Pearly layers in seashells, also known as nacreous layers, are reported to be three orders of magnitude tougher than their primary constituent, aragonite. Their high toughness is attributed to a particular structure of alternating layers of natural ceramic and polymer materials. This work tries to emulate it using engineering materials. The thickness, strength, and stiffness of the ceramic layer; the thickness, stiffness, strength, and toughness of the polymer interface layer; and the number of layers are the factors that contribute to different degrees. Furthermore, understanding the relative contribution of different toughening mechanisms in nacre would enable identification of key parameters to design tough engineered ceramics. As a step towards that, in this thesis, layered ceramic beams replicating nacre were studied analytically, computationally, and experimentally. The insights and findings from these studies were then used to develop a new method to make tough layered ceramics mimicking nacre. Subsequently, the use of layered ceramics for armour applications was evaluated. Based on analytical numerical and experimental studies, we observed that the strength of the layers is a key factor to replicate the high toughness of nacre in engineered ceramics. We also demonstrated that, crack deflection and bridging observed in nacre in studies elsewhere, occur due to the high strength of platelets. Based on these findings, the new method developed in this study uses green alumina-based ceramic tapes stacked with screen printed stripes of graphite. During sintering, graphite oxidizes leaving empty channels in the stack. These channels were filled with tough interface materials afterwards. As a result, a ceramic- polymer composite with more than 2-fold increase in toughness was developed. Subsequently, we evaluated layered ceramics for armour applications based on numerical analysis validated with experiments. Consistent to the trends in literature, we observed that layers degrade the resistance to ballistic impact. However, improved energy absorption is demonstrated in layered ceramics. These conflicting dual trends were not presented and quantified in any earlier studies conducted elsewhere. Another new observation not documented earlier is the effect of interface strength. Using an interface material of sufficient strength, penetration resistance of layered ceramics can be improved beyond monolithic ceramics. Using these findings, new layered ceramic armour can be designed that is cost- effective and better performing than monolithic ceramics.

Stab resistant body armour had been used throughout history, with examples ranging from animal hide construction to the moulded Polycarbonate units typically used by United Kingdom (UK) Police Officers. Such protective articles have historically, and continue to present a number of issues which have shown to impair the operational performance of its wearer including but not exclusive to poor thermal regulation, large masses, and reduced manoeuvrability. A number of developments have been made in an attempt to minimise the effects of such issues. One potential solution yet to be fully explored is the utilisation of Additive Manufacturing (AM) technologies. In recent years the use of such manufacturing technologies, particularly Laser Sintering, has successfully demonstrated their suitability for a range of high performance applications ranging from Formula 1® to aerospace. Due to the fundamental additive nature of AM build processes, the utilisation of such technologies have facilitated the realisation of design concepts that are typically too expensive, difficult or impossible to create using traditional manufacturing processes. In order for AM technologies to be used for the generation of stab resistant body armour a number of historical issues and performance characteristics fundamental to ensure stab resistance is achieved must be satisfied. This body of research firstly evaluated the stab resistive performance of two of the most common materials suitable for Laser Sintering as highlighted by an initial review of AM technologies. Once an appropriate material had been highlighted it was used as the basis for further experimental testing. Such tests focussed on minimising the material thickness required to maintain an appropriate level of stab resistance within United Kingdom Home Office Scientific Development Branch (HOSDB) KR1-E1 requirement of 24 Joules of stab impact energy. Test results demonstrated that specimens manufactured from Duraform EX® required a minimum single layer thickness of 11.00 mm, and a dual layer total thickness of 9.00 mm to provide an appropriate level of stab protection within the HOSDB KR1-E1 standard. Coupled with the results generated from an investigation identifying the overlapping/imbricated assembly angle required to maintain an appropriate level of coverage across a scale structure, the stab resistant characteristics initially identified were used for the development of an imbricated scale-like assembly. Additional design features were also investigated to further minimise the total thickness of the final element design and corresponding assembled imbricated structure such features included angling strike surfaces and integrating a dual layered structure within individual elements. When the finalised imbricated assemblies were stab tested, they successfully demonstrated levels of stab resistance to the UK HOSDB KR1-E1 impact energy of 24 Joules.

