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The vibrational behaviour of bladed disks with multiple coupling devices
Author(s) -
Hohl A.,
Panning L.,
Siewert C.,
Buerge A.
Publication year - 2007
Publication title -
pamm
Language(s) - English
Resource type - Journals
ISSN - 1617-7061
DOI - 10.1002/pamm.200700724
Subject(s) - damper , coupling (piping) , turbomachinery , vibration , dissipation , structural engineering , stiffness , turbine blade , resonance (particle physics) , mechanics , excitation , turbine , rotor (electric) , engineering , materials science , mechanical engineering , acoustics , physics , electrical engineering , particle physics , thermodynamics
In turbomachinery applications turbine blades are subjected to high static and dynamic loads. Static loads are due to centrifugal stresses and thermal strains. Especially the dynamic excitation caused by fluctuating gas forces results in high vibration amplitudes which can lead to high cycle fatigue failures (HCF). Therefore, in practical applications, coupling devices like underplatform dampers, lacing wires and tip shrouds are installed to the structure. In case of blade vibrations the relative displacements between these coupling devices and the blades generate friction forces. The resulting energy dissipation provides additional damping to the structure. Furthermore, coupling devices, in particular tip shrouds, snubbers and lacing wires, increase the stiffness of the structure. Hence, they lead to a shift of the resonance frequencies. So far, only effects of single coupling devices and the influencing properties have been examined. Within this paper the effect of multiple couplings is determined and compared with single couplings. The forced response of turbine bladings with multiple couplings is calculated under consideration of geometrical and mechanical parameters of the blading and contacts, respectively. The results are compared with the single coupled blading. Furthermore, a multiple coupled device with under‐platform damper and connecting pin is compared with respect to his effectiveness. Especially the influence on the resonance frequency and the achievable damping is analysed. The results of the simulation are verified by measurements at a two‐blade non‐rotating test rig with an underplatform damper and connecting pin. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)