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Item Open Access Adequacy of test standards in evaluating blast overpressure (BOP) protection for the torso(2016-11-18) Whyte, Tamlin; Horsfall, IanThe blast wave emanating from an explosion produces an almost instantaneous rise in pressure which can then cause Blast Overpressure (BOP) injuries to nearby persons. BOP injury criteria are specified in test standards to relate BOP measurements in a testing environment to a risk of BOP injury. This study considered the adequacy of test standards in evaluating BOP protection concepts for the torso. Four potential BOP injury scenarios were studied to determine the likelihood of injury and the adequacy of test standards for appropriate protection concepts. In the case of vehicle blast, BOP injury is unlikely and test standards are adequate. In the scenario involving an explosive charge detonated within a vehicle, and the close proximity to a hand grenade scenario, test standards are not available. The demining scenario was identified as of importance as test standards are available, but do not mandate the evaluation of BOP protection. A prototype South African Torso Surrogate (SATS) was developed to explore this scenario further. The SATS was required to be relatively inexpensive and robust. The SATS was cast from silicone (selected to represent body tissue characteristics) using a torso mould containing a steel frame and instrumented with chest face-on pressure transducer and accelerometer. The SATS was subjected to an Anti-Personnel (AP) mine test and the Chest Wall Velocity Predictor and Viscous Criterion were used to predict that BOP injuries would occur in a typical demining scenario. This result was confirmed by applying the injury criteria to empirical blast predictions from the Blast Effects Calculator Version 4 (BECV4). Although limitations exist in the ability of injury criteria and measurement methods to accurately predict BOP injuries, generally a conservative approach should be taken. Thus, it is recommended that the risk of BOP injuries should be evaluated in demining personal protective equipment test standards.Item Open Access The aerodynamic interference effects of side walll proximity on a generic car model(2010-11-03) Strachan, R K; Knowles, KevinThe flow around a generic car model both in isolation and in proximity to a near side wall has been investigated utilising experimental and computational methods. Phase one of this investigation tested a range of Ahmed generic road vehicle models with varying backlight angles in isolation, employing laser-Doppler anemometry, static pressure and aerodynamic force and moment measurements in the experimental section. Additionally, numerical simulations were conducted using a commercial Reynolds-averaged Navier Stokes (RANS) code with the RNG k-ε turbulence model. This phase served both to extend the previous knowledge of the flow around the Ahmed model, and analyse the effects of both the supporting strut and rolling road. Phase two then used similar methods to investigate the Ahmed model in proximity to a non-moving side wall. Results from phase two are compared with previous near-wall studies in order that an understanding of the effects of wall proximity can be presented, an area lacking in the existing literature. It is found that the flow on the isolated model must be understood before the effects of side wall proximity can be assessed. There is though, in general, a breakdown of any longitudinal vortices on the near-wall side of the model as model-to-wall distance reduces, with an increase in longitudinal vortex strength on the model side away from the wall. There also exists a large pressure drop on the near-wall model side, which increases in magnitude as model-to-wall distance reduces, before dissipating at separations where the boundary layer restricts the flow. Additionally, there is found to be a pressure drop on the top and bottom of the model with decreasing wall distance, with the relative magnitudes of these dependent on model geometry.Item Open Access Aerodynamic problems of urban UAV operations(2011-09-09) Kittiyoungkun, S; Saddington, A. J.; Knowles, KevinUnmanned Air Vehicles, UAVs are designed to operate without any onboard controllers. Consequently, they are considered to operate in a wide range of applications. Missions in undesirable conditions such as bad weather and/or highly unsteady gustiness could cause an unsuccessful operation. In many ways, aerodynamics is a key feature in the performance of UAVs such as influencing deformation vehicle, guidance and control. Two aspects of this research are, therefore, to understand flying conditions of UAVs in an urban environment and how the flying performance is affected by such conditions. The first objective relies on understanding air flow behaviour in the lower part of the urban environment which has the most important role on the response of UAVs. The second objective will be to look at the characteristics of a three-dimensional airfoil when it encounters an unsteady sinusoidal gust at different oscillation frequencies and freestream velocities. As the first step of the studies on the aerodynamic problem of UAV operations in the lower part of an atmospheric boundary layer in an urban environment, the boundary layer thickness in a suitable wind tunnel facility were the first experimental results obtained. Experimental measurements of the mean velocity profile in a turbulent boundary layer were investigated for three different floor roughness conditions as well as a smooth wall condition. As a result, three different boundary layer thicknesses were then classified depending on the wall surface roughness and a combination with turbulence generators providing a