OPTIMIZATION OF STRUCTURE AND MATERIAL PROPERTIES FOR SOLIDS COMPOSEDOF SOFTENING MATERIAL

Recent results on the design of material properties in the context of global structural optimization provide, in analytical form, a predicti on of the optimal material tensor distributions for two or three dimen sional continuum structures. The model developed for that purpose is e xtended here to cover the design of a structure and associated materia l properties for a system composed of a generic form of nonlinear soft ening material. As was established in the earlier study on design with linear materials, the formulation for combined ''material and structu re'' design with softening materials can be expressed as a convex prob lem. However, in contrast to the case with linear material, the optima l distribution of material properties predicted in the nonlinear probl em depends on the magnitude of load. Computational solutions are prese nted for several example problems, showing how the optimal designs var y with different values assigned to data that fix the load and materia l parameters.