Design Optimization of Mechanical Elements and Structures: a Review with Application

1,2 Abstract: Numerous applications of optimization techniques to solving real life engineering problems that are highly constrained with multiple objectives have been addressed in the literature. Important stage has now been reached at which an investigation of such developments and their practical possibilities should be made and presented. This paper presents the most outstanding progress and development achieved in the field of optimal design of mechanical and structural elements. A brief historical review of this technology, its current status and future needs are addressed in order to achieve an adequate picture of the subject. The authors present some of the important contributions made by the leading scientists of both the theoretical and practical aspects of the optimization of mechanical structures. The aim now is to assimilate this technology into the practicing design environment. As an application, the optimum design problem of a helical compression spring has been formulated and presented, where the selected design variables included the coil mean diameter, solid wire diameter and number of turns. The developed optimization model considered the minimal mass and the maximum safety designs to be simultaneously achieved. Design constraints encompassed surging, buckling, critical stresses and side constraints as well. Two optimum solutions were given; one was solely based on the minimal mass design while the other combined both of the minimal mass and maximum safety in a linear composite function. Final numerical results for a spring manufactured from oil-tempered carbon steel were obtained by implementing a mixed- integer programming code.