Cure monitoring and structural health monitoring of composites using micro-braided distributed optical fibre

Abstract

In this paper, cure monitoring of a composite laminate is conducted, followed by subsequent structural health monitoring (SHM). A distributed optical fibre (DOF) sensor was embedded between glass fibre fabric plies during manufacture; part of the DOF length was micro-braided using glass fibres, while the remaining length was left 'bare' (as-received condition). In situ and real-time strain measurement during the infusion and curing processes of the laminate was completed. Cure monitoring of composite materials using different fibre orientations, sensor locations, raw materials, and manufacturing methods has been widely studied. However, no consensus was reached due to differences in raw materials, temperature profile, manufacturing method, fibre orientation, and sensor location. The manufactured composite plate was then subjected to repeated loading during a quasi-static four-point bending test, and the strain development along the length of the DOF was recorded. Comparable results were obtained from the micro-braided and bare sections of the DOF, showing the suitability of micro-braided optical fibres for real-time strain monitoring in composite structures. The micro-braiding DOF facilitates handling for automated manufacturing methods and can be used to follow the full life cycle of a composite from fabrication till end-of-life.

Smart Polymer Composite Deck Monitoring Using Distributed High Definition and Bragg Grating Fiber Optic Sensing

“…The ODiSI 6104 HD-FOS incorporates a reflection-suppressing termination and angled physical contact (APC) connectors. It has the ability to measure a strain value range of ±15,000 με, making it suitable for monitoring flexural structures subjected to mechanical and thermal loads [16][17][18][51][52][53][54].…”

In‐situ monitoring of glass fiber/epoxy composites by the embedded multi‐walled carbon nanotube coated glass fiber sensor: From fabrication to application

“…[9,10] Hence, nondestructive techniques (NDTs) are commonly adopted to obtain information on the detection, localization, quantification of flaws, and damage in composites during their fabrication and application. [11] In general, the resin frontal flow and curing process of epoxy resin are monitored by techniques including laser ultrasonics, [12] the resistance of carbon fibers, [13,14] dielectric sensors, [8] resistive heating of carbon nanotube films, [15] piezoelectric sensor networks, [16,17] and optical fibers. [11] Among all the mentioned methods, as Rio et al [14] claimed, electrically resistive sensors could effectively obtain the health information of composites.…”

“…[ 9,10 ] Hence, nondestructive techniques (NDTs) are commonly adopted to obtain information on the detection, localization, quantification of flaws, and damage in composites during their fabrication and application. [ 11 ] In general, the resin frontal flow and curing process of epoxy resin are monitored by techniques including laser ultrasonics, [ 12 ] the resistance of carbon fibers, [ 13,14 ] dielectric sensors, [ 8 ] resistive heating of carbon nanotube films, [ 15 ] piezoelectric sensor networks, [ 16,17 ] and optical fibers. [ 11 ] Among all the mentioned methods, as Rio et al [ 14 ] claimed, electrically resistive sensors could effectively obtain the health information of composites.…”

Comparison of Different Cure Monitoring Techniques

“…This is important if several measurement principles are used together in a later application for the purpose of data fusion. The investigation of strain development during epoxy curing includes one of the more rarely used cure-monitoring techniques [ 78 ], which is also sometimes performed using optical fibres [ 79 ]. The comparison of multiple measurement techniques in the same specimen is new in the extent presented in this article.…”