In diesem Beitrag werden ein Berechnungsverfahren und ein Bemessungskonzept für biegebeanspruchte textilbetonverstärkte Stahlbetonbauteile vorgestellt. Ihre Anwendbarkeit wird durch die Auswertung von Versuchen an verstärkten Stahlbetonplatten mit einer Reihe veränderlicher Ausgangswerte überprüft. Als Ergebnis dieser Arbeit stehen dem Anwender einfach nutzbare, praxisgerechte Bemessungstabellen zur Verfügung. / This article introduces a calculation method and a design concept for reinforced concrete elements strengthened with textile concrete. Its applicability is verified by an analysis of tests with strengthened steel reinforced concrete slabs with a certain variety of design parameters. Results of this work are easy manageable, praxis-orientated design tables that are available for users.

No description available.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2010.

Made available in DSpace on 2014-06-11T19:25:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-02-14Bitstream added on 2014-06-13T19:12:02Z : No. of bitstreams: 1 alcantarasegundinho_pg_me_ilha.pdf: 4485630 bytes, checksum: 0e58733013f71fa0d93bb68c2fdabebb (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O estudo em estruturas mistas é dedicado ao emprego do material madeira-concreto em estruturas de pontes, mais precisamente no seu tabuleiro. No entanto, a aplicação desse material no Brasil não está regulamentada por normas que permitam ao engenheiro civil fazer sua aplicação nas estruturas correntes. Com a proposta de viabilizar o uso desse material madeira-concreto esse estudo vem contribuir com um melhor entendimento do comportamento físico da ligação entre os materiais madeira e concreto. O estudo dessa ligação foi realizado quantificando o módulo de deslizamento em corpos-de-prova do tipo push-out, vigas T e tabuleiro de madeira-concreto. Os resultados experimentais do módulo de deslizamento obtidos por esses três tipos de ensaios foram comparados com os resultados obtidos teoricamente pelo Eurocode 5 (1993). Também, no seguinte estudo foi feito uma simulação numérica do tabuleiro de madeira-concreto usando um programa para análise estrutural baseado no Método dos Elementos Finitos (MEF). Na conclusão dessa pesquisa verificou-se que o comportamento estrutural desse material misto pode-ser calculado usando o Eurocode 5 (1993) e o Método dos Elementos Finitos (MEF). / The study of mixed structures is dedicated to the use of timber-concrete material in bridges' structures, more precisely in its tray. However, the application of this material in Brazil is not regulated by standards that allow the civil engineer to make its application in the current structures. With the proposal to make possible the use of this timber-concrete material this study contributes to understand better the physical behavior of the linking between wood and concrete. The study of this connection was carried through quantifying the slip's module in specimens of push-out type, T beams and timber-concrete's tray. The experimental results of the slip's module from these three kinds of tests had been compared with the results obtained theoretically for Eurocode 5 (1993). Also, in the following study it was made a mathematical simulation of the wood-concrete's tray using a numerical analysis' program based on the Finite Elements' Method (MEF). In the conclusion of this research it was verified that the structural behavior of this mixed material can to be calculated using Eurocode 5 (1993) and the Method of the Finite Elements (MEF).

