Hollow Transmission Shaft Plug Welding Hole Fatiue Analysis Methods And Applied Research

The longitudinal traction and iMPact load of internal combustion engines andvehicles in our country has increased rapidly as the constantly breakthroughs weremade in the direction of heavy load and high speed. however, the fatigue problems ofthe vehicle key parts appear ceaselessly, which bring great challenges to the reliabilityand safety in the railway operation process. Because of many fatigue fracturephenomenon have found in the process of return period of maintenance on DF_4B typediesel engine car transmission shaft, so the problem has aroused people's attention. Toassure the shaft can be used normally, it is necessary to do fatigue strength checkingand life prediction to the main components hollow shaft of transition shaft.This research object of the paper is based on DF_4B type diesel locomotive dieselengine hollow shaft, the two-dimensional model of hollow shaft was established, FEAsoftware, the proportion of the finite element method, the hollow shaft of the plugweld hole. Analysis of the plug welding the hole in the aspect ratio of differentdiameter and different matching coefficients of stress concentration factor, andanalyzed the plug weld holes around normal stress distribution.Setting the plug hole hollow tubular with material of Q235 as example, forexample, twisted with the stress ratio R =-1, consideration of the gap, size and surfacequality coefficient factors, based on material S-N curve of different theories, the stressconcentration factor under the S-N curve, The machine through the torsional fatiguespecimens with holes in the experiment, the hollow shaft torque under differentfatigue cycles N, proved hollow shaft fatigue properties and calculating.According to the actual material for the hollow shaft 20CrMnTi, the hollow shaftin the case of plug welding is not carried out static strength check, indicating that thehollow shaft to meet strength requirements. Consider the size of the hole in the plugwelding in the case of D = 10mm, the use of sub-model interpolation method provedhollow shaft stress concentration factor increases with the matching coefficient is firstdecreased and then increasing. Based on the actual load conditions on the hollow shaftto check the safety factor, safety factor and allowable coMParison, the hollow shaftfatigue damage can happen. Then calculate the matching coefficients of differenthollow shaft fatigue life under the results show that the hollow shaft the greater thestress concentration factor of more prone to fatigue failure, the greater the damage.