Imperial College London

Professor Emile S Greenhalgh

Faculty of EngineeringDepartment of Aeronautics

Professor of Composite Materials
 
 
 
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Contact

 

+44 (0)20 7594 5070e.greenhalgh CV

 
 
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Location

 

453AACE ExtensionSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

123 results found

Anthony DB, Qian H, Clancy AJ, Greenhalgh ES, Bismarck A, Shaffer MSPet al., 2017, Applying a potential difference to minimise damage to carbon fibres during carbon nanotube grafting by chemical vapour deposition, NANOTECHNOLOGY, Vol: 28, ISSN: 0957-4484

JOURNAL ARTICLE

Bismarck A, Blaker JJ, Anthony DB, Qian H, Maples HA, Robinson P, Shaffer MSP, Greenhalgh ESet al., 2016, Development of novel composites through fibre and interface/interphase modification, 37th Riso International Symposium on Materials Science - Understanding Performance of Composite Materials - Mechanisms Controlling Properties, Publisher: IOP PUBLISHING LTD, ISSN: 1757-8981

CONFERENCE PAPER

De Luca H, Anthony DB, Qian H, Greenhalgh ES, Bismarck A, Shaffer MSPet al., 2016, Non-damaging and scalable carbon nanotube synthesis on carbon fibres

© 2016, European Conference on Composite Materials, ECCM. All rights reserved.The growth of carbon nanotubes (CNTs) on carbon fibres (CFs) to produce a hierarchical fibre with two differing reinforcement length scales, in this instance nanometre and micrometre respectively, is considered a route to improve current state-of-the-art fibre reinforced composites [1]. The scalable production of carbon nanotube-grafted-carbon fibres (CNT-g-CFs) has been limited due to high temperatures, the use of flammable gases and the requirement of inert conditions for CNT synthesis, whist (ideally) maintaining underlying original substrate mechanical properties. Here, the continuous production of CNT-g-CF is demonstrated in an open chemical vapour deposition (CVD) reactor, crucially, whilst retaining the tensile properties of the carbon fibres. As synthesised CNTs have a diameter of sub 20 nm and length ca. 120 nm, which are predicted to provide ideal fibre reinforcement in composites by retaining optimal composite fibre volume fraction (60%), whilst improving interfacial bonding of the matrix and reinforcement [1, 2]. Mild processing techniques enable this modified CVD process to be fully compatible with industrial practices, and have the potential to generate large volumes of hierarchical CNT-g-CF material.

CONFERENCE PAPER

De Luca H, Anthony DB, Qian H, Greenhalgh ES, Bismarck A, Shaffer MSPet al., 2016, Non-damaging and scalable carbon nanotube synthesis on carbon fibres

© 2016, European Conference on Composite Materials, ECCM. All rights reserved. The growth of carbon nanotubes (CNTs) on carbon fibres (CFs) to produce a hierarchical fibre with two differing reinforcement length scales, in this instance nanometre and micrometre respectively, is considered a route to improve current state-of-the-art fibre reinforced composites [1]. The scalable production of carbon nanotube-grafted-carbon fibres (CNT-g-CFs) has been limited due to high temperatures, the use of flammable gases and the requirement of inert conditions for CNT synthesis, whist (ideally) maintaining underlying original substrate mechanical properties. Here, the continuous production of CNT-g-CF is demonstrated in an open chemical vapour deposition (CVD) reactor, crucially, whilst retaining the tensile properties of the carbon fibres. As synthesised CNTs have a diameter of sub 20 nm and length ca. 120 nm, which are predicted to provide ideal fibre reinforcement in composites by retaining optimal composite fibre volume fraction (60%), whilst improving interfacial bonding of the matrix and reinforcement [1, 2] . Mild processing techniques enable this modified CVD process to be fully compatible with industrial practices, and have the potential to generate large volumes of hierarchical CNT-g-CF material.

