Two types of optimization of a cylindrical shell subjected to lateral pressure

Two types of optimization of thin-walled cylindrical shells loaded by lateral pressure are analyzed in this paper, with arbitrary axisymmetric boundary conditions and the volume being constant. The first is to find the optimal thickness to minimize the maximum deflection of a cylindrical shell. Here expressions of the objective function are obtained by the stepped reduction method. The optimal designs are reduced to nonlinear programming problems with an equality constraint. In minimizing the maximum deflection, the position of the maximum deflection from a previous iteration is used as the next one. The second is to find the optimal thickness to maximize the buckling pressure of shell. A buckling criterion of a shell is derived on the basis of an energy principle. An optimization criterion is formulated as the maximum of the buckling pressure. Moreover, the space of allowable solutions is defined. This procedure converges quickly and numerical results show the effectiveness of the method. Several examples are provided to illustrate the methods.