Estimation of Strength and Stiffness of Carbon Nanotubes

• Main Authors: Yan-JiaHou, 侯彥嘉
• Other Authors: Chyanbin Hwu
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/37562405479015271463

碩士 === 國立成功大學 === 航空太空工程學系 === 102 === ABSTRACT Subject: Estimation of Strength and Stiffness of Carbon Nanotubes Graduate: Yan-Jia Hou Advisors: Chyanbin Hwu Since its discovery, the superior properties of carbon nanotubes (CNTs),such as high strength, toughness and light weight, makes it become a popular reinforcing material. Our purpose is to estimate its nonlinear mechanical properties by combining Finite Element Method and Molecular Dynamics. According to many researches, the covalent bonds between two nearest-neighboring atoms are simulated as beam elements. The beam properties of the finite element model are obtained from in the modified Morse interatomic potential, and the Young's modulus, Poisson's ratio, Yield strength and Ultimate strength can then be estimated from the plotted stress-strain relation. Although most of the predicted results are in good agreement with the existing data, there is a slight difference in ultimate strength. The difference can be accepted since our simulation is applied to defect-free (without Stone-Wales defect). The effects of tube type, axial length and element size on the mechanical properties are also discussed. On our investigations, the Young’s modulus ranges from 1 to 1.2 TPa, the Poisson’s ratio from 0.17 to 0.25 and the yield strength from 20 to 30 GPa.