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Strength mobilisation for geotechnical design & its application to bored pilesVardanega, Paul Joseph January 2012 (has links)
No description available.
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X-Ray Study of Mechanical Properties of TiN Thin Films Coated on Steel by Ion Beam Mixing MethodITO, Toshimasa, TANAKA, Keisuke, AKINIWA, Yoshiaki, ISHII, Takahiro, MIKI, Yasuhiro 01 1900 (has links)
No description available.
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[en] EVALUATION OF THE FIELD LATERAL STRESS OF OVERCONSOLIDATED CLAYS: LABORATORYTESTS IN A SOIL FROM THE GUABIROTUBA FORMATION / [es] EVALUACIÓN DE TENSIÓN LATERAL DEL CAMPO DE ARCILLAS SOBREADENSADAS ENSAYOS DE LABORATORIO CON UN SUELO DE LA FORMACIÓN GUABIROTUBA / [pt] AVALIAÇÃO DA TENSÃO LATERAL DE CAMPO DE ARGILAS SOBREADENSADAS: ENSAIOS DE LABORATÓRIO COM UM SOLO DA FORMAÇÃO GUABIROTUBAROBERTA BOMFIM BOSZCZOWSKI 27 September 2001 (has links)
[pt] A maioria dos métodos de laboratório disponível para a
avaliação das tensões horizontais in situ é aplicável
somente a solos normalmente adensados ou levemente
sobreadensados. A avaliação do estado de tensões efetivas
in situ de solos rijos sobreadensados e, conseqüentemente o
desempenho tensão-deformação desses solos, envolve um
considerável grau de incertezas devido à dificuldade na
determinação da tensão lateral de campo. Apresenta-se,
neste trabalho, resultados de um estudo experimental de
laboratório que teve por objetivo: obter informações de
compressibilidade do material e do comportamento tensão-
deformação em condições não drenadas, e avaliar a tensão
lateral efetiva in situ de um solo da Formação Guabirotuba,
que se situa na Bacia Sedimentar de Curitiba.
Propõe-se uma nova metodologia experimental para a
determinação da tensão lateral de campo, tendo em vista que
as metodologias apresentadas na literatura não são
adequadas para solos rijos e sobreadensados. Na primeira
fase deste estudo foram realizados ensaios de
caracterização completa, análise mineralógica e de
microscopia eletrônica. Após a caracterização física do
material, passou-se ao estudo do comportamento
tensãodeformação e resistência com a execução de ensaios
triaxiais e edométricos. Foram executados ensaios triaxiais
não drenados com corpos de prova adensados isotropicamente,
e ensaios de adensamento com velocidade constante de
deformação de um solo intacto da Formação Guabirotuba e de
um solo da mesma Formação, porém laterizado. O método
proposto para a avaliação da tensão lateral de campo está
baseado no conceito de superfícies de escoamento, ou seja,
a história de tensões de um solo está relacionada com seu
comportamento tensão-deformação-rigidez, e, portanto,
pode ser determinado através desta. Foram executados
ensaios triaxiais com trajetória de tensões controlada, de
acordo com a metodologia proposta, em amostras indeformadas
desta Formação. / [en] Most of the available laboratory methods for the evaluation
of the in situ horizontal stresses are usually applicable
only to normally consolidated or slightly overconsolidated
soils. The assessment of the in situ effective stresses
state of rigid, overconsolidated soils, and consequently of
their stress-strain performance , involves a considerable
degree of uncertainty due to the difficulty in the
determination of the field lateral stresses . This thesis
presents the results of an experimental study performed in
the laboratory to gather information on compressibility and
undrained stress-strain characteristics, and to determine
the in situ effective lateral stress of a soil from the
Guabirotuba Formation, at the Curitiba Sedimentary Basin,
in the South of Brasil. The first stage of the study
comprised characterization tests, mineralogical analysis
and electronic microscopy evaluations. After the physical
characterization of the material, it was carried out the
study on the stress-strain-strength behaviour through
undrained triaxial tests and oedometric tests with constant
rate of deformation. Unweathred and latherized soil samples
from the Guabirotuba formation were used in such
investigations. As the methodologies presented in the
literature are not appropriate for rigid, overconsolidated
soils, a new experimental technique for the determination
of the in situ lateral stress was proposed. The proposed
method is based on the concept of yield surfaces. The
stress history of a soil is related to its stress-strain
behaviour and, therefore, can be inferred through monitoring
changes of the soil rigidity under a given stress path.
