In this dissertation, the rate of the BFD during body armor impact is characterized with fiber Bragg gratings for the first time ever. The depth rate is characterized using a single fiber optic sensor, while the entire shape rate can be characterized using multiple fiber optic sensors. This is done with a final depth accuracy of less than 10% and a timing accuracy of 15% for BFDs as deep as 50 mm and impact event of less than 1 millisecond. The shape sensing method introduced in this dissertation is different from traditional fiber optic sensor shape reconstruction methods in the fact that strain from the kinetic friction regime is used rather than the static friction regime. In other words, information from the fiber optic sensors slipping is used to reconstruct the shape in this work, whereas strain from the fiber optic sensor remaining fixed to a reference is used for typical fiber optic shape sensing purposes.

Ce projet s’intéresse à un objet particulier : l’armure. Celle-ci, dont la fonction première était de protéger le combattant, s’est adaptée entre le XIIIe et le XVIIe siècle aux bouleversements qu’ont connu les pratiques de guerre et l’organisation des armées dans cette période. L’armure pouvait aussi avoir une autre fonction, celle de distinguer socialement son porteur. Ainsi, à la fin du Moyen Âge l’armure est à la fois un objet de grande consommation et d’usage courant mais également un produit de luxe. Sa fabrication, dominée par différents centres de productions internationaux comme les villes Milan et Nuremberg, demandait un savoir-faire spécifique pour travailler et mettre en forme le métal.Dans le but d’éclairer d’une part les techniques et savoir-faire anciens, d’autre part la circulation et les échanges dans l’espace européen, ce projet aborde l’étude de l’armure par sa matérialité, en mettant en œuvre une approche archéométallurgique. Un corpus spécifique, de plus d’une centaine d’objets, caractéristique de l’évolution de l’équipement défensif des combattants mais également des grands centres de production européens a ainsi été constitué. L’analyse du métal a permis de déterminer la nature des matériaux employés ainsi que les techniques de fabrication de ces objets. L’étude des inclusions non métalliques a quant à elle permis de discuter de l’origine géographique du métal utilisé pour la fabrication des pièces.De façon générale, les résultats ont montré l’emploi d’alliages de natures variées, parfois très hétérogènes pour réaliser les plates d’armures. Néanmoins en moyenne le métal employé possède une dureté proche de celle d’un acier homogène à 0,4-0,5% de carbone. Les alliages trempés de dureté élevée demeurent très minoritaires dans le corpus étudié. Des spécificités ont néanmoins été relevées, comme l’utilisation d’un matériau spécifique, associant plusieurs feuilles de métal aux propriétés différentes qui pouvait offrir à l’armure de meilleures propriétés défensives. Les informations acquises ont également permis d’étudier les pratiques mises en œuvre par les armuriers que ce soit pour la fabrication d’une armure complète, la production massive de pièces en « série », ou issues d’un même atelier. Les résultats relatifs à la nature et au travail du métal nous ont ainsi amené à questionner le rôle du maitre armurier qui signait les objets et la signification de cette signature pour un atelier. / The project focuses on a specific object: armor. Between the 13th and early 17th centuries, war practices have undergone major changes, both on the technological level, as well as the organizational one. Accordingly, defensives arms were adapted to the new needs in order to protect their owners. Armor was also in some cases a mark of social distinction. Thus, at the end of the Middle Ages, armor was both an object for everyday military use, massively produced, and a luxury attire. Its fabrication was dominated by several prestigious European centers of production like Milan and Nuremberg and required specific technical skills to shape the metal.In order to shed light on some of the techniques and ancient skills, along with the circulation and exchanges in the European space, this project addresses the study of armor through its materiality, by implementing an archeometallurgical approach. A specific corpus of over a hundred artefacts was collected, characteristic of the evolution of the defensive equipment of the fighters but also of the great European centers of production. Physicochemical analysis of the metal can decipher its nature and reveal the technical skills of the craftsmen. Non metallic phases analysis has allowed to test hypotheses on the provenance of the materials employed.Overall, the results showed the use of alloys of varying nature, sometimes highly heterogeneous, to realize the plates of armor. However, on average the metal employed has a hardness close to a homogeneous steel with 0.4-0.5% carbon. Hardened alloys of high hardness remain very minor in the studied corpus. Specificities were nevertheless noted, such as the use of a specific material, combining several sheets of metal with different properties that could offer better defensive properties. The information acquired also allowed to study the workshop practices implemented by the armorers, whether for the manufacture of a complete set of armor, the mass production of "serial" pieces, or those originating from the same workshop. The results relating to the nature and hammering of the metal have led us to question the exact nature of the intervention of the master armorer who signed the artefact and the significance of the signature of a workshop.

