EFFECT OF INITIAL NONDESIGN DOMAIN ON OPTIMAL TOPOLOGIES OF STRUCTURES DURING NATURAL FREQUENCY OPTIMIZATION

Using the extended evolutionary structural optimization method, an inv estigation into the effect of an initial nondesign domain on the optim al topology of a two-dimensional structure during the structural natur al frequency optimization has been carried out under plane stress cond itions. From the related results, it is concluded that (1) the optimal topology of a target structure produced by the problem domain of a sm all initial nondesign domain is obviously different from that produced by the same problem domain of a large initial nondesign domain, altho ugh 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 ma terial efficiency of a target structure in relation to the small nonde sign domain is higher than that in relation to the large initial nonde sign domain; (3) the size of the initial nondesign domain affects the minimum weight of a target structure during the structural natural fre quency optimization. Thus, it is suggested that the initial nondesign domain be selected carefully to support the nonstructural lumped masse s during the structural natural frequency optimization. Copyright (C) 1996 Elsevier Science Ltd.