Early Damage Detection in Composites by Distributed Strain and Acoustic Event Monitoring

Chandarana, Neha; Martinez-Sanchez, Daniel; Soutis, C.; Grésil, Matthieu

doi:10.1016/j.proeng.2017.04.515

Cited by 18 publications

(10 citation statements)

References 27 publications

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“…It was determined that very low strains measured along the length of the 0 fiber direction were obtained in the unidirectional laminate, whereas most of the residual strains developed during cure were in the transverse direction and were spatially uniform, although researchers 16 have also determined that the residual strain is nearly 40% higher near the edge of the laminate and is primarily initiated by the resin-infusion process. Also, optical fibers have been widely used for damage detection [17][18][19][20] and monitoring crack growth 14,21 for structural health monitoring.…”

Section: Introductionmentioning

confidence: 99%

Influence of cure parameters in polymer matrix composites using embedded optical fibers

Drake

Sullivan

Spowart

et al. 2020

Journal of Composite Materials

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The influence of cure processing parameters was investigated using strain distributions from embedded optical fibers. The determination of optimized cure parameters is often needed to achieve material properties which meet aerospace industry design requirements. Optical fibers were embedded near the midplane of thin (5 mm; [0/90/90/0]3s) composite laminates to monitor the internal strain during cure for two different cure cycles (manufacturer-recommended and an alternative two-step cure). Each laminate was fabricated using a vacuum-assisted resin transfer molding process. The internal strain with respect to the spatial position and time were monitored. During cure, greater variations in the strain near the vicinity of the laminate edges were observed. However, a two-step cure cycle revealed that the variation of strain near the laminate edges is reduced. The results demonstrate the capability of high-spatial resolution optical fibers to measure the in-situ cure and residual strain during the processing of composite structures.

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Section: Introductionmentioning

confidence: 99%

Influence of cure parameters in polymer matrix composites using embedded optical fibers

Drake

Sullivan

Spowart

et al. 2020

Journal of Composite Materials

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“…The layered nature of FRP composites allows small sensors to be integrated, thus allowing real time process monitoring. Optical fibres [ 13 , 14 , 15 ] and piezoelectric sensors [ 12 , 16 , 17 , 18 , 19 , 20 ] have been introduced for SHM in composite materials.…”

Section: Introductionmentioning

confidence: 99%

Early Damage Detection in Composites during Fabrication and Mechanical Testing

et al. 2017

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Fully integrated monitoring systems have shown promise in improving confidence in composite materials while reducing lifecycle costs. A distributed optical fibre sensor is embedded in a fibre reinforced composite laminate, to give three sensing regions at different levels through-the-thickness of the plate. This study follows the resin infusion process during fabrication of the composite, monitoring the development of strain in-situ and in real time, and to gain better understanding of the resin rheology during curing. Piezoelectric wafer active sensors and electrical strain gauges are bonded to the plate after fabrication. This is followed by progressive loading/unloading cycles of mechanical four point bending. The strain values obtained from the optical fibre are in good agreement with strain data collected by surface mounted strain gauges, while the sensing regions clearly indicate the development of compressive, neutral, and tensile strain. Acoustic emission event detection suggests the formation of matrix (resin) cracks, with measured damage event amplitudes in agreement with values reported in published literature on the subject. The Felicity ratio for each subsequent loading cycle is calculated to track the progression of damage in the material. The methodology developed here can be used to follow the full life cycle of a composite structure, from manufacture to end-of-life.

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“…Yet, this is a passive approach and for this reason it is subject to its own limitations. On the other hand, the development of structural health monitoring (SHM) techniques, [23][24][25], for composite materials and structures is an emerging technology which seemingly can provide the means to enhance reliability and safety by ensuring early detection and monitoring of damage. Predictive capabilities enabling estimations of residual stiffness and strength of a composite structure with a known state of damage are also emerging.…”

Section: Assessment Of the Health Of A Structurementioning

confidence: 99%

The Structural Integrity of Composite Materials and Long-Life Implementation of Composite Structures

Beaumont

2020

Appl Compos Mater

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Empirical or semi-empirical design methodologies at the macroscopic scale (structural level) can be supported and justified only by a fundamental understanding at the lower (microscopic) size scale through the physical model. Today structural integrity (SI) is thought as the optimisation of microstructure by controlling processing coupled with intelligent manufacturing of the material: to maximise mechanical performance and ensure reliability of the large scale structure; and to avoid calamity and misfortune. SI analysis provides quantitative input to the formulation of an appropriately balanced response to the problem. This article demonstrates that at the heart of the matter are those mechanisms of crack nucleation and growth that affect the structural integrity of the material: microscopic cracking events that are usually too small to observe and viewed only by microscopy.

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Early Damage Detection in Composites by Distributed Strain and Acoustic Event Monitoring

Cited by 18 publications

References 27 publications

Influence of cure parameters in polymer matrix composites using embedded optical fibers

Influence of cure parameters in polymer matrix composites using embedded optical fibers

Early Damage Detection in Composites during Fabrication and Mechanical Testing

The Structural Integrity of Composite Materials and Long-Life Implementation of Composite Structures

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