By 2020, the advanced composite market is predicted to be worth around £17 billion, with automotive the second largest growth sector (after wind energy) but still falling far short of its enormous growth potential; the high cost of production for advanced composite products is still a major obstacle to their wider exploitation. Government legislation on the reduction of emissions is an important driver across the transport sector and one way to achieve prescribed targets is through the substitution of relatively heavy metallic components with highly optimised light-weight advanced polymer composite parts. Consequently, there is an urgent need to address the economic viability of manufacturing with advanced polymer composites and realise their full weight and fuel saving potential. The proposed project aims to contribute to this overarching goal by introducing an ambitious low-cost route to manufacturing highly optimised advanced composite structures. The ability to produce 'steered-fibre laminates' containing non-linear fibre paths, creates a step change in the design space for advanced composite structures. The designer is able to reposition stress concentrations away from holes and inserts, improve a laminate's resistance to buckling and failure, and to enhance a laminate's dynamic response to vibrations. Ultimately this can lead to lighter, more optimised structures for use in the aerospace and automotive sectors, enhancing fuel efficiency and contributing to the broader goals of reduced cost and lower emissions across the transport sector. The aim of the proposed project is to implement and demonstrate a novel and disruptive manufacture process that can produce low-cost high-quality steered-fibre laminates, without use of expensive, capital intensive automated fibre placement machines (the current solution). The new process is best described as 2-D forming; in order to support this novel manufacture process, a custom-designed suite of computer aided design and manufacture software will be developed. Computational tools for digital manufacturing are essential if 2-D forming is to be successfully achieved without inducing severe wrinkling and buckling of the deforming biaxial sheet. Reducing cost will effectively bring fibre-steering technology to a broader range of applications, increasing its economic impact and bringing new manufacturing capabilities to a wider industrial base, with the UK leading the way in this important area of manufacturing.

Launch and recovery of small vehicles from a large vessel is a common operation in maritime sectors, such as launching and recovering unmanned underwater vehicles from a patrol of research vessel or launching and recovering lifeboats from offshore platforms or ships. Such operations are often performed in harsh sea conditions. The recent User Inspired Academic Challenge Workshop on Maritime Launch and Recovery, held in July 2014 and coordinated by BAE systems, identified various challenges associated with safe launch and recovery of off-board, surface and sub-surface assets from vessels while underway in severe sea conditions. One of them is the lack of an accurate and efficient modelling tool for predicting the hydrodynamic loads on and the motion of two floating bodies, such as vessels of different size which may be coupled by a non-rigid link, in close proximity in harsh seas. Such a tool may be employed to minimise the risk of collisions and unacceptable motions, and to facilitate early testing of new concepts and systems. It may also be used to estimate hydrodynamic loads during the deployment of a smaller vessel (for example, a lifeboat) and during recovery of a smaller vessel from the deck of a larger vessel. The difficulties associated with development of such tools lie in the following aspects: (1) the water waves in harsh sea states have to be simulated; (2) the motion of the small vehicle and change in its wetted surface during launch or recovery can be very large, possibly moving from totally dry in air to becoming entirely submerged; (3) the viscous effects may play an important role and cannot be ignored, and will affect the coupling between ocean waves and motion of the vehicles. Existing methods and tools available to the industry cannot deal with all of these issues together and typically require very high computational resources. This project will develop an accurate and efficient numerical model that can be applied routinely for the analysis of the motion and loadings of two bodies in close proximity with or without physical connection in high sea-states, which of course can be employed to analyse the launch and recovery process of a small vehicle from a large vessel and to calculate the hydrodynamics during the process. This will be achieved building upon the recent developed numerical methods and computer codes by the project partners and also the success of the past and ongoing collaborative work between them. In addition, the project will involve several industrial partners to ensure the delivery of the project and to promote impact.

This project is one of the small number of proposals selected by an industrial consortium in collaboration with EPSRC to go forward as full proposals to the EPSRC Launch and Recovery Co-Creation Initiative. It involves a collaboration between Exeter and Southampton Universities, Scripps Institution of Oceanography (USA), BAE Systems, MOD and OCEANWAVES (Germany). It is supported by a mentoring/dissemination group comprising: BAE Systems, MOD, SEA Ltd, Zenotech and ESI Group. The practical driver is to enable a wide range of wave limited maritime operations to be carried out safely at higher sea states than is presently feasible. Particularly important examples are launch and recovery operations from mother ships of small boats, manned and unmanned air vehicles, and submersibles. The research concerns the two coupled areas of: (a) predicting the actual shape of sea waves, termed Deterministic Sea Wave Prediction and the application of this to predicting calmer periods in otherwise large seas (Quiescent Period Prediction), and (b) a comprehensive investigation of the properties of such quiescent periods and the creation of a quiescence simulator. The research involves an integrated combination of challenging fundamental new theory, simulation, large scale data analysis and experimental testing. An applications oversight, designed to facilitate post project the optimum push through to higher technology readiness levels, is provided by the industrial mentoring panel. MOD and BAE Systems are also research partners. The research will provide the predicted wave environment information required by closely allied projects within this EPSRC Launch and Recovery Co-Creation Initiative which are aimed at (a) modelling the motion of small craft in the near wave/flow field of a parent vessel and (b) control of launch and recovery operations. An alternative application of the new science is in the optimal control of wave energy converters where large increases in performance per unit cost are possible (see the impact case).

