| Aluminum alloy is used more and more in large-span space structures due to their corrosion resistance,light weight and easy processing.In the aluminum alloy space structure,the node form is mainly a plate node.However,the bending resistance and shear resistance of the plate joints are poor,and the problem of insufficient bearing capacity is exposed in the project.Therefore,it is necessary to propose a new type of node with greater bending and shear strength to meet the needs of practical engineering.At the same time,the new node is applied to the aluminum alloy reticulated shell to study the stability performance of the reticulated shell.The poor stability of the aluminum alloy reticulated shell is a major obstacle to its development in the direction of large span.Therefore,two kinds of reinforced plate-type nodes are proposed in this paper.Their mechanical properties are studied by experiments,numerical simulations and theoretical analysis.At the same time,a new type of aluminum alloy reticulated shell with prestressed cables in a quadrilateral mesh is proposed,and a new type of joint is applied to the new aluminum alloy reticulated shell for stability performance research.The main research contents and results are as follows:(1)Two new types of plate joints,ribbed reinforced and T-shaped reinforced,are proposed.Through the six full-scale joint tests,the bending resistance of the plate-type joints,the rib-reinforced plate joints and the T-plate stiffened plate joints were studied.The failure modes,joint stress distribution,ultimate bearing capacity and stiffness of the three kinds of joints are obtained.The differences in bending performance between the two joint directions of the same joint and the differences in the out-of-plane bending performance of the three joints are compared.Studies have shown that compared with the out-of-plane bearing capacity,the ribbed reinforced plate node is 1.37 times of the plate node,and the T-plate reinforced plate node is 1.5 times that of the plate node.The initial stiffness of the reinforced plate node is slightly higher than the plate node,which is about 5%.(2)Using the finite element analysis software ABAQUS for numerical simulation,the simulation results are compared with the experimental results to verify the validity of the finite element model.The influence of gusset plate thickness,web thickness,section height,flange thickness,flange width,T-plate thickness and T-plate short limb thickness on the bearing capacity of the joint is considered by parametric analysis.Based on the results of experiments and finite element analysis,the theoretical calculation method is used to calculate the ultimate bearing capacity of T-plate stiffened plate joints.It is suggested that the bearing capacity improvement coefficient of the node is 1.3,which provides effective data support for the node application space structure.Theoretical basis.(3)The reinforced plate joints are applied to the aluminum alloy reticulated shell,and the cross-cables are introduced into the two-way grid to analyze the stability of the cable-supported aluminum alloy reticulated shell.A total of 64 reticulated shell models with four spans,four span-to-span ratios,and four cross-sectional dimensions were established,taking into account the effects of cable properties,initial imperfections,material nonlinearities,geometric parameters,skin effects,and support conditions.Conduct a comparative analysis.After the crossover cable is set,the stable bearing capacity of the reticulated shell is increased by about 60%.It is suggested that the double nonlinear influence coefficient is 0.373,which is slightly better than the singlelayer aluminum alloy reticulated shell.The economic sagittal ratio is taken as 1/4～1/6,and the skin effect and the semi-rigid influence coefficient of the node are correspondingly determined by the span. |
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