Real-time monitoring for the CFRP/aluminium-alloy bonding structure during curing process using encapsulated fiber Bragg grating sensor

Huang, Jiwei; Zeng, Jie; Bai, Yufang; Wang, Yong; Wang, Ke; Wu, Xiao Chun; Cheng, Zhuming; Liang, Dakai

doi:10.1016/j.yofte.2020.102216

Cited by 11 publications

(10 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…An embedded FBG sensor will generally be subjected to temperature variations and mechanical stresses at the same time. In order to decorrelate the temperature variation from the axial strains measured by the FBG, various methods have been used in the literature, such as: core dopants [24,25], calibration and combined measurements with embedded thermocouples [6,23,38], and encapsulated sensors [27,28,31,39]. In this research, it was decided to encapsulate a calibrated FBG at the end tip of each optical fibre to obtain in-situ temperature measurements and to decorrelate the thermal effect from the axial strain measurements.…”

Section: Methodology and Experimental Set-up For Fbg In-situ Monitoringmentioning

confidence: 99%

“…One of the less intrusive methods available nowadays is the use of optical fibre written with fibre Bragg grating (FBG) sensors. The successful use of such a sensor and its non-intrusiveness for in-situ monitoring has been proved in several studies on composite parts [6,[23][24][25][26][27][28][29] and adhesives [30,31]. FBG sensors are therefore used here to monitor the development of cure-induced strains during a co-bonding process in an autoclave.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Experimental study and in-situ FBG monitoring of process-induced strains during autoclave co-curing, co-bonding and secondary bonding of composite laminates

Moretti

Olivier

Castanié

et al. 2021

Composites Part A: Applied Science and Manufacturing

View full text Add to dashboard Cite

The geometric stability of bonded structural parts, such as self-stiffened panels, is a critical issue in aeronautics.However, autoclave curing and bonding of large complex integrated primary structures often induce distortions compromising their geometric stability. Composite cure-induced strains and distortions have been extensively studied in the literature but the influence of the adhesive on these distortions has often been overlooked. More experimental data are therefore necessary to properly understand its influence on process-induced strains and its behaviour during cure. The present paper reports a wide range of new experimental investigations showing the non-negligible influence of the adhesive on cure-induced distortions of composite assemblies. The experimental data presented include postcure distortion measurements, optical microscope imaging, micro-tomography imaging and FBG in-situ strain monitoring during an autoclave bonding process. These experiments demonstrate the impact of the adhesive film behaviour and of the manufacturing bonding process on final distortions and strains of composite assemblies.

show abstract

Section: Methodology and Experimental Set-up For Fbg In-situ Monitoringmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Experimental study and in-situ FBG monitoring of process-induced strains during autoclave co-curing, co-bonding and secondary bonding of composite laminates

Moretti

Olivier

Castanié

et al. 2021

Composites Part A: Applied Science and Manufacturing

View full text Add to dashboard Cite

show abstract

“…Therefore, this study used the FBG sensor to measure the residual strain of VE resin after curing, correcting for the effect of the temperature. Liang [ 26 ] applied the strain sensitivity coefficient

and temperature sensitivity coefficient

to represent the wavelength shift

affected by the temperature and strain field.

…”

Section: Methodsmentioning

confidence: 99%

“…To measure the resin shrinkage during thermoforming, Boateng [ 25 ] designed different insulation envelopes to envelope the FBG sensor and insulate heat, ensuring that the FBG sensor would only detect the shrinkage of the resin. The design of the insulation envelopes could also be used in the measurement of heterogeneous residual strain; Huang [ 26 ] successfully used FBG and insulation envelopes to monitor the residual strain of a heterogeneous bonding structure. Alcock [ 27 ] used binding agent and a guide-tube to embed FBG sensors into the Li-ion Battery (LIB) surface and monitor the continuous temperature.…”

Section: Introductionmentioning

confidence: 99%

Using a Fiber Bragg Grating Sensor to Measure Residual Strain in the Vacuum-Assisted Resin Transfer Molding Process

