DSDS 24

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https://dspace.lib.cranfield.ac.uk/handle/1826/22139

In 2024 we celebrate the 10th anniversary of the Cranfield Defence and Security Doctoral Symposia!

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Open Access
High-rate, fracture testing methods
(Cranfield University Defence and Security, 2024-11-13) Sargeant, Ben; Davies, Catrin M.; Hooper, Paul; Cox, Mike
It is generally easier to break alloys at high speeds; in other words, fracture toughness reduces as strain rate increases. Understanding of these dynamic properties, by experimentation, reduces excessive conservatism in structural design, allowing for safe life extension of existing components and more efficient new constructions. This work investigates procedures to determine fracture toughness at elevated loading rates. Specific testing, used examples of different properties from Zinc, Aluminium and SA508-III pressure vessel steel, highlighting challenges in standard methods. Two methods of ‘rapid’ toughness testing have been contrasted – pendulum (Charpy) and servohydraulic (Very High Speed [VHS] Instron) test rigs. Charpy pendulums have a set energy input, hence a non-constant speed. Servohydraulic machinery adds energy to the system, maintaining speed. Both methods utilised sub-sized (10mm square bending specimens) specimens are recommended for high speed, minimising inertial effects and align with load capacities of high-rate instrumentation. Elevated speeds also make crack growth more difficult to monitor, compared to well understood static methods. Normalisation crack length monitoring (as recommended in standards) and a linear growth assumption from peak load have been utilised in this testing. Both methods produce similar crack length histories. Normalisation method anticipated the same crack growth initiation as peak load and showed a non-linear crack growth that aligns well with fracture surface features. However, the normalisation method is open to personal interpretation to fit data to a standard model. Results showed both testing methods to be dynamically invalid for brittle materials (Zinc and SA508-III steel at low temperature). Dynamic invalidity occurred as fracture occurred before (less than 93µs) kinetic energy effects are minimised - a requirement from standards for valid high-rate testing. Ductile materials (Aluminium and SA508-III steel at high temperature) were dynamically valid. Peak loads in Charpy data were clipped by relatively low sample rate. Peak loads in VHS testing were emphasised by high levels of ringing caused by impact shockwave resonating through the test rig. This let Charpy and VHS data to present different responses. Aluminium testing (low stiffness) loaded slow enough and damped ringing enough to produce comparable toughness data. Steel (higher stiffness) experienced these effects so much that data was incomparable. Improved system by higher sample rate Charpy instrumentation and higher mass and rigidity in the VHS test rig would reduce ringing (signal noise) and allow for better identification of accurate material response. The discrepancies between testing machines overwhelmed the effect of fixed energy input or speed controlled procedures.
Open Access
Environmental concerns when utilizing detonation as the clearance method for dumped munitions
(Cranfield University Defence and Security, 2024-11-13) Sharma, Bhumika; Webb, Sally; Temple, Tracey; Coulon, Frederic
Common methods for clearing dumped munitions include low-order and high-order detonations. Low-order detonations produce subsonic explosions, typically leaving behind large explosive fragments, while high-order detonations involve supersonic explosions, usually destroying the entire munition. However, both methods may result in incomplete combustion and the release of explosive materials into the aquatic environment. Additional environmental impacts include noise pollution, shock waves, metal toxicity, and the spread of bomb fragments. To therefore estimate the detonation hazards further experiments were conducted under controlled conditions using six 1000L Intermediate bulk container tanks. Explosive charges were detonated at both low-order and high-order detonations. On average, the low-order detonations (Tanks A & B) left 8.76 ppm of explosive residues, while high-order detonations (Tanks C & D) left significantly less residue, averaging 1.18 ppm. These values were based on a starting explosive concentration of 115 ppm before detonation. The findings confirmed that low-order detonations leave more explosive residue, leading to a higher risk of toxicity. High-order detonations, though resulting in less explosive residue, release fragments at high velocity, posing a serious environmental threat and increasing the risk of accidental explosions.
