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Reid, Richard A. "Triaxial permeability device." Thesis, Georgia Institute of Technology, 1987. http://hdl.handle.net/1853/20036.
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Bonamigo, Mario. "Triaxial galaxy clusters." Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4717/document.
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Il est bien établit théoriquement et observationnellement que les amas de galaxies ne sont pas des objets sphèriques, et qu'ils sont beaucoup mieux décrits par la géométrie triaxiale. Malgré cela, les travaux sur la forme tri-dimensionnelle des amas de galaxies sont encore trés rares. L'objet de cette thèse est de contribuer à cette problématique naissante. L'originalité de ce travail est d'aborder ce sujet théoriquement et observationnellement. J'ai mesuré la forme d'amas de galaxies simulés, proposant des prédictions sur la forme des haloes de matière noire. J'ai ensuite développé un algorithme qui se propose de combiner des données en lentilles gravitationnelles et en rayons X afin de contraindre un modèle de haloe triaxial. L'algorithme est testé sur des données simulées. Finalement, je présente l'analyse en rayons X de Abell 1703, qui, combinée avec l'analyse en lentilles gravitationnelles, permettra de déterminer la forme de Abell 1703It is well established both theoretically and observationally that galaxy clusters are not spherical objects and that they are much better approximated as triaxial objects. This thesis focusses on the three dimencional shape of galaxy clusters. The originality of my approach is to tackle the problem both theoretically and observationally. First, I have measured the shape of dark matter haloes in the Millenium XXL and Sbarbine simulations, providing predictions for dark matter halo shape over 5 order in magnitude in mass. Then, I have developed an algorithm aimed at fitting simultaneously lensing and X-ray data in order to constrain a triaxial mass distribution. The algorithm is tested and characterized on mock data sets. It is found to be able to recover the input parameters. Finally, I present the X-ray analysis of galaxy cluster Abell 1703, which will be combined with the existing lensing analysis in order to investigate its shape
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El-Hage, Hassan M. "Digital triaxial testing system: Implementation of the digital triaxial testing system." Thesis, University of Ottawa (Canada), 1986. http://hdl.handle.net/10393/10673.
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MORIKAWA, SERGIO RICARDO KOKAY. "TRIAXIAL BRAGG GRATING ACCELEROMETER." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2004. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=5413@1.
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AGÊNCIA NACIONAL DE PETRÓLEOTRANSMISSÃO DE ENERGIA ELÉTRICA S.A
Desde o final da década de 80 a indústria de fibras óticas têm passado por avanços consideráveis. Através de técnicas controladas, as fibras ópticas podem gerar sinais associados a uma vasta gama de grandezas físicas funcionando como sensores denominados de Sensores a Fibra Óptica (SFO s). Diversas técnicas podem ser empregadas para tal, e entre as existentes a baseada em redes de Bragg é a que mais tem se destacado. O interesse por transdutores empregando esta técnica se justifica pelas vantagens proporcionadas pelo uso da luz, tais como sua capacidade de multiplexação, boa relação sinal/ruído, medições a longas distâncias, imunidade a campos eletromagnéticos, ausência de faísca, entre outras. Neste trabalho buscou-se desenvolver um transdutor e uma técnica de medição baseada em sensores a rede de Bragg para medição de vibrações mecânicas. Um acelerômetro óptico triaxial é projetado e construído. Diferentes modelos foram testados em busca das características de desempenho desejadas. Simulações numéricas empregando o método dos elementos finitos auxiliaram na decisão por melhores desenhos para o transdutor. Resultados de testes experimentais e calibrações empregando um sistema de aquisição de sinais desenvolvido são mostrados. Medições de longa duração para avaliação de estabilidade do sistema e efeitos de temperatura também são apresentados.
Since the end of the 1980s, the fiber optics industry has experienced considerable advances. Through a number of controlled techniques, fiber optics can generate signals associated with a vast array of physical measures, working as sensors denominated Optical Fiber Sensors (OFS s). Many different techniques can be employed to achieve this objective. Among these, the one based on Bragg networks has received the greatest amount of attention. The interest in transducers employing this technique is justified by the advantages of using light, such as its multiplexing capability, good signal-to-noise ratio, possibility of long distance measurements, immunity to electromagnetic fields, and absence of sparks. In the present work, a transducer and measurement technique based on Bragg network sensors vibration are developed, in order to measure mechanical vibrations. A triaxial optical accelerometer is designed and built. Different models are tested in the search for the desired performance characteristics. Numerical simulations employing the finite element method help the decision making process for better transducer designs. Results from experimental and calibration tests using a newly developed signal acquisition system are presented. Long duration measurements to evaluate system stability and temperature effects are also shown.
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Frauendorf, Stefan, and J. Meng. "Tilted Rotation of Triaxial Nuclei." Forschungszentrum Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-31369.
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The Tilted Axis Crankiug theory is applied to the model of two particles coupled to a triaxial rotor. Cornparirig with the exact quantal solutions, the interpretation and quality of the mean field approximations studied. Conditions are discussed when the axis of rotation lies inside or outside of the principal planes of the triaxial density distribution. The planar solutions represent ∆ I = 1 bands, whereas the aplanar solutions represent pairs of identical ∆ I = 1 bands with the same parity. The two bands differ by the chirality of the principal axes with respect to the angular momentum vector. The transition from planar to chiral solutions is evident in both the quantal and the mean field calculations. Its physical origin is discussed.
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Frauendorf, Stefan, M. Brack, and S. M. Reimann. "Triaxial shapes of sodium clusters." Forschungszentrum Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-32199.
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Frauendorf, Stefan, and J. Meng. "Tilted Rotation of Triaxial Nuclei." Forschungszentrum Rossendorf, 1996. https://hzdr.qucosa.de/id/qucosa%3A21963.
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The Tilted Axis Crankiug theory is applied to the model of two particles coupled to a triaxial rotor. Cornparirig with the exact quantal solutions, the interpretation and quality of the mean field approximations studied. Conditions are discussed when the axis of rotation lies inside or outside of the principal planes of the triaxial density distribution. The planar solutions represent ∆ I = 1 bands, whereas the aplanar solutions represent pairs of identical ∆ I = 1 bands with the same parity. The two bands differ by the chirality of the principal axes with respect to the angular momentum vector. The transition from planar to chiral solutions is evident in both the quantal and the mean field calculations. Its physical origin is discussed.
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Frauendorf, Stefan, M. Brack, and S. M. Reimann. "Triaxial shapes of sodium clusters." Forschungszentrum Rossendorf, 1995. https://hzdr.qucosa.de/id/qucosa%3A22046.
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Ourives, Licínia. "Ensaio triaxial cíclico em agregados." Master's thesis, Universidade de Évora, 2012. http://hdl.handle.net/10174/14864.
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Este trabalho teve como principal objetivo o estudo de um equipamento para realização do
ensaio triaxial cíclico. Trata-se de um ensaio que ainda não é realizado por empresas privadas,
muito embora sobre ele se tenham desenvolvido alguns trabalhos iniciais ao nível da
investigação. Neste trabalho pretende-se entender o funcionamento, limitações e capacidades
do equipamento para, posteriormente realizar o ensaio de modo sistemático.
Pôr a funcionar um equipamento totalmente desconhecido não foi tarefa fácil. Estudou-se o
seu funcionamento e, pela realização de múltiplos testes, foi possível detetar a existência de
falhas do equipamento que foram devidamente comunicadas ao fabricante, de modo a
possibilitar a sua correção.
Do mesmo modo, pela realização de pequenos ensaios, percebeu-se que seria melhor
construir peças novas, mais funcionais, para tornar o equipamento mais eficaz.
Tratando-se de um estágio, foi-me permitido ter um contacto muito próximo com o
funcionamento de um laboratório, executando ensaios de caracterização de solos e agregados,
a par da dedicação ao triaxial cíclico; ABSTRACT: The main objective of this work is to study the behavior of an equipment for triaxial cyclic
tests. This essay is not yet implemented by private companies, although they have developed
some initial research work. The study seeks to understand the functioning, limitations and
capabilities of the equipment to later systematic perform the test.
