Static Stability Analysis Of Partial Double-layer Kiewitt-8 Ribbed Spherical Reticulated Shells

The reticulated shell structure is a kind of spatial structure,which has been widely used in the present structure because of its advantages of good mechanics performance,saving materials,light weight,simple construction and beautiful appearance.With the development of industrial techn ology,a large number of new reticulated shell structure forms and shapes have emerged.Based on the loading condition of reticulated shell structure,the internal force of the bar is mainly axial force,so the stability problem is a key problem in the des ign of the shell structure.The grid of reticulated shell structure is diverse,this paper mainly studies the case of the Kiewitt-8 spherical reticulated shell,which has uniform grid size,few kinds of bars,superior force performance,and it is widely used in engineering.Considering that the stability performance of single-layer Kiewitt-8 spherical reticulated shell is poorer,while the two-layer Kiewitt-8 spherical reticulated shell has too many nodes and rods,using the large amount of steel,therefore,according to the mechanical characteristics of single-layer Kiewitt-8 spherical reticulated shells,adding web members,chord rods and brace rods in the radial main rib which is the main load-transfered path of single-layer Kiewitt-8 spherical reticulated shells,thus forming the partial double-layer Kiewitt-8 ribbed spherical reticulated shell,this kind of spherical reticulated shell structures has high rigidity,reasonable stress distribution,concise and esthetic shape,economical rationality,which has a certain value of engineering application and research.In view of the stability research of the partial double-layer Kiewitt-8 ribbed spherical reticulated shells is less,in this paper,the static stability problems of this kind of spherical reticulated shells are studied in depth.Firstly,the stability performance of the partial double-layer Kiewitt-8 ribbed spherical reticulated shell and the single-layer Kiewitt-8 spherical reticulated shell are compared and analyzed.The results show that the partial double-layer structure along the radial main rib is effective in improving the mechanica l performance of the shell,and it is an economic and reasonable strengthening form of the single-layer Kiewitt-8 spherical reticulated shell.Then the stability analysis of partial double-layer Kiewitt-8 ribbed spherical reticulated shell is carried out by means of extensive parametric analysis.The effects of parameters such as thickness of the partial double-layer structure,sizes of the member sections,rise-span ratio,grid size,nodal connection of the partial double-layer structure,asymmetric loads and initial geometrical imperfection on the geometrical nonlinear stability of the spherical reticulated shells are included.Finally,based on the analysis of the elastic stability of the structure,the effect of material nonlinearity is introduced,the elastoplastic buckling of the partial double-layer spherical reticulated shell is studied,and the effects of initial geometrical imperfections,asymmetric loads and support constraints on the elastic-plastic stability of the structure are considered.According to the structural plastic development and structural instability forms,the rational design of member sections is carried out.