Sensitivity of post-buckling behaviour of single layer reticulated shells to loading and member imperfections

The research in postbuckling of reticulated shells has progressed from solution strategies and formulations to focus on structural optimisation, sensitivity etc. Recent studies have highlighted the sensitivity of stability of these structures to topological and member imperfections. In line with such focus, the objective of this paper is study the influence of imperfections in cross-sectional property and loading positions on the limit point and post buckling behaviour of reticulated domes. The paper aims to assess these two parameters according to the sensitivity of the structures to changes in these parameters. A deterministic sensitivity analysis is conducted for variations of these parameters. The geometric non-linear analysis to determine stability limits employs a corotated - Updated Lagrangian (CR-UL) formulation. Here three span-to-rise ratios, and 3 different numbers of rings and crown members each are varied. The effect of each parameter is shown distinguished and they are qualified based on the limit point and deflection (at limit point) sensitivities. The results showed that loading imperfections cause more prominent changes in response to as much as 12% reduction in limit loads, while changes caused by properties of a single member are insignificant. Deflections at corresponding limit load can vary upto 2-3 times. Span-to-rise ratio was found to control the sensitivity to these imperfections more than the number of rings and members at crown.

Learning Objectives:
Explain the effect of loading and member imperfections on stability of single-layer reticulated domes.

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