Operate totally an unknown equipment is not an easy task. By studying its functioning and
carrying out multiple tests, it was possible to detect the existence of equipment failures that
were communicated to the manufacturer, allowing their correction.
Similarly, performing small trials, it was realized that it would be better to make more
functional new components, to make the device more efficient.
The internship allowed having close contact with the laboratory operations by running soil and
aggregates characterization tests, simultaneously the realization of triaxial cyclic essay.
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LaVielle, Todd Hunter. "Liquefaction Susceptibility of Uncemented Calcareous Sands From Puerto Rico by Cyclic Triaxial Testing." Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/33044.
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Laboratory tests were performed to investigate the liquefaction susceptibility of uncemented calcareous sands. A series of isotropically consolidated undrained monotonic and cyclic triaxial tests were performed using the Playa Santa sand from Porto Rico. Playa Santa sand is a poorly graded calcareous clean beach sand composed of angular particles with large intra-granular voids. A series of consolidated undrained triaxial tests were performed with the Playa Santa sand remolded to a variety of relative densities and consolidated under a range of confining pressures. In addition, cyclic triaxial tests were performed at a confining pressure of 100 kPa and three sets of relative densities (20%, 40% and 60%). Generation of excess pore pressure under different levels of cyclic loading was established. As a result, relationships were developed to relate the number of cycles required for triggering of liquefaction to cyclic stress ratio. It was seen that the Playa Santa sand was less susceptible liquefaction than quartzitic sands of the same relative density remolded and tested under similar conditions.Master of Science
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QUARESMA, HELENA DAHIA. "CUBICAL TRIAXIAL TESTS IN SATURATED SAND." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1997. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=2068@1.
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CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOEste trabalho apresenta um estudo experimental detalhado do comportamento tensão-deformação-resistência de uma areia saturada submetida a uma condição tridimensional de carregamento. Os ensaios foram realizados nos equipamentos triaxiais cúbico e convencional. O equipamento triaxial cúbico apresenta a vantagem de controlar a magnitude das três tensões principais independentemente ( sigma 1 , sigma 2 , sigma 3 ) sob condições drenada e não drenada. Para o desenvolvimento do trabalho foi utilizada uma amostra de areia calcárea. Os corpos de prova utilizados foram moldados por pluviação submersa. No programa experimental foram realizados ensaios especiais, seguindo diferentes trajetórias de tensão. Este programa foi elaborado de modo a verificar a influência de cada parâmetro de tensão individualmente e os efeitos da anisotropia inicial de areias preparadas por pluviação submersa. Verifica-se através dos resultados de ensaios drenados que as deformações cisalhante e volumétrica são maiores na condição axissimétrica do que na de deformação plana. Tal observação equivale, em solicitações não drenadas, a um acréscimo de poropressão mais acentuado na condição axissimétrica. O comportamento anisotrópico de areias também é revelado com base em ensaios com diferentes direções ( alfa ) da tensão principal maior. Nos ensaios onde alfa = 90 graus Celsius (direção do carregamento perpendicular à de deposição do solo), ocorrem variações de deformação volumétrica e cisalhante bem mais acentuadas do que para alfa = 0 . O programa experimental mostrou ainda que areias calcáreas não cimentadas não apresentam comportamento tensão-deformação acentuadamente diferente do comportamento de areias de quartzo, mais usuais no Brasil.
The subject of this dissertation is a detailed experimental study of the stress-strain-strength behavior of saturated sand under three-dimensional loading condition.The investigation was carried out in a cubic triaxial and a conventional apparatuses. The cubic triaxial apparatus has the advantage of independently controlling the magnitude of the three principal stresses (sigma1, sigma2, sigma3 ) under drained and undrained conditions. Reconstituted specimens of calcareous sand were used in all tests reported in this thesis.The specimens were prepared by pluviation of the sand in destilled water. Special tests were performed following different 3D stress paths. The experimental program was designed for checking the influence of each stress parameter individually. The effects of the inicial anisotropy of sands, caused by the water pluviation method, were also investigated.The results of the drained tests show that the shearing and volumetric strains are larger under axysimmetric than under plane strain condition. In undrained tests this observation would be equivalent to obtaining larger porepressure under axysimmetric conditions. The anisotropic behavior of sands is also noted in tests with different directions (alfa) of the major principal stress. In tests where alfa = 90 Celsius degrees ( direction of load perpendicular to pluviation) the variations in volumetric and shearing strains are much more accentuated than for alfa = 0.The experimental program also shows that the stress-strain behavior of uncemented calcareous sands is not significantly different from the behavior of quartz sands, which are more common in Brazil.
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Merheb, Antonio Hamilton Michel. "Análise mecânica do lastro ferroviário por meio de ensaios triaxiais cíclicos." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/3/3138/tde-20052015-160602/.
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Este trabalho faz parte de uma pesquisa voltada ao estudo do comportamento mecânico do sistema ferroviário e tem foco principal no estudo experimental em laboratório que visa avaliar as características do lastro ferroviário em condições de carga variadas e determinar a influência dos principais parâmetros que afetam o comportamento da estrutura. O material utilizado em camada de lastro ferroviário é normalmente constituído de frações granulométricas graúdas o que dificulta a execução de testes de grande escala em laboratório, devido à robustez necessária do equipamento para representar a correta correspondência entre a amostra e o material de lastro. O principal objetivo deste trabalho foi avaliar a eficiência de um novo aparelho triaxial em larga escala (400mmx800mm), que permite ensaiar agregados graúdos como no campo sem a necessidade de escalonamento da curva granulométrica; analisar a aplicabilidade da técnica de graduação paralela em ensaios triaxiais utilizando equipamento cilíndrico de pequena escala (150mm x 300mm), no qual é mais fácil de manipular pequenas frações, assim como avaliar a influência de duas graduações diferentes sobre deterioração e deformação. Verificou-se que os materiais granulares revelam uma forte tendência de se compactar sob níveis elevados de estresse, causando um aumento significativo de rigidez. A graduação AREMA Nº 24 mostrou-se mais resistente à deformação e a deterioração quando comparada à AREMA Nº 3. O nível de tensões escolhido mostrou-se satisfatório para simular a via permanente sob carregamento, devido à deterioração dos agregados ao final do teste. Além disso, a degradação da amostra contaminada foi mais acentuada que aquela sem finos, demonstrando que o aumento no nível de colmatação implica em perda da durabilidade do lastro, acarretando em necessidade de mais ciclos de correção geométrica e diminuição de sua vida útil. Observou-se que combinação de finos e água no lastro afeta fortemente a resposta mecânica da via permanente, diminuindo sua rigidez e ocasionando instabilidade do sistema, devendo esta situação ser evitada. Os resultados também apontam que o aumento de carga por eixo contribui para uma degradação acelerada dos componentes da via, ocasionando a diminuição do período entre ciclos de manutenção. Os resultados contribuem para uma melhor compreensão do comportamento mecânico da camada de lastro, e desta forma auxiliam no projeto de vias férreas mais eficientes.This work is part of a research focused on studying the mechanical behavior of the railroad system and has a primary focus on experimental laboratory work aimed to evaluate the characteristics of railway ballast under conditions of varying load and determines the influence of the main parameters that affect the behavior of the structure. Materials used in ballast layers are usually comprised of a highly coarse-graded gradation, hence the implementation of large-scale laboratory tests is difficult to conduct due to the corresponding large-scale triaxial specimens for railroad ballast material. The main purpose of this paper was to evaluate the efficiency of a new large-scale triaxial apparatus (400mm x 800mm), that allows testing large-size particles as found in the field without the need of scaling aggregates; the applicability of the parallel gradation technique in triaxial tests using small-scale cylindrical equipment (150mm x 300mm), in which it is easier to manipulate small fractions, as well as to assess the influence of two different gradations on ballast breakage and deformation. It was found that granular materials reveal a strong tendency to settle under higher stress levels, causing a significant increase of their strength and stiffness. The AREMA No. 24 gradation was found to be the most resistant to ballast settlement compared to AREMA No. 3. The stress level chosen was satisfactory to simulate the permanent way under load, due to deterioration of the aggregates at the end of the test. Moreover, the degradation of the contaminated sample was more pronounced than the one without fouling, demonstrating that increased level of fouling implies loss ballast durability, resulting in the need for more rounds of geometric correction and reduction of the life cycle. It was observed the combination of fines and water in the ballast strongly affects the mechanical response of the track, reducing its stiffness and causing system instability, and this situation must be avoided. The results also indicate that increasing axle load contributes to accelerated deterioration of track components, causing a decrease in the period between maintenance cycles. The results contribute to a better understanding of the mechanical behaviour of ballast layer, and thereby assist in the design of more efficient railways.
