A numerical study on nonlinear bending performance of transversely loaded composite singly curved stiffened surfaces

Abstract

The review of recent literature shows that the bending performances of transversely loaded laminated composite singly curved stiffened surfaces are not studied in detail using the geometrically nonlinear strains. The present paper aims to fill that void and proposes an isoparametric C° finite element formulation combining von-Karman nonlinearity and Sanders’ first approximation theory. The curved surfaces are simulated using nonlinear strains. The stiffeners are formulated using geometrically linear and nonlinear strains. The correctness of the proposed approach is confirmed through solution of benchmark problems. The relative performances of stiffened curved surfaces in terms of maximum transverse displacements are studied for industrially important parametric variations like boundary conditions, laminations, stacking sequences, and number, orientations, eccentricities, and depth of stiffeners. The results are critically discussed and it is concluded that the clamped 0°/90°/0° shell with curved stiffeners (y-stiffener) located below the mid-surface shows the greatest bending stiffness. The nonlinear approach is essential for both shell and stiffener for correct prediction of the transverse displacements. The relatively simpler linear approach can be considered for single x-stiffener only.