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.

Piezoelectric Networks for Vibration Suppression of Mistuned Bladed Disks

Aerospace ◽  
2006 ◽  
Author(s):  
Hongbao Yu ◽  
K. W. Wang
Keyword(s):  
Vibration Suppression ◽  
Periodic Structures ◽  
Electric Circuit ◽  
Forced Response ◽  
Bladed Disks ◽  
Vibration Localization ◽  
Bladed Disk ◽  
Engine Order ◽  
The Individual ◽  
Local Circuits

Extensive investigations have been conducted to study the vibration localization phenomenon and the excessive forced response that can be caused by mistuning in bladed disks. Most previous researches have focused on attacking the mistuning issue in the bladed disk, such as reducing the sensitivity of the structure to mistuning through mechanical tailoring, or design optimization. Few have focused on developing effective vibration control methods for such systems. This study extends the piezoelectric network concept, which has been utilized for mode delocalization in periodic structures, to the control of mistuned bladed disks under engine order excitation. A piezoelectric network is synthesized and optimized to effectively suppress the excessive vibration in the bladed disk caused by mistuning. One of the merits of such an approach is that the optimum design is independent of the number of spatial harmonics, or engine orders. Local circuits are first formulated by connecting inductors and resistors with piezoelectric patches on the individual blades. While these local circuits can function as conventional damped absorber when properly tuned, they do not perform well for bladed disks under all engine order excitations. To address this issue, capacitors are introduced to couple the individual local circuitries. Through such networking, an absorber system that is independent of the engine order can be achieved. Monte Carlo simulation is performed to investigate the effectiveness of the network for bladed disk with a range of mistuning level of its mechanical properties. The robustness issue of the network in terms of detuning of the electric circuit parameters is also studied. Finally, negative capacitance is introduced and its effect on the robustness of the network is investigated.

On the Individual and Combined Effects of Intentional Mistuning, Coupling and Damping on the Forced Response of Bladed Disks

2008 ◽  
Author(s):  
Changbo Yu ◽  
Jianjun Wang ◽  
Qihan Li
Keyword(s):  
High Cycle Fatigue ◽  
Numerical Study ◽  
Threshold Value ◽  
Forced Response ◽  
Combined Effects ◽  
Bladed Disks ◽  
Disk Model ◽  
Bladed Disk ◽  
Random Mistuning ◽  
The Individual

Random mistuning always exists in bladed disk structures. The maximum blade forced response amplitudes are often much larger than those of their perfectly tuned counterparts, which leads to eventual failure via high cycle fatigue (HCF). Therefore, it is of great importance to predict and, ultimately, to reduce the blade forced response levels as a result of random mistuning. In this paper, intentional mistuning is introduced into a simplified 12-bladed disk model by varying the stiffness of the blades in periodic harmonic patterns. The individual and combined effects of intentional mistuning, coupling and damping are examined in the absence and presence of random mistuning through numerical study. It is found that there is some threshold value of intentional mistuning and coupling that leads to maximum mistuning effects and certain relations among intentional mistuning strength, integer harmonics, coupling and damping can suppress the response levels of mistuned bladed disks, which provides useful guidelines for safe and reliable designs of bladed disk systems.

Topological Optimization of Piezoelectric Transducers for Vibration Reduction of Bladed Disks

2021 ◽  
Author(s):  
Y. Fan ◽  
H. Y. Ma ◽  
Y. G. Wu ◽  
L. Li ◽  
K. Y. Tian ◽  
...  
Keyword(s):  
Electromechanical Coupling ◽  
Piezoelectric Materials ◽  
Damping Ratio ◽  
Added Mass ◽  
Topological Optimization ◽  
Fe Model ◽  
Bladed Disks ◽  
Multiple Modes ◽  
Bladed Disk ◽  
Modal Damping

Abstract In this work, we develop a numerical method to determine the best distribution of piezoelectric materials on a given bladed disk, so as to minimize the added mass of shunted piezoelectric dampers. There is no constrain on the shape of piezoelectric materials, and only the overall mass is limited. The method can be applied to a single mode or several modes from the same or different modal groups. The method is based on the fact that the modal damping is solely determined by the modal electromechanical coupling factor (MEMCF) which is related to the modal stress field and the geometric of the piezoelectric materials only. A linear weighting of stress components is proposed as the criterion to determine the priority of locations for piezoelectric materials. The piezoelectric materials are introduced to the FE model by modifying the type and materials parameters of elements if they are embedded to the bladed disks; or by creating an additional layers of elements if they are bonded to the bladed disks. Details for considering multiple modes, handling polarization direction and electrode connection are also presented. The proposed procedure is applied to an empirical bladed disk with NASA-ROTOR37 profile. Results show that 12% damping ratio can be achieved for multiple modes simultaneously, if we locate piezoelectric materials on the blade with 10% added mass. When locate the piezoelectric materials on the disk and the added mass is only 5%, up to 13% modal damping ratio for the disk dominant modes can be achieved.

