This paper describes an active control method to prevent unwanted nonlinear vibration response modes of a rotordynamic system. Nonlinear stiffness of components that support or surround a machine rotor can cause a response branch that extends critical vibration (resonance) over a wide interval of rotational speeds. Within this interval, jump transitions between alternative low amplitude and hig...

In machine systems where a rotor spins within a finite clearance space supported by bearings, contact between the rotor and its surround can result in persistent coupled vibration of the rotor and stator. When the vibration response is driven predominantly by friction forces, rotordynamic stability becomes a serious issue. This paper introduces a theory for model-based verification of dynamic s...

A 2005 TRC report presents imbalance response measurements of a hollow test rotor supported on bump-type gas foil bearings. The top speed of the tests is 25 krpm, the limit of the drive router motor. The 2005 measurements show the gas foil bearings are prone to subsynchronous whirl with amplitudes of motion exacerbated by the imbalance condition of the rotor, i.e. a forced nonlinearity. Present...

Abstract In this paper, we study experimentally the fluid-structure interaction of a simplified small-scale rotor operating in water channel. The consists single untwisted rectangular blade and is tested with various pitch angles at different rotation speeds free stream velocities. Flapwise deformations are measured using image processing, flow fields obtained by Particle Image Velocimetry. exh...

In this study, a moderately flexible rotor is investigated experimentally in water channel. The consists of single blade with simplified rectangular geometry and tested various pitch angles at different rotational speeds. flapwise bending deformation induced torsion the are measured using image processing tools, flow fields extracted Particle Image Velocimetry. behaviour depends strongly on ang...

The optimum design of a flexible rotor supported on three-lobe bearings, overhung centrifugal compressor, is studied for the optimal unbalance response using the genetic algorithm (GA) and method of feasible directions (MFD). The MFD is used to verify the GA results. The feasibility, effectivness, and avaliability of the GA is certainly of value because it allows the exploration of many differe...