| In this Dissertation, the fundamentals of mechanics of nanomaterials in micro/nano-scale applications are established and discussed. Because nanomaterials are distinguished with unique material structures and characteristics, nanomaterials reflect unique mechanics in various applications. The mechanics of nanomaterials differs from the conventional mechanics of materials in the need to incorporate special measures that can capture the material's mechanics as a function of the material structure and the material size. Therefore, new experimental and theoretical models should be developed to give the crucial understanding of the physics of the mechanics of nanomaterials.;In this Dissertation, we harness the fundamental laws of continuum mechanics, materials science, solid state physics, and lattice dynamics to understand and model the mechanics of nanomaterials in small-scale applications. In the first part of this Dissertation, the essential aspects that should be considered when developing models for the mechanics of nanomaterials are determined and discussed. In addition, the models and theories that have the merits of representing the mechanics of nanomaterials are derived and developed. To guarantee accurate modeling of the mechanics of nanomaterials, these models and theories incorporate measures that capture the material structure and size effects. In the second part, models are proposed for nanomaterials characterization. Micromechanical models are developed for nanostructured materials. In the context of these models, the effective elastic properties of nanostructured materials are related to the size of the nanoinhomogeneities forming their material structures. These models are then harnessed to report the elastic properties of nanocrystalline materials including diamond, silicon, copper, aluminum, silver, gold, and platinum when decreasing the grain average size from 200 nm to 2 nm, for the first time. The experimental observations for the degradations in the elastic properties of nanocrystalline materials are captured by the developed micromechanics models. Moreover, continuum models for the materials dispersions are developed for single crystalline nanomaterials. These models are used to report the elastic properties of diamond, graphite, silicon, copper, silver, gold, platinum, barium oxide, lithium deuteride, lithium hydride, magnesium lead, magnesium stannide, and nickel oxide single nanocrystals. In the third part, the developed fundamentals, theories, and models are harnessed to represent the mechanics of nanomaterials in selected potential micro-/nano-scale applications. First, the sensitives and resolutions of carbon nanotubes-based mechanical resonators are reported for mass sensing applications. Second, the nonlinear dynamics of electrostatically actuated micro/nano-resonators made of functionally graded materials and nanocrystalline materials are modeled and investigated. Third, the elastic and the buckling characteristics of nanobeams and nanowires are reported. This dissertation creates a benchmark for future studies on nanomaterials and their mechanics. |