Naturally occurring armor has evolved in many different classes of organisms, often in response to predation, although other factors may play a part. In this study, the scales of the benthic armored fish Agonopsis vulsa were examined for damage patterns in order to illuminate the life history and environmental interactions of the fish. Scales from the fish were systematically destroyed in the lab, and observations made from the damaged scales were used to create a categorical damage rating, which was applied to 34 specimens ranging in trunk length from 2.3 cm to 14.2 cm. The specimens were rendered as three-dimensional digital models after being scanned with a micro-CT scanner. During data analysis, the damage categorization was simplified to a binary of damaged vs. undamaged and statistical significance of damage was calculated using probability loop simulations. Statistically significant damage was found in a few small clusters across the ontogeny, consistent with predation and intraspecies competition. This study is also suggests that the flattening of ventral scales in A. vulsa is not congenital. The scales are most likely ground down by constant friction against the sea floor over the lifespan of the organism.

Current body armor technologies need further improvements in their design to help reduce combat injuries of military and law enforcement personnel. Kevlar-based body armor systems have good ballistic resistance up to a certain ballistic threat level due to limitations such as decreased mobility and increased weight [1,2]. Kevlar fibers have been modified in this work using a nano-scale boron carbide coating and a marked increase in the puncture resistance has been experimentally observed. It is hypothesized that this improvement is due to the enhancement of the mechanical properties of the individual Kevlar fibers due to the nano-scale coatings. This study presents a comprehensive experimental investigation of individual Kevlar fibers based on nanoindentation to quantify the cause of the enhanced puncture resistance. The experimental setup was validated using copper wires with a diameter size in the same order of magnitude as Kevlar fibers. Results from nanoindentation did not show significant changes in the modulus or hardness of the Kevlar fibers. Scanning Electron Microscopy revealed that the coated fibers had a marked change in their surface morphology. The main finding of this work is that the boron carbide coating did not affect the properties of the individual fibers due to poor adhesion and non-uniformity. This implies that the observed enhancement in puncture resistance originates from the interaction between fibers due to the increase in roughness. The results are important in identifying further ways to enhance Kevlar puncture resistance by modifying the surface properties of fibers.

Coastal regions are extensively utilized by constructing coastal structures and facilities, as a result of the economical potential they offer. In designing and construction of coastal structures, it is important to achieve an optimum design satisfying both the stability and the engineering economy requirements effectively, regarding the natural balance of the coastal region. In this study, first step model tests on the stability of the coastal protection structures of Eastern Black Sea Highway Project under construction, proved that the structure is not stable and safe under severe wave action. As an innovative approach, using Van der Meer&amp / #8217 / s approach and berm design guidelines alternative cross sections were generated.In the second step of the model studies, 8 different models were constructed using a model scale of 1/31.08 and they were tested both for breaking and non-breaking waves. The experiments took place in the Coastal and Harbor Engineering Laboratory of the Middle East Technical University, Civil Engineering Department. The newly designed and optimized berm type structure was proved to be successful and economical.

No description available.

