Stability of a Flexible Rotor-Bearing System with a Transverse Crack

  • Abed Salam Ahmed
  • Bahrami Mohammad RezaEmail author
  • Thijel Jassim Farij
Conference paper
Part of the Mechanisms and Machine Science book series (Mechan. Machine Science, volume 73)


The aim of this paper is to analyze the stability of a Jeffcott rotor with an offset disk rotor system with a crack. The theory of fracture mechanics has been used to simulate a Jeffcott model for rotor shafts with crack with changing the crack depths. The eccentricity ratio has been found from the modified Sommerfeld number with the help of the iteration method using the computer program of MATLAB. The effect of changing speeds on the dynamic parameters of journal bearings (stiffness and damping) and its effect on Sommerfeld number has been investigated. The relation between threshold speed and the Sommerfeld number has been gained. The results have been obtained analytically using MATLAB. The results show that the crack depth up to 0.8R has no effect on the stability. If the crack depth reaches to R-value the unstable region has high increasing while the stable zoon will decrease when the flexibility reduced 40% which will effect on the stability of rotors.


Rotor Dynamics Stability of Cracked Rotor Transverse Crack Theory of Fracture Mechanics 


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© Springer Nature Switzerland AG 2019

Authors and Affiliations

  1. 1.Peter the Great St.Petersburg Polytechnic UniversitySt. PetersburgRussia
  2. 2.Innopolis UniversityInnopolisRussia
  3. 3.Midland Refineries Company (Al - Daura Refinery) Ministry of OilBaghdadIraq

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