Size-dependent torsional buckling analysis of functionally graded cylindrical shell

The size-dependent torsional buckling behavior of functionally graded (FG) cylindrical shell is investigated on the basis of modified couple stress theory using the shell model. The material properties of FG nanoshell are considered change through thickness direction according to power law distribution. The modified couple stress shell theory with the von Karman geometrical nonlinearity is utilized to establish theoretical formulations. The governing equations and boundary conditions are derived using the minimum potential energy principle. As a special case, the torsional buckling of simply supported and clamped FG cylindrical shell is examined using the GDQ method. Afterwards, the influences of geometrical parameters, such as length scale parameter, length, and thickness, as well as material property gradient index of the FG cylindrical shell on the critical torsional buckling moment are studied.