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Thermal buckling analyses of S-FGM are investigated by using first order shear deformation theory. Material properties are varied continuously in the thickness direction according to a sigmoid distribution. The thermal buckling behaviours under uniform, linear and sinusoidal temperature rise across the thickness are analyzed. In addition, the effects of temperature field, volume fraction distributions, and system geometric parameters are investigated. The results are compared with the results of the classic plate theory (CPT).

In this paper, an elastic, rectangular, and simply supported, sigmoid functionally graded material (S-FGM) beam of thick thickness subjected to uniformly distributed transverse loading has been investigated. The S-FGM system consists of ceramic (Al2O3) and metal (Al) phases varying through the thickness of beam. Major classes of representative theories such as classical laminate beam theory (CLBT), first-order shear deformation theory (FSDT) and high-order theories (HOTs) have been considered and a unified kinematic formulation is then proposed. The Poisson’s ratio of the thick S-FGM beam is assumed to be constant, but their Young’s moduli vary continuously throughout the thickness direction according to the volume fraction of constituents defined by sigmoid function. The numerical illustrations concern bending response of S-FGM rectangular beams. Qualitative and quantitative assessments of displacement and stress fields have been presented and discussed.

The present paper examines the thermal effect on axially compressed buckling of a multiwalled carbon nanotube based on the gradient elasticity theories. The small-size effect, which plays an essential role in the buckling behavior with large aspect ratios under axial compression coupling with temperature change, is captured by applying different gradient elasticity theories including stress and strain. In this model, each of the nested concentric tubes is regarded as an individual column and the deflection of all the columns is coupled together through the van der Waals interactions between adjacent tubes.