Buckling Load Of Thin Spherical Shells And Single-Layer Reticulated Spherical Shells

Thin spherical shells are widely used in civil engineering and other engineering branches. The structural behaviour of these structures is usually dominated by the buckling characteristics. To predict correctly the buckling load of these structures has long been a primary concern of researchers and the design engineers. In this study, nonlinear finite element modelling of the buckling behaviour of thin spherical shells was conducted using ABAQUS. It was revealed that there is a nearly-horizontal plateau in the post-bucked load-deflection curves, corresponding to a nearly-constant post-buckling load. Based on the deformation of the shell and the strain energy distribution in the deformed shell body, and combined with the theorem of work and energy, an empirical formula for the post-bucking load was derived, which can be used to predict the load-carrying capability of thin spherical shells under uniform radial load or vertical load. By means of nonlinear finite element modelling, the formula was validated.Single-layer reticulated spherical shells, integrating the advantages of both trusses and thin shell structures, are also widely used in civil engineering to cover large spaces, with load being transferred in ideal manners. The continuum analogy method was applied to single-layer reticulated spherical shells, and the formula derived was thus extended to these structures. Nonlinear finite element modelling also showed close correlation between the lower bound of the post-buckling load-deflection curves of the discrete single-layer reticulated spherical shells and the post-buckling plateau of the equivalent continuous spherical shells. This proves the feasibility of using the derived formula for thin spherical shells to predict the load-carrying capability of single-layer reticulated spherical shells. By using the idea of post-buckling load, this study provides a way to predict the load-carrying capability of both thin spherical shells and single-layer reticulated spherical shells correctly, without resorting to computer and the rather complicated software.