Analysis And Experimental Study On Fatigue Properties Of M30 High Strength Bolts In Grid Structure

Grid structure occupies an i MPortant position in the form of large span architectural structures, Grid structure with bolt spherical joints, that is convenient, fast and easily disassembled to constructionandothercharacteristics, has been widely used in domestic and abroad public buildings, industrial plants and other large span buildings. But when the grid structure with bolt spherical joints set suspended crane, will produce fatigue in crane hanging reciprocating under alternating loads, fatigue failure may even occur. In China’s relevant regulations in the design specification grid structure with bolt spherical joints fatigue design is still blank, designers have no basis, which greatly limits the grid structure with bolt spherical joints future development applications.In this paper, calculated by means of theoretical analysis and experimental research on the suspended crane set bolts ball grid plate M30 high-strength bolts in the fatigue properties of a series of research and analysis, the main research contents are summarized as follows:1. Using ABAQUS finite element software for the study of different forms of thread were modeled of M30 high-strength bolts, analyzed the differences between their calculation of stress concentration factor and pattern modeling for different numbers exposed tooth, analysis calculate the difference between the stress concentration factor between them. There are different processing technology of high strength bolt was studied as well as corrosion and cyclic load to the influence of the fatigue performance and proposed to i MProve the fatigue resistance of high-strength bolts measures. 2. Using the MTS fatigue testing machineconductfatigue performance of M30 high-strength bolts were a constant aMPlitude and variable aMPlitude fatigue tests, get 90 MPa, 100 MPa, 120 MPa, 130 MPa, 140 MPa, 150 MPa, 160 MPa, 170 MPa, 180 MPa, 190 MPa, 200 MPa, under 210 MPa stress aMPlitude, a total of 37 constant a MPlitude fatigue data, and get the corresponding SN curve, but also on the M30 high-strength bolts fatigue performance under variable aMPlitude loading conducted experiments and obtained the appropriate SN curve and to study the mechanism of fatigue failure.3.With the 3D3 S software developed by Tongji University, for modeling and analysis against a set of suspended crane bolt ball grid plates, analyze the bolt ball grid bars and the maximum displacement stress distribution under different load combination to find out the same bars and high-strength bolts the maximum stress and minimum stress under different load combinations, in particular analyzes the M30 high-strength bolts in different conditions of stress aMPlitude loading crane.