Experimental Demonstration of Maximum Mistuned Bladed Disk Forced Response

2003 ◽  
Vol 125 (4) ◽  
pp. 673-681 ◽  
Author(s):  
J. A. Kenyon ◽  
J. H. Griffin
Keyword(s):  
Traveling Wave ◽  
Close Agreement ◽  
Maximum Amplitude ◽  
Forced Response ◽  
Maximum Response ◽  
Experimental Demonstration ◽  
Wave Excitation ◽  
Bladed Disk ◽  
Engine Order ◽  
Structural Mode

A theory was previously developed for predicting robust maximum forced response in mistuned bladed disks from distortion of a structural mode. This paper describes an experiment to demonstrate the theory. A bladed disk is designed to be sufficiently sensitive to mistuning to obtain maximum response. The maximum amplitude magnification from mistuning is predicted using the theory, 1.918. The bladed disk is intentionally mistuned to obtain the maximum response, and the response to an engine order traveling wave excitation is measured. The measured amplitude magnification is in close agreement with the theory. The robustness of the maximum response is demonstrated.

Experimental Demonstration of Maximum Mistuned Bladed Disk Forced Response

2003 ◽  
Author(s):  
J. A. Kenyon ◽  
J. H. Griffin
Keyword(s):  
Traveling Wave ◽  
Close Agreement ◽  
Maximum Amplitude ◽  
Forced Response ◽  
Maximum Response ◽  
Experimental Demonstration ◽  
Wave Excitation ◽  
Bladed Disk ◽  
Engine Order ◽  
Structural Mode

A theory was previously developed for predicting robust maximum forced response in mistuned bladed disks from distortion of a structural mode. This paper describes an experiment to demonstrate the theory. A bladed disk is designed to be sufficiently sensitive to mistuning to obtain maximum response. The maximum amplitude magnification from mistuning is predicted using the theory, 1.918. The bladed disk is intentionally mistuned to obtain the maximum response, and the response to an engine order traveling wave excitation is measured. The measured amplitude magnification is in close agreement with the theory. The robustness of the maximum response is demonstrated.

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.

Maximum Bladed Disk Forced Response From Distortion of a Structural Mode

2003 ◽  
Vol 125 (2) ◽  
pp. 352-363 ◽  
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.

A Test Rig for Noncontact Traveling Wave Excitation of a Bladed Disk With Underplatform Dampers

2010 ◽  
Vol 133 (3) ◽  
Author(s):  
Teresa Berruti ◽  
Christian M. Firrone ◽  
Muzio M. Gola
Keyword(s):  
Traveling Wave ◽  
Numerical Models ◽  
Experimental Tests ◽  
Calibration Procedure ◽  
Forced Response ◽  
Wave Excitation ◽  
Test Rig ◽  
Response Measurement ◽  
Static Test ◽  
Bladed Disk

This paper presents a static test rig called “Octopus” designed for the validation of numerical models aimed at calculating the nonlinear dynamic response of a bladed disk with underplatform dampers (UPDs). The test rig supports a bladed disk on a fixture and each UPD is pressed against the blade platforms by wires pulled by dead weights. Both excitation system and response measurement system are noncontacting. This paper features the design and the setup of the noncontacting excitation generated by electromagnets placed under each blade. A traveling wave excitation is generated according to a desired engine order by shifting the phase of the harmonic force of one electromagnet with respect to the contiguous exciters. Since the friction phenomenon generated by UPDs introduces nonlinearities on the forced response, the amplitude of the exciting force must be kept constant at a known value on every blade during step-sine test to calculate frequency response functions. The issue of the force control is therefore addressed since the performance of the electromagnet changes with frequency. The system calibration procedure and the estimated errors on the generated force are also presented. Examples of experimental tests that can be performed on a dummy integral bladed disk (blisk) mounted on the rig are described in the end.

scholarly journals Experimental Investigation on a Bladed Disk with Traveling Wave Excitation

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 3966
Author(s):  
Luigi Carassale ◽  
Elena Rizzetto
Keyword(s):  
Data Processing ◽  
Traveling Wave ◽  
Frequency Response Function ◽  
Wave Excitation ◽  
Test Rig ◽  
Real Situation ◽  
Bladed Disk ◽  
Experimental Identification ◽  
Alternative Techniques ◽  
Processing Techniques

Bladed disks are key components of turbomachines and their dynamic behavior is strongly conditioned by their small accidental lack of symmetry referred to as blade mistuning. The experimental identification of mistuned disks is complicated due to several reasons related both to measurement and data processing issues. This paper describes the realization of a test rig designed to investigate the behavior of mistuned disks and develop or validate data processing techniques for system identification. To simplify experiments, using the opposite than in the real situation, the disk is fixed, while the excitation is rotating. The response measured during an experiment carried out in the resonance-crossing condition is used to compare three alternative techniques to estimate the frequency-response function of the disk.

