This research addresses the important but as yet unresolved problem of providing a design methodology for sensor configuration for control and fault tolerance based on specific system reliability requirements. The primary focus is that of optimised sensor selection for efficient robustness properties of the system, assuming a consistent controller design, with relation to faults prior to system reconfiguration (i.e. a form of passive fault tolerance attempting to reduce complexity at the basic level). The proposed framework will be evaluated within a reconfigurable scheme for further system robustification. In particular the proposed research concentrates upon practical engineering applications that are dynamically complex, electro-mechanical in nature typified by the kinds of systems in aerospace, automotive and railway. Demonstration of the developed methodologies is envisaged via an experimental test rig.

This proposal is concerned with the renewal of the Salford IMRC which was initially established in January 2002. This proposal will extent the life of the Salford Centre for Research and Innovation (SCRI) in the built and human environment, until 2011 and further increase the impact that the centre has created in the first five years of its lifecycle. The rolling research agenda and evolving vision of the Centre has been very well received by the industrial and academic circles, as it has been made explicit by the international assessment panels and this renewal aims to firmly establish the world class status of the centre and increase the performance of UK Plc. The centre brings together significant expertise from three research institutes within the university of Salford and aims to continue its collaboration with more that 60 partners in the industrial and academic communities internationally.

Metamaterials are artificial materials with characteristics beyond those found in nature that unlock routes to material and device functionalities not available using conventional approaches. Their electromagnetic, acoustic or mechanical behaviour is not simply dictated by averaging out the properties of their constituent elements, but emerge from the precise control of geometry, arrangement, alignment, material composition, shape, size and density of their constituent elements. In terms of applications, metamaterials have phenomenal potential, in important areas, from energy to ICT, defence & security, aerospace, and healthcare. Numerous market research studies predict very significant growth over the next decade, for example, by 2030 the metamaterial device market is expected to reach a value of over $10bn (Lux Research 2019). The 'Metamaterials' topic is inherently interdisciplinary, spanning advanced materials (plasmonics, active materials, RF, high index contrast, 2D materials, phase change materials, transparent conductive oxides, soft materials), theoretical physics, quantum physics, chemistry, biology, engineering (mechanical and electrical), acoustics, computer sciences (e.g. artificial intelligence, high performance computing), and robotics. Historically, the UK has been a global leader in the field, with its roots in the work of radar engineers in the 2nd World War, and being reinvigorated by the research of some of our most eminent academics, including Professor Sir John Pendry. However today, it risks falling behind the curve. As a specific example, the Chinese government has funded the development of the world's first large-scale metamaterial fabrication facility, which has capacity to produce 100,000 m2 of metamaterial plates annually, with projects relating to aerospace, communication, satellite and military applications. The breadth of metamaterial research challenges is huge, from theory, fabrication, experiment, and requiring expertise in large-scale manufacturing and field testing for successful exploitation. We believe that the isolation of research groups and lack of platforms to exchange and develop ideas currently inhibits the UK's access to the interdisciplinary potential existing within our universities, industries, and governmental agencies. It is of the utmost importance to develop interactions and mobility between these communities, to enable knowledge transfer, innovation, and a greater understanding of the barriers and opportunities. The intervention that this Network will provide will ensure that the UK does not lag our international competitors. Via the Network's Special Interest Groups, Forums, National Symposia and other community-strengthening strategies, the enhanced collaboration will help resolve key interdisciplinary challenges and foster the required talent pipeline across academia and industry. As a result we will see an increase in research power for the metamaterials theme, and therefore reaping the impact opportunities of this area for UK economy and society. The Network's extensive promotion of the benefits of metamaterials technology (e.g., case studies, white papers etc), facilitation of access to metamaterial experts and facilities (through the online database) and closer interactions with end-users at appropriate events (e.g. industry-academia workshops) will help grow external investment in metamaterials research. Ultimately the Network will provide the stimulation of a discovery-innovation-enterprise cycle to meet desired outcomes for prosperity and consequentially, society, defence, and security.

