  
Fiber Optic Sensor ◽  
Fiber Sensors ◽  
Optic Sensor ◽  
Excellent Candidate ◽  
Potential Applications ◽  
The Difference ◽  
Distributed Strain

A multiparameter Brillouin fiber-optic sensor for distributed strain and temperature information measuring based on spontaneous scattering in a common communication optical fiber (the G. 652. D commercial fiber) is presented and experimentally demonstrated. Benefiting from the difference of the temperature and strain sensitivity from different Brillouin peaks with different acoustic modes, our proposed sensing configuration can be used to distinguish ambient temperature and applied strain at the same time, which is an excellent candidate to address the problem of cross-sensitivity in the classical Brillouin system. In the experimental section, using a 21.8 km sensing length of communication optical fiber, a temperature accuracy of 1.13°C and a strain accuracy of 21.46 με are obtained simultaneously. Considering the performance we achieved now, the proposed innovation and experimental setup will have some potential applications in the field of fiber sensors.

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