Nonlinear secondary whirl of an overhung rotor

Nandakumar, Kutty Selva; Chatterjee, Anindya

doi:10.1098/rspa.2009.0262

Cited by 5 publications

(4 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The solutions to Eq. (25) can be expressed in a combination of forward and backward whirling motions. The solution of final form for first-order equations becomes:…”

Section: Formulation Of Dynamic Displacementmentioning

confidence: 99%

Nonlinear forced vibrations analysis of overhung rotors with unbalanced disk

2015

View full text Add to dashboard Cite

In this paper, primary resonances of a cantilever flexible shaft carrying a rigid disk at its free end (overhung rotor) are investigated. Unbalance forces due to eccentricity and disk skew are simultaneously considered, and the shaft has initially static deflection due to the rotor's weight which causes asymmetry in the equations of motion. The rotor has large amplitude vibrations, which lead to nonlinearities in curvature and inertia. In the model, rotary inertia and gyroscopic effects are included, but shear deformation is neglected. The method of multiple scales is applied to the discretize differential equations of motion. It is shown that the static deflection creates second-order nonlinear terms and near the primary resonances only the forward modes are excited. With considering the gravity, the inertial nonlinearities become stronger near the primary resonances. So, gravity decreases the hardening effect, and the nonlinear system tends to a linear system. It is concluded that the gravity effect has a softening effect. By using this property of gravity, a relation between weight and external forces is derived, in which by applying this relation the jumping phenomenon is eliminated. Numerical examples are presented, and the result is verified by numerical simulations.

show abstract

“…The solutions to Eq. (25) can be expressed in a combination of forward and backward whirling motions. The solution of final form for first-order equations becomes:…”

Section: Formulation Of Dynamic Displacementmentioning

confidence: 99%

Nonlinear forced vibrations analysis of overhung rotors with unbalanced disk

2015

View full text Add to dashboard Cite

show abstract

“…It should be noted here that in such situations the parallel misalignment of shafts connected in this way transforms into their angular misalignment. It usually occurs as a result of degradation of bearing supports in the (1) where: Θ(t) = t 0…”

Section: Modelling Of the Rotor-shaft Misalignmentsmentioning

confidence: 99%

“…Because of these reasons, the rotating machines with overhung rotors became an object of numerous dynamic investigations during the last decade. In [1], nonlinear whirl effects are studied for the overhung rotor model of Crandall and Brosens. In [2], a dynamic interaction of the unbalanced flexible overhung rotor with ball bearings is investigated.…”

Section: Introductionmentioning

confidence: 99%

Bulletin of the Polish Academy of Sciences: Technical Sciences

Szolc,

Konowrocki

2021

View full text Add to dashboard Cite

The rotating machines with overhung rotors form a broad class of devices used in many types of industry. For this kind of rotor machine in the paper, there is investigated an inf luence of dynamic and static unbalance of a rotor, parallel and angular misalignments of shafts, and inner anisotropy of rigid couplings on system dynamic responses. The considerations are performed through a hybrid structural model of the machine rotor-shaft system, consisting of continuous beam finite elements and discrete oscillators. Numerical calculations are carried out for parameters characterizing a heavy blower applied in the mining industry. The main goal of the research is to assess the sensitivity of the imperfections mentioned above on excitation severity of rotor-shaft lateral vibrations and motion stability of the machine in question.

show abstract

“…Nagasaka et al [16] did further research by studying internal resonance between the forward and backward whirl modes near both the primary and the secondary critical speeds for a simply-supported rotor system with asymmetric shaft. Based on above research, Nandakumar et al [17] extended their research to an overhung rotor with substantial gyroscopic effects and relatively large lateral vibration using the method of multiple scales (MMS). The authors derived the theoretical nonlinear equations of motion for an asymmetrical overhung rotor running near its gravity critical speed.…”

mentioning

confidence: 99%

A Full Spectrum Analysis Methodology Applied to an Anisotropic Overhung Rotor

Wu¹,

Naugle²,

Meagher³

2016

J Appl Mech Eng

View full text Add to dashboard Cite

This paper demonstrates the methodology and usefulness of full spectrum analysis on theoretical models and experimental measurements. This method establishes another bridge between model and data that is not currently being used to its greatest advantage. Some experimental devices display full spectrum vibration signals but most often half spectrum is reported. Correlating analytical models with experimental data using full spectrum analysis is similarly underutilized.In this paper, 3D full spectrum plots from x and y signals (from either experimental or theoretical results) are shown to match very well with the plots generated by experimental ADRE software. Tracking filters are used to isolate synchronous and non-synchronous vibration and allow for accurate phase angle measurement. The strategy developed by this paper can accurately convert the math angle from theoretical model to experimental instrumentation phase angle. Then we draw direct comparison of experimental results of a flexible overhung rotor with theoretical results to estimate unknown system parameters such as bearing stiffness and skew angle due to the gyroscopic effect. Finally, our paper provides other significant results such as 3D orbit plots. The tools developed here directly connect the experiment to the theoretical model and can be used to verify theoretical models with greater confidence.

show abstract

Nonlinear secondary whirl of an overhung rotor

Cited by 5 publications

References 23 publications

Nonlinear forced vibrations analysis of overhung rotors with unbalanced disk

Nonlinear forced vibrations analysis of overhung rotors with unbalanced disk

Bulletin of the Polish Academy of Sciences: Technical Sciences

A Full Spectrum Analysis Methodology Applied to an Anisotropic Overhung Rotor

Contact Info

Product

Resources

About