Toughening mechanisms in cost-effective carbon-epoxy laminates with thermoplastic veils: Mode-I and in-situ SEM fracture characterisation

This study investigates the influence of thermoplastic non-woven veils on the interlaminar fracture energy and toughening mechanisms under mode-I dominant loading conditions in out-of-autoclave resin-infused carbon fibre-epoxy laminates. Two different non-woven micro-fibre veils, Polyetherimide (PEI...

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Main Authors: Oğuzcan İnal, Mehmet Çağatay Akbolat, Constantinos Soutis, Kali Babu Katnam
Format: Article
Language:English
Published: KeAi Communications Co., Ltd. 2021-03-01
Series:International Journal of Lightweight Materials and Manufacture
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S258884042030055X
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spelling doaj-02f417571ecf447586ca9e18e3f4998c2020-12-31T04:43:48ZengKeAi Communications Co., Ltd.International Journal of Lightweight Materials and Manufacture2588-84042021-03-01415061Toughening mechanisms in cost-effective carbon-epoxy laminates with thermoplastic veils: Mode-I and in-situ SEM fracture characterisationOğuzcan İnal0Mehmet Çağatay Akbolat1Constantinos Soutis2Kali Babu Katnam3Department of Materials, The University of Manchester, UKDepartment of Mechanical, Aerospace and Civil Engineering, The University of Manchester, UKDepartment of Materials, The University of Manchester, UK; Aerospace Research Institute, The University of Manchester, UK; Corresponding author. Aerospace Research Institute, The University of Manchester, James Lighthill Building, Sackville Street, Manchester M1 3NJ, UK.Department of Mechanical, Aerospace and Civil Engineering, The University of Manchester, UK; Aerospace Research Institute, The University of Manchester, UKThis study investigates the influence of thermoplastic non-woven veils on the interlaminar fracture energy and toughening mechanisms under mode-I dominant loading conditions in out-of-autoclave resin-infused carbon fibre-epoxy laminates. Two different non-woven micro-fibre veils, Polyetherimide (PEI) and Polyphenylene Sulfide (PPS), of low areal weight (∼10 g/m2) are introduced between carbon fibre non-crimp fabric (NCF) laminae prior to vacuum assisted resin infusion (with a low viscous two-part epoxy resin, i.e. Araldite 564/Aradur 2954). Double Cantilever Beam (DCB) specimens are tested for characterising mode-I fracture energies, and a novel miniature specimen geometry with an embedded fibre-discontinuity to trigger delamination under mode-I dominant loading is employed for in-situ SEM characterisation of micro-damage evolution and toughening mechanisms. The results obtained from DCB specimens showed that the micro-fibre thermoplastic veils considerably improved the mode-I fracture energy when compared with the untoughened fracture energy (i.e. ∼13% increase with PEI and ∼60% with the PPS veils, at the onset of crack propagation). Optical and scanning electron microscopy revealed that the veil parameters such as fibre dispersion, fibre diameter and specific surface area play an important role in enhancing fracture energy. Fracture surface micrographs indicated that progressive fibre-matrix debonding followed by fibre pull-out and fibre bridging resulted in higher fracture energy within the PPS veils. Interleaving a relatively low-cost NCF composite with thermoplastic veils could be as resistant to delamination as aerospace-grade carbon fibre-epoxy systems.http://www.sciencedirect.com/science/article/pii/S258884042030055XInterlaminar fractureThermoplastic interleavingToughening mechanismsMacro-scaleMeso-scaleFibre bridging
collection DOAJ
language English
format Article
sources DOAJ
author Oğuzcan İnal
Mehmet Çağatay Akbolat
Constantinos Soutis
Kali Babu Katnam
spellingShingle Oğuzcan İnal
Mehmet Çağatay Akbolat
Constantinos Soutis
Kali Babu Katnam
Toughening mechanisms in cost-effective carbon-epoxy laminates with thermoplastic veils: Mode-I and in-situ SEM fracture characterisation
International Journal of Lightweight Materials and Manufacture
Interlaminar fracture
Thermoplastic interleaving
Toughening mechanisms
Macro-scale
Meso-scale
Fibre bridging
author_facet Oğuzcan İnal
Mehmet Çağatay Akbolat
Constantinos Soutis
Kali Babu Katnam
author_sort Oğuzcan İnal
title Toughening mechanisms in cost-effective carbon-epoxy laminates with thermoplastic veils: Mode-I and in-situ SEM fracture characterisation
title_short Toughening mechanisms in cost-effective carbon-epoxy laminates with thermoplastic veils: Mode-I and in-situ SEM fracture characterisation
title_full Toughening mechanisms in cost-effective carbon-epoxy laminates with thermoplastic veils: Mode-I and in-situ SEM fracture characterisation
title_fullStr Toughening mechanisms in cost-effective carbon-epoxy laminates with thermoplastic veils: Mode-I and in-situ SEM fracture characterisation
title_full_unstemmed Toughening mechanisms in cost-effective carbon-epoxy laminates with thermoplastic veils: Mode-I and in-situ SEM fracture characterisation
title_sort toughening mechanisms in cost-effective carbon-epoxy laminates with thermoplastic veils: mode-i and in-situ sem fracture characterisation
publisher KeAi Communications Co., Ltd.
series International Journal of Lightweight Materials and Manufacture
issn 2588-8404
publishDate 2021-03-01
description This study investigates the influence of thermoplastic non-woven veils on the interlaminar fracture energy and toughening mechanisms under mode-I dominant loading conditions in out-of-autoclave resin-infused carbon fibre-epoxy laminates. Two different non-woven micro-fibre veils, Polyetherimide (PEI) and Polyphenylene Sulfide (PPS), of low areal weight (∼10 g/m2) are introduced between carbon fibre non-crimp fabric (NCF) laminae prior to vacuum assisted resin infusion (with a low viscous two-part epoxy resin, i.e. Araldite 564/Aradur 2954). Double Cantilever Beam (DCB) specimens are tested for characterising mode-I fracture energies, and a novel miniature specimen geometry with an embedded fibre-discontinuity to trigger delamination under mode-I dominant loading is employed for in-situ SEM characterisation of micro-damage evolution and toughening mechanisms. The results obtained from DCB specimens showed that the micro-fibre thermoplastic veils considerably improved the mode-I fracture energy when compared with the untoughened fracture energy (i.e. ∼13% increase with PEI and ∼60% with the PPS veils, at the onset of crack propagation). Optical and scanning electron microscopy revealed that the veil parameters such as fibre dispersion, fibre diameter and specific surface area play an important role in enhancing fracture energy. Fracture surface micrographs indicated that progressive fibre-matrix debonding followed by fibre pull-out and fibre bridging resulted in higher fracture energy within the PPS veils. Interleaving a relatively low-cost NCF composite with thermoplastic veils could be as resistant to delamination as aerospace-grade carbon fibre-epoxy systems.
topic Interlaminar fracture
Thermoplastic interleaving
Toughening mechanisms
Macro-scale
Meso-scale
Fibre bridging
url http://www.sciencedirect.com/science/article/pii/S258884042030055X
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