ross.MisalignmentFlex

class ross.MisalignmentFlex(rotor, n, mis_type, mis_distance_x, mis_distance_y, mis_angle, radial_stiffness, bending_stiffness, input_torque=0, load_torque=0)

Model misalignment on a given flexible coupling element of a rotor system.

Calculates the dynamic reaction force of hexangular flexible coupling induced by rotor misalignment of some kind based on [Xia et al., 2019].

Parameters:

rotorross.Rotor

Rotor object.

nfloat

Number of shaft element where the misalignment is ocurring.

mis_type: string

Name of the chosen misalignment type. The available types are: “parallel”, “angular” and “combined”.

mis_distance_xfloat, pint.Quantity

Parallel misalignment distance between driving rotor and driven rotor along X direction.

mis_distance_yfloat, pint.Quantity

Parallel misalignment distance between driving rotor and driven rotor along Y direction.

mis_anglefloat, pint.Quantity

Angular misalignment angle.

radial_stiffnessfloat, pint.Quantity

Radial stiffness of flexible coupling.

bending_stiffnessfloat, pint.Quantity

Bending stiffness of flexible coupling. Provide if mis_type is “angular” or “combined”.

input_torquefloat, pint.Quantity

Driving torque. Default is 0.

load_torquefloat, pint.Quantity

Driven torque. Default is 0.

Attributes:

shaft_elemross.ShaftElement

A 6 degrees of freedom shaft element object where misalignment is ocurring.

forcesnp.ndarray

Force matrix due to misalignment. Each row corresponds to a dof and each column to a time.

Returns:

A MisalignmentFlex object.

References

[AHR02]

KM Al-Hussain and I Redmond. Dynamic response of two rotors connected by rigid mechanical coupling with parallel misalignment. Journal of Sound and vibration, 249(3):483–498, 2002. doi:https://doi.org/10.1006/jsvi.2001.3866.

[Bar18]

Jefferson Silva Barbosa. Determinação da posição de equilíbrio em mancais hidrodinâmicos cilíndricos usando o algoritmo de evolução diferencial. REVISTA CEREUS, 2018.

[Cun25]

Bárbara N. T. Cunha. Método do Balanceamento Harmônico aplicado na solução das equações do movimento de máquinas rotativas com efeitos dinâmicos não-lineares. PhD Thesis, Universidade Federal de Uberlândia, Uberlândia, MG, 2025.

[Dan12]

G Daniel. Desenvolvimento de um modelo termodinâmico para análise em mancais segmentados. Universidade Estadual de Campinas, 2012.

[DC13]

Gustavo Barbosa Daniel and Katia Lucchesi Cavalca. Evaluation of the thermal effects in tilting pad bearing. International Journal of Rotating Machinery, 2013:725268, 2013. doi:10.1155/2013/725268.

[DSRG20]

Mohamed Desouki, Sadok Sassi, Jamil Renno, and Samer Gowid. Dynamic response of a rotating assembly under the coupled effects of misalignment and imbalance. Shock and Vibration, 2020:1–26, 10 2020. doi:10.1155/2020/8819676.

[FN92]

M. K. Fitzgerald and P. B. Neal. Temperature distributions and heat transfer in journal bearings. Journal of Tribology, 114(1):122–130, 1992. doi:10.1115/1.2920860.

[Fri10]

Michael I Friswell. Dynamics of rotating machines. Cambridge University Press, 2010.

[Gas93]

R Gasch. A survey of the dynamic behaviour of a simple rotating shaft with a transverse crack. Journal of sound and vibration, 160(2):313–332, 1993.

[GG88]

Giancarlo Genta and Antonio Gugliotta. A conical element for finite element rotor dynamics. Journal of Sound and Vibration, 120:175–182, 01 1988. doi:10.1016/0022-460X(88)90342-2.

[HSF07]

Niels Heinrichson, Ilmar Ferreira Santos, and Axel Fuerst. The influence of injection pockets on the performance of tilting-pad thrust bearings—part i: theory. Journal of Tribology, 129(4):895–903, 06 2007. URL: https://doi.org/10.1115/1.2768609, arXiv:https://asmedigitalcollection.asme.org/tribology/article-pdf/129/4/895/5824595/895_1.pdf, doi:10.1115/1.2768609.

[IY13]

Yukio Ishida and Toshio Yamamoto. Linear And Nonlinear Rotordynamics: a modern treatment with applications. John Wiley & Sons, 2013.

[KDA+13]

Jason Kaplan, sa Dousti, Paul Allaire, Bradley Nichols, Timothy Dimond, and Alexandrina Untaroiu. Rotor dynamic modeling of gears and geared systems. Proceedings of the ASME Turbo Expo, 7:, 06 2013. doi:10.1115/GT2013-94654.

