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 16 of 16 for “"Time-Dependent Response"”.
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Subcritical time-dependent response of Berea sandstone
… disturbances within the subsurface layers. The response of rocks to these disturbances unfolds over extended periods, sometimes spanning months to years, giving rise to time-dependent deformation. Laboratory- and field-scale observations indicate that such time-dependent behavior can lead to …
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Time-dependent response of flat plate structures under high sustained load
… removal of one member. However, the overall time-dependent response of the member and how that response can lead to structural collapse is unknown. This research aims to understand the impact of high sustained loads on the evolution of structural collapse in reinforced concrete flat-plate …
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Measuring and Modeling the Time-Dependent Response of Cementitious Materials to Internal Stresses
… autogenous and drying shrinkage as mechanical responses to internally applied stresses. In this thesis, previous modeling work is extended such that autogenous shrinkage of cement paste is considered as a viscoelastic response to internally applied stresses. In addition, concrete shrinkage is …
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Radiation and temperature effects on the time-dependent response of T300/934 graphite/epoxy
A time-dependent characterization study was performed on T300/934 graphite/epoxy in a simulated space environment. Creep tests on irradiated and non-irradiated graphite/epoxy and bulk resin specimens were carried out at temperatures of 72 °F and 250 °F. Irradiated specimens were exposed to dosages …
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The influence of time-dependent material behavior on the response of sandwich beams
To study the influence of the time-dependent behavior of various materials being considered for use in orbiting precision segmented reflectors, simple sandwich beam models are developed. The beam models included layers representing face sheets, core and adhesive. The issue of time-dependency is …
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Viscoelastic response of wound polymer cord with multiple filament cross-sections
… by George Costello, is modified to include the time-dependent response of twisted polymer fibers under an applied axial load. This modified theory incorporates the cord material's response by utilizing the Wiechert model and the Schapery collocation method. The geometric effects are then …
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Viscoelasticity of Articular Cartilage and Ligament: Constitutive Modeling and Experiments
… to capture both the short-term and long-term time-dependent response of these tissues with less difficulty in material characterization process. Due to the lack of the desired tensile experimental results on articular cartilage, the mechanical behavior of this tissue was also examined …
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Soft hydrated sliding interfaces as complex fluids
… behavior characterized by weakly or strongly time-dependent response and thixotropy-like hysteresis. Tribo-rheometry is particularly suited to uncover the lubrication mechanisms of complex interfaces such as are formed with hydrated hydrogel surfaces and biological surfaces.
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Pseudospin transfer torques and the effect of disorder in semiconductor electron bilayers
… tunneling I-V characteristics, and can lead to time-dependent response to a dc bias voltage. In addition, we study the eff ects of disorder on the interlayer transport properties of disordered semiconductor bilayers. We find that the addition of material disorder to the system affects interlayer …
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Earthquakes, groundwater and surface deformation : exploring the poroelastic response to megathrust earthquakes
… interesting phenomena involving the poroelastic response to earthquakes along the way. Chapter 1 sets up an elastic inverse problem used to derive the initial slip condition. We formulate an adjoint-based inversion methodology to solve for the initial condition of the coupled poroelastic forward …
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Rheology Of Cross-Linked Polymers And Polymer Foams: Theory And Experimental Results
<p>Typical polymers have a time-dependent response to loading which results in stress relaxation or creep. Models using springs/dashpots or Volterra integrals are capable of predicting the material response, but place little or no emphasis on the reasoning behind the response. This research …
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Evaluating the Mechanical Properties and Long-Term Performance of Stabilized Full-Depth Reclamation Base Materials
… base materials varied significantly over time. These changes were attributed to curing after construction, seasonal effects, and subgrade moisture. The structural capacity of the pavements improved irrespective of the stabilizing agent used. Rutting was higher for the foamed asphalt and …
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Evaluating the Mechanical Properties and Long-Term Performance of Stabilized Full-Depth Reclamation Base Materials
… base materials varied significantly over time. These changes were attributed to curing after construction, seasonal effects, and subgrade moisture. The structural capacity of the pavements improved irrespective of the stabilizing agent used. Rutting was higher for the foamed asphalt and …
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Wind-evaporation feedback, angular momentum conservation, and the abrupt onset of monsoons
… the weakest forcings. These results hold for the time-dependent response to seasonally varying forcings: for forcings of intermediate strength, WISHE produces an abrupt onset of solsticial flow when only a linear response would otherwise occur, while for strong forcings WISHE shifts the abrupt …
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A computational neuromuscular model of the human upper airway with application to the study of obstructive sleep apnoea
… breathing-induced loading is investigated. The response of the various muscles of the tongue to the complex loading developed during breathing is determined, with a particular focus being placed to that of the genioglossus. It is demonstrated that, when a time-dependent loading is applied to the …
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Mechanical behaviour of Clay-Shales (Argille Scagliose) and implications on the design of tunnels
… particular attention to the development of large time-dependent deformations. These deformations may develop either during the construction stage, causing instabilities of the tunnel face and unsafe working conditions, or remain hidden during the “short-term”, thus leading to complex problems when …