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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 25 for “"in-plane stress"”.
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Detection of in-plane stress waves with Polyvinylidene Fluoride (PVDF) sensors
<p>Polyvinylidene Fluoride (PVDF), a piezoelectric polymer, is an excellent stress sensor. The objective of this research is to investigate the application of the PVDF sensors for detection of in-plane stress waves in 31 and 32 modes. This was achieved by focusing on aspects of PVDF sensing related …
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Hafnium Nitride(x): Phase Composition, Microstructure, and Physical Properties of Epitaxial and Polycrystalline Layers
The phase-compositions obtained in HfNx grown on SiO 2 at 350°C are alpha-Hf:N (x ≤ 0.6); multiphases (0.6 ≤ x ≤ 0.9); delta-HfN single-phase (0.9 ≤ x ≤ 1.3); and mixtures of delta-HfN and higher nitrides (x ≥ 1.3). HfNx layers with 0.9 ≤ x ≤ 1.2 grown under mild …
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An exact plane-stress solution for a class of problems in orthotropic elasticity
An exact solution for the stress field within a rectangular slab of orthotropic material is found using a two-dimensional Fourier series formulation. The material is required to be in plane stress, with general stress boundary conditions, and the principle axes of the material must be parallel to …
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Thermo-mechanical stress measurement and analysis in three dimensional interconnect structures
Three-dimensional (3-D) integration is effective to overcome the wiring limit imposed on device density and performance with continued scaling. The application of TSV (Through-Silicon Via) is essential for 3D IC integration. TSVs are embedded into the silicon substrate to form vertical, electrical …
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Transport and damage in hydrated coatings – a model soft active composite material
… and encompass a wide variety of materials including lithium ion battery anodes and biological matter. Four interrelated fundamental processes – transport, volume change, stress, and damage – are present in active materials. This thesis explores the interconnection of these processes using …
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Sintering of glass films on rigid substrates studied by optical techniques
… measurement techniques were devised to determine the shrinkage profiles of the free and constrained films and in-plane stress in the constrained films. These films were prepared from slurries of the powder by tape casting. Sintering was carried out isothermally in a hot stage between 665°C and …
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An investigation of methods for determining notch root stress from far field strain in notched flat plates.
… flat plate specimens have been tested to examine Neuber's equation and other relations with respect to their application in the determination of stresses in the plastic range at the notch root when the far field strain is known. A nonlinear finite element solution has also been obtained for …
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A programming approach to the numerical analysis of elasto-plastic continua
The application of a kinematic minimum principle involving a continuous functional subject to inequality constraints is described for the incremental analysis of elasto-plastic continua. A simple algorithm is used for solution of the resulting mathematical programming problem. The formulation is …
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A programming approach to the numerical analysis of elasto-plastic continua
The application of a kinematic minimum principle involving a continuous functional subject to inequality constraints is described for the incremental analysis of elasto-plastic continua. A simple algorithm is used for solution of the resulting mathematical programming problem. The formulation is …
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Pulmonary Valve Replacement
… (SPVR) to treat pulmonary valve disorders in patients with prior congenital heart surgery. Edwards Sapien 3 valve is a bioprosthesis originally designed for the aortic position but has been used off-label in native right ventricular outflow tract (RVOT). It is currently under clinical trial …
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Residual Stress Development and Effect on the Piezoelectric Performance of Sol -Gel Derived Lead Zirconate Titanate (Pzt) Thin Films
Additionally two patterning methods, traditional chemical wet-etching and a novel soft lithographic technique, are explored as a means to reduce residual stress within film features. For the soft lithographic technique, film features are created by selective film cracking, a result of poor …
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Analysis of shear test methods for composite laminates
An elastic plane stress finite element analysis of the stress distributions in four flat test specimens for in-plane shear response of composite materials subjected to mechanical or thermal loads is presented. The shear test specimens investigated include: slotted coupon, cross beam, Iosipescu, and …
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Uma formulação de elementos de contorno para análise de vibrações livres
… analysis of free vibrations of elastic bodies in plane stress or plane strain. The main characteristic of this method is the transformation of the inertial domain integral into equivalent boundary integrals, by employing special interpolation functions to approximate the accelerations within …
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Failure strength and mechanism of composite laminates under multiaxial loading conditions
… behavior of orthotropic G-10 glass fiber reinforced composite laminates in an in-plane stress state has been conducted. Different types of biaxial specimens and associated test fixtures were developed and employed in the study. Standard IITRI specimens were used to determine tensile and …
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Determinação da fluência do concreto e do coeficiente de Poisson diferido em um estado de tensões de compressão bi-axial
… and analyse the first results of direct strain measurement in the concrete of the test slab (prestressed slab in two directions) of the Laboratório de Estruturas do Centro de Tecnologia da Universidade Federal do Rio de Janeiro. The purpose of the work is to observe the creep of the concrete …
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Development of a Progressive Failure Finite Element Analysis For a Braided Composite Fuselage Frame
… fabricated from a textile composite are tested in axial compression to study the modes of failure with and without local buckling occuring.The textile preform architecture is a 2x2, 2-D triaxial braid with a yarn layup of [0 deg 18k/+-64 deg 6k] 39.7% axial. The preform was resin transfer molded …
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The time-temperature behavior of graphite epoxy laminates
An in-depth study on the time-temperature behavior of epoxy based continuous and elastic fiber reinforced composite materials and the feasibility of using the time-temperature analogy as an accelerated characterization method to predict the long-term behavior are presented. This is a two-pronged …
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High-Resolution Characterization of Micro-Scale Crack Tip Fields in Zirconium
Zirconium (Zr) alloys are widely used in nuclear reactors as structural core components owing to their low thermal neutron absorption cross-section and adequate mechanical and corrosion properties. To ensure the sustainable design and safe operation of nuclear reactors, understanding the failure …
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Thermoelastic stress analysis of laminated composite materials
In this work thermoelastic stress analysis (TSA) is used to obtain quantitative stress/strain data from a variety of multi-directional laminated composites. In order to interpret the thermoelastic signal correctly the source of the thermoelastic response has been investigated in detail. In this …
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On the Rumpling Instability in Thermal Barrier Systems
"Thermal barrier coatings (TBCs) are protective multi-layered metal-ceramic coatings used in hot sections of jet engines and gas turbines. The TBCs are composed of a superalloy substrate, an intermediate metallic bond coat (BC) and a ceramic topcoat. The TBCs are beset by reliability problems …
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