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Michael Sutcliffe - Composites and Textiles Research

Manufacturing processes for composites - Active
Although composite materials have become well-accepted in many applications, the widespread take-up and efficient use of these materials is limited by the problems associated with design and manufacture of composite components. One of the most important considerations facing a designer is understanding how the fabric behaves as it is draped over a mould. Experimental measurements of the deformation of the tows in a five-harness satin weave fabric were made to understand this process. A novel 'intermediate' drape model was developed to model in a relatively robust and rapid way the drape deformation. This model was used in a process optimisation procedure and applied to a case study of a composite helmet. Current work examines how wrinkling develops, particularly in forming of non-crimp fabrics. The project was undertaken with EPSRC funding and collaboration with the University of Nottingham and industrial companies by Shrikant Sharma and Alex Skordos. Ongoing work with Dassault Systemes, Hexcel and Jaguar Land Rover aims to develop benchmark forming tests, examining how wrinkling develops, particularly in forming of non-crimp fabrics.
Key publications:
Skordos AA, Monroy Aceves C, Sutcliffe MPF. A simplified rate dependent model of forming and wrinkling of pre-impregnated woven composites. Composites A (2007)
Sharma SB, Sutcliffe MPF. A simplified finite element model for draping of woven material. Composites A (2004)
Sharma SB, Sutcliffe MPF, Chang, SH. Characterisation of material properties for draping of dry woven composite material. Composites A (2003)

Waviness defects in composite structures - Active
Compressive failure
In the wind turbine and aerospace sectors recent innovations, including larger and more sophisticated structures, have driven the need for better understanding of failure of composite structures containing waviness defects. Real manufactured components contain a range of stress concentrators. The aim of this work is to understand and model how such defects affect the strength of the structure. The research has two main strands: (i) characterising realistic defects in industrial components and in controlled laboratory specimens, (ii) identifying mechanisms of compressive failure under fatigue loading and developing predictive models for failure at waviness defects, validated with experiments. Work has been co-funded by EPSRC and DSTL in collaboration with the University of Bristol and industrial partners.
Key publications:
Sutcliffe MPF, Lemanski SL, Scott AE. Measurement of fibre waviness in industrial composite components. Comp Sci Tech (2012)
Sutcliffe, MPF. Modelling the effect of size on compressive strength of fibre composites with random waviness. Comp Sci Tech (2013)
Lemanski SL, J Wang, Sutcliffe MPF, KD Potter, MR Wisnom. Modelling failure of composite specimens with defects under compression loading. Composites A (2013)

Lightweighting of trucks - Active
Composite decking
The aim of this project is to reduce CO2 emissions, as part of the Centre for Sustainable Road Freight, a consortium made up of the Universities of Cambridge and Heriot Watt and a number of industrial partners. A fleet study has been undertaken with some of the partners to identify the best candidate vehicles and operations to lightweight in order to reduce C02 emissions as well as fuel costs. Options for lightweighting have been explored, including composite sandwich decking and improved chassis design. The plan is to evaluate these design options in truck trials. The work has benefited from collaborations with Prof Warrior at the University of Nottingham and Prof Newaz at Wayne State University.
Key publications:
Galos J, Sutcliffe MPF, Newaz, G. Design, fabrication and testing of sandwich panel decking use in road freight trailers. Journal of Sandwich Structures and Materials, accepted (2016)
Galos J, Sutcliffe MPF, Newaz, G. Mechanical behaviour of phenolic coated Finnish birch plywood with simulated service damage. Wood Material Science & Engineering (2016)
Galos, J, Sutcliffe, M, Cebon, D, Piecyk, M, Greening, P. Reducing the Energy Consumption of Heavy Goods Vehicles through the Application of Lightweight Trailers: Fleet Case Studies. Transportation Research Part D (2015)

