Torsional Stability of Cylindrical Shells with Functionally Graded Middle Layer on the Winkler Elastic Foundation

In this study, the torsional stability analysis is presented for thin cylindrical with the functionally graded (fg) middle layer resting on the winker elastic foundation. the mechanical properties of functionally graded material (fgm) are assumed to be graded in the thickness direction according to a simple power law and exponential distributions in terms of volume fractions of the constituents. the fundamental relations and basic equations of three-layered cylindrical shells with a fg middle layer resting on the winker elastic foundation under torsional load are derived. governing equations are solved by using the galerkin method. the numerical results reveal that variations of the shell thickness-to-fg layer thickness ratio, radius-to-shell thickness ratio, lengths-to-radius ratio, foundation stiffness and compositional profiles have significant effects on the critical torsional load of three-layered cylindrical shells with a fg middle layer. the results are verified by comparing the obtained values with those in the existing literature.