Numerical and Experimental Investigation of an Underplatform Damper Test Rig

Pesaresi, Luca; Salles, Loïc; Elliott, Robert C.; Jones, A.H.; Green, J.S.; Schwingshackl, Christoph W.

doi:10.4028/www.scientific.net/amm.849.1

Cited by 20 publications

(23 citation statements)

References 31 publications

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“…The excitation is provided by an electrodynamic shaker, attached below the platform, and the response is measured with two non-contact laser doppler vibrometers (LDV) focused 20 mm below the tip of each blade. A more detailed discussion of the rig development, and an initial assessment of its capabilities can be found in [33]. …”

Section: Design Features and Set-upmentioning

confidence: 99%

“…The underplatform damper test rig developed for this study is an experimental set up that allows the effect of UPDs on blade-like structures to be evaluated [33]. Following a review of similar test rigs [6,11,31,32], a static rig design was chosen in order to minimise the effect of mistuning on the response, as well as allow better control of the experimental set up, and simplify the testing procedure.…”

Section: Rig Concept and Non-dimensional Parametersmentioning

confidence: 99%

“…In a real engine, the inter blade phase angle (phase between two consecutive blades) will be between these two extreme values depending on the nodal diameter excited, so that the test rig covers the boundaries of the operational range of the damper. The damper was always loaded with a constant high load of 960 N to ensure a good conformity at the contact interface, since an initial convergence study showed strong joint variability at lower damper loads [33]. A stepped sine test with a Data Physics SignalCalc ACE card was performed around each resonance at various levels of excitation, from 0.01 N to 17 N, leading to a CF /F exc ratio from 10k to 56.…”

Section: Nonlinear Experimental Frfs and Damper Kinematicsmentioning

confidence: 99%

See 2 more Smart Citations

Modelling the nonlinear behaviour of an underplatform damper test rig for turbine applications

Pesaresi

Salles

Jones

et al. 2017

Mechanical Systems and Signal Processing

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145

108

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Underplatform dampers (UPD) are commonly used in aircraft engines to mitigate the risk of high-cycle fatigue failure of turbine blades. The energy dissipated at the friction contact interface of the damper reduces the vibration amplitude significantly, and the couplings of the blades can also lead to significant shifts of the resonance frequencies of the bladed disk. The highly nonlinear behaviour of bladed disks constrained by UPDs requires an advanced modelling approach to ensure that the correct damper geometry is selected during the design of the turbine, and that no unexpected resonance frequencies and amplitudes will occur in operation. Approaches based on an explicit model of the damper in combination with multi-harmonic balance solvers have emerged as a promising way to predict the nonlinear behaviour of UPDs correctly, however rigorous experimental validations are required before approaches of this type can be used with confidence.In this study, a nonlinear analysis based on an updated explicit damper model having different levels of detail is performed, and the results are evaluated against a newly-developed UPD test rig. Detailed linear finite element models are used as input for the nonlinear analysis, allowing the inclusion of damper flexibility and inertia effects. The nonlinear friction interface between the blades and the damper is described with a dense grid of 3D friction contact elements which allow accurate capturing of the underlying nonlinear mechanism that drives the global nonlinear behaviour. The introduced explicit damper model showed a great dependence on the correct contact pressure distribution. The use of an accurate, measurement based, distribution, better matched the nonlinear dynamic behaviour of the test rig. Good agreement with the measured frequency response data could only be reached when the zero harmonic term (constant term) was included in the multi-harmonic expansion of the nonlinear problem, highlighting its importance when the contact interface experiences large normal load variation. The resulting numerical damper kinematics with strong translational and rotational motion, and the global blades frequency response were fully validated experimentally, showing the accuracy of the suggested high detailed explicit UPD modelling approach.

