The following outline some current areas of interest. Note that there
is a broader list of titles without descriptions at
the end of the page.
The following are offered as guidelines. I would be happy to supervise projects on related subjects.
- Influence of resin rich areas (RRA) on composite properties. The aerospace industry is considering out-of-autoclave processes to reduce the manufacturing costs for aircraft structures. However, when using a specific reinforcement the
compressibility of the fabric will determine the maximum achievable fibre volume fraction. In the absence of positive pressure on the laminate, there will inevitably be a lower fibre volume fraction in the composite. The project will manufacture composites
using a single batch of reinforcement with minimal pressure, one atmosphere of pressure in a vacuum bag and using positive pressure (compression press and/or autoclave). The mechanical properties (moduli and strengths) will be determined to ascertain whether the properties simply scale with fibre volume fraction or if there is a greater reduction in properties as the proportion of resin increases.
- Retention of silicone on moulded composite surfaces (with Alan Harper Composites
(AHC) - Saltash). It is becoming increasingly important to seek more cost effective
routes
to manufacture high fibre volume fraction composite components. Traditionally these use consumable materials placed over/around the pre-preg or dry reinforcement to enclose them in a vacuum environment
at high temperature with either just vacuum pressure or additional external pressure inside an autoclave. There is a strong economic and technical argument for the replacement of
these wasteful consumables with reusable silicone bags. AHC market
fiRST (Film Infusion Reusable Silicone Technology) low cost silicone membrane for multi-cycle use (~30-50 cycles for epoxy moulding or >500 cycles for polyester resin composites).
The aerospace industry appreciates the advantages of this
proposed change, although there is an understandable concern that a "silicone footprint" remains on the component after processing even though only fully cured silicone is in contact with the moulding.
The project will seek to determine the true silicone footprint (if any) on the surface of a moulding processed using the silicone bag. To quantify and qualify the research results,
the data should be compared to mouldings
made by other accepted traditional routes. AHC can supply small bespoke silicone test panel bags
and will attend briefing and progress
meetings.
Resource: Alan Harper, Consumables or reusable – a case for a more ecological and economic approach,
Proceedings of International Conference and Exhibition on Reinforced Plastics (ICERP 2011), FRP Institute, Mumbai, India, 2-4 March 2011.
- Poisson's ratio of reinforcement fibres. Recent results from a
doctoral project reported a axial Poisson's ratio of 0.45 for a jute fibre
reinforced epoxy resin composite. Using rule-of-mixtures to back-calculate
a Poisson's ratio for the fibre suggests the value should be around unity.
As the fibre are expected to be anisotropic, this number is valid in the
context of the Lemprière criteria. The project would attempt to
measure the axial Poisson's ratio of single fibres during tensile
testing. In AY2010/11, this
would involve macrophotography and image analysis (probably
ImageJ freeware). In AY2011/12, we
expect to have a tensile stage in the new electron micoscope.
- Compressibility of reinforcement and spacer media (complements the
In-Mould Gel Coating
(IMGC) project). ACMC is a partner in a Technology Strategy Board funded project to develop a novel process for applying the gel coat to composites in the mould.
In order to understand how the reinforcement and consumable materials perform in the RTM environment it would be useful to correlate gel-injection pressures/gel-coat thicknesses with mechanical compressibility test results.
- Z-direction adhesion tests on gel coats (complements the
IMGC project). To perform z-direction tensile tests on gel-coated surfaces and analyse failure modes (possibly including fast video recording of the tests to establish the fracture sequence).
- Drape and conformability of fabric reinforcements.
The terms drape and conformability are used interchangeably to describe the ease with which a fabric reinforcement may be fitted to a double curvature surface.
It would be more useful to make a distinction between the two terms, such that drape would be defined as the natural ability of the fabric to adapt to a 2D surface, and conformability would be defined as the extent to which a fabric
can be persuaded to adopt a sharp double curvature radius without wrinkling (external corners) or bridging (internal corners).
