Publications
236 results found
Snyder J, Gienger E, Wetzel E, et al., 2010, Multifunctional Structural Composite Supercapacitors, Proceedings of 27th U.S. Army Science Conference. -
We are developing structural polymeric composites with supercapacitor functionality. These devices carry structural loads while simultaneously storing electrochemical energy. If designed with sufficient structural and energy efficiency, these materials could enable significant system-level weight reductions by replacing inert structural components while providing supplementary power for light load applications. To enable this concept, we have designed mechanical loadbearing properties directly into the supercapacitor electrodes and electrolyte such that each component is itself multifunctional. Several electrode types are evaluated here for multifunctional properties in a structural composite supercapacitor configuration. The resulting supercapacitor composites have been characterized to quantifiably compare changes in materials and processing, including tensile and shear tests to assess mechanical properties, and cyclic voltammetry to assess energy storage behavior.
Nguyen SN, Greenhalgh ES, Olsson R, et al., 2010, Parametric analysis of runway stone lofting mechanisms, INTERNATIONAL JOURNAL OF IMPACT ENGINEERING, Vol: 37, Pages: 502-514, ISSN: 0734-743X
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- Citations: 6
Qian H, Bismarck A, Greenhalgh ES, et al., 2010, Carbon nanotube grafted silica fibres: Characterising the interface at the single fibre level, COMPOSITES SCIENCE AND TECHNOLOGY, Vol: 70, Pages: 393-399, ISSN: 0266-3538
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- Citations: 92
Qian H, Bismarck A, Greenhalgh ES, et al., 2010, Carbon nanotube grafted silica fibres: Characterising the interface at the single fibre level, Composites Science and Technology, Vol: 70, Pages: 393-399
Model polymer composites containing carbon nanotube (CNT) grafted fibres provide a means to investigate the influence of nanostructures on interfacial properties. Well-aligned nanotubes, with controllable length, were grown on silica fibres by using the injection chemical vapour deposition method, leading to a significant increase of the fibre surface area. In single fibre tensile tests, this CNT growth reaction reduced the fibre strength, apparently due to catalyst etching; however, the fibre modulus increased significantly. Contact angle measurements, using the drop-on-fibre method, indicated an excellent wettability of the CNT-grafted fibres by poly(methyl methacrylate) (PMMA). PMMA model composites were fabricated and studied using the single fibre fragmentation tests. A dramatic improvement (up to 150%) of the apparent interfacial shear strength (IFSS) was obtained for the composites containing CNT-grafted fibres. The improvement of IFSS was also influenced by the length and morphology of the grafted CNTs. (C) 2009 Elsevier Ltd. All rights reserved.
Qian H, Bismarck A, Greenhalgh ES, et al., 2010, Synthesis and characterisation of carbon nanotubes grown on silica fibres by injection CVD, CARBON, Vol: 48, Pages: 277-286, ISSN: 0008-6223
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- Citations: 57
Qian H, Greenhalgh ES, Shaffer MSP, et al., 2010, Carbon nanotube-based hierarchical composites: a review, Journal of Materials Chemistry
The introduction of carbon nanotubes (CNTs) into conventional fibre-reinforced polymer composites creates a hierarchical reinforcement structure and can significantly improve composite performance. This paper reviews the progress to date towards the creation of fibre reinforced (hierarchical) nanocomposites and assesses the potential for a new generation of advanced multifunctional materials. Two alternative strategies for forming CNT-based hierarchical composites are contrasted, the dispersion of CNTs into the composite matrix and their direct attachment onto the primary fibre surface. The implications of each approach for composite processing and performance are discussed, along with a summary of the measured improvements in the mechanical, electrical and thermal properties of the resulting hierarchical composites.