maximum thickness of 280 mm at the centre of the tunnel test section. However,the experimental investigations into the turbulent boundary layer over a rough wall have shown that the boundary layer thickness is dependent on the surface roughness and is different from that obtained under the smooth wall condition. An experimental study into a simulated urban flow regime was then carried out after the measurement of the boundary layer. Wind tunnel experiments on the airflow around a single and twin buildings including an investigation of the airflow between the gap of the buildings were obtained. Wind in the lower part of the atmospheric boundary layer is more a micro-scale problem which increases or decreases the wind speed induced by buildings nearby. The studies have found some strong concentrated vortices caused by the flow separation essentially independent of the nature of the upstream flow and usually as a direct result of the building geometry and orientation. As the measurement location increased further downstream from the back of the buildings, the concentrated vortices were found to be weak and disappeared into the wake region. Finally, an experiment was conducted using a sinusoidal gust generator to describe the effects of wind oscillation parameters such as oscillation amplitude, oscillation frequency and reduced frequency under static and dynamic conditions. An evaluation was made of the onset of dynamic stall due to rapid changes in angle of attack during an unsteady pitch motion. The NACA 23012 wing profile was tested at a fixed angle of attack condition with varying oscillation flow parameters. Results demonstrate that those parameters influence the dynamic stall and hysteresis loop based on lift coefficient and angle of attackItem Open Access Alternative explanation of North Korea's survival: successful application of smart power(2017-02-24) Shin, D. W.; Cleary, LauraThe original contribution of this study is to demonstrate how North Korea survives by using smart power. The existing literature has offered partial explanations, but many have lost their explanatory power over time and there seems to be no definitive answer to explain how North Korea survives. This multi-case study was designed to explore how the North uses smart power by examining its provocations from the Korean War to August 2015. The rationale for this study is to increase understanding of Pyongyang’s behavior and offer recommendations to bring long-term stability to the Korean Peninsula. This study purposefully began with the Korean War because it was assumed that, without understanding the origin of North Korean provocations, it would be difficult to provide the proper temporal context for other provocations. This study reveals that Kim Il-sung and his guerrillas consolidated power and established totalitarian rule dominated by his Juche ideology (self-reliance). Subsequently, they waged a long war of reunification from 1948 to the 1980s. Although Kim’s smart power attempts failed to achieve his principal aim of reunification, when Beijing and Moscow abandoned him in the early 1990s he focused on regime survival. He bolstered his weak hand by playing the nuclear card to buy more time to ensure the hereditary succession by his son Kim Jong-il, who defied predictions he would not survive and proclaimed Songun (military-first) to deal with the changing international environment. He demonstrated his own skill by exploiting Seoul’s Sunshine Policy and successfully negotiating three nuclear agreements with the U.S. After his death, Kim Jong-un waged a reign of terror to consolidate power and manufactured crises to bolster his legitimacy and demonstrate his leadership. He also invoked his grandfather’s anti-Japanese legacy and the Byungjin policy (simultaneous development of nuclear weapons and the economy) to legitimize his rule. The evidence shows he is rational and that offers opportunities to resolve the North Korea issue.Item Open Access Analysis of performance of automatic target recognition systems(2012-08-22) Marino, G.; Hughes, Evan J.An Automatic Target Recognition (ATR) system is a sensor which is usually able to recognize targets or objects based on gathered data. The application of automatic target recognition technology is a critical element of robotic warfare. ATR systems are used in unmanned aerial vehicles and cruise missiles. There are many systems which are able to collect data (e.g. radar sensor, electro-optic sensor, infra-red devices) which are commonly used to collect information and detect, recognise and classify potential targets. Despite significant effort during the last decades, some problems in ATR systems have not been solved yet. This Ph.D. tried to understand the variation of the information content into an ATR system and how to measure as well as how to preserve information when it passes through the processing chain because they have not been investigated properly yet. Moreover the investigation focused also on the definition of class-separability in ATR system and on the definition of the degree of separability. As a consequence, experiments have been performed for understanding how to assess the degree of class-separability and how the choice of the parameters of an ATR system can affect the final classifier performance (i.e. selecting the most reliable as well as the most information ii iii preserving ones). As results of the investigations of this thesis, some important results have been obtained: Definition of the class-separability and of the degree of classseparability (i.e. the requirements that a metric for class-separability has to satisfy); definition of a new metric for assessing the degree of classseparability; definition of the most important parameters which