VIBRATIONS OF A ROTOR SYSTEM WITH MULTIPLE COUPLER OFFSETS

2011 ◽  
Vol 35 (1) ◽  
pp. 81-100
Author(s):  
Chao-Yang Tsai ◽  
Shyh-Chin Huang
Keyword(s):  
Transfer Matrix ◽  
Transfer Matrix Method ◽  
Rotational Speed ◽  
Matrix Method ◽  
Rotor System ◽  
Response Amplitude ◽  
External Excitation ◽  
Phase Offset ◽  
Major Response ◽  
Before And After

In this paper, a transfer matrix method (TMM) for rotors with multiple coupler offsets was derived. The studies showed the coupler’s stiffness altered the rotor’s critical speeds but offset caused additional external excitation. The cases of two offsets in- and anti-phase in a typical rotor were given as examples. In the in-phase case, significantly increased response amplitude occurred at lower rotational speed and the increase was linearly proportional to the offset value. As to the anti-phase case, the increased response was insignificant, implying an opposite offset would cancel out a major response of the previous offset. The whirling orbits before and after the offset couplers were also illustrated. The results, as expected, showed the in-phase offset displayed much larger radii than the anti-phase’s. The rotor’s orbits changed the whirling direction once the rotation fell within a certain range and this feature seemed to be unaffected by coupler offsets.

Dynamic Analysis of Complex Composite Rotor Systems With Substructure Transfer Matrix Method

1985 ◽  
Author(s):  
Yan Litang
Keyword(s):  
Dynamic Analysis ◽  
Transfer Matrix ◽  
Transfer Matrix Method ◽  
Matrix Method ◽  
Synthesis Method ◽  
Frequency Equation ◽  
Rotor System ◽  
Combination Method ◽  
Rotor Systems ◽  
Modal Synthesis

A substructure transfer matrix method for the dynamic analysis of multi-Rotor systems and complex composite systems is presented. When calculating, the rotor system should be decomposed into several single rotor shafts (substructures). Corresponding unknown external loads and deflections are applied to the separated surfaces, rigid support sections and ball joint sections respectively to replace the original connections. According to the connective and boundary conditions of the whole rotor system, a system of equations is established, from which the frequency equation results. The calculating formulas of vibration modes and of unbalanced response will be easily formed by linear combination method. All computations are performed with the transfer matrix method. This method is intelligible, readily programmed and much simpler than the current transfer matrix method and modal synthesis method.

scholarly journals Transfer Matrix Method to Vibration Analysis of Rotors with Coupler Offsets

2013 ◽  
Vol 20 (1) ◽  
pp. 97-108 ◽  
Author(s):  
Chao-Yang Tsai ◽  
Shyh-Chin Huang
Keyword(s):  
Transfer Matrix ◽  
Transfer Matrix Method ◽  
Matrix Method ◽  
Vibration Analysis ◽  
Combined Effect ◽  
Dynamic Effects ◽  
External Excitation ◽  
Global And Local

In this paper a general transfer matrix method (TMM) for rotors containing global and local coupler offset was derived. Rotor response due to imbalances and offsets are then studied via the developed method. The studies showed both global and local offsets played as an external excitation that is a combined effect of all the elements behind the offset. Differences between global offset and local offset were compared and the results showed both types basically retain the same mode patterns but different jumps at the offset. The global offset, yet, imposed more significant dynamic effects since all the offsets accumulate thereafter. The whirling orbits in front and behind the offset were illustrated as well. The results, as expected, showed global offset appeared much larger radii especially after offset. The rotor's whirling orientation reversed, as rotation fell within a certain range and this feature was not changed by offsets. The TMM proposed by this study can be well applied to multiple global and local offsets.

scholarly journals Investigation of the Steady-State Response of a Dual-Rotor System With Inter-Shaft Squeeze Film Damper

