Geometrically nonlinear dynamic analysis of variable stiffness composite laminated and sandwich shell panels

The nonlinear free and forced vibration analyses of variable stiffness composite laminated (VSCL) and sandwich shell panels having curvilinear fibres, not yet reported in literature, are conducted based on a higher-order theory. The present structural model considers a third-order shear deformation theory incorporating Murakami zig-zag effects. The analyses are performed using C-0 nine-noded isoparametric element with thirteen degrees of freedom and geometrical nonlinearity is included through von Karman nonlinear strain-displacement relations. The free and forced vibrational responses of the VSCL are established using the eigenvalue solutions and Newmark's time integration technique, respectively. The results obtained using the present finite element formulation are compared with the available three-dimensional exact and two-dimensional analytical and numerical solutions for establishing the validity of the model. The fundamental frequencies and nonlinear transient deflections of VSCL and sandwich spherical and cylindrical shell panels are evaluated considering the effects of curvilinear fibre path, curvature ratio, number of layers and lamination configuration.

Automated summary

In this study, the nonlinear free and forced vibration analyses of variable stiffness composite laminated (VSCL) and sandwich shell panels with curvilinear fibers were conducted using a higher-order theory. The structural model considered a third-order shear deformation theory, and geometric nonlinearity was included through von Karman nonlinear strain-displacement relations. The results were compared with existing exact and analytical solutions to validate the model.