Nonlinear dynamics of a flexible rotor on tilting pad journal bearings experiencing rub–impact

Tofighi-Niaki, Ebrahim; Asgharifard-Sharabiani, Pouya; Ahmadian, Hamid

doi:10.1007/s11071-018-4535-0

Cited by 19 publications

(10 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Furthermore, the TPJBs hydrodynamic and solid-to-solid contact forces were determined at different wear severities for an unbalanced rotor-TPJB system. The equations of motion of the rotor-TPJB system can be written as follows [36]:…”

Section: Mathematical Model Descriptionmentioning

confidence: 99%

Dynamic of a Flexible Rotor-Bearing System Supported by Worn Tilting Journal Bearings Experiencing Rub-Impact

Tofighi-Niaki¹,

Safizadeh²

2023

Preprint

View full text Add to dashboard Cite

Wear usually occurs in the loaded part of hydrodynamic bearings and leads the bearing geometry imperfections. This paper investigates the effects of wear-induced geometric imperfections of tilting pad journal bearings (TPJBs) on the dynamic behavior of the system. Furthermore, the effect of wear on the journal-bearing rub-induced contact pressure severity is investigated. A novel tribo-dynamic model is proposed for a flexible rotor-worn TPJB which integrates a mixed elastohydrodynamic model with a rotor-worn TPJB thermal and dynamic model to assess the effects of the bearing wear progression on the rotor-TPJB behavior. Based on the results, wear changes the temperature distribution of the pads and oil film as well as the dynamic behavior of the system. Dynamic simulations reveal a higher vibration level and contact pressure for the worn TPJBs near the system's critical speed and service speed. Finally, thermal and dynamic condition indicators are suggested to detect TPJB wear severity at its early stages.

show abstract

Section: Mathematical Model Descriptionmentioning

confidence: 99%

Dynamic of a Flexible Rotor-Bearing System Supported by Worn Tilting Journal Bearings Experiencing Rub-Impact

Tofighi-Niaki¹,

Safizadeh²

2023

Preprint

View full text Add to dashboard Cite

show abstract

“…Substituting it into equation (7) and converting it into polar coordinates, the dimensionless governing equation in polar coordinate get r 00 À rc…”

Section: Mathematical Derivation Of Phase Differencementioning

confidence: 99%

“…6 These two patterns can be distinguished through the stability evaluation of the periodic solution of the system. There is extensive research work on rub-impact phenomenon and stability, [7][8][9] mainly including the stability of parameter regions and bifurcation boundaries analysis of rub-impact solution, [10][11][12] bifurcation and chaos characteristics of the rotor-stator system, 13,14 and analysis about the synchronous full annular rub and partial rub. 15,16 Xu et al 17 studied the full annular rub motion of a Jeffcott rotor and its dynamic stability by linear perturbation method and by the Routh-Hurwitz criterion, finding that the full annular rub motions exist in a wide spinning region of the rotor.…”

Section: Introductionmentioning

confidence: 99%

Phase difference and stability of a shaft mounted a dry friction damper: Effects of viscous internal damping and gyroscopic moment

Huang

Tan

Lu³

2021

Advances in Mechanical Engineering

View full text Add to dashboard Cite

This study investigates the stability and phase difference of a shaft mounted a dry friction damper with effects of viscous internal damping and gyroscopic moment. The equations of the system with the vibration reduction effect of the dry friction damper on the shaft are derived in the form of the rectangular coordinate and polar coordinate in the vicinity of critical speed. The phase difference characteristics in the rub-impact process and its physical mechanism are analyzed by mathematical derivation. The characteristic equation is studied to investigate the stability of the periodic solution. Effects of different parameters of the system, especially viscous internal damping of the composite shaft and gyroscopic moment on the phase difference and stability regions are presented in detail by analytical and numerical simulation based on a helicopter tailrotor driveline. The experimental investigation is conducted in a test rig to validate theoretical formulas and simulation analysis. The analysis results show that rub impact delays the change of phase difference, viscous internal damping improves the stability of synchronous full annual rub solution, and gyroscopic moment affects the increase of the phase difference.

show abstract

“…Loı €c Peletan et al proposed a quasi-periodic harmonic balance method (HBM) coupled with a pseudo arc-length continuation algorithm to predict the steady-state dynamic behavior of rotor-stator system with rub-impact (Peletan et al, 2014). Ebrahim Tofighi-Niaki et al studied the nonlinear dynamics of a flexible rotor on tilting pad journal bearings with rub-impact (Tofighi-Niaki et al, 2018). Fei et al analyzed the nonlinear vibration behavior of the whole aeroengine including rolling bearing and squeeze film damper under rub-impact fault (Liu et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

“…Ebrahim Tofighi-Niaki et al. studied the nonlinear dynamics of a flexible rotor on tilting pad journal bearings with rub–impact (Tofighi-Niaki et al. , 2018).…”

Section: Introductionmentioning

confidence: 99%

Nonlinear vibration response of a helicopter supercritical tail rotor drive shaft equipped with a dry friction damper

Song

Chen

et al. 2022

JIMSE

View full text Add to dashboard Cite

PurposeThe supercritical design of tail rotor drive shaft has attracted more attention in helicopter design due to its high power–weight ratio and low maintenance cost. However, there exists excessive vibration when the shaft passes through the critical frequency. Dry friction damper is the equipment applied to the drive shaft to suppress the excessive vibration. In order to figure out the damping mechanism of the dry friction damper and improve the damping efficiency, the dynamic model of the shaft/damper system is established based on the Jeffcott rotor model.Design/methodology/approachThe typical frequency response of the system is studied through bifurcation diagrams, amplitude-frequency characteristic curves and waterfall frequency response spectrum. The typical transient responses under frequency sweeps are also obtained.FindingsThe results show that the response of the system changes from periodic no-rub motion to quasi-periodic rub-impact motion, and then to synchronous full annular rub-impact, and finally, back to periodic no-rub motion. The slip of the rub-impact ring improves the stability of the system. Besides, the effects of the system parameters including critical dry friction force, rub-impact friction coefficient, initial clearance on the stability and the vibration damping capacity are studied. It is observed that the stability changes significantly varying the three parameters respectively. The vibration damping capacity is mainly affected by the critical dry friction force and the initial clearance.Originality/valuePresented results provide guidance for the design of the dry friction damper.

show abstract

Nonlinear dynamics of a flexible rotor on tilting pad journal bearings experiencing rub–impact

Cited by 19 publications

References 26 publications

Dynamic of a Flexible Rotor-Bearing System Supported by Worn Tilting Journal Bearings Experiencing Rub-Impact

Dynamic of a Flexible Rotor-Bearing System Supported by Worn Tilting Journal Bearings Experiencing Rub-Impact

Phase difference and stability of a shaft mounted a dry friction damper: Effects of viscous internal damping and gyroscopic moment

Nonlinear vibration response of a helicopter supercritical tail rotor drive shaft equipped with a dry friction damper

Contact Info

Product

Resources

About