A novel stability analysis method of single-layer ribbed reticulated shells with roof plates

Abstract

The steel dome of liquefied natural gas (LNG) storage tanks comprises a curved roof plate welded onto a single-layer ribbed reticulated shell (SLRR shell). However, the roof plate may cause diaphragm effects, which may resulting in instability of the steel dome at a relatively low load level. In this paper, an innovative equivalent single-layer ribbed reticulated shell (ESLRR shell) was proposed to investigate the impact of the diaphragm effect. Specifically, the roof plate and H-shaped radial beam were equated as radial irregular beams based on the principle of plate-shell composite action. Next, we performed a systematic analysis of the instability mechanisms in the ESLRR shell, revealing the interaction between the beam buckling and the overall structural instability. Finally, through parametric study, we explored the effects of roof plate thickness and rise-to-span ratio on the ESLRR shell, and obtained the optimal structural parameters. The results show that the proposed method effectively solves the challenges associated with the presence of roof plates in LNG storage tanks steel dome stability analysis; Under the combination of weak boundary stiffness and high bending moment, radial irregular beams are more prone to buckling; Increasing roof plate thickness or rise-to-span ratio can reinforce the stability of the ESLRR shell. Overall, this research work provides theoretical guidance for the future design and optimization of LNG storage tank domes.