The Mechanical Properties Study On Cylindrical Reticulated Mega-structure With Semi-rigid Connections

Strictly speaking, the most connections in space structure are semi-rigid, whosestiffness falls between in completely rigid and ideal hinged. Currently, there are manyresearches on conventional reticulated shell with semi-rigid joints. As to reticulatedmega-structure, the current studies mostly focus on mechanical properties, calculationmethods, optimization analysis and seismic studies. In these studies, the connections areall regarded as ideal pinned, which ignores the joint semi-rigidity. In this paper, thestudies are aimed at the effects of joint stiffness on the structural mechanical properties.With the finite element analysis software Ansys, the numerical model of asemi-rigid connection cylindrical reticulated mega-structure was established and thecorrectness was verified. The effects of joint axial stiffness and bending stiffness indifferent order of magnitude on structural static stability were studied respectively.Their superimposed effects were put forward. The existing constitutive models of axialstiffness and bending stiffness in welded hollow spherical joint were learned. A suitableapproximation calculation method is raised. The suitable welded hollow spherical jointspecifications were chosen and their semi-rigid characters were considered. The bothstatic stability bearing capacities in full-span uniform load and half-span uniform liveload were got. By the internal forces analysis in the ultimate load condition, thestructural failure condition was got. The static analysis of welded hollow spherical jointstructure was carried out. In the end, vibration characteristics and seismic response ofwelded hollow spherical joint structure and axial semi-rigid joint structure in differentorder of magnitude were studied. The results show that the static stability capacity raises evidently with the increaseof joint axial stiffness in order of magnitude, while the joint bending stiffness has a littleeffect. In the most situation, structural damage is controlled by the strength condition, sothe material elastic and elastoplastic properties should be taken. Structural internalforces in chords increase large with the decrease of stiffness in welded hollow sphericaljoint. The suitable joints stiffness variation range has a little influence on the structuralvibration characteristics and the dynamic response, while the axial stiffness in order ofmagnitude has a remarkable one.