CONVEX AND PROBABILISTIC MODELS OF UNCERTAINTIES IN INITIAL GEOMETRIC IMPERFECTIONS OF LATTICED SHELLS

An efficient approach that employs a convex model to deal with the most unfavorable initial geometrical imperfection of spherical latticed shells is proposed. Initial geometric imperfection, as one of random variables, is a linear combination of Neigenmodes based on linear buckling analysis. The deviation of Ndominant mode shapes is assumed to vary on an ellipsoidal set in the N-dimensional Euclidean space. The limit load of nonlinear buckling will be determined as a function of the Nlinear buckling mode amplitudes. This approach can replace the computationally expensive probabilistic approach, typically used in the study of imperfection sensitive structures. A Monte Carlo simulation has been performed to validate the results obtained by the convex model. ANSYS Parametric Design Language secondary development is used to carry out the finite element analysis.