Open Access
Two-photon dual-comb LiDAR for non-cooperative targets
(Cranfield University Defence and Security, 2024-11-13) Nelmes, Alexander J. M.; Wright, Holly; Reid, Derryck
Open Access
Ontology-driven knowledge graphs for personnel management within the UK Ministry of Defence: a conceptual overview
(Cranfield University Defence and Security, 2024-11-13) Shufflebotham, A. Jack; Camelia, Fanny; Ferris,Tim
Ontology-driven knowledge graphs visualise complex relationships between entities such as people and concepts. This conceptual paper explores the potential for using ontology-driven knowledge graphs to enhance personnel management within the Ministry of Defence (MOD). It reviews existing literature on ontologies, structured frameworks to store domain knowledge based on relationships between data, and knowledge graphs and outlines the concept of an ontology-driven knowledge graph for a skill management system. The paper argues that this approach can provide a unified, standardised method for managing personnel skills, improving decision-making, and enhancing operational efficiency. A further benefit identified is the potential for the system to be expanded to exchange information with other systems, such as the NATO Defence Planning Process (NDPP), allowing external data to improve the quality of inferences made by the system.
Open Access
A systematic analysis and exposition of the Russian military term 'Maskirovka' [маскировка]
(Cranfield University Defence and Security, 2024-11-13) Verrall, Neil
This paper describes the progress to date of a part-time PhD on the topic of ‘Maskirovka’, in the context of the Russian (and Soviet) military. A mixed methods approach, utilising analytical techniques from language-based disciplines, such as applied linguistics, lexicography and translation studies, has been conducting a systematic exposition of the topic. The study has employed qualitative text-analysis, intertextual analysis and multimodal analysis on a repository of N=161 original source texts between 1914 – 2024, and N=39 Russian military dictionaries and lexica between 1795 - 2024. Some initial insights and findings are described
Open Access
Autonomy is the answer; what was the question?
(Cranfield University Defence and Security, 2024-11-13) Spayne, Peter; Lacey, Laura J.; Cahillane, Marie; Saddington, Alistair J.
Open Access
Emergent defence organising
(Cranfield University Defence and Secrity, 2024-11-13) Kace, Rob; Houghton, Peter
Defence Command and Control (C2) relies on socio-technical systems and hierarchical methods of organising functional elements. This paper builds from threat projections of future operational complexity to explore the Defence organisational limitations in coping with complex problems, and what type of organisational changes could help Defence start to achieve advantage within the inherent complexity of conflict. Through an understanding of some of the historical organisational contexts, the paper provides visualisations of the most significant C2 organisational capability gaps and proposes the development of a more effective Defence enterprise, using emergent relationships between loosely affiliated functional groups to deliver competitive advantage in complex future operating environments.
Open Access
Comparative sampling methodologies for detecting and quantifying 2,4,6 trinitrotoluene post-blast traces in water
(Cranfield University Defence and Security, 2024-11-13) Webb, Sally; Sharma, Bhumika; Temple, Tracey; Coulon, Frederic
This study addresses the analytical challenges associated with recovering explosive residues, focusing on the identification of 2,4,6-trinitrotoluene (TNT) in water samples. It evaluates the practicality, efficiency, and representativeness of three sampling methodologies: traditional grab sampling (GS), composite sampling (CS), and 3-D multi-increment sampling (3D-MIS). High-Performance Liquid Chromatography (HPLC) was employed for explosive identification. Post-blast sampling of TNT residues from high-order and low-order deflagrations was conducted to assess each method's efficacy and limitations in detecting trace and bulk contaminations. The experiments were conducted at the Alford Technologies Group range in Broadmead, UK, with analysis performed at the Defence Academy in Shrivenham, UK. Key findings highlight the varying effectiveness of each sampling method, with implications for enhancing detection sensitivity and accuracy in post-blast scenarios. This study underscores the importance of selecting appropriate sampling strategies tailored to different contamination scenarios, thereby informing more effective response protocols in CBRNE incidents involving water environments.
