Nonlinear thermal buckling and postbuckling analyses of imperfect variable thickness temperature-dependent bidirectional functionally graded cylindrical shells

• Nonlinear thermal postbuckling of imperfect FGM cylindrical shells is investigated.
• Material properties of the shell may vary in both radial and axial directions.
• Geometric imperfections and thickness variability are also taken into account.
• Material properties are considered to be temperature-dependent.
• The nonlinear governing equations are solved by an updating finite element scheme.

Influences of the thickness variability and bidirectional material heterogeneity on the thermal buckling of the cylindrical shells have not been investigated so far. In the present paper, nonlinear thermal buckling and postbuckling analyses of imperfect, variable thickness cylindrical shells made of bidirectional functionally graded materials undergoing uniform temperature rises are accomplished for the first time, employing a third-order shear-deformation theory, von Karman-type kinematic nonlinearity, and a nonlinear finite element method. Material properties may vary in both radial and axial directions and can be temperature-dependent. Buckling temperature is detected by a modified Budiansky's criterion. The results reveal that temperature-dependency of the material properties reduces the buckling temperature. Moreover, effects of the volume fraction index on decreasing the buckling temperature are more remarkable for higher radius to thickness ratios. Furthermore, effects of reduction of the thickness in the axial direction may be compensated by an appropriate distribution of the material properties.