The Study Of Equivalent Finite Element Of Welded Hollow Ball With A Crack

With the development of large span spatial steel structure, Welded hollow spherical joints are increasingly applied in single layer latticed truss structure. The crack is easy to appear in the production and working process for welded hollow spherical joints. Cracks causes structural injury, welded hollow spherical joints was semi-rigid. The content of this paper is mainlyabout how to simulation the semi-rigid of welded hollow spherical joints by finite element analysis, which is caused by crack in the weld zone.The main content and steps are as follows:(1)Based on the crack theory, establish the fine model of welding hollow ball with a crack by using ANSYS finite element software.(2)Loading on the fine model of welding hollow ball with a crack, get the axial stiffness coefficient and bending stiffness coefficient by processing data.(3)Processing data by MATLAB software,get function relation between different crack size and axial stiffness coefficient,bending stiffness coefficient by curve fitting method.(4)Welded hollow ball with a crack is semi-rigid, it has two ways to realize it. One is modifying the parameter of beam element’s stiffness matrix.Another is to find the semi-rigid joint equivalent element. This paper uses the Matrix27elemen as the equivalent element, Established equivalent model of welded hollow ball with a crack.(5)Verify the validity of the equivalent model by two rigid frame structures and a truss structure.When a crack of welding hollow ball with a crack gived, a equivalent model of the joint can be established.