Study On Elliptical Suspendome Based On The Stiffness Of Reduced-diameter Welded Hollow Spherical Joints

Elliptical suspendome is one of the development direction in the future of suspendome because of its good mechanical properties and flexible design.The joints of elliptical suspendome are mostly welded hollow spherical joints,and the welded hollow spherical joints are semi-rigid.Members are welded on the welded hollow spherical joints.If the diameter of hollow sphere is small,the distance between members is too small to divide every members;if the diameter of hollow sphere is large,the amount of steel used in the structure and the difficulty of construction will be increased,and the beauty of the structure will be affected.The reduced-diameter welded hollow spherical joint is proposed in this paper;the bending stiffness of joints are studied;the influence of reduced-diameter welded hollow spherical joints on the elliptical suspendome is discussed.This paper combines with an engineering example of elliptical suspendome,which shows that the bending stiffness of joints will affect the mechanical properties of elliptical suspendome.The research results of bending stiffness of welded hollow spherical joints are summarized,and the influence of reduced-diameter on welded hollow spherical joints is introduced.On this basis,the research contents of this paper are put forward.The moment-rotation curve and bending stiffness of reduced-diameter welded hollow spherical joint are measured and calculated by the scale test of reduced-diameter welded hollow spherical joint.The finite element software ABAQUS is used to establish models and calculate them.The results of the tests and finite element simulation are compared to verify the accuracy of the finite element models.It is found that the ratio of the diameter of the small diameter end to the diameter of the ball has the greatest influence on the bending stiffness of the reduced-diameter welded hollow spherical joints,followed by the ratio of the thickness of the ball to the diameter of the ball,and the length of the vertebral canal has the least influence.A accurate formula for calculating the bending stiffness of reduced-diameter welded hollow spherical joints is presented,and the accuracy of the formula is verified by the calculation of finite element models.In this paper,the mechanical properties of reduced-diameter welded hollow spherical joints under pure bending moment are also studied.It is found that the mechanical properties of reduced-diameter welded hollow spherical joints under pure bending moment are similar to those under bending loading state.The formula for calculating bending stiffness can be used for reduced-diameter welded hollow spherical joints under pure bending moment.Based on the research of bending stiffness of reduced-diameter welded hollow spherical joints,the finite element models of reduced-diameter welded hollow spherical joints are established by using various modeling ANSYS methods.A modeling method with accuracy and efficiency is found,that is,two connected vertebral canals are used to simulate reduced-diameter welded hollow spherical joints.It is found that the reduced-diameter welded hollow spherical joints will weaken the mechanical properties of the elliptical suspendome structure,but the influence is small,and the steel consumption can be reduced by using the reduced-diameter welded hollow spherical joints.The conclusion is of guiding significance and reference for the design of elliptical suspendome.