Nonlinear structural-acoustic analysis of orthogonally stiffened composite cylindrical shells with piecewise isolators

This paper is concerned with the numerical analysis of the structural and acoustic responses of a stiffened composite cylindrical shell attached with piecewise isolators. The system is immersed in an infinite acoustic fluid. The cylindrical shell is reinforced by a series of circumferential rings and longitudinal stringers. The isolators in the cylindrical shell contain motion-limiting stops, the restoring forces of which are expressed as bi-linear functions of the isolator deformation. A modified variational method is adopted to establish the nonlinear dynamics model of the structural system, and the acoustic fluid is modelled by a time-domain boundary element method. The contribution of the grouped circumferential wave modes of the shell to the nonlinear vibration and radiated sound responses of the coupled structural system is examined.