Ho KKC, Kolliopoulos A, Lamoriniere S, et al., 2010, Atmospheric Plasma Fluorination as Means to Improve the Mechanical Properties of Short Carbon Fibre Reinforced Poly (Vinylidene Fluoride), Composites Part A
The impact of fluorination of carbon fibres on the properties of short fibre reinforced polyvinylidene fluoride (PVDF) composites was studied. As received and continuously atmospheric plasma fluorinated (APF) carbon fibres were cut to an average fibre length of 2 mm. Short fibre composites (SFC) containing 5, 10 and 15 wt% carbon fibres were manufactured using a twin-screw mixer. Test specimens were produced by injection moulding. The mechanical properties of the SFC were studied using tensile and compression testing. As expected, the incorporation of short carbon fibres into PVDF led to an increase in strength and stiffness. The tensile strength and Young’s modulus of the SFC containing APF-treated carbon fibres increased by up to 17% and 190%, respectively. Furthermore, the compressive strength and modulus of the SFC containing APF-treated carbon fibres also increased by 19% and 35%, respectively. APF of carbon fibres results only in a marginal increase in the bulk matrix crystallinity of PVDF as determined by DSC. Scanning electron micrographs of fracture surfaces from tensile tested specimens exhibited a typical brittle failure mode with low fibre loading fraction. Despite the presence of up to 5% of voids and visible resin rich regions at fracture surface, SFC containing APF-treated fibres suggest better bonding at the fibre/matrix interface which led to the much enhanced mechanical properties.
Qian H, Bismarck A, Greenhalgh ES, et al., 2010, Carbon nanotube grafted carbon fibres: A study of wetting and fibre fragmentation, Composites Part A, Vol: 41, Pages: 1107-1114
Carbon nanotubes (CNTs) were grafted on IM7 carbon fibres using a chemical vapour deposition method.The overall grafting process resulted in a threefold increase of the BET surface area compared to the original primary carbon fibres (0.57 m2/g). At the same time, there was a degradation of fibre tensile strength by around 15% (depending on gauge length), due to the dissolution of iron catalyst into the carbon;the modulus was not significantly affected. The wetting behaviour between fibres and poly(methylmethacrylate) (PMMA) was directly quantified using contact angle measurements for drop-on-fibre systems and indicated good wettability. Single fibre fragmentation tests were conducted on hierarchical fibre/PMMA model composites, demonstrating a significant (26%) improvement of the apparent interfacial shear strength (IFSS) over the baseline composites. The result is associated with improved stress transfer between the carbon fibres and surrounding matrix, through the grafted CNT layer. The improved IFSS was found to correlate directly with a reduced contact angle between fibre and matrix.
Bloodworth V, Greenhalgh ES, Falzon B, et al., 2009, Observations on Local Strain Fields in CFRP Stiffened Element Tests Using Digital Image Correlation, 17th International Conference on Composite Materials
Shaffer M, Qian H, Menner A, et al., 2009, Hierarchical composites combining nanoscale reinforcements with conventional fibres, ICCM International Conferences on Composite Materials
Hierarchical composites introduce nanoscale fillers into the matrix of conventional fibre composites, in order to address critical failure modes. The effectiveness of growing carbon nanotubes onto primary fibres is reported at the single-fibre level. The success of an analogous, entirely renewable and biodegradable hierarchical composite system provides encouragement to scale-up.
Nguyen S, Greenhalgh ES, Iannucci L, 2009, Improved Aircraft Tire and Stone Models for Runway Debris Lofting Simulations, 50th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference
Iannucci L, Shaik Dawood M, Greenhalgh ES, et al., 2009, Delamination Control in Composite Beams Using Piezoelectric Actuators, 17th International Conference on Composite Materials
Nguyen SN, Greenhalgh ES, Iannucci L, et al., 2009, Improved models for runway debris lofting simulations, AERONAUTICAL JOURNAL, Vol: 113, Pages: 669-681, ISSN: 0001-9240
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- Citations: 5
Greenhalgh ES, 2009, Failure analysis and fractography of polymer composites, Cambridge, Publisher: Woodhead Publishing Limited, ISBN: 978 1 84569 217 9
Shirshova N, Greenhalgh ES, Shaffer M, et al., 2009, Structured Multifunctional Composites for Power Storage Devices, 17th International Conference on Composite Materials
Shaffer M, Qian H, Menner A, et al., 2009, Heirarchical Composites Combining Nanoscale Reinforcements with Conventional Fibres, 17th International Conference on Composite Materials
Bloodworth VM, Greenhalgh ES, Falzon B, et al., 2009, Observations on Local Strain Fields in CFRP Stiffened Element Tests Using Digital Image Correlation, London, 17th International Conference on Composite Materials, Publisher: IOM Communications Ltd
Shirshova N, Greenhalgh E, Shaffer M, et al., 2009, Structured multifunctional composites for power storage devices
We report the fabrication and performance of multifunctional composite materials for energy storage application. The electrochemical and mechanical properties of the obtained composites were systematically studied.
