Mohsen. Khoshbayani Arani۱ - Phd student, Department of Mechanical and Aerospace Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
Nima Rasekh Saleh۲ - Phd student, Department of Mechanical and Aerospace Engineering, Science and Research Branch
Mansour Nikkhah Bahrami۳ - Professor, Department of Mechanical Engineering, University of Tehran, Tehran

In this paper, torsional natural frequencies of a crank shaft based on analytical wave propagation method are presented. The wave propagation method for a continuous system which has eccentricity is expanded in this work. This method avoids the necessity of having to assume some hypothetical mode shapes which is vital but at the same time, a restriction in some well-known methods as Rayleigh-Ritz and Stodala methods. This method also gives the frequency characteristic equation, by which all the frequencies could be calculated. This method also avoids the trial and error method of Myklestad and Holzer method, as well.

Modified Wave Approach; Reflection, Propagation and Transmission Functions; Torsional Natural Frequencies; Mode Shapes; Crank Shaft