Study on Vibration Response Characteristics of Mistuned Bladed Disk Expressed by Vibratory Stress

2019 ◽  
Author(s):  
Yasutomu Kaneko ◽  
Toshio Watanabe ◽  
Tatsuya Furukawa ◽  
Saiji Washio
Keyword(s):  
Amplification Factor ◽  
Harmonic Excitation ◽  
Forced Response ◽  
Von Mises Stress ◽  
Bladed Disks ◽  
Resonant Amplitude ◽  
Response Characteristics ◽  
Bladed Disk ◽  
Disk Structure ◽  
Von Mises

Abstract Although bladed disks of turbomachinery are nominally designed to be cyclically symmetric (tuned system), the vibration characteristics of individual blades on a disk differ slightly owing to manufacturing tolerance, deviation of material properties, wear during operation, etc. These small variations break cyclic symmetry and split eigenvalue pairs. Actual bladed disks with small variations are called mistuned systems. Many researchers have studied mistuning and the main conclusion is that while mistuning has an undesirable effect on forced response, it has a beneficial effect on blade flutter. Although mistuning phenomena have been studied since the 1980s, studies on forced response are mostly related to increase in the resonant amplitude due to harmonic excitation force. In addition, because few papers have treated the amplification factor expressed in terms of vibratory stress, the mistuning phenomena of bladed disks expressed in terms of vibratory stress are not fully understood. In this study, the mistuning effect expressed in terms of vibratory stress is examined using the reduced-order model SNM (Subset of Nominal Modes) without any assumptions. By comparing the amplification factor expressed in terms of displacement response with that expressed in terms of vibratory stress response, including synthesized stress (von Mises stress and principal stress), the mistuning phenomena expressed in terms of vibratory stress are clarified. The effect of bladed disk structure on amplification factor is examined in detail as well.

Investigation of Coriolis Effect on Vibration Characteristics of a Realistic Mistuned Bladed Disk

2011 ◽  
Author(s):  
Jianqiang Xin ◽  
Jianjun Wang
Keyword(s):  
Coriolis Force ◽  
Vibration Characteristics ◽  
Bladed Disks ◽  
Disk Model ◽  
Coriolis Forces ◽  
Response Characteristics ◽  
Bladed Disk ◽  
Damping Matrix ◽  
Disk Rotation ◽  
Speed Effect

Mistuning, which refers to inevitable variations in blades properties, will change the vibration of bladed disks dramatically. Bladed disks are exposed to effects of forces caused by bladed disk rotation, such as centrifugal and Coriolis forces. However, there is little research on the vibration behavior of a realistic bladed disk with Coriolis force. An investigation of the speed effect, i.e., the effects of centrifugal and Coriolis forces, on the vibration characteristics of a realistic mistuned bladed disk model is presented in this paper. Finite element method (FEM) is used to obtain the system mass, stiffness and damping matrix. The effects of Coriolis force and centrifugal force on the modal frequency and harmonic response characteristics of tuned bladed disk are investigated first, then the modal localization and response characteristics of mistuned bladed disk are researched. This investigation indicates that: Coriolis force has efficient influences on the modal and response characteristics of a realistic mistuned bladed disk: it can both increase and decrease the localization of the mistuned bladed disk for different situations.

Piezoelectric Networks for Vibration Suppression of Mistuned Bladed Disks

2007 ◽  
Vol 129 (5) ◽  
pp. 559-566 ◽  
Author(s):  
Hongbiao Yu ◽  
K. W. Wang
Keyword(s):  
Vibration Suppression ◽  
Periodic Structures ◽  
Electric Circuit ◽  
Forced Response ◽  
Bladed Disks ◽  
Vibration Localization ◽  
Network Concept ◽  
Engine Order ◽  
The Individual ◽  
Local Circuits

Extensive investigations have been conducted to study the vibration localization phenomenon and the excessive forced response that can be caused by mistuning in bladed disks. Most previous researches have focused on analyzing∕predicting localization or attacking the mistuning issue via mechanical tailoring. Few have focused on developing effective vibration control methods for such systems. This study extends the piezoelectric network concept, which has been utilized for mode delocalization in periodic structures, to the control of mistuned bladed disks under engine order excitation. A piezoelectric network is synthesized and optimized to effectively suppress vibration in bladed disks. One of the merits of such an approach is that the optimum design is independent of the number of spatial harmonics, or engine orders. Local circuits are first formulated by connecting inductors and resistors with piezoelectric patches on the individual blades. Although these local circuits can function as conventional damped absorber when properly tuned, they do not perform well for bladed disks under all engine order excitations. To address this issue, capacitors are introduced to couple the individual local circuitries. Through such networking, an absorber system that is independent of the engine order can be achieved. Monte Carlo simulation is performed to investigate the effectiveness of the network for a bladed disk with a range of mistuning level of its mechanical properties. The robustness issue of the network in terms of detuning of the electric circuit parameters is also studied. Finally, negative capacitance is introduced and its effect on the performance and robustness of the network is investigated.

