Life Prediction And Reliability Analysis Of Aero-Engine Rolling Bearing Considering Temperature And Lubrication

Aero-engine is the source power of the development of aviation industry.Because of the particularity of aviation field,it is required that aero-engine always has high reliability and safety.Rolling bearing is the most important rotating part of aeroengine,its working environment is strict and complex,and under the combined action of a variety of loads,which causes the rolling bearing is prone to fatigue failure in the working process.In order to ensure the safety and improve the overall performance of aeroengine,it is necessary to accurately predict the life of rolling bearings.Because the aero-engine rolling bearing is always in the complex and changeable working environment,it is required to analyze the accurate mechanical characteristics of the rolling bearing.There are some problems in the existing research on rolling bearings.For example,the analysis mainly adopts the static analysis method,without considering the inertia force of bearings in the actual working process.When analyzing bearing lubrication performance,the calculation of minimum film thickness is not accurate enough.The results of the existing deterministic fatigue life prediction methods are quite different from the actual ones.In view of these problems,thesis carried out research on rolling bearings,the main research content is as follows:(1)On the basis of statics,considering the centrifugal force and gyroscopic moment produced in the running process of bearing,a bearing contact analysis model was established by bearing deformation coordination equation.The minimum oil film thickness is modified considering the influence of inlet heat effect.Through the model,the contact stress value of each position Angle of the inner and outer rings of the rolling bearing is obtained accurately under certain working conditions.(2)Considering the effect of average stress on material life,a life prediction model modified by average stress is adopted.Due to the different materials of the parts,the sensitivity of the materials to the average stress is different.According to the sensitivity of the same type of material,the life model is modified,and the fatigue life of the rolling bearing under certain working conditions is solved.(3)Considering the influence of uncertain factors,the parameters in the fatigue life prediction model were converted into random variables,and the probabilistic fatigue life prediction model of rolling bearings was obtained by calculating the bearing life.The rolling bearing reliability model was established based on the stress-strength interference model,and the rolling bearing fatigue life distribution calculated from the probabilistic fatigue life prediction was combined to draw the curve of reliability change with the design life.