scholarly journals Local Sensitivity Analysis of Steady-State Response of Rotors with Rub-Impact to Parameters of Rubbing Interfaces

2021 ◽  
Vol 11 (3) ◽  
pp. 1307
Author(s):  
Minghong Jiang ◽  
Zhaoli Zheng ◽  
Yonghui Xie ◽  
Di Zhang
Keyword(s):  
Sensitivity Analysis ◽  
Steady State ◽  
Duffing Oscillator ◽  
Harmonic Balance Method ◽  
Friction Model ◽  
Design Parameters ◽  
Steady State Response ◽  
Local Sensitivity ◽  
Local Sensitivity Analysis ◽  
State Response

Local sensitivity analysis, which describes the relative importance of specific design parameters to the response of systems, is crucial for investigating dominant factors in optimal design. In this paper, local sensitivity analysis of the response of rotors with rub-impact to parameters of rubbing interfaces is carried out. The steady-state motion of the rotor is evaluated by a harmonic balance method and the sensitivity coefficients for every rotation speed over the speed range are derived analytically. Two classical models, including the Duffing oscillator and the gap model, are utilized to validate the accuracy and capability of the adopted methods and high accuracy is shown. Numerical investigations of sensitivities of steady-state response of rotors to parameters of rubbing interfaces are then carried out, based on a lumped Jeffcott rotor and a finite element model respectively. Conclusions are drawn that the response of rotors subjected to rubbing problems is more sensitive to initial clearance than other parameters of the applied friction model. With increase of initial gap, the response of rotors becomes more sensitive and the range of region subjected to rub-impact forces shrinks until the separation of rotor and stator.

Steady-State Response and Stability of Rotating Composite Blades With Frictional Damping

1998 ◽  
Vol 120 (1) ◽  
pp. 131-139 ◽  
Author(s):  
T. N. Shiau ◽  
J. S. Rao ◽  
Y. D. Yu ◽  
S. T. Choi
Keyword(s):  
Steady State ◽  
Stability Analysis ◽  
Excitation Frequency ◽  
Harmonic Balance Method ◽  
Composite Plates ◽  
Steady State Response ◽  
Friction Damping ◽  
State Response ◽  
Direct Integration Method ◽  
Composite Blades

Friction dampers are widely used to improve the performance of rotating blades. This paper is concerned with the steady state response and stability analysis of rotating composite plates in the presence of non linear friction damping. Direct Integration Method (DIM) and Harmonic Balance Method (HBM) are used to determine the steady state response due to periodic lateral external forces. In addition, an alternate procedure, Hybrid Method (HM) is proposed for this analysis to substantiate the results from DIM and HBM. The analysis shows that the steady state response is a function of friction damping magnitude as well as its location besides the excitation frequency and the rotational speed. A stability analysis of the composite blades is also made by including periodic in-plane excitation using Floquet-Liapunov theory.

Steady-State Response of Continuous Nonlinear Rotor-Bearing Systems Using Analytical Approach

1998 ◽  
Vol 120 (4) ◽  
pp. 751-758 ◽  
Author(s):  
J. W. Zu ◽  
Z. Y. Ji
Keyword(s):  
Steady State ◽  
Harmonic Balance Method ◽  
Beam Theory ◽  
Distributed Parameter ◽  
Steady State Response ◽  
State Response ◽  
Rotor Bearing ◽  
Continuous Modeling ◽  
Close Form ◽  
First Time

A continuous modeling of nonlinear rotor-bearing systems is presented in this paper. The shaft is treated as a distributed parameter system using Timoshenko beam theory. A close form, steady-state response of the system is solved analytically for the first time. For cubic nonlinear bearings, the response is composed of three components, synchronous vibration, subsynchronous, and supersynchronous vibration. The harmonic balance method is used to calculate the nonlinear bearing forces. Two examples of nonlinear rotor-bearing systems are shown to illustrate the analysis procedure and the nonlinear characteristics of the system. Solutions from simplified systems are also derived for comparison.

Closed-Form Steady-State Response Solution of the Twin Rotor Damper and Experimental Validation

2017 ◽  
Vol 139 (2) ◽  
Author(s):  
Richard Bäumer ◽  
Uwe Starossek
Keyword(s):  
Steady State ◽  
Closed Form ◽  
Closed Form Solution ◽  
Form Solution ◽  
Design Parameters ◽  
Control Force ◽  
Steady State Response ◽  
Active Mass ◽  
State Response ◽  
Twin Rotor

In previous research, the twin rotor damper (TRD), an active mass damper, was presented including control algorithms for monofrequent vibrations. In a preferred mode of operation, the continuous rotation mode, two eccentric masses rotate in opposite directions about two parallel axes with a mostly constant angular velocity. The resulting control force is harmonic. Within this paper, the steady-state response of a single-degree-of-freedom (SDOF) oscillator subjected to a harmonic excitation force with and without the TRD is studied. A closed-form solution is presented and validated experimentally. It is shown that the TRD provides damping to the SDOF oscillator until a certain frequency ratio is reached. The provided damping is not only dependent on the design parameters of the TRD but also depends on the steady-state vibration amplitude. The solution serves as a powerful design tool for dimensioning the TRD. The analytical closed-form solution is applicable for other active mass dampers.

Steady State Response and Stability of Rotating Composite Blades With Frictional Damping

1996 ◽  
Author(s):  
T. N. Shiau ◽  
J. S. Rao ◽  
Y. D. Yu ◽  
S. T. Choi
Keyword(s):  
Steady State ◽  
Stability Analysis ◽  
Excitation Frequency ◽  
Harmonic Balance Method ◽  
Composite Plates ◽  
Steady State Response ◽  
Friction Damping ◽  
State Response ◽  
Direct Integration Method ◽  
Composite Blades

Friction dampers are widely used to improve the performance of rotating blades. This paper is concerned with the steady stale response and stability analysis of ratating composite plates in the presence of non linear friction damping. Direct Integration Method (DIM) and Harmonic Balance Method (HBM) are used to determine the steady state response due to periodic lateral external forces. In addition, an alternate procedure, Hybrid Method (HM) is proposed for this analysis to substantiate the results from DIM and HBM. The analysis shows that the steady state response is a function of friction damping magnitude as well as its location besides the excitation frequency and the rotational speed. A stability analysis of the composite blades is also made by including periodic in-plane excitation using Floquet-Liapunov theory.

Modeling and Analysis of Friction Rim Dampers for Blisks

2005 ◽  
Author(s):  
Denis Laxalde ◽  
Jean-Jacques Sinou ◽  
Fabrice Thouverez ◽  
Jean-Pierre Lombard
Keyword(s):  
Steady State ◽  
Harmonic Balance ◽  
Harmonic Balance Method ◽  
Design Guidelines ◽  
Lumped Parameter Model ◽  
Dynamical Analysis ◽  
Steady State Response ◽  
Modeling And Analysis ◽  
State Response ◽  
Lumped Parameter

A damping strategy for blisks of turbomachinery involving a friction rim is investigated. These rims, located in grooves underside the wheel of the blisks, are held in by centrifugal loads and the energy is dissipated when relative motions between the rim and the disk occur. A method of dynamical analysis of a cyclic blisk nonlinearly coupled with a split rim is presented: the steady-state response being calculated using an multi-harmonic balance method. Numerical simulations on a lumped-parameter model are presented for several damper characteristics and several excitation configurations. From these results, the performance of this damping strategy is discussed and some design guidelines are given. Finally the influence of mistuning on the damping performances is analysed.

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