Abachizadeh - M.Sc. student, Ferdowsi University of Mashhad Mashhad, Iran
Tahani - Assistant professor, Ferdowsi University of Mashhad،Mashhad, Iran
Soheili - M.Sc. student, Ferdowsi University of Mashhad Mashhad, Iran

Ant colony optimization (ACO), a heuristic method which has been successfully applied on problems in the field of applied mathematics and industrial engineering, is described and applied on two mechanical engineering benchmark problems. The first problem, being the optimization of gear ratio in a gear train, consists of discrete variables which are the number of gear teeth. The second benchmark is the shape optimization of a composite leaf spring which deals with continuous geometrical variables of width and thickness. In the problem of designing a gear train, the CO results are identical to the solution obtained by direct enumeration which is deterministically the global optimum. In the next problem, the ACO results are compared with the GA reported in the literature, showing clearly that the ACO has outperformed GA. The results demonstrate that the ACO method which has been first applied on traveling salesperson problem and is discrete in nature, has been effective in optimization of both problems and can be a promising candidate for optimization of problems in the field of structural and mechanical engineering.

ant colony optimization، structural optimization، gear ratio، composite leaf spring