Modelling friction characteristics in turbine blade vibrations using a fourier series expansion of a real friction hysteresis

Hoffmann, T.; Scheidt, Lars Panning‐von; Wallaschek, Jörg

doi:10.1016/j.proeng.2017.09.586

Cited by 3 publications

(1 citation statement)

References 12 publications

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“…where ρ is the density, can be derived by substituting (3), (4), (5) into (6). Due to the complexity of the resulting relation, it is not presented in this paper.…”

Section: Kinetic and Deformation Potential Energies Of One Finite Elementioning

confidence: 99%

1D finite element for modelling of turbine blade vibration in the field of centrifugal forces

Dupal

Zajíček

Lukeš

2019

ACM

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The paper deals with the modelling of turbine blade vibrations by means of a novel 1D finite element that has only 16 degrees of freedom. Assuming linear elastic behaviour of the blade material and considering small displacements and strains, the derived blade finite element takes into account the effects of tension, torsion and bending in accordance with the Bernoulli's hypothesis. Additionally, the finite element interlinks bending and torsion, and respects membrane forces acting on the blade. The derivation of matrices and vectors describing the blade finite element is provided in detail by using the Lagrange's equations while the effect of membrane forces is included via the virtual work principle. For modelling purposes, the mathematical model of a turbine blade requires only the knowledge of cross-section contour points at several selected sections along the turbine blade axis. On the basis of these points, cross-section characteristics including the warping function are approximated along the blade axis by means of cubic splines. The advantage of this approach lies in the fact that all the blade cross-section parameters are identified before running numerical simulations. The warping function introduced in this paper and derived by variational principle describes cross-section warping caused just by torsion of a prismatic rod. For the verification of the proposed 1D finite element, an analysis of modal properties of the turbine blade M6 L-1 manufactured by Doosan Š koda Power is performed. This is achieved by comparing the lowest natural frequencies and corresponding mode shapes computed by the 1D and 3D models for a standing blade. The results revealed good agreement between both models despite the significant difference in their degrees of freedom. The applicability of the 1D finite element is further demonstrated by analyzing the dependence of natural frequencies on rotor speed.

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“…where ρ is the density, can be derived by substituting (3), (4), (5) into (6). Due to the complexity of the resulting relation, it is not presented in this paper.…”

Section: Kinetic and Deformation Potential Energies Of One Finite Elementioning

confidence: 99%

1D finite element for modelling of turbine blade vibration in the field of centrifugal forces

Dupal

Zajíček

Lukeš

2019

ACM

View full text Add to dashboard Cite

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Modeling and nonlinear dynamics analysis of a rotating beam with dry friction support boundary conditions

Liu

Tang

et al. 2021

Journal of Sound and Vibration

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Analysis of Contacts in Friction Damped Turbine Blades Using Dimensionless Numbers

Hoffmann

Scheidt

Wallaschek

2019

Journal of Engineering for Gas Turbines and Power

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A novel design approach for friction hysteresis measurements is introduced to simplify the characterization of turbine blade contact dynamics. It makes use of dimensionless numbers of a metallic friction contact undergoing small, periodic displacements. Such contacts are used in turbine blades to lower resonance amplitudes by energy dissipation through friction. Nonetheless, this approach is not limited to this field. The dimensionless numbers for characterization of the contact are derived based on a generic contact that is typical for applications in turbine blades. A dimensionless number can be found that characterizes the contact extensively. Several friction hysteresis measurements are conducted on a special test rig in a systematic manner exploring a large parameter space for the derived dimensionless number. Based on the experiments, it is concluded that the normalized measured friction hysteresis loops show similitude despite being measured with parameters spanning a wide range. It results in the possibility to design friction hysteresis tests for friction damped turbine blades in a simple and representative way.

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Modelling friction characteristics in turbine blade vibrations using a fourier series expansion of a real friction hysteresis

Cited by 3 publications

References 12 publications

1D finite element for modelling of turbine blade vibration in the field of centrifugal forces

1D finite element for modelling of turbine blade vibration in the field of centrifugal forces

Modeling and nonlinear dynamics analysis of a rotating beam with dry friction support boundary conditions

Analysis of Contacts in Friction Damped Turbine Blades Using Dimensionless Numbers

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