Este trabalho apresenta um estudo do processo de cromatização de arames galvanizados da Linha de Galvanização 2 da Gerdau Riograndense através do entendimento das variáveis de processo que podem ser alteradas com o intuito de proporcionar uma resistência à oxidação branca maior do que a fornecida com os parâmetros de processo utilizados atualmente. Amostras de arames foram coletadas diretamente da linha de galvanização e submetidas a ensaios acelerados de corrosão em câmaras de umidade saturada (NBR 8095 e ISO 6270-2)16 e de névoa salina (NBR 8094 e ASTM B 117)15. Com base nos resultados obtidos destes ensaios são propostas alterações nas variáveis de processo, como por exemplo, tempo de imersão no tanque de cromatizante, avaliando o aumento ou não do poder protetivo. Os resultados obtidos até agora mostraram que as configurações operacionais da Linha de Galvanização 2 não oferecem uma condição para a formação de uma camada protetora eficiente. Espera-se com este trabalho justificar junto à Empresa a necessidade de alteração de parâmetros de processo para que se consiga obter significativo aumento no poder protetivo conferido pelo cromatizante ao arame galvanizado, e assim, ter condições de disponibilizar ao mercado um produto com qualidade superior no que tange a resistência à oxidação branca. / This work presents a study about the chromatization process for galvanized steel wires in the Galvanizing Line 2 of the Gerdau Riograndense through the understanding of variables of the process that can be modified to provide a superior white corrosion resistance than the one which is provided actually. Samples of wires were collected directly from the galvanizing line and submitted to accelerated corrosion tests in the saturated humidity chamber (NBR 8095 and ISO 6270-2)16 and the salt spray chamber (NBR 8094 and ASTM B 117)15. Based in the results from this tests changes in the process variables are proposed like immersion time in the chromatizating bath to evaluate the increase or decrease of the protective action. The results obtained so far showed that the operational configurations of the Galvanizing Line 2 do not offer a good condition to create an efficient protective layer on the wire. The expectation of this work is to justify to the company that changes in the parameters process are necessaries to get a significant increasing of the protective chromatizating action on the galvanized wire and this way to have conditions to offer to costumers a product with superior quality about white corrosion resistance.

Through translations and transformations, my degree project aims to explore what makes something – space, or an object– charged. I am investigating ways to create objects with the starting point in two pieces of furniture, analyzing them both in their everyday contexts, and in certain works of art. This has resulted in the creation of two works that I have called an imprint and a bench and a bed. The quality that I have been searching for in this project is what activates a subjective feeling of recognition that will stay in the mind of the beholder, a charge in an object that affects memory or consciousness. The way I explore this quality is by analyzing the terms Eros and punctum and by investigating the relationship between the abstract and the figurative, examining the bodily connection to the objects and the surrounding.

Yes / In this study, the enhancement of stainless steel wires (SSWs) to the flexural fatigue performance of reactive powder concrete (RPC) including fatigue life and fatigue stress-strain hysteresis relationship as well as fatigue damage were investigated, and the underlying mechanisms were explored through microstructure observation and characteristic analyses of hydration products. The average flexural fatigue life of RPC is increased by 636.6%, 558.3% and 1010.7% at the maximum stress levels of 0.7, 0.8 and 0.9 when 1.5 vol.% SSWs are incorporated. The method of moments and method of maximum likelihood are employed to calculate the scale and shape parameters for fatigue life subscribed to Weibull distribution. The calculated ratio of flexural fatigue endurance limit to static flexural strength for SSWs reinforced RPC reaches up to 0.64. The incorporation of SSWs decreases the flexural failure damage of RPC by 41.5% and converts the long and link-up micro cracks into emission cracks centered on SSWs. Benefited from the large specific surface area of SSWs, abound of silica fume with pozzolanic activity absorbs on the surface of SSWs and continues to hydrate, reducing the surrounding water-binder ratio to form a microstructure enhancement zone with SSWs as the core and improve the homogeneity of RPC. This can be confirmed by the decrease of porosity, Ca(OH)2 crystal orientation index and molar ratio of CaO to SiO2 for calcium silicate hydrate gels. SSWs can also enhance the fatigue performance of RPC by transmitting hydration heat, inhibiting the initiation and propagation of micro cracks especially at the initial stage of fatigue load, bridging cracks and being pulled-off. The excellent flexural fatigue properties and homogeneous microstructures of SSWs reinforced RPC make it particularly suitable for large-span and ultra-thin elements in extreme service environments.

