Spatially continuous strain monitoring using distributed fiber optic sensors embedded in carbon fiber composites

Jothibasu, Sasi; Du, Yu; Anandan, Sudharshan; Dhaliwal, Gurjot S.; Gerald, Rex E.; Watkins, Steve Eugene; Chandrashekhara, K.; Huang, Jie

doi:10.1117/1.oe.58.7.072004

Cited by 11 publications

(7 citation statements)

References 34 publications

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“…The feature becomes more obvious as the gradient value

is high, which is because the coefficient of thermal expansion of the matrix increases with the increase of temperature, and this trend is more prominent at

than that at

. Although there is lack of the experiment observations for direct comparison, the thermoelastic strain induced by linear gradient temperature considered here is in analogy with the almost linear gradient bending strain in a small region measured for a cantilever [ 36 ]. Additionally, due to boundary conditions of sensing structure, the deformation of the fiber core is forced to zero at both ends.…”

Section: Resultsmentioning

confidence: 99%

Strain Transfer Characteristics of Multi-Layer Optical Fiber Sensors with Temperature-Dependent Properties at Low Temperature

Yang

Wang

2021

Sensors

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Optical fiber sensors have been potentially expected to apply in the extreme environment for their advantages of measurement in a large temperature range. The packaging measure which makes the strain sensing fiber survive in these harsh conditions will commonly introduce inevitable strain transfer errors. In this paper, the strain transfer characteristics of a multi-layer optical fiber sensing structure working at cryogenic environment with temperature gradients have been investigated theoretically. A generalized three-layer shear lag model incorporating with temperature-dependent properties of layers was developed. The strain transfer relationship between the optical fiber core and the matrix has been derived in form of a second-order ordinary differential equation (ODE) with variable coefficients, where the Young’s modulus and the coefficients of thermal expansion (CTE) are considered as functions of temperature. The strain transfer characteristics of the optical sensing structure were captured by solving the ODE boundary problems for cryogenic temperature loads. Case studies of the cooling process from room temperature to some certain low temperatures and gradient temperature loads for different low-temperature zones were addressed. The results showed that different temperature load configurations cause different strain transfer error features which can be described by the proposed model. The protective layer always plays a main role, and the optimization geometrical parameters should be carefully designed. To verify the theoretical predictions, an experiment study on the thermal strain measurement of an aluminum bar with optical fiber sensors was conducted. LUNA ODiSI 6100 integrator was used to measure the Rayleigh backscattering spectra shift of the optical fiber at a uniform temperature and a gradient temperature under liquid nitrogen temperature zone, and a reasonable agreement with the theory was presented.

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“…The feature becomes more obvious as the gradient value

is high, which is because the coefficient of thermal expansion of the matrix increases with the increase of temperature, and this trend is more prominent at

than that at

Section: Resultsmentioning

confidence: 99%

Strain Transfer Characteristics of Multi-Layer Optical Fiber Sensors with Temperature-Dependent Properties at Low Temperature

Yang

Wang

2021

Sensors

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“…The resolution achievable with multiplexed FBG or other multiple sensors is restricted to the geometric properties of the fibre or the individual sensor. This would still allow for blind spots where a potential strain build-up would not be detected [4]. Distributed fibre optic sensors (FOS) provide a spatially continuous measurement, eliminating blind spots caused by sensor spacing.…”

Section: Using Optical Fibres As Sensorsmentioning

confidence: 99%

“…In composite applications, the fibre can therefore be directly integrated into the composite structure during manufacturing. It is shown in Jothibasu et al [4] that with sufficient thickness of the core, the sensor fibre is not influenced by slight deformations of the coating which might occur during the manufacturing process. Furthermore, the seamless integration of the sensor does not interfere with the behaviour of the composite.…”

Section: Strain Measurement Using Optical Fibresmentioning

confidence: 99%

Deformation measurement within adhesive bonds of aluminium and CFRP using advanced fibre optic sensors

et al. 2020

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Monitoring the deformation within an adhesive joint during the curing cycle provides valuable information regarding the build-up of thermal strain and stress. Distributed fibre optic sensors are very useful for spatial continuous measurements of deformation or temperature. Integrated into a hybrid joint, the thermal curing process of the adhesive can be monitored. This detailed insight into the joint helps to understand the deformation and thereby also the resulting stress. Analysing the deformation process establishes the foundation to adapt techniques to reduce the thermally induced deformation and thereby the resulting stress.

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“…In recent years, researchers have proposed a variety of composite monitoring and sensing technologies. However, some of these technologies, such as ultrasonic technology, cannot be applied in the mechanical operation of composite materials, while other technologies, such as active piezoelectric sensors, optical fiber sensors, acoustic emission sensors, and other embedded sensing technologies, can monitor the composite structure in real time [4][5][6]. For the manufacturing methods, identifiability and damage types of composite materials, each different monitoring technology, have their own advantages and disadvantages.…”

Section: Introductionmentioning

confidence: 99%

Strain-Sensing Characteristics of Carbon Nanotube Yarns Embedded in Three-Dimensional Braided Composites under Cyclic Loading

Bai

Ding

Jia

et al. 2021

Discrete Dynamics in Nature and Society

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Carbon nanotube yarns are embedded in three-dimensional (3D) braided composites with five-axis yarns, which are used as strain sensors to monitor the damage of 3D braided composites. In the cyclic mechanical loading experiment, the strain-sensing characteristics of 3D braided composites were studied by in situ measuring the resistance change of the embedded carbon nanotube yarn. The 3D five-directional braided composite prefabricated part based on carbon nanotube yarns was developed, and the progressive damage accumulation experiments were carried out on carbon nanotube yarns and specimens embedded in carbon nanotube yarns. The research results show that there is a good correlation between the change of relative resistance of the carbon nanotube yarn and the strain of the composite specimen during cyclic loading and unloading. When the tensile degree of the specimen increases beyond a certain range, the carbon nanotube yarn sensor embedded in the specimen shows resistance hysteresis and produces residual resistance. Therefore, the fiber can better monitor the progressive damage accumulation of 3D five-direction braided composites.

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Spatially continuous strain monitoring using distributed fiber optic sensors embedded in carbon fiber composites

Cited by 11 publications

References 34 publications

Strain Transfer Characteristics of Multi-Layer Optical Fiber Sensors with Temperature-Dependent Properties at Low Temperature

Strain Transfer Characteristics of Multi-Layer Optical Fiber Sensors with Temperature-Dependent Properties at Low Temperature

Deformation measurement within adhesive bonds of aluminium and CFRP using advanced fibre optic sensors

Strain-Sensing Characteristics of Carbon Nanotube Yarns Embedded in Three-Dimensional Braided Composites under Cyclic Loading

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