Copyright © 2010 Tech Science Press CMC, vol.18, no.2, pp.155-182, 2010 Buckling and Postbuckling Behavior of Functionally Graded Nanotube-Reinforced Composite Plates in Thermal Environments Hui-Shen Shen 1, 2 and Zheng Hong Zhu 3 Abstract: This paper investigates the buckling and postbuckling of simply sup- ported, nanocomposite plates with functionally graded nanotube reinforcements subjected to uniaxial compression in thermal environments. The nanocomposite plates are assumed to be functionally graded in the thickness direction using single- walled carbon nanotubes (SWCNTs) serving as reinforcements and the plates’ ef- fective material properties are estimated through a micromechanical model. The higher order shear deformation plate theory with a von Kármán-type of kinematic nonlinearity is used to model the composite plates and a two-step perturbation tech- nique is performed to determine the buckling loads and postbuckling equilibrium paths. Numerical results for perfect and imperfect, geometrically mid-plane sym- metric functionally graded carbon nanotube reinforced composite (FG-CNTRC) plates are obtained under different sets of thermal environmental conditions. The results for uniformly distributed CNTRC plate, which is a special case in the present study, are compared with those of the FG-CNTRC plate. The results show that the buckling loads as well as postbuckling strength of the plate can be significantly increased as a result of a functionally graded nanotube reinforcement. The results reveal that the carbon nanotube volume fraction has a significant effect on the buck- ling load and postbuckling behavior of CNTRC plates. Keywords: Nanocomposites; Functionally graded materials; Plates; Buckling; Postbuckling 1 School of Ocean and Civil Engineering & State Key Laboratory of Ocean Engineering, Shanghai Jiao Tong University, Shanghai 200030, People’s Republic of China 2 Corresponding author. E-mail address: hsshen@mail.sjtu.edu.cn 3 Department of Earth and Space Science and Engineering, York University, 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3