FINITE ELEMENT ANALYSIS OF FATIGUE LIFE PREDICTION FOR CONNECTING ROD USING ALUMINUM AND STEEL ALLOY MATERIALS

Abstract

In an IC engine, the most heavily stressed part is connecting rod. Its functionality is connecting crankshaft and piston, which transfer energy from piston to crankshaft and converts linear piston reciprocating motion into crankshaft rotational motion. Under the engine cyclic process, the connecting rod is subjected to tensile and compressive loading. The main forces occurred on the connecting rod are forces due to maximum gas pressure and the inertia of connecting rod plus reciprocating masses. The connecting rod must have maximum stiffness at the minimal weight. This research work is focused on modeling and analysis of connecting rod stress, deformation, fatigue strength, and life prediction for Toyota Hilux diesel engine made by four candidate materials (aluminum alloy 7068T6, aluminum alloy 7050 T765, carbon steel C-40 and forged steel 4340). The connecting rod model was done by CATIA V5R20 and Numerical prediction of the desired parameters has been evaluated by considering the maximum compressive load and thermal stress using FEM (ANSYS R-19 commercially available software). According to static FEA the connecting rod made by aluminum alloy 7068T6 maximum stress concentration without thermal effects about 190.97 MPa and with thermal effects 211.87 MPa also, equivalent elastic strain 1.05e-4 mm/mm are less from steel materials. And better due to factor of safety (3.224) and mass reduction about 63.7 %. Fatigue life of connecting rod made of aluminum alloy 7068T6 without temperature effect exhibited infinite life order of 1×10P P cycles and with temperature effect exhibited about 8.1×10PP cycles are better to compared with other materials. It has been found that replacing steel made of connecting rod by aluminum alloy 7068T6 made of connecting rod, has better advantages.