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Walsh, Thomas George. "The triaxial vane apparatus with stress control." Thesis, University of Ottawa (Canada), 2001. http://hdl.handle.net/10393/6305.
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The scope of this research has been two fold. The first stage was to develop a Tri Vane Apparatus. The Tri Vane Apparatus uses a miniature vane incorporated into a triaxial cell in order to study the use of the vane in different soils as well as allowing the effects of different vane parameters, such as rotation rate and vane geometry, to be studied in controlled conditions. Initial research was conducted into the history of this device with special emphasis on any previous designs. The design used in the current research has incorporated many design aspects used in these previous devices but has also made several improvements. This leads into the second stage of this research. Since the development of the vane test in 1948 by Cadling and Odenstad (1948), the test has almost exclusively been used for the study of the undrained shear strength of clays. This research has investigated the use of the vane test in sands. Through the use of the Tri Vane Apparatus constructed in the first stage of this research, extensive testing has been conducted on sand, in both isotropic and anisotropic stress conditions. (Abstract shortened by UMI.)
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Saussus, Denis. "Membrane contact patterns in triaxial sand specimens." Thesis, Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/19518.
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Karami, Azzam Omar 1962. "Consolidation of clays using the triaxial apparatus." Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/276842.
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The calculation of a consolidation settlement is an important problem encountered in the foundation of buildings. Due to need for simplicity engineers are mainly using the one dimensional theory of Terzaghi for calculations of consolidation settlements with time. Consolidation tests are still performed in most laboratories with the traditional oedometer cell. Although the results of the oedometer can provide relatively reliable results, they are not equally effective for the calculation of the rate of consolidation. This primarily because of the inability of the oedometer cell to obtain full saturation of the sample. To ensure full saturation, back pressure must be applied which is not possible for conventional oedometer cell. The alternative use of the triaxial cell to examine the consolidation behavior of soils is discussed here.
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Minaeian, Vida. "True triaxial testing of sandstones and shales." Thesis, Curtin University, 2014. http://hdl.handle.net/20.500.11937/1283.
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In this study deformational and failure properties of sandstones and shales have been evaluated through laboratory experiments under true triaxial stress conditions. The impacts of intermediate stress and water saturation were investigated. The results indicated that rock strength, elastic moduli, dilatancy behaviour, failure mode and fractures pattern are affected by both the minimum and intermediate principal stresses. Variable water saturation also influences mechanical response of shales. Finally, multistage true triaxial testing was used and examined.
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Soepandji, Budi Susilo. "Contribution à l'étude des propriétés mécaniques des marnes et argiles soumises à de fortes pressions." Châtenay-Malabry, Ecole centrale de Paris, 1986. http://www.theses.fr/1986ECAP0017.
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Ulloa, Calderon Alvaro. "Characteristics of dynamic triaxial testing of asphalt mixtures." abstract and full text PDF (UNR users only), 2009. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1472985.
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John, James Daniel, and james d. john@gmail com. "An Adaptively Controlled MEMS Triaxial Angular Rate Sensor." RMIT University. Electrical and Computer Engineering, 2006. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20070112.162019.
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Prohibitive cost and large size of conventional angular rate sensors have limited their use to large scale aeronautical applications. However, the emergence of MEMS technology in the last two decades has enabled angular rate sensors to be fabricated that are orders of magnitude smaller in size and in cost. The reduction in size and cost has subsequently encouraged new applications to emerge, but the accuracy and resolution of MEMS angular rate sensors will have to be greatly improved before they can be successfully utilised for such high end applications as inertial navigation. MEMS angular rate sensors consist of a vibratory structure with two main resonant modes and high Q factors. By means of an external excitation, the device is driven into a constant amplitude sinusoidal vibration in the first mode, normally at resonance. When the device is subject to an angular rate input, Coriolis acceleration causes a transfer of energy between the two modes and results in a sinusoidal motion in the second mode, whose amplitude is a measure of the input angular rate. Ideally the only coupling between the two modes is the Coriolis acceleration, however fabrication imperfections always result in some cross stiffness and cross damping effects between the two modes. Much of the previous research work has focussed on improving the physical structure through advanced fabrication techniques and structural design; however attention has been directed in recent years to the use of control strategies to compensate for these structural imperfections. The performance of the MEMS angular rate sensors is also hindered by the effects of time varying parameter values as well as noise sources such as thermal-mechanical noise and sensing circuitry noise. In this thesis, MEMS angular rate sensing literature is first reviewed to show the evolu- tion of MEMS angular rate sensing from the basic principles of open-loop operation to the use of complex control strategies designed to compensate for any fabrication imperfections and time-varying effects. Building on existing knowledge, a novel adaptively controlled MEMS triaxial angular rate sensor that uses a single vibrating mass is then presented. Ability to sense all three components of the angular rate vector with a single vibrating mass has advantages such as less energy usage, smaller wafer footprint, avoidance of any mechanical interference between multiple resonating masses and removal of the need for precise alignment of three separate devices. The adaptive controller makes real-time estimates of the triaxial angular rates as well as the device cross stiffness and cross damping terms. These estimates are then used to com- pensate for their effects on the vibrating mass, resulting in the mass being controlled to follow a predefined reference model trajectory. The estimates are updated using the error between the reference model trajectory and the mass's real trajectory. The reference model trajectory is designed to provide excitation to the system that is sufficiently rich to enable all parameter estimates to converge to their true values. Avenues for controller simplification and optimisation are investigated through system simulations. The triaxial controller is analysed for stability, averaged convergence rate and resolution. The convergence rate analysis is further utilised to determine the ideal adaptation gains for the system that minimises the unwanted oscillatory behaviour of the parameter estimates. A physical structure for the triaxial device along with the sensing and actuation means is synthesised. The device is realisable using MEMS fabrication techniques due to its planar nature and the use of conventional MEMS sensing and actuation elements. Independent actuation and sensing is achieved using a novel checkerboard electrode arrangement. The physical structure is refined using a design automation process which utilises finite element analysis (FEA) and design optimisation tools that adjust the design variables until suitable design requirements are met. Finally, processing steps are outlined for the fabrication of the device using a modified, commercially available polysilicon MEMS process.
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Ossa, Tajura Getachew. "Behaviour of Keswick clay under triaxial compression conditions /." Title page, abstract and contents only, 1998. http://web4.library.adelaide.edu.au/theses/09ENS/09enso84.pdf.
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Li, Kim Mui S. T. "Pore pressure in concrete : theory and triaxial tests." Thesis, University of Cambridge, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233289.
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MUNIZ, EUDES SIQUEIRA. "NEW METHODOLOGY FOR TESTING SHALES UNDER TRIAXIAL STRESSES." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1998. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=1535@1.
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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOROs folhelhos correspondem a mais de 75% das formações perfuradas para exploração de hidrocarbonetos e cerca de 90% dos problemas de instabilidade em poços de petróleo são atribuídos a ele. Segundo Steiger & Leung (1991), são gastos de 600 milhões a 1 bilhão de dólares anuais com custos adicionais de perfuração, gerados por problemas de instabilidade em poços. Este trabalho propõe uma nova metodologia de ensaio triaxial axissimétrico CIU em folhelhos, capaz de obter os parâmetros necessários para análises de instabilidade em períodos de tempo relativamente curtos. Esta metodologia está baseada em procedimentos normalmente utilizados em ensaios de solos e emprega equipamentos específicos de testes em rochas. Foram realizados 12 ensaios triaxiais divididos em duas campanhas em um folhelho proveniente da Bacia de Campos. Os resultados dos ensaios comprovam a eficácia da nova metodologia. O comportamento de resistência destes folhelhos é descrito utilizando o critério linear de resistência de Mohr-Coulomb com coesão de 3,17 MPa e um ângulo de atrito interno de 25,3º.
