A multimass model with non-linear modal damping for SSR analysis of turbine generators

2009 ◽  
Author(s):  
Zhang Xiaojin ◽  
Xie Xiaorong
Keyword(s):  
Ssr Analysis ◽  
Turbine Generators ◽  
Modal Damping ◽  
Non Linear

Effective damping for SSR analysis of parallel turbine-generators

1988 ◽  
Vol 3 (4) ◽  
pp. 1441-1448 ◽  
Author(s):  
B.L. Agrawal ◽  
R.G. Farmer
Keyword(s):  
Ssr Analysis ◽  
Turbine Generators

Model-Based Unbalance Estimation for Steam Turbine-Generators

2007 ◽  
Author(s):  
Tachung Yang ◽  
Kwang-Lu Koai ◽  
Chun-Yi Lin ◽  
Wen-Ming Xu
Keyword(s):  
Parameter Estimation ◽  
Steam Turbine ◽  
Coefficient Matrix ◽  
Influence Coefficient ◽  
Turbine Generator ◽  
Model Based ◽  
Turbine Generators ◽  
Modal Damping ◽  
Bode Plots ◽  
Diagnosis Tool

As demanded for parameter estimation based on the measured signals, a model-based method to estimate the unbalance distribution of steam turbine-generators due to unbalance response was proposed in this paper. The equivalent modal damping ratios for each mode estimated by GA from the measured Bode plots are incorporated into the modal models. A finite number of the modes are used to calculate the influence coefficient matrix. Finally, the equivalent unbalance distribution on the selected correction planes is estimated based on the measured responses. The merit of this approach is that no test run of trial mass is required. The feasibility of this method is demonstrated using a steam turbine-generator. The method presented not only provides a useful means for balancing work, but also can be further developed into an identification and diagnosis tool.

Analysis of shaft torsional phenomena in governing large steam turbine generators with non-linear valve stroking

1999 ◽  
Vol 14 (3) ◽  
pp. 379-385 ◽  
Author(s):  
T.J. Hammons ◽  
R.C.K. Goh
Keyword(s):  
Steam Turbine ◽  
Turbine Generators ◽  
Non Linear

Non-Linear Free Vibration of Submerged Floating Tunnel Tether

2014 ◽  
Vol 580-583 ◽  
pp. 1388-1391 ◽  
Author(s):  
Zhi Bin Su ◽  
Sheng Nan Sun
Keyword(s):  
Free Vibration ◽  
Damping Ratio ◽  
Direct Proportion ◽  
Initial Tension ◽  
Modal Damping Ratio ◽  
Inverse Proportion ◽  
Modal Damping ◽  
Non Linear ◽  
Out Of Plane ◽  
Submerged Floating Tunnel

Taking the free vibration system of a submerged floating tunnel tether as research object, the non-linear free vibration equation was set up. By means of Galerkin method, the partial differential equation was transformed into a set of ordinary ones. The damping ratios of the first four modes were obtained after complex eigenvalue analysis. Subsequently, effects of inclination, sag, initial tension force and length of tether on its modal damping ratios were analyzed. The results show that inclination and sag of tether merely affect the damping ratio of first in-plane mode; they have no effect on the damping ratios of higher order in-plane modes and out of plane modes; the first in-plane modal damping ratio of tether is in direct proportion to its inclination, whereas in inverse proportion to its sag; the first modal damping ratio of tether (both in-plane and out of plane) is in direct proportion to its length, whereas in inverse proportion to its initial tension.

scholarly journals Non-Linear Modal Analysis for Bladed Disks With Friction Contact Interfaces

2008 ◽  
Author(s):  
Denis Laxalde ◽  
Loi¨c Salles ◽  
Laurent Blanc ◽  
Fabrice Thouverez
Keyword(s):  
Modal Analysis ◽  
Equations Of Motion ◽  
Dynamical Behaviour ◽  
Forced Response ◽  
Fretting Wear ◽  
External Excitation ◽  
Bladed Disk ◽  
Dynamical Simulation ◽  
Modal Damping ◽  
Non Linear

A method for non-linear modal analysis of mechanical systems with contact and friction interfaces is proposed. It is based on a frequency domain formulation of the dynamical system’s equations of motion. The dissipative aspects of these non-linearities result in complex eigensolutions and the modal parameters (natural frequency and modal damping) can be obtained without any assumptions on the external excitation. The generality of this approach makes it possible to address any kind of periodic regimes, in free and forced response. In particular, stability analysis in flutter applications can be performed. Applications for the design of friction ring dampers for blisks and for the dynamical simulation of bladed disk with dovetail attachment are proposed. Finally, we propose a study of dynamical behaviour coupling with the calculation of fretting-wear at the interfaces based on non-linear modal characterization.

B. The Non-Linear Calculations for Pulsating Stars

1967 ◽  
Vol 28 ◽  
pp. 105-176
Author(s):  
Robert F. Christy
Keyword(s):  
Major Part ◽  
Afternoon Session ◽  
Discussion Session ◽  
Pulsating Stars ◽  
Fourth Symposium ◽  
Non Linear ◽  
Considerable Discussion ◽  
Informal Approach ◽  
Preceding Session

(Ed. note: The custom in these Symposia has been to have a summary-introductory presentation which lasts about 1 to 1.5 hours, during which discussion from the floor is minor and usually directed at technical clarification. The remainder of the session is then devoted to discussion of the whole subject, oriented around the summary-introduction. The preceding session, I-A, at Nice, followed this pattern. Christy suggested that we might experiment in his presentation with a much more informal approach, allowing considerable discussion of the points raised in the summary-introduction during its presentation, with perhaps the entire morning spent in this way, reserving the afternoon session for discussion only. At Varenna, in the Fourth Symposium, several of the summaryintroductory papers presented from the astronomical viewpoint had been so full of concepts unfamiliar to a number of the aerodynamicists-physicists present, that a major part of the following discussion session had been devoted to simply clarifying concepts and then repeating a considerable amount of what had been summarized. So, always looking for alternatives which help to increase the understanding between the different disciplines by introducing clarification of concept as expeditiously as possible, we tried Christy's suggestion. Thus you will find the pattern of the following different from that in session I-A. I am much indebted to Christy for extensive collaboration in editing the resulting combined presentation and discussion. As always, however, I have taken upon myself the responsibility for the final editing, and so all shortcomings are on my head.)

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