The Influence Of The Joint Stiffness On The Stability Of Single-layer Spherical Latticed Shells

Reticulated shell is a space structure system that is made up of members regularly arranged along a surface. Owing to prominent properties, such as reasonable mechanical properties, high rigidity, large-span space covering, and so on, it become a primary kind of structural types of large-span spatial structures. The span and size of latticed shells tend to be large, which result in stability problems more and more remarkable. Recently, the researches of the stability effect factors of latticed shells mainly focus on their type, size, load condition, and initial geometrical imperfection, but seldom on the joint stiffness. The joints of single-layer latticed shells are usually assumed to be completely rigid in the traditional design method, which remains to be proven.In this paper, the stiffness calculation methods of the welded hollow spherical joints are presented. The influence of the joint stiffness on the stability of single-layer spherical latticed shells is researched, including rib-patterned spherical latticed shells, K6 spherical latticed shells and Lamella spherical latticed shells. In the analysis, the stability effect factors of latticed shells such as the original geometrical imperfection, the span and the ratio of rise to span are also considered. The linear and nonlinear buckling analysis of single-layer spherical latticed shells with joint stiffness is carried out using ANSYS to obtain the eigenvalues, the buckling modes and the load-displacement graphs, according to which the influence of the joint stiffness on the stability of single-layer spherical latticed shells is evaluated.In the conclusion, the influence of the welded hollow spherical joints stiffness on the stability of single-layer rib-patterned spherical latticed shells is greater than that of the single-layer K6 and Lamella spherical latticed shells. Compared with the single-layer spherical latticed shells with the rigid joints stiffness, the collapse load of the former decreases to 75%, and the latter two respectively decreases to 88% and 89%. So the supposition in the traditional design method is not appropriate to all the single-layer latticed shells, the influence of the welded hollow spherical joint stiffness on the stability of single-layer latticed shells should be paid great attention to.