CONFERENCE PAPER

Herceg TM, Abidin MSZ, Greenhalgh ES, Shaffer MSP, Bismarck Aet al., 2016, Thermosetting hierarchical composites with high carbon nanotube loadings: En route to high performance, COMPOSITES SCIENCE AND TECHNOLOGY, Vol: 127, Pages: 134-141, ISSN: 0266-3538

JOURNAL ARTICLE

Herceg TM, Yoon S-H, Abidin MSZ, Greenhalgh ES, Bismarck A, Shaffer MSPet al., 2016, Thermosetting nanocomposites with high carbon nanotube loadings processed by a scalable powder based method, COMPOSITES SCIENCE AND TECHNOLOGY, Vol: 127, Pages: 62-70, ISSN: 0266-3538

JOURNAL ARTICLE

Javaid A, Ho KKC, Bismarck A, Steinke JHG, Shaffer MSP, Greenhalgh ESet al., 2016, Carbon fibre-reinforced poly(ethylene glycol) diglycidylether based multifunctional structural supercapacitor composites for electrical energy storage applications, JOURNAL OF COMPOSITE MATERIALS, Vol: 50, Pages: 2155-2163, ISSN: 0021-9983

JOURNAL ARTICLE

Katafiasz TJ, Iannucci L, Greenhalgh ES, 2016, Interlaminar and intralaminar properties of carbon spread tow and glass fibre hybrid composites for cost saving in the mass production of automotive components

© 2016, European Conference on Composite Materials, ECCM. All rights reserved.As the efficiency of the automotive engine shows signs of slow-down and the consumer is becoming more aware of the consequential ecological impact, the industry's need for lighter component materials grows more prominent. Carbon fibre composite materials have been subject to neglect within the consumer automotive industry due to their expense (whereas glass fibre materials have been used favourably over the last few decades [1]). Cost effective composite materials have therefore become an area of interest for the consumer automotive market, where year-on-year engine efficiency performance improvements and monetary savings are integral to company profits. The purpose of this research is to verify that the use of fibre hybrid composites, where two-stage pseudoductile responses can be found [2], [3], are a viable alternative to monolithic structures (which exhibit a more traditional one-stage brittle failure) in interlaminar and intralaminar failure modes. In recent years, there has been much work to understand the tensile response of fibre hybrid composites [2]-[5] but a lack of research in types of failure modes which are more likely within automotive components; these being delamination (interlaminar) and through-thickness tearing (intralaminar); the latter of which most likely occurs at stress concentrations at bolt holes and through-thickness discontinuities.

CONFERENCE PAPER

Katafiasz TJ, Iannucci L, Greenhalgh ES, 2016, Interlaminar and intralaminar properties of carbon spread tow and glass fibre hybrid composites for cost saving in the mass production of automotive components

© 2016, European Conference on Composite Materials, ECCM. All rights reserved. As the efficiency of the automotive engine shows signs of slow-down and the consumer is becoming more aware of the consequential ecological impact, the industry's need for lighter component materials grows more prominent. Carbon fibre composite materials have been subject to neglect within the consumer automotive industry due to their expense (whereas glass fibre materials have been used favourably over the last few decades [1] ). Cost effective composite materials have therefore become an area of interest for the consumer automotive market, where year-on-year engine efficiency performance improvements and monetary savings are integral to company profits. The purpose of this research is to verify that the use of fibre hybrid composites, where two-stage pseudoductile responses can be found [2], [3] , are a viable alternative to monolithic structures (which exhibit a more traditional one-stage brittle failure) in interlaminar and intralaminar failure modes. In recent years, there has been much work to understand the tensile response of fibre hybrid composites [2]-[5] but a lack of research in types of failure modes which are more likely within automotive components; these being delamination (interlaminar) and through-thickness tearing (intralaminar); the latter of which most likely occurs at stress concentrations at bolt holes and through-thickness discontinuities.

