The average annual worldwide repair and reconstruction costs following mechanical failures and earthquake damage alone has been estimated to be in the region of 40bn. Even this large figure does not include the virtually inestimable cost in human lives. Some of the major components of the 40bn loss are: 1bn due to commercial aircraft hull losses, 1bn due to repair and reconstruction following petrochemical industry disasters and 30bn following earthquake damage. The figures of most concern are those associated with post-earthquake costs, which are rising up to 20% pa. Earthquake damage is also of deep concern since the human and economic consequences are dire. During 1995, for example, the exceptionally damaging earthquakes in Northridge (USA) and Kobe (Japan) were estimated to result in financial costs of 165bn, a figure which was large enough to upset the entire global economy. Therefore it is very important that engineers devise improved methods for testing the strength of buildings and machines when they are subjected to such damaging forces. Engineers also predict the strength and integrity of structures and systems, before they are put into service. Essentially there are three ways by which this is done. The first is to build a full-size version of the system and subject it, via a test rig, to loads that are likely to be encountered in service, including earthquake-induced loads if appropriate. For all but the smallest of systems, full-size testing can be prohibitive in terms of cost and practicality. The second method is to build a smaller-scale model of the system and then subject it to correspondingly scaled-down loads on a laboratory test rig. Unfortunately, achieving compatible scaling of all aspects involved with strength and integrity is difficult to achieve with a physical model. Often, it may not even be possible to construct a truly representative scaled-physical model. This problem is the behaviour of many systems is not linearly dependant on scaling, so that scale-model testing can yield results of limited value. The third method depends on the derivation of a mathematical model, which is then solved by a numerical method, or simulation, on a computer. Although this form of modelling is not encumbered by the problems of scale, two issues dominate the acceptability of the results: firstly, the accuracy of the mathematical model and secondly, the ability of the numerical method to converge to the 'correct' solution. In practice, therefore, many engineering predictions are based on a compromised combination of all three methods.However, there is now a new and exciting alternative to the three methods, called dynamic substructuring, which enables us to test a combination of the critical, full-size, sub-components of the original system, linked to mathematical models of the remaining parts. This combination of physical sub-components and mathematical models must be controlled very precisely, using a computer, in order to properly represent the original system. The development of this method, and its control, forms the basis of this proposal. So, the principal objective will be to establish a unique world-centre for dynamic substructuring research called ACTLab / the Advanced Control and Test Laboratory. This will put the UK at the forefront of world research in advanced testing methods. More importantly, the UK will have a centre recognised worldwide for the contribution it makes to saving lives, preventing damage to the built environment and reducing the ultimate cost of natural or man-made disasters.Finally, it is not enough to practise science and engineering solely within a research environment. For this reason, we will be setting up an Educational Centre within ACTLab that will enable visitors to see the testing methods in action, to try out some of the methods for real and so understand how the methods work.

The resilience of communities and productivity of the nation is compromised by ill health. Musculo-skeletal disorders are one of the biggest expenditures in the annual NHS budget at approximately £5.4 billion, not including the hidden costs associated with loss of independence. This burden will increase with time not only because 1 in 4 citizens in the UK is expected to be over 65 years of age by 2045, but also due to the rising expectations of activity. At the same time, trauma is a leading cause of death and disability. Approximately 5.8 million people die each year as a result of injuries; this accounts for 10% of the world's deaths, 32% more than the number of fatalities that result from malaria, tuberculosis and HIV/AIDS combined. Trauma predominantly affects the young, who require swift return to physical activity and work, and interventions that will last them for life. Innovation in reconstruction of the musculoskeletal system at all stages of life is therefore paramount to ensure healthy, independent ageing. Currently, research into the biomechanics and reconstruction of injury is conducted largely by analysing sensor data (force, displacement, strain, high-speed photography) during the event, and assessing tissue failure after the event through dissection and imaging. What occurs precisely, however, at the vicinity of interest during loading, both prior to and at the time of failure, cannot be characterised truly unless a methodology is developed to 'look inside' while the event occurs. As the events of interest have millisecond durations, the temporal resolution of data acquisition needs to be far higher than what is possible with conventional clinical imaging equipment. We will combine high-speed photography with x-ray imaging in a way that it will enable us to perform radiostereometric analysis (RSA) with unprecedented sampling rates. This will be an internationally unique testing configuration allowing the system to be used with commercial and bespoke organ and tissue testing equipment. The Injury & Reconstruction Biomechanics Test Suite will enable experimental models of musculoskeletal trauma with detailed visualisation and quantification of the location and time of injury initiation and propagation, and so deliver a detailed picture of the mechanism of injury that we want to treat or mitigate. By enabling testing of prostheses and surgical interventions over a range of physiological, dynamic loading regimes, the Suite will allow for the quantification of the precise interaction between prostheses with human tissue and the evaluation of the efficacy of surgical interventions. This will not only promote further innovation in prostheses design and surgical techniques, but also the development of new, more appropriate and accurate qualification criteria for prostheses and surgical interventions. The Suite will enable the quantification of the motion and deformation of protective equipment, such as airbags or specialised clothing, and their precise interaction with the human body in unprecedented detail during the insult. This will inform the development of more biofidelic human surrogates for testing vehicles and protective equipment, provide robust data for the development and validation of computational models of human injury, and facilitate innovation in design of protective equipment for defence, automotive, and sport applications. The Suite will be an internationally unique national facility that has the potential to spawn exciting transformational research in musculoskeletal, orthopaedic and injury biomechanics, injury prevention, and surgical reconstruction, and enable its translation into practice for the improvement of lifelong health.

