TY - JOUR A1 - Kühhorn, Arnold A1 - Beirow, Bernd T1 - Schwingungsreduzierung an der Antriebseinheit eines Ultraleichtflugzeuges JF - Forum der Forschung N2 - Auf Grund der im Rahmen eines Testfluges subjektiv durch den Piloten festgestellten hohen Schwingungsamplituden wird das dynamische Verhalten eines Ultraleichtflugzeugmotors inklusive der Motoraufhängung untersucht. Hierin wir der numerische Teil der Untersuchun-gen durch eine finite Elemente Simulation abgedeckt, in deren Rahmen die wesentlichen Ei-genschwingformen der Antriebseinheit samt Motorträger identifiziert wurden. Ergänzend mit den Ergebnissen einer experimentellen Modalanalyse und Betriebsschwingungsmessungen konnten wesentliche Informationen gewonnen werden, aus denen als Maßnahme zur Schwin-gungsreduzierung die Erhöhung der Schwungradmasse abgeleitet wurde. KW - Experimentelle Modalanalyse KW - FEM-Simulation KW - Ultraleichtflugzeug Y1 - 2002 SN - 0947-6989 VL - 6 SP - 105 EP - 108 ET - 14 ER - TY - CHAP A1 - Chmielewski, Tadeusz A1 - Gorski, Piotr A1 - Beirow, Bernd A1 - Kretzschmar, Joachim T1 - Comparison of Theoretical and Experimental Free Vibrations of High Industrial Chimney Interacting with Soil T2 - Teoria konstrukcji, konstrukcje metalowe, konstrukcje betonowe, XLVIII Konferencja Naukowa Komitetu Inżynierii Lądowej i Wodnej PAN i Komitetu Nauki PZITB Krynica 2002, Opole-Krynica 15-20 września 2002 r. N2 - Theoretical frequencies and mode shapes of the high multi-flue industrial chimney, which is located in the power station of Opole, interacting with soil have been evaluated through the application of the finite element method. The aim of the present paper is to study the free vibrations of this chimney applying dynamic testing in full scale to confirm a calculation model and to obtain important information on the effect of soil interacting with the chimney. KW - Free vibration analysis KW - towers KW - Influence of soil KW - vibration measurement Y1 - 2002 SN - 83-7125-091-6 SP - 27 EP - 34 PB - Dolnośląskie Wydaw. Edukacyjne CY - Wrocław ER - TY - CHAP A1 - Beirow, Bernd A1 - Kühhorn, Arnold T1 - Schwingungsreduzierung an der Antriebseinheit eines Ultraleichtflugzeuges : Beitrag Deutscher Luft- und Raumfahrtkongress Stuttgart 2002 N2 - Initiiert durch die im Rahmen eines Testfluges subjektiv durch den Piloten festgestellten hohen Schwingungsamplituden wird das dynamische Verhalten eines Ultraleichtflugzeugmotors inklusive der Motoraufhängung untersucht. Hierin wir der numerische Teil der Untersuchungen durch eine finite Elemente Simulation abgedeckt, in deren Rahmen die wesentlichen Eigenschwingformen der Antriebseinheit samt Motorträger identifiziert wurden. Ergänzend mit den Ergebnissen einer experimentellen Modalanalyse und Betriebsschwingungsmessungen konnten wesentliche Informationen gewonnen werden, aus denen als Maßnahme zur Schwin-gungsreduzierung die Erhöhung der Schwungradmasse abgeleitet wurde. KW - Experimentelle Modalanalyse KW - FEM-Simulation KW - Order-track-Analysen Ultraleichflugzeug Y1 - 2002 ER - TY - CHAP A1 - Beirow, Bernd A1 - Kühhorn, Arnold A1 - Osterrieder, Peter T1 - Windinduzierte Schwingungserregung von Fernmeldetürmen T2 - Fluid-Struktur-Wechselwirkung, Tagung Wiesloch, 11. und 12. Juni 2002 N2 - Vorstellung eines stochastischen Verfahrens zur Berechnung windinduzierter Querschwingungen, Präsentation am Beispiel des Fernmeldeturmes Cottbus KW - stochastische Querschwingungsberechnung KW - Lock-in-Effekt Y1 - 2002 SN - 3-18-091682-6 SP - 407 EP - 422 PB - VDI-Verlag CY - Düsseldorf ER - TY - JOUR A1 - Kühhorn, Arnold A1 - Beirow, Bernd A1 - Studener, Johannes T1 - Messtechnische Beanspruchungsuntersuchungen beim Transport von Glasröhrenkollektoren KW - Beanspruchungsuntersuchungen KW - Glasröhrenkollektoren Y1 - 2003 ER - TY - JOUR A1 - Kühhorn, Arnold A1 - Beirow, Bernd A1 - Klauke, Thomas A1 - Golze, Mark T1 - Simulation der Mistuningeffekte von Hochdruckverdichter-Schaufelscheiben zur Bestimmung kritischer Schwingungen in Flugtriebwerken KW - Mistuningeffekte KW - Blisks Y1 - 2004 ER - TY - CHAP A1 - Beirow, Bernd A1 - Osterrieder, Peter A1 - Kühhorn, Arnold ED - Dinkler, Dieter T1 - Stochastisches Konzept für die Berechnung von Stahlschornsteinen infolge wirbelerregter Querschwingungen T2 - Berichte der Fachtagung Baustatik - Baupraxis 8, am 21. und 22. März 2002 in Braunschweig Y1 - 2002 SN - 3-926031-95-6 SP - 271 EP - 280 PB - TU, Institut für Statik CY - Braunschweig ER - TY - CHAP A1 - Kretzschmar, Joachim A1 - Beirow, Bernd T1 - Dynamic Diagnostic of Timber Structures Supported by Neural Networks Y1 - 2000 ER - TY - CHAP A1 - Klauke, Thomas A1 - Beirow, Bernd A1 - Kühhorn, Arnold T1 - Experimental and numerical investigations of blade mistuning and strain gauge application effects in aero engine development Y1 - 2005 ER - TY - GEN A1 - Chmielewski, Tadeusz A1 - Gorski, Piotr A1 - Beirow, Bernd A1 - Kretzschmar, Joachim T1 - Theoretical and experimental free vibrations of tall industrial chimney with flexibility of soil T2 - Engineering structures Y1 - 2005 SN - 0141-0296 VL - 27 IS - 1 SP - 25 EP - 34 ER - TY - CHAP A1 - Beirow, Bernd A1 - Kühhorn, Arnold A1 - Golze, Mark A1 - Klauke, Thomas T1 - Strukturdynamische Untersuchungen an Hochdruckverdichterschaufelscheiben unter Berücksichtigung von Mistuningeffekten T2 - Modalanalyse und Identifikation, Verfahren und Anwendungen bei dynamischen Systemen, Tagung Wiesloch, 25. und 26. Mai 2004 KW - Verdichterschaufelscheiben KW - Mistuningeffekte Y1 - 2004 SN - 3-18-091825-X SP - 351 EP - 372 PB - VDI-Verlag CY - Düsseldorf ER - TY - CHAP A1 - Klauke, Thomas A1 - Kühhorn, Arnold A1 - Beirow, Bernd T1 - Numerische Untersuchung des Schwingverhaltens von Hochdruckverdichter-Blisks mit fertigungsbedingten Anweichungen KW - Blisks KW - Schwingverhalten Y1 - 2004 ER - TY - CHAP A1 - Beirow, Bernd A1 - Kühhorn, Arnold A1 - Nipkau, Jens T1 - On the Influence of Strain Gauge Instrumentation on Blade Vibrations of Integral Blisk Compressor Rotors Applying a Discrete Model T2 - Proceedings of the ASME Turbo Expo 2009, presented at the 2009 ASME Turbo Expo, June 8 - 12, 2009, Orlando, Florida, USA Y1 - 2009 SN - 978-0-7918-4887-6 N1 - GT2009-59207 SP - 245 EP - 254 PB - ASME CY - New York, NY ER - TY - CHAP A1 - Beirow, Bernd A1 - Osterrieder, Peter