Shales constitute more than 75% of the drilled rocks in the search for hydrocarbons and an estimated high 90% of wellbore instability problems are credited to their presence. According to Steiger & Leung (1991), more than 600 Million US dollars are spent annually by the oil industry just to corrent the problems due to instabilities. This work presents a new methodology for running triaxial compression tests in shales under undrained conditions. This methodology allows shorter duration of the tests and it is based upon adaptation of concepts traditionally employed in the soil mechanics field. 12 tests have been carried out in shales obtained from offshore Brazil during this work. The tests were divided into 2 groups based upon the nature of the fluid used in the pore pressure lines. The tests results show that this methodology is very efficient. The shear strength behavior of the shale is described and by using the Mohr-Coulomb criterium, the shear strength parameters are a cohesion of 3,17 MPa and phase equal to 25,3°.
Los folhelhos corresponden a más del 75% de las formaciones perforadas para exploración de hidrocarbonetos y a ellos le son atribuidos cerca de 90% de los problemas de inestabilidad en pozos de petróleo. Según Steiger & Leung (1991), se gastan de 600 millones a 1 billión de dólares anuales con costos adicionales de perforación, generados por problemas de inestabilidad en pozos. Este trabajo propone una nueva metodología de ensayo triaxial axisimétrico CIU en folhelhos, capaz de obter los parámetros necesarios para el análisis de inestabilidad en períodos de tiempo relativamente cortos. Esta metodología está basada en procedimientos normalmente utilizados en ensayos de suelos y emplea equipos específicos de pruebas en rocas. Fueron realizados 12 ensayos triaxiales divididos en dos campañas en un folhelho proveniente de la Bacia de Campos. Los resultados de los ensayos comproban la eficacia de la nueva metodología. Para describir el comportamiento de la resistencia de estos folhelhos se utiliza el criterio lineal de resistencia de Mohr-Coulomb con cohesión de 3,17 MPa y un ángulo de fricción interno de 25,3º.
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Kueh, Ahmad Beng Hong. "Thermo-mechanical properties of triaxial weave fabric composites." Thesis, University of Cambridge, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.612022.
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Sachania, Jalpesh. "Orbital decay in triaxial shaped dark matter haloes." Thesis, University of Leicester, 2010. http://hdl.handle.net/2381/30598.
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In cosmological simulations of structure formation of the universe, the dark matter halos in which galaxies are embedded in, are triaxial in shape. Simulations which focus in on galaxies in isolation do not use triaxial dark matter halos but use spherical shaped halos instead, as triaxial equilibrium models are hard to create.;Using a new method of creating initial conditions, which is able to create triaxial equilibrium models, the effect of using a triaxial halo in simulations of satellite accretion will be studied. In previous studies with a spherical shaped dark matter halo, the initial position of the satellite is unimportant due to the symmetry of the system, however in a triaxial halo this is not the case and the initial position becomes important. A study of the parameter space of the initial position and velocity of a satellite is undertaken and the orbital decay is compared in each case.;The different mergers will also have different effects upon the halo itself as the orbital energy of the satellite is transferred to the halo. The effects of a minor merger onto the halo is investigated and compared to the scenario more commonly used when the halo is spherical.;This study is then extended to find out whether the orbital decay in a triaxial potential, which can differ significantly from that in a spherical halo, can be used to explain the observations of polar ring galaxies and gas discs in elliptical galaxies.
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Ambrose, Jasmin. "Failure of anisotropic shales under triaxial stress conditions." Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/19270.
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Shales are highly anisotropic in their mechanical behaviour. The strength of anisotropic shales depends not only on the magnitude of the principal stresses, but also on the bedding plane orientations relative to the principal stresses. In this study, the failure of shales are investigated using triaxial compression and extension tests, while the role of intermediate stress (sigma2) on the strength of anisotropic shale is evaluated using data from new triaxial extension tests, as well as data from the literature. Triaxial compression and extension experiments were made on two organic-rich shales, at different confining stresses and bedding angles (Beta). Examination of post-failure computed tomography (CT) and thin section images for high strength anisotropy shale show that, for large and small values of Beta, the fracture plane follows the angle that is predicted by the Coulomb’s failure criterion for an isotropic material. In the range of angles of roughly 35deg.
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Sun, Mingkun Sun. "MULTISCALE HYBRID ELEMENT MODELING OF TRIAXIAL BRAIDED COMPOSITE." University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1533550804106857.
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Younessi, Sinaki Ahmad Reza. "Sand production simulation under true-triaxial stress conditions." Thesis, Curtin University, 2012. http://hdl.handle.net/20.500.11937/1133.
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Sand production in weakly consolidated sandstone reservoirs could result in damaging the production and surface facilities. Sanding includes two stages: the failure of sandstone around the borehole and sand grains being transported into the borehole. The first stage is related to stresses around the borehole whereas the second one is controlled by drawdown pressure. In order to avoid sanding, the stresses around the borehole and the drawdown pressure which initiate sanding are studied.This research simulated sand production through laboratory experiments and numerical simulations. The effect of three independent far-field stresses was investigated which is contrary to most of the current studies being performed under a uniaxial or triaxial stress state. Accordingly, a unique experimental setup and procedure was introduced to conduct sand production experiments under true-triaxial stress conditions. The effect of drawdown pressure and state of far-field stresses on the sanding mechanism and development of the failure zone around a borehole were investigated. The experiments were conducted on 100×100×100 mm3 cubic samples of synthetic sandstones. The samples were manufactured using an established procedure developed to produce samples with properties similar to weakly consolidated sandstone. The properties of the synthetic sandstone samples were determined by conducting a series of standard rock mechanics tests on cylindrical plugs. Using a true-triaxial stress cell (TTSC), cubic samples were subjected to three independent boundary stresses and uniform lateral fluid flow from the outer boundaries. The fluid flows through the sample radially and discharges from a hole drilled at the centre of the sample: this allows the study of sanding initiation by changing the state of stress, sample material and fluid properties.In this research, firstly, the concept of sand production from a geomechanics point of view and a summary of previous sanding experiments are explained. Thereafter, the procedure to prepare a sample suitable for sand production experiments is provided. Subsequently, the experimental equipment, setup and procedure are explained in detail. This is followed by presenting the results of two sets of experiments performed at different states of stress. The effect of changing the lateral stresses on the development of the failure zone around borehole was investigated in these experiments. During these experiments it was observed that a minimum drawdown pressure is needed to initiate sand production, regardless of the state of the boundary stresses. In addition, it was observed that the geometry (i.e. width and depth) of the failure zone developed around the borehole is a function of the state of stresses.The experiments were also simulated numerically using ABAQUS in order to gain a better understanding of sand production mechanisms. The numerical modelling procedure and results are presented in a separate section in this thesis. Good agreement was obtained between the results of both experimental and numerical methods which confirm the importance of the state of stresses on the evolution of sanding. Based on the experimental and numerical observations, it was shown that the effect of the magnitude of the maximum lateral stress on the depth of failure is more significant than the minimum lateral stress.
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Taghzouti, Abdellatif. "Comportement cyclique tridimensionnel des sols : Expérience et modélisation." Châtenay-Malabry, Ecole centrale de Paris, 1995. http://www.theses.fr/1995ECAP0442.
