TY - CHAP A1 - Beirow, Bernd A1 - Kühhorn, Arnold A1 - Golze, Mark T1 - Experimental and Numerical Investigations of High pressure Compressor Blades Vibration Behavior Considering Mistuning KW - vibration Y1 - 2005 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 - Experimentelle Untersuchungen des strukturdynamischen Verhaltens von Hochdruckverdichterschaufeln in Integralbauweise (Blisks) mittels Laser-Doppler-Vibrometrie KW - Blisks KW - Integralbauweise Y1 - 2004 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 - THES A1 - Beirow, Bernd T1 - Experimentelle und theoretische Untersuchungen des dynamischen Verhaltens von Fernmeldetürmen Y1 - 2000 PB - BTU, Lehrstuhl Statik und Dynamik CY - Cottbus 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 - 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 - JOUR A1 - Osterrieder, Peter A1 - Beirow, Bernd T1 - Advanced dynamic methods for structural evaluation of TV towers, Proseedings of the Centre of Structural Integrity Y1 - 2003 ER - TY - CHAP A1 - Beirow, Bernd A1 - Kühhorn, Arnold A1 - Klauke, Thomas T1 - Lokalisierungsphänomen bei Hochdruckverdichterschaufelscheiben KW - Schaufelscheiben KW - Hochdruckverdichter Y1 - 2006 ER - TY - CHAP A1 - Kühhorn, Arnold A1 - Beirow, Bernd A1 - Parchem, Roland A1 - Klauke, Thomas T1 - Schaufelschwingungen bei realen Verdichter-Integralrädern (BLISK) T2 - Deutscher Luft- und Raumfahrtkongress 2006, Braunschweig, 06. bis 09. November 2006, Bd. 2 KW - Schaufelschwingungen KW - Blisk Y1 - 2006 SP - 1199 EP - 1208 PB - Dt. Ges. für Luft- und Raumfahrt CY - Bonn 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 - JOUR A1 - Beirow, Bernd T1 - Secure Power for Jet Engines KW - Jet Engines Y1 - 2006 ER - TY - THES A1 - Beirow, Bernd T1 - Grundlegende Untersuchungen zum Schwingungsverhalten von Verdichterlaufrädern in Integralbauweise Y1 - 2009 SN - 978-3-8322-8729-0 PB - Shaker CY - Aachen 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 - Kühhorn, Arnold A1 - Beirow, Bernd A1 - Strehlau, Ulrik T1 - Zum Schwingungsverhalten integraler Hochdruckverdichterlaufräder Y1 - 2009 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 - GEN A1 - Klauke, Thomas A1 - Kühhorn, Arnold A1 - Beirow, Bernd A1 - Golze, Mark T1 - Numerical Investigations of Localized Vibrations of Mistuned Blade Integrated Disks (Blisks) Y1 - 2009 ER - TY - CHAP A1 - Beirow, Bernd A1 - Kühhorn, Arnold A1 - Nipkau, Jens T1 - An Equivalent Blisk Model Considering the Influence of the Air Flow on Blade Vibrations of a Mistuned Compressor Blisk T2 - Vibration Problems ICOVP 2011, The 10th International Conference on Vibration Problems, The 10th International Conference on Vibration Problems KW - Mistuned Compressor Blisk KW - Blade Vibrations KW - Air Flow Y1 - 2011 SN - 978-94-007-2068-8 SP - 549 EP - 555 PB - Springer CY - Berlin [u.a.] ER - TY - CHAP A1 - Beirow, Bernd A1 - Nipkau, Jens A1 - Kühhorn, Arnold T1 - Modal and Aeroelastic Analysis of a Compressor Blisk Considering Mistuning T2 - Proceedings of the ASME Turbo Expo 2011, presented at the ASME 2011 Turbo Expo, June 6 - 10, 2011, Vancouver, British Columbia, Canada, Vol. 6, part B KW - Mistuning KW - Compressor Blisk Y1 - 2011 SN - 978-0-7918-5466-2 N1 - GT2011-45849 SP - 1309 EP - 1319 PB - ASME CY - New York, NY ER - TY - CHAP A1 - Höhnisch, Peter A1 - Kühhorn, Arnold A1 - Beirow, Bernd T1 - Experimental and Numerical Analysis of Radial Turbine Bliks with Regard to Mistuning KW - Tadial KW - Turbine KW - Vibration KW - Mistuning KW - Model Update Y1 - 2011 ER - TY - CHAP A1 - Nipkau, Jens A1 - Kühhorn, Arnold A1 - Beirow, Bernd T1 - Modal and Aeroelastic Analysis of a Mistuned Compressor Blisk Using an Equivalent Blisk Model KW - Blisk vibration KW - Mistuning KW - Aerodynamic Influence Coefficients Y1 - 2011 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 - CHAP A1 - Beirow, Bernd A1 - Kühhorn, Arnold A1 - Giersch, Thomas A1 - Nipkau, Jens T1 - Forced Response Analysis of a Mistuned Compressor Blisk T2 - ASME Turbo Expo 2013: Turbine Technical Conference and Exposition, San Antonio, Texas, USA, June 3–7, 2013, Vol. 7B, Structures and Dynamics, Paper GT2013-94142 N2 - The forced response of an E3E-type 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 inter-blade 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 - Compressors KW - Blades KW - Blisks KW - Mistuning Y1 - 2013 UR - http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=1776795 SN - 978-0-7918-5527-0 U6 - https://doi.org/10.1115/GT2013-94142 PB - ASME CY - New York 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 - Maywald, Thomas A1 - Kühhorn, Arnold T1 - Mistuning and Damping Analysis