Spalling investigation of connecting rod

The customers of the vehicles reported high noise and vibration in the engine at an early stage of service lifetime. An analysis of the various components of the internal combustion engine was carried out. Subsurface cracks and pit marks were seen in the crank pin, roller bearings and big end surfaces of the connecting rod. It was found that high wear at the interface of these components was the main culprit. A laboratory test set-up was developed to correlate and reproduce the field failures. The loads and boundary conditions obtained from the experiments were used in the finite element model of the connecting rod assembly. Results shows high interfacial pressure and stresses near the junction of web and flange of the connecting rod. The modified design of the connecting rod shows significant reduction in the extreme pressure in FEM resulting in the significant enhancement of durability life in laboratory test. A discussion of the spalling problem has been provided leading to the connection of pick pressure and spalling phenomena.

► Spalling in the connecting rod can resulting high noise and vibration of engines
► High interfacial pressure and stress in the contact patch zone accelerate spalling and lower durability life
► Design of connecting rod web results in decrease in pressure spike in the contact patch region
► Reduced magnitude of high pressure enhances bearing life of connecting rod.