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L'objectif de ce travail est d'améliorer nos connaissances sur le comportement tridimensionnel des sols, utilisant un appareil triaxial vrai de l'École centrale de Paris, en particulier pour des sollicitations cycliques avec une rotation instantanée des directions principales des contraintes en conditions non drainées. L'analyse des résultats des essais triaxiaux tridimensionnels sur la kaolinite P300 et le sable d'hostun saturés, caractérise le rôle de la contrainte principale intermédiaire dans le cas des essais monotones suivant des chemins radiaux. Des relations entre les déformations principales d'une part et les contraintes effectives d'autre part ont été déduits, à partir des essais cycliques réalisés avec une rotation instantanée, par a coups de quatre vingts dix degrés, des directions principales des contraintes. Une procédure de pilotage de la loi de comportement de Hujeux a été introduite, elle nous a permis de faire le calage de la loi sur ces chemins triaxiaux complexes. Les résultats obtenus ont contribue à l'évaluation des capacités du modèle
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Allmond, James Mitchell. "Studies of Triaxial Rotors and Band Mixing in Nuclei." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14604.
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Rigid rotor models were investigated with constraints from data for even-even nuclei. Specifically, from precision gamma-ray intensity measurements for 166-Er (from 166m-Ho and 166-Tm beta decays); from B(E2) systematics; and for 186,188,190,192-Os matrix element data.
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Machado, Rubens Eduardo Garcia. "Dynamics of Barred Galaxies in Triaxial Dark Matter Haloes." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/14/14131/tde-02122011-111155/.
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Cosmological N-body simulations indicate that the dark matter haloes of galaxies should be generally triaxial. Yet, the presence of a baryonic disc is believed to modify the shape of the haloes. The goal of this thesis is to study how bar formation is affected by halo triaxiality and how, in turn, the presence of the bar influences the shape of the halo. We performed a series of collisionless and hydrodynamical numerical simulations, using elliptical discs as initial conditions. Triaxial halos tend to become more spherical and we show that part of the circularisation of the halo is due to disc growth, but part must be attributed to the formation of a bar. We find that the presence of gas in the disc is a more efficient factor than halo triaxiality in inhibiting the formation of a strong bar.As simulações cosmológicas de N-corpos indicam que os halos de matéria escura das galáxias devem ser em geral triaxiais. Contudo, acredita-se que a presença de um disco bariônico seja capaz de alterar a forma do halo. O objetivo desta tese é o de estudar como a formação de barras é afetada pela triaxialidade do halo e como, por sua vez, a presença da barra influencia a forma do halo. Nós realizamos uma série de simulações numéricas acolisionais e hidrodinâmicas, utilizando discos elípticos como condições iniciais. Os halos triaxiais tendem a se tornar mais esféricos e nós mostramos que parte da circularização do halo é devida ao crescimento do disco, mas parte precisa ser atribuída à formação da barra. Notamos que a presença de gás no disco é um fator mais eficiente do que a triaxialidade do halo em inibir a formação de uma barra forte.
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Lira, Emidio Neto de Souza. "Sistema automático de aquisição de dados para ensaio triaxial." Universidade Federal do Rio de Janeiro, 1988. http://hdl.handle.net/11422/3805.
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Esta dissertação descreve inicialmente os componentes de sistemas de aquisição de dados baseados em microcomputadores, sua utilização em ensaios geotécnicos e as dificuldades que podem surgir com a implantação dos mesmos. Apresenta-se a seguir o sistema automático de aquisição de dados implantado no Laboratório de Geotecnia da COPPE. O sistema implementado foi utilizado no acompanhamento de ensaios triaxiais não-drenados dos tipos UU e CIU, sendo os resultados dos mesmos apresentados em formato de relatórios. O material ensaiado foi uma argila mole da região do Caju, na Baía da Guanabara, retirada sob um aterro sanitário. Os resultados dos ensaios são analisados à luz da teoria dos estados críticos como forma de dar subsídios à uma futura retro-análise da ruptura ocorrida no local de extração do material.
Microcomputer based data acquisition system are initially described. The use of these systems for geotechnical tests and the dificulties that may arise when implementing these systems are emphasised. The data acquisition system at the COPPE Geotechnical Laboratory is subsequently described. This system was used to log undrained triaxial tests, the results of these being presented in a report type format. The material tested was a soft clay of the Caju District close to Guanabara Bay and sampled under a failed sanitary fill. Test results are analised in the ligth of critical state soil mechanics theory. This is hoped to contribute to the back calculation of the sanitary fill failure.
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Machado, Rubens. "Dynamics of barred galaxies in triaxial dark matter haloes." Aix-Marseille 1, 2010. http://theses.univ-amu.fr.lama.univ-amu.fr/2010AIX11051.pdf.
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Des simulations cosmologiques à N-corps indiquent que les halos de matière noire des galaxies devraient être généralement triaxiaux. Pourtant, on croit que la présence d’un disque baryonique modifie la forme des halos. L’objectif de cette thèse est d’étudier comment la formation des barres est affectée par la triaxialité des halos et comment, à son tour, la présence de la barre influence la forme du halo. Nous réalisons un ensemble de simulations numériques non-collisionnelles et hydrodynamiques, utilisant des disques elliptiques comme conditions initiales. Les halos triaxiaux ont tendance à devenir plus sphérique et nous montrons qu’une partie de la circularisation du halo est due à la croissance du disque, mais une partie doit être attribuée à la formation d’une barre. Nous trouvons que la présence du gaz dans le disque est un facteur plus efficace que la triaxialité du halo pour inhiber la formation d’une barre forteCosmological N-body simulations indicate that the dark matter haloes of galaxies should be generally triaxial. Yet, the presence of a baryonic disc is believed to modify the shape of the haloes. The goal of this thesis is to study how bar formation is affected by halo triaxiality and how, in turn, the presence of the bar influences the shape of the halo. We performed a series of collisionless and hydrodynamical numerical simulations, using elliptical discs as initial conditions. Triaxial halos tend to become more spherical and we show that part of the circularisation of the halo is due to disc growth, but part must be attributed to the formation of a bar. We find that the presence of gas in the disc is a more efficient factor than halo triaxiality in inhibiting the formation of a strong bar
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Oancea, Alexandru (Alexandru Adrian) Carleton University Dissertation Engineering Civil and Environmental. "Triaxial compression of soils reinforced with discrete synthetic fibres." Ottawa, 1996.
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Song, Yongxiang. "Réalisation du système triaxial assisté par ordinateur et étude du cisaillement direct 3D pour joints rocheux." Grenoble 1, 1992. http://www.theses.fr/1992GRE10209.
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On presente dans cette these un systeme triaxial assiste par ordinateur et un appareillage de cisaillement direct pour joints rocheux. Ce systeme triaxial de revolution est constitue par une presse electromecanique commerciale et deux controleurs pression-volume, ainsi qu'un micro-ordinateur avec une carte d'acquisition (a/n, n/a et e/s). Ce systeme pilote par l'ordinateur peut realiser tous les essais triaxiaux asservis en deformation ou en contrainte, ainsi que des essais cycliques. Un nouvel essai en escalier, draine ou non draine, est presente. Ce type de chemin trouve son interet dans des simulations de comportement pour connaitre des deformations resultant d'increments de contraintes apportes par des ouvrages. Ce systeme developpe recemment est analyse par les resultats des essais et par une comparaison entre deux modes d'asservissement. Quelques criteres sont presentes pour garantir la qualite d'asservissement ainsi que la reussite des essais. La precision du systeme et les facteurs resultant des erreurs sont aussi discutes. Le cisaillement direct pour joints rocheux est en cours de developpement dans la version 2d et sera transforme ulterieurement dans la version 3d. Il est possible de realiser les essais de cisaillement direct en trois modes de sollicitation (axisymetrique, homogeneite cinematique et homogeneite statique). Le principe du projet et le mode d'asservissement sont presentes avec leur calcul
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Tadesse, Samuel. "Behaviour of saturated sand under different triaxial loading and liquefaction." Doctoral thesis, Norwegian University of Science and Technology, Department of Civil and Transport Engineering, 2000. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-2328.
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Mukasa, Jacob. "Aspects of triaxial testing and development of a learning system." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for bygg, anlegg og transport, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-14526.
