Interactive topology design of truss structures

This paper presents a procedure for shape synthesis and optimization of truss structures for any given loading and support conditions. An interactive graphics program is developed for rapid construction and/or modification of the (initial) geometric model according to dimensional constraints and designer input. The program automatically formulates the equilibrium equations with compatibility of joint displacement and selects the optimum cross-sectional areas from stored tables. The optimization criterion is the minimum weight of the truss subject to the specified constraints on stress and joint displacement. The program is developed for the design of large scale structures and can automatically optimize the shape of the initial structure by eliminating members and joints which are not needed for carrying loads or maintaining the stability of the truss. The graphics interface allows the user to add, delete or modify the joint coordinates, support locations and the placement of members. The optimization algorithm quickly evaluates the effect of these changes on improving the design merit. Although the numerical examples given for illustrating the process are for 2D trusses, the procedure is readily applicable to 3D structures