Strain Measurements of Composite Laminates with Embedded Fibre Bragg Gratings: Criticism and Opportunities for Research

A holistic approach to strain monitoring in fibre-reinforced polymer composites is presented using embedded fibre Bragg grating sensors. Internal strains are monitored in unidirectional E-glass/epoxy laminate beams during vacuum infusion, curing, post-curing and subsequent loading in flexure until failure. The internal process-induced strain development is investigated through use of different cure schedules and tool/part interactions. The fibre Bragg grating sensors successfully monitor resin flow front progression during infusion, and strain development during curing, representative of the different cure temperatures and tool/part interfaces used. Substantial internal process-induced strains develop in the transverse fibre direction, which should be taken into consideration when designing fibre-reinforced polymer laminates. Flexure tests indicate no significant difference in the mechanical properties of the differently cured specimens, despite the large differences in measured residual strains. This indicates that conventional flexure testing may not reveal residual strain or stress effects at small specimen scale levels. The internal stresses are seen to influence the accuracy of the fibre Bragg gratings within the loading regime. This study confirms the effectiveness of composite life cycle strain monitoring for developing consistent manufacturing processes.

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“…Studies found that good predictions of process strains in neat resin and composite laminates were achievable using a similar setup. 13,16,19 …”

Section: Fbg Sensor Principlementioning

confidence: 99%

Life cycle strain monitoring in glass fibre reinforced polymer laminates using embedded fibre Bragg grating sensors from manufacturing to failure

Nielsen

Schmidt

Høgh

et al. 2013

Journal of Composite Materials

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“…FBG sensors feature many advantages over conventional sensors; they are small, flexible and lightweight, they can be multiplexed and allow quasidistributed sensor configurations, they allow absolute measurements and they have a linear response over a wide temperature and mechanical strain range. These features make FBG sensors highly suitable for integration in a material for smart sensing applications [1][2][3][4].…”

Section: Introductionmentioning

confidence: 99%

Shear stress sensing with Bragg grating-based sensors in microstructured optical fibers

Sulejmani¹,

Sonnenfeld²,

Geernaert³

et al. 2013

Opt. Express

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Abstract:We demonstrate shear stress sensing with a Bragg grating-based microstructured optical fiber sensor embedded in a single lap adhesive joint. We achieved an unprecedented shear stress sensitivity of 59.8 pm/MPa when the joint is loaded in tension. This corresponds to a shear strain sensitivity of 0.01 pm/µε. We verified these results with 2D and 3D finite element modeling. A comparative FEM study with conventional highly birefringent side-hole and bow-tie fibers shows that our dedicated fiber design yields a fourfold sensitivity improvement.

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“…Presently, optical fibre sensors are widely used as an alternative for structural sensing and health monitoring applications in composites, aerospace, marine and civil engineering [59][60][61]. One of the newest application areas for their use is in the railway industry.…”

Section: Strain Gaugementioning

confidence: 99%

State-of-the-Art Review of Railway Track Resilience Monitoring

2018

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Abstract:In recent years, railway systems have played a significant role in transportation systems due to the demand increase in conveying both cargo and passengers. Due to the harsh environments and severe loading conditions, caused by the traffic growth, heavier axles and vehicles and increase in speed, railway tracks are at risk of degradation and failure. Condition monitoring has been widely used to support the health assessment of civil engineering structures and infrastructures. In this context, it was adopted as a powerful tool for an objective assessment of the railway track behaviour by enabling real-time data collection, inspection and detection of structural degradation. According to relevant literature, a number of sensors can be used to monitor track behaviour during the train passing under harsh environments. This paper presents a review of sensors used for structural monitoring of railway track infrastructure, as well as their application to sense the performance of different track components during extreme events. The insight into track monitoring for railways serving traffic with extreme features will not only improve the track inspection and damage detection but also enable a predictive track maintenance regime in order to assist the decision-making process towards more cost-effective management in the railway industry.

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Strain Measurements of Composite Laminates with Embedded Fibre Bragg Gratings: Criticism and Opportunities for Research

Cited by 225 publications

References 116 publications

Life cycle strain monitoring in glass fibre reinforced polymer laminates using embedded fibre Bragg grating sensors from manufacturing to failure

Life cycle strain monitoring in glass fibre reinforced polymer laminates using embedded fibre Bragg grating sensors from manufacturing to failure

Shear stress sensing with Bragg grating-based sensors in microstructured optical fibers

State-of-the-Art Review of Railway Track Resilience Monitoring

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