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Dino Bousso (1933-1971)
● TITLE: A stability criterion for rotating shafts
● AUTHOR: Bousso, D.
● SOURCE: Israel Journal of Technology, v. 10, pp. 409-423 (1972).
● LANGUAGE: English.
● ABSTRACT: The stability of an inertia mounted on a rotating flexible shaft is dealt with by means of a perturbation method. In contrast to the Routh-Hurvitz stability criterion for which linearization of the equations of motion is required, this method is based on direct analysis of forces and moments acting on the inertia when it precesses at any of its natural frequencies as a result of a random disturbance. A realistic non-linear friction law is assumed in setting up the stability criterion. The influence of load moment, hitherto neglected in stability considerations, is explained. The method used is based on a physical approach to the problem and leads to a deeper understanding of the stability problems through its direct analysis of the operating forces.

● REVIEW SOURCE: Applied Mechanics Reviews, v. 27, p. 1536, No. 9265 (1974)
● FIRST REVIEW: An interesting and simple approach to the stability analysis of rotor motion is presented. The method is not based on the mathematical theory of stability of motion but on physical considerations using simple models. The effect of inertial friction and load moment is analyzed. The latter represents the most important contribution of the author. He proves in some examples that the methods using linearized acting forces sometimes fail to explain phenomena, or if they do not, there may be qualitative differences between nonlinear and linear approach. This is in agreement with some results of recent papers which are not mentioned in the references. The paper contains interesting and stimulating ideas especially for designers of rotating machines and researchers in rotor dynamics.

● SECOND REVIEWERS: R. Cohen, I. Porat (1934-2012)
● SECOND REVIEW SOURCE: "Influence of load torque on stability of rotor driven by flexible shaft,"
Journal of Sound and Vibrations, v. 95, pp. 151-160 (1984). See pp. 151, 159.
● SECOND REVIEW: Bousso, investigating the case of an overhung rotor driven by a flexible shaft, attributed the destabilizing effect of the load torque to the angular deviation between the latter and the external torque as the shaft is deformed. He also established a qualitative stability criterion as a function of the ratio of the external and internal damping, the precession role and load torque. His work indicated that the load torque tends to excite the forward precession while attenuating the backward precession.

● COMMENT: This paper was submitted for publication by Bousso's supervisor in this research, Boaz Popper (1927-2012), after Bousso passed away in 1971.
Ben-Amots, Netsivi., "The motion of a high-speed rotor under the influence of a moment perpendicular to the axes of precession and nutation," D.Sc. thesis, Technion, Haifa, Israel (1975). Supervisors: Bousso, Dino (1933-1971), and Porat, Itzhak (1934-2012). (HEBREW with English synopsis). Abstract in English Abstract in Hebrew

Vance, J.M., "Torquewhirl theory to explain nonsynchronous whirling failures of rotors with high-load torque," J. Eng. Power Trans. ASME, v. 100, No. 2, pp. 235-240 (1978).

Nonami, K, Miyashita, M., "Problem of rotor passing through critical speed with gyroscopic effect 2. (Generating of self-exited vibration caused by internal damping)," Bull. JSME-Japan Soc. Mech. Eng. v. 22, No. 169, pp. 911-918 (1979).

4. Shen, Shan Fu, and Mengle, Vinod G., "Non-synchronous whirling due to fluid-dynamics forces in axial turbo- machinery rotors," ASME Winter Annual Meeting, New-York (1977) pp. 75-87. Also pp. 267-284 in: "Instability problems in high performance turbomachinery," NASA (1980).

Vance, J.M., Torque - whirl A theory to explain non - synchronous whirling failures of rotors with high speed, pp. ?-279 in: Rotordynamic Instability Problems in High-performance Turbomachinery, National Aeronautics and Space Administration, Scientific and Technical Information Branch, - Impellers (1980)

Cohen, R., "Effect of the coupling between flexural and torsional vibrations on rotors driven by a flexible shaft," D.Sc. thesis, Technion, Haifa, Israel (1982), p. 11, 203. (HEBREW with English abstract). Abstract in English Abstract in Hebrew

Cohen, R., I. Porat (1934-2012) "Influence of load torque on stability of rotor driven by flexible shaft," J. Sound Vib., v. 95, pp. 151-160 (1984).

Yim, K.B., Noah, S.T., Vance, J.M., "Effect of tangential torque on the dynamics of flexible rotors," J. Appl. Mech. Trans. ASME, v. 53, No. 3, pp. 711-718 (September 1986).

Vance, J.M., "Rotordynamics of turbomachinary," Wiley, New Jersey (1988) p. 316

Choi, Myungjin, Dynamics and vibrations of high-speed rotor bearing systems containing cam shafts and crankshafts, Ph.D. thesis, North Carolina State University, (1992)

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