Nonlinear analysis of optimized structure with constraints on systemstability

An optimization algorithm based on an optimality criterion was used to design a minimum weight space truss with different constraint requirements on system stability. The constraints were specified so that the eigenvalues associated with all the critical buckling modes are either equal or separated by a specified factor. For the second case the critical buckling mode was preselected from all the possible critical modes. The designs obtained for the various constraint conditions were analyzed with and without specified geometric imperfections using a nonlinear finite element program which accounts for geometric nonlinearity. The results obtained for various designs were compared for their imperfection sensitivity.