Open Access
Development of sustainable PPE for higher threat clearance operations by humanitarian organisations
(Cranfield University Defence and Security, 2024-11-13) Brown, Laura
In 2020 it was reported that 59 countries and territories were still contaminated by both landmines and other unexploded ordnance. The threats faced by those in the demining industry have increased due to the more frequent use of IEDs. These will generally have a larger charge size than conventional mines. PPE therefore needs to be improved to keep in line with these new threats. Recently there has been a push from industry to include more sustainable materials within armour production, with some already showing some promise within literature. Ramie (Boehmeria nivea) fibres have also been previously used in studies surrounding in soft armour, hard armour, and multi-layered armour system (MAS) and Flax (Linum usitatissimum) has been investigated with regards to hard armour panels. The hard panels manufacture for this project were produced using the vacuum resin infusion method, a low-cost method that is easy enough to be used in low scale operations. A number of different configurations were created, including natural fibre para-aramid and all natural fibre combinations, all of which were subject to different mechanical tests to assess their strengths. The ballistic testing, completed on a single stage light gas gun, showed the 50% Ramie 50% para-aramid panels outperformed all others tested. A significant observation was the different fracture mechanics seen on the back face of each of the panels, something that may have contributed towards their good performance. The all-natural Flax Ramie panels also showed some significant results, with these panels outperforming several other panels which contained para-aramid materials. Future work in this project will include assessing the best performing panels under increased ballistic loads, as well as looking at the suitability aspect of these panels to determine whether they can be potentially recycled once they have been used.
Open Access
Blockchain-based data-sharing acceptance among intelligence community
(Cranfield University Defence and Security, 2024-11-13) Muhamad, Wan Nurhidayat bin Wan
Data sharing among the intelligence community are critical to enable data analysis in supporting decision making hence preserving the security of the nation. However, sharing data between various parties is complicated due to the confidentiality and the risk of its exposure to unauthorised users and attackers. Hence, application of blockchain technology as a secure data sharing mechanism potentially safeguarding the data. However, the acceptance and readiness of the user to use this technology is questionable. This research aims to identify factors influencing user acceptance and to evaluate the acceptance level of blockchain-based data-sharing among the intelligence community in Malaysia by integrating Technology Acceptance Model 3 and Technology Readiness Index 2.0. This study applied an extensive literature review and empirical research using a survey questionnaire of data from 210 respondents from the intelligence communities. Descriptive and demographic data analysis using IBM SPSS software version 27 was used in this study. The acceptance model is analysed and verified using PLS-SEM method by using SmartPLS version 3.3.2. The results indicate that 10 out of 12 hypotheses is accepted and the acceptance is below moderate level. Hence, personality traits and feeling influenced the acceptance of the blockchain-based data-sharing system in the intelligence community. Overall, the result can assist the administration to manage the technology implementation process and to provides the system and architecture requirement in developing blockchain-based data sharing for the use of the intelligence community.
Open Access
Material strength at high pressure
(Cranfield University Defence and Security, 2024-11-13) Lonsdale, C. M.; McHardy, J. D.; Storm, C. V.; Roy, C. R.; MacLeod, S. G.; McMahon, M. I.
Over the past 30 years, advancements in the focusing schemes, beam quality, and X-ray brilliance at synchrotron light sources have enabled the reduction of X-ray beam dimensions from tens of micrometers into the sub-micrometer domain. These developments have enabled spatial mapping of the stress state at multi-megabar pressures in the diamond anvil cell. This work presents angle-dispersive X-ray diffraction results collected on beamline P02.2 at the Petra-III synchrotron using a beam size (FWHM) of 0.85 x 0.85 microns on an Ir sample. Variations in the local stress state in the sample were analysed through two approaches based on X-ray diffraction peak shifting and broadening. The results of the two methods are compared and highlight the effectiveness of Bi as a pressure transmitting medium, even at multi-megabar pressures. We look to apply these techniques to future experiments into obtaining more precise investigations of phase transitions and material strength at extreme pressure.