affect the classifier performance or reduce/increase the degree of class-separability (i.e. Signal to Clutter Ratio, Clutter models, effects of despeckling processing). Particularly the definition of metrics for assessing the presence of artefacts introduced by denoising algorithms, the ability of denoising algorithms in preserving geometrical features of potential targets, the suitability of current mathematical models at each stage of processing chain (especially for clutter models in radar systems) and the measurement of variation of information content through the processing chain are some of them most important issues which have been investigated.Item Open Access Antenna performance optimisation using evolutionary algorithms(2010-11-08) Ansell, D. W.; Hughes, Evan J.This thesis investigates the novel idea of using evolutionary algorithms to optimise control and design aspects of active array antenna systems. Active arrays differ from most mechanically scanned antennas in that they offer the ability to control the shape of their radiation pattern. As active arrays consist of a multiplicity of transmit and receive modules (TRMs), the task of optimally controlling them in order to generate a desired radiation pattern becomes difficult. The control problem is especially true of conformal (non-planar) array antennas that require additional phase control to achieve good radiation pattern performance. This thesis describes a number of significant advances in the optimisation of array antenna performance. Firstly a genetic algorithm (GA) is shown to be effective at optimising both planar and conformal antenna performance. A number of examples are used to illustrate and promote the basic optimisation concept. Secondly, in this thesis the techniques are advanced to apply multiobjective evolutionary optimisation algorithms to array performance optimisation. It is shown that Evolutionary Algorithms allow users to simultaneously optimise many aspects of array performance without the need to fine-tune a large number of weights. The multiple-objective analysis methods shown demonstrate the advantages to be gained by holding knowledge of the Pareto optimal solution set. Thirdly, this thesis examines the problems of optimising the design of large (many element) array antennas. Larger arrays are often divided into smaller sub-arrays for manufacturing reasons and to promote formation of difference beam patterns for monopulse operation. In the past, the partitioning has largely been left to trial-and-error or simple randomisation techniques. This thesis describes a new and novel approach for optimally subdividing both planar and conformal array antennas as well as improving gain patterns in a single optimisation process. This approach contains a new method of partitioning array antennas, inspired from a biological process and is also presented and optimised using evolutionary algorithms. Additionally, the technique can be applied to any size or shape of array antenna, with the processing load dependent on the number of subarrays, rather than the number of elements. Finally, the success of these new techniques is demonstrated by presenting a range of performance optimised examples of planar and conformal array antenna installations including examples of optimally evolved subarray partitions.Item Open Access An Approach to the evaluation of blast loads on finite and semi-infinite structures(2010-02-22T12:32:37Z) Rose, T. A.; Smith, P. D.This thesis is concerned with the use of Computational Fluid Dynamics techniques coupled with experimental studies to establish useful relationships between explosively generated blast loads and the principal aspects of the geometry of both single buildings and many buildings, as might be found in any urban environment. A method for the treatment of blast loading problems is described which is based on a large number of numerical simulations validated by key physical experiments. The idea of using numerical simulation to investigate aspects of How problems which are too difficult, expensive or time-consuming to consider experimentally is not new. The emphasis of this thesis, however, is not the treatment of specific problems but whole classes of problems. Chapter l introduces the diiiiculties associated with the evaluation of blast loads on structures. It briefly describes several existing techniques and introduces the approach suggested by this study. It also contains a number of useful deinitions which assist ap- preciation of the difficulties of numerical simulation of blast loading. Chapter 2 is in the form of a narrative and describes the process by which the solu- tion algorithm of the program used for the blast simulations (Air3d) was selected. The final choice, AUSMDV (a variant of the Advection Upstream Splitting Method) with MUSCL-Hancock integration (MUSCL standing for “Monotone Upstream~centred Scheme for Conservation Laws”), is essentially the combination of two methods which are “cheap” in terms of computational resources to obtain one of only moderate “expense” but which has sufiicient accuracy and robustness for these demanding applications. Chapter 3 contains a description of the computational tool Air3d, and it acts as a user’s guide to the program. Chapter 3 also contains a discussion of the treatment by the program ,Air3d of the processes which govern the formation of spherical blast waves in air. The chapter concludes with a comparison between the results of Air3d and a commercially available program and demonstrates the eflicacy of the solution algorithm adopted. Chapter 4 demonstrates the potential of the approach to obtain useful information in the main areas of application (Chapters 5 to 7) in this thesis. This is achieved by comparison of