OPTIMAL-DESIGN OF TRUSSES USING AVAILABLE SECTIONS

One of the simplest approaches for optimizing statically loaded trusse s is to handle stress constraints using the fully stressed design (FSD ) technique. The displacement constraints are handled using the optima lity criteria (OC) approach. Optimizing structural systems require reg arding design variables as discrete quantities. The easiest approach i s to consider the variables continuous and later approximate them to t he immediate higher available discrete values. This procedure leads to nonoptimal designs. A modified approximation rule is suggested here. This rule leaves some displacement constraints violated, but a new tec hnique based on 1-0 integer programming (IP) is developed to satisfy t he displacement constraints. The proposed technique uses very few desi gn variables. It is very efficient for designing trusses using availab le sections. Problems involving up to 1027 design variables have been solved efficiently with this approach.