Effect on Fatigue Behavior of Connecting Rod in Gasoline Engine

Abstract

This article reports the failure analysis of a connecting rod that is broken into 3 pieces and is used in the gasoline engine of a sedan. The connecting rod is made of JIS-S50C medium alloyed steel. Fractography was performed to characterize the failure mode on the fracture surface of this connecting rod through the examination of the macroscopic and microscopic morphologies of the fracture surface, chemical composition, metallographic analysis, mechanical properties of the material, and numerical simulation. The fracture surface of this connecting rod is caused by fatigue, which was the dominant mechanism of failure. This type of crack is indicative of shear failure in the ductile fracture mode, whereas no abnormalities were found in the composite elements of the connecting rod. The microstructure is composed of perlite-ferrite. The results of the numerical simulation and the calculated crushing stress (sc) were compared and were found to be in accordance and within the acceptable values.