scholarly journals Vibrational Response Analysis of Mistuned Bladed Disk System of Grouped Blades

1998 ◽  
Author(s):  
Y. Kaneko ◽  
K. Mori ◽  
H. Ohyama ◽  
E. Watanabe
Keyword(s):  
Synthesis Method ◽  
Forced Response ◽  
Response Analysis ◽  
Analysis Method ◽  
Disk System ◽  
Vibrational Response ◽  
Bladed Disk ◽  
System A ◽  
Vibrational Characteristics ◽  
Grouped Blades

For the purpose of the efficient analysis of a mistuned bladed disk system, a new analysis method which applies the substructure synthesis method and the modal analysis method is proposed. Using the proposed method, the vibrational characteristics of the grouped blades structure are studied. From the results, it is found that the grouped blades structure is very sensitive to the mistuning. It is also found that the mixed grouped blades structure (a bladed disk system consisting of some different types of grouped blades relating to the number of blades contained) has an undesirable effect on the forced response. Moreover, by comparing the vibrational characteristics of the integral shroud blades (ISB) structure with those of the grouped blades structure, it is clarified that the reliability of the ISB structure is superior to other structures also from the viewpoint of the mistuning.

Investigation of Damping Potential of Strip Damper on a Real Turbine Blade

2016 ◽  
Author(s):  
M. Afzal ◽  
I. Lopez Arteaga ◽  
L. Kari ◽  
V. Kharyton
Keyword(s):  
Boundary Conditions ◽  
Dynamic Properties ◽  
Equations Of Motion ◽  
Iterative Solution ◽  
Element Model ◽  
Forced Response ◽  
Contact Forces ◽  
Response Analysis ◽  
Bladed Disk ◽  
Different Types

This paper investigates the damping potential of strip dampers on a real turbine bladed disk. A 3D numerical friction contact model is used to compute the contact forces by means of the Alternate Frequency Time domain method. The Jacobian matrix required during the iterative solution is computed in parallel with the contact forces, by a quasi-analytical method. A finite element model of the strip dampers, that allows for an accurate description of their dynamic properties, is included in the steady-state forced response analysis of the bladed disk. Cyclic symmetry boundary conditions and the multiharmonic balance method are applied in the formulation of the equations of motion in the frequency domain. The nonlinear forced response analysis is performed with two different types of boundary conditions on the strip: (a) free-free and (b) elastic, and their influence is analyzed. The effect of the strip mass, thickness and the excitation levels on the forced response curve is investigated in detail.

Transient Forced Response Analysis of Mistuned Steam Turbine Blades During Startup and Coastdown

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Christian Siewert ◽  
Heinrich Stüer
Keyword(s):  
Mechanical Model ◽  
Turbine Blades ◽  
Forced Vibrations ◽  
Forced Response ◽  
The Self ◽  
Response Analysis ◽  
Computationally Efficient ◽  
Bladed Disk ◽  
Steam Turbine Blades ◽  
Number Of Publications

It is well known that the vibrational behavior of a mistuned bladed disk differs strongly from that of a tuned bladed disk. A large number of publications dealing with the dynamics of mistuned bladed disks are available in the literature. The vibrational phenomena analyzed in these publications are either forced vibrations or self-excited flutter vibrations. Nearly, all published literature on the forced vibrations of mistuned blades disks considers harmonic, i.e., steady-state, vibrations, whereas the self-excited flutter vibrations are analyzed by the evaluation of the margin against instabilities by means of a modal, or rather than eigenvalue, analysis. The transient forced response of mistuned bladed disk is not analyzed in detail so far. In this paper, a computationally efficient mechanical model of a mistuned bladed disk to compute the transient forced response is presented. This model is based on the well-known fundamental model of mistuning (FMM). With this model, the statistics of the transient forced response of a mistuned bladed disk is analyzed and compared to the results of harmonic forced response analysis.