Various procedures have been proposed for the measurement of drape in textile fabrics, eg the form adopted when placed on a pipe or on a sphere. There
is a need for standardisation of such test techniques specific to high modulus fibre fabrics, which may not necessarily be the methods used for textile/apparel
fabrics. The proposed test technique would use both the pipe (single curvature) and sphere (double curvature) with the same circular piece of material. The position of the fabric edge would be monitored at 10 degree intervals around
the perimeter in each case. The extent of any coupling between the two modes of deformation would be indicated by plotting the two lines on the same graph of edge height against angle.
It may be appropriate to rotate the fabric on the pipe through 10 degree intervals and monitor the position at each increment.
Resources:
- Nigel Wright, An investigation into the drape of reinforcement fabrics, BEng project, 1989.
- Omar Bakkar, Drape of a reinforcement fabric, BEng Mechanical project, 1997.
- David Simpson, Forces required to form fabric materials into mould tool radii, BEng Composites project, May 2003.
- Conformability of in-mould gel coating materials (complements the
IMGC project). To analyse how the separator fabric used in the IMGC process conforms to single and double curvature surfaces
- Measuring surface quality of in-mould gel-coated composites.
It is likely that European harmonisation of Occupational Exposure Levels for
styrene will drastically reduce the permitted amount in the workplace and
Pollution Prevention legislation will require significant reductions at the
factory boundary. Most marine vessels have an external resin rich gel-coat which
provides resistance to environmental degradation as well as a cosmetic surface.
This is normally painted on sprayed onto open moulds and is likely to be the
primary source of styrene in the workplace, especially where the structural
laminate can be produced by a close-mould process. A novel techniques has been
proposed to permit injection of the structural laminate separately from the
injection of the gel-coat with a current research project funded by DTI
Technology Programme Zero Emission Enterprises theme.
The student project will consider the practical implementation of technologies
to quantify the roughness of the surfae produced.
Resources:
- Xavier Dubreuil, Investigation of gel coat surface quality by optical techniques, BEng Composites project, 2007.
- David Ireland, Assessment of the surface finish of gel-coated composites, BEng Composites project, 2007.
- Fractal analysis of gel coat surface finish (complements the
IMGC project). A visiting researcher developed a system for the measurement of surface finish of gel-coated components by the determination of the fractal dimension from a photographed image. This system is a potential
cost-effective alternative to the
Wave-Scan DOI used by the automotive industry.
Resources:
- Quentin Labrosse, Assessment of the surface
finish of gel coated composites, Stage Placement Report, June 2007 (and
dark box measurement apparatus).
- Interlaminar shear strength (with Carr Reinforcements
Limited - Stockport UK). The company is seeking an understanding of
the effect of changing fibre architecture on the interlaminar shear strength
(ILSS) of carbon fibre reinforced composites. They will provide
reinforcement fabrics for the manufacture and testing of laminates in
Plymouth. A parallel study might consider whether the ILSS of
laminates with odd numbers of layers (neutral axis within the central lamina) is greater than that of laminates with even numbers of layers
(neutral axis between lamina).
- Flow enhancement in glass
fibre reinforcement textiles (with Interglas Technologies - Sherborne).
Carr Reinforcements produced woven carbon fibre reinforcements with a novel
flow-enhancement technology for use in liquid composite moulding. In
his PhD thesis, Neil Pearce demonstrated that composites manufactured using
these fabrics has a sensible balance of processability and mechanical
properties. This project would undertake similar tests to ascertain
whether the technology is also applicable to glass fibre reinforcements.
Resources:
-
J Summerscales, FJ
Guild, NRL Pearce and PM Russell,
Voronoi cells, fractal dimensions and fibre composites, Journal of
Microscopy, February 2001, 201(2), 153-162.
Restricted:
Download 1.34 MB PDF
- Reconfigurable airport seating (with Zoeftig + Company). The beam system currently offers the simplest means of mounting multiple seats onto a single supporting structure. The combination of off the shelf components and straightforward engineering techniques results in a cost-effective solution for high volume, modular mass seating.