With increased military personal protection equipment, body armor, comes the addition of carried load. Such person protection in recent history has been instrumental in combating the imminent threats (e.g., improvised explosive devices) of hostile environments, preventing otherwise lethal injuries. However, body armor has been suggested to degrade warfighters’ performance and compound the risk of musculoskeletal injuries. Both performance and risk of injury are intensely related to joint biomechanics. Therefore the objective of this project was set to determine the immediate and prolonged effects of wearing body armor on biomechanics of the lower back and knee. A randomized cross-over study design, wherein 12 sex-balanced, physically fit, young participants completed a series of tests before and after 45 min of treadmill walking with and without body armor. Tests included two simple tests (i.e., toe-touch and two-legged squat), two military inspired tests (i.e., box drop and prone to standing) and four knee torque tests (i.e., maximum isometric contraction of knee flexors and extensors, and concentric and eccentric isokinetic contraction of knee flexors and extensors. During these tests, kinematic, kinetic and torque measurements were used to investigate the immediate and prolonged effects of exposure to body armor on several measures of knee and lower back mechanics related to performance and risk of injuries. For the simple tests, the immediate effects of body armor were an increase of > 40 ms (p ≤ 0.02) in flexion duration of the dominant joint and an ~1 s (p ≤ 0.02) increase in overall test duration as well as an ~18% (p = 0.03) increase in the lumbopelvic rhythm ratio near mid-range trunk flexion. For the military inspired tests, the immediate effects of body armor were an increase of ≥ 0.02 s (p ≤ 0.001) in temporal test durations and an increase of ~158 N (p = 0.01) box drop peak ground reaction force. Finally during the dynamometer testing, the BA condition was found to cause a greater reduction, ~10 N•m, in the maximum isometric strength of knee flexors (p = 0.04) and an increase (p ≤ 0.03) of strength ratios compared to the no armor condition.

While military body armor is used among warfighters for protection on and off the battlefield, it has been suggested to impede performance and act as a risk factor for the development of musculoskeletal disorders, especially low back pain. Apart from personal suffering, low back pain in soldiers is a great economic burden on the US economy. The objective of this study was to quantify the changes in trunk mechanical and neuromuscular behavior following prolonged exposure to body armor compared to exposure without. A crossover study design was used where 12 sex-balanced participants completed a series of tests before and after 45 minutes of treadmill walking with and without body armor. The tests included range of motion, isometric trunk tests, sudden perturbations, and stress relaxation. As a whole, exposure duration considered in this study resulted in no significant differences in performance between armor and no armor conditions. However, comparing the effects of body armor among the sex-differentiated groups showed a body armor -induced increase in range of trunk motion in the sagittal plane among females (p = 0.0018) and a decrease in pelvic range of motion in the transverse plane among both males (p=0.025) and females (p=0.004).

