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 37 for “"Crystal Plasticity"”.
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Rate independent crystal plasticity
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1995.
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Crystal plasticity due to slip and twinning
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1998.
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Incorporating Grain Size Effects in Taylor Crystal Plasticity
… method to incorporate grain size effects into crystal plasticity is presented. The classical Hall-Petch equation inaccurately predicts the macroscopic yield strength for materials with non-equiaxed grains or materials that contain unequal grain size distributions. These deficiencies can be …
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Modeling dislocation density evolution in continuum crystal plasticity
… the singly most important material defects in crystal plasticity, and although dislocation mechanics has long been understood as the underlying physical basis for continuum crystal plasticity formulations, explicit consideration of crystallo- graphic dislocation mechanics has been largely …
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Mechanism-based constitutive modeling of L1₂ single-crystal plasticity
Ni3Al, an L12 structure intermetallic crystal, is the basic composition of the [gamma]' precipitates in nickel-based superalloys and is a major strengthening mechanism contributing to the superalloys' outstanding high-temperature mechanical properties. Many L12-structure crystals present unusual …
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Towards mechanism-based constitutive modelling of L1₂ crystal plasticity
A single-crystal plasticity model of the L12 structure intermetallic compound Ni3Al is developed, in light of recent theoretical developments and experimental evidence. Computational results show that the model is capable of predicting the major anomalous mechanical behaviors of L12 structures, …
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An investigation into aspects of rate-independent single crystal plasticity
… 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 heuristic and their …
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On the mechanics of the hydrogen interaction with single crystal plasticity
… of hydrogen on the mechanical behavior of single crystals. A macroscopic crystal plasticity model is formulated based on the fundamentals of the hydrogen-dislocation interactions. Various hardening evolution equations are investigated and employed in a physically-based model. The presence of …
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Single-crystal plasticity at finite strains: a computational investigation of hardening relations
… the system of equations that describe single-crystal viscoplasticity under finite strains. The second objective is to use the computer code that is developed to examine three hardening laws that have been proposed. The first is an isotropic hardening law. The second is a hardening law that is …
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Understanding the deformation mechanisms in nanostructured metals by a novel discrete crystal plasticity finite element model
… simulations indicate that dislocation-mediated plasticity in nanostructured metals and alloys is significantly different from that in their coarse-grained counterparts. Therefore, this dissertation focuses on the exploration of the deformation mechanisms in nanostructured metals via crystal …
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Exploration of incompatibility in Al-Li alloys using high energy diffraction microscopy and a crystal plasticity model
… Energy Diffraction Microscopy (HEDM) and polycrystal plasticity simulations to study the local evolution of lattice strains to gain insight into the development of incompatibility. The identification of factors that initiate and drive delamination fracture, such as the development of shear and …
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On the role of lattice defects interactions on strain hardening: A study from discrete dislocation dynamics to crystal plasticity modelling
… dislocation dynamics (DDD) simulations and crystal plasticity laws informed by DDD. At the scale of lattice defects, a DDD tool enabling simulations on any crystalline structure is developed to model dislocation-dislocation, dislocation-twin and dislocation-particles interactions. The tool …
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Continuity in Rigid Viscoplastic Flow
Classical plasticity models evolve state variables in a spatially independent manner through (local) ordinary differential equations, such as in the update of the rotation field in crystal plasticity. This approach emanates from how the deformation has been described, e.g. the multiplicative …
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Dislocation -Defect Interactions in Irradiated and Quenched FCC Metals
… the basis for a new dispersed-barrier hardening crystal plasticity model that predicts the important features of the mechanical response of irradiated materials.
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Hierarchical multiscale modeling of Ni-base superalloys
… the model are used as inputs to a grain scale crystal plasticity model in a bottom-up fashion. The crystal plasticity model incorporates microstructure attributes by homogenization. A major task of the present work is to link the crystal plasticity model, informed by the phase field model, to …
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On a class of strain gradient plasticity theories : formulation and numerical implementation
… strain-gradient theories for isotropic and crystal plasticity. The following four theories were developed and numerically implemented: * A one-dimensional theory to understand the basic nature of strain gradient theories; * A small deformation crystal plasticity theory; * A small deformation …
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Microstructure-informed modeling of hydrogen diffusion in zirconium polycrystals
… of nuclear pressure tubes. This thesis uses a crystal plasticity finite element model coupled with diffusion equations to study the effects of localized deformation at the grain scale on the hydrogen diffusion and hydride precipitation in zirconium. Attention is given to the effects of crystals …
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Investigating Dislocation Behavior in High Entropy Alloys Using Atomistic Simulations
… and tune the mechanical properties and crystal plasticity of the alloys, it is necessary to investigate the dislocation behavior[15]. The NiCoCr system is reported to have a single-phase face-centered cubic (FCC) crystal structure with enhanced mechanical properties compared to …
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Exploring the Stochastic Performance of Metallic Microstructures With Multi-Scale Models
… material properties are directly related to the crystallographic structure at the micro-scale. Furthermore, microstructural uncertainties arising from experiments and computational methods propagate on the material properties used for designing aircraft components. Therefore, multi-scale modeling …
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