A computational method is presented for the optimum design of structures subject to external forces from uncertain directions. Finite element method is used for structural analysis so as to make use of the algorithm for optimizing various types of structures.
As the loading direction changes, the member forces will also vary accordingly. The direction most unfavorable to each member does not necessarily coincide each other. Hence in each member the critical member force and its corresponding direction need to be found before each optimization step. Constraints on stresses, bucklings, dispacements and member sizes are considered. Also presented is the case in which multiple external forces vary their directions independently. Example problems are solved to show the validity of the optimization algorithm.
The concept presented here is useful for the optimum design of towers and marine structures.