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1

Exploiting gyroscopic effects for resonance elimination of an elastic rotor utilizing only one piezo actuator

Jungblut Jens, Franz Daniel, Fischer Christian, Rinderknecht Stephan

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2023

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Vol. 71, nr 6

art. no. e147060

EN

A gyroscopic rotor exposed to unbalance and internal damping is controlled with an active piezoelectrical bearing in this paper. The used rotor test-rig is modelled using an FEM approach. The present gyroscopic effects are then used to derive a control strategy which only requires a single piezo actuator, while regular active piezoelectric bearings require two. Using only one actuator generates an excitation which contains an equal amount of forward and backward whirl vibrations. Both parts are differently amplified by the rotor system due to gyroscopic effects, which cause speed-dependent different eigenfrequencies for forward and backward whirl resonances. This facilitates eliminating resonances and stabilize the rotor system with only one actuator but requires two sensors. The control approach is validated with experiments on a rotor test-rig and compared to a control which uses both actuators.

2

Vibration analysis of functionally graded tapered rotor shaft system

Elhannani Abdelhak, Refassi Kaddour, Elmeiche Abbes, Bouamama Mohamed

Mechanics and Mechanical Engineering

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2019

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Vol. 23, nr 1

241--245

EN

This investigation deals with the vibration analysis of a rotating tapered shaft in Functionally Graded Material (FGM). The dynamic system is modeled using the Timoshenko beam theory (FSDBT) with consideration of gyroscopic effect and rotary inertia. The equations of motion are expressed by the hierarchical finite element method based on bi-articulated boundary conditions. The material properties are continuously varied in the thickness direction of a hollow shaft according to the exponential law function (E-FGM). The presented model is validated by comparing the numerical results found with the available literature. Various analyses are carried out to determine the influence of taper angle and material distribution of the two extreme materials on the dynamic behavior of FGM conical rotors system.

3

Experimental identification of rotating and stationary damping in a cracked rotor system with an offset disc

Roy Dipendra K., Tiwari Rajiv

Archive of Mechanical Engineering

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2019

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Vol. LXVI, nr 4

447--474

EN

In the rotor system, depending upon the ratio of rotating (internal) damping and stationary (external) damping, above the critical speed may develop instability regions. The crack adds to the rotating damping due to the rubbing action between two faces of a breathing crack. Therefore, there is a need to estimate the rotating damping and other system parameters based on experimental investigation. This paper deals with a physical model based an experimental identification of the rotating and stationary damping, unbalance, and crack additive stiffness in a cracked rotor system. The model of the breathing crack is considered as of a switching force function, which gives an excitation in multiple harmonics and leads to rotor whirls in the forward and backward directions. According to the rotor system model considered, equations of motion have been derived, and it is converted into the frequency domain for developing the estimation equation. To validate the methodology in an experimental setup, the measured time domain responses are converted into frequency domain and are utilized in the developed identification algorithm to estimate the rotor parameters. The identified parameters through the experimental data are used in the analytical rotor model to generate responses and to compare them with experimental responses.

4

Development of identification procedure for the internal and external damping in a cracked rotor system undergoing forward and backward whirls

Roy Dipendra Kumar, Tiwari Rajiv

Archive of Mechanical Engineering

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2019

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Vol. LXVI, nr 2

229--255

EN

In the present work, a procedure for the estimation of internal damping in a cracked rotor system is described. The internal (or rotating) damping is one of the important rotor system parameters and it contributes to the instability of the system above its critical speed. A rotor with a crack during fatigue loading has rubbing action between the two crack faces, which contributes to the internal damping. Hence, internal damping estimation also can be an indicator of the presence of a crack. A cracked rotor system with an offset disc, which incorporates the rotary and translatory of inertia and gyroscopic effect of the disc is considered. The transverse crack is modeled based on the switching crack assumption, which gives multiple harmonics excitation to the rotor system. Moreover, due to the crack asymmetry, the multiple harmonic excitations leads to the forward and backward whirls in the rotor orbit. Based on equations of motions derived in the frequency domain (full spectrum), an estimation procedure is evolved to identify the internal and external damping, the additive crack stiffness and unbalance in the rotor system. Numerically, the identification procedure is tested using noisy responses and bias errors in system parameters.

5

Impact analysis of gyroscopic effects on motorcycle’s stability

Grzegożek W., Weigel-Milleret K.

Logistyka

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2015

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nr 4

3556--3562, CD2

EN

Stability, which is one of the more important properties of single-track vehicles, defined as its resistance to interference or disturbance and returning the motorbike to ride straight ahead after riding in a turn depends on many factors. The influence of gyroscopic effects of the motorcycle on its stability was analyzed on a specially designed drum bench stand. The role of the gyroscopic effect in motorbike designs is significant. The study included wobble vibrations for different speeds and different angles of the front fork of the motorcycle, with and without the gyroscopic effect. The paper contains a description of the issues of vibration occurring in single-track vehicles, description of the bench test and compilation of the results.

