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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

O estudo das propriedades elásticas de materiais compósitos : um tratamento matemático /

Pacheco, Tiago Levi January 2019 (has links)
Orientador: Renata Zotin Gomes de Oliveira / Resumo: Este trabalho concentra-se no estudo do comportamento elástico de materiais através da análise das matrizes de rigidez e flexibilidade de estruturas elementares. Baseado em conceitos da disciplina Resistência dos Materiais e nas propriedades elásticas dos materiais são apresentadas e demonstradas relações matemáticas que refletem as associações entre as tensões normais e de cisalhamento atuantes e as deformações e distorções decorrentes. Essas relações são ilustradas computacionalmente, através do software Geogebra. Transformações de coordenadas possibilitam a determinação de tensões em planos diferentes dos originais de forma analítica ou gráfica. Estes conceitos são aplicados a materiais compósitos ortotrópicos sujeitos a carregamento plano, configuração característica de uma lâmina de material compósito empregada em estruturas mais complexas, possibilitando a determinação das propriedades elásticas de uma lâmina em direções diferentes das chamadas direções principais, alinhadas ou ortogonais à direção das fibras. / Abstract: This essay focuses on the study of the elastic behavior of materials through the analysis of the stiffness and flexibility matrices of elementary structures. Based on the concepts of the Material Resistance discipline and the elastic properties of the materials, mathematical relationships are presented and demonstrated that reflect the associations between the acting normal and shear stresses and the resulting deformations and distortions. These relationships are computationally illustrated through Geogebra software. Coordinate transformations allow the determination of stresses in different planes of the originals in an analytical or graphical way. These concepts are applied to orthotropic composites subjected to flat loading, characteristic configuration of a composite material blade used in more complex structures, making it possible to determine the elastic properties of a blade in different directions of the so-called main directions, aligned or orthogonal to the direction of the fibers. / Mestre
2

Sypné vlastnosti jemných partikulárních materiálů jako funkce vybraných látkových parametrů / Bulk properties of fine particulate solids as the function of the selected material parameters.

Slanina, Ondřej January 2014 (has links)
The theoretical part of the thesis focuses on the description of particulate materials and their mechanical behaviors with a focus on flow properties. Great emphasis is placed on measuring the shear properties using a Jenike shear machine, on the correct procedure for standardized measurement and evaluation using Mohr's circles. The theoretical part focuses on the characterization of particulate matter using a variety of methods available, such as visual, separation, sedimentation, surface methods and methods of scanning field and flow. The practical part is focused on the determination of flow characteristics and surface finishing of finely ground limestone Omyacarb VA with various grain sizes. The surface was modified using stearic acid and calcium stearate. Attention was paid to the influence of the concentration of surface-regulating substances on the flowability of the material. The flowability of commercially supplied material was compared with lab modified materials and the determination of the theoretical content of stearic acid or calcium stearate was accomplished. Shear properties were measured using the Jenike shear machine. The material was further tested by laser diffraction and SEM with EDS particle surface analysis and elemental surface mapping.

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