Air3d simulations with established sets of experimentally determined scaled blast parameters. Chapter 5 describes the problem of blast wave clearing, or loads on single finite struc- tures, and uses the approach to produce a relationship which is applicable over almost the whole range of practical interest to engineers. Chapter 6 is concerned with the effect of street width and building height on the blast overpressure impulses which load the facades of a street when an explosive incident occurs in an urban setting. It considers semi-infinite straight streets and describes, in broad terms, the limits of width and height which determine the blast impulse loads. Chapter 7 contains a discussion of the blast environment behind a serni~infinite protec- tive barrier wall when an explosive device is detonated on the near side. This problem has particular diiiiculties, which are discussed, and has illustrated the limits of the suggested approach. Chapter 8 summarises the approach adopted by this study for blast load evaluation, and it describes the progress made, difficulties encountered and the limitations of the method. Recommendations are made which would improve the approach for future in- vestigators, and the possibility of extending it for use in more varied applications is also considered.Item Open Access The Armed Forces of Australia, Britain and Canada and the impact of culture on joint, combined and multi-national operations : a methodology for profiling national and organisational cultural values and assessing their influence in the international workplace(Cranfield University, 2004-01) Stocker, A.; Taylor, Prof T.This study identifies the influence of national and military organisational values on the cultures of the armed forces of Australia, Britain and Canada, in order to assess the impact of culture on Joint, Combined and Multinational operations. This is achieved by: · Defining culture, values and related concepts. · Outlining a viable methodology to examine and profile cultural values. · Demonstrating why values form the basis of this study. · Reviewing the body of cross-cultural academic literature on cultural values and the military. · Executing a measurement of values in a consistent and academically sound manner. · Examining national influences on the culture of the armed forces of Australia, Britain and Canada. · Examining intra- national organisational influences on the culture of the services of the armed forces of Australia, Britain and Canada. · Examining international organisational influences on the culture of the services of the armed forces of Australia, Britain and Canada. · Focusing on the values of the armed forces examined in this study in order to compare the findings with the results obtained from the Values Survey Module. · Discussing the implications of the findings of this study and demonstrate how the values of the nations and organisations that have been examined can be expected to affect future operations.Item Open Access Arming the British Home Guard, 1940-1944(2011-09-19) Clarke, D M; Holmes, Prof E RThe Second World War saw British society mobilised to an unprecedented extent to meet the threat of Total War. ‘Total Defence’ was manifest in organisations such as the ARP and Home Guard. What sets the Home Guard apart was its combatant role. This thesis examines the arms provided for the Home Guard, and concludes that its combat power has been seriously underestimated. It benefitted from huge quantities of high quality smallarms purchased from the United States, which were not issued to the Regular Army, because they chambered American ammunition. What is extraordinary is that these weapons are always characterised as ancient relics, yet the oldest of them was years younger, in real and design terms, than the British Army equivalent. In 1940 Britain lacked the capacity to manufacture arms in the quantities needed to repair the losses of Dunkirk and meet the needs of the expanding armed forces. The remedy was unorthodox weaponry such as the ‘Sticky Bomb’ and the ‘Blacker Bombard’. These are always associated with the Home Guard, yet saw active service against the Africa Corps. These unconventional weapons were more capable than many modern authors suggest, but they suffer from an impenetrable ‘orthodox view’ that characterises Home Guard weapons as ancient, whimsical and inefficient. This has its origins in the Local Defence Volunteers’ disappointment when the Government failed to meet its promise to arm every volunteer; their dismay at receiving foreign equipment; the way in which the media portrayed the Home Guard; and the fact that the great threats the Home Guard existed to combat – invasion and subversion – appeared to be illusory, making the Home Guard itself seem quixotic. This study strips away that conventional narrative, and exposes a Home Guard that was well equipped for its tasks – frequently better equipped than other components of Home Defence.Item Open Access Artillery and Warfare 1945-2025(2009-11-24T18:18:23Z) Bailey, J P A; Holmes, Prof E RFor millennia battles were essentially affairs of linear encounter. From the 10th Century to the 20th Century, artillery generally fired directly in the two dimensional plane,limiting potential effects. The development of indirect fire changed this , two-dimensional model. Warfare became not so much a matter of linear encounter as one of engagement as cross and throughout an area; and artillery dominated land operations in both the First and Second World Wars as a result. Firepower was subsequently often applied in even greater weights, but its effects were frequently excessive and high-value targets proved elusive. During the Cold War in Europe,the importance of field artillery wanded relative to