Tribology in composites manufacturing - Active
Microscopic contact of composite
In many manufacturing processes, tribology plays a key role in controlling deformation and material properties. While the mechanics of surface contact in metal-forming operations is well understood, this is not the case for composites. The project, funded by EPSRC and in collaboration with the University of Nottingham, Jaguar Land Rover and Granta Design, explores the fundamentals of friction in composites forming via microscopic experiments and modelling, and aims to link this with macroscopic testing. The aim is both to understand the mechanics but also to guide testing which can better characterise friction performance in real applications. Recent work has shown how the true area of contact between a dry fibre composite and a coated glass surface varies with the contact area and fabric properties. The contact area can be directly linked to the measured frictional resistance via a characteristic shear strength of the interface. The work has been undertaken by Olga Smerdova and Daniel Mulvihill.
Key publications:
Mulvihill DM, Sutcliffe MPF. Effect of tool surface topography on friction with carbon fibre tows for composite fabric forming. Composites A (2016)
Mulvihill DM, Smerdova A, Sutcliffe MPF. Friction of carbon fibre tows. Composites A(2016)
Smerdova O, Sutcliffe MPF. Multiscale tool-fabric contact observation and analysis for composite fabric forming. Composites A (2015)

Fibre microbuckling - Active
This project has explored the micromechanics of a microbuckling in composites in collaboration with Norman Fleck, other colleagues in Cambridge, and various industrial partners, with funding from DSTL and EPSRC. Experiments have explored the initiation and propagation of microbuckles in un-notched and notched components, with corresponding modelling work. An image analysis algorithm has been developed to quantify fibre waviness orientation and this has been applied to various specimens. The resulting measurements have been used to give statistical predictions of compressive strength. Current work looks at the generation of microbuckling during textile forming processes and the influence of friction on that.
Key publications:
Liu D, Fleck NA, Sutcliffe MPF. Compressive strength of fibre composites with random fibre waviness. J Mechanics and Physics Solids (2004)
Sutcliffe MPF, Fleck NA. 'Microbuckle propagation in fibre composites.' Acta Metallurgica et Materialia (1997)
Kratmann KK, Sutcliffe MPF, Lilleheden LT, Pyrz R, Thomsen OT, A novel image analysis procedure for measuring fibre misalignment in unidirectional fibre composites, Composites Science and Technology (2009)

Biomimetics and joining of composites - Complete
Biomimetic joint
The aim of this project, undertaken by Dr Avgoulas, was to use a biomimetic approach to improve understanding of joining between composites and metals. The work was undertaken in collaboration with Dowty Propellers. Joining of dissimilar materials is widespread in nature, with a wide range of strategies used to make these joints durable. A key method is to have a gradient of stiffness at the joint (for example in tendon to bone joints). This stategy was applied to joining of composite to steel, with the change in stiffness of the steel effected by a series of perforations. Modelling was used to optimise the stiffness gradient and experiments were used to confirm the effectiveness of the approach. A strength increase of up to 175% was measured using the perforation approach, compared with a monolithic steel adherend.
Key publications:
Avgoulas EI; Sutcliffe MPF. A review of natural joint systems and numerical investigation of bio-inspired GFRP-to-steel joints. Materials (2016)
Avgoulas EI, Sutcliffe MPF. Biomimetic-inspired CFRP to perforated steel joints. Composite Structures (2016)

Modelling of non-woven material - Complete
The project considered scientific modelling of the spun-bonded process to produce non-woven material. The emphasis of the project was on exploring development of non-uniformity and mechanical properties of the web, relating them to process conditions and micromechanical models. This project, which was funded by Fitesa and undertaken by Francesco Battacchio, involved a mixture of experimental and modelling work.
Key publications:
Battocchio F, Sutcliffe MPF, Teschner F. Fibre behaviour in the spunbonding process. Part I: Characterisation of air flow and fibre motion. Proc IMechE Part C (2015)
Battocchio F, Sutcliffe MPF, Teschner F. Fibre behaviour in the spunbonding process. Part II: Modelling fibre dynamics in turbulent flows. Proc IMechE Part C (2015)