Analysis of mistuned forced response in an axial high-pressure compressor rig with focus on Tyler–Sofrin modes

2019 ◽  
Vol 123 (1261) ◽  
pp. 356-377
Author(s):  
F. Figaschewsky ◽  
A. Kühhorn ◽  
B. Beirow ◽  
T. Giersch ◽  
S. Schrape
Keyword(s):  
Axial Compressor ◽  
Maximum Amplitude ◽  
Forced Response ◽  
Operating Conditions ◽  
Cfd Simulations ◽  
High Pressure Compressor ◽  
Engine Order ◽  
Stator Vane ◽  
Vibration Responses ◽  
The Impact

ABSTRACTThis paper aims at contributing to a better understanding of the effect of Tyler–Sofrin Modes (TSMs) on forced vibration responses by analysing a 4.5-stage research axial compressor rig. The first part starts with a brief review of the involved physical mechanisms and necessary prerequisites for the generation of TSMs in multistage engines. This review is supported by unsteady CFD simulations of a quasi 2D section of the studied engine. It is shown that the amplitude increasing effect due to mistuning can be further amplified by the presence of TSMs. Furthermore, the sensitivity with respect to the structural coupling of the blades and the damping as well as the shape of the expected envelope is analysed.The second part deals with the Rotor 2 blisk of the research compressor rig. The resonance of a higher blade mode with the engine order of the upstream stator is studied in two different flow conditions realised by different variable stator vane (VSV) schedules which allows to separate the influence of TSMs from the impact of mistuning. A subset of nominal system modes representation of the rotor is used to describe its mistuned vibration behaviour, and unsteady CFD simulations are used to characterise the present strength of the TSMs in the particular operating conditions. Measured maximum amplitude vs blade pattern and frequency response functions are compared against the predictions of the aeromechanical models in order to assess the strength of the TSMs as well as its influence on vibration levels.

Experimental Investigation of Mode Localization and Forced Response Amplitude Magnification for a Mistuned Bladed Disk

2000 ◽  
Author(s):  
John Judge ◽  
Christophe Pierre ◽  
Oral Mehmed
Keyword(s):  
Experimental Investigation ◽  
Traveling Wave ◽  
Forced Response ◽  
Response Amplitude ◽  
Mode Shapes ◽  
Bladed Disks ◽  
Element Analysis ◽  
Mode Localization ◽  
Bladed Disk ◽  
Out Of Plane

The results of an experimental investigation on the effects of random blade mistuning on the forced dynamic response of bladed disks are reported. The primary aim of the experiment is to gain understanding of the phenomena of mode localization and forced response blade amplitude magnification in bladed disks. A stationary, nominally periodic, twelve-bladed disk with simple geometry is subjected to a traveling-wave, out-of-plane, “engine order” excitation delivered via phase-shifted control signals sent to piezo-electric actuators mounted on the blades. The bladed disk is then mistuned by the addition of small, unequal weights to the blade tips, and it is again subjected to a traveling wave excitation. The experimental data is used to verify analytical predictions about the occurrence of localized mode shapes, increases in forced response amplitude, and changes in resonant frequency due to the presence of mistuning. Very good agreement between experimental measurements and finite element analysis is obtained. The out-of-plane response is compared and contrasted with the previously reported in-plane mode localization behavior of the same test specimen. This work also represents an important extension of previous experimental study by investigating a frequency regime in which modal density is lower but disk-blade interaction is significantly greater.

System Identification of Mistuned Bladed Disks From Traveling Wave Response Measurements

2003 ◽  
Author(s):  
D. M. Feiner ◽  
J. H. Griffin ◽  
K. W. Jones ◽  
J. A. Kenyon ◽  
O. Mehmed ◽  
...  
Keyword(s):  
System Identification ◽  
Modal Analysis ◽  
Traveling Wave ◽  
Natural Frequencies ◽  
Wave Excitation ◽  
New Approach ◽  
Operational Conditions ◽  
System Identification Method ◽  
Bladed Disk ◽  
Identification Method

A new approach to modal analysis is presented that allows the modes and natural frequencies of a mistuned bladed disk to be determined from its response to a traveling wave excitation. The resulting modes and natural frequencies are then used as input to a system identification method to determine the bladed disk’s mistuning while it is rotating. This capability is useful since it provides a basis for determining blade frequencies under engine operational conditions and could help monitor the health of the engine.

scholarly journals An Experimental Investigation of Vibration Localization in Bladed Disks: Part II — Forced Response

1997 ◽  
Author(s):  
Marlin J. Kruse ◽  
Christophe Pierre
Keyword(s):  
Experimental Investigation ◽  
Forced Response ◽  
Mode Shapes ◽  
Bladed Disks ◽  
Structural Coupling ◽  
Vibration Localization ◽  
Bladed Disk ◽  
Engine Order ◽  
Localized Mode ◽  
The Impact

The results of an experimental investigation on the effects of random blade mistuning on the forced dynamic response of bladed disks are reported. Two experimental specimens are considered: a nominally periodic twelve-bladed disk with equal blade lengths, and the corresponding mistuned bladed disk, which features slightly different blades of random lengths. Both specimens are subject to traveling-wave excitations delivered by piezo-electric actuators. The primary aim of the experiment is to demonstrate the occurrence of an increase in forced response blade amplitudes due to mistuning, and to verify analytical predictions about the magnitude of these increases. In particular, the impact of localized mode shapes, engine order excitation, and disk structural coupling on the sensitivity of forced response amplitudes to blade mistuning is reported. This work reports one of the first systematic experiments carried out to demonstrate and quantify the effect of mistuning on the forced response of bladed disks.

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.

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