The main limitation of a beam is that no matter how versatile the components, their capacity to be configured will always be restricted by the fixed length of the beam and the limited number of possible combinations this will accommodate.
The key engineering challenge in developing a beamless system is that it will inevitably create localised points of high structural stress and weakness in a product that will be subject to constant and demanding use.
The product must be simple to manufacture and assemble. The use of innovative materials and manufacturing processes is encouraged. The potential for reconfiguration of the product throughout its lifetime is also a factor that must be considered.
This project is in association with Zoeftig + Co, one of the UK’s leading passenger seating manufacturers. You will have an opportunity to visit their factory in North Cornwall and have regular contact with their design and engineering department throughout the project.
- Correlation of the engineering and textile technology parameters for natural fibres.
Natural fibres are of uneven cross-section and may be hollow. The project would measure mechanical fibre properties using both engineering and textile parameters and attempt to establish whether there is a
correlation. Textile technologists measure strengths in N/tex (tex is g/km)
whilst engineers use N/m2 (Pa).
Resources:
- Chris Hoppins, An investigation into the correlation of the engineering and textile technology parameters for measurement of strength in
natural fibres, BSc MCT project, 2007 .
- Life Cycle Assessment of natural vs man-made fibres as reinforcements
The majority of composite materials have fibreglass as the material of construction. In the context of sustainability, it has been proposed that glass fibres might be substituted by
plant fibres, especially the bast fibres of flax, hemp and jute. There is a, perhaps unjustified, perception that the natural fibre option is more environmentally friendly.
The man-made fibres are produced in large industrial complexes with a requirement for high temperatures to melt the raw materials.
The natural fibres are grown over large areas and incur significant transport costs plus they require fertilisers, herbicides and pesticides which may pollute watercourses.
This project would undertake a comparative life cycle analysis of the two options to reinforce or otherwise refute the above perception.
Resources:
- John Summerscales,
Resources for Life Cycle Assessment of Natural Fibre Composites and Bio-Based Resins
- Tom Baker, Comparison of the environmental burden of natural vs glass fibres, BSc MCT project, 2007.
- Richard Fynan, Environmental impact of composite use in the surf industry, BSc Surf Science and Technology project, April 2004.
- MST326 coursework, 2006.
- Marine resources as raw materials for plastics
There is a current initiative to support the emergence of a
sustainable low carbon
seaweed industry in the South West. This might include using the
alginates and/or oils from algae to manufacture
bioplastics
(instead of the petrochemical oils used at present). The shellfish industry also produces considerable quantities of chitin from the exoskeletons of crustaceans (e.g.,
crabs, lobsters and shrimps). The project would consider whether materials
derived from these sources, individually or in combination, might be useable as commercial materials.
Resources:
- Ji-Sheng Yang, Ying-Jian Xie and Wen He, Research progress on chemical modification
of alginate: a review, Carbohydrate Polymers, 11 February 2011, 84(1), 33–39.
- M Dash, F Chiellini, RM Ottenbrite and E Chiellini, Chitosan - a versatile semi-synthetic polymer in biomedical applications, Progress in Polymer
Science, August 2011, 36(8), 981-1014.
- CKS Pillai, W Paul and CP Sharma, Chitin and chitosan polymers: chemistry, solubility and fiber formation, Progress in Polymer Science, July 2009, 34(7),
641-678.
- M Rinaudo, Chitin and chitosan: properties and applications, Progress in Polymer Science, July 2006, 31(7), 603-632.
- K Kurita, Controlled functionalization of the polysaccharide chitin, Progress in Polymer Science, November 2001, 26(9), 1921-1971.
- Use of diatoms as a biomimetic model for the design of perforated composite plates
In aircraft engine nacelles, there is normally a perforated composite plate as part of the sound-deadening system. The structural requirements necessitate continuous fibres but the presence of the holes makes fibre management difficult.