CONFERENCE PAPER

Mohsin MAA, Iannucci L, Greenhalgh E, 2016, Translaminar fracture toughness characterisation of carbon fibre reinforced thermoplastic composites

© 2016, European Conference on Composite Materials, ECCM. All rights reserved.The translaminar fracture toughness of carbon/thermoplastic T700/PA6.6 composite system was examined. The fracture toughness test was conducted using compact tension specimens of non-crimp fabric biaxial T700 carbon fibre reinforced PA6.6. The critical strain energies, GIc0, required to initiate and propagate the crack through the specimen were found to be between 72 - 81kJ/m2 and 77 - 95kJ/m2 respectively. Two compact tension (CT) specimen configurations were validated though finite element modelling (FEM) using LS-DYNA® prior to the test.

CONFERENCE PAPER

Mohsin MAA, Iannucci L, Greenhalgh E, 2016, Translaminar fracture toughness characterisation of carbon fibre reinforced thermoplastic composites

© 2016, European Conference on Composite Materials, ECCM. All rights reserved. The translaminar fracture toughness of carbon/thermoplastic T700/PA6.6 composite system was examined. The fracture toughness test was conducted using compact tension specimens of non-crimp fabric biaxial T700 carbon fibre reinforced PA6.6. The critical strain energies, G Ic 0 , required to initiate and propagate the crack through the specimen were found to be between 72 - 81kJ/m 2 and 77 - 95kJ/m 2 respectively. Two compact tension (CT) specimen configurations were validated though finite element modelling (FEM) using LS-DYNA® prior to the test.

CONFERENCE PAPER

Razavi S, Iannucci L, Greenhalgh E, 2016, Piezoelectric PVDF smart fibre for composite applications

© 2016, European Conference on Composite Materials, ECCM. All rights reserved.This research project aims to use the braiding manufacturing technique to produce a Polyvinylidene Fluoride (PVDF) 'smart fibre'. The smart fibre is a piezoelectric co-axial cable comprised of a conductive core electrode, the PVDF-braided yarns piezo element, and a conductive wire outer electrode. A custom in-house poling apparatus has been proposed to induce permanent piezoelectric properties into the PVDF yarns - using no inner core electrode - based on utilising the Simultaneous Stretching and Corona Poling (SSPC) technique. This method would be advantageous in terms of avoiding the challenges associated with the use of the in-line poling techniques, in the manufacturing process of the piezo cables with conventional hot-melt extrusion methods. A secondary method of poling the PVDF yarns was also investigated through incorporating a '0.4mm copper wire core electrode' with an 'eight-strand of 0.1mm copper wire outer electrode', and connecting them to a source of the high-voltage DC potential - in order to create a high electric field acting on the PVDF-braided structure inbetween. In addition, a series of tensile tests were carried out on the PVDF-braided conductive core wires including: Zylone1/Copper-coated, Vectran2/Copper-coated, and Polyamide 66 (PA66)/Silvercoated wires; where it was observed that the piezo element sensitivity to the external mechanical stimuli could be improved when using a stiffer core electrode material. A CAD and FE model of a 100 mm gauge-length of the smart fibre with associated inner and outer electrodes, were also developed using Solidworks and COMSOL Multiphysics 5.2 software, respectively.

CONFERENCE PAPER

Razavi S, Iannucci L, Greenhalgh E, 2016, Piezoelectric PVDF smart fibre for composite applications

© 2016, European Conference on Composite Materials, ECCM. All rights reserved. This research project aims to use the braiding manufacturing technique to produce a Polyvinylidene Fluoride (PVDF) 'smart fibre'. The smart fibre is a piezoelectric co-axial cable comprised of a conductive core electrode, the PVDF-braided yarns piezo element, and a conductive wire outer electrode. A custom in-house poling apparatus has been proposed to induce permanent piezoelectric properties into the PVDF yarns - using no inner core electrode - based on utilising the Simultaneous Stretching and Corona Poling (SSPC) technique. This method would be advantageous in terms of avoiding the challenges associated with the use of the in-line poling techniques, in the manufacturing process of the piezo cables with conventional hot-melt extrusion methods. A secondary method of poling the PVDF yarns was also investigated through incorporating a '0.4mm copper wire core electrode' with an 'eight-strand of 0.1mm copper wire outer electrode', and connecting them to a source of the high-voltage DC potential - in order to create a high electric field acting on the PVDF-braided structure inbetween. In addition, a series of tensile tests were carried out on the PVDF-braided conductive core wires including: Zylone 1 /Copper-coated, Vectran 2 /Copper-coated, and Polyamide 66 (PA66)/Silvercoated wires; where it was observed that the piezo element sensitivity to the external mechanical stimuli could be improved when using a stiffer core electrode material. A CAD and FE model of a 100 mm gauge-length of the smart fibre with associated inner and outer electrodes, were also developed using Solidworks and COMSOL Multiphysics 5.2 software, respectively.