other arms. Artillery could only regain its utility by acquiring the highest-value targets and engaging them effectively with the appropriate degree of force in time and space true precision, as opposed to mere accuracy at a point. Improvements in target acquisition and accuracy will enable land systems once more to engage targets effectively throughout the battlespace with implications for warfare analogous to those precipitated by the introduction of indirect fire a century ago. Land operations will become increasingly three-dimensional and Joint. The effects of fire will increasingly be applied in, not merely via, the third dimensions, since targets themselves will increasingly be located, not just on the area of a battlefield, but in the volume of three-dimensional battlespace with values of indetermined by considerations of the fourth dimension, time. Fire, lethal and non-lethal, will also be targeted in other less tangible dimensions such as cyber-space and new types of 'virtual counterfire' will also emerge in the forms of legal and moral restraint. All will be viewed through the lens of perceptions. The burgeoning of firepower from all sources now becomes the spur for changes in the relationship between the land and air components, mindful of those novel factors that will increasingly inhibit the application of that firepower.Item Open Access Assessing the evidential value of artefacts recovered from the cloud(2017-06-14) Mustafa, Z. S.; Maddison Warren, Annie; Morris, S.; Nobles, P.Cloud computing offers users low-cost access to computing resources that are scalable and flexible. However, it is not without its challenges, especially in relation to security. Cloud resources can be leveraged for criminal activities and the architecture of the ecosystem makes digital investigation difficult in terms of evidence identification, acquisition and examination. However, these same resources can be leveraged for the purposes of digital forensics, providing facilities for evidence acquisition, analysis and storage. Alternatively, existing forensic capabilities can be used in the Cloud as a step towards achieving forensic readiness. Tools can be added to the Cloud which can recover artefacts of evidential value. This research investigates whether artefacts that have been recovered from the Xen Cloud Platform (XCP) using existing tools have evidential value. To determine this, it is broken into three distinct areas: adding existing tools to a Cloud ecosystem, recovering artefacts from that system using those tools and then determining the evidential value of the recovered artefacts. From these experiments, three key steps for adding existing tools to the Cloud were determined: the identification of the specific Cloud technology being used, identification of existing tools and the building of a testbed. Stemming from this, three key components of artefact recovery are identified: the user, the audit log and the Virtual Machine (VM), along with two methodologies for artefact recovery in XCP. In terms of evidential value, this research proposes a set of criteria for the evaluation of digital evidence, stating that it should be authentic, accurate, reliable and complete. In conclusion, this research demonstrates the use of these criteria in the context of digital investigations in the Cloud and how each is met. This research shows that it is possible to recover artefacts of evidential value from XCP.Item Open Access Assessing the Reliability of Digital Evidence from Live Investigations Involving Encryption(2009-11-24T17:34:14Z) Hargreaves, C. J.; Chivers, HThe traditional approach to a digital investigation when a computer system is encountered in a running state is to remove the power, image the machine using a write blocker and then analyse the acquired image. This has the advantage of preserving the contents of the computer’s hard disk at that point in time. However, the disadvantage of this approach is that the preservation of the disk is at the expense of volatile data such as that stored in memory, which does not remain once the power is disconnected. There are an increasing number of situations where this traditional approach of ‘pulling the plug’ is not ideal since volatile data is relevant to the investigation; one of these situations is when the machine under investigation is using encryption. If encrypted data is encountered on a live machine, a live investigation can be performed to preserve this evidence in a form that can be later analysed. However, there are a number of difficulties with using evidence obtained from live investigations that may cause the reliability of such evidence to be questioned. This research investigates whether digital evidence obtained from live investigations involving encryption can be considered to be reliable. To determine this, a means of assessing reliability is established, which involves evaluating digital evidence against a set of criteria; evidence should be authentic, accurate and complete. This research considers how traditional digital investigations satisfy these requirements and then determines the extent to which evidence from live investigations involving encryption can satisfy the same criteria. This research concludes that it is possible for live digital evidence to be considered to be reliable, but that reliability of digital evidence ultimately depends on the specific investigation and the importance of the decision being made. However, the research provides structured criteria that allow the reliability of digital evidence to be assessed, demonstrates the use of these criteria in the context of live digital investigations involving encryption, and shows the extent to which each can currently be met.Item Open Access Atomistic simulation