Open Access
Printing powerful powders: evaluating static and dynamic behaviour
(Cranfield University Defence and Security, 2024-11-13) Zyga, Jowita; McGee, Christine; Humphreys, Lisa; Stennett, Christopher
Additive Manufacturing (AM), commonly referred to as 3D printing, is a promising manufacturing technique, enabling near full control of the final product’s properties. With its unique approach to complex objects manufacturing, AM is investigated for its suitability of manufacturing with a wider range of materials. Despite the global research on AM of Energetic Materials that has already been conducted, final energetic devices often offer poorer product performance, compared to traditional manufacturing techniques. Reasoning for poorer outcomes could be attributed to the need for adapting and modifying Energetic Materials for AM purposes. To make the materials suitable for AM, there is a need for material modification, such as mixing energetic ingredient with solvent or binder, both of which often result in reducing the desirable outcome: the use of solvent can lead to uneven drying and shrinkage (and therefore producing voids within the product); too much binder is often responsible for low energetic density, therefore causing high burn rates and detonation velocities to be inaccessible. To overcome that, it would be beneficial to use raw, unmodified Energetic Materials – in their powdered form. Research conducted at Cranfield University, using Dry Powder Additive Manufacturing has proven, that energetic devices can be successfully printed using energetic powders. However, working with powders is often challenging: a lack of continuous flow, powder caking or powder-dispensing nozzle blockages are often experienced. To maximise the final product performance and avoid above issues, it is necessary to understand powder behaviour: its dynamic flow, bulk, shear and process properties. A deep understanding of those properties and their effect on manufacturing process is a crucial step to further developing this AM technique. Current methods of powder characterisation are typically limited to determination of 3 parameters: Angle of Repose, Carr (Compressibility) Index and Hausner Ratio. Scientific community have, however, proven these methods to be unreliable, proposing more thorough ways of powder studies: powder rheometers. Despite their growing popularity, analysis and interpretation of test results can still pose some challenges. Current research focuses on gaining better understanding of powder rheology and recognising how investigated powders’ properties translate to their behaviour during the printing process.
Open Access
Source detection and tracking for underwater distributed acoustic sensing
(Cranfield University Defence and Security, 2024-11-13) Drylerakis, Konstantinos Theofilos; Belal, Mohammad; Mestre, Rafael; Norman, Timothy J.; Evers, Christine
Distributed Optical Fiber Sensing (DOFS) transforms conventional fiber optic cables into an extensive network of continuous sensors. It achieves this by exploiting the spectral, polarization and/or phase sensitivity of the propagating light to measurands of temperature, strain, pressure, vibrations etc. To harness the novel capabilities of optical fibers to remotely capture, process and coherently analyze ambient vibration (e.g., acoustic) fields, it is crucial to address the challenges of the diversity of noise introduced in DOFS measurements, in particular, within the under-explored submarine environment. This research introduces a comprehensive workflow for the detection of active (uncontrolled) acoustic sources, comprised of successive denoising steps that deal with the distinctive properties of such environments. Leveraging the spatio-temporal density of DOFS measurements, we develop a method based on data covariances for the automatic extraction of features in an unsupervised manner, together with additional features introduced to distinguish active source signals from noise. Consequently, this work takes the denoising of underwater DOFS data one step further through the application of a tracking algorithm on real, novel submarine DOFS data, laying the foundation for broader applications of DOFS data analysis in marine environmental sensing and monitoring.
