Abstract
The optimum design techniques for mechanical structures are composed of the methods changing a boundary shape of structure and the material properties such as the specific gravity and the Young's modulus. In this paper, the survey for these methods is presented by using the simple truss design models. From the result two important problems are pointed out. One is on the design techniques to determine an optimum layout of mechanical structure and other on the formulation techniques of material design problem. On these problems some ideas from the author's papers presented previously are proposed and discussed.
