Fatigue Life and Stress Analysis of a Single Cylinder Four Stroke Crankshaft

Abstract

This paper focuses on the optimization of a crankshaft using ANSYS software in terms of weight and strength. The initial designs of the crankshaft, piston, and connecting rod were created using SolidWorks. The force generated by the gas during the combustion process was calculated to be 12017 N. Next, the SolidWorks assembled system was imported into ADAMS View software for simulation, which revealed a time-variant force of the crankpin of 14049 N. The calculated value was verified with results obtained from analytical calculations, showing a deviation of 0.23%. Finite element analysis was done for the crankshaft using ANSYS transient structural after applying loadings and boundary conditions. The optimization process aimed to minimize the crankshaft's weight while maintaining its strength and durability. The results of the ANSYS simulations showed a weight reduction of 2.5% from the original 2.983 kg to 2.907 kg, while maintaining the required strength and durability. The optimized crankshaft was compared to its original design in terms of fatigue life, weights, and stresses. The maximum von Mises stress was reduced by 16%, shear stress by 3.5%, and deformation by 3.5%, which were validated through analytical calculations. The crankshaft analysis resulted in a significant increase in fatigue life, calculated to be infinite under the given conditions. To conclude, the objective to optimize the crankshaft for performance and efficiency was achieved, demonstrating a 2.5% weight reduction and substantial improvements in fatigue life and stress distribution, proving the effectiveness of ANSYS software for the design optimization process.