13 documents found, page 1 of 2
New embeddable layer concept for real-time monitoring on composite materials
Correia, J.; Rocha, Helena Cristina Lopes; Alves, R.; Nunes, J. P.; Viana, J. C.Nowadays, the broad application of composite materials in high profile engineering structures demands the use of real-time monitoring methods to ensure they are behaving in accordance with their mechanical design and in order to avoid any eventual unpredictable failure [1]. The current work presents new layer concepts to be embedded within composite laminate structures with the purpose of monitoring them in rea...
Processing and structural health monitoring of a composite overwrapped pressure...
Rocha, Helena Cristina Lopes; Antunes, Paulo; Lafont, Ugo; Nunes, J. P.A process and Structural Health Monitoring system was implemented on a Composite Overwrapped Pressure Vessel (COPV) for hydrogen storage at 350 bar to be used in a fuel-cell system of an Unmanned Aerial Vehicle. This work reports the embedment strategy of optical fibre Bragg grating (FBG) sensors to monitor the full life cycle of the vessel, consisting of an aluminium liner and a wound carbon fibre reinforced p...
Process and structural health monitoring of a composite overwrapped pressure ve...
Rocha, Helena Cristina Lopes; Antunes, P.; Lafont, U.; Nunes, J. P.Replacements for fossil fuels in the transportation industry are being explored, to restrain global warming. Hydrogen-powered fuel cell systems, with Composite Overwrapped Pressure Vessels (COPVs) for hydrogen storage, are regarded as a viable alternative energy solution. COPVs, which consist of a fibre reinforced polymer composite overwrap wound around a liner, are the most weight efficient pressure vessel sol...
Smart composite parts with multifunctional properties ready to fly
Rocha, Helena Cristina LopesA utilização de compósitos poliméricos, em aplicações estruturais avançadas nas indústrias aeroespacial e aeronáutica, sofreu um forte aumento nas últimas décadas. Estes materiais têm substituído os metais, com o objetivo de aumentar as propriedades mecânicas a uma baixa massa e, consequentemente, reduzir o consumo de combustível, emissões de CO2 e custos. Comparativamente aos metais, que geralmente falham devi...
FBG sensors for process and structural health monitoring of a small type III co...
Rocha, Helena Cristina Lopes; Antunes, Paulo; Lafonte, Ugo; Nunes, J. P.In this work, fibre Bragg grating (FBG) sensors were embedded in a 1-litre type III composite overwrapped pressure vessel (COPV) for an unmanned aerial vehicle (UAV), during its manufacturing for process and structural health monitoring (SHM). A single optical fibre having eight FBG sensors was fixed around an aluminium liner to form a grid network. The carbon fibre/epoxy composite layers were wound on top of i...
Damage localization on CFRP composites by electrical impedance tomography
Rocha, Helena Cristina Lopes; Fernandes, Christophe; Ferreira, Nelson; Lafont, Ugo; Nunes, J. P.This work exploited the use of electrical impedance tomography (EIT) with one-step difference Gaussian-Newton (GN) algorithm to detect different types of damage on unidirectional carbon fibre/epoxy composite laminates. The major challenge concerning the implementation of EIT on composite materials has to do with their anisotropy. To assess this issue, this study was conducted on carbon fibre composites having d...
Electrical impedance tomography for damage detection and localization on carbon...
Rocha, Helena Cristina Lopes; Fernandes, Christophe; Ferreira, Nelson; Lafont, Ugo; Nunes, João P.Electrical impedance tomography (EIT) is being developed as promising non-intrusive technology for damage detection in conductive fibre reinforced polymers (FRP) composites. This work assessed EIT and one-step difference Gaussian-Newton algorithm to detect different damages in CFRP laminates, including through-thickness holes and impact damage of different severities. Two layup laminates were studied: quasi-iso...
Sensors for process and structural health monitoring of aerospace composites: a...
Rocha, Helena Cristina Lopes; Semprimoschnig, Christopher; Nunes, J. P.Structural Health Monitoring (SHM) is a promising approach to overcome the unpredictable failure behaviour of composite materials and further foster their use in aerospace industry with increased confidence. SHM may require a complex system, including sensors, wiring and cabling, data acquisition devices and software, data storage equipment, power equipment and algorithms for signal processing, involving a mult...
Optimisation of through-thickness embedding location of Fibre Bragg grating sen...
Rocha, Helena Cristina Lopes; Lafont, Ugo; Nunes, J. P.Aerospace composites are susceptible to barely visible impact damage (BVID) produced by low-velocity-impact (LVI) events. Fibre Bragg grating (FBG) sensors can detect BVID, but often FBG sensors are embedded in the mid-plan, where residual strains produced by impact damage are lower, leading to an undervaluation of the damage severity. This study compares the residual strains produced by LVI events measured by ...
Small-diameter optical fibre sensor embedment for ambient temperature cure moni...
Rocha, Helena Cristina Lopes; Semprimoschnig, Christopher; Nunes, J. P.Out of autoclave (OoA) processing techniques, such as liquid composite moulding techniques (LCM) and, particularly, the vacuum assisted resin infusion (VARI) technique, are being used, with increasing success, in replacement of prepreg/autoclave technologies to produce structural aircraft/aerospace polymer composite parts, due to its better cost effectiveness and competitiveness. This work aims to embed Fibre B...