Hassan Sayyaadi - Professor, School of Mechanical Engineering, Sharif University of Technology, Azadi Avenue, Tehran ۱۱۱۵۵-۹۵۶۷, Iran
Mohammad Erfan Khodabakhshi - B.Sc. Student, School of Mechanical Engineering, Sharif University of Technology
Maryam Hoviattalab - Lecturer, School of Mechanical Engineering, Sharif University of Technology

Today, vehicles are one of the most widely used human needs in the present age and have helped human to do their various objects easily. The main concern of car designers is always to design and build cars that have the best performance in terms of aerodynamics, proper engine power, low fuel consumption, smooth suspension system and etc. On the other hand, the limitations that exist in the manufacturing processes cause the samples designed by them to not reach the final stage of produc-tion as they should, and inevitably make changes to them that reduce their performance despite the easier manufacturing process. In this research, we will research on the main part of car power gen-eration, which is the crankshaft and is one of the most expensive car parts (due to its difficult pro-duction process). The phenomenon of vibrations in mechanical systems is one of the biggest prob-lems and obstacles in the design of mechanical devices. The subject of this study is the analysis of mechanical vibrations of the crankshaft of a 4-cylinder engine.Firstly, we design a sample of a crankshaft and then by mathematical concepts, calculate the vibra-tion forces of each piston which transfer to crankshaft by connecting rods at different speeds. then in ABAQUS software, analyse it in terms of forced vibrations and free vibrations.Finally, we discuss about the quality of the designed model and its suitability, and then suggest some solutions to increase the useful life of the crankshaft and improve its performance.

Vibration; Crankshaft; Connecting rod; Piston