O presente trabalho tem como objetivo avaliar as tensões atuantes no conjunto conector e duto flexível de camadas não aderentes durante ensaios com carregamentos axiais de tração e fadiga. Estes ensaios são utilizados para a qualificação de dutos flexíveis. Foram desenvolvidos e patenteados alguns modelos de conectores contemplando apenas a parte estrutural. Ensaios preliminares de tração e fadiga, com dois conectores diferentes e um segmento de riser de dimensões reduzidas, foram realizados visando a seleção do modelo de melhor desempenho em um pórtico. O conector de melhor desempenho foi então ensaiado em uma bancada com dimensões que atendessem ao documento da Petrobras a I-ET 3500.00.6500-291-PAZ-001 - Non standartized Prototype qualification tests of flexible pipes (2007). Tanto os ensaios do pórtico como o de bancada, foram monitorados com strain gages colados nos tendões da armadura externa de tração próximos aos conectores. O foco deste trabalho está nas armaduras de tração na interface com a resina do conector. Questões quanto ao desempenho da mesma em fadiga são de grande importância prática. Complementando a parte experimental, foram construídos modelos sólidos tridimensionais, baseados no Método dos Elementos Finitos para análise das tensões. A comparação dos resultados das diferentes metodologias validou o modelo numérico possibilitando melhor entendimento das variações de tensões nas armaduras de tração na interface com os conectores. Isso possibilitou responder a importantes questões quanto ao desempenho em fadiga bem como possíveis melhorias no projeto de conectores para dutos flexíveis. Existem trabalhos referentes à análise de tensões dos tendões nos conectores considerando o estado plano de tensões. O presente estudo dos tendões usando modelos tridimensionais, abordagem não encontrada em literatura aberta, avalia melhor a concentração de tensões nos tendões na entrada do conector. A motivação deste estudo se deve tanto à falta de informações detalhadas das tensões e deformações nos tendões na interface com o conector, como pela importância das mesmas, em componentes vitais à explotação de petróleo Offshore. / This aim of this work is to evaluate stresses which actuate on a system made up of a unbonded flexible pipe and a end fitting during static and dynamic axial loading mechanical tests. These tests are used as a means of qualification of flexible pipes. The structural design of models of end fittings were developed and patented. Preliminary static and dynamic tests with two different end fittings and a smalldimensioned riser segment were performed in a frame in view of selecting the bestperforming type. After this evaluation, the end fitting with the best performance was tested in a rig with dimensions according to Petrobras document I-ET 3500.00.6500-291-PAZ- 001 - Non standartized Prototype qualification tests of flexible pipes (2007). Tests performed in the frame and on the rig were monitored with resistance strain gages attached to wires of the external armor, on the interface with the end fitting resin, since performance of this region under fatigue is of utmost practical importance. Three-dimensional solid models were built using the Finite Element Modelling (FEM) method, as a way of validating experimental results. Comparison of results obtained from the different methodologies validated the numerical model, allowing a better understanding of the variations of stresses in the interface of the riser with the end fitting. This led to the solution of many doubts regarding fatigue performance as well as possible improvements in the design of flexible riser end fittings. Existing work published in literature considers only plane stress; the present study, based on 3D models which are not found in literature, is thought to better describe the stress concentration on the wires at the end fitting interface. The motivation of this work relies on the lack of detailed information of the stress and strain to which wires are subjected at the interface with the end fitting, as well as the importance of these in vital components for offshore oil exploration.

