The present paper demonstrates and discusses elastic bucking characteristics of single layer latticed shells composed of hexagonal grids. A conventional method to calculate linear buckling loads, based on continuum analogy, is found to be also effective like other grid patterns. The bucking mode yields long overall buckling waves and is found to be non-extensional.
The range of knockdown factors, the ratios of an elastic buckling load where the analysis considers geometric nonlinear effect to the linear buckling, is also investigated by nonlinear FE analysis. The lowest value is reduced to slightly above 0.5 even without geometric imperfection. The knockdown factor and its reduction due to geometric imperfection are mainly affected by the geometry and slenderness. After all, the range of knockdown factors is found to be above 0.5, based on the elastic nonlinear FE analyses in which the maximum imperfection amplitude is set to 1/500 of the span. The knockdown factors are also compared with the calculations by the reduced stiffness buckling theory.