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The triaxial test is designed to measure the effective shear strength of the selected soil sample or solid. Normally, the sample shear strength is derived from the obtained parameters of the soil samples tested. Triaxial tests is very reliable because it can be used to measure strength of the material in both saturation and dry conditions, as well as both drained and undrained. Currently the new equipment has been developed by the geotechnical division of the Norwegian University of Science and Technology for triaxial testing of soil. The simplified and reliable procedures for the use of this specific new triaxial equipment have to be developed for academic purposes, mainly for students’ use. The developed procedures have to include the report which covers the triaxial test background; types of triaxial tests mostly those which can be done using this triaxial equipment; the equipment and its devices and how they work together and the trial tests results which will be done using this equipment. With this report, the online students help video was developed during trial triaxial tests. The online students help video shows sample preparation and placing it on the equipment for both insitu and build up. Clay sample was used for insitu undisturbed samples while sand was used for build up samples. It also shows how to do the pre test checkups including flushing the filter stones and regulating the confining pressure. The video shows how to start the consolidation and how to determine when the consolidation is over and how to start the shearing phase. Lastly it shows how to remove the sample when the test is done. Several triaxial tests were done on this equipment (The results of the two trial tests are attached to this report as Appendix A) to evaluate how it is working as well as its performance, and the outputs were interpreted as shown in the following chapters. These tests were done in different types of soil with varying conditions in consolidation and drainage. The total of two trial tests were done using this equipment, using the developed procedure, this tests including; 1: Consolidated Undrained Triaxial test (Compression) on clay 2: Consolidated Drained Triaxial test (Extension) on sand
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Mathie, Merryn Joy Electrical Engineering & Telecommunications Faculty of Engineering UNSW. "Monitoring and interpreting human movement patterns using a triaxial accelerometer." Awarded by:University of New South Wales. School of Electrical Engineering and Telecommunications, 2003. http://handle.unsw.edu.au/1959.4/27386.
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This thesis addresses the hypothesis that a single, waist-mounted triaxial accelerometer (TA) can be used to monitor human movement patterns in unsupervised, freeliving subjects over extended periods, and that it can be used to quantitatively measure parameters that can provide clinical insight into the health status of the subject. A rigorous theoretical and experimental understanding of the signals obtained from a TA is developed. The effect of the placement of the TA device on the waist is explored and a model relating device position to TA signal is developed for a range of postures and activities. A classification framework for movement identification using the signals from a waist-mounted TA is presented. This framework is based on a hierarchical binary processing tree and is designed for real time use. An implementation of this framework for monitoring housebound patients is presented. Algorithms for detecting falls, distinguishing between activity and rest, classifiying transitions between different postural orientations, and for identifying periods of standing, sitting, lying and walking are developed. In evaluation studies performed in controlled laboratory conditions, every algorithm performed with better than 90% accuracy. Once movements are identified, movement-specific parameters sensitive to changes in functional status are extracted from the signal. A two stage methodology for employing the accelerometry system in monitoring free-living subjects is introduced. The first stage involved monitoring specific movements through a directed routine. The second stage involved monitoring of free movement. Signals obtained from the directed routine are used to extract clinically relevant, movement-specific parameters. Signals obtained from the period of free movement are monitored for falls and other abnormal events. General parameters of movement, including energy expenditure, are also measured. The system was evaluated in a series of field studies in laboratory and home environments, in supervised and unsupervised settings, using cohorts of healthy subjects. A pilot trial was conducted in which six healthy elderly subjects wore the TA device for a period of up to three months. The technical performance and useability of the system were evaluated. Clinically significant parameters were measured and the effects of age and health status on the measured parameters were evaluated.
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Lau, W. H. W. "The behaviour of clay in simple shear and triaxial tests." Thesis, City University London, 1988. http://openaccess.city.ac.uk/8347/.
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The main objective of this work is to study the applications of critical state soil mechanics to simple shear testing. The problems with the simple shear apparatus and the approach for interpreting simple shear test results are described. Laboratory tests were conducted using the NGI simple shear apparatus, standard shear box arid computer controlled stress path testing equipment for samples with 38 mm and 100 mm diameter. The test programme comprised simple shear and shear box tests on remouled, reconstituted and undisturbed samples of Cowden till and London clay, undrained triaxial tests on reconstituted arid undisturbed London clay and stress probing tests on undisturbed London clay. Simple shear samples were tested under either constant effective vertical stress or constant volume condition. Basic results for one-dimensional compression arid for shearing obtained from 72 simple shear tests, 27 shear box tests and 16 stress path tests are presented. Analyses of the simple shear test results indicate that the critical state friction angle for horizontal planes is dependent on whether the sample was sheared under constant or constant volume condition and on the pre-shearing value of K0 which is a function of overconsolidation ratio. A theory for the critical states of simple shear tests which takes into account the influence of K0 is proposed. The normalised test data show that the overall patterns of the simple shear and triaxial tests are as predicted by the critical state model. Tangent stiffnesses instead of secant stiffnesses were calculated. For simple shear tests, the shear stiffnesses obtained from constant shearing are the same as those obtained from constant volume shearing. For London clay, the normalised shear moduli for undrained triaxial tests have the same order of magnitude as those for constant volume simple shear tests. Results of probing tests show that undisturbed London clay is linear anisotropic elastic. The elastic parameters for the constitutive equations can be measured from special stress paths.
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FERREIRA, SUELI APARECIDA. "DEVELOPMENT OF A TRIAXIAL CELL FOR LABORATORY TESTS OF ROCKS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1997. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=1933@1.
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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOROs maciços rochosos encontram-se submetidos a estados biaxiais e triaxiais de tensão. O conhecimento da deformabilidade e da resistência das rochas sob tais condições é fundamental para o cálculo da capacidade de suporte de fundações em rochas, projeto de barragens, mineração, prospecção e extração de petróleo, construção de túneis, etc. Para tanto, a realização de ensaios, quer sejam de campo ou de laboratório, é de grande valia. Devido à dificuldade de realização de ensaios biaxiais, e sendo a solicitação triaxial a mais comum, é bastante pertinente o estudo do comportamento das rochas quando submetidas a tal carregamento. O objetivo do presente trabalho é o desenvolvimento de uma célula triaxial para ensaios de laboratório em rochas, capaz de suportar uma pressão confinante de até 70 MPa. O equipamento permite instrumentação interna dos corpos de prova. Foi prevista a obtenção de medidas de poropressão, tanto de topo quanto de base, e a possibilidade de percolação de fluido pelo espécime ensaiado. A fim de se caracterizar o equipamento, foram executados ensaios em espécimes de aço e rocha. A rocha estudada foi um gnaisse leptinito encontrado no município do Rio de Janeiro (Morro Dona Marta).
Rock masses are submitted to biaxial and triaxial states of stress. Deformability and strength properties of rocks under such conditions are essential data for calculating bearing capacity of foundations, design of dams, mining excavations, oil exploration, tunnelling etc. For these purposes, laboratory and in situ tests are of great importance. Studying rock behaviour when submitted to triaxial loading is of great concern, due to the difficulty in carrying out biaxial tests and because triaxial state of stress is more common. This thesis presents the design and construction of a triaxial cell for laboratory tests in rocks, which is able to support a confining pressure as high as 70 MPa. The equipment allows internal specimen instrumentation. Top and bottom pore-pressure measurements have been predicted, and fluid percolation through the specimen is possible. Tests on steel and rock specimens were carried out to comission the equipment. The rock tested is a leptinite gneiss found in the city of Rio de Janeiro (Morro Dona Marta).
Los macizos rocosos se encuentran sometidos a estados de tensión biaxiales y triaxiales. El conocimiento de la deformabilidad y de la resistencia de las rocas bajo tales condiciones es fundamental para el cálculo de la capacidad de soporte de fundaciones en rocas, proyecto de presas, mineración, prospección y extracción de petróleo, construcción de túneles, etc. De aqui la importancia de la realización de ensayos, ya sean de campo o de laboratorio. Considerando la dificuldad para la ejecución de ensayos biaxiales, y como la solicitación triaxial es la más común, resulta pertinente el estudio del comportamiento de las rocas cuando son sometidas a tal carga. EL objetivo del presente trabajo es el desarrollo de una célula triaxial para ensayos de laboratorio en rocas, capaz de soportar una presión de confinación de hasta 70 MPa. El equipo permite la instrumentación interna de los cuerpos de prueba. Fue previsto obtener medidas de poropresión, tanto de pico cuanto de base, y la posibilidad de percolación de fluido por el espécimen ensayado. Con el objetivo de caracterizar el equipo, se ejecutaron ensayos en espécimes de acero y roca. La roca estudada fue un gnaise leptinito encontrado en el município del Rio de Janeiro (Morro Dona Marta).
