Stability Characteristics of Floating Bush Bearings

Tanaka, Masato; Hori, Yukio

doi:10.1115/1.3451700

Cited by 61 publications

(41 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The friction torque in the outer oil film retards the ring rotation. Further technical details on the working principle of full-floating ring bearings can be found in [31,37].…”

Section: Bearing Model (Fe Subsystem)mentioning

confidence: 99%

Coupled simulation of multibody and finite element systems: an efficient and robust semi-implicit coupling approach

Busch

Schweizer

2011

Arch Appl Mech

View full text Add to dashboard Cite

Standard coupling approaches for simulating coupled MBS/FEM systems may entail enormous CPU times in order to achieve a stable and accurate solution. To stabilize and speed up the solution process, semi-implicit coupling approaches can be applied successfully. In literature, semi-implicit coupling approaches have been introduced, where Jacobian information is exchanged between the subsystems using partial derivatives with respect to the state vectors of the subsystems. The drawback of these methods is that the numerical calculation of the Jacobians with respect to the whole state vector of the subsystems is very time-consuming.The key idea of the semi-implicit coupling technique presented here is to reduce the computational effort by using Jacobian information only with respect to the coupling variables.The semi-implicit coupling technique introduced here is exemplarily applied for coupling a commercial MBS code with a commercial FEM code. As a practical example, we consider a hybrid nonlinear rotor/bearing model of a high-speed turbine. The rotor is modeled as a flexible multibody system. For calculating the bearing reactions, a finite element discretization of Reynolds fluid film equation is applied which yields the pressure distribution in the fluid films of the hydrodynamic bearings. Both codes are coupled via interprocess communication (IPC). A very time-efficient implementation of the semi-implicit coupling approach can be accomplished by a parallelization on multiple CPUs.

show abstract

“…The friction torque in the outer oil film retards the ring rotation. Further technical details on the working principle of full-floating ring bearings can be found in [31,37].…”

Section: Bearing Model (Fe Subsystem)mentioning

confidence: 99%

Coupled simulation of multibody and finite element systems: an efficient and robust semi-implicit coupling approach

Busch

Schweizer

2011

Arch Appl Mech

View full text Add to dashboard Cite

show abstract

“…Tanaka and Hori [10], for instance, formulated an analytical model of a floating ring bearing and carried out a stability analysis about the equilibrium of the centered position by means of linearization and application of the Routh-Hurwitz criterion.…”

Section: Introductionmentioning

confidence: 99%

Analytical bifurcation analysis of a rotor supported by floating ring bearings

et al. 2008

View full text Add to dashboard Cite

Like with other types of fluid bearings, rotors supported by floating ring bearings may become unstable with increasing speed of rotation due to selfexcited vibrations. In order to study the effects of the nonlinear bearing forces, within this contribution a perfectly balanced symmetric rotor is considered which is supported by two identical floating ring bearings. Here, the bearing forces are modeled by applying the short bearing theory for both fluid films. A linear stability analysis about the static equilibrium position of the rotor shows that for a critical revolution speed the real part of an eigenvalue pair changes its sign. By means of a center manifold reduction it is shown that this destabilization of the steady state is due to a Hopf-bifurcation. Furthermore, the type of this bifurcation is determined as well as the existence and stability of limit-cycles. Notably it is found that depending on the parameters of the floating ring bearing subcritical as well as supercritical bifurcations may occur. Additionally, the analytical results obtained from the center manifold reduction are compared to numerical results by a continuation method. In conclusion, the influences of bearing design parameters on the stability and on the limit-cycles are discussed.

show abstract

“…Experimental investigations on self-excited vibrations of rotors in floating ring bearings are reported in [27], where also the stabilization of the rotor at higher rotor speeds has been observed. Analytical stability investigations for a Laval rotor in full-floating ring bearings based on a linear stability analysis have been performed in [28][29][30]. Experimental investigations on the ring-to-shaft speed ratio have, for instance, been carried out in [31,32].…”

Section: Introductionmentioning

confidence: 99%

Oil whirl, oil whip and whirl/whip synchronization occurring in rotor systems with full-floating ring bearings

Schweizer

2009

Nonlinear Dyn

View full text Add to dashboard Cite

High-speed rotors are often supported in floating ring bearings because of their good damping behavior. In contrast to conventional hydrodynamic bearings with a single oil film, full-floating ring bearings consist of two oil films: An inner and an outer oil film. As single oil-film bearings, full-floating ring bearings also show the typical fluid-film-induced instabilities (self-excited vibrations). Both inner and outer oil films can become unstable and exhibit oil whirl/whip instabilities.The paper at hand considers a Laval (Jeffcott) rotor, which is symmetrically supported in full-floating ring bearings, and investigates the occurring oil whirl/whip effects by means of run-up simulations. It is shown that the inner oil film, which usually becomes unstable first, gives rise to a limit-cycle oscillation with an exactly circular rotor orbit, if gravity and imbalance are neglected. Interesting is the instability generated by the outer oil film. The calculations demonstrate that instability in the outer oil film does not lead to a simple circular limit-cycle orbit. Whirl/whip-induced limit-cycle oscillations generated by the outer oil film are more complex and entail a coupled circumferential and radial motion, although the mechanical problem B. Schweizer ( )

show abstract

Stability Characteristics of Floating Bush Bearings

Cited by 61 publications

References 0 publications

Coupled simulation of multibody and finite element systems: an efficient and robust semi-implicit coupling approach

Coupled simulation of multibody and finite element systems: an efficient and robust semi-implicit coupling approach

Analytical bifurcation analysis of a rotor supported by floating ring bearings

Oil whirl, oil whip and whirl/whip synchronization occurring in rotor systems with full-floating ring bearings

Contact Info

Product

Resources

About