Fretting Fatigue Damage Research Of LZ50Axle Steel

Wheel set that as one of the key components of the locomotive which is composed oftwo wheels and an axle and combined by interference fit, it under the full weight of the train,the part of interference fit is the fitting surface of axle wheel seat and wheel hub. Cyclic loadsof speeding axle are intensified, because there are fretting damages in connected parts and thatdamages gradually accumulated under the long-term effects of random load to a certaindegree caused fatigue fracture, a serious safety hazard. Axle is directly related to railwayvehicle driving safety, the fracture of it would lead to vehicle derailment，so axle fatigueproblem always attaches great importance to by the railway department. In order to eliminatethe security hidden danger existing in the transportation, need to analyze the axle frettingfatigue.At first, this paper uses the finite element method (FEM) analysis the contact of themicro bridge model, the analysis of the micro bridge fretting fatigue specimen surface, the3dgeometry model and finite element model is established, and through the finite elementsoftware ABAQUS was carried out under the different parameters of the static calculation.Based on the calculation results, using the method of contact surface is introduced to therelative displacement and the use of the relationship between the maximum static frictionforce and tangential force two ways to judge the state of the contact area; Cyclic load, themicro bridge pressure, the coefficient of friction and micro bridge foot radius parameters onthe stress distribution, specimen surface contact state.The result calculated by finite element software ABAQUS and the energy densitymethod is introduced, through the analysis of the critical surface damage factor distributionalong the contact path to predict surface fretting crack initiation location under differentparameters. According to the theory of multi-axial fatigue strength, establish a model forestimating the fatigue life. The fatigue testing machine for micro bridge fatigue tests werecarried out, it is concluded that the stress-life curve, fitting for life prediction formula for axlelife prediction model of steel, and compared with the life that the SWT method predict. Byanalyzing the wear behavior of micro surface, the mechanism of crack initiation is studied.With CRH2bullet train axle and wheel as the research object, the axle interference fittedof elastic mechanics is analyzed and finite element analysis is evaluated and the effect ofinterference quantity of shaft is analyzed. The relative slip of shaft interface and micro damage is discussesed, according to fatigue life prediction model to predict crack initiationlocation and life, found that the predicted crack initiation location and life have goodconsistency with the actual situation, on the train safe operation and determine themaintenance cycle has important guiding role.