This study examines four suits of armour that belonged to two Swedish kings, one protestant and one catholic, during the renaissance. The study tries to determine if it is possible to extract the religious identity of these kings based upon the decorations or other connotations of the suits of armour. Since the two kings, Erik the XIV:th and John the III, where half brothers and they succeeded each other, the suits of armour are closley matched in time and style.   The study also examines the grave effigy of one of the kings, John the III of Sweden, to examine if there is a connection between crossed legs on effigys and the perception of religion during the period.   The study is conducted through a archeological and historiological method and uses a combination theory of Smarts seven dimensions and the pictoral turn.   The main question of the study is: -          What does it take to track religious bias through armour? The subsequent questions are: -          Is it possible to find the religious identity in the suits of armour? -          Was the Gothicism movement a religious movement? -          The effigy of John the III was sculpted in a style popular in the eleventh century, created in the 16:th century and placed in the 18:th century. What conclusions can be drawn from this while also tracking the discourse of effigys in the same time expance.   The study concludes that if the identity of the owner of a suit of armour is known, the symbols that adorne the suit can be interpreted fairly well. It also conludes that the gothic movement in Sweden where an extremely aggressive catholic movement. Finally it concludes that the creation and placement of the tomb in Uppsala cathedral closely follows the different discourses about the meaning of crossed legs on effigys in Europe and that the makers most likely gave the position a devout religious connotation.

Med bakgrund i Black Lives Matter-demonstrationerna problematiserar den här studien två reklamfilmer från sport- och klädföretaget Under Armours (UA:s) kampanj The only way is through med syfte att studera hur normer och värderingar främjas utifrån jämlikhet och mångfald i UA:s reklamfilmer. Detta studeras genom att undersöka hur vita personer, färgade personer (POC) och personer med olika etnisk bakgrund representeras i UA:s reklamfilmer och vad det finns för likheter och skillnader mellan dessa representationer. Det teoretiska ramverket utgår ifrån Stuart Halls representationsteori och postkoloniala teorier om orienten. Med fokus på narrativet i reklamfilmerna analyseras denotationer, konnotationer och myter genom en semiotisk metod. Med hjälp av det semiotiska analysverktyget analyseras representationer av POC och personer med olika etnisk bakgrund utifrån ett postkolonialt perspektiv. Resultatet visade att det finns skillnader mellan de etniska representationerna och slutsatser dras om att främjandet av normer och värderingar utifrån jämlikhet och mångfald skiljer sig åt mellan reklamfilmerna. / Based on the Black Lives Matter demonstrations, this study problematizes two commercials from the sports and clothing company Under Armors (UA) campaign The only way is through with the goal of studying how norms and values ​​are promoted based on equality and diversity in UA's advertising. This is studied by examining how white people, people of color (POC) and people with different ethnic backgrounds are represented in UA's advertising and what similarities and differences there are between these representations. The theoretical framework is based on Stuart Hall's theory of representation and postcolonial theories of the Orient. With a focus on the narratives in the advertisement; denotations, connotations and myths are analyzed through a semiotic method. Using a semiotic analytical tool, representations of POC and people with different ethnic backgrounds are analyzed from a postcolonial perspective. The results showed that there are differences between the ethnic representations and conclusions are drawn that the promotion of norms and values ​​based on equality and diversity differs between the commercials.

The present study was intended as a new approach to the study of the military equipment of the Late Assyrian period which has traditionally relied upon the pictorial representations of the palace reliefs. By examining extant artifacts from the first millennium in their own right, with the reliefs merely serving to contextualize them, a truer understanding of Assyrian arms and armour can be gathered. This is necessary because the artwork only provides us with a filtered view of the real world, the reliefs are as much works of propaganda as of history. The approach taken here is to first examine the existing weapons typologically, and then to evaluate whether such weapon types appear to be accurately represented in contemporary artwork. Textual sources are also used where they can aid in the discussion. Five categories of arms and armour were studied: swords and daggers, spearpoints, shields, armour and helmets. The quality and quantity of the items in these categories varied significantly, providing for a much better representative sample of some items than others. Further questions concerning the possible ritual, rather than military, use of some of the existing artifacts were raised. However, the main conclusions reached were that the reliefs suffer not only from a propagandistic viewpoint which sometimes obscures the reality of Assyrian warfare, but that they also suffer from artistic license and spatial restraints, the difficulties in representing three-dimensional objects in a two-dimensional manner, the possible unfamiliarity of the artists with changing military technology and methods of construction, and finally, our inability to understand artistic short-hand for what were commonplace objects to the contemporary viewer. These have led to misunderstanding both as to the dating and chronological changes in weaponry, and also to the tactics used by the Late Assyrian military. This study of the artifacts themselves reveals a more mundane, utilitarian, and conservative military force which shows both a basic homogeneousness throughout the empire, and the myriad tiny variables of an army on the move drawing weapons and troops from many regions.