Foi realizado estudo sobre a influência da variação de alguns parâmetros do tratamento térmico de têmpera e revenimento, bem como aplicação de criogenia, na tenacidade a fratura do aço aeronáutico 300M, com a utilização da técnica de corpo cilíndrico com entalhe. Primeiramente, realizou-se a construção da curva de transição dúctil frágil, através de ensaio Charpy, para amostras submetidas a três tratamentos térmicos, 1 - Têmpera seguida de Revenimento, 2 - Têmpera seguida de criogenia e revenimento. Não foi observada influência significativa da aplicação da criogenia (tratamento de numero 2) na curva de transição dúctil-frágil em comparação com o tratamento térmico número 1. Em um segundo momento, com o auxílio da técnica de ensaio de corpo cilíndrico com entalhe, realizou-se a medição da tenacidade à fratura das amostras do aço 300M submetido a quatro diferentes tratamento térmicos, Q, V, C e D. Os tratamentos variavam entre si principalmente pela temperatura de austenitização. Os valores de dureza para as amostras submetidas a criogenia (V e D) foram maiores que as dos tratamentos sem criogenia (Q e C), e também apresentaram tenacidade à fratura menor. Com relação à temperatura de austenitização, observou-se que os tratamentos C e D, austenitizados a 980°C, propiciaram a completa dissolução de precipitados primários da matriz, elevando a tenacidade à fratura com relação aos tratamentos realizados na faixa de 870°C, Q e V, superando também os efeitos negativos para a tenacidade à fratura devido ao aumento no tamanho de grão. / This work studies the influence of the variation for some parameters on quenching and tempering heat treatment, and also deep cryogenic application, on aeronautic steel 300M fracture toughness. First, the ductile-brittle curve was constructed, by Charpy test, for samples submitted for three heat treatments, 1 Quenching and Tempering, 2 Quenching, deep cryogenic and tempering. No significant influence of deep cryogenic treatment addition (heat treatment 2) on ductile-brittle curve was observed in comparison with heat treatment 1. After that, the fracture toughness for 300M steel, submitted for heat treatments Q, V, C e D, was measured using circumferentially notched specimens technique. The main difference among these heat treatments is about austenitizing temperature. For heat treatments with deep cryogenic treatment (V and D), the hardness values were bigger than the ones without this and, analyzing fracture toughness, it was lower than the treatments without cryogenic treatment. Regarding austenitizing temperature, all heat treatments with higher austenitizing temperature at 980°C (C and D), allows complete dissolution of carbides and prior precipitates particles. Its effect was observed that this characteristic increase the fracture toughness when it is compared with others heat treatments with lower austenitizing temperature at 870°C (Q and V). This improvement is enough to overcome the grain size grown negative effects for fracture toughness.

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Background. In today's industry, sheet metal forming is widely used for manufacturing products. Knowledge about the behaviour of sheet metal is crucial to avoid phenomena that negatively impact the manufactured components. Extensive research has been conducted to capture aspects of this behaviour, such as plastic anisotropy and strain hardening. Mathematical models have been proposed to describe these phenomena, typically requiring material-specific constants for improved accuracy. These models are important as they are leveraged in finite element simulations which are essential for the sheet metal industry. However, conventional methods for identifying these constants often require multiple tests and time-consuming calibration. Aim and Objectives. The aim of this thesis is to improve the efficiency of the material identification procedure of anisotropy and hardening by using a novel test specimen. To achieve the aim, the objectives include designing a test specimen, proposing an identification methodology and to compare the efficiency with existing identification techniques. Method. Two studies were conducted, a numerical study and an experimental study. In the experimental study, experimental data was used as target data in the optimization, while the numerical study utilized data from a finite element simulation with reference parameters as target data. A novel specimen geometry was designed by combining one plane-strain and two shear test specimens to cover multiple strain states. The inverse identification technique finite element model updating method was chosen for both studies. Additionally, the plastic anisotropy was modelled by using the YLD2000-2D yield function and the strain hardening was modelled by using Swift's hardening law. Result and Discussion. The identified parameters in the numerical study show discrepancies, but the identification errors are comparable to similar studies. During the verification, the identified parameters were mostly able to capture the reference behaviour. In the experimental study, the identified parameters showed significant deviations during the verification which may stem from factors such as geometric deviations, noise in data and phenomena such as twisting and bending in the physical test not being captured by the simulation models. Conclusions. The efficiency of determining the anisotropy parameters and the hardening parameters was improved when utilizing the proposed methodology and test specimen. The proposed methodology requires one less experimental test compared to the conventional identification method and does not require further calibration to determine both the anisotropy and hardening parameters compared to related studies. / Bakgrund. I dagens industri så är plåtformning använd i stor utsträckning för att tillverka produkter. Kunskap om beteendet av plåt är väsentligt för att undvika fenomen som negativt påverkar de tillverkade komponenterna. Omfattande forskning har utförts för att fånga olika aspekter av detta beteende, som plastisk anisotropi och deformationshärdning. Matematiska modeller har blivit föreslagna för att beskriva dessa fenomen, som typiskt kräver material-specifika konstanter för förbättrad noggrannhet. Dessa modeller är viktiga eftersom de är använda i finita element simulationer som är väsentliga för plåtformningsindustrin. Dock så behöver konventionella metoder för att identifiera dessa konstanter ofta flera tester och tidskonsumerande kalibrering. Syfte och Målen. Syftet med detta examensarbete är att förbättra effektiviteten för materialidentifieringsproceduren för anisotropi och härdning genom att använda en ny testbit. För att uppnå syftet så inkluderar målen att konstruera en testbit, föreslå en identifieringsmetodik och att jämföra effektiviteten med existerande identifieringstekniker. Metod. Två studier var utförda, en numerisk studie och en experimentell studie. I den experimentella studien så användes experimentell data som måldata i optimeringen, medan den numeriska studien använde data från en finita element simulation med referensparametrar som måldata. En ny testbit var konstruerad genom att kombinera en plan-töjning och två skjuvnings-testbitar för att täcka flera töjningstillstånd. Invers-identifieringstekniken finita-element-modell-uppdatterings metoden val-des för båda studierna. Den plastiska anisotropin var modellerad genom användning av YLD2000-2D flytfunktionen och deformationshärdningen var modellerad genom Swifts härdningslag. Resultat och Diskussion. De identifierade parametrarna i numeriska studien visar skiljaktigheter, men identifieringsfelen är jämförbara med liknande studier. Under verifieringen så kunde de identifierade parametrarna mestadels fånga referensbeteendet. I den experimentella studien så visades signifikanta avvikelser under verifieringen, som kan bero på faktorer som geometriska avvikelser, brus i datan och att fenomen som vridning och böjning i det fysiska testet inte kunde fångas av simulationsmodellerna. Slutsatser. Effektiviteten för bestämningen av anisotropi parametrarna och härdnings parametrarna var förbättrad genom att använda den föreslagna metodiken och testbiten. Den föreslagna metodiken behöver ett färre experimentellt test jämfört med den konventionella identifieringsmetoden och behöver inte vidare kalibrering för att bestämma både anisotropi och härdningsparametrarna, jämfört med relaterade studier.

