Truss shape optimization with multiple displacement constraints

This paper presents an evolutionary node shift method for truss shape optimization of weight minimization problems. The structure is subject to multiple displacement constraints under multiple load cases. Nodal coordinates are the design variables. Based on the sensitivity analysis, the optimum shape is achieved gradually from the initially underdesigned configuration by shifting the most efficient nodes with minimum weight increase. Moving directions and intervals of node shifts are determined automatically. The optimum solution is checked by the Kuhn-Tucker optimality conditions. Limitations of truss shape optimization are studied. The feasibility and effectiveness of the method are investigated with four typical truss structures.