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The Dynamics of Rotor-Bearing Systems Using Finite Elements

705

Citations

0

References

1976

Year

TLDR

The study presents a procedure for dynamic modeling of rotor‑bearing systems comprising rigid disks, distributed‑parameter rotor elements, and discrete bearings. The authors develop a finite‑element model in both fixed and rotating frames, incorporating rotatory inertia, gyroscopic moments, axial load, and linear bearing stiffness and damping, and apply a coordinate‑reduction technique for variable cross‑section elements. The model predicts natural whirl speeds and unbalance responses for overhung rotor systems under two bearing parameter sets, and the results agree with an independent lumped‑mass analysis.

Abstract

A procedure is presented for dynamic modeling of rotor-bearing systems which consist of rigid disks, distributed parameter finite rotor elements, and discrete bearings. The formulation is presented in both a fixed and rotating frame of reference. A finite element model including the effects of rotatory inertia, gyroscopic moments, and axial load is developed using the consistent matrix approach. A reduction of coordinates procedure is utilized to model elements with variable cross-section properties. The bearings may be nonlinear, however, only the linear stiffness and viscous damping case is considered. The natural whirl speeds and unbalance response of a typical overhung system is presented for two sets of bearing parameters: (i) undamped isotropic, (ii) undamped orthotropic. A comparison of results is made with an independent lumped mass analysis.