ED - Zingoni, Alphose T1 - Dynamic Investigations of TV Towers T2 - Structural engineering, mechanics, and computation, proceedings of the International Conference on Structural Engineering, Mechanics, and Computation, 2-4 April 2001, Cape Town, South Africa, Bd. 1 Y1 - 2001 SN - 0-08-043948-9 SP - 629 EP - 636 PB - Elsevier CY - Amsterdam ER - TY - GEN A1 - Kühhorn, Arnold A1 - Beirow, Bernd A1 - Schrape, Sven A1 - Golze, Mark A1 - Knöpke, Martin T1 - Simulation fluidgedämpfter Strukturschwingungen mittels partitionierter Fluid-Struktur-Kopplung T2 - Forum der Forschung Y1 - 2005 SN - 0947-6989 VL - 9 IS - 18 SP - 79 EP - 86 ER - TY - CHAP A1 - Beirow, Bernd A1 - Kühhorn, Arnold A1 - Klauke, Thomas T1 - Lokalisierungsphänomen bei Hochdruckverdichterschaufelscheiben KW - Schaufelscheiben KW - Hochdruckverdichter Y1 - 2006 ER - TY - JOUR A1 - Kühhorn, Arnold A1 - Beirow, Bernd A1 - Klauke, Thomas T1 - Theoretische und experimentelle Untersuchungen von Schaufelschwingungen bei Verdichterintegralrädern KW - Schaufelschwingungen Y1 - 2006 ER - TY - CHAP A1 - Strehlau, Ulrik A1 - Kühhorn, Arnold A1 - Beirow, Bernd T1 - Numerische und experimentelle Untersuchungen realer Hochdruckverdichterschaufelscheiben in Integralbauweise Y1 - 2009 ER - TY - CHAP A1 - Schrape, S. A1 - Kühhorn, Arnold A1 - Nipkau, Jens A1 - Beirow, Bernd T1 - Application of Aeroelastic Methods in Compressor Cascade Configurations Using Partitioned Code Coupling Y1 - 2008 ER - TY - CHAP A1 - Beirow, Bernd A1 - Kühhorn, Arnold A1 - Schrape, S. T1 - Development of a new Nickel-base Alloy 718Plus for Compressor and Turbine disks Y1 - 2007 ER - TY - CHAP A1 - Klauke, Thomas A1 - Kühhorn, Arnold A1 - Beirow, Bernd T1 - Blade Mistuning Induced Blisk Vibration T2 - 1st CEAS European Air and Space Conference 2007, Deutscher Luft- und Raumfahrtkongress 2007, 10 - 13 September 2007, Berlin, Germany, Bd. 1 Y1 - 2007 SP - 335 EP - 345 PB - Dt. Ges. für Luft- und Raumfahrt CY - Bonn ER - TY - CHAP A1 - Beirow, Bernd A1 - Kühhorn, Arnold A1 - Schrape, S. T1 - Influence of Air Flow on Blisk Vibration Behaviour T2 - 1st CEAS European Air and Space Conference 2007, Deutscher Luft- und Raumfahrtkongress 2007, 10 - 13 September 2007, Berlin, Germany, Bd. 5 Y1 - 2007 N1 - CEAS-2007-058 SP - 3127 EP - 3135 PB - Dt. Ges. für Luft- und Raumfahrt CY - Bonn ER - TY - CHAP A1 - Beirow, Bernd A1 - Kühhorn, Arnold A1 - Schrape, S. T1 - Blisk Vibration Phenomena in Consideration of Fluid Structure Interaction Y1 - 2007 ER - TY - CHAP A1 - Beirow, Bernd A1 - Kühhorn, Arnold A1 - Schrape, S. T1 - A Discrete model to consider the influence of the air flow on blade vibrations of an intergral blisk compressor rotor T2 - Proceedings of the ASME Turbo Expo 2008, presented at the 2008 ASME Turbo Expo, June 9 - 13, 2008, Berlin, Germany, Vol. 5, part A Y1 - 2008 SN - 978-0-7918-4315-4 N1 - GT2008-50613 SP - 381 EP - 392 PB - ASME CY - New York, NY ER - TY - CHAP A1 - Klauke, Thomas A1 - Kühhorn, Arnold A1 - Beirow, Bernd A1 - Parchem, Roland T1 - Blade Vibration Phenomena of HPC Bliscs Considering Manufacturing Effects and Strain Gauge Application T2 - Proceedings of the ASME Turbo Expo 2008, presented at the 2008 ASME Turbo Expo, June 9 - 13, 2008, Berlin, Germany, Vol. 5, part A Y1 - 2008 SN - 978-0-7918-4315-4 SP - 403 EP - 413 PB - ASME CY - New York, NY ER - TY - JOUR A1 - Nipkau, Jens A1 - Schrape, S. A1 - Beirow, Bernd A1 - Kühhorn, Arnold T1 - Bestimmung aeroelastischer Parameter einer Hochdruckverdichter Stufe mit Hilfe Fluid-Struktur gekoppelter Berechnungen Y1 - 2008 ER - TY - CHAP A1 - Giersch, Thomas A1 - Beirow, Bernd A1 - Popig, Frederik A1 - Kühhorn, Arnold T1 - FSI-based forced response analyses of a mistuned high pressure compressor blisk T2 - 10th International Conference on Vibrations in Rotating Machinery, 11-13 September 2012, IMechE London, UK KW - Mistuning KW - Blisk KW - Aeroelastics Y1 - 2012 SN - 978-0-85709-452-0 SN - 0-85709-452-1 N1 - Paper C1326/012 PB - Woodhead Publ. CY - Cambridge, UK ER - TY - CHAP A1 - Beirow, Bernd A1 - Kühhorn, Arnold A1 - Nipkau, Jens T1 - Schwingungsverhalten integraler Hochdruckverdichterlaufräder unter Berücksichtigung von Fluid-Struktur-Wechselwirkung und Mistuning T2 - 61. Deutscher Luft- und Raumfahrtkongress 2012, 10. - 12. September 2012, Estrel Berlin KW - Mistuning KW - Blisk KW - Aeroelastik Y1 - 2012 UR - http://www.dglr.de/publikationen/2012/281219.pdf N1 - Beitrag DLRK2012-281219 PB - Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V. CY - Bonn ER - TY - CHAP A1 - Giersch, Thomas A1 - Hönisch, Peter A1 - Beirow, Bernd A1 - Kühhorn, Arnold T1 - Forced Response Analyses of Mistuned Radial Inflow Turbines T2 - Proceedings of the ASME Turbo Expo 2012 : presented at the 2012 ASME Turbo Expo, June 11 - 15, 2012, Copenhagen, Denmark, Vol. 7, part B KW - Blisk KW - Mistuning KW - Radial Turbine Y1 - 2012 SN - 978-0-7918-4473-1 N1 - Paper GT2012-69556 SP - 1559 EP - 1570 PB - ASME CY - New York, NY ER - TY - GEN A1 - Giersch, Thomas A1 - Hönisch, Peter A1 - Beirow, Bernd A1 - Kühhorn, Arnold T1 - Forced Response Analyses of Mistuned Radial Inflow Turbines T2 - Journal of Turbomachinery N2 - Radial turbine wheels designed as blade integrated disks (blisk) are widely used in various industrial applications. However, related to the introduction of exhaust gas turbochargers in the field of small and medium sized engines, a sustainable demand for radial turbine wheels has come along. Despite those blisks being state of the art, a number of fundamental problems, mainly referring to fluid-structure-interaction and, therefore, to the vibration behavior, have been reported. Aiming to achieve an enhanced understanding of fluid-structure-interaction in radial turbine wheels, a numerical method, able to predict forced responses of mistuned blisks due to aerodynamic excitation, is presented. In a first step, the unsteady aerodynamic forcing is determined by modeling the spiral casing, the stator vanes, and the rotor blades of the entire turbine stage. In a second step, the aerodynamic damping induced by blade vibration is computed using a harmonic balance technique. The structure itself is represented by a reduced order model being extended by aerodynamic damping effects and aerodynamic forcings. Mistuning