CONFERENCE PAPER

Syed Abdullah SIB, Iannucci L, Greenhalgh ES, 2016, An experimental study of the mode i interlaminar fracture toughness of vectran/epoxy composites

© 2016, European Conference on Composite Materials, ECCM. All rights reserved.Aircraft structures are susceptible to delamination from forward facing High Velocity Impact (HVI) in all regimes during service. Advanced composite fibres, such as Vectran could improve HVI performance on aircraft structures, hence creating a safer air travel environment. Vectran fibre are considerably tougher compared to Carbon Fibre Reinforced Plastic (CFRP). In this study, the interlaminar fracture toughness GIC of Vectran/Epoxy laminates is investigated from a Double Cantilever Beam (DCB) test, and compared to monolithic CFRP (T800s/M21). It was found that the interlaminar fracture toughness for Vectran/Epoxy material is significantly higher than that of T800s/M21 (GIC,Vectran ≈ 1.5 kJ/m2; GIC,T800s ≈ 0.246 kJ/m2).

CONFERENCE PAPER

Syed Abdullah SIB, Iannucci L, Greenhalgh ES, 2016, An experimental study of the mode i interlaminar fracture toughness of vectran/epoxy composites

© 2016, European Conference on Composite Materials, ECCM. All rights reserved. Aircraft structures are susceptible to delamination from forward facing High Velocity Impact (HVI) in all regimes during service. Advanced composite fibres, such as Vectran could improve HVI performance on aircraft structures, hence creating a safer air travel environment. Vectran fibre are considerably tougher compared to Carbon Fibre Reinforced Plastic (CFRP). In this study, the interlaminar fracture toughness G IC of Vectran/Epoxy laminates is investigated from a Double Cantilever Beam (DCB) test, and compared to monolithic CFRP (T800s/M21). It was found that the interlaminar fracture toughness for Vectran/Epoxy material is significantly higher than that of T800s/M21 (G IC,Vectran ≈ 1.5 kJ/m 2 ; G IC,T800s ≈ 0.246 kJ/m 2 ).

CONFERENCE PAPER

Greenhalgh ES, Ankersen J, Asp LE, Bismarck A, Fontana QPV, Houlle M, Kalinka G, Kucernak A, Mistry M, Nguyen S, Qian H, Shaffer MSP, Shirshova N, Steinke JHG, Wienrich Met al., 2015, Mechanical, electrical and microstructural characterisation of multifunctional structural power composites, JOURNAL OF COMPOSITE MATERIALS, Vol: 49, Pages: 1823-1834, ISSN: 0021-9983

JOURNAL ARTICLE

Jollivet T, Greenhalgh E, 2015, Fractography, a powerful tool for identifying and understanding fatigue in composite materials, 6th International Conference on Fatigue Design (Fatigue Design), Publisher: ELSEVIER SCIENCE BV, Pages: 171-178, ISSN: 1877-7058

CONFERENCE PAPER

Qian H, Nguyen S, Anthony DB, Singh A, Xu S, Greenhalgh E, Bismarck A, Shaffer Met al., 2015, Stiff monolithic aerogel matrices for structural fibre composites, 20th International Conference on Composite Materials, Publisher: iccm-central.org

Resorcinol-formaldehyde based aerogel precursors were infused into structural carbon fibreweaves, then gelled and carbonised to generate a continuous monolithic matrix network. Thishierarchical carbon preform was subsequently infused with polymeric resins, both multifunctional andstructural, to produce dense composites. The resulting hierarchical composites have a nanoscalereinforcement in the matrix at up to an order of magnitude higher loadings than typically available byother techniques. Compression, tension, ±45° shear and short beam tests demonstrate the potential ofsuch matrix systems to address matrix dominated failures. However, for the best structuralperformance it will be necessary to re-optimise the fibre-matrix interface, which is degraded by thecurrent processing regime.

