Flutter and Response of a Mistuned Cascade in Incompressible Flow

Kaza, K. R. V.; Kielb, Robert E.

doi:10.2514/3.51172

Cited by 128 publications

(36 citation statements)

References 6 publications

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“…(1) and (2), each blade is modeled as a two degree of freedom oscillator in which the plunging and pitching motions are inertially coupled (see The other nondimensional variables are defined in the nomenclature and described in Ref. (1). Writing these equations for all blades and arranging then in matrix form results in…”

Section: Theorymentioning

confidence: 99%

Effects of Structural Coupling on Mistuned Cascade Flutter and Response

Kielb

Kaza

1984

Journal of Engineering for Gas Turbines and Power

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The effects of structural coupling on mistuned cascade flutter and response are analytically investigated using an extended typical section model. Previous work using two degree of freedom per blade typical section models has included only aerodynamic coupling. The present work extends this model to include both structural and aerodynamic coupling between the blades. The model assumes that the structurally coupled system natural modes have been determined and can be represented in the form of N bending and N torsional uncoupled modes for each blade, where N is the number of blades and, hence, is only valid for blade dominated motion. The aerodynamic loads are calculated by using two-dimensional unsteady cascade theories in the subsonic and supersonic flow regimes. The results show that the addition of structural coupling can affect both the aeroelastic stability and frequency. The stability is significantly affected only when the system is mistuned. The resonant frequencies can be significantly changed by structural coupling in both tuned and mistuned systems, however, the peak response is significantly affected only in the latter.

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Section: Theorymentioning

confidence: 99%

Effects of Structural Coupling on Mistuned Cascade Flutter and Response

Kielb

Kaza

1984

Journal of Engineering for Gas Turbines and Power

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“…For example, all of the blades in a spinning fan or bladed disc are nominally identical, and so there exists a discrete circumferential symmetry. It has been noted numerically [3][4][5] and experimentally 6 that if we mistune these blades by making them different from one another, then the utter boundary can be delayed dramatically. Techniques presented herein restrict attention to circumferential symmetry breaking but apply to any type of instability.…”

mentioning

confidence: 99%

Symmetry Approach to Extension of Flutter Boundaries via Mistuning

Shapiro

1998

Journal of Propulsion and Power

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A general framework is presented for analyzing and optimizing stability increases resulting from mistuning. The framework given is model independent and is based primarily on symmetry arguments. Dif cult practical issues are transformed to tractable mathematical questions. It is shown that mistuning analysis reduces to a block circular matrix eigenvalue /vector problem that can be solved ef ciently even for large problems. Similarly, the optimization becomes a standard linear constraint quadratic programming problem and can be solved numerically. Because the methods given are model-independent, they can be applied to various models and allow the researcher to easily conclude which models accurately capture mistuning and which do not. A simple quasisteady model for utter in a cascade is used to illustrate and validate results in this paper.Nomenclature a = linear stability coef cient, Eqs. (13), (14), and (35) b = diagonal quadratic stability coef cient, Eqs. (13), (14), and (36) c i = ith off-diagonal quadratic stability coef cient, Eqs.

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“…The vibration of mistuned bladed disks with both structural and aerodynamic coupling has been examined using relatively simple models in several previous studies [50][51][52][53][54][55]. However, recently developed reduced-order modeling methods provide a new opportunity to investigate this issue more thoroughly.…”

Section: Aeroelastic Modeling Of Mistuned Bladed Disksmentioning

confidence: 99%

Next-Generation Modeling, Analysis, and Testing of the Vibration of Mistuned Bladed Disks

Castanier¹,

Ceccio²,

Epureanu³

et al. 2007

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Public reporting burden for this collection of infonmation is estimated to average 1 hour per response, including the time for revievong instructions, searching eXisting data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, Including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for falling to comply with a collection of information id it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYV)2 SPONSORING I MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR'S ACRONYM(S)Air Force DISTRIBUTION I AVAILABILITY STATEMENTApproved for public release; distribution is unlimited. AFRL-SR-AR-TR_080011 SUPPLEMENTARY NOTES ABSTRACTTurbomachinery rotors, or bladed disks, are known to suffer from severe vibration problems due to small, random deviations (mistuning) of the blade properties. Mistuning can lead to dramatic increases in the maximum blade stress and cause high cycle fatigue (HCF), which is a major cost, readiness, and safety concern for the U.S. Air Force. The primary objective of this research was to provide significantly improved understanding, modeling, and prediction of the vibration response of mistuned bladed disk systems by including the effects of important phenomena that had been largely neglected in previous mistuning models. The models developed in this research program were used to investigate the interaction of blade mistuning with aerodynamic coupling, stage-to-stage connections for multistage rotors, blade damage, and nonlinearities. In addition, key mistuning phenomena were examined through vibration testing of blisks (single-piece bladed disks). New methods were developed for identifying blade mistuning parameters from test data and for running experimental Monte Carlo assessments of the effects of mistuning on the system forced response. SUBJECT TERMS AbstractTurbomachinery rotors, or bladed disks, are known to suffer from severe vibration problems due to small, random deviations (mistuning) of the blade properties. Mistuning can lead to dramatic increases in the maximum blade stress and cause high cycle fatigue (HCF), which is a major cost, readiness, and safety concern for the U.S. Air Force. The primary objective of this research was to provide significantly improved understanding, modeling, and prediction of the vibration response of mistuned bladed disk systems by including the effects of important phenomena that had been largely neglected in previous mistuning models. The models developed in this research program were used to investigate the int...

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Flutter and Response of a Mistuned Cascade in Incompressible Flow

Cited by 128 publications

References 6 publications

Effects of Structural Coupling on Mistuned Cascade Flutter and Response

Effects of Structural Coupling on Mistuned Cascade Flutter and Response

Symmetry Approach to Extension of Flutter Boundaries via Mistuning

Next-Generation Modeling, Analysis, and Testing of the Vibration of Mistuned Bladed Disks

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