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PALACIOS, MIGUEL ANGEL PARODI. "BEHAVIOR OF A POLYPROPYLENE REINFORCED SAND UNDER TRIAXIAL EXTENSION TESTS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2012. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=21788@1.
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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIORO presente trabalho permite avaliar o comportamento de um solo reforçado e não reforçado com fibras de polipropileno (teor de 0.5 por cento em relação ao peso seco do solo) submetido a ensaios triaxiais de extensão, bem como a influência da adição de fibras na resistência e nos mecanismos de ruptura do solo reforçado. Para tanto, desenvolveu-se um programa experimental compreendendo a etapa final de um equipamento triaxial do tipo Bishop e Wesley de grandes dimensões e a execução de ensaios triaxiais drenados de extensão. Os ensaios triaxiais realizados permitiram a determinação dos parâmetros de resistência do solo e da mistura solo–fibra. Os resultados obtidos propiciaram a um melhor entendimento das alterações geradas pela inclusão aleatória de fibras de polipropileno à matriz da areia estudada. O desempenho das fibras no interior da massa de solo indica que estas sofreram deformações plásticas de tração, alongando-se, porém este alongamento é atribuído à fase de adensamento e não à fase de cisalhamento dos ensaios triaxiais de extensão realizados, já que foi possível observar que a adição das fibras não incrementa a resistência à tração do solo, quando este estiver submetido a esforços de extensão.
The present study allows evaluating the behavior of a reinforced and unreinforced soil with fibers of polypropylene (0.5 per cent content of dry weight of soil) subjected to triaxial extension tests, as the influence of adding fibers in the resistance and the rupture mechanisms of reinforced soil. Therefore, it was developed an experimental program comprising the development of a Bishop and Wesley’s triaxial-type equipment which has a larger size than conventional triaxial equipment and an execution of drained triaxial extension tests. The present study submits triaxial tests results aiming the determination of strength parameters of soil and soil – fiber mixture. The obtained results led a better understanding of the alterations generated by the random inclusion of polypropylene fibers to the pattern sand studied. The accomplishment of fiber performance within soil mass indicates that they undergo tensile plastic deformation, elongating, but this elongating is attributed to shear stage in the triaxial extension tests realized, as was conferred that the addition of fiber does not increase the tensile strength of soil.
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Ayan, Kathryn Donna June. "Undrained triaxial strength-deformation behavior of Harrison Bay Arctic silts." Thesis, Massachusetts Institute of Technology, 1985. http://hdl.handle.net/1721.1/67097.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1985.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING
Bibliography: leaves 238-241.
by Kathryn Donna June Ayan.
M.S.
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Corless, Virginia Leigh. "Light around darkness : gravitational lensing by triaxial galaxies & clusters." Thesis, University of Cambridge, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.611161.
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Younes, Ahmad. "Étude à l'appareil triaxial du module de déformation des sols." Lille 1, 1999. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/1999/50376-1999-177.pdf.
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Le présent travail comporte une étude expérimentale du module de déformation des sols dans la gamme des déformations (10-4 – 10-3). L'étude est réalisée à l'appareil triaxial suivant des chemins de chargement variés : drainé, non drainés, à pression moyenne constante et à déformations proportionnelles. Le rapport de thèse comporte trois chapitres : le premier chapitre présente une analyse bibliographique des travaux publies dans le domaine de petites déformations. Ces travaux ont été réalisés avec un certain nombre d'appareillage comme l'appareil triaxial, la machine de torsion et les dispositifs de mesure des fréquences de résonance des échantillons de sol. Dans un premier temps, on définit les domaines de comportement des sols, puis on met en évidence la sensibilité du comportement en petites déformations à un certain nombre de paramètres. Ce chapitre s'achève par une présentation des modèles proposes pour décrire le comportement élastique des sols. Dans le deuxième chapitre, on fait une description de l'appareillage utilise ainsi que du mode opératoire suivi. Les tests de répétabilité ont montré le bon fonctionnement de l'appareillage et sa capacité à faire des mesures pour des déformations supérieures 2x10-4. Ensuite, on présente les premiers résultats du comportement global du sable d'Hostun RF obtenus sur différents chemins de chargement avec cycles de déchargement - rechargement. Ces résultats sont comparés à des essais monotones. On en déduit que les cycles de chargement rendent l'échantillon plus homogène en réduisant la localisation des déformations et le pic de contraintes associé. Le troisième chapitre est consacré à l'analyse des cycles de déchargement - rechargement réalisés sur divers chemins de sollicitations. A partir de ces cycles, on détermine le module de déformation sécant et on étudie sa variation avec un certain nombre de paramètres, notamment le niveau de déformation, la pression moyenne, la densité et l'histoire de chargement. Ce module sécant augmente avec le niveau de contraintes et/ou avec la densité relative. L'anisotropie créée par l'histoire du chargement fait augmenter également le module sécant. Une confrontation des différents chemins de chargement montre un bon accord entre les valeurs des modules sur ces chemins.
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Li, Yuan. "Triaxial strongly deformed band and high spin states in 168Lu." Master's thesis, Mississippi State : Mississippi State University, 2003. http://library.msstate.edu/etd/show.asp?etd=etd-03132003-141252.
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Khatrush, Suleiman Ali. "The yielding of a fine sand in triaxial stress space." Thesis, University of Surrey, 1987. http://epubs.surrey.ac.uk/841582/.
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This thesis contains an experimental investigation of the yielding behaviour of sand loaded in triaxial compression, extension and a combination of both (stress reversal). The testing programme was conducted on 102 x 205 mm medium dense samples of fine Leighton Buzzard sand. A considerable part of the work was directed towards improving the testing technique in order to obtain good quality data. For this purpose, an automated stress path system was constructed and programmed utilizing a microcomputer to take full control of the applied stresses so that any desired stress path could be closely followed in the conventional triaxial cell. Furthermore, new displacement measuring devices were developed and used throughout the testing programme for monitoring both axial and radial deformation locally on the middle third of the triaxial specimen. The results indicate that generally the behaviour of sand is highly anisotropic and that during non-reversal stress paths, the yield condition can be described by a set of curved yield loci in the p' - q stress space. Such yield loci have more curvature in extension than in compression. Stress reversal is found to cause a significant softening of the stress-strain behaviour. However, depending on the level of deviatoric prestress on the opposite side, the sand may become even softer than in the virgin stress-strain condition. The typical errors likely to occur during conventional deformation measurement are discussed, and it is concluded that the use of local measurement should replace both external axial and volumetric monitoring techniques.
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Chazallon, Cyrille. "Modélisation du comportement mécanique de géomatériaux cimentés." Châtenay-Malabry, Ecole centrale de Paris, 1996. http://www.theses.fr/1996ECAP0517.
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Afin de modéliser le comportement mécanique de géomatériaux cimentés sous chargements monotones, un modèle élastoplastique couplé avec un modèle élastique avec endommagement a été développé. Ce modèle va prendre en compte les aspects cohérents et frottant de ces matériaux. Les principes à la base du modèle sont présentés ainsi que l'interprétation physique des paramètres qui ont été utilisés. Afin d'illustrer les capacités du modèle à reproduire le comportement mécanique des géomatériaux cimentés, nous avons simulé des essais triaxiaux sur différents matériaux : une argile profonde cimentée dont l'hétérogénéité des échantillons est liée à la quantité de carbonate de calcium contenue dans l'échantillon, un assemblage de billes de verre frittées et un sable artificiellement cimenté. Pour ce dernier, les différentes contraintes de confinement nous permettent de mettre en évidence la transition fragile - ductile qui a été modélisée en introduisant la contrainte moyenne effective dans la loi d'évolution de l'endommagement. Nous démontrons que les paramètres de chacune des parties du modèle peuvent être adaptés pour reproduire les tendances observées. Pour des liens peu rigides, la partie élastoplastique joue le rôle prédominant, tandis que pour des liens très rigides la partie élastique avec endommagement gouverne le comportement mécanique. Enfin, dans l'optique de mettre en évidence le rôle de la cimentation dans un sable lors de la liquéfaction, nous avons réalisé des simulations de chargements cycliques pour divers degrés de cimentation.