Maximum Bladed Disk Forced Response From Distortion of a Structural Mode

2002 ◽  
Author(s):  
J. A. Kenyon ◽  
J. H. Griffin ◽  
D. M. Feiner
Keyword(s):  
Forced Response ◽  
Maximum Response ◽  
Strong Response ◽  
Bladed Disk ◽  
System A ◽  
Random Mistuning ◽  
Harmonic Components ◽  
Structural Mode

A method is presented for obtaining maximum bladed disk forced response from distortion of a structural mode. It is shown that maximum response from mode distortion in a bladed disk occurs when the harmonic components of a distorted mode superimpose in a certain manner, causing localization of the mode and strong response in a particular blade. In addition, it is shown that the response of an intentionally mistuned system with maximum response does not change significantly when small random mistuning is added to the system. A method is described for calculating the structural mistuning necessary to obtain the distorted mode that gives maximum response. The theory is validated numerically.

scholarly journals Vibrational Response Analysis of Mistuned Bladed Disk

1994 ◽  
Vol 37 (1) ◽  
pp. 33-40 ◽  
Author(s):  
Yasutomo Kaneko ◽  
Masataka Mase ◽  
Katsuhisa Fujita ◽  
Toshio Nagashima
Keyword(s):  
Response Analysis ◽  
Vibrational Response ◽  
Bladed Disk

Transient Forced Response Analysis of Mistuned Steam Turbine Blades During Start-Up and Coast-Down

2014 ◽  
Author(s):  
Christian Siewert ◽  
Heinrich Stüer
Keyword(s):  
Mechanical Model ◽  
Turbine Blades ◽  
Forced Vibrations ◽  
Forced Response ◽  
Response Analysis ◽  
Computationally Efficient ◽  
Bladed Disk ◽  
Start Up ◽  
Steam Turbine Blades ◽  
Number Of Publications

It is well-known that the vibrational behavior of a mistuned bladed disk differs strongly from that of a tuned bladed disk. A large number of publications dealing with the dynamics of mistuned bladed disks is available in the literature. The vibrational phenomena analyzed in these publications are either forced vibrations or self-excited flutter vibrations. Nearly all published literature on the forced vibrations of mistuned blades disks considers harmonic, i. e. steady-state, vibrations, whereas the self-excited flutter vibrations are analyzed by the evaluation of the margin against instabilities by means of a modal, or rather than eigenvalue, analysis. The transient forced response of mistuned bladed disk is not analyzed in detail so far. In this paper, a computationally efficient mechanical model of a mistuned bladed disk to compute the transient forced response is presented. This model is based on the well-known Fundamental Model of Mistuning. With this model, the statistics of the transient forced response of a mistuned bladed disk is analyzed and compared to the results of harmonic forced response analysis.

scholarly journals Vibrational Response Analysis of a Mistuned Bladed Disk (Grouped Blade)

1997 ◽  
Vol 63 (610) ◽  
pp. 1887-1892 ◽  
Author(s):  
Yasutomo KANEKO ◽  
Kazushi MORI ◽  
Eiichiro WATANABE ◽  
Toshio NAGASHIMA
Keyword(s):  
Response Analysis ◽  
Vibrational Response ◽  
Bladed Disk

scholarly journals Coupled Free Vibration of Spinning Functionally Graded Porous Double-Bladed Disk Systems Reinforced with Graphene Nanoplatelets

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5610
Author(s):  
Tianyu Zhao ◽  
Yu Ma ◽  
Hongyuan Zhang ◽  
Jie Yang
Keyword(s):  
Free Vibration ◽  
Distribution Pattern ◽  
Plate Theory ◽  
Synthesis Method ◽  
Coupled Model ◽  
Graphene Nanoplatelets ◽  
Functionally Graded ◽  
Width Ratio ◽  
Disk System ◽  
Bladed Disk

This paper presents, for the first time, the mechanical model and theoretical analysis of free vibration of a spinning functionally graded graphene nanoplatelets reinforced composite (FG-GPLRC) porous double-bladed disk system. The nanocomposite rotor is made of porous metal matrix and graphene nanoplatelet (GPL) reinforcement material with different porosity and nanofillers distributions. The effective material properties of the system are graded in a layer-wise manner along the thickness directions of the blade and disk. Considering the gyroscopic effect, the coupled model of the double-bladed disk system is established based on Euler–Bernoulli beam theory for the blade and Kirchhoff’s plate theory for the disk. The governing equations of motion are derived by employing the Lagrange’s equation and then solved by employing the substructure mode synthesis method and the assumed modes method. A comprehensive parametric analysis is conducted to examine the effects of the distribution pattern, weight fraction, length-to-thickness ratio, and length-to-width ratio of graphene nanoplatelets, porosity distribution pattern, porosity coefficient, spinning speed, blade length, and disk inner radius on the free vibration characteristics of the FG-GPLRC double-bladed disk system.