of a Radial Turbine Blisk in Varying Ambient Conditions T2 - ASME Turbo Expo 2014: Turbine Technical Conference and Exposition, Volume 7B: Structures and Dynamics Düsseldorf, Germany, June 16–20, 2014, Paper GT2014-25521 N2 - A mistuned radial turbine impeller is analyzed with respect to the impact of varying ambient pressures and temperatures as well on frequency response functions and modal damping ratios. Beginning at room conditions, a finite element model of an impeller wheel at rest is updated based on experimentally determined mistuning in terms of blade dominated frequencies. The following numerical forced response analyses yield a maximum blade displacement amplification of 67% compared to the tuned reference. In addition, modal damping ratios are determined in dependence on the ambient pressure ranging from technical vacuum at 1 mbar up to 6000 mbar in a pressure chamber. Shaker excitation and laser Doppler vibrometry response measurement is employed in this context. A linear dependence of modal damping ratios on ambient pressure and a dominating damping contribution of the surrounding air even for higher modes could be proved. Moreover, the experimental determination of frequency response functions (FRF) at technical vacuum yields a better separation of resonance peaks compared to room conditions at 1013 mbar and hence, this data allows for more accurate model-updates in principle. It is proved that numerical models updated regarding mistuning at room conditions are well suited to predict the forced response at arbitrary pressures if measured modal damping ratios at these pressures are considered. Finally, within analyzing the effect of increasing structural temperatures with the surrounding air at 1013 mbar included slightly decreasing resonance frequencies but strongly increasing FRF-amplitudes are determined. Copyright © 2014 by ASME KW - Damping KW - Turbines Y1 - 2014 SN - 978-0-7918-4577-6 U6 - https://doi.org/10.1115/GT2014-25521 PB - ASME ER - TY - CHAP A1 - Beirow, Bernd A1 - Kühhorn, Arnold A1 - Giersch, Thomas A1 - Nipkau, Jens T1 - Optimization-Aided Forced Response Analysis of a Mistuned Compressor Blisk T2 - ASME Turbo Expo 2014, Turbine Technical Conference and Exposition, Volume 7B: Structures and Dynamics, Düsseldorf, Germany, June 16–20, 2014, Paper GT2014-25915 N2 - The forced response of the first rotor of an E3E-type high pressure compressor blisk is analyzed with regard to varying mistuning, varying engine order excitations and the consideration of aeroelastic effects. For that purpose, 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 technique is employed to model aeroelastic 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 aeroelastic 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 inter-blade 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. Copyright © 2014 by Rolls-Royce Deutschland Ltd & Co KG Y1 - 2014 SN - 978-0-7918-4577-6 U6 - https://doi.org/10.1115/GT2014-25915 PB - ASME ER - TY - GEN A1 - Maywald, Thomas A1 - Beirow, Bernd A1 - Kühhorn, Arnold T1 - Mistuning und Dämpfung von Radialturbinenrädern T2 - MTZ - Motortechnische Zeitschrift N2 - Moderne Verbrennungskraftmaschinen müssen ein stetig wachsendes Anforderungsprofil in Bezug auf Wirtschaftlichkeit, Leistung und Umweltfreundlichkeit erfüllen. In diesem Zusammenhang hat die Turboaufladung von Verbrennungsmotoren an Bedeutung gewonnen. Bei Turboladern kleiner und mittlerer Baugröße, deren Turbinen einen Durchmesser zwischen 30 und 250 mm aufweisen, kommen vornehmlich gegossene Laufräder zum Einsatz. Am Institut für Verkehrstechnik der Brandenburgischen Technischen Universität Cottbus-Senftenberg wurde im Rahmen eines FVV-Forschungsvorhabens der Einfluss charakteristischer Betriebsgrößen eines Turboladers auf das strukturdynamische Verhalten solcher Radialturbinenräder untersucht. Y1 - 2015 U6 - https://doi.org/10.1007/s35146-015-0043-7 SN - 2192-8843 VL - 76 IS - 06 SP - 68 EP - 75 ER - TY - CHAP A1 - Maywald, Thomas A1 - Beirow, Bernd A1 - Heinrich, Christoph Rocky A1 - Kühhorn, Arnold T1 - Vacuum Spin Test Series of a Turbine Impeller with Focus on Mistuning and Damping by Comparing Tip Timing and Strain Gauge Results T2 - ASME Turbo Expo 2015: Turbine Technical Conference and Exposition Volume 7B: Structures and Dynamics Montreal, Quebec, Canada, June 15–19, 2015 N2 - This paper describes preparation, execution and evaluation of a comprehensive bladed disk spin test series. At the example of an turbine impeller the effects of rotation and temperature are analyzed with special focus on mistuning and damping. The forced response is measured synchronously via 13 identical positioned