Open Access
Cultural Identity Value Intersectionality Calculous (CIVIC) An inductive study of British Army cultural sensemaking
(Cranfield University Defence and Security, 2024-11-13) Kace, Rob; Vincent, Dennis
Inductive PhD study, sponsored by the British Army and researched by a serving officer, to develop understandings of cultural value intersections within British Army organisations, from the internal, grounded perspectives of people that live that experience. The project application of an interpretivist social constructionist philosophy enabled the combination of Pike’s (1982) emic theory, that the people inhabiting a culture are best placed to understand it, with Crenshaw’s (1994) idea of interlocking power systems, and rejection of the analytical treatment of cultural axis in isolation, to develop Cultural Identity Value Intersectionality Calculous (CIVIC) as a sensemaking framework. Using the inductive reasoning of grounded theory, the project’s participatory research design enabled the audience-centric development of CIVIC as an intuitively usable framework for the emic sensemaking of audiences’ own Identity Value ‘Theories of Action’ and say/do gaps (Argyris & Schon, 1978). This addresses a gap in contemporary British Army capabilities, enabling volunteer participants to articulate their lived-experiences of organisational cultural dynamics (Schein & Schein, 2017) in terms of risks (Gigerenzer, 2002) and behaviour motivations (Atkins, West & Michie, 2014), within anthro-complexity (Snowden, 2020), to inform leadership initiatives and develop the force. This work highlights the importance of cultural intersectionality within the British Army, from the perspectives of the soldiers with that organisational lived-experience. It consequently delivers: (1.) Approach. An audience-centric risk-based approach to the sensemaking of cultural intersectionality; (2.) Method. A straight-forward, risk calculous method of systemic reasoning, using CIVIC to score participants’ cultural risks and build their agency for positive change; (3.) Knowledge-base. A thematic knowledge-base of qualitative evidence from the workforce grounded perspectives. This will enable the British Army leadership of tomorrow to leverage the best from a better informed, proactive, and contextually integrated future force, tackling cultural misconceptions and enabling competitive advantage within anthro complexity, through empowered organisational agency.
Open Access
High pressure structure of lanthanum
(Cranfield University Defence and Security, 2024-11-13) Roy, Callum R.; Storm, C. V.; Munro, K.; McMahon, M. I.
The behaviour of the lanthanum (La) metal at high pressure is of great interest because it provides insight into the behaviour of f electrons in high density metals, and also because high-pressure lanthanum hydrides have some of the highest superconducting temperatures known. Understanding the high-pressure phases of La is then vital in identifying the hydrogen content of these super-hydrides. However, the structure of La above 70 GPa is uncertain and a number of different, but related, structural forms have been reported in the literature. We have collected new, high-quality diffraction data to 230 GPa (2.3 Mbars) using the sub-micron diameter x-ray beam now available at the PETRA-III synchrotron. Analysis of this new data using Rietveld and Le Bail analysis reveals that La transforms to a body-centred tetragonal structure above ~80 GPa, a structure long-known in neighbouring element Ce, and confirming a previous unpublished experimental result from our group and a recent computational prediction.
Open Access
Supersonic flow field reconstruction using CNNs
(Cranfield University Defence and Security, 2024-11-13) Escudero, Miguel A.; Depuru-Mohan, Karthik; Marinus, Benoît G.; Saddington, Alistair J.
The accurate prediction of a projectile’s aerodynamic coefficients is crucial in high-precision external ballistic calculations. The aerodynamic forces and moments exerted on a projectile in flight influence key performance parameters such as range, accuracy, time of flight and stability. A large body of work has therefore been dedicated to understanding the flow dynamics around projectile bodies and obtaining the critical force and moment coefficients. This has been traditionally achieved in aeroballistic range experiments, wind tunnel set-ups and through the use of numerical models. Nevertheless, a widespread still exists between different techniques, revealing the fluid physics is not yet fully understood. A better understanding of the aerodynamics at play is accessible through a combination of the three techniques. However, reliable wind tunnel results will require matching a series of similarity parameters imposed by the firing conditions, which will inevitably relate to the physical scale of the models used. The size of small calibre projectiles may prove challenging for measurement in wind tunnel set-ups, however upscaling the models inappropriately will result in unrepresentative flow fields due to wall interactions and blockage effects. On the other hand, sting supports for wind tunnel models disturb a smaller portion of the flow with increasing projectile scale, particularly in terms of wake perturbation - a key contributor to aerodynamic coefficients. Clearly, scale effects have important consequences, however they have not been explicitly treated in the supersonic projectile literature. This study aims to explore the effects and limits of projectile scaling in supersonic wind tunnels, through a series of experimental techniques (Schlieren visualization, pressure measurements, force balance measurements...) and numerical modelling. Additionally, we aim to develop the Background-Oriented-Schlieren technique a step further through the use of machine learning models to reconstruct complete flow fields from optical data.
