In this paper, a two-stage PSO based optimization scheme for
truss-structure is developed. The topology of the structure is optimized
from a given ground structure employing a modified BPSO
while the size (and shape) of the member is optimized utilizing
the ARPSO. Niche strategy is implemented to find multiple solutions
since there may exist numerous topologies in truss-structure
design problems. A two-tier, 39-member, 12-node ground structure
is utilized to express the effectiveness of the proposed algorithm
compared with the results derived utilizing one-stage
genetic algorithms and two-stage ant algorithms. The proposed
PSO algorithm was observed to find truss structures superior to
those reported in the literatures with much less calculation time,
lighter weight and more diversity.