Nonlinear vibrations of double-wall cylindrical shells

Many flight and high-speed ground transportation vehicles are constructed from thin wall shells. Power plants and aerodynamic flow could impose severe mechanical, aerodynamic and thermal loads to the shells and cause nonlinear vibrations and unacceptable transmitted noise levels. We present an analytical model to predict the nonlinear response of a double wall cylindrical sandwich shell subjected to random excitation. Nonlinear spring-dashpot models are integrated into the system to characterize the behavior of the soft core, separating the inner and outer shells. Donnell's thin shell theory is used to develop the governing nonlinear equations of motion. A Monte Carlo simulation of stationary random processes, multi-mode Galerkin-like approach, and numerical integration procedures are used to develop linear and nonlinear response solutions of simply-support cylindrical shells. Numerical results include time domain response histories, root mean square values and response spectral densities. Parametric studies are performed to investigate the effects of nonlinearity, shell thickness, core stiffness and core thickness.