Global ETD Search
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 73 for “"Viscoelastic behavior"”.
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A study of biaxial viscoelastic behavior
… to investigate the feasibility of determining a viscoelastic stress-strain law for two (or three) dimensional stress conditions by means of one dimensional tests. The conclusions are based upon comparison of theory and experiment for a creep test of a lead plate, subjected to biaxial tension. The …
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Viscoelastic behavior of water-blown flexible polyurethane foams
… of this dissertation was on characterizing the viscoelastic behavior of a set of four flexible slabstock water-blown polyurethane foams with varying hard segment content as well as solid plaques made from these foams. Three viscoelastic tests; tensile stress relaxation, compression load …
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Time, temperature and frequency viscoelastic behavior of commercial polymers
… involves an experimental investigation of creep behavior of commercial polymers used as encased liners in deteriorated sewer pipelines with emphasis on characterizing the effects of physical aging, temperature, and frequency. The procedure for finding the shift rate, mu, is based on Struik's …
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Viscoelastic behavior and wear of polymeric liners for joint replacement
Thesis (M.S.)--Michigan State University. Chemical Engineering, 2010
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Influence of calcium-(alumino)-silicate-hydrate nanostructure on viscoelastic behavior
Viscoelasticity in concrete has been studied since the early 20th century with continuously advancing technology and methods. Currently, calcium-silicate-hydrate (C-S-H) is thought to be the phase responsible for viscoelasticity in concrete. Advances in small-scale mechanical testing in the past …
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Nonlinear Viscoelastic Behavior of Ligaments and Tendons: Models and Experiments
… of ligaments and tendons. The mechanical behavior of bundles of collagen fibers which form ligaments and tendons was investigated. Axial stress-stretch data and stress relaxation data at different axial stretches were collected by testing rat tail tendon fascicles. The experimental results …
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The nonlinear viscoelastic behavior of adhesives and chopped fiber composites
The viscoelastic behavior of a chopped glass fiber/polyester sheet molding compound (SMC-25) and of a modified epoxy adhesive (Metlbond 1113-2) as determined by creep and creep recovery tests is presented. A nonlinear viscoelastic characterization method of Schapery is presented and applied to the …
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The effect of residual thermal stresses on the viscoelastic behavior of adhesively bonded joints
… properties and the corresponding in-situ behavior has led to numerous adhesive test geometries. The current study was an attempt to predict the nonlinear viscoelastic response of an adhesive in-situ using properties obtained from a pure shear test geometry. Four candidate adhesive test …
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The Effects of Early-Age Stress on the Elastic and Viscoelastic Behavior of Cement Paste
The viscoelastic behavior of concrete, nearly completely attributable to changes in properties in the cement paste, is an ongoing area of research with the objective of avoiding unpredictable response and potentially failure of concrete structures. This research explores the elastic and …
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Characterization and numerical simulation of the microstructural and micromechanical viscoelastic behavior of oil sands using the discrete element method
… a need to develop valid models that capture the behavior and performance of oil sands under these loads. Particle-based physics methods, such as the discrete element method (DEM) can provide useful insight into the micromechanical and microstructural behavior of oil sands. This research is a …
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Modeling of the Aging Viscoelastic Properties of Cement Paste Using Computational Methods
Modeling of the time-dependent behavior of cement paste has always been a difficulty. In the past, viscoelastic behavior of cementitious materials has been primarily attributed to the viscoelastic properties of C-S-H components. Recent experimental results show that C-S-H may not exhibit as much …
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Exploring the Black Space of Compressive and Shear Modulus
… modulus is a standard test used to determine the viscoelastic behavior of asphalt pavement materials, with the standard analysis generating a Master Curve. One alternative to the master curve approach is a Black Space diagram, which is a rheological plot that can delineate either dynamic modulus …
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Dynamic mechanical analysis of magnetic tapes at ultra-low frequencies
… effects of temperature and frequency on the viscoelastic behavior of magnetic tapes, using a custom, ultra-low frequency, dynamic mechanical analyzer. The long-term mechanical and thermal properties of magnetic tapes can be simulated using high temperature and low frequency dynamic mechanical …
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Nonlinear viscoelastic characterization of structural adhesives
Measurements of the nonlinear viscoelastic behavior of two adhesives, FM-73 and FM-300, are presented and discussed. Analytical methods to quantify the measurements are given and fitted into a framework of an accelerated testing and analysis procedure. The single integral model used is shown to …
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Process-induced viscoelastic residual stress analysis of graphite/epoxy composite structures
In this research the effect of viscoelastic behavior of thermoset matrix fiber-reinforced composites on process-induced residual stresses was investigated. The material selected for study was AS4/3501-6, a commercial prepreg system manufactured by Hercules, Inc. To investigate the cure-dependent …
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Estimation of Elastic and Damping Characteristics of Viscoelastically Constrained Carbon Strands
… uses composites in a fabric form that displays viscoelastic behavior. The viscoelastic behavior is attributed to energy dissipation because of the shear stresses between the various fibrous strands that are kept in place by constraining viscoelastic layers. This type of vibration control falls …
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Design tools for linear viscoelastic fluids
… materials – materials that exhibit linear viscoelastic behavior – for design. This work develops the framework necessary to incorporate linear viscoelastic materials into the designer's toolbox. First, we think deeply about ways to describe linear viscoelastic behavior for development of …
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Modeling viscoelastic cellular materials for the pressing of wood composites
… a flakeboard during pressing, interacts with the viscoelastic behavior of individual flakes to influence density gradient formation and in situ flake properties. The specific objectives: l. To use observed changes in the temperature and gas pressure of the internal environment of panels during the …
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The Effect of Catalyst Layer Cracks on the Mechanical Fatigue of Membrane Electrode Assemblies
… cyclic pressurization pattern, which affects the viscoelastic behavior of the membranes, has a significant effect on the relative lifetime of the MEA. To investigate this behavior, pressure-loaded blister tests were performed at 90 °C to determine the biaxial fatigue strength of Gore-Primea® …
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