Application of a Reduced Order Modeling Technique for Mistuned Bladed Disk-Shaft Assemblies

2007 ◽  
Author(s):  
Bartolome´ Segui´ ◽  
Euro Casanova
Keyword(s):  
Finite Element ◽  
Synthesis Method ◽  
Element Model ◽  
Reduced Order Modeling ◽  
Forced Response ◽  
Modeling Technique ◽  
Disk Model ◽  
Reduced Order ◽  
Bladed Disk ◽  
Global Dynamic

This paper presents a reduced-order modeling technique, based on a component mode synthesis method specifically tailored for bladed disks, that allows the resulting low-order model to be attached to a shaft. Mistuning is included in the bladed disk model and the shaft is modeled using uniaxial finite elements according to the rotordynamic approach. The proposed formulation is applied to an example finite element model of a bladed disk, for both tuned and mistuned blades. Comparisons are made between the reduced model and the full finite element solution for free and forced responses in order to assess the methodology. The forced response amplitudes of the blades are found to vary significantly with the inclusion of a flexible shaft. This work suggest that stage independent analyses might not be adequate for predicting the global dynamic response of rotating assemblies of turbomachines.

Resonant Response of Mistuned Bladed Disk Expressed by Vibratory Stress

2016 ◽  
Author(s):  
Yasutomo Kaneko ◽  
Kazushi Mori ◽  
Hiroharu Ooyama
Keyword(s):  
Stress Response ◽  
Amplification Factor ◽  
Forced Response ◽  
Response Analysis ◽  
Flat Plates ◽  
Bladed Disks ◽  
Displacement Response ◽  
Bladed Disk ◽  
Excited Vibration ◽  
Blade Flutter

Although bladed disks of turbomachinery are nominally designed to be cyclically symmetric (tuned system), the vibration characteristics of all blades on a disk are slightly different due to the manufacturing tolerance, the deviation of the material property, the wear during operation, and so on. These small variations break the cyclic symmetry, and split the eigenvalue pairs. The actual bladed disks with the small variations are referred to a mistuned system. In the forced response of a mistuned bladed disk, the responses of all blades become different, and the response of a certain blade may become extremely large due to the split of the duplicated eigenvalues, the distortion of the vibration modes, and so on. On the other hand, many researchers suggest that the mistuning suppresses the blade flutter, because the complete travelling wave mode is not formed in a disk. In other words, the main conclusions of researches on mistuning are that while mistuning has an undesirable effect on the forced response, it has a beneficial (stabilizing) effect on the blade flutter (the self-excited vibration). Although such mistuning phenomena of bladed disks have been studied since 1980s, almost all studies focused on the amplification factor of the displacement response, and few studies researched the amplification factor of the vibratory stress response. In this study, first, the frequency response analysis of the mistuned simple bladed disk consisting of flat plates is carried out. Comparing the amplification factor of the displacement response with that of the vibratory stress response, the amplification factor expressed by the vibratory stress is studied in detail. Second, the mistuning analysis of the actual bladed disk used in a steam turbine is carried out. From these results, the mistuning effect expressed by the vibratory stress is clarified.

Study on Transient Vibration of Mistuned Bladed Disk Passing Through Resonance

2013 ◽  
Author(s):  
Yasutomo Kaneko
Keyword(s):  
Vibration Analysis ◽  
Response Analysis ◽  
Analysis Method ◽  
Frequency Response Analysis ◽  
Transient Vibration ◽  
Mass Model ◽  
Bladed Disk ◽  
Acceleration Rate ◽  
Start Up ◽  
Speed Engine

In a variable speed engine, it is impossible to avoid the resonance during operation. In a constant speed engine, the resonance during start-up or shut-down also cannot be avoided. Therefore, the increase of the acceleration rate in passing through the resonance has been considered as one of the effective methods for reducing the vibratory stress of the blade and increasing the reliability of the turbomachinery. In this study, the transient vibration analysis of the mistuned bladed disk passing through the resonance is carried out, using the conventional modal analysis method and the numerical integration method. First, the mistuned bladed disk is modeled by the equivalent spring-mass model, and the steady frequency response analysis is carried out by the Monte Carlo simulation, in order to obtain the worst mistuning pattern. Second, for the mistuned bladed disk of the worst mistuning pattern, the transient vibration analysis in passing through the resonance is carried out, and the effect of the acceleration rate and the blade damping on the transient vibration response is examined in detail. From these results, it is concluded that the larger the acceleration rate is, the smaller the mistuning effect is.

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