Toughening epoxy syntactic foams with milled carbon fibres: Mechanical properties and toughening mechanisms
Syntactic foams comprising hollow glass microspheres (GMS) in an epoxy matrix are critical materials for lightweight structures, being extensively used in marine and aerospace as cores for composite sandwich panels. They are buoyant and crush resistant, but their use is limited by their brittleness....
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| Format: | Article |
| Language: | English |
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Elsevier
2019-05-01
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| Series: | Materials & Design |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0264127519300917 |
| _version_ | 1819045025299824640 |
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| author | Sammy He Declan Carolan Alexander Fergusson Ambrose C. Taylor |
| author_facet | Sammy He Declan Carolan Alexander Fergusson Ambrose C. Taylor |
| author_sort | Sammy He |
| collection | DOAJ |
| description | Syntactic foams comprising hollow glass microspheres (GMS) in an epoxy matrix are critical materials for lightweight structures, being extensively used in marine and aerospace as cores for composite sandwich panels. They are buoyant and crush resistant, but their use is limited by their brittleness. Milled carbon fibres (MCF) were used to increase toughness, by introducing energy absorption mechanisms, to foams comprising ∼60 vol% GMS. Weight ratios of up to 40% MCF:GMS were used. The tensile modulus of the foams increased from 3.36 GPa to 5.41 GPa with the addition of 40% weight ratio of MCF. The tensile strength of the syntactic foam decreased with low loadings of MCF, but then recovers when more MCF particles are added, and the mechanisms responsible are explained for the first time. The fracture energy of the syntactic foam increased by 183%, from 182 J/m2 to 516 J/m2, due to the addition of 40% weight ratio of MCF. Toughening mechanisms were identified as crack deflection, debonding and subsequent plastic void growth, and fibre pull-out. Thus, the simple and cheap addition of MCF greatly increases the toughness of the syntactic foams, enabling lighter or more damage-resistant structures to be produced. Keywords: Syntactic foam, Hollow glass microspheres, Milled carbon fibre, Tension, Fracture, Toughening mechanisms |
| first_indexed | 2024-12-21T10:22:00Z |
| format | Article |
| id | doaj.art-f66a8b7fb49944638793efbe5688987a |
| institution | Directory Open Access Journal |
| issn | 0264-1275 |
| language | English |
| last_indexed | 2024-12-21T10:22:00Z |
| publishDate | 2019-05-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Materials & Design |
| spelling | doaj.art-f66a8b7fb49944638793efbe5688987a2022-12-21T19:07:25ZengElsevierMaterials & Design0264-12752019-05-01169Toughening epoxy syntactic foams with milled carbon fibres: Mechanical properties and toughening mechanismsSammy He0Declan Carolan1Alexander Fergusson2Ambrose C. Taylor3Department of Mechanical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK; Corresponding author.Department of Mechanical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK; FAC Technology, 53 Lydden Grove, Wandsworth, London SW18 4LW, UKDepartment of Mechanical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK; FAC Technology, 53 Lydden Grove, Wandsworth, London SW18 4LW, UKDepartment of Mechanical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UKSyntactic foams comprising hollow glass microspheres (GMS) in an epoxy matrix are critical materials for lightweight structures, being extensively used in marine and aerospace as cores for composite sandwich panels. They are buoyant and crush resistant, but their use is limited by their brittleness. Milled carbon fibres (MCF) were used to increase toughness, by introducing energy absorption mechanisms, to foams comprising ∼60 vol% GMS. Weight ratios of up to 40% MCF:GMS were used. The tensile modulus of the foams increased from 3.36 GPa to 5.41 GPa with the addition of 40% weight ratio of MCF. The tensile strength of the syntactic foam decreased with low loadings of MCF, but then recovers when more MCF particles are added, and the mechanisms responsible are explained for the first time. The fracture energy of the syntactic foam increased by 183%, from 182 J/m2 to 516 J/m2, due to the addition of 40% weight ratio of MCF. Toughening mechanisms were identified as crack deflection, debonding and subsequent plastic void growth, and fibre pull-out. Thus, the simple and cheap addition of MCF greatly increases the toughness of the syntactic foams, enabling lighter or more damage-resistant structures to be produced. Keywords: Syntactic foam, Hollow glass microspheres, Milled carbon fibre, Tension, Fracture, Toughening mechanismshttp://www.sciencedirect.com/science/article/pii/S0264127519300917 |
| spellingShingle | Sammy He Declan Carolan Alexander Fergusson Ambrose C. Taylor Toughening epoxy syntactic foams with milled carbon fibres: Mechanical properties and toughening mechanisms Materials & Design |
| title | Toughening epoxy syntactic foams with milled carbon fibres: Mechanical properties and toughening mechanisms |
| title_full | Toughening epoxy syntactic foams with milled carbon fibres: Mechanical properties and toughening mechanisms |
| title_fullStr | Toughening epoxy syntactic foams with milled carbon fibres: Mechanical properties and toughening mechanisms |
| title_full_unstemmed | Toughening epoxy syntactic foams with milled carbon fibres: Mechanical properties and toughening mechanisms |
| title_short | Toughening epoxy syntactic foams with milled carbon fibres: Mechanical properties and toughening mechanisms |
| title_sort | toughening epoxy syntactic foams with milled carbon fibres mechanical properties and toughening mechanisms |
| url | http://www.sciencedirect.com/science/article/pii/S0264127519300917 |
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