The aim of this proposal is to transform the design and manufacture of structural systems by relieving the bottleneck caused by the current practice of restricting designs to a linear dynamic regime. Our ambition is to not only address the challenge of dealing with nonlinearity, but to unlock the huge potential which can be gained from exploiting its positive attributes. The outputs will be a suite of novel modelling and control techniques which can be used directly in the design processes for structural systems, which we will demonstrate on a series of industry based experimental demonstrators. These design tools will enable a transformation in the performance of engineering structural systems which are under rapidly increasing demands from technological, economic and environmental pressures. The performance of engineering structures and systems is governed by how well they behave in their operating environment. For a significant number of engineering sectors, such as wind power generation, automotive, medical robotics, aerospace and large civil infrastructure, dynamic effects dominate the operational regime. As a result, understanding structural dynamics is crucial for ensuring that we have safe, reliable and efficient structures. In fact, the related mathematical problems extend to other modelling problems encountered in other important research areas such as systems biology, physiological modelling and information technology. So what exactly is the problem we are seeking to address in this proposal? Typically, when the behaviour of an engineering system is linear, computer simulations can be used to make very accurate predictions of its dynamic behaviour. The concept of end-to-end simulation and virtual prototyping, verification and testing has become a key paradigm across many sectors. The problem with this simulation based approach is that it is built on implicit assumptions of repeatability and linearity. For example, many structural analysis methods are based on the concept of a frequency domain charaterisation, which assumes that response of the system can be characterised by linear superposition of the response to each frequency seperately. But, the response of nonlinear systems is known to display amplitude dependence, sensitivity to transient effects in the forcing, and potential bistability or multiplicity of outcome for the same input frequency. As a result, when the system is nonlinear (which is nearly always the case for a large number of important industrial problems) it is almost impossible to make dynamic predictions without introducing very limiting approximations and simplifications. For example, throughout recent history, there have been many examples of unwanted vibrations; Failure of the Tacoma Narrows bridge (1940); cable-deck coupled vibrations on the DongTing Lake Bridge (1999); human induced vibration on the Millennium Bridge (2000); NASA Helios failure (2003); Coupling between thrusters and natural frequencies of the flexible structure on the International Space Station (2009); Landing gear shimmy. In many cases, the complexity of modern designs has outstripped our ability to understand their dynamic behaviour in detail. Even with the benefit of high power computing, which has enabled engineers to carry out detailed simulations, interpreting results from these simulations is a fundamental bottleneck, and it would seem that our ability to match experimental results is not improving, due primarily to the combination of random and uncertain effects and the failure of the linear superposition approach. As a result a new type of structural dynamics, which fully embraces nonlinearity, is urgently needed to enable the most efficient design and manufacture of the next generation of engineering structures.

The aim of this proposal is to transform the design and manufacture of structural systems by relieving the bottleneck caused by the current practice of restricting designs to a linear dynamic regime. Our ambition is to not only address the challenge of dealing with nonlinearity, but to unlock the huge potential which can be gained from exploiting its positive attributes. The outputs will be a suite of novel modelling and control techniques which can be used directly in the design processes for structural systems, which we will demonstrate on a series of industry based experimental demonstrators. These design tools will enable a transformation in the performance of engineering structural systems which are under rapidly increasing demands from technological, economic and environmental pressures. The performance of engineering structures and systems is governed by how well they behave in their operating environment. For a significant number of engineering sectors, such as wind power generation, automotive, medical robotics, aerospace and large civil infrastructure, dynamic effects dominate the operational regime. As a result, understanding structural dynamics is crucial for ensuring that we have safe, reliable and efficient structures. In fact, the related mathematical problems extend to other modelling problems encountered in other important research areas such as systems biology, physiological modelling and information technology. So what exactly is the problem we are seeking to address in this proposal? Typically, when the behaviour of an engineering system is linear, computer simulations can be used to make very accurate predictions of its dynamic behaviour. The concept of end-to-end simulation and virtual prototyping, verification and testing has become a key paradigm across many sectors. The problem with this simulation based approach is that it is built on implicit assumptions of repeatability and linearity. For example, many structural analysis methods are based on the concept of a frequency domain charaterisation, which assumes that response of the system can be characterised by linear superposition of the response to each frequency seperately. But, the response of nonlinear systems is known to display amplitude dependence, sensitivity to transient effects in the forcing, and potential bistability or multiplicity of outcome for the same input frequency. As a result, when the system is nonlinear (which is nearly always the case for a large number of important industrial problems) it is almost impossible to make dynamic predictions without introducing very limiting approximations and simplifications. For example, throughout recent history, there have been many examples of unwanted vibrations; Failure of the Tacoma Narrows bridge (1940); cable-deck coupled vibrations on the DongTing Lake Bridge (1999); human induced vibration on the Millennium Bridge (2000); NASA Helios failure (2003); Coupling between thrusters and natural frequencies of the flexible structure on the International Space Station (2009); Landing gear shimmy. In many cases, the complexity of modern designs has outstripped our ability to understand their dynamic behaviour in detail. Even with the benefit of high power computing, which has enabled engineers to carry out detailed simulations, interpreting results from these simulations is a fundamental bottleneck, and it would seem that our ability to match experimental results is not improving, due primarily to the combination of random and uncertain effects and the failure of the linear superposition approach. As a result a new type of structural dynamics, which fully embraces nonlinearity, is urgently needed to enable the most efficient design and manufacture of the next generation of engineering structures.