Geometrically nonlinear bending of stiffened composite skewed cylindrical shells under transverse pressure

Abstract

The literature review on relative performances of laminated composite skewed shells confirms that research reports on bending performances of moderately thin, stiffened, laminated composite skewed cylindrical panels, using the geometrically nonlinear approach, are not available. This paper aims to fill that deficiency and proposes a finite element code combining eight-noded, doubly curved elements with modified Sanders’ first approximation theory for thin shells and von Kármán-type nonlinear strains. Correctness of the proposed geometrically nonlinear bending formulation for skewed shells are verified through solutions of benchmark problems. The deflections, force, and moment resultants are reported for different skew angles, laminations, stacking sequences, radius of curvature, plan dimension ratios, and stiffener properties like orientations, numbers, and eccentric positions. The results are discussed critically which reveals that shells having curved edges free and straight edges clamped fabricated using 0°/90°/0° laminate offer the best performances. The biaxial stiffeners, nx = 7, ny = 7, show the minimum deflections and stress resultants. The skewed shells offer greater deflections and hence, must be avoided in industrial practices.