Following the proposed methodology, stress-path controlled
triaxial tests with internal measurement of axial strains
were performed in undisturbed samples of the Guabirotuba
Formation, providing an assessment of the field lateral
stress of the material. / [es] La mayoría de los métodos de laboratorio disponibles para la evaluación de las tensiones
horizontales in situ puede ser aplicado solamente a suelos normalmente adensados o levemente
sobreadensados. La evaluación del estado de tensiones efectivas in situ de suelos duros
sobreadensados y, consecuentemente el desempeño tensión deformación de esos suelos, involucra
un considerable grado de incertezas debido a la dificuldad en la determinación de la tensión lateral
de campo. En este trabajo se presentan resultados de un estudio experimental de laboratorio
realizado con el objetivo de obtener informaciones de compresibilidad del material y del
comportamiento tensión deformación en condiciones no
drenadas, y evaluar la tensión lateral efectiva in situ de un suelo de la Formación Guabirotuba,
situada en la Bacia Sedimentar de Curitiba. Se propone una nueva metodología experimental para
la determinación de la tensión lateral de campo, considerando que las metodologias presentadas en
la literatura no son adequadas para suelos duros y sobreadensados. En la primera fase de este estudio
fueron realizados ensayos de caracterización completa, análisis mineralógica y de microscopia
electrónica. Después la caracterización física del material, se pasó al estudio del comportamiento
tensión-deformación y resistencia con la ejecución de ensayos triaxiales y edométricos. Fueron
ejecutados ensayos triaxiales no drenados con cuerpos de prueba adensados isotrópicamente, y
ensayos de adensamento con velocidad constante de deformación de un suelo intacto de la
Formación Guabirotuba y de un suelo de la misma Formación, pero laterizado. El método propuesto
para la evaluación de la tensión lateral de campo está basado en el concepto de superfícies de
vaciado, o sea, la historía de tensiones de un suelo está relacionada con su comportamiento
tensión-deformación-rígidez, y, por tanto, puede ser determinado a través de ésta. Fueron ejecutados
ensayos triaxiales con trayectoria de tensiones controlada, de acuerdo con la metodología propuesta,
en muestras indeformadas de esta Formación.
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Avaliação experimental das relações tensão-deformação de um tecido de fibra de vidro recoberto com PTFE. / Experimental evaluation of the stress-strain relationships of a PTFE coated fiberglass fabric.Maurício Roberto de Pinho Chivante 16 October 2009 (has links)
Com o crescente uso de estruturas de membrana tensionada, as relações tensãodeformação do tecido utilizado em sua fabricação devem ser bem entendidas. Deste modo, esta dissertação apresenta um estudo sobre o comportamento mecânico de um tecido arquitetônico PTFE-vidro, ressaltando seu complexo mecanismo de deformação que engloba efeitos de anisotropia, não-linearidade física, troca de ondulações, histerese, remoção do espaçamento entre os fios e variação de temperatura. Diferentes métodos para modelagem do material foram estudados, com ênfase no modelo de material ortótropo representado por um funcional energia de deformação hiperelástico. Além disso, vários protocolos para ensaios de tração em tecidos recobertos foram analisados e uma série de ensaios biaxiais com amostras cruciformes foram realizados no Centro de Pesquisa e Desenvolvimento da Birdair, Inc. Um determinado funcional energia de deformação foi então ajustado aos dados de campo obtidos nestes testes, cujos resultados foram então comparados diretamente aos dados obtidos em campo e a um ajuste direto de uma superfície suave tensão-deformação. A performance do modelo ajustado não se encontra ainda em um patamar de aplicação industrial, entretanto este estudo permite um entendimento global dos mecanismos de deformação do tecido PTFEvidro, fornecendo também uma massa de dados consistentes que podem ser utilizados em situações práticas. / Considering the growing use of tensioned membrane structures, the stress-strain relation of the fabric used on its construction must be well understood. This dissertation presents a study of the mechanical behavior of a PTFE coated fiberglass fabric, emphasizing its complex strain mechanism which is influenced by the material anisotropy, physical non-linearity, crimp interchange, hysteresis, removal of yarn spacing and changes in temperature. Different material models were studied, focusing on an orthotropic material model represented by a hyperelastic strain energy function. Also, different test protocols were reviewed and a series of biaxial tests on cruciform samples were performed at the Birdair, Inc.s Research and Development Center. A strain energy function was adjusted to the collected data and than its results compared to the data itself and to another stress-strain function directly adjusted to the data. The performance of the strain-energy function chosen is not on a level of industrial application; however this study gives a global understanding of the PTFE coated fiberglass strain mechanism and also provides a consistent database that may be used on real situations.
