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 62 for “"Time-temperature superposition"”.
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Long-term creep modeling of wood using time temperature superposition principle
… were developed from short-term data using the time temperature superposition principle (TTSP) for kiln-dried southern pine loaded in compression parallel-to-grain and exposed to constant environmental conditions (~70°F, ~9%EMC). Short-term accelerated creep (17 hour) and recovery (35 hour) data …
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Development of tension and compression creep models for wood using the time-temperature superposition principle
… for wood in tension and compression using the Time-Temperature Superposition Principle (TTSP). The principle states that the long-term response of a polymer at lower temperature is equivalent to the short-term response at a higher temperature. Accelerated creep tests were conducted in tension …
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Viscoelastic characterization of angle ply advanced composites
Time dependent properties of angle ply laminated Boron/Epoxy and Graphite/Epoxy fiber controlled composites were investigated. The main objective of this study was to develop a technique to establish interconversion of different test results using appropriate viscoelastic theory to formulate an …
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The nonlinear viscoelastic behavior of adhesives and chopped fiber composites
… procedures of Schapery in conjunction with the time-temperature superposition principle to obtain a time-stress-temperature surface to define failure.
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The accelerated characterization of viscoelastic composite materials
… the accelerated characterization techniques of Time Temperature Superposition and Time Temperature Stress Superposition are treated in detail. An experimental procedure for applying the latter to composites is given along with results obtained on a particular T300/934 graphite/epoxy. The …
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Characterization of UHMWPE Laminates for High Strain Rate Applications
… of polymers, the properties of UHMWPE are time-dependent. It is desired by research sponsors to know the properties of the material at high strain rates, in order to simulate the use of these materials in computer models. Properties believed to be significant which are investigated in this …
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Time, temperature and frequency viscoelastic behavior of commercial polymers
… on characterizing the effects of physical aging, temperature, and frequency. The procedure for finding the shift rate, mu, is based on Struik's protocol. Time-temperature superposition (TTSP) of short-term data, at different temperatures, was done. Effective Time Theory (ETT) is used to find the …
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Aging model for commercial polymers
… of sewer pipes. The analysis uses the effective-time theory and time-temperature superposition (TTSP) methods proposed by Struik, as well as variations of these methods, as proposed by Chai and McCrum, Guerdoux et al. and others. The creep data generated by this study show that the time-dependent …
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Characterization and Response of Thermoplastic Composites and Constituents
… and their constituents. UHMWPE, as a polymer, is time and temperature dependent. Using time-temperature superposition (tTSP), the constituent properties are studied as a function of strain rate. Properties that are believed to be significant are fiber tensile properties as a function of strain …
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Effects of Long-Term Creep on the Integrity of Modern Wood Structures
… yellow-poplar, and Parallam™ samples at temperatures ranging between 20 and 80° C and at 6, 9 and 12% moisture content. The principle of time-temperature superposition was applied to form a master curve that extended for a maximum of 2 years. The horizontal shift factors followed an …
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Wood Material Behavior in Severe Environments
… additional knowledge is needed are: the high temperature equilibrium moisture content (EMC) behavior and the moisture dependent softening behavior. EMC data was collected and desorption isotherms were generated for mature and juvenile wood of aspen, loblolly pine and yellow-poplar at 50 and …
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Understanding the effect of nanofillers on the properties of polypropylene and glass fiber/polypropylene multiscale composites
… between the tensile modulus, glass transition temperature and the amount of constrained phase, as assessed through tensile and DMA analyses, revealed the presence of a secondary reinforcing mechanisms, which, concurrently to the primary stiffening effect of the high modulus filler, contributes …
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Characterization and modeling of the effect of environmental degradation on flexural strength of carbon/epoxy composites
… the Arrhenius principles adapted to the TTS (Time Temperature Superposition) to measure degradation of carbon-fiber/epoxy composite under hygrothermal exposure and applied tensile stress. The hygrothermal conditions capture the synergistic effects of field exposure and extreme temperatures, …
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Analytical Modeling for Sliding Friction of Rubber-Road Contact
… conditions. Rubber properties are highly temperature dependent. Temperature model developed based on heat diffusion relation is integrated to consider the effects of temperature rise due to frictional heating. Model results are validated with theoretical results of literature. Simulation …
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Analysis and Modeling of the Mechanical Durability of Proton Exchange Membranes Using Pressure-Loaded Blister Tests
… of Gore-Select® series 57 over a range of times, temperatures, and loading histories. Ramped pressure tests are used with a linear viscoelastic analog to Hencky's classical solution for a pressurized circular membrane to estimate biaxial burst strength values. Biaxial strength master curves …
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Design of Cold-In-Place Recycling using Superpave gyratory compactor
… master curves were developed for by using time-temperature superposition principle. Furthermore, the rutting resistance of all the CIR mixtures were also evaluated in term of the flow number.
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Physical, Mechanical and Chemical Aging of Polyurea Nanocomposites
… effects of various environmental factors such as temperature, humidity, light, etc. on the performance of composite materials is the second challenge addressed in this research work. Selective composites are subject to hygrothermal cycling and ultraviolet (UV) radiation and stabilities studies for …
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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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Modeling the High Strain Rate Tensile Response and Shear Failure of Thermoplastic Composites
… from 10^-4/s to 10^-1/s and shifted using the time-Temperature Superposition Principle (tTSP) to strain rates of 10^-4/s to 10^6/s. Other fiber properties are obtained from the same tests, but are assumed to be deterministic. Matrix properties are also assumed to be deterministic and are …
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Comparison of Creep Compliance Master Curve Models for Hot Mix Asphalt
… is used to predict HMA thermal cracking at low temperature and permanent deformation at high temperatures. There are several experimental methods to measure the creep compliance. Two of these methods were used in this thesis; uniaxial compressive and indirect tension (IDT) creep compliance. The …
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