Open Access
Numerical modelling of hydrogen leakages in confined spaces for domestic applications
(Cranfield University Defence and Security, 2024-11-13) Thawani, Bonny
Open Access
CFAR detection in heterogeneous K- distributed sea-clutter background
(Cranfield University Defence and Security, 2024-11-13) Mungara, Nagarakshith R.; Balleri, Alessio
Detection of targets at sea is challenging due to unwanted echo returns from the sea surface, i.e. sea clutter returns. To account for the undesired effects of sea clutter at the receiver, and to control the probability of detection and false alarm, the K-distribution has often been used to provide a promising statistical fit to real clutter data. However, controlling the performance of the receiver becomes very challenging in heterogeneous clutter, that is when there is a sudden transition from one clutter region to another with a change in shape and/or scale distribution parameters. A possible solution to this challenge is to use some prior information on the sea clutter characteristics to generate clutter maps that inform adaptive detection solutions. This prior information can be obtained by the radar in real time (or close to real time) using oceanographic models, statistical clustering or potentially Artificial Intelligence.This research presents our first step in this direction by investigating detection in heterogeneous fully correlated K-distributed sea clutter. A transition line between homogeneous clutter regions is estimated using the statistical parameters of a K-distribution, to avoid polluting the training windows of a Constant False Alarm Rate (CFAR) detector with non-representative data. The transition cells assist to resolve the heterogeneous clutter into small homogeneous clutter regions and for every homogeneous region a CFAR detector is designed according to the K-distribution shape parameter. Results are obtained and presented for simulated data as well as for real sea clutter data provided by Hensoldt UK.
Open Access
Outer Space Treaty (OST) - blueprint for “peaceful uses” or pitfall for future conflict?
(Cranfield University Defence and Security, 2024-11-13) Miron, Samih Zaman
The Outer Space Treaty (OST) was enacted in 1967 in the context of the ‘Space Race’ between the US and the USSR, accelerated following the USSR’s launch of Sputnik in 1957. In recent years, rapid development of technology has enabled significant increase in the extent of activities in Space, resulting in many more States getting involved in the Space sector and the opening up of commercial activities that include the private sector. Thus, there has been a corresponding increase in the possibility of conflict arising from activities in Space, whether intentional or by mistake. Although there have been some initiatives in working on codes and guidance in the conduct of activities in Space, the position in key areas of conduct, accountability and enforcement has still to be clarified. This has important implications on the Laws of Armed Conflict (LOAC) given the increased risk of conflict and the particular characteristics of Space. This study will evaluate the “peaceful uses” wording in the OST through an International Relations (IR) lens and drawing on Comparative Adaptive Systems theory as to its context and subsequent practice.
Open Access
Improving adhesion in bonded ceramics through novel additively manufactured surface geometries
(Cranfield University Defence and Security, 2024-11-13) Powell, Daniel; Appleby-Thomas, Gareth; Painter, Jonathan
Many high-value industries (including medical, aerospace, and defence) utilise ceramics for their favourable properties, such as high hardness, low thermal / electrical conductivity, and chemical resistance. The latter property results from chemical inertness. However, this inertness leads to weaker bond strengths when joining ceramics with other materials, as is often required to overcome their brittle nature and low tensile strength.Geometries can be introduced to the surface of a material to act as adhesion promoters through increasing the surface area of the bond, but more interestingly through mechanical interlocking between the ceramic and bonding material. Whilst this would be impossible to achieve through conventional manufacturing techniques, additive manufacturing (AM) can create these novel surface geometries. This work pushes the capabilities of ceramic AM at a scale of no greater than 500 µm, finding the limits of the current technology. Furthermore, the potential for increased bonding through the generated geometries is investigated.