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Characteristics of the nonlinear hysteresis loop for rotor-bearing instability

Guo, Jenq-Shan
http://rave.ohiolink.edu/etdc/view?acc_num=case1062688989

Abstract Details

1995, Doctor of Philosophy, Case Western Reserve University, Mechanical Engineering.
The nonlinear hysteresis loop of a simple-cylindrical-journal-bearing supported rotordynamic system is characterized by the Hopf-bifurcation and Saddle-Node bifurcation speeds. The nonlinearity of this system occurs in the journal-bearing fluid-film forces, and requires the imbedding of a solution for the Reynolds lubrication education within a numerical integration scheme of the coupled motion equations in order to perform proper simulations. These show that under a light bearing static load, the Saddle-Node and Hopf bifurcations coalesce to a single speed at essentially two times the self-excited vibration frequency (i.e., the lowest natural frequency) At higher bearing loads, the classical instability threshold speed (i.e., Hopf bifurcation) occurs at progressively higher rotor speeds. However, the disappearance speed (Saddle Node of the periodic orbit) of the nonlinear limit cycle occurs at progressively lower rotor speeds, asymptotically approaching approximately 1.725 times the lowest natural frequency. By adding a rotor unbalance force to the model, exploratory simulations have been made to determine the extent to which chaos signal processing in the normal speed-up or coast-down vibration of actual machines could be used to locate this lower speed bound of the instability hysteresis loop. Laboratory experiments were performed and these agree quite well with simuiation results
M. Adams (Advisor)
179 p.
Engineering, Aerospace
Nonlinear hysteresis loop; Instability threshold speed; Rotor-bearing instability

Recommended Citations

Citations

  • Guo, J.-S. (1995). Characteristics of the nonlinear hysteresis loop for rotor-bearing instability [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1062688989

    APA Style (7th edition)

  • Guo, Jenq-Shan. Characteristics of the nonlinear hysteresis loop for rotor-bearing instability. 1995. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1062688989.

    MLA Style (8th edition)

  • Guo, Jenq-Shan. "Characteristics of the nonlinear hysteresis loop for rotor-bearing instability." Doctoral dissertation, Case Western Reserve University, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=case1062688989

    Chicago Manual of Style (17th edition)

case1062688989
1,065
© 1995, all rights reserved.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.