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 36 for “"Rate-Independent"”.
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Rate independent crystal plasticity
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1995.
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An investigation into aspects of rate-independent single crystal plasticity
… is to compare various algorithms for rate-independent single-crystal plasticity restricted to the infinitesimal case. The rate-independent case presents significant numerical challenges such as ill-conditioning and non-smoothness. The majority of the algorithms in the literature are …
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Plasticity and non-simple materials
… The thermodynamic relations of conventional rate-independent plasticity and various classes of second-deformation-gradient plasticity are derived within the context of a theory with internal variables using the ""Coleman-Noll"" procedure. Models of conventional and gradient-dependent, …
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Development of Elastic Resistive Force Theory & Applications to Uprooting
… present. While these phenomena can be accurately modeled via discrete element methods and continuum models, this accuracy comes at a great computational cost, especially for large systems. Granular Resistive Force Theory (RFT) is a reduced-order, rateindependent model that has been shown to …
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Continuum Mechanics of Duhem’s Approach to Hysteresis
… Duhem model. In a conser-vative system, the time rate of the dependent variable (e.g., stress) is related to the time rate of the independent variable (e.g., strain) through the second derivative of the Helmholtz free energy. To account for hysteresis, Duhem added a term featuring a continuous …
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Design and analysis of transient nonlinear coupled systems
… formulations are particularized to the case of rate-independent elasto-plasticity. Analytic sensitivities for weakly coupled thermo-elasto-plastic systems are computed with the finite element method by implementing the direct differentiation method.
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Thermostated Kac models
… the Gabetta-Toscani-Wennberg (GTW) metric, at a rate independent of N. When m < N , the exponential rate of approach to equilibrium in L2 is shown to behave as m/N for N large, while the relative entropy and the GTW distance from equilibrium exhibit (at least) an "eventually exponential” decay, …
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South Africa's debt sustainability: A multi-factor approach
… in arguing that increasing debt can be tolerated for states that have a level of monetary sovereignty. This paper concludes that South Africa has a high degree of monetary sovereignty due to factors including its flexible exchange rate, independent and credible central bank, high level of …
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Modeling the United States Unemployment Rate with the Preisach Model of Hysteresis
… is one that exhibits path dependent but rate independent memory. Hysteresis can be observed physically through the magnetization of a ferromagnetic material. In order to mathematically describe systems with hysteresis, we use the Preisach model. A discussion of the Preisach model is given …
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Numerical analysis of plastic deformation in metal-ceramic nanolayers during cyclic indentation
… carbide (SiC) thin films on a silicon (Si) substrate is indented by a conical diamond indenter. In this study, both rate-independent and rate-dependent plasticity models are considered. It is found that, in the multilayered material plastic deformation in the Al layers continues to occur upon …
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A Dislocation-Based Constitutive Model for Hydrogen-Deformation Interactions and a Study of Hydrogen-Induced Intergranular Fracture
… results. The first model creates a continuum, rate dependent plasticity model that incorporates the effect of hydrogen on dislocation generation, motion, and annihilation; the transient motion of hydrogen through the material is considered in a complete thermodynamic framework which determines …
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Characterization of Delamination in 2099-T861 Aluminum-Lithium
… Many of the experimental observations, such as rate insensitivity and crystallographic orientation, were incorporated into a cyclically stable crystal plasticity framework with rate independent kinematic hardening. It was hypothesized that texture lead to interface stresses that could not be …
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A dislocation-based constitutive model for hydrogen—deformation interactions and a study of hydrogen-induced intergranular fracture
… results. The first model creates a continuum, rate dependent plasticity model that incorporates the effect of hydrogen on dislocation generation, motion, and annihilation; the transient motion of hydrogen through the material is considered in a complete thermodynamic framework which determines …
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Nonlinear probabilistic finite element modeling of composite shells
… finite element formulation, employing a degenerated 3-D laminated composite shell element with the full Green-Lagrange strains and first-order shear deformable kinematics, forms the modeling foundation. The first-order second-moment technique for probabilistic finite element analysis of random …
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Shuttlebox Self-Stimulation Behavior Following Intracerebral Microinjections of Morphine Into the Ventral Tegmental-Substantia.
… of morphine have been shown to increase the rate at which rats will lever-press for electrical brain stimulation as well as decrease the current intensity required for this self-stimulation. In the shuttlebox paradigm, the animal crosses from one side of the case to the other in order to turn …
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Parameter Identification for the Preisach Model of Hysteresis
Hysteresis, defined as a rate independent memory effect, is a phenomenon that occurs in many physical systems. The effect is sometimes desired, sometimes a nuisance, sometimes catastrophic, but in every case we must understand hysteresis if we are to better understand the system itself. While the …
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Hydrothermal synthesis of zinc oxide nanowire arrays for photovoltaic applications
… can be grown vertically aligned from a substrate using hydrothermal synthesis, a low-cost, scalable process that is compatible with many semiconductor processing techniques. However, precise control over nanowire array dimensions such as nanowire spacing, diameter, length, and alignment, …
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Facilitating the Clinical Translation of Flash Radiotherapy Through Dosimetry Development and Beam Parameter Optimization
… Recently, ultra-high dose-rate (UHDR) RT (mean dose rates ≥40 Gy/s for a total duration of ≤200 ms) has been reported to selectively spare normal tissues and organs while maintaining an isoeffective tumoricidal effect compared to conventional (CONV) dose rate RT in a variety …
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Experimental investigation and constitutive modeling of metallic honeycombs in sandwich structures
… and numerical results, a finite-strain rate-independent orthotropic constitutive model for metallic honeycombs has been formulated and implemented into commercial finite element software. The good agreement of the model predictions with the experimental results encourages the use of this …
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