Stability Performance and Theoretical Design Method for Single-Layer Composite Reticulated Shells with Aluminum Alloy Honeycomb Plates

A single-layer aluminum honeycomb plate–rod composite reticulated shell is a relatively flexible spatial structure and is therefore sensitive to overall instability. To develop a stability bearing capacity design method for single-layer composite reticulated shells with aluminum alloy honeycomb plates, a stability bearing capacity test is conducted to investigate the failure modes and load-carrying behavior. A finite element model is established based on equivalent modeling of the honeycomb plates and the composite action between the plates and rods, and its accuracy is validated against the test results. Extensive parametric analyses are subsequently performed to quantify the effects of initial geometric imperfections, support conditions, joint stiffness, rise-to-span ratio, number of circumferential rings, rod cross-sectional dimensions, and honeycomb plate thickness. Based on theoretical derivation and regression analysis, a design formula for single-layer composite reticulated shells with aluminum alloy honeycomb plate is proposed. The results demonstrate that global instability of plate–rod composite reticulated shells is governed primarily by localized plastic bending of aluminum alloy rods near the apex and middle rings, with the proposed equivalent model accurately capturing the structural response and ultimate load within a 4.4% error. Joint stiffness, rod cross-sectional dimensions, number of circumferential rings, rise-to-span ratio, and honeycomb plate thickness substantially enhance stability, whereas initial geometric imperfections markedly reduce structural stiffness, with their destabilizing effect becoming less pronounced beyond S/300. The proposed design formula achieves accurate and conservative predictions of the overall stability capacity, providing a practical basis for the stability design of this novel spatial structural system.