The book by FE Round, RM Crawford and DG Mann (The diatoms: biology & morphology of the genera, Cambridge University Press, Cambridge, 1990. ISBN 0-521-36318-7) has several examples of diatoms where the structure includes
multiple perforations. The project would use the electron microscope to attempt to establish how nature has solved the problem of combining such multiple stress concentrations with a highly efficient structure by seeking to determine the microstructure of the diatoms adjacent to the holes.
- Fly-through simulation of reinforcement fabrics.
The University has an active research theme in the manufacture of fibre reinforced plastic matrix composites. In the context of this problem we require a model for the surface
topology of a reinforcement fabric (these are typically plain weave, twill weave or satin weave). The classic approach is that by Peirce, although the model presented there is somewhat
simplistic. Recent work by Yurgartis has extended the modelling. It may be appropriate to use optical micrographs of actual fabric sections to build up a model of the real material.
The model would be required to:
- calculate the effective surface area of the fabric
- examine the contact length/area between layers
- examine the implications of lateral shifts between adjacent layers in respect of the closeness of stacking (nesting) of the layers
- examine the implications of rotational shifts between adjacent layers in respect of the closeness of stacking (nesting) of the layers
- produce a fly through simulation of the space between fabric layers
Resources:
- FT Peirce, The geometry of cloth structure, Journal of the Textile Institute, 1937, 28(.), T45-T97.
- FT Peirce, Geometrical principles applicable to the design of functional fabrics, Textile Research Journal, March 1947, 17(3), 123-134.
- SW Yurgartis and JP Maurer, Modelling of yarn shape and nesting in plain weave composites, Composites Science and Technology, 1993, 46(1), 39-50.
- G Dijon, Topology of some carbon fibre fabrics, Stage Placement Report, June 1997.
- Toby Jefferson, The surface topology and internal geometry of reinforcement fabrics for composites, BEng Manadon project, 1996.
- Amanda McIntyre, Topology of a fabric reinforcement, BEng Composites project, 1996.
- Kamaludin Tomiran, Topology of a fabric reinforcement for carbon fibre twill 2x2, BEng Mechanical project, 1998.
- Michael Beck, Modelling of woven fabrics for prediction of resin flow, BEng project, 1999.
- Measurement of the surface topology of a reinforcement fabric.
The surface topology of a woven reinforcement fabric is defined by the weave structure (typically plain, twill or satin weave) and the inherent crimp in the
individual tows due to the interlocking of the orthogonal fibres. An understanding of the topology is necessary for prediction of the
compressive properties of a stack of fabrics (the layers of a laminated composite) and for prediction of the wetted surface area and hence flow rates in
the resin transfer moulding process, and for estimation of the extent of resin rich areas in the finished composite. The loose structure does not easily permit the use of stylus methods for
the determination of topology. Optical methods of measurement tried to date have failed to describe the topology once the curvature presents anything other than small deviations from
the normal direction to the monitoring system. The project would examine possible routes to the determination of the fabric topology, including metal sputtering to increase the transverse strength of the
individual tows to permit stylus measurements and/or progressive sectioning of samples cast in resin in combination with quantitative optical microscopy. The project should produce a database of measured values and then proceed
towards a mathematical model.
Resources:
- Robin Siddall and James Letto, Composite materials research project: topology of reinforcement fabrics, Extended Engineering TECH 006 project, 1994/95.
- Toby Jefferson, The surface topology and internal geometry of reinforcement fabrics for composites, BEng Manadon project, 1996.
- Amanda McIntyre, Topology of a fabric reinforcement, BEng Composites project, 1996.
- Guillaume Dijon, Topology of some carbon fibre fabrics, Stage Placement Report, June 1997.
- Michael Beck, Modelling of woven fabrics for prediction of resin flow, BEng project, 1999.
- Energy-efficient manufacture of aerospace fibre-reinforced polymer composites (CoolClave).