is introduced by adjusting the modal stiffness matrix based on results of blade by blade measurements that have been performed at rest. In order to verify the numerical method, the results are compared with strain-gauge data obtained during rig-tests. As a result, a measured low engine order excitation was found by modeling the spiral casing. Furthermore, a localization phenomenon due to frequency mistuning could be proven. The predicted amplitudes are close to the measured data. Y1 - 2013 UR - http://turbomachinery.asmedigitalcollection.asme.org/article.aspx?articleid=1672771 U6 - https://doi.org/10.1115/1.4007512 SN - 1528-8900 VL - 135 IS - 3 SP - 031034-1 EP - 031034-9 ER - TY - GEN A1 - Beirow, Bernd A1 - Giersch, Thomas A1 - Kühhorn, Arnold A1 - Nipkau, Jens T1 - Forced Response Analysis of a Mistuned Compressor Blisk T2 - Journal of Engineering for Gas Turbines and Power N2 - The forced response of an E3E-type high pressure compressor (HPC) blisk front rotor is analyzed with regard to varying mistuning and the consideration of the fluid-structure interaction (FSI). For that purpose, a reduced order model is used in which the disk remains unchanged and mechanical properties of the blades, namely stiffness and damping, are adjusted to measured as well as intentional blade frequency mistuning distributions. The aerodynamic influence coefficient technique is employed to model the aeroelastics. Depending on the blade mode, the exciting engine order, and aerodynamic influences, it is sought for the worst mistuning distributions with respect to the maximum blade displacement based on optimization analyses. Genetic algorithms using blade-alone frequencies as design variables are applied. The validity of the Whitehead limit is assessed in this context. In particular, the question is addressed if and how far aeroelastic effects, mainly caused by aerodynamic damping, combined with mistuning can even cause a reduction of the forced response compared to the ideally tuned blisk. It is shown that the strong dependence of the aerodynamic damping on the interblade phase angle is the main driver for a possible response attenuation considering the fundamental as well as a higher blade mode. Furthermore, the differences to the blisk vibration response without a consideration of the flow and an increase of the disk's stiffness are discussed. Closing, the influence of pure damping mistuning is analyzed again using optimization. KW - Blisk Otimization KW - Mistuning Y1 - 2014 U6 - https://doi.org/10.1115/1.4026537 SN - 1528-8919 VL - 136 IS - 6 ER - TY - GEN A1 - Beirow, Bernd A1 - Giersch, Thomas A1 - Kühhorn, Arnold A1 - Nipkau, Jens T1 - Optimization-Aided Forced Response Analysis of a Mistuned Compressor Blisk T2 - Journal of Engineering for Gas Turbines and Power N2 - The forced response of the first rotor of an engine 3E (technology program) (E3E)-type high pressure compressor (HPC) blisk is analyzed with regard to varying mistuning, varying engine order (EO) excitations and the consideration of aero-elastic effects. For that purpose, subset of nominal system modes (SNM)-based reduced order models are used in which the disk remains unchanged while the Young's modulus of each blade is used to define experimentally adjusted as well as intentional mistuning patterns. The aerodynamic influence coefficient (AIC) technique is employed to model aero-elastic interactions. Furthermore, based on optimization analyses and depending on the exciting EO and aerodynamic influences it is searched for the worst as well as the best mistuning distributions with respect to the maximum blade displacement. Genetic algorithms using blade stiffness variations as vector of design variables and the maximum blade displacement as objective function are applied. An allowed limit of the blades' Young's modulus standard deviation is formulated as secondary condition. In particular, the question is addressed if and how far the aero-elastic impact, mainly causing aerodynamic damping, combined with mistuning can even yield a reduction of the forced response compared to the ideally tuned blisk. It is shown that the strong dependence of the aerodynamic damping on the interblade phase angle is the main driver for a possible response attenuation considering the fundamental blade mode. The results of the optimization analyses are compared to the forced response due to real, experimentally determined frequency mistuning as well as intentional mistuning. KW - Mistuning KW - Forced Response KW - Compressor Blisk Y1 - 2015 U6 - https://doi.org/10.1115/1.4028095 SN - 1528-8919 VL - 137 IS - 1 SP - 012504-1 EP - 012504-10 ER - TY - CHAP A1 - Beirow, Bernd A1 - Kühhorn, Arnold A1 - Nipkau, Jens T1 - Forced Response Reduction of a Compressor Blisk Rotor Employing Intentional Mistuning T2 - Advances in Mechanism Design II, Proceedings of the XII International Conference on the Theory of Machines and Mechanisms, 6.-8.9.2016, Liberec N2 - Using the example of a compressor test blisk with 29 blades different sources of mistuning and their consequences for the forced response are analysed under consideration of aeroelastic effects. In particular the impact of superimposing intentional structural mistuning by both random structural mistuning and aerodynamic mistuning is studied. For this purpose reduced order models of the blisk are adjusted for different mistuning distributions. The mistuning itself is characterized by assigning individual stiffness parameters to each blade. The aeroelastic coupling is included employing aerodynamic influence coefficients. By means of genetic algorithm optimizations, structural mistuning patterns are found which yield a mitigation of the forced response below that of the tuned design reference. Ideally a nearly 50 % reduction of maximum response magnitudes is computed for the fundamental bending mode and large mistuning. The solutions found have been proven to be robust with respect to additional random and aerodynamic mistuning in case of large intentional structural mistuning. Y1 - 2016 SN - 978-3-319-44087-3 U6 - https://doi.org/10.1007/978-3-319-44087-3_29 SP - 223 EP - 229 PB - Springer International Publishing CY - Cham ER - TY - GEN A1 - Beirow, Bernd A1 - Figaschewsky, Felix A1 - Kühhorn, Arnold A1 - Bornholm, Alfons