Aluminum Alloy Single-layer Spherical Reticulated Shell Stability Performance And Steady Technology Research

Aluminum alloy has the advantages of light weight,high strength,environmental protection and high efficiency,and has occupied a place in the large-span space structure.Therefore,stability becomes a key issue for research.In this paper,through the finite element software ABAQUS,the stability study of the single-layer aluminum alloy reticulated shell using the plate joint is carried out with the idea of "rod to structure".Firstly,numerical simulation is used to study the calculated length coefficient of the rods in the reticulated shell,and the relevant recommended values are obtained.Then,the stability of single-layer aluminum alloy reticulated shell using plate joints is studied,focusing on two factors: joint stiffness and joint failure.Finally,in order to improve the stability of the single-layer aluminum alloy reticulated shell structure,a prestressed cable support system is introduced,and the concept of the aluminum alloy chord-supported dome structure is proposed and the stability is studied.In the study of the in-plane and out-of-plane calculation of length coefficients of single-layer aluminum alloy reticulated shell members,the method adopted is "improved overall method + Euler formula inverse".The research results show that the out-of-plane calculated length coefficient of the single-layer reticulated shell rods of the aluminum alloy plate joints is between 1.6 and 2.0,accounting for more than60% of the total reticulated shell rods,and the value of 1.6 in the current specification cannot provide enough.It is recommended to appropriately enlarge the value to 1.9during design.In the single-layer reticulated shell of the aluminum alloy plate joint,the calculated length coefficient of the member in the plane is mostly between 0.62 and 0.86,so the value of 1.0 in the specification still has sufficient safety reserve.In the analysis of the structural stability of the single-layer aluminum alloy reticulated shell,the python code is used to establish the aluminum alloy single-layer reticulated shell model considering the semi-rigidity of the nodes and the failure of the nodes.Considering the influence of structural geometry,material,defects and other factors,carry out parametric analysis of its stability.The differences between the stability of reticulated shells with different node performance are compared.The study found that the ultimate bearing capacity of semi-rigid reticulated shells decreased by about 10% compared with rigid reticulated shells;considering the failure of nodes,the ultimate bearing capacity of reticulated shells decreased by about 20%compared to ordinary semi-rigid reticulated shells.The influence of joint semi-rigidity and joint failure on the stable bearing capacity of the structure cannot be ignored.In the research of structural stability lifting technology,the prestressed cable support system was introduced into the aluminum alloy single-layer reticulated shell,and the concept of aluminum alloy string support dome was proposed.The stability performance of the chord-supported dome structure is compared with that of the ordinary single-layer reticulated shell.Then,the influence of parameters such as structural geometric dimensions,initial geometric defects,and prestress settings on the stable bearing capacity of the structure is analyzed.The study found that the introduction of the prestressed cable-bracing system can well improve the stability of the aluminum alloy single-layer reticulated shell structure,and the smaller the risespan ratio is,the more obvious the improvement effect is.The improvement of the stable bearing capacity of the aluminum alloy chord dome relative to the aluminum alloy single-layer reticulated shell is more than twice that of the steel chord dome relative to the single-layer steel reticulated shell.The structural stability of aluminum alloy chord-supported dome is sensitive to span,rise-span ratio,initial geometric defects,etc.The increase of strut height and the uniform distribution of live load are all conducive to the improvement of structural stability and bearing capacity.