[pt] Frequentemente enfrenta-se grandes desafios na recuperação de amostras intactas de rejeitos com matrizes mais arenosas para a realização de ensaios laboratoriais. Essas dificuldades muitas vezes limitam a caracterização desses materiais ao uso de amostras reconstituídas, cuja capacidade de reproduzir o comportamento in-situ dos rejeitos está inerentemente ligada à capacidade do método de preparação da amostra de reproduzir a matriz do material. Vários estudos demostraram que o comportamento de rejeitos arenosos sob pequenas e grandes deformações são afetados pelos métodos empregados para preparação das amostras e o presente estudo busca entender de que forma a microestrutura pode interferir em tais variações. Buscando aprofundar nesta temática, a pesquisa objetivou realizar ensaios de caracterização física, química, mineralógica e microestrutural de uma amostra de rejeito de minério de ferro filtrado, predominantemente arenoso, testando três técnicas de reconstituição de amostra: Compactação com soquete (Moist tamping, MT), Pluviação úmida (Water pluviation, WP) e Deposição de lama (Slurry deposition, SD), avaliando a alteração na resposta da microestrutura do material frente às diferentes técnicas de moldagem. Foram realizados ensaios de análise de microtomografia computadorizada de raios X do material preparado com distintos índices de vazios, sendo: 0,70, 0,75 e 0,80. Ao final de cada preparação, as amostras foram submetidas ao congelamento instantâneo com o uso de nitrogênio líquido. De posse dos resultados, observou-se variações significativas entre os métodos de preparação de amostras do estudo, no que tange à disposição das partículas no meio, espaços vazios (porosidade) e influência da saturação do corpo de prova. Os resultados obtidos dos ensaios de microtomografia computadorizada indicaram arranjo desorientado e macroporoso entre as técnicas de reconstituição de amostras, observando-se similaridade microestrutural entre as técnicas MT e WP, tanto por constatação visual quanto por avaliação dos atributos microestruturais. A técnica de MT tende a formar grumos durante o processo de compactação com soquete, formando uma estrutura tida como favo de mel, podendo simular bem o empilhamento de rejeitos compactados. Já a técnica WP, devido ao seu processo de sedimentação natural, também tende a formar espaços vazios devido ao arranjo das partículas, sendo mais susceptível a sofrer segregação. Apesar disso, a técnica WP também pode ser aplicável para depósitos hidráulicos devido ao processo de sedimentação natural sem esforço de compactação. Já a técnica SD produz uma matriz de rejeito específica, influenciada pelo processo de homogeneização. Essa uniformidade das amostras observada na técnica SD pode representar bem depósitos hidráulicos, a depender das condições de lançamento de rejeito. Ademais, a pesquisa buscou avaliar a microestrutura de um rejeito de minério de ferro através da matriz gerada por cada técnica de reconstituição de amostras, identificando os aspectos que podem influenciar no arranjo e distribuição dos grãos no meio e macroporosidade. O congelamento instantâneo pode preservar as características das amostras, porém cada técnica possui suas limitações e individualidades as quais foram abordadas neste trabalho, e devem ser utilizadas com cautela para definição da técnica a ser adotada em função da condição do rejeito in-situ para fins de comparação. / [en] Great challenges are often faced in recovering intact samples from tailings with sandier matrices for carrying out laboratory tests. These difficulties often limit the characterization of these materials to the use of reconstituted samples, whose ability to reproduce the in-situ behavior of the tailings is inherently linked to the ability of the sample preparation method to reproduce the material matrix. Several studies have demonstrated that the behavior of sandy tailings under lows and highs deformations are affected by the methods used to prepare the samples and the present study seeks to understand how the microstructure can interfere with such variations. Seeking to delve deeper into this topic, the research aimed to carry out physical, chemical, mineralogical and microstructural characterization tests of a sample of filtered iron ore waste, predominantly sandy, testing three sample reconstitution techniques: Moist tamping (MT), Water pluviation (WP) and Slurry deposition (SD), evaluating the change in the response of the material s microstructure to different molding techniques. X-ray computed microtomography analysis tests were carried out on the prepared material with different void indices, being: 0.70, 0.75 and 0.80. At the end of each preparation, the samples were subjected to instant freezing using liquid nitrogen. With the results in hand, significant variations were observed between the study sample preparation methods, regarding the arrangement of particles in the medium, empty spaces (porosity) and the influence of the saturation of the specimen. The results obtained from microcomputed tomography tests indicated a disoriented and macroporous arrangement between the sample reconstitution techniques, observing microstructural similarity between the MT and WP techniques, both by visual observation and by evaluation of microstructural attributes. The MT technique tends to form lumps during the socket compaction process, forming a structure known as a honeycomb, which can well simulate the stacking of compacted waste. The WP technique, due to its natural sedimentation process, also tends to form voids due to the arrangement of the particles, being more susceptible to segregation. Despite this, the WP technique can also be applicable for hydraulic deposits due to the natural sedimentation process without compaction effort. The SD technique produces a specific waste matrix, influenced by the homogenization process. This uniformity of the samples observed in the SD technique may well represent hydraulic deposits, depending on the waste disposal conditions. Finally, the research sought to evaluate the microstructure of an iron ore tailings through the matrix generated by each sample reconstitution technique, identifying aspects that can influence the arrangement and distribution of grains in the environment and macroporosity. Instant freezing can preserve the characteristics of the samples; however each technique has its limitations and individualities, which were addressed in this work, and must be used with caution to define the technique to be adopted depending on the condition of the in-situ waste for the purpose of comparison.