T1 - Modal Analyses of an Axial Turbine Blisk With Intentional Mistuning T2 - Journal of Engineering for Gas Turbines and Power N2 - The potential of intentional mistuning to reduce the maximum forced response is analyzed within the development of an axial turbine blisk for ship diesel engine turbocharger applications. The basic idea of the approach is to provide an increased aerodynamic damping level for particular engine order excitations and mode shapes without any significant distortions of the aerodynamic performance. The mistuning pattern intended to yield a mitigation of the forced response is derived from an optimization study applying genetic algorithms. Two blisk prototypes have been manufactured a first one with and another one without employing intentional mistuning. Hence, the differences regarding the real mistuning and other modal properties can be experimentally determined and evaluated as well. In addition, the experimental data basis allows for updating structural models which are well suited to compute the forced response under operational conditions. In this way, the real benefit achieved with the application of intentional mistuning is demonstrated. KW - Modal Analyses KW - Turbines Y1 - 2018 UR - http://gasturbinespower.asmedigitalcollection.asme.org/article.aspx?articleid=2649209#Abstract U6 - https://doi.org/10.1115/1.4037588 SN - 0742-4795 SN - 1528-8919 VL - 140 IS - 1 SP - 012503-1 EP - 012503-11 ER - TY - GEN A1 - Beirow, Bernd A1 - Kühhorn, Arnold A1 - Figaschewsky, Felix A1 - Bornholm, Alfons A1 - Repetckii, Oleg V. T1 - Forced Response Reduction of a Blisk by Means of Intentional Mistuning T2 - Journal of Engineering for Gas Turbines and Power N2 - The effect of intentional mistuning has been analyzed for an axial turbocharger blisk with the objective of limiting the forced response due to low engine order excitation (LEO). The idea behind the approach was to increase the aerodynamic damping for the most critical fundamental mode in a way that a safe operation is ensured without severely losing aerodynamic performance. Apart from alternate mistuning a more effective mistuning pattern is investigated, which has been derived by means of optimization employing genetic algorithms. In order to keep the manufacturing effort as small as possible only two blade different geometries have been allowed which means that an integer optimization problem has been formulated. Two blisk prototypes have been manufactured for the purpose of demonstrating the benefit of the intentional mistuning pattern identified in this way: A first one with and a second one without employing intentional mistuning. The real mistuning of the prototypes has been experimentally identified. It is shown that the benefit regarding the forced response reduction is retained in spite of the negative impact of unavoidable additional mistuning due to the manufacturing process. Independently, further analyzes have been focused on the robustness of the solution by considering increasing random structural mistuning and aerodynamic mistuning as well. The latter one has been modeled by means of varying aerodynamic influence coefficients (AIC) as part of Monte Carlo simulations. Reduced order models have been employed for these purposes. Y1 - 2019 UR - http://gasturbinespower.asmedigitalcollection.asme.org/article.aspx?articleid=2687503 U6 - https://doi.org/10.1115/1.4040715 SN - 1528-8919 SN - 0742-4795 VL - 141 IS - 1 SP - 011008-1 EP - 011008-8 ER - TY - GEN A1 - Beirow, Bernd A1 - Figaschewsky, Felix A1 - Kühhorn, Arnold A1 - Bornholm, Alfons T1 - Vibration Analysis of an Axial Turbine Blisk with Optimized Intentional Mistuning Pattern T2 - Journal of Sound and Vibration N2 - With the objective of attenuating the forced response of an axial turbine blisk for ship Diesel engine applications efforts have been made to increase the aerodynamic damping contribution for the most critical modes. In this regard the potential of intentional mistuning is investigated since it offers the opportunity to ensure a safe operation without a severe loss of aerodynamic performance. Genetic algorithms have been chosen to derive an optimized mistuning pattern resulting in a forced response clearly below that of the tuned counterpart. In order to keep the manufacturing effort within a limit only two possible blade geometries are allowed, which means that an integer optimization problem has been formulated. For the purpose of demonstrating the benefit of the intentional mistuning pattern found, two blisk prototypes have been manufactured: One with and another one without employing intentional mistuning for purposes of comparison. Furthermore, this offers the opportunity for an experimental determination of actually manufactured mistuning and other modal properties as well. The experimental data basis is employed to update structural models, which are well suited to demonstrate the forced response reduction under operational conditions. Finally, the robustness of the gain achieved with intentional mistuning could be proved towards both additional but unavoidable random structural and aerodynamic mistuning. KW - Balde integradet disk KW - Intentional mistuning KW - Vibration KW - Forced response KW - Optimization Y1 - 2019 U6 - https://doi.org/10.1016/j.jsv.2018.10.064 SN - 0022-460X VL - 442 SP - 11 EP - 27 ER - TY - GEN A1 - Weber, Robby A1 - Kühhorn, Arnold A1 - Beirow, Bernd T1 - Mistuning und Dämpfung radialer Turbinen- und Verdichterlaufräder T2 - MTZ - Motortechnische Zeitschrift N2 - Turbolader tragen erheblich zur Steigerung des Motorenwirkungsgrads bei. Rotierende Komponenten sind infolge der Fliehkraft, der zur Aufladung notwendigen Strömungsumlenkungen, der instationären Druckschwankungen der Strömung sowie von Temperaturgradienten als hochbelastete Laufräder einzustufen, die unter erheblicher Schwingungsanfälligkeit leiden. Am Lehrstuhl Strukturmechanik und Fahrzeugschwingungen der BTU Cottbus-Senftenberg wurde im Rahmen eines FVV-Forschungsvorhabens der Einfluss der fertigungsbedingten Toleranzen auf eben jenes Schwingungsverhalten untersucht. Es wird nachgewiesen, dass Intentional Mistuning zu signifikant niedrigeren Belastungen führen kann. KW - Mistuning KW - Dämpfung KW - Turbinen KW - Laufräder Y1 - 2019 U6 - https://doi.org/10.1007/s35146-019-0094-2 SN - 0024-8525 SN - 2192-8843 VL - 80 IS - 9 SP - 74 EP - 78 ER - TY - GEN A1 - Heinrich, Christoph Rocky A1 - Unglaube, Tina A1 - Beirow, Bernd A1 - Brillert, Dieter A1 - Steff, Klaus A1 - Petry, Nico T1 - Surrogate Models for the Prediction of Damping Ratios in Coupled Acoustoelastic Rotor-Cavity Systems T2 - Proceedings of ASME Turbo Expo 2021, ASME Paper Number: GT2021-58835 N2 - The oil and gas, chemical, and process industries employ centrifugal compressors for a wide range of applications. Due to this, the conditions, under which centrifugal compressors have to operate, vary significantly from case to case. Gas pipeline compressors, for example, may feature discharge pressures well over 100 bar. In other fields of application, like gas injection for enhanced oil recovery, discharge pressures over 600 bar and gas densities over 300 kg/m^3 are not uncommon. During the last decades, comprehensive research was conducted on the impact of high pressure operating conditions on the vibrational behavior of centrifugal compressor wheels. In multiple studies, acoustic modes building up in the side cavities were found to be a potential source of high cycle fatigue in radial compressors. Nowadays, it is well-known that an increase in gas pressure levels leads to a more pronounced fluid-structure interaction between the side cavities and the impeller resulting in a frequency shift of the acoustic and structural modes. For the safe operation of compressors, it is necessary to predict these coupled natural frequencies accurately. The state-of-the-art approach to achieve this objective is the finite element method. In a recently published paper, the authors presented a generalized model to predict the natural frequencies and mode shapes of acoustoelastic rotor-cavity systems. This approach reduces the computational cost significantly while retaining the accuracy of a finite element simulation. So far, the model was only validated using measurement data of an impeller at standstill under varying cavity pressures. In this study, the authors show that the generalized model can predict the natural frequencies of rotating systems with sufficient accuracy by using measurement data of a disk spinning at multiple rotational speeds in a cylindrical cavity. As it is not always possible to avoid operating close to or accelerate through a resonance of the compressor, it is crucial to know the damping present within the system that limits the amplitudes for a given excitation force. While many studies focus on the identification of damping ratios in axial turbomachines, only a few publications concentrate on the damping of radial impellers. Therefore, the authors present measurement data acquired from the test rig at University Duisburg-Essen, Chair of Turbomachinery, which reveals the damping behavior of a spinning disk under varying operating conditions. Three surrogate models are proposed to predict the identified damping behavior. The first one is based solely on a one-dimensional piston model. The second approach uses an enhanced version of the generalized method, while the third one is a combination of both. After deriving these three models, the measurement data is used to validate the surrogate systems. The paper concludes with a discussion of the measurement results and the benefits and limitations of the proposed models. Y1 - 2021 UR - https://asme-turboexpo.secure-platform.com/a/solicitations/137/sessiongallery/7270/application/58835 ER - TY - GEN A1 - Nakos, Alex A1 - Beirow, Bernd A1 - Zobel, Arthur T1 - Mistuning and Damping of a Radial Turbine Wheel. Part 1: Fundamental Analyses and Design of Intentional Mistuning Pattern T2 - Proceedings of ASME Turbo Expo 2021, ASME Paper Number: GT2021-59283 N2 - The radial turbine impeller of an exhaust turbocharger is analyzed in view of both free vibration and forced response. Stator vane rings located upstream between engine and turbine wheel are applied to guide the exhaust gases in optimized flow directions. Hence, turbine wheels are subjected to aerodynamic excitations causing forced vibrations of blades and the whole turbine. Due to random blade mistuning resulting from unavoidable inaccuracies in manufacture or material inhomogeneities, localized modes of vibration may arise, which involve the risk of severely magnified blade displacements and inadmissibly high stress levels compared to the tuned counterpart. In consequence, damages may occur along with a dramatic decrease of efficiency or even a total failure during engine operation as worst-case scenarios. Contrary, the use of intentional mistuning has proved to be an efficient measure to mitigate the forced response. Independently, the presence of aerodynamic damping is significant with respect to limit the forced response since structural damping ratios of blade integrated disks (blisks) typically take extremely low values. Thus, a detailed knowledge of respective damping ratios would be desirable while developing a robust blisk design. For this, far-reaching experimental investigations are carried out to determine damping curves of a comparative wheel within a wide pressure range by simulating operation conditions in a pressure tank. They are the basis to develop empirical formulas for damping estimation which could be be taken into account during future design processes. In order to get an idea of the real structural behaviour, further measurements are conducted to determine the present mistuning of the turbine wheel, which facilitates to update structural models and finally allows to compute the forced response in an accurate manner. Reduced order models are built up for designing suitable intentional mistuning patterns by using the subset of nominal system mode (SNM) approach introduced by Yang and Griffin [1], which conveniently allows for accounting both differing mistuning patterns and the impact of aeroelastic interaction. For this, the aerodynamic damping curves are determined by means of computational flow simulations. The SNM approach finally provides appropriate mistuning patterns by conducting optimization studies based on genetic algorithms. The robustness of the found solutions is proved by additionally superimposing both random mistuning and