Research On Fatigue Reliability Of CRH5 EMU Wheel Under Random Load

High-speed EMUs are running at a faster speed nowadays,for some of the recently built lines,the working environment is harsh,and the safety and reliability requirements is rising.The wheels are key components of a high-speed EMU.As one of the most important forms of failure to the wheels,fatigue damage plays a decisive role.In order to ensure that the fatigue performance of the wheels can meet the using conditions and further maximize the lifetime of the wheels,it is necessary to study the fatigue reliability of the wheels.Basing on the study,an improved wheel repair plan should be proposed,and this piece of work can extend the service life of the wheels.The parameters used in this article is taken from the CRH5 EMUs running on the Harbin-Dalian railway.Considering the influence of low temperature conditions on the suspension of the CRH5 EMU bogie,a vehicle-orbit dynamics model is established to simulate the wheel load spectrum under three working conditions.With the finite element model(FEM),the stress response of the wheel under different loads is analyzed,in order to determine the dangerous point of the wheel and the stress change with the load.The stress history of the dangerous point is extracted,when the wheel rotates for a full circle.During the study,the relationship between the load and stress shows a quasi linear characteristic.So the stress corresponding to the dangerous point of the wheel is obtained by linear regression method and the date is corrected by the Goodman average stress correction method.Then,the stress is converted into equivalent damage by the material S-N characteristic relation to obtain the corresponding equivalent damage distribution under the three different working conditions.The wheel fatigue reliability is calculated by using the central limit theorem and the sampling distribution of the sample mean.Taking the point on the path of the dangerous point as the research object,calculate the damage accumulation of each point during the repair process,and obtain the fatigue life of the wheel under different repair plans.Study the repair strategy within 20 times,analyze and compare the effects of different repair intervals,repair depths,and repair times on wheel fatigue life.Using the central limit theorem and normal distribution characteristics,a method for calculating the fatigue reliability of wheels under different repair plans is proposed.Compare and analyze the maximum fatigue life of the wheels under different repair times,when the repair plan requires the fatigue reliability is greater than 99.99%.The research can evaluate the fatigue reliability of the CRH5 type EMU wheels on the Harbin-Dalian railway under extreme cold environments.It can provide an optimized wheel repair strategy while ensuring the wheel fatigue reliability.