Elektromagnetisk provning (ECT) har blivit en av de mest använda metoderna för attkvalitetssäkra produkter där icke-destruktiv testning av material krävs. Vid provning av ståltrådinteragerar utrustningen med det testade materialet och upptäcker ytdefekter och, i vissomfattning, om strukturen skiljer sig från det kalibrerade provet. Om produkten befinner sigutanför specifikationen, skrotas den eller ombearbetas. Denna Mastersuppsats undersökerkalibreringsförfarandet för elektromagnetisk provning som utförs av Suzuki Garphyttan, som är enav de största tillverkarna i världen av ventil- och transmissionsfjädrar för bilindustrin. Genom deslutsatser som framgår av denna rapport, som baseras på undersökningar gjorda i vetenskapligaartiklar och genom att analysera den data som inhämtats från produktionen, presenteras enstandardisering av kalibreringsförfarandet. Detta är nödvändigt för att säkerställa såväl testernastillförlitlighet, såväl som minimering av risken för att skrota ut material på grund av felaktigainställningar, till exempel på grund av otillräckligt signal-brus (S/N)-förhållande. Fokus ligger påsond-baserad, roterande testning, i denna avhandling kallad circografen, eftersom den är manuelltkalibrerad.Några av de konstaterade resultaten i rapporten är:● Standard Operating Procedures (SOP)-baserade instruktioner implementeras i företagetskvalitetssystem. Detta för att minska variationer i kvalitet mellan olika operatörer ochmaskiner.● Ett förslag på intervaller för värden (fasvinkel, förstärkning, korrigering av filter och såvidare) presenteras. Detta är baserat på insamlad unik produktionsdata från operatöreroch utförda test.● Fasvinklarna som används varierar inom specifika intervaller och bestäms av materialval iallmänhet och frekvensval i synnerhet.● Konduktivitets- och permeabilitetsvärdena för oljehärdad tråd, liksom penetrationsdjupetför tre olika frekvenser presenteras.● Härdningsfel kan inte detekteras i roterande provning● Ökat kolinnehåll minskar den elektriska ledningsförmågan och ger ökad resistivitet, vilketgör att fasen flyttar sig och resulterar i ett minskande gap mellan brussignal ochspricksignal. / Eddy current testing (ECT) has become one of the most extensively used methods to secure theproducts and constructions when non-destructive testing is required. In typical cases of steel wiretesting, the equipment interacts with the tested material and discovers surface defects and, to alimited extent, if the inner structure is differing from the calibration sample. If the product isfound to be outside specification, it is either scrapped or reworked. This master thesis investigatesthe Eddy current testing calibration procedures performed by steel wire manufacturer SuzukiGarphyttan, which is one of the largest producers in the world of valve and transmission springwire for the automotive industry. By the research shown in this thesis, based on the investigationmade in scientific papers and by analyzing data extracted from production, a standardization ofthe calibration procedure is being presented. This is to secure both the testing reliability, andminimizing the risk of scrapping material due to inaccurate settings, for example due toinsufficient signal to noise (S/N) ratio. The focus is on probe-based, rotating testing, in this thesiscalled the circograph, since it is manually calibrated.Some of the findings established in the report: Standard Operating Procedures (SOP) based instructions is being implemented in thecompany's Quality system. This is to decrease the process variations between differentoperators and machines. Suggestions of intervals for values (Phase angle, gain, filter correction and so forth) arepresented. These values are based on collected unique production data from operators andmachines, as well as performed tests. The phase angles used are ranging between specific value intervals, and set by materialchoice in general and choice of frequency in particular. The conductivity and permeability values for oil-tempered wire, as well as penetrationdepth for three different frequencies, are presented. Hardening error cannot be detected in the circograph. Increased carbon content is decreasing conductivity and increasing resistivity, causing thephase to move slightly and decreasing the gap between noise signal and crack signal.

This master thesis deals with calculation of steel wire ropes for cranes. Concretely is acted about calculation of wire ropes overhead crane manufactured by KRÁLOVOPOLSKÁ a.s. designed for load capacities up to 25 000 kg, which is situated at hall of steelworks. Further, the calculation of wire ropes different overhead crane was made to compare the results. The solution includes calculation made using valid standards ČSN 27 0100, DIN 15020-1, FEM 1.001 and ČSN EN 13001-3-2. Finally, the procedures are evaluated and compared with each other.