experimentally determined mistuning of the original wheel. Finite element analyses are carried out in order to identify appropriate measures to implement intentional mistuning patterns, which are featuring only two different blade designs. In detail, the impact of specific geometric modifications on blade natural frequencies is investigated. After implementation of the intentional mistuning pattern, which will be described in Part 2 of this paper later on, the success of taken measures will be reviewed based on both, experimental testing at standstill conditions and in a test stand by running the wheel under realistic operational conditions. [1] Yang, M. T., Griffin, J. H., „A Reduced-Order model of Mistuning Using a Subset of Nominal System Modes“. J Eng Gas Turb Power, 123, pp. 893-900 (2001). Y1 - 2021 UR - https://asme-turboexpo.secure-platform.com/a/solicitations/137/sessiongallery/7263/application/59283 ER - TY - GEN A1 - Nakos, Alex A1 - Beirow, Bernd A1 - Zobel, Arthur T1 - Mistuning and Damping of a Radial Turbine Wheel. Part 1: Fundamental Analyses and Design of Intentional Mistuning Pattern T2 - Journal of Engineering for Gas Turbines and Power N2 - The radial turbine impeller of an exhaust turbocharger is analyzed in view of both free vibration and forced response. Due to random blade mistuning resulting from unavoidable inaccuracies in manufacture or material inhomogeneities, localized modes of vibration may arise, which involve the risk of severely magnified blade displacements and inadmissibly high-stress levels compared to the tuned counterpart. Contrary, the use of intentional mistuning (IM) has proved to be an efficient measure to mitigate the forced response. Independently, the presence of aerodynamic damping is significant with respect to limit the forced response since structural damping ratios of integrally bladed rotors typically take extremely low values. Hence, detailed knowledge of respective damping ratios would be desirable while developing a robust rotor design. For this, far-reaching experimental investigations are carried out to determine the damping of a comparative wheel within a wide pressure range by simulating operation conditions in a pressure tank. Reduced-order models are built up for designing suitable intentional mistuning patterns by using the subset of nominal system modes approach introduced by Yang and Griffin (2001, “A Reduced-Order Model of Mistuning Using a Subset of Nominal System Modes,” J. Eng. Gas Turbines Power, 123(4), pp. 893–900), which conveniently allows for accounting both differing mistuning patterns and the impact of aeroelastic interaction by means of aerodynamic influence coefficients. Further, finite element analyses are carried out in order to identify appropriate measures of how to implement intentional mistuning patterns, which are featuring only two different blade designs. In detail, the impact of specific geometric modifications on blade natural frequencies is investigated. The first part of this three-part paper is focused on designing the IM pattern. The second and third part following, later on, will address the topics (i) experimental validation after implementation of the IM pattern at rest and under rotation, and (ii) the development of an approach for fast estimating damping ratios in the design phase. KW - mistuning KW - blade vibration KW - damping Y1 - 2022 SN - 1528-8919 VL - 144 IS - 2 ER - TY - GEN A1 - Heinrich, Christoph Rocky A1 - Unglaube, Tina A1 - Beirow, Bernd A1 - Brillert, Dieter A1 - Steff, Klaus A1 - Petry, Nico T1 - Surrogate Models for the Prediction of Damping Ratios in Coupled Acoustoelastic Rotor-Cavity Systems T2 - Journal of Engineering for Gas Turbines and Power N2 - Centrifugal compressors are versatile machines that many industries employ for a wide range of different applications, including the production of highly compressed gases. During the last decades, comprehensive research was conducted on the impact of high-pressure operating conditions on the vibrational behavior of radial compressors. In various studies, acoustic modes building up in the side cavities were found to be a potential source of high cycle fatigue. Nowadays, it is well-known that an increase in gas pressure levels leads to a more pronounced fluid-structure interaction between the side cavities and the impeller resulting in a frequency shift of the acoustic and structural modes. In a recently published paper, the authors presented a generalized model which can predict this behavior. As it is not always possible to avoid operating close to or accelerating through a resonance, it is crucial to know the damping present within the system. Currently, only a few publications concentrate on the damping of radial impellers. Therefore, the authors present measurement data acquired from a test rig at the University of Duisburg-Essen, which reveals the damping behavior of a disk under varying operating conditions. Two surrogate models are proposed to predict the identified damping behavior. The first one is based solely on a one-dimensional piston model and the second approach uses an enhanced version of the generalized method. Finally, the measurement data is used to validate both surrogate systems. KW - Cavities KW - Damping KW - Rotors KW - Acoustics Y1 - 2022 U6 - https://doi.org/10.1115/1.4054567 SN - 1528-8919 N1 - GTP-21-1478 VL - 144 IS - 8 ER - TY - GEN A1 - Repetckii, Oleg V. A1 - Vinh, Nguyen Van A1 - Beirow, Bernd T1 - Sensitivity Analysis Regarding the Impact of Intentional Mistuning on Blisk Vibrations T2 - Mechanisms and Machine Science N2 - The effect of different intentional mistuning (IM) patterns is investigated with respect to the forced response of an academic axial blisk. It could be shown in numerical analyses that a preliminary use of sensitivity algorithms helps to understand the feasibility and efficiency of introducing geometric changes of the blades. The implementation of IM patterns requires conducting intensive sensitivity studies based on FE simulations in order to identify the consequences of slight geometrical blade modifications on natural frequencies. Typical changes might be a modification of fillet radii or partial modifications of blade thickness, which are most suitable to adjust a target natural