Shaft flexibility effects on aeroelastic stability of a rotating bladed disk

1989 ◽  
Vol 5 (6) ◽  
pp. 718-726 ◽  
Author(s):  
Naim Khader ◽  
Robert Loewy
Keyword(s):  
Aeroelastic Stability ◽  
Bladed Disk ◽  
Shaft Flexibility

Blade Mistuning Coupled With Shaft Flexibility Effects in Rotor Aeroelasticity

1989 ◽  
Author(s):  
Naim Khader ◽  
Robert G. Loewy
Keyword(s):  
Equations Of Motion ◽  
Governing Equations ◽  
Aeroelastic Stability ◽  
Stability Boundaries ◽  
Coriolis Forces ◽  
Bladed Disk ◽  
Out Of Plane ◽  
Shaft Flexibility ◽  
Rotor Aeroelasticity ◽  
Plane Deformations

The effect of bladed-disk polar dissymmetry, resulting from variations in mass from one blade to another, on aeroelastic stability boundaries for a fan stage is presented. In addition to both in-plane and out-of-plane deformations of the bladed-disk, bending of the supporting shaft in two planes is considered, and the resulting Coriolis forces and gyroscopic moments are included in the analysis. A quasi-steady aerodynamics approach is combined with the Lagrangian method to develop the governing equations of motion for the flexible bladed-disk-shaft assembly. Calculations are performed for an actual fan stage.

scholarly journals Numerical Analysis of Rotating Flexible Blade-Disk-Shaft Systems

1999 ◽  
Author(s):  
O. Repetski ◽  
I. Rygikov ◽  
H. Springer
Keyword(s):  
Machine Building ◽  
Structural Components ◽  
Dynamic Interactions ◽  
Element Analysis ◽  
Bladed Disk ◽  
Modal Reduction ◽  
Shaft Flexibility ◽  
Rotating Shafts ◽  
And Shifts

The theory, the algorithms and program package BLADIS (BLAded DIsk Simulation) for strength calculations of rotating flexible blade-disk-shaft assemblies have been worked out. The formulation is based on a finite element analysis of the rotating cyclic structures and modal reduction. The stresses in different zones of the structural components due to influence of centrifugal and temperature forces using static analysis and vibration are calculated. The results obtained show, how shaft flexibility influence on stresses and frequencies. Analysis of influence of blade geometric parameters on disk-shaft stresses is presented. The results obtained by dynamic analysis show that the chosen reduction does not reduce the quality of the model and illustrate its capability to deal with rotating shafts usually calculated using the rotordynamic approach. Finally, the possible dynamic interactions between shaft and disk components are described. This information is used for bladed disks and rotors optimization leading to a reduction of resonance displacements, stress levels and shifts of natural frequencies of rotating flexible blade-disk-shaft assemblies from dangerous resonances. The numerical results are carried in leading machine building companies in Russia.

Mistuning and Structural Coupling Effects on Flutter of Turbomachinery Blades

2013 ◽  
Vol 482 ◽  
pp. 311-314
Author(s):  
Zhi Zhong Fu ◽  
Yan Rong Wang
Keyword(s):  
Influence Coefficient ◽  
Aeroelastic Stability ◽  
Disk System ◽  
Structural Coupling ◽  
Bladed Disk ◽  
Unsteady Aerodynamic ◽  
Simplified Method ◽  
Influence Coefficient Method ◽  
Turbomachinery Blades ◽  
Coefficient Method

A fast numerical method based on aeroelastic eigenvalue analysis is applied to study the effects of mistuning on the aeroelastic stability of turbomachinery blades in which the structural coupling is included by a simplified method and an influence coefficient method is employed to deal with the unsteady aerodynamic effects. Results show that there exists an optimal mistuning amount at which the system has the best aeroelastic stability. Structural coupling almost has no effects on aeroelastic stability of a tuned system. But the benefit of alternate frequency mistuning to aeroelastic stability is inhibited drastically when structural coupling is introduced into the bladed disk system.

Maximum Resonant Response of Mistuned Bladed Disks

1984 ◽  
Vol 106 (2) ◽  
pp. 218-223 ◽  
Author(s):  
J. C. MacBain ◽  
P. W. Whaley
Keyword(s):  
Closed Form Expression ◽  
Resonant Response ◽  
Aeroelastic Stability ◽  
Bladed Disks ◽  
Response Characteristics ◽  
Bladed Disk ◽  
Damping Characteristics ◽  
Modal Damping ◽  
Modes Of Vibration ◽  
The Individual

The turbomachinery bladed disks used in today’s advanced turbine engines must meet strict standards with regard to aeroelastic stability and forced resonant response. One structural characteristic of bladed disks that can significantly impact both of these areas is that of bladed disk mistuning. Mistuning occurs when some circumferential asymmetry exists in the bladed disk. This asymmetry can be due to such things as mass or stiffness eccentricity or slight variations in the individual blade properties and occurs in all bladed disks to a greater or lesser extent. One important structural phenomenon resulting from mistuning is the splitting of the bladed disk’s diametral modes of vibration into “twin” or “dual” modes. The presence of dual mode characteristics in a bladed disk can significantly affect either or both of its aeroelastic stability and resonant response characteristics. The present paper, expanding upon the earlier works of Tobias and Arnold [1] and of Ewins [2] addresses the prediction of the maximum resonant response of a mistuned bladed disk having closely spaced dual modes as a function of mode mistuning and modal damping. A closed form expression is derived for the maximum forced resonant response. A discussion of mistune and damping characteristics of typical turbomachinery bladed disks is also presented.

scholarly journals A Finite Element Approach to the Analysis of Rotating Bladed-Disk Assemblies Coupled With Flexible Shaft

1994 ◽  
Author(s):  
Wen Zhang ◽  
Wenliang Wang ◽  
Hao Wang ◽  
Jiong Tang
Keyword(s):  
Finite Element ◽  
Degrees Of Freedom ◽  
Coupled System ◽  
Equation Of Motion ◽  
Coupled Systems ◽  
The Finite Element Method ◽  
Bladed Disk ◽  
Modal Synthesis ◽  
Element Approach ◽  
Final Equation

A method for dynamic analysis of flexible bladed-disk/shaft coupled systems is presented in this paper. Being independant substructures first, the rigid-disk/shaft and each of the bladed-disk assemblies are analyzed separately in a centrifugal force field by means of the finite element method. Then through a modal synthesis approach the equation of motion for the integral system is derived. In the vibration analysis of the rotating bladed-disk substructure, the geometrically nonlinear deformation is taken into account and the rotationally periodic symmetry is utilized to condense the degrees of freedom into one sector. The final equation of motion for the coupled system involves the degrees of freedom of the shaft and those of only one sector of each of the bladed-disks, thereby reducing the computer storage. Some computational and experimental results are given.

Mistuning identification in a bladed disk using wavelet packet transform

2017 ◽  
Vol 229 (3) ◽  
pp. 1275-1295 ◽  
Author(s):  
N. Jamia ◽  
P. Rajendran ◽  
S. El-Borgi ◽  
M. I. Friswell
Keyword(s):  
Wavelet Packet ◽  
Wavelet Packet Transform ◽  
Bladed Disk
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