Nonlinear Bifurcation and Post-buckling Analysis of Cylindrical Composite Stiffened Laminates Based on Weak Form Quadrature Element Method

This paper presents a weak form quadrature element formulation in the analysis of nonlinear bifurcation and post-buckling of cylindrical composite stiffened laminates subjected to transverse loads. A total Lagrangian updating scheme is used in combination with arc-length method, and the branch-switching method is adopted to identify the whole post-buckling procedure of the laminates. The formulation of the shell model and beam model are based on the basic concept of Ahmad. The coincidence of discrete nodes and integration points in quadrature element endows it with compactness and conciseness in the nonlinear buckling analysis of the cylindrical stiffened laminates. Several numerical examples are firstly presented to verify the effectiveness and accuracy of present formulation. Parametric studies on the effects of the height-to-breadth ratio, lamination schemes, positions, distribution, number of the stiffeners on the bifurcation and post-buckling behavior are performed.