frequency without a severe loss of aerodynamic performance. A software tool developed at Irkutsk SAU is employed to evaluate the impact of mass and stiffness contributions, and with that, geometric deviations on blade natural frequencies. Intensive blade vibration due to aerodynamic excitation of blisks is known as major source of high cycle fatigue, which may cause severe failures of turbine and compressor wheels during operation. The problem is relevant for several sectors of industry such as power generation, aviation or vehicle manufacturing. In consequence, there is a broad request of preventing any inadmissible vibration at any time. The application of IM can be regarded as powerful tool to avoid both, large forced responses and self-excited vibration. However, there is a lack of knowledge about how to implement mistuning without strong distortions of the flow passage. The main objective of this work is to close this gap based on comprehensive numerical analyses with regard to the effects of intended geometric modifications of blades on modal quantities. Using FE models, the effectiveness of the proposed block models of mistuning is analyzed with and without taking into account the operational speed of the axial impeller. In conclusion, the consequences of different IM implementations on the forced response of an academic blisk are discussed. In particular, the most promising IM patterns are identified yielding the least forced response. KW - Intentional Mistuning KW - Sensitivity KW - Blisk KW - Forced Response Y1 - 2022 U6 - https://doi.org/10.1007/978-3-031-15758-5_41 SN - 2211-0992 SN - 2211-0984 VL - 125 SP - 408 EP - 415 PB - Springer CY - Cham ER - TY - GEN A1 - Nakos, Alex A1 - Beirow, Bernd A1 - Zobel, Arthur T1 - Mistuning and Damping of a Radial Turbine Wheel. Part 2: Implementation and Validation of Intentional Mistuning T2 - ASME 2022 Turbomachinery Technical Conference & Exposition (GT2022) N2 - A radial turbine impeller of an exhaust turbocharger is analyzed in view of both free vibration and forced response. Due to random blade mistuning resulting from unavoidable inaccuracies in manufacture or material inhomogeneities, localized modes of vibration may arise, which involve the risk of severely magnified blade displacements and inadmissibly high stress levels compared to the tuned counterpart. Contrary, the use of intentional mistuning (IM) has proved to be an efficient measure to mitigate the forced response. In part one of this three-part paper fundamental analyses have been carried out to find a suitable intentional mistuning pattern which is featuring only two different blade designs [1]. This part is focused on the implementation and validation of the intentional mistuning pattern and discusses the detailed geometric adaption of the turbine wheel hardware. The final design of the geometric adaption is developed in terms of manufacturability and efficiency so that a reliable and robust solution is presented. Its machined adaption is validated by both vibration testing at rest and optical measurements so that manufacturing deviations are detected and their impacts discussed and evaluated. Reduced order models are built up for checking the effect of the implemented intentional mistuning pattern on the forced response by using the subset of nominal system modes (SNM) approach introduced by Yang and Griffin [2], which conveniently allows for accounting both the design intention of the mistuning pattern and the actually machined implementation due to manufacturing deviations. Y1 - 2022 UR - https://asme-turboexpo.secure-platform.com/a/solicitations/167/sessiongallery/10144/application/80643 ER - TY - GEN A1 - Gambitta, Marco A1 - Beirow, Bernd A1 - Klauke, Thomas T1 - Investigation of Rear Blisk Drum Dynamics Under Consideration of Multi-Stage Coupling T2 - ASME Journal of Engineering for Gas Turbines and Power N2 - The analysis of the structural dynamics of multistage cyclic structures as linked components is required to model the interstage coupling. In turbomachinery, this can result in a collaboration between different compressor or turbine stages. This paper investigates the coupling between two rear drum blade integrated disk stages of an axial compressor to support the mechanical design process. Considering the vibration modeshapes of a multistage system, different components may coparticipate in the dynamics. For this reason, criteria to identify the modes affected by the coupling and to quantify this coupling are defined. This allows to distinguish between modes with interstage coupling, requiring the multistage system for their description, and uncoupled modes, involving a single stage. In addition, it is of interest to research methods to reduce the impact of the coupling on the vibrating system without drastically altering the geometry of the components. The vibration analyses of a two-stage compressor generalized geometry, representative of a compressor rear drum blisk, are presented as a study case. The use of a reducing method allows to describe the behavior of the nominal multistage system with a computationally efficient technique, enabling a parametric analysis of the stages' coupling. The investigation considers the effect of a set of geometrical and mechanical parameters on the dynamics, identifying the driving parameters of the coupled vibration characteristics. Y1 - 2024 U6 - https://doi.org/10.1115/1.4063633 VL - 146 IS - 2 ER - TY - GEN A1 - Beirow, Bernd A1 - Golze, Mark A1 - Popig, Frederik T1 - Vibration Reduction of a Steam Turbine Wheel by Means of Intentional Mistuning T2 - Advances in Mechanism Design III : Proceedings of TMM 2020 N2 - A last stage steam turbine wheel is analyzed with the objective to alleviate the flutter susceptibility by employing intentional mistuning (IM). In particular, the operation at nominal speed under part-load conditions may cause unfavorable flow conditions facilitating flow separation. In consequence, negative aerodynamic damping ratios occur for the first bending mode family in some circumstances. Employing intended alternate mistuning of adequate magnitude has proved to be a promising measure to stabilize rotors in terms of avoiding self-excited vibration phenomena. From the manufacturing point of view, this