A new semi-analytical method for nonlinear stability analysis of stiffened laminated composite doubly-curved shallow shells

Abstract

Nonlinear stability behavior of rotationally-restrained stiffened laminated composite doubly-curved shallow shells with imperfection subjected to in-plane shear and compression loading is evaluated using a new and unique semi-analytical method. The new equivalent model with variable stiffness for both centrically- and eccentrically-stiffened shells is developed, and Heaviside function is uniquely applied to construct the variable stiffness of stiffened shells along two orthogonal directions. The Galerkin method is implemented to solve the nonlinear governing equation, and the snapping phenomenon of stiffened shell structures is then captured by the arc-length method (Riks method). The nonlinear load-deflection equilibrium paths of centrically- and eccentrically-stiffened plates and four typical shallow shell structures are studied, and both the real geometry and equivalent models by the numerical finite element method are used to validate the present semi-analytical approach. Finally, the influence of amplitude of imperfection, edge rotational restraint spring stiffness, load ratios, curvature radii, and distribution of stiffeners on nonlinear stability behavior of stiffened shells are discussed to demonstrate effective application of present semi-analytical method.