Shaffer M, Qian H, Menner A, et al., 2009, Hierarchical composites combining nanoscale reinforcements with conventional fibres
Hierarchical composites introduce nanoscale fillers into the matrix of conventional fibre composites, in order to address critical failure modes. The effectiveness of growing carbon nanotubes onto primary fibres is reported at the single-fibre level. The success of an analogous, entirely renewable and biodegradable hierarchical composite system provides encouragement to scale-up.
Iannucci L, Shaik Dawood MSI, Greenhalgh E, et al., 2009, Delamination control in composite beams using piezoelectric actuators
Composite materials have poor tolerance to impact loads. They initially absorb impact energy by creating fracture surfaces, such as matrix cracks and delaminations. In the present work, the possibilities of using of piezoelectric materials to control delamination in composite beams, subjected to low velocity impact are investigated.
Greenhalgh ES, 2009, Methodology and tools for failure analysis of polymer composites, FAILURE ANALYSIS AND FRACTOGRAPHY OF POLYMER COMPOSITES, Publisher: WOODHEAD PUBL LTD, Pages: 23-106
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- Citations: 2
Greenhalgh ES, 2009, Introduction to failure analysis and fractography of polymer composites, FAILURE ANALYSIS AND FRACTOGRAPHY OF POLYMER COMPOSITES, Publisher: WOODHEAD PUBL LTD, Pages: 1-22
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- Citations: 64
Greenhalgh ES, 2009, Case studies: failures due to material and manufacturing defects, FAILURE ANALYSIS AND FRACTOGRAPHY OF POLYMER COMPOSITES, Publisher: WOODHEAD PUBL LTD, Pages: 504-542
Greenhalgh ES, 2009, Case studies: failures due to overload and design deficiencies, FAILURE ANALYSIS AND FRACTOGRAPHY OF POLYMER COMPOSITES, Publisher: WOODHEAD PUBL LTD, Pages: 441-503
Greenhalgh ES, 2009, Fibre-dominated failures of polymer composites, FAILURE ANALYSIS AND FRACTOGRAPHY OF POLYMER COMPOSITES, Publisher: WOODHEAD PUBL LTD, Pages: 107-163
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- Citations: 11
Greenhalgh ES, 2009, Fatigue failures of polymer composites, FAILURE ANALYSIS AND FRACTOGRAPHY OF POLYMER COMPOSITES, Publisher: WOODHEAD PUBL LTD, Pages: 238-278
Greenhalgh ES, 2009, Case studies: failures of polymer composites due to in-service factors, FAILURE ANALYSIS AND FRACTOGRAPHY OF POLYMER COMPOSITES, Publisher: WOODHEAD PUBL LTD, Pages: 543-571
Greenhalgh ES, Rogers CE, Robinson P, 2009, Fractographic Observations on Delamination Growth and the Subsequent Migration Mechanisms Through the Laminate, Composites Science and Technology, Vol: 69, Pages: 2345-2351, ISSN: 0266-3538
This paper describes fractographic observations from the detailed examination of delamination fracture surfaces and offers an interpretation of the key growth mechanisms. Firstly, the relationship between toughness, delamination failure criteria and fracture morphology is presented and the influence of cusp formation and deformation on toughness is discussed. Observations regarding delaminations migrating through the lamina at multidirectional ply interfaces are then discussed. It is demonstrated how this migration process can be avoided in fracture toughness coupons and consequently the toughness of multidirectional ply interfaces can be characterised. The influence of migration on delamination growth from embedded defects in laminates under compression is presented, and these results are extended to demonstrate how migration influences damage growth in structures. The paper concludes by making recommendations for realistic modelling of migration, and suggests how it can be exploited in damage tolerant structural design.
Greenhalgh ES, 2009, Defects and damage and their role in the failure of polymer composites, FAILURE ANALYSIS AND FRACTOGRAPHY OF POLYMER COMPOSITES, Publisher: WOODHEAD PUBL LTD, Pages: 356-440
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- Citations: 13
Greenhalgh ES, 2009, Delamination-dominated failures in polymer composites, FAILURE ANALYSIS AND FRACTOGRAPHY OF POLYMER COMPOSITES, Publisher: WOODHEAD PUBL LTD, Pages: 164-237
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- Citations: 42
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