Theoritical Analysis Of Collapse Mechanism And Bearing Capacity Of Cast Steel Node

Numerical analysis of the cast steel hollow spherical node under different loadforms is carried out systematically and roundly for the requirement of development ofthis kind of node. Nonlinear elasto-plastic FEM analysis of 48 nodes with differentspecifications under compression, tension and moment are performed through largegeneral-purpose FEM program ANSYS7.0. Based on the results of these analyses thedistribution of the stress, the process of plasticity spreading, the failure mechanismand ultimate load of this kind of node are presented. The influences of differentparameters to the ultimate bearing capacity in compression, tension and moment arededuced by the comparison of results of the ultimate load of those 48 nodes.According to these results the bearing capacity formula of this kind of node isdeduced by the linear regression method depending on least squares theory. Designercan consult the formula when the decide to use this kind of node. The nonlinear FEManalysis of bearing capacity of some nodes under axial force and moments are done.The process of plasticity spreading and ultimate bearing capacity of this kind of nodeunder axial force and moment are pointed out. The ratio of ultimate bearing capacitiesunder common load and individual load is seemed as the point in the rectangularcoordinate system. And the regression formula is deduced depended on those points inthe rectangular coordinate system for the reference of the design of this kind of nodeunder common load. Finally, the paper provides the checking computations of themost dangerous cases of the cast ball-and-socket support node planned to be use in thedouble-layer reticulated dome roof of Laoshan Cycling Gymnasium for BeijingOlympic Games. The node under most dangerous cases is analyzed by ANSYS7.0 toget the distribution of stress and assurance coefficient. All these results can be thetheoretical warranty for the use of project of Beijing Olympic Games...