Cumulative Microslip in Conrod Big End Bearing System

High combustion gas pressure and mass reduction of modern automotive engines have generated new problems in mechanical assemblies. For example, it is now common to observe bearing shell rotation in the conrod of automotive prototype engines at the design stage. The consequence is sometimes the seizure of the bearing due to the presence of the joint face relief in the loaded area. Physically, the bearing shell rotation results from cumulated microslip between the bearing and the conrod. To have a better physical approach of the phenomenon and propose design recommendations, we have performed analyses based on the strength of material theory and numerical modellings. These tools permit us to obtain simple models allowing an easier mechanical understanding as well as an analysis of sensitivity to different parameters. The main results presented in this paper are: • The basic description of the phenomenon, • The modelling of the conrod, its sensitivity to deformation and numerical validation, • The analysis of the microslip between the bearing shell and the conrod, • The sensitivity analysis with respect to conception and physical parameters.