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Molecular Simulation of Anisotropic Stress and Structure in polymersSrivastava, Prashant Kumar January 2014 (has links) (PDF)
This dissertation presents a numerical study using molecular dynamic simulations
that interrogates the polymer structure as it is strained continuously in time and correlates it with the stress developed in it. We investigate the role of external control variables such as temperature, strain-rate, chain length, and density. At temperatures higher than glass transition, stress anisotropy is reduced even though bond stretch is greater at higher temperatures. There is a significant increase in stress level with increasing density. At faster rates of loading stress anisotropy increases. Deformation is mostly due to bond stretch and bond bending rather than overall shape and size. Stress levels increase with longer chain length. Cross-linkers beyond a critical value of functionality cause increased constraint on the motion of monomers and uniaxial stress developed increases. Stacking of
chains also plays a dominant role in terms of excluded volume interactions. Low density, high temperature, low values of functionality of cross-linkers, and short chain length, facilitate chain uncoiling and chain slipping in crosslinked polymers. Uniaxial stress in linear polymers, on the other hand, is only mildly in uenced by temperature. Sinusoidal strain loading clearly reveals the viscoelastic nature of polymers. Internal structural parameters of
the chains such as bond length, bond angle show hysteresis during loading and unloading. However, parameters representing overall size and shape of chains do not display any hysteresis. Small size magnetic particles and their small volume fractions in polymers show no signi cant e ect of applied external magnetic eld on anisotropic stress. Stress increases with lowering temperature, increasing density, decreasing volume fraction of magnetic particles, and increasing chain length
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Deformačně napěťová analýza fixátoru dolní končetiny Poldi 7 / Stress - strain analysis of inferios limb with fixator type Poldi 7Pásek, Jiří January 2008 (has links)
This diploma thesis deals with stress-strain analysis of inferious limb fixator type Poldi VII and tibia, whereupon is applied. In work is discribed creation of a geometry model of fixator and tibia, her discretization, loading and solving. Tibia was load by torsional moment and his magnitude was 10Nm. Then was perform a numerical solution in FEM system ANSYS Workbench 11.0. Further was effect biomechanical study about osification of broken part. Tibia was load by force, which evokes upright standing on both limbs.
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Analýza napjatosti a pevnostní kontrola tělesa ventilu parní turbíny / Stress and strength analysis of steam turbine valveKořínek, Tomáš January 2018 (has links)
This diploma thesis deals with the determination of lifetime and computational modeling of stress strain states arising in the body of the steam turbine valve. Due to the high temperature of the inlet steam, the creep of the material which fundamentally affects its final lifetime is also considered in the calculation. The lifetime is evaluated by four different procedures using the finite element method via the ANSYS software. The results are compared at the end of this work. One of the chapters is focused on solving the problem of the creep in the ANSYS software environment.
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Navrhování konstrukcí vozovek pomocí dimenzačního programu Alize / Design of road constructions with the programme AlizeGrošek, Jiří January 2013 (has links)
This master’s thesis deals with the analysis of stress, fatigue and the assessment of frost effects in program ALIZE as it is prescribed in norm NFP 98-086 and comparing with the regulation TP 170 Designing roadways of roads and program LayEps.
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Deformačně napěťová analýza sanovaného druhého premoláru / Stress - strain analysis of save premolar toothSáblíková, Zdeňka January 2008 (has links)
This diploma thesis deals with stress-strain analysis of healthy and save tooth. Defor-mation and stress of tooth system with a part of jawbone was solved by calculating method, FEM in computing system ANSYS Workbench 11. Stress-strain analysis of save of tooth was performed in twenty-five ways describing various classes and sizes of cavity, filling material and model of connection between the filling and the tooth.
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Topologicko-geometrický návrh a deformačně-napjatostní analýza tvaru disku železničního kola pro různé provozní podmínky na základě analýz LELM / Topological-geometric design and stress-strain analysis of the railroad wheel disc shape for different operating conditions on the grounds of LEFMBrabenec, Ladislav January 2011 (has links)
The thesis deals with the behaviour of a cracked rail wheel. The aim was to perform the strain analysis of intact wheel as well as the fracture analysis of the primary direct cracked wheel. Solution includes an analysis of operating conditions, assessment of the substantiality of articular components of load, stiffness of the wheel, a comprehensive analysis of fracture of the selected railway wheel profile and optimization of the wheel shape depending on the matching fracture properties.
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