Theoretical modeling of electromechanical coupling behavior of ferroelectrics and their composites
Item
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Title
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Theoretical modeling of electromechanical coupling behavior of ferroelectrics and their composites
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Identifier
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d_2009_2013:7124d4b7bb23:10152
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identifier
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10418
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Creator
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Cao, Yang,
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Contributor
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Jackie Li
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Date
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2009
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Language
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English
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Publisher
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City University of New York.
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Subject
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Mechanical engineering | Composites | Electromechanical | Ferroelectrics | Modeling | Nanowires | Piezoelectrics
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Abstract
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The aim of this dissertation is to develop suitable theoretical models to study the physical properties of ferroelectrics in terms of temperature and size, and the nonlinear electromechanical coupling behavior of ferroelectrics and their composites under the different loading conditions. Three different models are introduced following applicable scale ranges. First, Texture and Anisotropy theory is used to model nonlinear behaviors of piezoelectric poly-crystals (Taylor-Bishop-Hill like model) without considering interaction between grains or domains. It is suitable in macro-scale range and can be used on both polycrystals and single crystals. Second, a micromechanics approach based on irreversible thermodynamic principle and morphology of spontaneous polarization and domain switch has been extended to study the temperature effects on BaTiO3 single crystals and further for electromechanical coupling behavior of ferroelectric composites by considering the microstructure of the system. The micromechanics approach reaches its limitation when the material size reduces to nano-scale. Finally, Ginzburg--Landau theory has been chosen to determine BaTiO 3 nanowire behaviors under external loading. This powerful phenomenological method was originally developed for macro scale. Here we extend the model to be applicable at nano-scale range and study the polarization field and transition temperature in terms of the size of ferroelectric nanowires. The advantages and disadvantages of each model are discussed. All three models are also compared and verified by existing experiments.
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Type
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dissertation
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Source
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2009_2013.csv
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degree
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Ph.D.
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Program
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Engineering