Cette thèse a été réalisée au sein des laboratoires du GEMTEX et du LAMIH, et porte sur l’étude et l’évaluation d’une solution composite à renfort tissé pour la protection balistique de véhicule. L’enjeu de cette thèse consiste à explorer le potentiel des solutions en composite à renfort tissé interlock 3D dans le cas d’unimpact à haute vitesse. Deux solutions composites ont été mis au point en laboratoire, intégrant le même renfort tissé interlock mais mis en oeuvre par deux procédés d'imprégnation différents. Ces composites ont été évalués à l’impact par un FSP (Fragment Simulating Projectile) de 20 mm de diamètre, dans une configuration de backing, c'est-à-dire en face arrière d’une plaque métallique utilisée pour la protection contre les impacts à haute vitesse.Plusieurs campagnes d’essais ont été réalisées permettant d’optimiser nos structures interlocks 3D afin de répondre au mieux à la sollicitation dynamique. Les résultats à l’impact de ces composites ont été comparés à ceux d’une solution composite dite de référence généralement utilisée dans les véhicules blindés à base de tissés 2D empilés suivant différentes directions. Ces essais nous ont permis de faire ressortir les performances de l’une des structures développée présentant des capacités de protection à l’impact supérieures aux composites de référence.Afin d’en comprendre les mécanismes des renforts mis en jeu, nous avons représenté numériquement ces tissus interlocks soumis à l’impact. Des modèles numériques innovants ont été simulés dans le but de représenter le renfort tissé de façon réaliste grâce aux mesures obtenues par micro-tomographie à rayons X. / This thesis was performed at the laboratories of GEMTEX and LAMIH on study and evaluation of a solution based on warp interlock reinforced composite for vehicle ballistic protection. The main purpose of this thesis is to explore the potential of warp interlock reinforced composite solutions in the case of a high velocity impact. We have chosen to study two composite solutions manufactured in our laboratory which presented the same warp interlock reinforcement but with different resins and infusion processes. Those composites were tested by an FSP (Fragment Simulating Projectile) impact as armour backing. Few campaign of tests were performed which helped us to optimize our warp interlock structure in order tohave a better response to the dynamic loading. The impact results of our composites have been compared with those of the benchmark which is a composite generally used backing. Thanks to these tests we had the possibility to observe that one of our structures present a better impact behaviour than the others. In order to improve our representation of those reinforcement, we have been working on the numerical modelling of those warp interlock submitted to impact. Innovative numerical models have been set up thanks to micro-tomography analysis allowing a more realistic representation of the reinforcement.

A presente pesquisa trata das relações entre trabalhadores, militantes ligados ao Partido Comunista do Brasil (PCB) e a comunidade fronteiriça de Santana do Livramento e Rivera, a partir da instalação na região do Frigorífico Armour, e especialmente durante o período de redemocratização da sociedade brasileira que se seguiu ao final do Estado Novo, em um recorte que compreende o período de 1945 a 1954. Tem por objetivo revelar as articulações políticas e lutas operárias que tiveram como protagonistas os militantes ligados ao PCB e a sociedade fronteiriça no período em que o partido viveu um breve momento de legalidade, que por fim iria desaguar em forte repressão e na chacina ocorrida em 24 de setembro de 1950, na linha divisória entre Brasil e Uruguai. Dividida em quatro capítulos, busca historicizar a trajetória de homens e mulheres que tomaram parte dessa busca por direitos e justiça social em uma sociedade que tinha na grande fábrica multinacional o motor de desenvolvimento e também de concentração de poderes. Para tanto utiliza um conjunto de fontes composto por entrevistas, periódicos, acervos particulares, Anais da Assembleia Nacional Constituinte de 1946 e da Câmara de Vereadores de Santana do Livramento, textos literários e manuscritos. / This tesis concerns about the relations between workers, militants linked to the Communist Party of Brazil (PCB) and the border community of Santana do Livramento and Rivera, since the installation in the region of the Armour meat packers company, and especially during the period of redemocratization of Brazilian society which followed the end of ―Estado Novo‖, in a cut that covers the period from 1945 to 1954. The objective is to reveal the political articulations and workers' struggles that had as protagonists the militants linked to the PCB and the border society in the period in which the party Lived a brief moment of legality, which would eventually lead to strong repression and the slaughter that occurred on September 24, 1950, on the dividing line between Brazil and Uruguay. Divided into four chapters, it seeks to historicize the trajectory of men and women who took part in this search for rights and social justice in a society that had in the great multinational factory the motor of development and also concentration of powers. In order to do so, it uses a set of sources composed of interviews, periodicals, private collections, Annals of the Constituent Assembly of 1946 and the Council of Councilors of Santana do Livramento, literary texts and manuscripts.

