Heuristic Methods in Discrete Structural Optimization

Abstract

This Chapter describes some of the heuristic methods which have been developed for the optimum design of engineering structures using only components which are available in discrete sizes. As a vehicle for describing the methods the optimum design of trusses using rolled steel sections is used. The combinatorial nature of the problem is first briefly described and the necessity for heuristic methods for finding non-rigorous but very close discrete optimum designs are discussed. An investigation of the practical needs of structural designers rather than the capabilities of numerical algorithms demonstrates that the nature of the discrete design problem in practice is very different from that perceived by many researchers. The standardization problem, which is closely related to discrete optimum design, is described and discussed. The Chapter also examines heuristic methods such as the rounding of continuous optimum designs to a discrete solution and describes the linear segmental approach to discrete optimum design.