of oxide materials with catalytic properties(2009-03-11T11:38:26Z) Măicăneanu, A.; Sayle, D.C.When supported, thin films demonstrate remarkable structural transformations, with important implications for catalysis, sensors, electrochemistry, semiconductors or superconductors. At present, the tools available to characterize solid-solid systems cannot provide atomic level resolution of, for example mixed screw-edge dislocations. Therefore atomistic simulation can provide an invaluable complement to experiment. In this work atomistic simulation was employed to generate models of oxide thin films. First an atom deposition methodology was used to create an SrO thin film on a BaO(001) support. The evolution of the thin film from small clusters (submonolayer coverage), to five atomic layers, which includes cracks in its structure, was studied. Specifically, information related to growth and nucleation processes can be explored using this methodology. Secondly an amorphisation and recrystallisation methodology was developed to explore the more complex system, that of ceria deposited on zirconia and yttrium stabilized zirconia. Simulated amorphisation and recrystallisation involves forcing the thin film to undergo a transformation into an amorphous state prior to recrystallising and therefore the recrystallisation process rather than the (perhaps artificial) initial structure will dictate the final structure. The recrystallisation process enables the evolution of all the important structural modifications as the thin film evolves structurally in response to the support. These include dislocations (pure edge and mixed screw-edge), dislocation networks, grain-boundaries and defects (interstitials, vacancies and substitutionals, including complex defect association) all within a single simulation cell.Item Open Access Baltic military cooperative projects: case study on effective military assistance programmes(2015-03-04) Ito, P K; Brudenell, A MFrom 1994, the Baltic states (Estonia, Latvia and Lithuania) undertook a number of cooperative regional military projects with the support of numerous Western countries. In particular, the Baltic Peacekeeping Battalion (BALTBAT) was an example of efficient Western defence cooperation to generate outcomes in order to achieve military and political goals. BALTBAT became the template for other Baltic programmes: the Baltic Naval Squadron (BALTRON), the Baltic Air Surveillance Network (BALTNET) and the Baltic Defence College (BALTDEFCOL). This thesis analysed the Baltic programmes, particularly BALTBAT, as a case study for identifying the elements of a model for effective military assistance projects. The focus was on the broad political decisions agreed upon by the donor and recipient states, such as the selection of development of peacekeeping capabilities, as the basis for military assistance, which provided the foundation for these initiatives. The value of the Baltic programmes as a case study and basis for identifying the elements of a model was enhanced by the fact that they succeeded at a delicate time in a sensitive region. The Baltic states had virtually no military forces upon regaining independence. Russia objected to Baltic state membership in NATO and was sensitive about a build-up of military capabilities close to Russian borders. In spite of these obstacles, the Baltic projects achieved outcomes which supported the military and political goals of the donor and recipient states. Analysis of the Baltic projects highlighted the importance of broad political decisions between donor and recipient states for military assistance initiatives. It also indicated the major factors (subsequently called Mechanisms) resulting from those decisions which were important to the outcomes from these programmes. These Mechanisms comprise the elements of a model which could be of value to academics and practitioners working in the area of military assistance.Item Open Access Behaviour of semi-rigid composite connections for steel framed buildings(2009-11-17T17:41:25Z) Muniasamy, D; Byfield, M PDuring propped construction the steel-concrete composite action resists dead as well as imposed loads. Conversely, the steel section alone resists the floor self-weight in unpropped beams. The major difference between propped and unpropped composite beams lies in the ductility requirements rather than in the strength requirements. Relatively few studies have been carried out to assess the rotation requirements for unpropped semi-continuous composite beams. The outstanding critical factor in the case of unpropped construction is the dead load stress that must be carried by the steel beam alone prior to hardening of the concrete. This research overcomes the difficulties involved in modelling the composite and noncomposite stages by using a numerical integration technique developed from the basic principles of structural mechanics. The method incorporates the fully non-linear material properties and requires very little assumption. The technique was initially validated using the experimental results from plain steel beam bending tests. The subsequent comparison between the model predictions and the results from the large-scale frame test carried out for this research purpose, showed that the method is capable of predicting non-elastic load vs. end rotation behaviour within a high degree of accuracy. Thus the model can be used with confidence in order to predict the connection rotation requirements for a wider range of loading configurations than is practically possible from experimental testing alone. A parametric study is carried out using the numerical integration technique developed for the semi-continuous composite beam on a total of 2160 different beam configurations, utilising