Este trabalho foca a avaliação da vida em fadiga de um novo modelo de terminal conector para dutos flexíveis (risers) de camadas não aderentes (unbonded). Os ensaios foram feitos levando em consideração apenas a parte estrutural desses dutos, de forma a ensaiar uma nova configuração de ancoragem da armadura de tração encontrada nesse equipamento conhecido como terminal conector (end fitting). É dentro deste componente que os arames da armadura de tração são fixados por resina epóxi em conjunto com uma configuração específica permitindo dessa maneira a sustentação do duto flexível quando fixado a plataformas offshore. Para a escolha do novo modelo de ancoragem aqui proposto, além de se tomar como referência, fez-se também uma analogia aos modelos utilizados nas ancoragens das barras metálicas utilizadas em concreto protendido. Isto foi feito por entender que algumas características mecânicas da resina epóxi aproximam-se das do concreto. Para a definição do novo modelo de ancoragem, uma análise simplificada, utilizando o Método dos Elementos Finitos (MEF), foi feita em dois modelos de ancoragens recomendados na API RP 17B (2002) e utilizado por alguns fabricantes, no intuito de verificar as distribuições das tensões ao longo desses arames dentro do terminal conector quando envolto pela resina epóxi. Esta análise destacou as regiões ao longo dos arames onde havia concentrações das tensões. Utilizando-se dessas informações, foi desenvolvida uma nova configuração para o arame dentro da resina de maneira a minimizar esses concentradores de tensão, permitindo assim que o modelo de ancoragem proposto tenha um melhor desempenho em fadiga. Para tanto, as verificações desses modelos feitas através do MEF e validadas através de ensaios experimentais em escala reduzida, mostraram que o modelo proposto apresentou reduções do KT da ordem de 16,5% e das tensões na resina de 60% quando comparados aos outros dois modelos comerciais. Após essas avaliações protótipos do novo terminal conector foram confeccionados em escala real e montado a dois pedaços de duto flexível de 2,5" de diâmetro, compondo assim dois corpos de prova: o CP1 e o CP2, os quais foram submetidos a ensaios de tração estáticos e carregamentos dinâmicos. Nos ensaios o CP1 foi submetido a uma carga máxima em tração de 844 kN e após esse carregamento, a não evidência de ruptura nos arames da armadura de tração o levou para o ensaio de fadiga com cargas em tração variando entre 130 e 304 kN a uma freqüência de 1Hz para uma vida de 1.000.000 de ciclos de carga. O resultado desse ensaio mostrou a viabilidade do conceito, uma vez que se atingiu a 1.000.000 de ciclos de carga sem a ruptura de qualquer arame dentro do terminal conector, evidenciado através da dissecação. Para finalizar os trabalhos, um segundo corpo de prova (CP2) foi confeccionado, obedecendo as recomendações estipuladas na API RP 17B (2002). Ensaiado com os mesmos parâmetros do CP1, se conseguiu levá-lo a fase de Dano igual a 1. Ao final desse ensaio observaram-se a ruptura de alguns arames na região mediana sobre o duto flexível que unia os dois conectores. Já as dissecações não mostraram evidências de arames rompidos internamente aos conectores. / This work focuses on the evaluation of the fatigue of life in a new model of end fitting for unbounded flexible pipe (risers). The tests had been made taking in consideration only the structural part of these risers, in order to test a new configuration of anchorage of the tensile armor found in equipment known as an end fitting. It is inside of this component that the tensile armor wires are fixed by epoxy resin in the set with specific configuration in this way allowing the sustentation these flexible pipes when the fixed offshore platforms. For the choice of the new model of anchorage considered here, beyond the reference if taking an analogy to the models used in the anchorage dues ones of the metallic bars used in prestressed concrete. This was made by understanding that some mechanical characteristics of the epoxy resin are come close to the concrete. For the definition of the new model of anchorage, the simplified analysis, using the Finite Element Method (FEM), was made in two models of anchorage dues recommended in API RP 17B (2002) and used by some manufacturers, in intention to verify the distributions tensions along the wires within of the end fitting when wrapped for the epoxy resin. This analysis highlighted the wires throughout the regions where it had concentrations of the tensions. Using these information of itself, a new configuration for the wire inside of the way resin was developed to minimize these concentrators of tension as soon as, allowing anchorage of the considered model one has better performance in fatigue. For in such a way, the verifications of these models made through the FEM and validated through experimental tests in reduced scale, had shown that the considered model presented reductions of the KT of the order of 16.5% and stress in the resin of 60% when compared with the others two commercial models. After these evaluations archetypes of connecting the new end fitting had been confectioned in real scale and mounted two pieces of flexible pipe of 2.5" of diameter, thus composing test of two bodies: the CP1 and the CP2, which had been submitted the static tension tests and dynamic loads tests. In the tests the CP1 was submitted to tension in the maximum load of 844 kN and after this shipment, the evidence of rupture in the wires of armor did not take the tension it for the tests of fatigue in traction with loads varying between 130 and 304 kN to the frequency of 1Hz for a life of 1,000,000 cycles of load. The result of this test showed the viability of the concept, that if the team reached the inside of 1,000,000 load cycles without the rupture of any wire of the end fitting, evidenced through the dissection. To finish the works, the body of the test (CP2) it was confectioned, obeying to the recommendations stipulated in API RP 17B (2002). Tested with the same parameters of CP1, were taken to the stage Damage equal to 1. To the end of this test they had observed it rupture of some wires in the region on the medium flexible pipe that joined the two end fittings. Already the dissections had not shown evidence of broken internally wires to the end fittings.