Imperfection Sensitivity Analysis of Double Domes Free Form Space Structures

This paper investigates the effects of applying different buckling modes obtained by linearized eigenvalue buckling analysis as the initial imperfection for double domes free form space structures. Nonlinear elastic–plastic analysis of rigidly jointed single layer double domes are carried out using the finite element method. Having verified the finite element modeling, several different collapse analyses have been undertaken in order to examine the stability behavior of these structures. By using the approximate-perturbed method, the results of the analyses show that in free form double domes, the lowest buckling modes could not be considered as the effective modes to change the bifurcation equilibrium path into the limit equilibrium one. Therefore, the generalized conformable imperfection mode method has been suggested in the present study in order to apply geometric imperfections in free form double domes. Also, one step method has been suggested in order to eliminate 60% of buckling modes, which are nonsensitive, before applying the approximate-perturbed method.