Abstract
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.
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References
Li, C., Yu, H., Zhou, S., Wen, B.: Simulations and experimental investigation on motion stability of a flexible rotor-bearing system with a transverse crack. Chinese Journal of Mechanical Engineering 26(6), 1194–1203 (2013).
Huang, Z.: Dynamic analysis of a rotor-bearing system with coupling faults of crack and rub-impact. In Journal of Physics: Conference Series, vol. 744(1), p. 012158. IOP Publishing (2016).
Sharafi, M., Nikravesh, M., Safarpour, P.: Analytical approach to calculate bending, longi-tudinal and torsional local stiffness of an asymmetric circumferential crack with contact condition. Mechanical Systems and Signal Processing, 94, 448–463 (2017).
Han, Q., & Chu, F.: Parametric instability of a rotor-bearing system with two breathing transverse cracks. European Journal of Mechanics-A/Solids, 36, 180–190 (2012).
Han, Q., & Chu, F.: Parametric instability of a Jeffcott rotor with rotationally asymmetric inertia and transverse crack. Nonlinear Dynamics 73(1-2), 827–842 (2013).
Peng, H., He, Q., Zhen, Y.: Stability analysis of a breathing cracked rotor with imposed mass eccentricity. Shock and Vibration, (2015).
Chauvin Jr, D.: An Experimental Investigation of Whirl Instability Including Effects of Lub-ricant Temperature in Plain Circular Journal Bearings. Louisiana State University Agricul-tural and Mechanical College (2003).
Ignacio R., Luis M., Humberto C.: Vibrational Response of a Rotor Supported in Hydrody-namics Short Bearings. Memories Del Xix International Congress of Her Annual Somim, 25-27 September, pp. 1085-1094. PACHUCA, HIDALGO, MEXICO (2013).
Abed S., Al Drajy J., Bahrami M.: Numerical investigation of a rotary-bearing system with a single crack using harmonic analysis. St. Petersburg Polytechnic university journal of en-gineering science and technology, 24(03), 139–152 (2018).
Rao, X., Chu, Y., Chang, Y., Zhang, J., Tian, Y.: Dynamics of a cracked rotor system with oil-film force in parameter space. Nonlinear Dynamics, 88(4), 2347–2357 (2017).
Friswell, M., Penny, J., Garvey, S., Lees, A.: Dynamics of Rotating Machines. Cambridge University Press, 32 Avenue of the Americas New York NY 10013 (2010).
Penny, J., Friswell M.: The Dynamics of Cracked Rotors. IMAC-XXV: A Conference & Exposition on Structural Dynamics, Orlando, FL, February 19-22, 2007, Society for Exper-imental Mechanics, Bethel, CT, paper198 (2007).
Nagaraju T., Srinivas K.: Rotor Dynamic Analysis of Steam Turbine Rotor Using ANSYS. International Journal of Mechanical Engineering and Robotics Research (IJMERR), 3(1), 338–349 (2014).
Abed S., Bahrami M., Thijel J.: Analytical and Numerical Investigation to the Effect of Two Cracks on the Dynamic Behavior of Rotor-Bearings System. Russian scientific journal Sci-ence and Business: ways of development, 11(89), (2018).
Abed S., Bahrami M., Thijel J.: Dynamic Behavior of Rotor-Bearings System with Chang-ing Angle Orientation between Two Cracks. Russian scientific journal Science Prospects, 11(110), (2018).
Rao J.S.: History of Rotating Machinery Dynamics. Springer Science + Business Media B.V. (2011).
Athanasios, C.: Vibration Analysis of Nonlinear-Dynamic Rotor-Bearing Systems and De-fect Detection. Mechanical Engineering and Aeronautics, University of Patras (2009)
Untaroiu, C., Untaroiu, A., Boiangiu, M.: Dynamic Stability Analysis of Periodically Time-Varying Rotor System with a Transverse Crack. Engineering, 3(07), 719–725 (2011).
Luneno, J.: Cases of Coupled Vibrations and Parametric Instability in Rotating Machines. Department of Engineering Sciences and Mathematics Division of Mechanics of Solid Me-chanics, Lulea University of Technology, SE-97187 Sweden (2012).
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Ahmed, A.S., Reza, B.M., Farij, T.J. (2019). Stability of a Flexible Rotor-Bearing System with a Transverse Crack. In: Uhl, T. (eds) Advances in Mechanism and Machine Science. IFToMM WC 2019. Mechanisms and Machine Science, vol 73. Springer, Cham. https://doi.org/10.1007/978-3-030-20131-9_332
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DOI: https://doi.org/10.1007/978-3-030-20131-9_332
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