Finite element analysis of fatigue in the connecting rod of a spark ignition engine based on results of combustion tests

The connecting rod is a crucial component in internal combustion engines (ICE), serving as the link between the piston and the crankshaft and facilitating the conversion of linear motion into rotational motion. This component is subjected to alternating compressive and tensile stresses, as well as buckling stresses, making a comprehensive assessment of fatigue failure imperative. Based on combustion test results, this study presents a finite element analysis of fatigue in the connecting rod of a spark ignition engine utilizing C3D10 material. Numerical analyses that focused on tensile stress and fatigue failure were conducted using ABAQUS and FEMFAT software, with results compared to test data obtained from actual connecting rod samples to validate the findings. The static analysis identified critical points of Von Mises stress under tensile and compressive loads, revealing significant variations in stress concentration locations and geometries. The maximum tensile stress was observed at the piston pin, while the minimum stress occurred at the crankshaft pin. Notably, the most pronounced stress concentrations were located at the small end of the connecting rod, particularly at the interface with the piston pin, where a maximum deformation of 1.35 mm was recorded. These findings highlight the relationship between critical stress areas and actual failure locations in the tested samples, providing valuable insights for improving the design and reliability of connecting rods in ICE applications.