PL

Stateczność, stabilność (ang. stability) motocykla, będąca jedną z ważniejszych właściwości pojazdów, rozumianą jako jego odporność na działanie zakłóceń czy zaburzeń w czasie ruchu prostoliniowego, powrotu do jazdy na wprost po wystąpieniu takiego zaburzenia a także wystąpienia niepożądanych form ruchu, zależy od wielu czynników. Podjęto próbę wykonania badań wpływu efektów żyroskopowych motocykla na jego stabilność na specjalnie skonstruowanym bębnowym stanowisku badawczym. Wpływ efektów żyroskopowych nie może być pomijany w rozważaniach o stabilności. Badaniami objęto drgania typu wobble dla różnych prędkości i różnych kątów pochylenia przedniego widelca motocykla z i bez efektu żyroskopowego. Praca zawiera opis zagadnień drganiowych występujących w pojazdach jednośladowych, opis wykonanego stanowiska badawczego a także metodykę i sposób przeprowadzenia badań oraz opis opracowanych wyników.

6

Dynamics of the air blower with gyroscopic couple

Vasylius M., Augustaitis V., Barzdaitis V., Bogdevicius M.

Acta Mechanica et Automatica

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2008

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Vol. 2, no. 3

95-98

EN

To avoid damaging of tilting pad journal bearings, the problem of safety shut down of high speed air blower cantilever rotor becoming important in modern industry. The experimental testing, modeling and simulation of dynamic behavior of rotating system was run to directly evaluate gyroscopic negative effect damaging journal bearings. A dynamic model of air blower rotating system was designed and simulated. A simulation and experimental measurement results of rotating system were used to optimize the shut down regime of machine. Gyroscopic effect influences of rotor bearing stability are confirmed. Results of numerical simulation confirm results of experimental vibration measuring. The theoretical research results are given and conclusions are made. Experimental testing and simulations results was applied to typical air blower rotating systems for elimination of huge negative forces acting on new bearings during shut down of the machine.

7

Stability of Composite Rotors with Massive Discs and Follower Load

Weronko J., Kurnik W.

Machine Dynamics Problems

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2006

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Vol. 30, No. 1

113-124

EN

The paper is concerned with a new approach to the stability behaviour of a rotating composite shaft with two supports and massive disc at the end using dynamic eigenvalues and eigenform for bifurcation analysis. The shaft subjected to tip-concentrated axial follower load and discussion is focused on the influence of gyroscopic effect on the critical rotation speed and post-critical behaviour of the system. Dynamic base functions are applied in Galerkin's discretization procedure. Two mechanisms of flutter instability exhibited by the system are studied and explained for prospective applications in industrial machinery like compressors, pumps and turbines.

8

Numerical analysis of vertical rotor dynamics of ACWW 1000 centrifuge

Zachwieja J., Ligier K.

Journal of Theoretical and Applied Mechanics

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2005

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Vol. 43 nr 2

256--275

EN

In this work, a numerical approach to analysis of dynamics of a hung rotor has been presented. A vertical rotor of the ACWW\,1000 centrifuge has been used as a real object for verification of the discussed model. This rotor, due to its constructional features, should show the gyroscopic effect in the range of achievable rotational speed.

PL

W pracy przedstawiona została analiza dynamiki wirnika przewieszonego w ujęciu numerycznym. Obiektem rzeczywistym, który posłużył do weryfikacji zastosowanego modelu, był pionowy wirnik wirówki ACWW 1000, który z uwagi na cechy konstrukcyjne powinien wskazywać podatność na wpływ efektów żyroskopowych.

9

Gyroscopic Effect in the Stability Problem of a Slender Rotating Shaft with Follower Load

Kurnik W., Przybyłowicz P. M., Weronko J., Wiatr P.

Machine Dynamics Problems

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2003

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Vol. 27, No. 2

55-70

EN

The paper is concerned with stability analysis of a flexible rotating shaft supported as a cantilever beam and subjected to tip-concentrated follower load. Such systems exhibit two mechanisms of instability of flutter type, different in physical nature and, what is most important, interacting to produce complicated stability regions in the space of rotation speed and follower load. In such systems even for high-speed working conditions, the rotary inertia as well as the gyroscopic effect is usually neglected like in slender beams. However, in some regions of parameters, especially in slightly internally dissipative shafts the gyroscopic effect can considerably change the boundaries of the stability domain. Moreover, an interesting phenomenon can be observed when two pairs of eigenvalues with different speeds at the same time intersect the imaginary axis of the complex plane. This leads to bifurcation with four critical eigenvalues similar to that studied by Iooss in the Navier-Stokes equations.

10

Efekt żyroskopowy w dynamice walców maszyny papierniczej

Zachwieja J.

Zeszyty Naukowe. Mechanika / Akademia Techniczno-Rolnicza w Bydgoszczy

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2002

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Z. 53(241)

311-323

PL

Praca zawiera analizę wpływu efektu żyroskopowego na wartość prędkości krytycznej walca prowadzącego wstęgę papieru w krajarce KL63. Wykazano, że stosunkowo duża jego sztywność wpływ ten znacząco ogranicza. W identyczny sposób oddziałuje wzrost podatności podparcia walca.

EN

The work contains an analysis of gyroscopic effect influence on a critical speed value of cylinder that leads a band of paper in a KL63 cutter. It was proved that its relatively high stiffness limits this influence very much. The same effect is achieved by an increase of flexibility of cylinder support.