two-blade design is advantageous as well and hence, chosen here as a first measure to attenuate flutter susceptibility. Two prototypes of bladed disks series have been made, which are exhibiting small but unavoidable deviations from the design intention due to manufacturing. The real blade alone frequencies have been identified within foregoing experimental investigations. Numerical modal analyses carried out for the prototypes as manufactured finally reveal that there is an additional positive contribution of random mistuning in terms of further enhancing the least aerodynamic damping ratio. Another promising and robust IM pattern is found by using generic algorithms to optimize the least aerodynamic damping ratio yielding stable conditions at any time as well. Moreover, it shows that IM combined with random mistuning also mitigates the maximum forced response at part-speed conditions. KW - Intentional mistuning KW - Blade vibration KW - Flutter KW - Forced response KW - Optimization KW - Aeroelastics Y1 - 2022 SN - 978-3-030-83593-4 SN - 978-3-030-83594-1 U6 - https://doi.org/10.1007/978-3-030-83594-1_8 SN - 2211-0984 SN - 2211-0992 SP - 73 EP - 82 PB - Springer CY - Cham ER - TY - CHAP A1 - Beirow, Bernd A1 - Figaschewsky, Felix A1 - Kühhorn, Arnold T1 - An Inverse Approach to Identify Tuned Aerodynamic Damping, System Frequencies, and Mistuning, Part 2: Application to Blisks at Rest T2 - Proceedings of the 15th International Symposium on Unsteady Aerodynamics, Aeroacoustics & Aeroelasticity of Turbomachines, ISUAAAT15, 24-27 September 2018, University of Oxford, UK Y1 - 2018 UR - https://www-docs.b-tu.de/fg-strukturmechanik/public/ISUAAAT15-021-Beirow_Kuehhorn_Figaschewsky-SystemID_Part2.pdf PB - ISUAAAT Scientific Committee ER - TY - CHAP A1 - Koch, Ilja A1 - Beirow, Bernd A1 - Filippatos, Angelos A1 - Kühhorn, Arnold A1 - Gude, Maik T1 - Methodical Approach for Simulation the Vibration of Damaged Fibre Reinforced Composite Rotors Under Consideration of Aerodynamic Influences T2 - 18th European Conference on Composite Materials (ECCM18), Athen (Griechenland), 25.-28. Juni 2018 Y1 - 2018 UR - https://pcoconvin.eventsair.com/QuickEventWebsitePortal/eccm/program/Agenda/AgendaItemDetail?id=258960e5-a867-4c02-b01e-4c997026cf20 ER - TY - CHAP A1 - Beirow, Bernd A1 - Kühhorn, Arnold A1 - Figaschewsky, Felix A1 - Bornholm, Alfons A1 - Repetckii, Oleg V. T1 - Forced Response Reduction of a Blisk by Means of Intentional Mistuning T2 - ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition, Volume 7C: Structures and Dynamics, Oslo, Norway, June 11–15, 2018 N2 - The effect of intentional mistuning has been analyzed for an axial turbocharger blisk with the objective of limiting the forced response due to low engine order excitation (LEO). The idea behind the approach was to increase the aerodynamic damping for the most critical fundamental mode in a way that a safe operation is ensured without severely losing aerodynamic performance. Apart from alternate mistuning a more effective mistuning pattern is investigated, which has been derived by means of optimization employing genetic algorithms. In order to keep the manufacturing effort as small as possible only two blade different geometries have been allowed which means that an integer optimization problem has been formulated. Two blisk prototypes have been manufactured for the purpose of demonstrating the benefit of the intentional mistuning pattern identified in this way: A first one with and a second one without employing intentional mistuning. The real mistuning of the prototypes has been experimentally identified. It is shown that the benefit regarding the forced response reduction is retained in spite of the negative impact of unavoidable additional mistuning due to the manufacturing process. Independently, further analyzes have been focused on the robustness of the solution by considering increasing random structural mistuning and aerodynamic mistuning as well. The latter one has been modeled by means of varying aerodynamic influence coefficients (AIC) as part of Monte Carlo simulations. Reduced order models have been employed for these purposes. KW - Engines KW - Manufactoring KW - Simulation KW - Turbochargers KW - Damping KW - Optimization Y1 - 2018 SN - 978-0-7918-5115-9 U6 - https://doi.org/10.1115/GT2018-76584 PB - ASME CY - New York, NY ER - TY - CHAP A1 - Beirow, Bernd A1 - Figaschewsky, Felix A1 - Kühhorn, Arnold A1 - Bornholm, Alfons T1 - Vibration Analysis of an Axial Turbine Blisk with Optimized Intentional Mistuning Pattern T2 - Proceedings of ISROMAC 2017, Maui, Hawaii, December 16-21, 2017 N2 - Aiming to limit the forced response of an axial turbine blisk for ship Diesel engine applications efforts have been made to increase the aerodynamic damping contribution for the most critical modes. In this regard the potential of intentional mistuning is investigated since it offers the opportunity to ensure a safe operation without a severe loss of aerodynamic performance. Genetic algorithms have been chosen to derive an optimized mistuning pattern. In order to keep the manufacturing effort within a limit only two possible blade geometries are allowed which means that an integer optimization problem has been formulated. For the purpose of demonstrating the benefit of the intentional mistuning pattern found, two blisk prototypes have been manufactured: One with and another one without employing intentional mistuning for purposes of comparison. Furthermore, this offers the opportunity for an experimental determination of mistuning being really manufactured and other modal properties as well. The experimental data basis is employed to update structural models which are well suited to demonstrate the forced response reduction under operational conditions. KW - Blisk KW - Intentional Mistuning KW - Low Engine Order Excitation Y1 - 2017 UR - http://isromac-isimet.univ-lille1.fr/index.php?rubrique=abstract17_&num=21 ER - TY - CHAP A1 - Figaschewsky, Felix A1 - Kühhorn, Arnold A1 - Beirow, Bernd A1 - Giersch, Thomas A1 - Schrape, Sven T1 - Analysis of Mistuned Forced Response in an Axial High Pressure Compressor Rig With Focus on Tyler-Sofrin Modes T2 - ISABE 2017, ISABE-2017-22614, Manchester, September 3.-8., 2017 Y1 - 2017 PB - ISABE ER -