Research On Fretting Wear And Fatigue Of Main Bearing In Diesel Engine

Fretting damage is one of the main causes of diesel engine failure.How to predict the fretting damage of components and how to predict and improve the service life of components are the main problems in diesel engine design.The main bearing is one of the parts which are easy to be fretted in the diesel engine.Therefore,the analysis and optimization of fretting damage on the main bearing interface is of great significance to predict the service life of the diesel engine and improve the reliability of the diesel engine.In this paper,fretting damage analysis and reliability analysis are carried out on the main bearing interface of a vehicle diesel engine,and the results are optimized.Firstly,a set of finite element models for analyzing the fretting damage of the main bearing interface is established by using ABAQUS and Python secondary development,including: the whole machine finite element analysis model which can simulate the cyclic load,fretting wear analysis model based on Archard formula,fretting fatigue analysis model based on SWT parameters.On this foundation,the main bearing interface reliability model based on load-strength interference model is established.In order to verify the correctness of fretting wear analysis model,a fretting wear test-bed is designed.Through the comparison of the test and simulation results,the correctness of the simulation model and the test-bed is verified and the causes of fretting wear are further analyzed.Finally,the parameters optimization(interference,bolt preload)and structure optimization(strengthen weak area)are analyzed to improve the reliability of main bearing interface.The results show that the fretting damage can be significantly reduced by properly increasing the interference of the bearing shell or the bolt preload,and by optimizing the structural of parts like strengthening the weak area,the reliability of the main bearing interface can also be greatly improved.The research results provide suggestions and references for improving the reliability of diesel engine.