1985 ◽  
Author(s):  
Qihan Li ◽  
Litang Yan ◽  
James F. Hamilton
Keyword(s):  
Steady State ◽  
Transfer Matrix ◽  
Transfer Matrix Method ◽  
Matrix Method ◽  
Rotor System ◽  
Squeeze Film ◽  
Turbine Engine ◽  
Squeeze Film Damper ◽  
State Response ◽  
Unbalance Response

This paper presents an analysis of the steady-state unbalance response of a dual-rotor gas turbine engine with a flexible intershaft squeeze film damper using a simplified transfer matrix method. The simplified transfer matrix method is convenient for the evaluation of the critical speed and response of the rotor system with various supports, shaft coupling, intershaft bearing, etc. The steady-state unbalance response of the rotor system is calculated for different shaft rotation speeds. The damping effects of an intershaft squeeze film damper with different radial clearances under various levels of rotor unbalance are investigated.

A Finite-Width Crack Model for Rotor Dynamic Analysis by Transfer Matrix Method

2006 ◽  
Vol 324-325 ◽  
pp. 1003-1006
Author(s):  
Ke Ming Wang ◽  
Song Xiang
Keyword(s):  
Dynamic Analysis ◽  
Transfer Matrix ◽  
Transfer Matrix Method ◽  
Matrix Method ◽  
Transverse Crack ◽  
Rotor System ◽  
Crack Model ◽  
Finite Width ◽  
Stiffness Reduction ◽  
Rotor Dynamic

Understanding dynamic behavior of a rotor system with a transverse crack is of great significance for operation reliability of rotating machinery. The transfer matrix method is widely used for rotor dynamic analysis, but it encounters difficulties modeling a crack. This study proposes a finite-width crack model that simulates the local stiffness reduction effect of a gaping crack in transfer matrix method. This model is obtained by comparing finite element analysis results of a shaft with a zero-width crack and its counterpart transfer matrix calculation results with a trial equivalent finite-width slot. Different shaft geometry and loading modes are considered to improve the generality of the model. An application example is given that uses the proposed model to calculate critical speeds of a multi-disk rotor system with a transverse crack at different positions.

Stability Analysis of Dual Rotor System by Extended Transfer Matrix Method

1989 ◽  
Author(s):  
K. D. Gupta ◽  
K. Gupta ◽  
K. Athre
Keyword(s):  
Transfer Matrix ◽  
Stability Criterion ◽  
Transfer Matrix Method ◽  
Matrix Method ◽  
Potential Method ◽  
Rotor System ◽  
Junction Conditions ◽  
Rotor Systems ◽  
Margin Of Stability ◽  
The Stability

This paper presents a general formulation for the stability problem of a linear model of dual rotor system with intershaft bearing(s) employing an ‘extended’ transfer matrix method [9] using complex variables. The stability criterion employed is essentially an extension of leonhard’s stability criterion. An alternative concept of ‘margin of stability’ has been suggested. In contrast to other methods, the present formulation maintains the integrity of dual rotor system in totality, by considering exact junction conditions at intershaft bearing. And it is felt that it would prove to be an potential method for analyzing the stability of complex rotor systems.

Investigation of the Steady-State Response of a Dual-Rotor System With Intershaft Squeeze Film Damper

1986 ◽  
Vol 108 (4) ◽  
pp. 605-612 ◽  
Author(s):  
Qihan Li ◽  
Litang Yan ◽  
J. F. Hamilton
Keyword(s):  
Steady State ◽  
Transfer Matrix ◽  
Transfer Matrix Method ◽  
Matrix Method ◽  
Rotor System ◽  
Squeeze Film ◽  
Turbine Engine ◽  
Squeeze Film Damper ◽  
State Response ◽  
Unbalance Response

This paper presents an analysis of the steady-state unbalance response of a dual-rotor gas turbine engine with a flexible intershaft squeeze film damper using a simplified transfer matrix method. The simplified transfer matrix method is convenient for the evaluation of the critical speed and response of the rotor system with various supports, shaft coupling, intershaft bearing, etc. The steady-state unbalance response of the rotor system is calculated for different shaft rotation speeds. The damping effects of an intershaft squeeze film damper with different radial clearances under various levels of rotor unbalance are investigated.

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