2022

View full text Add to dashboard Cite

Vinyl ester (VE) resin has strong environmental tolerance and is the matrix commonly used in the composite materials of fiber-reinforced plastics (FRP). VE resin is often combined with glass fiber in different maritime structures, such as wind turbine blades, spinner cases, and nacelle cases. However, VE resin exhibits exothermic reactions and shrinkage during curing, which often generates residual strain in large structures and those with a high stacking number. This study explored the exothermic reaction and shrinkage of VE resin and glass fiber during the vacuum-assisted resin transfer molding process, as measured using a fiber Bragg grating sensor. The experiment results verified the relationship between the stacking number and residual strain shrinkage. In addition, the symmetric laminate method was used to prevent the bending–twisting coupling effect and subsequent warping deformation of the FRP laminated plate during curing. The experiment results also verified that the bottom layers of the FRP laminated plates produced using VE resin were closer to the mold, and exhibited more shrinkage as the stacking number increased. In addition, this study discovered that during the experiment, the symmetry layer of the FRP laminated plate had a higher exothermic temperature than the bottom layer as a result of the symmetry layer’s ineffective heat dissipation. Therefore, the curing shrinkage of the symmetry layer resin was measured. The experiment results indicated that if the stacking number was between 10 and 30, the residual strain shrinkage of the symmetry layer was greater than that of the surface layer. However, because of the symmetric laminate, the residual strain of the symmetry layer did not increase when the temperature increased. Therefore, the greatest residual strain occurred at the surface of the bottom layer of the laminated plate with a stacking number of 40.

show abstract

“…The effective refractive index of a particular FBG sensor is a constant, while the fiber Bragg grating period is sensitive to temperature and strain changes [ 35 ]:

where

is the Bragg wavelength shift; P e is the photo elastic coefficient of the fiber;

is the strain change along the grating direction;

and

are the thermo expansion coefficient and the thermo-optic coefficient of the fiber, respectively; and ΔT is the change of external temperature. If the temperature is unchanged or compensated using an FBG sensor that is nearby and free of strain change, Equation (2) can be rewritten as:

…”

Section: Theoretic Analysismentioning

confidence: 99%

Monitoring Epoxy Coated Steel under Combined Mechanical Loads and Corrosion Using Fiber Bragg Grating Sensors

Zhang

Huang

et al. 2022

Sensors

View full text Add to dashboard Cite

Fiber Bragg grating (FBG) sensors have been applied to assess strains, stresses, loads, corrosion, and temperature for structural health monitoring (SHM) of steel infrastructure, such as buildings, bridges, and pipelines. Since a single FBG sensor measures a particular parameter at a local spot, it is challenging to detect different types of anomalies and interactions of anomalies. This paper presents an approach to assess interactive anomalies caused by mechanical loading and corrosion on epoxy coated steel substrates using FBG sensors in real time. Experiments were performed by comparing the monitored center wavelength changes in the conditions with loading only, corrosion only, and simultaneous loading and corrosion. The theoretical and experimental results indicated that there were significant interactive influences between loading and corrosion for steel substrates. Loading accelerated the progress of corrosion for the epoxy coated steel substrate, especially when delamination in the epoxy coating was noticed. Through the real-time monitoring from the FBG sensors, the interactions between the anomalies induced by the loading and corrosion can be quantitatively evaluated through the corrosion depth and the loading contact length. These fundamental understandings of the interactions of different anomalies on steel structures can provide valuable information to engineers for better management of steel structures.

show abstract

Real-time monitoring for the CFRP/aluminium-alloy bonding structure during curing process using encapsulated fiber Bragg grating sensor

Cited by 11 publications

References 27 publications

Experimental study and in-situ FBG monitoring of process-induced strains during autoclave co-curing, co-bonding and secondary bonding of composite laminates

Experimental study and in-situ FBG monitoring of process-induced strains during autoclave co-curing, co-bonding and secondary bonding of composite laminates

Using a Fiber Bragg Grating Sensor to Measure Residual Strain in the Vacuum-Assisted Resin Transfer Molding Process

Monitoring Epoxy Coated Steel under Combined Mechanical Loads and Corrosion Using Fiber Bragg Grating Sensors

Contact Info

Product

Resources

About