Effect of initial nondesign domain on optimal topologies of structures during natural frequency optimization

Abstract

Using the extended evolutionary structural optimization method, an investigation into the effect of an initial nondesign domain on the optimal topology of a two-dimensional structure during the structural natural frequency optimization has been carried out under plane stress conditions. From the related results, it is concluded that (1) the optimal topology of a target structure produced by the problem domain of a small initial nondesign domain is obviously different from that produced by the same problem domain of a large initial nondesign domain, although the material used for the target structure is exactly the same in both cases; (2) in most cases, for the same amount of material, the material efficiency of a target structure in relation to the small nondesign domain is higher than that in relation to the large initial nondesign domain; (3) the size of the initial nondesign domain affects the minimum weight of a target structure during the structural natural frequency optimization. Thus, it is suggested that the initial nondesign domain be selected carefully to support the nonstructural lumped masses during the structural natural frequency optimization.