CONFERENCE PAPER

Tsampas SA, Greenhalgh ES, 2015, Failure investigation of polymeric composite components, JEC Composites Magazine, Vol: 52, Pages: 46-49, ISSN: 1639-965X

© 2014 Aker Solutions. Fractographic analysis, i.e. the examination and interpretation of fracture surfaces, provides an insight into the causes and location of failure. Previously considered as a "black art", specialists now relate fracture morphologies to failure mechanisms with confidence and provide information about the failure sequence and source of failure initiation. This technique gives great feedback and can allow better design for next-generation parts.

JOURNAL ARTICLE

Tsampas SA, Greenhalgh ES, Ankersen J, Curtis PTet al., 2015, Compressive failure of hybrid multidirectional fibre-reinforced composites, COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING, Vol: 71, Pages: 40-58, ISSN: 1359-835X

JOURNAL ARTICLE

Asp LE, Greenhalgh ES, 2014, Structural power composites, COMPOSITES SCIENCE AND TECHNOLOGY, Vol: 101, Pages: 41-61, ISSN: 0266-3538

JOURNAL ARTICLE

Canturri C, Greenhalgh ES, Pinho ST, 2014, The relationship between mixed-mode II/III delamination and delamination migration in composite laminates, COMPOSITES SCIENCE AND TECHNOLOGY, Vol: 105, Pages: 102-109, ISSN: 0266-3538

JOURNAL ARTICLE

Greenhalgh ES, Canturri C, Pinho ST, 2014, A methodology for realistic delamination growth prediction based on fractographic observations, Publisher: DEStech Publications

Delamination has dominated aerostructures research for several decades but the development of robust delamination growth models is yet to be achieved. The complexity of the delamination processes from even relatively simple defects (such as from an embedded disbond) means predicting progressive damage propagation beyond initiation is very difficult. Consequently, this has hindered damage tolerant design, promoting an over-reliance on 'make and test' rather than predictive models to support certification of composite aerostructures. Recent research has highlighted that two underpinning phenomena dictate delamination processes; (i) directionality and (ii) migration. The former is the observation that delaminations tend to preferentially grow parallel to the fibers whilst the latter is a consequence of when conditions force delaminations to growth oblique to the fibers. In essence, delaminations have preferential growth directions, and will propagate through the thickness of a laminate to reach ply interfaces that are conducive to such preferential growth. The work reported here describes development of a modeling methodology based on the observed delamination phenomena. The paper first outlines detailed observations stemming from a study into delamination growth from embedded defects. Based on these, the work then utilized a bespoke width tapered end-loaded split (WTELS) test method, which provided high fidelity data from which to validate model predictions. For fractographic observations the mode II/III mixity was characterized by the relative in-plane orientation of the cusps with respect to the fibers. The relationship between mode II/III mixity (as determined using a transposed VCC formulation) and delamination migration was deduced. It was demonstrated that when a critical proportion of mode III was exceeded, delamination migration ensued. The paper concludes by presenting the implications of these observations and a revised model formulation for delamination mod

CONFERENCE PAPER

Greenhalgh ES, Canturri C, Pinho ST, 2014, A methodology for realistic delamination growth prediction based on fractographic observations

