Stress Concentration Analysis And Fatigue Preformance Test Of High-strength Bolts In Bolted Spherical Joints Grid

With the high-strength bolted ball node grids gradually being put into the construction applications of a large number of industrial plants,their fatigue problems occur due to the reciprocating action of the suspended cranes.The stress concentration phenomenon is an important cause of the fatigue source that causes fatigue failure.It is of practical significance to study the fatigue strength and stress concentration of bolted ball joints with high-strength bolts.The specific research work and conclusions of this article are as follows:1.Using ABAQUS finite element analysis software,the high-strength bolts were studied and the stress concentration factors of the high-strength bolts were studied from the four aspects of thread form,bolt diameter,bolt ball size,and fillet radius of the teeth.The formula for calculating the stress concentration factor of high strength bolts.2.Using ABAQUS finite element analysis software,the high-strength bolted porous bolts were used as the research object,and the stress distribution of bolt-ball joints under the multi-axial loads was analyzed.3.Amsler fatigue testing machine is used to complete the constant-fatigue test of bolt-ball nodal plane truss.The test data of 24high-strength bolts are obtained,and the reasons for the discreteness of the data are analyzed in detail.4.Microscopic analysis of fatigue fractures of high-strength bolts was performed by electron microscopy scanning to reveal the mechanism of the normal-range fatigue failure.