Fatigue Life Prediction And Reliability Analysis Of High-speed Train Axle

High-speed train obtained the development which progresses by leaps and bounds,with its fast,comfortable,safe,large volume,low energy consumption advantages.Axle is an important part to ensure the normal operation of high-speed train,bearing a variety of load from the body and the track,and its surface machining quality and heat treatment conditions will lead to fatigue failure of the axle.In order to ensure that the axle has sufficient safety,reliability and long service life under the specified conditions of use,it is proposed that the axle material should be put forward very high requirements.In this dissertation,main work is fatigue life prediction and reliability analysis aimed at high-speed train axle material medium carbon steel.The specific work content is as follows:1.Rotating bending fatigue test were carried out on medium carbon steel specimens with different surface roughness.After processing the experimental data,it was obtained that S-N curve and the confidence limits for the overall safety and reliability life P-S-N curve of medium carbon steel specimens with different surface roughness.2.Rotating bending fatigue test were carried out on medium carbon steel specimens with different heat treatment conditions.After processing the experimental data,it was obtained that S-N curve and the confidence limits for the overall safety and reliability life P-S-N curve of medium carbon steel specimens with different heat treatment conditions.3.Fatigue crack propagation process of medium carbon steel specimen was studied according to fracture mechanics knowledge.Based on the first two parts of the test data,it was deduced that fatigue life prediction model of medium carbon steel specimens with different surface roughness and heat treatment conditions.4.Taking axle of CRH5 type EMU as an example,the force condition of the axle is analyzed.Considering random variables such as elastic modulus,shear modulus,surface defect size,nominal radius of wheel rolling circle,etc,The reliability and the reliability sensitivity of the medium carbon steel axle were analyzed on the condition of Ra=0.4 and tempering temperature of 500 degrees Celsius.Based on the experimental data,these research works could deduce fatigue life prediction model of medium carbon steel specimens with different surface roughness and heat treatment conditions and obtain the reliability and the reliability sensitivity of the medium carbon steel axle via combining the model and the actual situation of the axle of the CRH5 type EMU.It provides an effective basis for the overhaul and maintenance of the axle.