Minimum Weight Design of Cylindrical Shell with Multiple Stiffener Sizes Under Buckling Constraint

摘要

The buckling equations for the orthogonally stiffened cylindrical shells under uniform axial compression and external pressure and with classical simply supported boundary conditions are formulated by treating the stiffeners as discrete elements. By assuming identical and equally spaced stringers and identical and equally spaced rings, the buckling equations can be uncoupled into several sets of simpler and manageable equations for the symmetric and antisymmetric longitudinal modes and symmetric and antisymmetric circumferential modes. The uncoupled submatrices are further reduced by partitioning and substitution. Effort is made to preserve the sparseness of the matrices in order to use a special compact storage scheme. A method to compute the minimum eigenvalue for a large general eigenvalue problem, the Ritz iteration method combined with Chebyshev procedure, is developed and its accuracies are evaluated. Examples are performed and results are compared to other computational and experimental results available.