The civil aerospace industry is increasing the proportion of fibre-reinforced polymer matrix composites in the structure of the airliner (current roll out at ~25%,
Boeing 787 Dreamliner and Airbus A350XWB targetting 50%). These large structural composites are manufactured by vacuum bag (pre-preg or infusion)
processes in which they are loaded into an autoclave for curing. This process heats all the pressurised air in the vessel in order to heat
the mould tool from the outside in order to heat the component contained within the tool. In an earlier KTP(TCS) project with GKN Aerospace (IOW), mould tools were made with integral heaters
adjacent to the tool surface with the outer surfaces convered by thermal insulation [1, 2]. This permits a significant reduction in energy consumption (and hence in greenhouse gas
emissions), especially as it could potentially permit pressurisation with ambient temperature air provided the thermal insulation were adequate to
minimise the effects of quenching on aerospace epoxy resins with a 180°C cure
temperature.
The Advanced Composites Manufacturing Centre has an advanced specification autoclave (400°C, 14 bar pressure) which would be ideal for exploratory experimental trials of this new
methodology and has extensive experience in pre-preg and infusion processes [3]. The Marine and Industrial Dynamic Analysis Research Group (MIDAS) has extensive experience of advanced control algorithms which would be essential to
the control of the process as proposed. At masters level, a student might be
expected to address one aspect of the following list (the integrated whole might
be a full doctoral research programme):
- investigate the use of heated tooling in combination with cool air pressurisation within the autoclave (for high-performance composites),
- develop combined infusion/autoclave technologies and appropriate process models,
- use a combination of experiment and numerical modelling to obtain a deeper understanding of the issues inherent in this approach,
- develop control methodologies appropriate to the new processing regime,
- quantify the potential for energy reduction during composite processing through the use of heated mould tools with cool air pressurisation,
- investigate the process-property relationships for composites under different consolidation conditions.
Resources:
- Iosif Progoulakis, Heated tooling for aerospace composite manufacture, MPhil thesis, University of Plymouth, May 2004.
Commercial-in-Confidence for five years.
- SM Grove, I Progoulakis, T Searle, J Summerscales and P Healey, Heated tooling for aerospace composites manufacture, SAMPE Journal, November/December 2005, 41(7), 36-45.
- J Summerscales and TJ Searle, Low pressure (vacuum infusion) techniques for moulding large composite structures, Proc IMechE Part L - Journal of Materials: Design and Applications, February
2005, L219(1), 45-58
- Dielectric monitoring of moisture levels in
structural materials. The structural performance of materials can be significantly affected by the moisture content of the material. Grove and Wang (ACMC) are
studying the effects of moisture in fibre-reinforced polymer matrix composites in the context of aerospace structures, while Goodhew et al (Sustainable
Building) are concerned with the effects of moisture on building materials. As the moisture content increases, the materials generally become more
“plastic” and consequently less suitable for structural application. The aerospace industry uses a “hot wet glass transition temperature” as a
key design criterion. The boating industry currently uses dielectric moisture meters in the survey of vessel
hulls. However, these instruments are notorious for each returning a very different value of moisture content because they use different electrode spacing and interrogation frequencies with
the hull exposed to the ambient relative humidity.
The project would work towards the development of an instrument capable of using:
(a) a variety of electrode spacings, (b) a variety of interrogation frequencies, and (c) dynamic measurement of changing moisture levels to characterise both
advanced composites and building materials. In addition to measuring the overall water content, it should be practical to identify any gradient in the moisture content and hence follow
transport phenomena (e.g. diffusion processes). Alternative techniques include impedance spectroscopy or free space microwave testing.
In addition to development of the dielectric instrument, the project would seek to develop well characterised materials for calibration purposes (fibreglass composites [1] and building materials [2]) and develop
their characteristic data sets for dielectric permittivity and loss factors against moisture content. This in turn could inform the development of a commercial instrument.
