Evaluation of fatigue performance of a fillet rolled diesel engine crankshaft

This paper summarizes an investigation of the effect of fillet rolling on fatigue behavior of a ductile cast iron crankshaft used in diesel engine applications. Based on the staircase test methodology, resonant bending fatigue tests were conducted to obtain stress versus number of cycles curves and to evaluate the fatigue endurance limits of ductile iron crankshaft under fillet rolled and un-rolled conditions. The corresponding stress levels on the fillet region by the applied test moments were calculated by the finite element modeling of the crankshaft test rig. Test data was analyzed by Dixon–Mood method to calculate the endurance limits. Fracture surface examination was conducted macroscopically and by scanning electron microscope. Fatigue endurance limits measured for un-rolled and rolled crankshafts are 201 MPa and 811 MPa respectively, emphasizing a significant fatigue endurance limit improvement by fillet rolling process.