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Showing 1 to 16 of 16 for “"Dislocation Dynamics"”.
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CONTINUUM DISLOCATION DYNAMICS MODELING OF THE DEFORMATION OF FCC SINGLE CRYSTALS
A continuum dislocation dynamics model was developed for simulation of the deformation of Face Centred Cubic (FCC) single crystals. In this model, dislocations are described by a set of vector fields, one per slip system, whose evolution is governed by curl-type kinetic equations describing the …
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Co-evolution of microstructure and dislocation dynamics in InGaP/GaP : engineering high quality epitaxial transparent substrates
… fields and dominate the microstructure. causing dislocation pinning and escalation. Branch defects occur later in growth with increasing temperature; however, they are stronger when formed at higher temperatures. Branch defects do not appear to be directly related to other co-existing …
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Development of advanced numerical algorithms for kinetic and dynamic simulations of irradiated systems : kinetic Monte Carmelo and dislocation dynamics
… Approach, namely, kinetic Monte Carlo (kMC) and Dislocation Dynamics (DD). The first one aims to describe the diffusion and accumulation of de¬fects created in Radiation Damage, and the second follows the evolution of an ensemble of dislocations responding under some set of external loading …
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On the role of lattice defects interactions on strain hardening: A study from discrete dislocation dynamics to crystal plasticity modelling
… between predictions obtained by discrete 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 …
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Fatigue crack growth (FCG) modeling in the presence of nano-obstacles
A combination of molecular dynamics and dislocation dynamics simulations is performed to model fatigue crack growth (FCG) in a nano-twinned nickel single crystal. Molecular dynamics simulations are employed to investigate the irreversible interaction of crack-tip emitted dislocations with …
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Plasticity as a depinning phase transition
… phase transition employing a discrete dislocation dynamics (DDD) model and a phase eld crystal (PFC) model in two dimensions. Below a critical ( ow) stress, the dislocations are pinned/jammed within their glide plane due to long-range elastic interactions and the material exhibits …
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Simulação experimental de emissão acústica
… generation is proposed, based on the study of dislocation dynamics of Hirth and Lothe.
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Quantifying Dislocation Microstructures
… work, we reconstructed and full characterized a dislocation microstructure that formed during an in situ micro-cantilever beam experiment. Based on this information, we were then able to infer how the dislocations propagated from the notch into the specimen. We propose using the so-called …
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On a Proposal for a Continuum With Microstructure
… by identifying the microstructure with dislocations. In particular, the continuum is viewed as a superimposed state made up from a perfect lattice state, an immobile dislocation state, and a mobile dislocation state. It is assumed that each state evolves continuously in space-time and …
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Modeling dislocation density evolution in continuum crystal plasticity
Dislocations are 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 …
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High mobility strained Si/SiGe heterostructure MOSFETs : channel engineering and virtual substrate optimization
… onto silicon substrates. In this thesis, dislocation dynamics in compositionally graded SiGe layers are explored and mobility enhancements in strained Si/SiGe metal-oxide-semiconductor field-effect transistors (MOSFETs) are evaluated. These results demonstrate the dramatic increases in …
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TOPICS IN STOCHASTICS AND STATISTICS: SHOCK CREATION AND DISSOLUTION FOR STABLE AND LINNIK CONSERVATION LAWS AND TARGET STUDENT RECRUITMENT USING PREDICTIVE MODELING
… in application to mathematical finance and dislocation dynamics. Moreover, it has evolved into a vital and important part of the theory of conservation laws. It is known from recent work that the solutions of the fractal conservation laws exhibit shocks for bounded, odd, and convex on …
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Atomistic simulations of deformation in Metallic Nanolayered Composites
… response of Cu/Nb MNCs are examined by Molecular Dynamics (MD) simulations. The study of the strength of MNCs show that small changes in both d and h play a profound role in the relative plastic contributions from grain boundary sliding and dislocation glide. The interplay of d and h leads to a …
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Ductility in high chromium super-ferritic alloys
… The ductility is enhanced by raising the mobile dislocation density, and this may be achieved by pre-straining recrystallised material, or increasing the number of dislocation sources in the otherwise source-poor material. The generation of mobile dislocations by prismatic punching at second …
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Phase field modeling of the defect evolution and failure
… <p>In the first part of the work, a phase field dislocation dynamics (PFDD) approach is introduced, which tracks the evolution of the dislocations in ultrafine and nano grained metals and takes into account the elastic interaction between dislocations, obstacles and the applied resolved shear …
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Stochastic dynamics in spatially extended physical and biological systems
… systems, and (3) the velocity statistics of edge dislocations in plastic deformation of crystalline material. In Part I, I present a new model for the origin of homochirality, the observed single-handedness of biological amino acids and sugars, in prebiotic self-replicator. Homochirality has long …