Finite element delamination model for vibrating composite spherical shell panels with central cutouts

The finite element model of vibrating laminated spherical shell panels with delamination around a central cutout is developed based on the third-order shear deformation theory of Sanders. In the finite element formulation for the delamination around cutout, the seven degrees of freedom per each node are used with transformations in order to fit the displacement continuity conditions at the delamination region. The numerical results obtained for plates and shells with delaminations are in good agreement with those of other preceding investigations. The new results for shell structures in this study mainly show the effect of the interactions between the radius–length ratio and other various parameters, for example, delamination size, the number of layer and location of delamination in the layer direction. Key observation points are discussed and a brief design guideline is given.