Research

Simulating Turbine Blade Vibrations

Using the newly developed calculation methodology, it is possible to determine the vibration response of turbine blades with connecting elements, such as cover bands. This methodology is based on the Multiharmonic Balance Method, which approximates the static vibrations of a non-linear coupled dynamic system through periodic vibration. Using a test stand developed during the project, the calculation of necessary model parameters was determined. In order to guarantee broad practical application, this methodology is applied in a program code that can be combined with a variety of simulation programs used in industry. In this way, the project makes an important contribution to the optimal design of heavily loaded turbine blades.

» In the FVV we have a unique chance to work on complex topics such as the vibration behaviour of friction-dampened systems in a scientifically sound manner while remaining at all times practice-oriented. «
Dr.-Ing. Andreas Kayser (Siemens AG)

Motivation

Turbine blades are subject to high static and dynamic loads. These cause blade vibrations, which can lead to severe damage. The use of connecting elements, such as cover bands for example, leads to a reduction of the vibration amplitude because of hardening and friction dampening. In order to design the connecting elements optimally, it is essential to have precise knowledge of the vibration behaviour of friction-dampened systems.

Methodology

In order to model the friction dampening as realistically as possible, the Multiharmonic Balance Method was used for calculating the vibration. Thus the periodic, static vibrations of a non-linear connected dynamic system are approximated through the superimposing of harmonic vibrations. The modelling of the frictional contact occurs over one or more point-to-point contacts or through the adoption of two rigid planes in contact. A test stand developed in the project also makes it possible to experimentally determine friction hysteresis. This work forms the basis for determining the model parameters of friction coefficient and tangential stiffness.

Result

With this new method the dynamic behaviour of friction-dampening structures can be calculated with real, expanded joints and thus the vibration response of turbine blades with friction contacts. At the same time it also considers the higher frequency rates of vibrations and vibration responses. In this way, the method is capable of depicting real applications and application areas. With the help of program codes, which can be combined with industrial simulations programs, the method can be directly implemented in practice.

Documentation

High-order Harmonic Balance I | Optimisation of component joints considering multi-frequency vibration excitation and non-linear contact forces in frequency range | Project No. 961

High-order Harmonic Balance II | Optimisation of component joints considering multi-frequency vibration excitation and non-linear contact forces in frequency range | Project No. 1045 | DFG Funding ID 578360

Ninlinear Blade Vibrations | Improvement of the FoReBlade-code for nonlinearly coupled structures vibratory response under consideration of higher harmonic approaches | Project No. 1158

Themis

Status
Finalised

Programme
Public & FVV Funding

Budget
440,050.00 EUR

Time Period
2008-04-01 to 2010-03-31 Part I
2010-07-01 to 2012-06-30 Part II
2014-01-01 to 2016-06-30 Part III

Research Association for Combustion Engines (FVV) eV

Lyoner Strasse 18
60528 Frankfurt am Main
Germany

German Research Foundation (DFG) eV

Kennedyallee 40
53175 Bonn
Germany

Industry

Dr.-Ing. Andreas Kayser | I+II
Siemens AG

Dipl.-Ing. Markus Denk | III
Dr.-Ing. Pierre-Alain Masseray | III
General Electric (Switzerland) GmbH

RTD Performer

Institute of Dynamics and Vibration Research (IDS) | Leibniz University Hannover

Head of Research:
Prof. Dr.-Ing. Jörg Wallaschek

Research Associates:
Dipl.-Ing. Marius Bonhage | III
Dipl.-Ing. Anna Herzog | I-III
Dipl.-Ing. Ferhat Kaptan | III
Dipl.-Ing. Christian Siewert | I+II

Leibniz University Hannover

Institute of Dynamics and Vibration Research (IDS)

Appelstrasse 11
30167 Hanover
Germany

Project Management

Stefanie Jost-Köstering

FVV
+49 (0) 69 6603 1531
+49 (0) 69 6603 2531


Research Association for Combustion Engines eV

Lyoner Strasse 18
60528 Frankfurt am Main
Germany
T +49 69 6603 1345