Actuation is the means by which forces can be applied within machine systems to give rise to controlled motion. Applications of actuation include, for example, the extrusion of material for manufacturing purposes, the manipulation of components in test machines, flight control surface adjustment in aircraft, ink jet printing, positioning in robotic systems, and active vibration/noise attenuation. There is a variety of actuator types based on different physical phenomena e.g. piezoelectric, electric, electromagnetic, pneumatic, hydraulic, and screw. The differences in performance relate to the amplitudes and frequencies of the forces that are capable of being applied, together with the motion range (stroke) and the associated precision. For example, piezoelectric actuators can deliver large forces at high frequencies, but the strokes are less than 1 mm. Alternatively, hydraulic actuators can deliver large forces over long strokes (e.g. 3 m in the opening of the Gateshead Millennium Bridge), though the frequency of the forcing is relatively low. An ideal actuator would have high performance over all metrics: force levels; frequency range or bandwidth; stroke range; and precision. At present no such actuator exists. The aim of the proposed research is to investigate the issues relating to physical characteristics, design integration and control that would enable actuation as close to the ideal to be realised. The future benefits would be widespread with the potential generation of new scientific and industrial innovations. The research will be focused on the design and integration of multi-actuation media with optimised control strategies to yield an actuator that has high performance metrics. A number of areas will be investigated. Firstly, piezoelectric actuators will be assessed for the generation of dynamic pressures within hydraulic cylinders, which would allow high frequency actuation. Additionally, piezoelectric devices will be used to deform piston and rod seals such that the friction forces provided by the seals may be used to control large stroke and high frequency motion. High frequency actuation and sub-micron control will also be achieved using a piezo-actuated valve for precise adjustment of hydraulic flows. The basic physical interactions of sliding and actuated parts will require in-depth analysis in order that the detailed design of high performance controllers can be accomplished using accurate system models. Finally, the integrated system will be realised in an experimental facility, which will be used to validate the research methodology.

The applications of hydraulics are diverse. Hydraulic actuation offers many benefits including compact and lightweight design due to high power density, fast response and good controllability. In most fluid power hydraulic systems, speed and force of the load are controlled using valves to throttle the flow and reduce the hydraulic pressure. This is a simple but extremely inefficient method as the excess energy is lost as heat, and it is common for more than 50% of the input power to be wasted in this way. An alternative method is to use a variable capacity hydraulic pump or motor. This is more efficient, but variable capacity pumps and motors are expensive.The proposed work investigates two methods of increasing the efficiency of hydraulic systems while maintaining good control of speed and force without the expense associated with variable capacity pumps. The first method is the Switched Reactance Hydraulic Transformer (SRHT), a novel device for controlling the flow and pressure of a hydraulic supply. The second method is the Electro-Hydrostatic Actuator (EHA). Both of these systems increase efficiency by removing the need for control valves. For both applications, active fluid-borne noise attenuation techniques may be necessary.Switched Reactance Hydraulic Transformer (SRHT):A new device for controlling the flow and pressure of a hydraulic supply is proposed. It consists of a high-speed switching valve and an 'inertance tube'. Acting as a transformer, the device is able to boost the pressure or flow. The device could be configured to provide the functionality of a variable capacity pump, a pressure relief valve, a pressure compensated flow control valve or a proportional valve. Each of these control modes can be achieved without an expensive variable capacity pump and without the inefficiency inherent in a control valve. Previous work highlighted problems of noise and parasitic power losses. If these problems can be overcome using more recent materials and techniques combined with careful design, it could provide a more cost-effective efficient alternative to pressure/flow control valves.Electro-hydrostatic Actuation (EHA):In EHAs, a variable speed electric motor drives a fixed displacement pump which delivers flow directly to a linear actuator. Moving from centralised power supplies to distributed multi-pump/actuator systems brings reductions in power levels for individual subsystems. Furthermore, valveless electro-hydrostatic actuation systems provide benefits of greater efficiencies compared to conventional valve-controlled hydraulic systems, further reducing the power requirements. EHA systems can suffer from noise problems because of the close coupling between pump and actuator, allowing direct transmission of pressure pulsation. The challenges are to achieve good dynamic performance while achieving higher efficiency, low noise and reduced system weight and size.Active Fluid Borne Noise Attenuation:Fluid-borne noise (FBN) is a major contributor to air-borne noise and vibration in hydraulic systems as well as leading to increased fatigue in system components. Although passive systems to reduce the noise have been shown to be effective, they require tuning to specific systems, their attenuation frequency range is limited and they may be bulky. Furthermore, attenuation devices based on expansion chambers, accumulators or hoses are likely to be unsuitable for EHA or SRHT systems as they add compliance to the system and would impair the dynamic response. Active devices, which add energy to the fluid to cancel out or destroy the pressure ripple to reduce noise levels, can be effective at a much wider range of frequencies and system designs without affecting the system's dynamic response. Both the SRHT device and EHA system may suffer from noise issues, and as such, will benefit from active noise attenuation.