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Malysz, Rodrigo. "Desenvolvimento de um equipamento triaxial de grande porte para avaliação de agregados utilizados como camada de pavimentos." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2009. http://hdl.handle.net/10183/19046.
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Camadas granulares desempenham um importante papel no comportamento global de pavimentos, especialmente daqueles com revestimentos delgados ou sem revestimento. Para conhecer as características de resistência e deformabilidade de materiais componentes dessas camadas são realizados ensaios triaxiais. No caso de ensaios em materiais granulares, o corpo de prova deve ter diâmetro de pelo menos cinco vezes o tamanho máximo de partícula e altura igual a duas vezes o seu diâmetro. Como as especificações do DNIT permitem o emprego de agregados de até 5 cm em camadas de brita graduada ou solo-agregado, os corpos-de-prova devem ter diâmetro de 25 cm e altura de 50 cm. Equipamentos capazes de ensaiar corpos-deprova com estas dimensões são raros no mundo e inexistiam no Brasil até 2008. Com o intuito de superar esta carência e avançar no conhecimento do comportamento mecânico de agregados graúdos, a pesquisa relatada nesta tese teve como objetivos desenvolver um equipamento triaxial de grande porte capaz de aplicar carregamentos estáticos, monotônicos e cíclicos em corpos-de-prova de grandes dimensões (25 cm x 50 cm); bem como realizar e interpretar os primeiros ensaios. A concepção e a montagem do equipamento são descritas considerando as partes principais. Também é detalhada a instrumentação utilizada composta por: duas células de carga, três transdutores de deslocamento e dois transmissores de pressão. Para os primeiros ensaios foi escolhida uma brita graduada de basalto, anteriormente utilizada em pistas experimentais solicitadas por simulador de tráfego. Ensaios em corpos-de-prova de 10 cm de diâmetro e 20 cm de altura foram realizados para comparação com resultados de ensaios em corpos-de-prova maiores, realizados no novo equipamento. Os ensaios de módulo de resiliência foram conduzidos segundo o método de ensaio do DNIT, com algumas modificações para adequá-lo ao padrão internacional. Os ensaios triaxiais monotônicos e os cíclicos de deformações permanentes foram conduzidos tanto em multiestágios, quanto em estágio único de tensões. Os resultados obtidos foram interpretados segundo diversas teorias e modelos, obtendo-se parâmetros de resistência e de deformabilidade. Uma análise mecanística utilizando os parâmetros obtidos nos ensaios permitiu analisar o comportamento do material estudado como camada de pavimento. Conclui-se que o equipamento triaxial de grande porte atende as necessidades para as quais foi projetado, permitindo obter parâmetros para caracterização do comportamento de agregados graúdos e prever desempenho de pavimentos, quanto a deformações permanentes e ruptura por cisalhamento de camadas granulares.Unbound aggregates layers play an important role in the performance of thinly surfaced or unsurfaced pavements. In order to assess the strength-strain characteristics of soils and aggregates used in those layers, triaxial tests must be carried out on cylindrical specimens with diameter not smaller than 5 times the particle maximum size and height twice the diameter. Since Brazil National Roads Department allows using 2” aggregates in granular bases, specimens for triaxial tests should be at least 25 cm in diameter and 50 cm in height. All over the world there are only a few equipments for testing such specimens; and up to 2008 none of them in Brazil. Aiming at overcoming this deficiency and enhance the knowledge on the mechanical behavior of coarse aggregates, the objectives of research reported in this thesis were to develop a triaxial equipment capable of applying static, monotonic and repeated loadings on large specimens (25 cm x 50 cm) and perform and analyze the first tests. The design and assemblage of the equipment are describe, detailing its main components and the instrumentation, that included two load cells, three displacement transducers and two pressure transmitters. The first tests were carried out on specimens made of dense crushed aggregates, formerly used in APT test sections. Tests were also carried out on specimens with 10.0 cm diameter and 20.0 cm height, in order to compare their results to those of tests carried out in larger specimens tested in the new triaxial equipment. Resilient modulus tests were carried out according to the Brazilian standard, but some modifications were introduced to follow international patterns. Triaxial monotonic and repeated loading permanent deformation tests were carried out both in multiple stages and unique stage of stresses. The results were interpreted were calculated taking into account several theories and models, strength and strain parameters being obtained. A mechanistic analysis using parameters obtained in tests allowed analyzing the behavior of the studied aggregates making part of pavement layers. It is concluded the new triaxial equipment for large specimens fulfills the requirements that motivated its design and construction, making possible to obtain parameters for characterizing the behavior of coarse aggregates and estimating pavements performance regarding permanent deformation and shear failure of granular layers.
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Naskos, Nicolas A. "Quelques aspects du comportement mécanique de l'argile saturée, consolidée sous fortes pressions." Châtenay-Malabry, Ecole centrale de Paris, 1985. http://www.theses.fr/1985ECAP0002.
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Cette étude ne fait qu'avancer certaines hypothèses ou constatations concernant le rôle de la pression de consolidation sur le comportement mécanique des argiles saturées, en les validant expérimentalement
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Yadav, Ram Babu. "High-spin triaxial strongly deformed structures and quasiparticle alignments in 168Hf." Diss., Mississippi State : Mississippi State University, 2009. http://library.msstate.edu/etd/show.asp?etd=etd-07012009-213010.
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Bahda, Fatiha. "Etude du comportement du sable à l'appareil triaxial : expérience et modélisation." Phd thesis, Ecole Nationale des Ponts et Chaussées, 1997. http://tel.archives-ouvertes.fr/tel-00523153.
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Après avoir identifié expérimentalement les principaux traits de comportement du sable en petites et grandes déformations pour différents types de chargement, un diagramme de comportement des sables est proposé. Valable pour tout état initial de déposition, ce diagramme permet de bien définir les différentes zones de comportement, notamment de mieux évaluer le potentiel d'effondrement observé dans les sables lâches. En petites déformations, une forme d'anisotropie élastique de type isotropie transverse est mise en évidence grâce à un simple essai triaxial. Deux paramètres type paramètre d'état, nommés couple d'état, sont définis pour quantifier le comportement d'un matériau granulaire dans une condition initiale donnée, notamment sous consolidation isotrope ou anisotrope. Deux essais avec des échantillons ayant le même couple d'état présenteront un comportement similaire. Ces différents traits de comportement ont été formalisés par un modèle d'état critique. Il a été développé pour simuler le comportement des sols granulaires sous chargements monotones et cycliques. Une des priorités du modèle est de pouvoir simuler le comportement d'un sable lâche, moyennement dense et dense avec le même jeu et les mêmes valeurs de paramètres, en ne faisant varier que les conditions initiales qui contrôlent ces types de comportement, comme observé expérimentalement. L'originalité de ce modèle réside dans l'introduction du couple d'état et la considération d'un double mécanisme de plasticité dans un cadre d'élastoplasticité généralisée. Ce cadre a l'avantage de permettre une description simple des phénomènes observés expérimentalement sans suivre nécessairement le cadre rigide de la plasticité classique. Des simulations d'essais réalisés sur le sable d'Hostun rf ont permis de montrer que cette formulation reproduit bien le phénomène d'effondrement aussi bien en monotone qu'en cyclique. Toujours avec le même jeu de paramètres et en ne variant que la densité, des simulations concernant le même sable ont montré que le modèle reproduit d'une manière assez fidèle l'influence de la densité sur le comportement. D'autres simulations d'essais réalisés sur d'autres sables ont permis de valider le modèle pour des essais de mobilité cyclique et des essais drainés monotones et cycliques.