Fatigue Performance Analysis Of Space Grid With Bolted Spherical Joint And Test Of M30High Strength Bolt

Space grid with bolted spherical joint is one of the main structure formapplied to the large span construction buildings, which is increasingly extensiveapplication at domestic area and abroad. But it is a fact that fatigue problem ofspace truss structure under the suspension crane have not solved completelybecause of lacking corresponding design basis, which greatly limit itsdevelopment in the field of industrial buildings.Phenomenon of fatigue fracture of space truss structure is that the boltedspherical joints happen to rupture instead of member bars. Through makinganalysis of the whole space truss structure under the action of crane load stress,obtained facts that web members with tension, lower chords and hangingpoints using high strength bolt are feeble which inclined to under threat offatigue problem. Fatigue damage control points of structure are made lifeestimation by using the theory of cumulative damage; At the same time,research on the fatigue test of M30large diameter high strength bolts which asthe research object have carried out, getting9constant amplitude fatigue data and2amplitude fatigue data. The web members with fatigue problems havebeen verified by test, and S-N curve of M30has been obtained, which isbeneficial to establish the fatigue design method including variable of hot spotstress amplitude.Using finite element software ABAQUS， make the analysis of influencewith factors such as exposed screw thread form and number of differentdiameter on the effect of stress concentration for high strength bolt; And onthe basis of the existing network frame with high strength bolts standardoptimization design was carried out on the thread: by changing the parametersof screw thread processing, reduce the stress concentration factor of gaps, themore suitable for the thread form of suspension crane loads, achieving the goalof improving the fatigue life of space truss structure.This result of article research to improve space truss structure under theaction of a suspension crane offer reference to the fatigue properties of highstrength bolt, as well as related provides an important theoretical basis forrevision of the norm.