The practical investigation could be backed up by modelling (commercial
software includes the ElectroMagneticWorks (an Add-In for SolidWorks) [3] and Vector Fields Opera electromagnetic finite element
software [4] but the packages may not be available at Plymouth).
Resources:
- J Summerscales, Chapter 7: Dielectrometry, in J Summerscales (ed), Non-destructive Testing of Fibre-Reinforced Plastics Composites, Elsevier
Applied Science, London 1990.
- Matthew Greer, PhD, The effect of moisture content and composition on the compressive strength and rigidity of cob made from soil of the breccia pressures near Teignmouth, University of Plymouth,
1996.
- ElectroMagneticWorks
- Software for electromagnetics design
- Void transport in liquid composite moulding. During resin transfer moulding/resin infusion processes for the manufacture of composites, there is a lag between the leading edge of the resin
flow front and the point at which the voids behind the flow front clear. The study would consider the relative positions of resin/air and voided/void-free resin flow fronts.
- Rollerball pointer. During public lectures it is often necessary to point at specific details of a projected image to assist in audience comprehension.
The "snooker cue" has given way to extremely light-weight hand-held laser pointers. However, a slight movement of the hand produces a significant shift in the position of the dot on the
screen. If the pointer were to be mounted in a cradle and controlled by a computer/microprocessor it should be possible to have a stable point. The cradle would need to be calibrated to know (say) the top left and bottom right
corners to prevent the dot going off-screen. Further it must be possible to switch the pointer on/off as required (and possibly to switch between continuous and "flashing" modes).
- Sample carrier for lapping machine.This project arises from a Knowledge Transfer Partnership programme at
Lapmaster International
in Lee Mill. They have produced a Dual Face Oscillating lapping machine for the United States. The samples which are being machined need to be positioned on the oscillating lapping plates
by a carrier, but the available space is limited. The carrier must work in a wet abrasive environment and requires high stiffness. Subject to confirmation, the company will support the project.
- Analysis of the UK academic capability in composites and enhancement of teaching web pages There are a number of
UK universities with interests in fibre-reinforced
composite materials and structures. The project would undertake a critical analysis of the capabilities of the respective establishments and identify areas of weakness in the UK provision
which might become targets for future research projects. In the first instance, the capabilities might be mapped against the lecture titles for
module MATS324
and, where appropriate, identify enhancements to the above Teaching Support web pages. Any student considering this project would need to bring some degree of innovation to permit it to be aligned
with the project learning outcomes!
The above list is NOT exhaustive - some alternatives include:
- A framework for risk analysis in composites processing techniques
- Characterisation of reinforcement textiles
- Definition and measurement of the geometry
- measurement of the compression characteristics
- forces required to form fabrics into corners
- drape and wrinkling of fabric reinforcements
- accuracy of cut fabrics in net-shape fibre preforms
- novel three-dimensional textiles (with Carr Reinforcements Limited)
- Resin transfer moulding (RTM) of high fibre content composites
- preforming of reinforcement for net-shape components
- binder transport and final location during flow processes
- pressure profiles during flow processes
- Resin infusion under flexible tooling (RIFT)/resin film infusion (RFI)
- characterisation of thickness variations during the process
- characterisation of the flow media
- optimisation of boat hull manufacturing process
- study of relative positions of resin/air and voided/unvoided resin flow fronts
- Machining, bonding and repair of composites
- Joining thermoplastic composites
- Assessment of residual cure state of composites
- Non-destructive testing of fibre-reinforced composites
- Microstructural characterisation of woven composites
- composite microstructure-property relationships
- fabric geometry and topology using stylus profiling, or optical/laser and electron microscopy
- Natural fibres as reinforcements for composite materials
- Natural resins systems as the matrix for composite materials
- Smart materials and intelligent structures, including biomimetics
- embedded optical fibres in composite materials
NB: See Retrospective list of composite related projects
Return to MATS 324 home page
Created by John Summerscales on 11 May 2007 and updated on
12 October 2011 09:14. Terms and conditions. Errors and omissions. Corrections.