Les matériaux architecturés attirent de plus en plus d’attentions de par leur capacité à combiner différentes propriétés ciblées. Dans ce contexte, les matériaux enchevêtrés, et plus particulièrement les matériaux monofilamentaires enchevêtrés, présentent des propriétés intéressantes en terme de légèreté, de ductilité, et de facteur de perte. En raison de l’architecture interne complexe de ces matériaux, leur caractérisation et la compréhension des mécanismes de déformation nécessitent une méthodologie adaptée. Dans cette étude, l’enchevêtrement est réalisé manuellement pour différents fils d’acier et soumis à une compression oedométrique. De manière à étudier le comportement sous charge de ce type de matériaux, un dispositif de compression uniaxiale guidée a été mis en place dans le tomographe. Il est ainsi possible de suivre, à l’aide de mesures quantitatives, la déformation de l’échantillon et l’évolution du nombre de contacts pour différentes fraction volumiques. L’utilisation de ces données microstructurales a permis un meilleure compréhension du comportement mécanique de tels enchevêtrements. Une rigidité pouvant varier de 20 à 200 MPa en fonction des paramètres de mise en forme (diamètre et forme du fil, fraction volumique, matériau constitutif) a été déterminé. Un matériau homogène de rigidité plus faible a pu être obtenu en pré-déformant le fil sous forme de ressort avant enchevêtrement. Le facteur de perte du matériau a ensuite été mesuré à la fois sous chargement statique et dynamique. L’analyse mécanique dynamique a mis en évidence la capacité de ce matériau à absorber de l’énergie avec une valeur de facteur de perte d’environ 0.25. Les propriétés mécaniques du matériau ont tout d’abord été modélisées analytiquement par un modèle de poutres et un bon accord avec les résultats expérimentaux a pu être obtenu en définissant un paramètre d’orientation equivalent, spécifique à la compression oedométrique de matériaux enchevêtrés. En parallèle, un modéle éléments discrets a été developé afin de simuler le comportement en compression de matériaux monofilamentaires enchevêtrés. Ce modèle s’appuie sur une discrétisation du fil en éléments sphériques, acquise à partir de données de tomographie. Bien que seul le comportement élastique du fil constitutif ait été pris en compte, une bonne adéquation entre résultats numériques et expérimentaux a été obtenu en ajustant les coefficients de frottement du modèle. / Playing with the architecture of a material is a clever way of tailoring its properties for multi-functional applications. A lot of research have been made, in the past few years, on what is now referred to as “architectured materials” (metal foams, entangled materials, steel wool, etc), mostly for their capacity to be engineered in order to present specific properties, inherent to their architecture. In this context, some studies have been carried out concerning entangled materials but only a few on monofilament entangled materials. Such a material, with no filament ends, could exhibit interesting properties for shock absorption, vibration damping and ductility. In this study, entanglements were manually produced, using different types of wire, and submitted to constrained (inside a PTFE die) in-situ compressive tests within the laboratory tomograph. This technique enabled a 3D, non destructive, microstructural characterization of the complex architecture of these materials, along with the analysis of their macroscopic mechanical properties. The stiffness of this material was found to be in a 20-200 MPa range and homogeneous samples could be obtained, while lowering their stiffness, by pre-deforming the initial wire as a spring. Damping measurements were performed using different types of entanglements (constitutive materials, volume fraction, wire diameter, wire shape) under both monotonic and dynamic loadings and directly linked to the measurements of the number of contacts. The Dynamic Mechanical Analysis underlined the great capacity of this material to absorb energy with a loss factor of about 0.25 and damping was found to decrease with the stiffness of the entanglement. The mechanical properties of this material were first modeled using an analytical “beam” model based on the experimental evolution of the mean distance between contacts and a good agreement was found with the experimental results. In parallel, a Discrete Element Method was used in order to model the compressive behaviour of Monofilament Entangled Materials. Although purely elastic properties were taken into account in the model, a very good agreement with the experimental results was obtained by adjusting the friction coefficients of the model. This tends to prove that the plasticity of these entangled materials is rather due to the structure (friction) than to the constitutive material itself.

Natural fiber-reinforced composites are now finding extensive uses in various fields from household articles to automobiles. These composites can score high compared to common synthetic fiber-based composites, notably glass fiber-reinforced composites, in areas such as occupational safety and health, and impact on environment. The current research work is motivated by the need for exploring jute fibers as replacement for glass fibers for various engineering design applications including more demanding impact protection applications as in automotive body structures. In the current work, detailed mechanical characterization of jute-polyester (JP) composite laminates till failure has been carried out for tensile, compressive and flexural loads by varying volume fraction of jute fibers. The effect of fiber volume fraction on mechanical properties is shown. Because of the potency of closed thin-walled components as structural energy-absorbers, a comprehensive experimental study has been performed, for the first time, comparing the behaviors of various geometric sections of JP and glass-polyester (GP) composite tubes under axial quasi-static and low velocity impact loading. Additionally, for jute-reinforced plastic panels to be feasible solutions for applications such as automotive interior trim panels, laminates made of such materials should have adequate perforation resistance. Thus, a detailed comparative study has been carried out for assessing the performance of JP laminates vis-a-vis GP plates under low velocity impact perforation conditions. As high-end product design is heavily driven by CAE (Computer-Aided Engineering), the current research work has also focused on the challenging task of developing reliable modeling procedures for explicit finite element analysis using LS-DYNA for predicting load-displacement responses and failures of JP composites under quasi-static and impact loading conditions. In order to extend the applications of JP composites to structurally demanding applications, hybrid laminates made of jute-steel composites and jute with nanoclay-reinforced polyester have been investigated and the considerable enhancement of mechanical properties due to hybridization is shown. Furthermore, a comprehensive study has been conducted on the behavior of JP laminates for varying degrees of moisture content until saturation, and the efficacy of hybrid laminates in this context has been shown.