Structural Health Monitoring (SHM) has the potential to radically alter the way in which safety-critical structures, such as aircraft fuselages, ships' hulls and power plant, are designed, operated and maintained over their lifetimes. This is an active area of research, involving a range of disciplines and approaches. One of the popular ideas for plate-like structures is to use guided waves (Lamb waves) which propagate in the plates and so can cover large areas. Previous research has shown the potential for this idea, important progress being made for example in the areas of transduction and communication, but the ideal of producing a map of defect locations for a large area using a small number of transducers remains a challenge. The goal of this proposed work is to demonstrate that an SHM system based on the transmission of low frequency ultrasonic guided waves between elements in a sparse distributed array of permanently attached sensors can be used to provide reliable damage detection and location capability throughout a structure. The key new features here are: (a) the use of a new intelligent subtraction algorithm, in which recorded images are subtracted from a reference (undamaged) image, so dramatically increasing the imaging capability from a given number of sensors; (b) the use of low frequency Lamb waves, with optimisation of mode and frequency, to image structures which include some realistic complexity, such as stiffeners. The achievement of these goals will be a major step forward in this topic and will provide a much-needed boost in confidence in the practical use of Lamb waves for SHM. In order to keep a strong focus on achieving industrially useful progress, the final output of the project will be the construction of optimised SHM demonstrator systems on two relevant structures provided by the collaborators.

Ever since the jet age began in the 1950s, governments, scientists, and engineers have been acutely aware of the health effects created by aircraft noise--the prolonged exposure of which is highly damaging to human health. Increased noise pollution, for example, has been linked to cognitive impairment and behavioural issues in children, sleep disturbance (and consequent health issues therefrom) as well as the obvious hearing damage caused by the repeated intrusion of high levels of noise. The World Health Organization estimates that 1-million healthy life years are lost in Europe due to noise; this is mainly by cardiovascular disease via the persistent increase in stress level-with aviation noise being the largest contributor here. Moreover, the Aviation Environment Federation found that these issues place a £540M/year burden on UK government expenditure. While there has been tremendous progress in understanding aircraft noise, the doubling of flights in the past 20 years to a staggering 40 million (in the pre-Covid year 2019) has heightened the need for research into the physics of jet noise to uncover new reduced-order turbulence models. This proposal develops a novel mathematical model for jet flow turbulence using asymptotic analysis. The re-constructed turbulence structure will be used within a numerical code for fast noise prediction of a high-speed axisymmetric jet flow. Fundamentally, a jet flow breaking down into turbulence creates pressure fluctuations that propagate away as sound. In 1952, Lighthill showed that the Navier-Stokes equations can be exactly re-arranged into a form where a wave operator acting on the pressure fluctuation, is equal to the double-divergence of the jet's Reynolds stress. When the auto-covariance of the Reynolds stress was assumed to be known for a fluid at rest, scaling properties of the acoustic spectrum were obtained such as the celebrated 8th power law. The generalized acoustic analogy formulated by Goldstein in 2003 advanced this idea by dividing the fluid mechanical variables into a steady base flow and its perturbation. The acoustic spectrum per unit volume is a tensor product of a propagator and the auto-covariance of the purely fluctuating Reynolds stress tensor. The propagator can be calculated by determining the Green's function of the Linearized Euler operator for an appropriate jet base flow however, as in Lighthill's theory, the auto-covariance tensor is assumed to be known, which invariably requires the use of Large-Eddy Simulation (LES) and experiments to obtain an approximate functional form for it. But LES data still uses immense computational resources and computing time when different nozzle operating points are needed for design optimization or when complex jets are considered. What makes any alternative to modelling so complex is that the turbulence closure problem precludes a closed-form theory for the auto-covariance tensor. However, our recent work revealed that the peak noise can be accurately predicted when the propagator is determined at low frequencies that are of the same order as the jet spread rate (that is lesser than unity). This proposal, therefore, sets out an alternative, first-of-its-kind, analytical approach to determine the fluctuating Reynolds stress for a given mean flow solution. By solving the governing equations at this asymptotic scaling where the jet evolves temporally at the same rate it spreads in space, we determine the Large-Scale Turbulence (LST) structure in the jet. This approach is defined by a 2-dimensional system of equations for an axisymmetric jet and the computational time is expected to be an order-of-magnitude faster than LES. The LST-based solution of the Reynolds stress auto-covariance for peak jet noise will be compared to LES data provided by our project partners at several jet operating conditions. We aim to show that the LST model of turbulence provides accurate noise predictions and is a viable alternative to LES.