Impact of textile composites - Complete
This project explored impact of two 3D woven CFRP composites, a layer-to-layer and an orthogonal weave, and 2D braided material. A range of experimental techniques were used to characterise failure, including c-scanning and vibration modal analysis. The effect of glass content in the 2D braided material was also examined. The project was undertaken by Guiseppe Zumpano and Carlos Monroy Aceves with EPSRC funding and in collaboration with the Universities of Nottingham and Cranfield and various other academic and industrial partners.
Key publications: Sutcliffe MPF, Monroy Aceves C, Stronge WJ, Choudhry RS, Scott AE. Moderate speed impact damage to 2D-braided glass-carbon composites. Composite Structures (2012)
McMillan AJ, Monroy Aceves C, Sutcliffe MPF. Moderate energy impact analysis combining phenomenological contact law with localised damage and integral equation method. Int J of Impact Engineering(2012)
Zumpano Z, Fox M, Stronge WJ, Sutcliffe MPF. Impact damage in hybrid braided twill composites. J Mat Sci 43 (2008)

Indentation of sandwich panels - Complete
Sandwich panels
Failure of sandwich honeycomb structures under indentation loading was considered. A failure criterion for Nomex honeycombs subjected to combined compressive and shear stresses was determined using biaxial tests. By combining this with a theoretical calculation of the stress distribution in the core due to indentation loading, found from a high-order sandwich beam theory (HOSBT), the indentation failure load of the sandwich beam due to core failure can be predicted. Short beam three-point bending tests are used to validate the theoretical predictions, using beams made with GFRP skins and Nomex cores with densities between 29 and 128 kg/m^3. Theoretical predictions of indentation failure load were in excellent agreement with measured values. Inclusion of shear stresses in the failure criterion significantly improved the predictions, correctly modelling the observed stronger behaviour of cores with a longitudinal ribbon direction. The project was undertaken as a PhD project by Achilles Petras.
Key publications:
Petras A, Sutcliffe, MPF. Indentation failure analysis of sandwich beams, Composite Structures 50, 311-318 (2000)
Petras A, Sutcliffe MPF. Failure mode maps for honeycomb sandwich panels, Composite Structures, 44, 237-252 (1999)
Petras A, Sutcliffe MPF. Indentation resistance of sandwich beams, Composite Structures 46, 413-424 (1999)

Optimisation of composite structures - Complete
Selection Chart
The aim of the project was to develop advanced process models and integrate these within a design/optimisation framework. Materials analysed included a 4x4 twill weave carbon/epoxy prepreg, a 5-harness satin weave carbon/epoxy prepreg and a 2x2 twill weave glass/polypropylene commingled fabric in dry form. Advanced draping models were developed including wrinkling and variability and these were incorporated into a process optimisation procedure. Results were validated by the University of Nottingham with practical forming experiments. A design selection methodology was developed to assist designers with the selection of a shortlist of composite structures designs from a large number of alternatives, taking into account conflicting design objectives or constraints (e.g. weight, performance and cost). The procedure is based on the generation of a database containing results from an exhaustive search of a wide range of possible solutions in the design space The project was undertaken with EPSRC funding and collaboration with the University of Nottingham and industrial companies by Carlos Monroy Aceves and Alex Skordos.
Key publications:
Skordos AA, Sutcliffe MPF. Stochastic simulation of woven composites forming. Comp Sci Tech (2008)
Monroy Aceves C, Sutcliffe MPF, Ashby MF, Skordos AA, Rodriguez Roman C. Design methodology for composite structures: A small low air-speed wind turbine blade case study. Materials and Design (2012)
Monroy Aceves C, Skordos AA, Sutcliffe, MPF. Design selection methodology for composite structures. Materials and Design (2008)

© 2016 Cambridge University Engineering Dept and Michael Sutcliffe.
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