Free Vibration Analysis of Pre-Twisted Composite Sandwich Conical Shells Containing Debonding

This article addresses the theoretical investigation of the free vibration behaviours of debonded sandwich conical shells employing finite element method (FEM). The finite element formulation is developed with the aid of the first-order shear deformation theory for both composite facings and core of the sandwich shell. The governing equation of dynamic equilibrium of the debonded sandwich conical shells is deduced by employing Lagrangian equation in which damping is ignored. Necessary compatibility and equlibrium conditions for deformations, forces and moments at the tip of the debonded region are assumed to be satisfied. The results obtained from the formulation are analyzed to depict the effects of stacking sequence and span-wise relative position of the debonding on the free vibration response of the pre-twisted sandwich panels.