Bi-Axial Fatigue Of T Joint Of Corrugated Plate

At present,the fatigue details of T joint of corrugated steel plates have not been clearly specified,and the fatigue has become the focus of researchers.There is a lack of relevant research on the construction form of combining corrugated webs and suspension monorail track beam.Under the action of train load,the T joint between corrugated plate and flange of the new suspension track beam(corrugated webs)is in the plane stress state of biaxial tension,and the resulting fatigue damage cannot be referenced from previous studies.In this thesis,a new type of suspended monorail track beam(corrugated webs)is taken as the engineering background to study the fatigue behavior of T joints of corrugated steel plates under biaxial tensile load.The main research work is as follows:(1)The finite element model of linear beam of 30 m new type suspension monorail track beam is established.The model adopts the form of multi-scale semi-structure,and the radius of arc section of corrugated web is R = 150 mm,and the wave angle is 36.5°.The bi-tensile stress effect of the T joint of the web and the bottom plate of the new track beam under train load is obvious,which cannot be considered only according to the uniaxial stress state.The most unfavorable point of stress is located in the arc transition section.(2)According to the life consistency of the key details,the biaxial fatigue test of the new suspension track beam was designed and carried out.The hot spot stress method was used to analyze the test results of the T joint between the corrugated web and the flange under bi-tensile load.In addition,the radius of arc segment and wheel load position have great influence on the stress state of T joint of corrugated webs.(3)According to the bi-parameter W(?)hler curve method based on critical distance theory determined by FAT125 and FAT80 standard curves in Eurcode 3,the fatigue evaluation of T joint of corrugated steel plate is too conservative.When the radius of circular arc section of 30 m linear beam corrugated web changed from R = 150 mm to R = 300 mm,the fatigue life at the most unfavorable point of weld toe increased by 87 %.