CAMREG KEYSTONE PROJECTS
Theme 1: Multifunctional materials for energy applications
KP1 - Feasibility of luminescent coatings for optical measurement of strain. - Prof. Neil Robertson UoE Chemistry and Prof. Margaret Stack University of Strathclyde
This KP will test the feasibility of using luminescent coatings to assess mechanical strain with a view to their ultimate use as an in-situ non-destructive optical measuring sensor in moving components such as wind and tidal turbine blades. KP1 will build off the expertise in transparent polymeric or composite materials which also underpins in KP5 to develop deformable transparent hosts, likely based on polymers such as PDMS. The IMNS is in an excellent position to work with Chemistry to provide an integrated system for transducing the shape responsive fluorophores into an electronic signal. In addition, there is the opportunity to integrate in flexible microelectronic sensing technology for internal strain measurements using the wafer grinding technology for thinning down silicon IC technology.
KP2 – In-situ structural monitoring of composites for wind/tidal generation and storage. - Prof. Feargal Brennan University of Strathclyde & Prof. Conchur O'Bradaigh UoE Engineering
The design of composite components such as blades, for offshore renewable energy is dominated by fatigue loading of the main load-carrying stress centres. Monolithic (<100mm thick) glass and carbon fibre epoxy laminates must withstand 100+ million cycles of alternating loads in a moist air or seawater environment throughout their lifetime. Structural failure can be caused by delamination and collapse of the main load- carrying elements, initiated by fatigue cracks growing from matrix micro-cracks and moisture ingress.
This KP will characterise and optimise the dispersion of relatively inexpensive multi-walled CNTs in thick glass and carbon fibre laminates via well-dispersed CNT modified resins or the powder-epoxy process, will characterise the damage-sensing capabilities of the CNT networks and will develop methods of electrical resistivity measurement suitable for large composite structures and for light-weight pressure vessels.
The IMNS brings expertise to CAMREG through its test structure work on the high precision characterisation of resistive layers patterned during the manufacture of integrated circuits. This approach could lead to an opportunity to develop wireless communications in the composite for long-term monitoring of performance.
KP3 – Fatigue resisting composite materials. - Prof. Margaret Stack University of Strathclyde & Prof. Conchur O'Bradaigh UoE Engineering
The current level of erosion on offshore wind farms presents a significant performance reduction and long-term asset integrity risk. Understanding of the erosion mechanisms for current blade materials and surface coatings will assist in the development of new generation coatings tailored for exposure in such conditions.
The object of this KP is to develop an understanding of erosion and fatigue resistance in sea water conditions. For the loading requirements of tidal, wave and wind turbine energy conversion, erosion resistance in sea water conditions must be optimized. For wind turbines, meteorological maps will inform the testing based on the raindrop and hail impact patterns in the environment. Velocity, sediment loading and size are key variables in sea water conditions which will be investigated in such conditions for wave energy and tidal turbines. Scaled down test procedures will be used to assess material performance. Smart coatings and composites strategies will be generated based on the test conditions. A novel manufacturing strategy based on a toughened powder epoxy gradient will be developed to improve the erosion resistance properties without compromising the fatigue performance of the structures. The powder based composite structures will also exhibit lower viscosities, improving wetting and reducing porosity, as well as lower exotherms, reducing risk of thermal runaways in thick structures. Processing will also be more versatile as non-crosslinked parts could be bonded before curing, removing bonding steps and improving the cohesion of structures. The SHM strategies using CNTs from KP2 will also be trialled for monitoring of surface erosion. The erosion and fatigue testing will be carried out in a range of bespoke test rigs.
KP4 – Anti-biofouling and self-monitoring coatings. - Prof. Margaret Stack University of Strathclyde & Prof. Conchur O'Bradaigh UoE Engineering
Biofouling protecting coatings on immersed components are intended to prevent barnacles, oysters, tubeworms and other marine life from attaching to wave energy converter and tidal turbine surfaces. Such growth dramatically increases cyclic fatigue loadings and reduces the electricity generated by marine renewable energy devices.
Copper-based paints are usually used as antifouling technology. However, the toxicity of these paints, as well as toxic copper concentration build-up is a major concern, as were the previous organotin paint generation, which led to a worldwide ban in 2008. In this project, a new environmental friendly, self-sufficient and embedded system will be investigated.
The technology is based on electro chlorination, which have been used for enclosed systems but never to protect large exposed surfaces immersed in seawater. The chlorine species obtained via this method are quickly degraded (half-life of several hours, depending on UV intensity). A low concentration only (0.5ppm) is required for active protection on a targeted surface. This concentration is harmless for humans as it is the same chlorine concentration present in treated water for consumption purpose. The electrical output can be set according to the harshness of the environment. In the event of power failure and uncontrolled fouling the system can be powered up to remove any growth as the production of the antifouling elements are produced at the points of attachment of the growth, the rate of removal can be accelerated by the use of longer pulses and/or higher current. The system is based on a low voltage (6V or lower) for safety considerations, has a very low energy consumption, and can therefore be supplied by renewable energy (e.g. solar wind).