In recent years, the cost of energy produced by renewable supplies has steadily decreased. This factor, together with socio-economical reasons, has made renewable energies increasingly competitive, as confirmed by industry growth figures. Considering wind turbines (WTs), there are some interesting technical challenges associated with the drive to build larger, more durable rotors that produce more energy, in a cheaper, more cost efficient way. The rationale for moving towards larger rotors is that, with current designs, the power generated by WTs is theoretically proportional to the square of the blade length. Furthermore, taller WTs operate at higher altitudes and, on average, at greater wind speeds. Hence, in general, a single rotor can produce more energy than two rotors with half the area. However, larger blades are heavier, more expensive and increasingly prone to greater aerodynamic and inertial forces. In fact, it has been shown that they exhibit a cubic relationship between length and mass, meaning that material costs, inertial and self-weight effects grow faster than the energy output as the blade size increases. In addition, larger blades also have knock-on implications for the design of nacelle components. The wind-field through which the rotor sweeps varies both in time and space. Consequently, the force and torque distributions for the blades exhibit strong peaks at frequencies which are integer multiples of the rotor speed. Additional peaks are induced by lightly damped structural modes. The loads on the blades combine to produce unbalanced loads on the rotor which are transmitted to the hub, main bearing and other drive-train components. These unbalanced loads are a major contribution to the lifetime equivalent fatigue loads for some components which could cause premature structural failure. As the size of the blades increase, the unbalanced loads increase and the frequency of the spectral peaks decrease. Hence, they have an increasing impact as the size of the turbines become bigger. In this scenario, the demand for improvements in blade design is evident. The notion of increasingly mass efficient turbines, which are also able to harvest more energy, is immediately attractive. The viability of a novel adaptive blade concept for use with horizontal axis WTs is studied in this project. By suitably tailoring the elastic response of a blade to the aerodynamic pressure it could be possible to improve a turbine's annual energy production, whilst simultaneously alleviating structural loads. These improvements are obtained in a passive adaptive manner, by exploiting the capabilities that structural anisotropy and geometrically induced couplings provide. In particular, induced elastic twist could be used to vary the angle of attack of the blade sections according to power requirements, i.e. the elastic twist is tailored to change with wind speed proportionally to the bending load. The adaptive behaviour allows the blade geometry to follow the theoretically optimum shape for power generation closely (which varies as a function of the far field wind speed). This concept retains the load alleviation capability of previously proposed designs, whilst simultaneously enhancing energy production. Structurally, the adaptive behaviour is achieved by merging the bend-twist coupling capabilities of off-axis composite plies and of a swept blade planform. Potentially, an adaptive blade, controlled only by generator torque, could perform to power standards comparable to that of the current state-of-the-art-while greatly reducing complexity, cost and maintenance of wind turbines, by challenging the need for active pitch control systems.

Introducing porosity onto an aerofoil has been shown to have a significant influence on the boundary layer and provide significant reductions in its noise radiation. This proposal describes a multi-disciplinary research project aimed at understanding and exploiting the interactions between porous aerofoils and the boundary layers developing over them for the purpose of optimising noise reductions without compromising aerodynamic performance. The use of adaptive manufacturing technology will be investigated for providing the optimum porosity at different operating conditions.

Wind turbines and aircraft are well known to be noisy machines that limits their acceptability to people living close to their operation, such as wind farms and airports. This limitation of course has significant implications for the growth of the aerospace and renewable energy sectors, which is vital to the UK economy as a whole. Wind turbines and aircraft have common noise generation mechanisms, namely the interaction between the airfoil blades and wings with turbulent flow around it. Conventional airfoils have straight leading and trailing edges, which according to recent research by the authors of this proposal, is the noisiest geometrical configuration. Significant noise reductions in airfoil noise have been obtained by introducing serrations (or undulations) into the trailing edge and leading edge geometries. In separate studies, introducing riblets onto the airfoil surface (very fine grooves) have also been shown to produce significant reductions in drag. It is reasonable to assume that airfoil drag and its noise radiation are connected, although this has never been formally investigated. An investigation into this association is one of the objectives of this work. This project will seek to combine these three technologies into a single airfoil design for the simultaneous reduction of leading edge and trailing edge noise whilst preserving aerodynamic performance. This optimisation process will necessitate a fundamental understanding into their noise reductions mechanisms individually in order to ensure that their combined benefits are at least additive or may combine to be more effective than the sum of their benefits individually. The outcome of this work is a new generation of aerofoils with noise control at the heart of their design."

Breakthroughs in the development of new materials have historically been achieved largely by trial and error. My vision is that there is a new generation of advanced hierarchical materials that has never been addressed and can be achieved by design. This new generation draws inspiration both from recent experimental observations in existing materials and from biomimetics, and is made possible by recent advances in modelling and manufacturing. The main challenges faced by today's composites industry include (i) damage tolerance, (ii) manufacturability and (iii) sustainability. I argue that (i) hierarchical micro-structural designs for composites will be more damage tolerant and achieve over 100% increase in fracture toughness, (ii) that hierarchical discrete carbon-fibre systems will simultaneously address manufacturing and performance needs of the automotive industry, and (iii) that recycled carbon fibres will find a high-value market as semi-structural parts by also exploiting hierarchical architectures. My proposal is to define these hierarchical micro-structures by design and to then develop suitable manufacturing methods to realise them in practice.

The ACCIS CDT will continue to address the EPSRC's goal of Developing Leaders in the key area of advanced materials under the EPSRC priority area of Materials Technologies. The underpinning philosophy will be to train the next generation of pioneers in composites technologies at the interface between engineering, life sciences, physics and chemistry, noting that within ACCIS, composites are defined as synergistic combinations of materials which may exhibit multifunctional attributes. The need for the ACCIS CDT is now even more important strategically than was the case for the initial award. The utilisation of composites is growing at an unprecedented rate, as illustrated by the significant UK technological contribution to both the Boeing 787 and Airbus A350 with composite airframes, the need for rapid development of renewable energy (wind turbine blades) and the nascent interest in large scale production of automotive components by organisations such as McLaren and BMW. The need for lightweight, high performance, multifunctional materials is a key element in meeting the goals of a sustainable future. Thus, industrial usage is within a period of exponential rise. Furthermore, composite materials has been recognized as one of the key industries by which the UK can seek to rebalance the economy towards export driven high value manufacturing. We intend to build upon our strong existing platform by further increasing our international engagement and by attracting elite home and overseas students to widen the pool of highly skilled labour for UK industry, supported by a combination of industrial and scholarship funding.