Research Article An Atomistic-Based Continuum Modeling for Evaluation of Effective Elastic Properties of Single-Walled Carbon Nanotubes M. S. M. Al-Kharusi, K. Alzebdeh, and T. Pervez Department of Mechanical and Industrial Engineering, College of Engineering, Sultan Qaboos University, P.O. Box 33, 123 Al-Khod, Oman Correspondence should be addressed to K. Alzebdeh; alzebdeh@squ.edu.om Received 22 September 2015; Revised 31 January 2016; Accepted 18 February 2016 Academic Editor: Ilaria Armentano Copyright © 2016 M. S. M. Al-Kharusi et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Te mechanical behavior of SWCNTs is characterized using an atomistic-based continuum method. At nanoscale, interatomic energy among carbon atoms and the corresponding force constants are defned. Subsequently, we used an atomistic fnite element analysis to calculate the energy stored in the SWCNT model, which forms a basis for calculating efective elastic moduli. In the fnite element model, the force interaction among carbon atoms in a SWCNT is modeled using load-carrying structural beams. At macroscale, the SWCNT is taken as cylindrical continuum solid with transversely isotropic mechanical properties. Equivalence of energies of both models establishes a framework to calculate efective elastic moduli of armchair and zigzag nanotubes. Tis is achieved by solving fve boundary value problems under distinct essential-controlled boundary conditions, which generates a prescribed uniform strain feld in both models. Elastic constants are extracted from the calculated elastic moduli. While results of Young’s modulus obtained in this study generally concur with the published theoretical and numerical predictions, values of Poisson’s ratio are on the high side. 1. Introduction Extensive research work done by researchers from science and engineering background in composite materials opens new prospects for future short and long term technologies, which will reshape the practical application of modern composites. Currently, the research themes on nanocom- posites and/or composites with nanoreinforcements face the challenges of characterization, fabrication, and application. Signifcant amount of experimental and numerical research work is done to characterize the nanoreinforcement. But fur- ther research is needed to bring these to the level of practical application. Tese nanocomposites are becoming favorable candidates for materials with a bright future in a wide variety of industries such as transport, defense, electronics, and biomedicine, to name a few. Hence, it is important that the mechanical properties of these composite constituents, particularly the carbon nanotubes (CNTs), be predicted accu- rately. Further, the potential use of carbon nanotubes (CNTs) as a reinforcing material in nanocomposites and light weight composite structures has triggered a need to explore their mechanical properties and assess their deformation under mechanical loading. Te unique structure and geometric confguration of CNTs along with their high stifness, low density, and large aspect ratio have propelled an increasing demand in furthering the research to quantify their elastic properties as well as to explore possible applications in diferent felds. Various experimental and theoretical approaches have been developed or used to characterize the elastic behavior of SWCNTs. Several investigators [1, 2] have conducted exper- imental studies to investigate the mechanical properties of carbon nanotubes. Tese experiments were mainly based on atomic force microscopy (AFM) and transmission electron microscopy (TEM) and were able to confrm that CNTs possess superior mechanical properties. However, the exper- imental error bars are too large to state exact characteristics of CNTs of diferent confgurations, sizes, and structures. Te wide scatter in the experimentally reported values of the elastic constants of the CNT can be attributed to the lack Hindawi Publishing Corporation Journal of Nanomaterials Volume 2016, Article ID 8641954, 13 pages http://dx.doi.org/10.1155/2016/8641954