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Section: Design Features and Set-upmentioning

confidence: 99%

Section: Rig Concept and Non-dimensional Parametersmentioning

confidence: 99%

Section: Nonlinear Experimental Frfs and Damper Kinematicsmentioning

confidence: 99%

See 1 more Smart Citation

Modelling the nonlinear behaviour of an underplatform damper test rig for turbine applications

Pesaresi

Salles

Jones

et al. 2017

Mechanical Systems and Signal Processing

Self Cite

145

108

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show abstract

“…Past experience indicates that significant wear can occur at the damper during operation, but its impact on the bladed-disk dynamics is normally neglected. A simplified blade-damper geometry of a recentlydeveloped underplatform damper test rig [26] will be used to demonstrate the change in the nonlinear dynamic response due to damper wear.…”

Section: The Underplatform Damper Test Casementioning

confidence: 99%

A Multiscale Approach for Nonlinear Dynamic Response Predictions With Fretting Wear

Armand

Pesaresi

Salles

et al. 2016

Journal of Engineering for Gas Turbines and Power

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Accurate prediction of the vibration response of aircraft engine assemblies is of great importance when estimating both the performance and the lifetime of their individual components. In the case of underplatform dampers, for example, the motion at the frictional interfaces can lead to a highly nonlinear dynamic response and cause fretting wear at the contact. The latter will change the contact conditions of the interface and consequently impact the nonlinear dynamic response of the entire assembly. Accurate prediction of the nonlinear dynamic response over the lifetime of the assembly must include the impact of fretting wear. A multi-scale approach that incorporates wear into the nonlinear dynamic analysis is proposed, and its viability is demonstrated for an underplatform damper system. The nonlinear dynamic response is calculated with a multiharmonic balance approach, and a newly developed semi-analytical contact solver is used to obtain the contact conditions at the blade-damper interface with high accuracy and low computational cost. The calculated contact conditions are used in combination with the energy wear approach to compute the fretting wear at the contact interface. The nonlinear dynamic model of the blade-damper system is then updated with the worn profile and its dynamic response is recomputed. A significant impact of fretting wear on the nonlinear dynamic behaviour of the blade-damper system was observed, highlighting the sensitivity of the nonlinear dynamic response to changes at the contact interface. The computational speed and robustness of the adopted multi-scale approach are demonstrated.

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“…An FE modal analysis was described and a simplified method to evaluate the under-platform damper effects was also presented by Bessone and Traversone [30]. Based on a set of newly introduced non-dimensional parameters that ensured a similar dynamic behavior of the test rig to a real turbine blade-damper system, a new experimental damper rig was developed [31].…”

Section: Introductionmentioning

confidence: 99%

Dynamic Response of a Simplified Turbine Blade Model with Under-Platform Dry Friction Dampers Considering Normal Load Variation

Ouyang

Ren

et al. 2017

Applied Sciences

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Dry friction dampers are widely used to reduce vibration. The forced vibration response of a simplified turbine blade with a new kind of under-platform dry friction dampers is studied in this paper. The model consists of a clamped blade as two rigidly connected beams and two dampers in the form of masses which are allowed to slide along the blade platform in the horizontal direction and vibrate with the blade platform in the vertical direction. The horizontal and vertical vibrations of the two dampers, and the horizontal and transverse platform vibrations are coupled by friction at the contact interfaces which is assumed to follow the classical discontinuous Coulomb's law of friction. The vertical motion of the dampers leads to time-varying contact forces and can cause horizontal stick-slip motion between the contact surfaces. Due to the relative horizontal motion between the dampers and the blade platform, the vertical contact forces and the resultant friction forces act as moving loads. The Finite Element (FE) method and Modal Superposition (MS) method are applied to solve the dynamic response, together with an algorithm that can capture nonsmooth transitions from stick to slip and slip to stick. Quasi-periodic vibration is found even under harmonic excitation.

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Numerical and Experimental Investigation of an Underplatform Damper Test Rig

Cited by 20 publications

References 31 publications

Modelling the nonlinear behaviour of an underplatform damper test rig for turbine applications

Modelling the nonlinear behaviour of an underplatform damper test rig for turbine applications

A Multiscale Approach for Nonlinear Dynamic Response Predictions With Fretting Wear

Dynamic Response of a Simplified Turbine Blade Model with Under-Platform Dry Friction Dampers Considering Normal Load Variation

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