A refined finite element analysis on single layer latticed domes with welded hollow spherical joints

The nonlinear analysis of the refined FEM structural model of a K6(2) latticed dome considering geometrical nonlinearity and material elasto-plasticity was carried out using the SHELL181 element of ANSYS software to simulate steel tubes and spherical joints.By comparing the refined analysis with traditional beam element analysis,the refined results of plastic stress distribution,detailed failure modes and limit loads were obtained.By conducting the parametric analysis,influences of the impacting factors such as thickness and diameter of welded hollow spherical joint,structural initial imperfection and the welding defects were discussed.The research indicates that only when the ratio of spherical joint thickness to the tube thickness exceeds 1.5 as required by the 'Technical specification for latticed shells',the spherical joint can be considered as a rigid node.The diameter of a spherical joint does not affect the limit loads of the dome,while it will change local instability pattern.The results from traditional beam element model and refined shell element model are consistent in terms of the influence of the initial imperfection.The material strength of welds only affect the plastic distribution at spherical joint and tube connecting region.The welding defects will reduce the limit load of the dome sharply.