Dr Simon A Hayes
PhD MEd BEng
Lecturer in Aerospace Engineering
Department of Materials Science and Engineering
Sir Robert Hadfield Building
Mappin Street, Sheffield, S1 3JD
Telephone: +44 (0) 114 222 5516
Fax: +44 (0) 114 222 5943
Simon Hayes was appointed in January 2000 as a lecturer in materials science associated with the faculty wide Aerospace Engineering degree programme. He joined Sheffield University in 1997 as a Research Associate after obtaining a PhD from Brunel University on optical fibre sensors for damage assessment in composite materials.
His research interests primarily concern the development of `SMART´ systems for health monitoring and mitigation in composite materials. He also has an interest in the nanomechanical testing of polymeric and other viscoelastic materials.
Health monitoring of composites is important for their widespread use in safety-critical applications, such as aerospace structures. One focus of the research is therefore the implementation of sensors which provide large area coverage without imposing excessive parasitic weight. The development of sensors based on a philosophy of low cost but high sensitivity is a focus of his research. This has led to the development of resistance-based and optical systems, which employ the reinforcing fibre as the sensing element, that are capable of damage location and quantification. He had also developed optical sensor systems using custom drawn chalcogenide glass fibres and is investigating the use of H-glass. A second focus of his research in smart materials is that of damage mitigation. Once damage is identified a response must be initiated, in this case some form of integral self-healing technology is desirable. One such system is the thermoplastic self-healing system developed by Dr Hayes and colleagues the employs a thermoplastic dissolved in a thermosetting resin system, which can be induced to heal when heated. He is also working on alternative methods of healing involving the development of supramolecular polymer systems.
A recent development related to the resistance-based self-sensing system is the use of reinforcing fibres as heating elements to cure the composite itself. To date, work has shown that direct application of an electric current to a carbon-fibre composite can induce cure, with similar energy requirements to an incandescent bulb, a substantial reduction in the energy requirements compared to conventional processing routes.
A further research interest is in the nanomechanical testing of viscoelastic materials. Nanoindentation, as a technique for determining the mechanical properties of small volumes of material, was primarily developed on hard elastic coatings. It is therefore difficult to apply the technique to viscoelastic materials. Dr Hayes has developed techniques that enable measurements using nanoindentation to be directly compared with those obtained from macromechanical tests on bulk polymers for both bulk polymers and polymer coatings.
Professional activities and recognition
- Member of the scientific committee for the conference Deformation and Fracture of Composites
- A practical structural health monitoring system for carbon fibre reinforced composite based on electrical resistance. Swait, TJ; Jones FR; Hayes, SA. Composites Science and Technology 72 (13) 1515-1523 (2012).
- Smart composite materials for self-sensing and self-healing. Swait, TJ; Rauf, A; Grainger, R; Bailey, PBS; Lafferty, AD; Fleet, EJ; Hand, RJ; Hayes, SA. Plastics Rubber and Composites 41 (4-5) 215-224 (2012).
- Characterisation of thermo-mechanical properties of MgO-Al2O3-SiO2 glass ceramic with different heat treatment temperatures. Shamsudin, Z; Hodzic, A; Soutis, C; Hand, RJ; Hayes, SA; Bond, IP. Journal of Materials Science 46 (17) 5822-5829 (2011)
- Calibrating a nanoindenter for very shallow depth indentation using equivalent contact radius. Tadjiev, DR; Hand, RJ; Hayes, SA. Philosophical Magazine 90 (13) 1819-1832 (2010).
- Chemical Monitoring of Composite Matrices by Evanescent Wave Spectroscopy. Bailey, PBS; Hayes, SA; Hand, RJ; et al. Emboding Intelligence in Structures and Integrated Systems 56 297-302 (2009
Peter Wilson is extending the optical self-sensing work to assess the properties of composites containing the sensor, and also to improve the sensitivity of the system.
Self-healing composites and polymers
Elliot Fleet is synthesising supramolecular polymer systems, with thermally reversible cross-links, in order to obtain improved mechanical properties while maintaining their healing ability.
Supachai Fakpiam is working on the fatigue of solid-state self-healing materials
Recent PhD graduates
Austin Lafferty studied the use of carbon nanotubes to reinforce polymer foams, while simultaneously altering their electrical properties.
Jack Howarth assessed the properties of composites produced from recycled carbon-fibres.
Richard Grainger developed thermally re-mendable thermosetting resin systems for aerospace composite production.