Research On Rigidity Of Circular Tubular ZYY-joint In Single Fold Surface Of Multi-planar Steel Structure

Nowadays, because of the unique advantage, tubular structure is widely used in space structure. With the development multidimensional numerical control incision technology and design software for tubular structures, unstifffened tubular joints, which are usually configured by welding one member directly to the surface of the other, are more and more adopted at connections between hollow section members in tubular structures. However, the loaded braces always cause local distortion of the chord cross-section and hence displacement and rotations of the ends of the braces relative to the chord axes. Stiffness behavior of this kind of joints will redistribute the nominal stresses, increase the deflections, and influence the buckling loads of steel tubular structure.At present, analysis of tubular joints is based on some experiments and theoretical analyses. In this paper, the rigidity analyses by test and general finite element software are applied for the multi-planar circular tubular ZYY-joint, which is scaled by 1:3 ratio of the acrominon joint in the main stadium of the 26th University Games in Shenzhen City, in 2011.Firstly, this paper introduces the stress-strain relation of steel, describes the deformation mechanism of circular tubular joint and defines the rigidity of circular tubular joint on the basis of numerous references. Then the geometry which affected the circular tubular ZYY-joint rigidity is identified.Subsequently, test anslyses are conducted on the model of the acromion joint in the main stadium of the Shenzhen Universiade. Comparing the results between test and finite element analysis of two kinds of circular tubular joint whose chord with or without stiffener on the deformation of the joint region, the failure mode and Mises stress provides a reliable basis for using the finite element software for the analyzing the rigidity of joint.In the end, the changes of the rigidity of multi-planar steel circular tubular ZYY-joint on the differences of the angle of chord, the brace to chord diameter ratio, the ratio of diameter to thickness, the brace to chord thickness ratio, the angle between brace and chord, the brace to chord planar angle are simulated and analysed by nonlinear finite element method using ANSYS10.0. And the calculation formula of multi-planar steel circular tubular ZYY-joint is educed by using Excel software to the joint between its rigidity and impact parameters for the 95% confidence level multiple linear regression analysis, which is brought forward for the actual project design.