Dissertation Defenses

Doctoral Dissertation Announcement

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Candidate: Yang Yang

Degree of: Doctor of Philosophy

Department: Mechanical and Aeronautical Engineering

Title: Atomic-based Finite Element Simulation of Carbon Nanotubes

Committee:
Dr. William Liou, Chair
Dr. Christopher Cho
Dr. Tianshu Liu
Dr. Yirong Mo

Date: Monday, August 25, 2008 10:00 a.m. - 12:00 p.m.
Parkview Campus, D206 Engineering Building

Abstract:
Since first found in the form of multi-walled carbon nanotubes (MWNTs) by Iijima (1991), carbon nanotubes (CNT) have gained overwhelming attentions for their outstanding and unique properties from across the spectrum of the science and engineering fields. CNTs are structurally perfect: small size, low density, high stiffness, and high strength (Qian et al., 2002); and their electronic properties depend on the particular distortion as well as the initial tube diameter and chirality, ranging from narrow-gap or moderate-gap semiconducting to metallic (Pantano et al., 2004b), which can be utilized in nanoscale sensors and devices. These appealing characteristics provide strong drives for the possible applications of CNTs as a novel material. However, a sufficient understanding of the mechanics of CNTs and the effects of mechanical deformations on the electrical properties still remains obscure. This study focuses on CNTs’ mechanical responses to externally applied loads by implementing a new atomistic formulation-based finite element method proposed by Arroyo and Belytschko (2002). The skeleton of this new diagram lies in two facts. Firstly, it uses the subdivision scheme which can render a high-order smooth limit surface so that Kirchoff-Love thin shell formulae could be applied; secondly the Born rule for space-filling crystals is used to link the atomistic and the continuum deformations.