Delamination has dominated aerostructures research for several decades but the development of robust delamination growth models is yet to be achieved. The complexity of the delamination processes from even relatively simple defects (such as from an embedded disbond) means predicting progressive damage propagation beyond initiation is very difficult. Consequently, this has hindered damage tolerant design, promoting an over-reliance on 'make and test' rather than predictive models to support certification of composite aerostructures. Recent research has highlighted that two underpinning phenomena dictate delamination processes; (i) directionality and (ii) migration. The former is the observation that delaminations tend to preferentially grow parallel to the fibers whilst the latter is a consequence of when conditions force delaminations to growth oblique to the fibers. In essence, delaminations have preferential growth directions, and will propagate through the thickness of a laminate to reach ply interfaces that are conducive to such preferential growth. The work reported here describes development of a modeling methodology based on the observed delamination phenomena. The paper first outlines detailed observations stemming from a study into delamination growth from embedded defects. Based on these, the work then utilized a bespoke width tapered end-loaded split (WTELS) test method, which provided high fidelity data from which to validate model predictions. For fractographic observations the mode II/III mixity was characterized by the relative in-plane orientation of the cusps with respect to the fibers. The relationship between mode II/III mixity (as determined using a transposed VCC formulation) and delamination migration was deduced. It was demonstrated that when a critical proportion of mode III was exceeded, delamination migration ensued. The paper concludes by presenting the implications of these observations and a revised model formulation for delamination mod

CONFERENCE PAPER

Herceg TM, Zainol Abidin MS, Greenhalgh ES, Shaffer MSP, Bismarck Aet al., 2014, A powder based processing route to produce nano and hierarchical composites with high nanofiller loadings

A route to manufacture hierarchical composites (HCs) based on wet powder impregnation was adapted to accommodate thermosetting matrices. The resulting carbon fibre prepregs contained as much as 13.6 vol% carbon nanotubes (CNTs) in the matrix and were consolidated into laminates with 50 to 55% fibre volume fraction and 6.1% CNTs by total volume. Microscopic characterisation revealed that matrix homogeneity and laminate microstructure were affected by the powder particle size and degree of tow overlap during drum winding. The interlaminar shear strength was strongly affected by the quality of the material, requiring optimization of the processing parameters to improve the laminate quality.

CONFERENCE PAPER

Herceg TM, Zainol Abidin MS, Shaffer MSP, Greenhalgh ES, Bismarck Aet al., 2014, Hierarchical or fibre reinforced nano-composites: An opportunity to improve matrix dominated composite properties

We will briefly review the progress made in the development and processing of hierarchical, also called nanoenergineered or nanoreinforced, composites. Particular attention will be paid to the various methods to create hierarchical composites, i.e. reinforcing a nanocomposite further with conventional fibres or by attaching a nanoreinforcement to the surfaces of conventional reinforcing fibres and so avoiding all issues related to processing nanocomposites containing high aspect ratio nanoparticles. We will also review the properties of hierarchical composites and provide perspectives for future progress, which may require looking back at fibre wet impregnation by powder slurry processes.

CONFERENCE PAPER

Javaid A, Ho KKC, Bismarck A, Shaffer MSP, Steinke JHG, Greenhalgh ESet al., 2014, Multifunctional structural supercapacitors for electrical energy storage applications, JOURNAL OF COMPOSITE MATERIALS, Vol: 48, Pages: 1409-1416, ISSN: 0021-9983

JOURNAL ARTICLE

Nguyen SN, Greenhalgh ES, Graham JMR, Francis A, Olsson Ret al., 2014, Runway debris impact threat maps for transport aircraft, AERONAUTICAL JOURNAL, Vol: 118, Pages: 229-266, ISSN: 0001-9240

JOURNAL ARTICLE

Shirshova N, Bismarck A, Greenhalgh ES, Johansson P, Kalinka G, Marczewski MJ, Shaffer MSP, Wienrich Met al., 2014, Composition as a Means To Control Morphology and Properties of Epoxy Based Dual-Phase Structural Electrolytes, JOURNAL OF PHYSICAL CHEMISTRY C, Vol: 118, Pages: 28377-28387, ISSN: 1932-7447

JOURNAL ARTICLE

Shirshova N, Qian H, Houlle M, Steinke JHG, Kucernak ARJ, Fontana QPV, Greenhalgh ES, Bismarck A, Shaffer MSPet al., 2014, Multifunctional structural energy storage composite supercapacitors, FARADAY DISCUSSIONS, Vol: 172, Pages: 81-103, ISSN: 1359-6640

JOURNAL ARTICLE

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