Geometric nonlinear analysis of stiffened prismatic shell structures using the compound strip method

This paper shows that geometric nonlinear behaviour of stiffened prismatic shells can be successfully modelled with the compound strip method. Longitudinal and transverse beams are introduced into the finite strip method using strain energy through their interface lines. Advantages of the presented method are the low number of employed degrees of freedom and the semi-analytical approximation of the displacement field. This method also addresses one of the main drawbacks of the finite strip method, which is the inclusion of intermediate supports. All matrices are derived in a closed form and analytical solutions of five characteristic integrals are given. Numerical analysis shows that the compound strip method gives reasonably accurate results for complex equilibrium paths when compared with the finite element method. This method gives stiffer solutions for softening branch and more flexible results for hardening branch of the equilibrium path. Convergence of all variables is very fast except the longitudinal stresses in the shell above the transverse beam. Simple parallelization is applied and the computation time is significantly reduced.