Numerical Investigations of Localized Vibrations of Mistuned Blade Integrated Disks (Blisks)

Klauke, Thomas; Kühhorn, Arnold; Beirow, Bernd; Golze, Mark

doi:10.1115/1.2985074

Cited by 20 publications

(13 citation statements)

References 28 publications

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“…The black dots in Fig. 2 are mixed modes (13) , with a clearly higher contribution of the disk motion and hence a smaller level of strain energy in the blades.…”

Section: Basic Vibration Analysesmentioning

confidence: 99%

Model update and validation of a mistuned high-pressure compressor blisk

et al. 2019

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In order to prepare an advanced 4-stage high-pressure compressor rig test campaign, details regarding both accomplishment and analysis of preliminary experiments are provided in this paper. The superior objective of the research project is to contribute to a reliable but simultaneously less conservative design of future high pressure blade integrated disks (blisk). It is planned to achieve trend-setting advances based on a close combination of both numerical and experimental analyses. The analyses are focused on the second rotor of this research compressor, which is the only one being manufactured as blisk. The comprehensive test program is addressing both surge and forced response analyses e.g. caused by low engine order excitation. Among others the interaction of aeroelastics and blade mistuning is demanding attention in this regard. That is why structural models are needed, allowing for an accurate forced response prediction close to reality. Furthermore, these models are required to support the assessment of blade tip timing (BTT) data gathered in the rig tests and strain gauge (s/g) data as well. To gain the maximum information regarding the correlation between BTT data, s/g-data and pressure gauge data, every blade of the second stage rotor (28 blades) is applied with s/g. However, it is well known that s/g on blades can contribute additional mistuning that had to be considered upon updating structural models.Due to the relevance of mistuning, efforts are made for its accurate experimental determination. Blade-by-blade impact tests according to a patented approach are used for this purpose. From the research point of view, it is most interesting to determine both the effect s/g-instrumentation and assembling the compressor stages on blade frequency mistuning. That is why experimental mistuning tests carried out immediately after manufacturing the blisk are repeated twice, namely, after s/g instrumentation and after assembling. To complete the pre-test program, the pure mechanical damping and modal damping ratios dependent on the ambient pressure are experimentally determined inside a pressure vessel. Subsequently the mistuning data gained before is used for updating subset of nominal system mode (SNM) models. Aerodynamic influence coefficients (AICs) are implemented to take aeroelastic interaction into account for forced response analyses. Within a comparison of different models, it is shown for the fundamental flap mode (1F) that the s/g instrumentation significantly affects the forced response, whereas the impact of assembling the compressor plays a minor role.

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“…The black dots in Fig. 2 are mixed modes (13) , with a clearly higher contribution of the disk motion and hence a smaller level of strain energy in the blades.…”

Section: Basic Vibration Analysesmentioning

confidence: 99%

Model update and validation of a mistuned high-pressure compressor blisk

et al. 2019

Self Cite

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“…Combining Fig. 2 and Table 1, the vibration mode of the academic blisk can be divided into two types according to the blade's contribution to total blisk strain energy: blade-dominated and disk-dominated (Klauke et al, 2009). The first 10 orders' natural frequencies are approximately close in the interval [598.49 Hz,644.64 Hz] and the vibration mode are blade-dominated, which can be distinguished by the number of nodal diameter (ND) and circle (NC) lines.…”

Section: Natural Characteristicsmentioning

confidence: 99%

Prediction of vibration characteristics of blisks using similitude models

Zhang

Wang

Zhai

et al. 2019

Mechanics Based Design of Structures and Machines

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This study investigates the determination approach of distorted scaling laws for predicting the dynamic characteristic of an aero engine's blisk. Based on the dynamic scaling laws of typical thin-walled structures, an assumption of geometrically complete scaling laws is firstly proposed and numerically validated. For distorted models of disk thickness, in order to simplify the design procedure, a simplification condition is proposed and applied to the first 10 orders' distorted scaling laws (blade-dominated vibrations) by combining sensitivity analysis. Next, the 11th-14th orders' distorted scaling laws are determined for disk-dominated vibrations. Numerical validation demonstrates that distorted scaling laws possess a good accuracy. Finally, the applicability of these new scaling laws is validated by the experimental data. The results indicate that, by using the new scaling laws, the simple models can predict vibration characteristics of blisk by employing similitude models.

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“…Mistuning Implementation Small mistuning is implemented through material properties variations, thus echoing with tolerances formulation of industrial manufacturing processes. As blade mistuning has been shown to be critically dominant [16,1], mistuning is here considered as a blade Young's modulus variation for each blade i:…”

Section: Numerical Solutionmentioning

confidence: 99%

Numerical Investigation of an Academic Mistuned Bladed Disk Dynamics Accounting for Blade/Casing Contacts

Joachim

Nyssen

Batailly

2019

Volume 4: Dynamics, Vibration, and Control

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This contribution focuses on the combined analysis of mistuning and unilateral blade-tip/casing contacts. A 2D phenomenological finite element model of an aircraft engine fan stage is considered. It is reduced by means of the Craig-Bampton component mode synthesis method and contact treatment relies on a Lagrange multiplier algorithm within an explicit time-integration scheme. Blade-tip/casing contacts are initiated through the deformed shape of a perfectly rigid casing. Mistuning is accounted for on the blades only. Monte Carlo simulations are carried out in both linear and nonlinear configurations, which allows to compare amplifications predicted in both context due to mistuning. Following a thorough convergence analysis of the proposed numerical strategy, the influence of mistuning level as well as the configuration of the external forcing are investigated. Presented results underline the detrimental consequences of mistuning in a nonlinear structural context, yielding even higher vibration amplifications than in a linear context. A cross-analysis between linear and nonlinear computations reveals that no correlation is found between linear and nonlinear amplifications which suggests that the effect of existing strategies to mitigate vibration amplifications within a linear context may not be suitable within a nonlinear context.

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Numerical Investigations of Localized Vibrations of Mistuned Blade Integrated Disks (Blisks)

Cited by 20 publications

References 28 publications

Model update and validation of a mistuned high-pressure compressor blisk

Model update and validation of a mistuned high-pressure compressor blisk

Prediction of vibration characteristics of blisks using similitude models

Numerical Investigation of an Academic Mistuned Bladed Disk Dynamics Accounting for Blade/Casing Contacts

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