Analysis Of Large Span Grid Structure With Suspended Crane And The Stress Concentration Analysis Of Welded Hollow Spherical Joints

With the development of social economy and the increase of production demand,the engineering application of large-span and large-column space structure is increasing day by day.The grid structure of welded hollow spherical joints is becoming more and more popular in large span industrial buildings by virtue of its own advantages.The increase of production scale causes the crane to run frequently,which causes the fatigue problem of the structure under the dynamic load.The stress concentration is an important factor affecting the fatigue strength of welded hollow spherical joints.In this paper,the grid structure of welded hollow spherical joints with suspension crane of large span and large cylinder net and the fatigue problem of the welded hollow sphere joints are studied and the results are as follows:1?The static analysis of the grid structure of welded hollow spherical joints is carried out with the help of Midas software.Under the action of load,each index meets the requirements of the code,and the structure has better mechanical properties.Midas software is also used to analyze the stress change of the bar when the crane is running,and the stress amplitude is obtained.2?The influence of structural details on the stress concentration factor of welded hollow spherical joints was analyzed by using ANSYS software,and the formula for calculating stress concentration factor without considering defects was obtained by regression analysis.The structural details of the nodes include:hollow ball diameter D and wall thickness T,steel tube diameter d and wall thickness t.3?The influence of defects on stress concentration factor is discussed by means of ANSYS finite element analysis software.The size of weld is too large or too small and the defect of edge cutting is considered.By changing the weld size h_f and w,the undercut depth h,the undercut width b and the undercut length l of the welded hollow spherical joints,the effect of them on the stress concentration factor of the welded hollow spherical joints is studied.The formula of stress concentration factor considering defect is obtained by regression analysis.4?Based on the stress concentration factor obtained in this paper,a fatigue calculation method for welded hollow spherical joints with hot stress amplitude as a parameter is established.And based on the previous experimental results,the fatigue checking calculation of the truss bars is carried out in this paper.