In the present study we have investigated axial buckling characteristics of nanocomposite beams reinforced by single-walled carbon nanotubes (SWCNTs). Various types of beam theories including Euler-Bernoulli beam theory, Timoshenko beam theory and Reddy beam theory were used to analyze the buckling behavior of carbon nanotube-reinforced composite beams. Generalized differential quadrature (GDQ) method was utilized to discretize the governing differential equations along with four commonly used boundary conditions. The material properties of the nanocomposite beams were obtained using molecular dynamic (MD) simulation corresponding to both short-(10,10) SWCNT and long- (10,10) SWCNT composites which were embedded by amorphous polyethylene matrix. Then the results obtained directly from MD simulations were matched with those calculated by the mixture rule to extract appropriate values of carbon nanotube efficiency parameters accounting for the scale-dependent material properties. The selected numerical results were presented to indicate the influences of nanotube volume fractions and end supports on the critical axial buckling loads of nanocomposite beams relevant to long- and short-nanotube composites., {"references":["S. Iijima, 1991, Helical Microtubes of Graphite Carbon, Nature 354, pp.\n56-58.","K. Liao and S. Li, 2001, Interfacial Characteristics of a Carbon\nNanotube-Polystyrene Composite System, Applied Physics Letters 79,\npp. 4225-4227.","C. Wei, K. Cho, and D. Srivastava, 2001, Chemical Bonding of Polymer\non Carbon Nanotube, MRS 2001 Meeting proceeding.","K. Lau, 2003, Interfacial Bonding Characteristics of Nanotube/Polymer\nComposites, Chemical Physics Letters 370, pp. 399-405.","E. Hammel, X. Tang, M. Trampert, T. Schmitt, K. Mauthner, and A.\nEder, 2004, Carbon Nanofibers for Composite Applications, Carbon 42,\npp. 1153-1158.","Y. Han and J. Elliott, 2007, Molecular Dynamics Simulations of the\nElastic Properties of Polymer/Carbon Nanotube Composites,\nComputational Materials Science 39, pp. 315-323.","A. Labuschange, N.F.J. Van Rensburg, and A.J. Van der Merwe, 2009,\nComparison of Linear Beam Theories, Mathematical and Computer\nModelling 49, pp. 20-30.","H.S. Shen, 2009, Nonlinear Bending of Functionally Graded Carbon\nNanotube-Reinforced Composite Plates in Thermal Environments,\nComposite Structures 91, pp. 9-19.","H. Haftchenari, M. Darvizeh, A. Darvizeh, R. Ansari, and C.B. Sharma,\n2007, Dynamic Analysis of Composite Cylindrical Shells using\nDifferential Quadrature Method (DQM), Composite Structures 78(2),\npp. 292-298.\n[10] P. Malekzadeh and A.R. Fiouz, 2007, Large Deformation Analysis of\nOrthotropic Skew Plates with Nonlinear Rotationally Restrained Edges\nusing DQM, Composite Structures 80(2), pp. 196-206.\n[11] M.A. De Rosa, N.M. Auciello, and M. Lippiello, 2008, Dynamic\nStability Analysis and DQM for Beams with Variable Cross-Section,\nMechanics Research Communications 35(3), pp. 187-192.\n[12] Y.J. Hu, Y.Y. Zhu, and C.J. Cheng, 2009, DQM for Dynamic Response\nof Fluid-Saturated Visco-Elastic Porous Media, International Journal of\nSolids and Structures 46(7-8), pp. 1667-1675.\n[13] O. Sepahi, M.R. Forouzan, and P. Malekzadeh, 2010, Large Deflection\nAnalysis of Thermo-Mechanical Loaded Annular FGM Plates on\nNonlinear Elastic Foundation via DQM, Composite Structures 92(10),\npp. 2369-2378.\n[14] S.C. Pradhan and T. Murmu, 2010, Application of Nonlocal Elasticity\nand DQM in the Flapwise Bending Vibration of a Rotating\nNanocantilever, Physica E 42(7), pp. 1944-1949.\n[15] I. Hanasaki, A. Nakatani, and H. Kitagawa, 2004, Molecular Dynamics\nStudy of Ar Flow and He Flow Inside Carbon Nanotube Junction as a\nMolecular Nozzle and Diffuser, Science and Technology of Advanced\nMaterials 5, pp. 107-113.\n[16] K. Bi, Y. Chen, J. Yang, Y. Wang, and M. Chen, 2006, Molecular\nDynamics Simulation of Thermal Conductivity of Single-Wall Carbon\nNanotubes, Physics Letters A 350, pp. 150-153.\n[17] Nanorex Inc., 2005, NanoHive-1 v.1.2.0-b1, www.nanoengineer-1.com\n[18] S.J. Stuart, A.B. Tutein, and J.A. Harrison, 2000, A Reactive Potential\nfor Hydrocarbons with Intermolecular Interactions, Journal of Chemical\nPhysics 112, pp. 6472-6486\n[19] C.F. Cornwell and L.T. Wille, 1997, Elastic Properties of Single-Walled\nCarbon Nanotubes in Comparison, Solid State Communications 101, pp.\n555-558.\n[20] V.N. Popov, V.E. Van Doren, and M. Balkanski, 2000, Elastic\nProperties of Crystals of Single-Walled Carbon Nanotube, Solid State\nCommunications 114, pp. 395-399."]}