A computational study in optimum formulations of optimization problems on laminated cylindrical shells for buckling I. Shells under axial compression

The paper deals with different formulations of optimization problems on bucking of multi-layered composite cylindrical shells under axial compression. The problem is posed on searching the global extremum and local extrema of the buckling load such that are maximum close to the global extremum (or practically the same) and more convenient for the design and production of real shells. A comparison is done for uni-, two- and multi-dimensional formulations of optimization problems for the shells including different number of the layers. It is shown that, for most practical cases, there is no gain in increasing the number of the layers above four and the number of variable parameters above two. Recommendations are given on the selection of rational structures for two- and three-layered shells. Known rules are studied for different intervals of shell dimensions and material characteristics.