Test Research On Fatigue Behavior Of Gird Structure With Bolt-sphere Joints

The gird structure with bolt-sphere joints is most widely used in our country presently; the fatigue under suspended crane loading is paid attention to scholars extensively in recent years. Particularly there haven't rules on the fatigue in . (JGJ7-91), so designers haven't references in fatigue design, the gird structure's application in the workshop is restricted seriously.The fatigue of gird structure with bolt-sphere joints is mainly the fatigue of High strength Bolt. The fatigue behavior of M2(K M3CK M39 High-strength Bolt is researched by lots of equal amplitude and variable amplitude fatigue experiments in this paper. All experiments were completed by use of loading equipment designed by myself. This equipment has been proved to be efficient, steady and the test data are reliable. Based on analysis of the 58 data and 35 domestic data, we got the S-N curve in general use, and established the design method of fatigue. Moreover, the influence factors of stress ratio, intermittent time, loading order etc. to fatigue strength were discussed.I believe that the research result of this paper will become importance basis to the specification's revision.