| The connecting bolts of subway tread brake unit connect the keycomponents of subway vehicle——brake unit and bogie, which are importantfor safe operation of the vehicle. These key components need to be importedfrom abroad at present. Few researches on the design techniques of these kindsof connecting bolts have been carried out in domestic. Meanwhile, a perfectdesign analysis method of the brake unit connecting bolts has not yet formed inChina. This paper aims at the problems of preload calculation, strength analysisand fatigue life prediction of a certain type of imported subway tread brake unitconnecting bolts.Varieties of load and force conditions of the structure of brake unitconnecting bolts are analyzed and the force of brake unit and connecting boltsunder various working conditions are calculated. With the criteria of preload ofconnecting bolts which is given in this paper, the bolt preload is determined.And tensile strength of connecting bolt, extrusion strength of convex platform,thread related strength of brake unit under various working conditions arecalculated and checked. The results show that structure of the connecting boltsand bolt strength are superior to domestic design.The stress-based fatigue life analysis method and the fatigue life simulationanalysis method based on ANSYS Workbench are applied. The effects of meanstress and other effect factors on fatigue characteristic are also considered. Thefatigue life of brake unit connecting bolts is analyzed. An ANSYSWorkbench-based mechanical model for fatigue life simulation analysis isestablished. And the fatigue life simulation of connecting bolts is carried out.The results show that the fatigue life of bolts is consistent with the experimentalresults, and better than domestic bolts.The analysis calculation process software of brake unit connecting bolts isdeveloped by VB computer language, and parametric design of bolts is realized. |
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