Vibration Suppression of Mistuned Coupled-Blade-Disk Systems Using Piezoelectric Circuitry Network

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Hongbiao Yu ◽  
K. W. Wang
Keyword(s):  
Piezoelectric Transducer ◽  
Vibration Suppression ◽  
Structural Vibration ◽  
Bladed Disks ◽  
Disk Model ◽  
Bladed Disk ◽  
Engine Order ◽  
Optimal Network ◽  
Random Mistuning ◽  
Engine Components

For bladed-disk assemblies in turbomachinery, the elements are often exposed to aerodynamic loadings, the so-called engine order excitations. It has been reported that such excitations could cause significant structural vibration. The vibration level could become even more excessive when the bladed disk is mistuned, and may cause fatigue damage to the engine components. To effectively suppress vibration in bladed disks, a piezoelectric transducer networking concept has been explored previously by the authors. While promising, the idea was developed based on a simplified bladed-disk model without considering the disk dynamics. To advance the state of the art, this research further extends the investigation with focus on new circuitry designs for a more sophisticated and realistic system model with the consideration of coupled-blade-disk dynamics. A novel multicircuit piezoelectric transducer network is synthesized and analyzed for multiple-harmonic vibration suppression of bladed disks. An optimal network is derived analytically. The performance of the network for bladed disks with random mistuning is examined through Monte Carlo simulation. The effects of variations (mistuning and detuning) in circuit parameters are also studied. A method to improve the system performance and robustness utilizing negative capacitance is discussed. Finally, experiments are carried out to demonstrate the vibration suppression capability of the proposed piezoelectric circuitry network.

scholarly journals High-Fidelity Sensitivity Analysis of Modal Properties of Mistuned Bladed Disks Regarding Material Anisotropy

2018 ◽  
Author(s):  
Adam Koscso ◽  
Guido Dhondt ◽  
E. P. Petrov
Keyword(s):  
Sensitivity Analysis ◽  
Finite Element ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Finite Element Models ◽  
Coordinate Systems ◽  
Bladed Disks ◽  
Bladed Disk ◽  
Material Orientation

A new method has been developed for sensitivity calculations of modal characteristics of bladed disks made of anisotropic materials. The method allows the determination of the sensitivity of the natural frequencies and mode shapes of mistuned bladed disks with respect to anisotropy angles that define the crystal orientation of the monocrystalline blades using full-scale finite element models. An enhanced method is proposed to provide high accuracy for the sensitivity analysis of mode shapes. An approach has also been developed for transforming the modal sensitivities to coordinate systems used in industry for description of the blade anisotropy orientations. The capabilities of the developed methods are demonstrated on examples of a single blade and a mistuned realistic bladed disk finite element models. The modal sensitivity of mistuned bladed disks to anisotropic material orientation is thoroughly studied.

scholarly journals Investigations of dynamic characteristics of a tall industrial chimney due to light wind and solar radiation

2013 ◽  
Vol 12 (2) ◽  
pp. 087-094 ◽  
Author(s):  
Peter Breuer ◽  
Tadeusz Chmielewski ◽  
Piotr Górski ◽  
Eduard Konopka ◽  
Lesław Tarczyński
Keyword(s):  
Solar Radiation ◽  
Dynamic Characteristics ◽  
Field Tests ◽  
Power Station ◽  
Temperature Variations ◽  
Response Characteristics ◽  
Modal Damping ◽  
Wind Response ◽  
Satellite Signal ◽  
Air Temperature Variations

The present paper describes field tests conducted on the 300 m tall industrial chimney, located in the power station of Bełchatów (Poland), where the GPS rover receivers were installed at three various levels. The objectives of these GPS tests were to investigate the deformed vertical profile of this chimney, and its dynamic characteristics, i.e. the first natural frequency and the modal damping ratios. The results for the satellite signal receptions, the synopsis of recorded baselines and their ambiguity solutions, drifts of the chimney due to solar radiation and air temperature variations and dynamic wind response characteristics are presented.

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