different steel grades and loading conditions. In this study the influence of dead load stress on the connection rotation requirement has been thoroughly evaluated along with several other factors including span to depth ratio, location within the building frame, ratio between the support (connection) moment capacity and span (beam) moment capacity, loading type, steel grade and percentage of the beam strength utilised during design. The connection rotation capacity requirements resulting from this study are assessed to establish the scope for extending the use of composite connections to unpropped beams. The large-scale experiment that has been carried out provided an opportunity to investigate the behaviour of a modified form of composite connection detail for use at perimeter columns (single-sided composite connections) with improved rebar anchorage. Additionally, another extensive parametric study is carried out using the numerical integration technique developed for the steel beam to establish the influence of strainhardening on elastic-plastic frame instability design.Item Open Access Biologically inspired processing of radar and sonar target echoes(2017-10-31) Georgiev, Krasin; Balleri, AlessioModern radar and sonar systems rely on active sensing to accomplish a variety of tasks, including detection and classification of targets, accurate localization and tracking, autonomous navigation and collision avoidance. Bats have relied on active sensing for over 50 million years and their echolocation system provides remarkable perceptual and navigational performance that are of envy to synthetic systems. The aim of this study is to investigate the mechanisms bats use to process echo acoustic signals and investigate if there are lessons that can be learned and ultimately applied to radar systems. The basic principles of the bat auditory system processing are studied and applied to radio frequencies. A baseband derivative of the Spectrogram Correlation and Transformation (SCAT) model of the bat auditory system, called Baseband SCAT (BSCT), has been developed. The BSCT receiver is designed for processing radio-frequency signals and to allow an analytical treatment of the expected performance. Simulations and experiments have been carried out to confirm that the outputs of interest of both models are “equivalent”. The response of the BSCT to two closely spaced targets is studied and it is shown that the problem of measuring the relative distance between two targets is converted to a problem of measuring the range to a single target. Nearly double improvement in the resolution between two close scatterers is achieved with respect to the matched filter. The robustness of the algorithm has been demonstrated through laboratory measurements using ultrasound and radio frequencies (RF). Pairs of spheres, flat plates and vertical rods were used as targets to represent two main reflectors.Item Open Access Biologically-inspired machine vision(2013-09-25) Tsitiridis, A.; Richardson, Mark A.This thesis summarises research on the improved design, integration and expansion of past cortex-like computer vision models, following biologically-inspired methodologies. By adopting early theories and algorithms as a building block, particular interest has been shown for algorithmic parameterisation, feature extraction, invariance properties and classification. Overall, the major original contributions of this thesis have been: 1. The incorporation of a salient feature-based method for semantic feature extraction and refinement in object recognition. 2. The design and integration of colour features coupled with the existing morphological-based features for efficient and improved biologically-inspired object recognition. 3. The introduction of the illumination invariance property with colour constancy methods under a biologically-inspired framework. 4. The development and investigation of rotation invariance methods to improve robustness and compensate for the lack of such a mechanism in the original models. 5. Adaptive Gabor filter design that captures texture information, enhancing the morphological description of objects in a visual scene and improving the overall classification performance. 6. Instigation of pioneering research on Spiking Neural Network classification for biologically-inspired vision. Most of the above contributions have also been presented in two journal publications and five conference papers. The system has been fully developed and tested in computers using MATLAB under a variety of image datasets either created for the purposes of this work or obtained from the public domain.Item Open Access Blast analysis of composite V-shaped hulls : an experimental and numerical approach(2012-06-28) Follett, S.; Hameed, AmerDuring armed conflicts many casualties can be attributed to incidents involving vehicles and landmines. As a result mine protective features are now a pre-requisite on all armoured vehicles. Recent and current conflicts in Iraq and Afghanistan have shown that there is a requirement for vehicles that not only provide suitable protection against explosive devices but are also lightweight so that they may travel off-road and avoid the major routes where these devices are usually planted. This project aims to address the following two topics in relation to mine protected vehicles. 