Nonlinear Vibration Analysis of a Composite Cylindrical Shell on a Viscoelastic Foundation and under Subsonic External Air Flow

In this paper, the nonlinear vibration analysis of a symmetric laminated composite cylindrical shell on a viscoelastic foundation under a subsonic external air flow has been investigated. The boundary conditions for both ends of the cylindrical shell are clamped conditions. The governing equations of motion in the longitudinal, circumferential and radial directions are derived in conducture with the Donnel’s nonlinear shell theory. Using Galerkin method, three nonlinear partial differential equations of motion are transformed to a nonlinear ordinary equation of motion governing lateral (radial) vibration of the shell. Then, the relations for linear and nonlinear natual frequencies and amplitude-dimensionless natural frequency of the shell are calculated. The effects of variations in different values of parameters including orientation angles of lamina in layerwise laminate, stiffness and damping of viscoelastic foundation and the external applied load on the free and forced vibration behavior of the shell are all studied in this paper analyses. Moreover, the time history of radial displacement of midpoint of the shell using linear and nonlinear analyses. Are also presented.