Soft body armour is usually constructed by layering numerous layers of the same fabric. Such a construction, however, may not be the most efficient in providing the required protection due to different ballistic resistant efficiency of each layer. This research aims to optimise the construction of the panels for soft body armour by hybridisation in order to achieve the improvement of ballistic performance and reductions in weight. Twaron woven fabrics with different weave structures and Dyneema uni-directional (UD) laminates were used as components for the hybrid design of panels. Two complementary research approaches were employed in this study, namely the empirical method and the Finite Element (FE) analysis. The first part of this research systematically revealed the different ballistic characteristics of each layer in different positions of an armour panel and the way of energy absorption in the panel. The fabric layers in the front, middle and back of the panel exhibited different extent of transverse deformation and stress distribution. The energy absorption increases from front layer and reaches to the maximum value in the last perforated layer and then decreases gradually in the following back layers. Such pattern of energy absorption was not affected by either the striking velocity or the total number of layers in the panel, but the position, in the thickness, of the peak value in energy absorption was shifted more towards the back of the panel when the striking velocity increases. Such findings contribute to the understanding of different ballistic responses in different positions of an armour panel under ballistic impact. The second part of this research put forward a new hybrid design concept. According to above theoretical understandings of different ballistic characteristics in different positions of an armour panel, the fabric layers in the panel were discretely divided into three groups. In addition to the performance of different components for the panel and the influences of the laying sequence, a procedure for constructing hybrid armour panels has been established. The first group was composed of the first few layers on the striking face. The heavyweight fabrics as heat resistant layers were used in this group to resist the heat generated on the striking face. The second group contained some middle layers close to the last perforated layers. The lightweight fabric was combined in this group due to the higher energy absorption capacity. All back layers were classified into the third group. Dyneema UD laminates were placed in this group to constrain the large transverse deflection of the lightweight fabric and to minimize BFS of the panel. Two hybrid panels were designed and evaluated. In the perforation ballistic tests, the hybrid panel was more likely to stop the projectile compared to Twaron woven panels with the same areal density. In the non-perforation ballistic tests, the hybrid panel exhibited significantly lower BFS and achieved the reductions in weight. Such hybrid design makes best use of different available materials to achieve the improvement of ballistic performance and lightweight of a panel. It has a practical significance for the soft armour panel design.

Flexible risers that carry hydrocarbon fuels from the subsea facilities to the floatation units above the sea surface are composed of multiple metallic and polymeric layers (in their wall). Among these layers, the tensile armour layer consists of several helically wound metallic wires; these tensile armour layers carry the weight of the riser, provide tensile stiffness & strength and maintain the structural integrity of the riser structure during harsh underwater currents. However, as the oil & gas fields in shallow waters are receding, the oil & gas industry is being forced to move towards deeper offshore waters, where the metallic tensile armour wires pose limitations (fatigue, corrosion, weight, etc.). In this thesis an alternative to metallic tensile armour wires will be presented in form of a flexible hybrid composite formed by stacking seven pultruded composite (carbon and vinyl-ester) circular rods in form of hexagonal pack, held together by an over-braid (Dyneema fibres) sleeve. The manufacturing process for hybrid composite tensile armour wires will be studied and their mechanical properties will be presented. A multi-scale finite element model developed for hybrid composite wires will be presented in this thesis to help further understand the mechanical properties of hybrid composite wires.

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