1. Could composite materials be used to replace conventional steels for the blast deflector plates located on the belly of the vehicle, and 2. How effective and realistic is numerical analysis in predicting the material response of these blast deflectors. It also looks into the acquisition and support of new equipment into the armed services, where the equipment itself is but one small element of the system involved. The first topic has been addressed by conducting a number of experimental tests using third scale V-shaped hulls manufactured from steel and two types of composite, S2 glass and E glass. These experiments found that, on a weight-for-weight equivalency, the S2 glass was by far the superior material, with very little damage to the outside shape of the hull. The steel was significantly deformed after testing and the E glass, although also did not deform as such, did experience a severe amount of matrix cracking leading to significant loss of structural integrity in that the hull could be easily flexed by hand after the tests. One S2 glass hull was also subjected to a further two explosive tests and although the amount of delamination was severe at the base of the hull there was very little geometry lost to the outside of the shape. The numerical modelling work consisted of the modelling of the mine blast phenomenon in autodyn and comparisons with published experimental and numerical work, with the results in reasonably good agreement. The second part consisted of comparing flat S2 glass plates subjected to varying charge sizes both experimentally and numerically in order to validate the material model, with good agreement. The final stage involved using the validated material model and re-creating the tests done on the V-shaped hulls. The results here at first were not in agreement, but with development of the model and the limitations from the experimental data collection methods applied a model that, when viewed with the experimental results, gave a reasonable representation of the experimental work was created. The management section of the thesis considers previous equipment purchases and what went wrong during their implementation. The Through Life Capability Management model is assessed in relation to an all composite vehicle and identifies some key questions and areas of concern, such as how the management of the DLOD trade-off process should be conducted.Item Open Access Bonded Repair of Composite Structures; A Finite Element Approach(2009-10-28T17:17:53Z) Odi, A. R. A.; Friend, Clifford M.This thesis addresses the issues surrounding the application of the finite element method to analyse composite structure repairs with an emphasis on aircraft applications. A comprehensive literature survey has been carried out for this purpose and the results are presented. A preliminary study and a comparative study of different modelling approaches have been completed. These studies aim to explore and identify the problems in modelling repairso n simplec ompositep anelsw ith speciala ttention given to adhesivem odelling. Three modelling approaches have been considered: Siener's model which is an extension of the traditional plane strain 2D model used for adhesively bonded joints, Bait's model which is a promising new approach and a full 3D model. These studies have shown that these methods are complementary providing a different insight into bonded repairs. They have also highlighted the need for a new modelling approach which will provide an overall view of bonded repairs. Improved modelling approachesh ave been developedf or externallyb onded patch and flush repairs. These models enable the study of adhesive failure as well as composite adherendf ailures.T hesea pproachesh aveb eena ppliedt o real repairs and the predicted results compared to experimental data. Four case studies have been conducted: external bonded patch repairs to composite plates, a scarf joint for bonded repairs, a flat panel repaired with a scarfed patch and a repaired curved panel. These case studies have shown that bonded repairs to composite structures can be analyseds uccessfullyu sing PC-basedc ommercialf inite elementc odes.Item Open Access British Cavalry on the Western Front 1916-1918(2008-12-02T14:15:26Z) Kenyon, D; Holmes, Prof E RThis thesis examines the activities and effectiveness of the British, Indian and Canadian cavalry which formed part of the British Expeditionary Force in France and Flanders (The ‘Western Front’) during the First World War. The study concentrates on the period from January 1916 to November 1918, focusing on four major Allied offensive battles; The Somme, July-November 1916 Arras, April 1917 Cambrai, November-December 1917 Amiens and the ‘100 Days’, August-November 1918 Other episodes of cavalry fighting associated with these offensives are also considered. It is argued in this study that the contribution of cavalry to the fighting on the Western Front has been consistently underestimated by historians, a trend which began with the Official History of the conflict and continues in even the most modern scholarship. The arm has been characterised as vulnerable to modern weapons, out of date, of little use in combat, and an unnecessary burden on scarce resources. Through analysis of the performance of mounted units in these battles, using data principally obtained from the unit War Diaries, as well as other primary sources, it is argued that cavalry were both much more heavily involved in fighting on the Western Front, and more effective, than has previously been acknowledged. The problems which constrained the performance of the cavalry are also exa mined. These included the limited understanding of their potential among senior officers, as well as command and control problems at lower levels. Issues concerning tactics, equipment, and interaction with other arms, (in particular tanks) are also examined. The evolution of the cavalry arm is also considered in the context of the evolution of the B.E.F. as a whole, and its part in the changing face of the conflict is examined, both as an agent of change, and as a beneficiary of wider developments in how the war was fought.