[LT78]

JW Lund and KK Thomsen. A calculation method and data for the dynamic coefficients of oil-lubricated journal bearings. Topics in fluid film bearing and rotor bearing system design and optimization, 1978.

[MD84]

IW Mayes and WGR Davies. Analysis of the response of a multi-rotor-bearing system containing a transverse crack in a rotor. Journal of Vibration, Acoustics, Stress, and Reliability in Design, 106(1):139–145, 1984.

[Mot20]

Júlia de Araújo Mota. Estudo da teoria de lubrificação com parametrização diferenciada da geometria e aplicações em mancais hidrodinâmicos. Master's thesis, PPGI - Universidade Federal do Rio de Janeiro, 2020.

[Nic99]

R Nicoletti. Efeitos térmicos em mancais segmentados híbridos—teoria e experimento. Thermal Effects in Hybrid Tilting-Pad Bearings—Theory and Experiment), M. Sc. dissertation, Universidade Estadual de Campinas, Campinas, http://libdigi. unicamp. br/document, 1999.

[RSC98]

JS Rao, TN Shiau, and JR Chang. Theoretical analysis of lateral response due to torsional excitation of geared rotors. Mechanism and Machine Theory, 33(6):761–783, 1998. doi:https://doi.org/10.1016/S0094-114X(97)00056-6.

[Riu88]

José Antonio Riul. Estudo teórico e experimental de mancais hidrodinâmicos cilíndricos. Master's thesis, Universidade Federal de Uberlândia, 1988.

[RK80]

K. E. Rouch and J. S. Kao. Dynamic reduction in rotor dynamics by the finite element method. Journal of Mechanical Design, 102(2):360–368, 1980. doi:10.1115/1.3254752.

[XPY+19]

Yuanfeng Xia, Jian Pang, Liang Yang, Qin Zhao, and Xianwu Yang. Study on vibration response and orbits of misaligned rigid rotors connected by hexangular flexible coupling. Applied Acoustics, 155:286–296, 2019. doi:https://doi.org/10.1016/j.apacoust.2019.05.022.

[YIK02]

T Yamamoto, Y Ishida, and RG Kirk. Linear and nonlinear rotordynamics: a modern treatment with applications. Applied Mechanics Reviews, 55(3):B45–B46, 06 2002. doi:https://doi.org/10.1115/1.1470671.

[YLJP19]

Shuai Yang, Chun Li, Ming Jiang, and Shuai Pei. A study of inlet temperature models of a large size tilting thrust bearing: comparison between theory and experiment. Tribology International, 140:105881, 2019. doi:10.1016/j.triboint.2019.105881.

[YWWD16]

Yi Yang, Jiaying Wang, Xurong Wang, and Yiping Dai. A general method to predict unbalance responses of geared rotor systems. Journal of Sound and Vibration, 381:246–263, 2016. doi:https://doi.org/10.1016/j.jsv.2016.06.031.

Filter:

docname in docnames

Examples

>>> rotor = rs.rotor_example_with_damping()
>>> fault = MisalignmentFlex(
...     rotor,
...     n=0,
...     mis_type="combined",
...     mis_distance_x=2e-4,
...     mis_distance_y=2e-4,
...     mis_angle=5 * np.pi / 180,
...     radial_stiffness=40e3,
...     bending_stiffness=38e3,
...     input_torque=0,
...     load_torque=0
... )
>>> fault.shaft_elem
ShaftElement(L=0.025, idl=0.0, idr=0.0, odl=0.019,  odr=0.019, material='Steel', n=0)

Methods

__init__(rotor, n, mis_type, mis_distance_x, mis_distance_y, mis_angle, radial_stiffness, bending_stiffness, input_torque=0, load_torque=0)

run(node, unb_magnitude, unb_phase, speed, t, **kwargs)

Run analysis for the system with misalignment given an unbalance force.

System time response is simulated.

Parameters:

nodelist, int

Node where the unbalance is applied.

unb_magnitudelist, float

Unbalance magnitude (kg.m).

unb_phaselist, float

Unbalance phase (rad).

speedfloat or array_like, pint.Quantity

Rotor speed.

tarray

Time array.

**kwargsoptional

The Newmark method can be chosen by setting method=’newmark’. Additional keyword arguments can be passed to define the parameters of the Newmark method if it is used (e.g. gamma, beta, tol, …). See ross.utils.newmark for more details. Other keyword arguments can also be passed to be used in numerical integration (e.g. num_modes). See Rotor.integrate_system for more details.

Returns:

resultsross.TimeResponseResults

For more information on attributes and methods available see: ross.TimeResponseResults