The unique thermo-mechanical behavior of Shape Memory Alloys (SMAs), such as their ability to recover the original shape upon heating or being able to tolerate large deformations without undergoing plastic transformations, makes them a good choice for actuators. This work studies their application in the aerospace and defense industries where SMA components can serve as release mechanisms for gates of enclosures that have to be deployed remotely. This work provides a novel approach in evaluating the stress and heat induced change of phase in a SMA, in terms of the transformation strain tensor. In particular, the FEA tool ANSYS has been used to perform a 2-D analysis of a Cu-Al-Zn-Mn SMA specimen undergoing a nontraditional loading path in two steps with stress and heating loads. In the first load step, tensile displacement is applied, followed by the second load step in which the specimen is heated while the end displacements are held constant. A number of geometric configurations are examined under the two step loading path. Strain results are used to calculate transformation strain which provides a quantitative measure of phase at a material point; when transformation strain is zero, the material point is either twinned martensite, or austenite depending on the temperature. Transformation strain value of unity corresponds to detwinned martensite. A value between zero and one indicates mixed phase. In this study, through two step loading in conjunction with transformation strain calculations, a method for mapping transient non-uniform distribution of phases in an SMA is introduced. Ability to obtain drastically different phase distributions under same loading path by modifying the geometry is demonstrated. The failure behavior of SMAs can be designed such that the load level the crack initiates and the path it propagates can be customized.

What if every craving that you ever felt stayed with you forever? Suppose facades couldn’t exist, and what should only be the deepest, densest core of a desire was formed into a mass, a body. Its will matching yours in its physical presence. I make creatures that are embodiments of emotions. In this study I mainly focus on desires and inhibitions surrounding romance. I explore anatomical structures and how material make-up can directly reflect emotional character. In this exploration, the materiality of clay allows for a thorough manipulation of the composition of the creatures. In this I am also able to manipulate the material properties of clay to reflect states of existential discomfort, pushing the limits of material structure and stability. The final presentation of these creatures are as specimens of inhibitions, drawing in the viewer with empathy and repulsion as a fantastic other.