strain gauges on each blade as well as via blade tip-timing. Subsequently it is possible to compare the results of both systems. During the test series rotational speed varies in the range from 10.000 up to 19.000 RPM. Simultaneously, the wheel is heated up to 820 K by an oven. A number of pre-selected natural frequencies, damping ratios and operating deflection shapes are evaluated and compared with respect to different rotational speeds and impeller temperatures. Copyright © 2015 by ASME KW - Rotation KW - Vacuum KW - Impellers KW - Damping KW - Turbines KW - Strain gages Y1 - 2015 SN - 978-0-7918-5677-2 U6 - https://doi.org/10.1115/GT2015-42649 PB - ASME CY - New York, NY ER - TY - CHAP A1 - Beirow, Bernd A1 - Kühhorn, Arnold A1 - Figaschewsky, Felix A1 - Nipkau, Jens T1 - Effect of Mistuning and Damping on the Forced Response of a Compressor Blisk Rotor T2 - ASME Turbo Expo 2015: Turbine Technical Conference and Exposition Volume 7A: Structures and Dynamics Montreal, Quebec, Canada, June 15–19, 2015 N2 - The forced response of an E3E-type high pressure compressor blisk front rotor is analyzed with regard to intentional mistuning and its robustness towards additional random mistuning. Both a chosen alternating mistuning pattern and artificial mistuning patterns optimized concerning the forced response are considered. Focusing on three different blade modes, subset of nominal system mode-based reduced order models are employed to compute the forced response. The disk remains unchanged while the Young’s modulus of each blade is used to define the particular mistuning pattern. The well established aerodynamic influence coefficient technique is employed to model aeroelastic coupling and hence to consider the strongly mode- and inter blade phase angle-dependent aerodynamic damping contribution. It has been found that a reduction of the maximum forced response beyond that of the tuned reference can be achieved for particular mistuning patterns and all modes considered. This implies an exciting engine order which would cause a low nodal diameter mode in case of a tuned blisk. At best a nearly 50% reduction of maximum response magnitudes is computed for the fundamental bending mode and large mistuning. The solution proved to be robust towards additional random mistuning of reasonable magnitude, which is of particular interest with regard to a potential technical realization. In case of small mistuning as assumed for the first torsion and the longitudinal bending mode the advantage of achieving response magnitudes beyond the tuned reference gets lost indeed, if random mistuning is superimposed. However, mostly a lower response level is calculated compared to responses obtained from models adjusted to mistuning determined by experiment. Copyright © 2015 by ASME KW - Compressors KW - Damping KW - Rotors Y1 - 2015 SN - 978-0-7918-5677-2 U6 - https://doi.org/10.1115/GT2015-42036 PB - ASME CY - New York, NY ER - TY - GEN A1 - Beirow, Bernd A1 - Maywald, Thomas A1 - Figaschewsky, Felix A1 - Kühhorn, Arnold A1 - Heinrich, Christoph Rocky A1 - Giersch, Thomas T1 - Simplified Determination of Aerodynamic Damping for Bladed Rotors, Part 1: Experimental Validation at Rest T2 - ASME Turbo Expo 2016, Turbomachinery Technical Conference and Exposition, Volume 7B, Structures and Dynamics, Seoul, South Korea, June 13–17, 2016 N2 - Considering both a radial turbine rotor of a turbocharger and an axial compressor test blisk at rest, aerodynamic damping characteristics are experimentally and numerically analyzed. Linear dependencies of modal damping ratios on the ambient pressure or the acoustic impedance, respectively, could be shown within experiments carried out inside a pressure chamber. The impact of the ambient air clearly dominates the modal damping ratios compared to the minor contribution of the structure. Assuming that acoustic emission can be regarded as main source of aerodynamic damping a simplified approach for its determination is introduced which only depends on natural frequency, mode shape and acoustic impedance. It is shown that a satisfying match between experiment and computation is achieved for those cases which are dedicated to sufficiently small ratios between wave lengths of acoustic emissions and blade distances. Y1 - 2016 SN - 978-0-7918-4984-2 U6 - https://doi.org/10.1115/GT2016-56535 N1 - Paper No. GT2016-56535 PB - ASME CY - New York, NY ER - TY - GEN A1 - Figaschewsky, Felix A1 - Kühhorn, Arnold A1 - Beirow, Bernd A1 - Giersch, Thomas A1 - Nipkau, Jens A1 - Meinl, Ferdinand T1 - Simplified Estimation of Aerodynamic Damping for Bladed Rotors, Part 2: Experimental Validation During operation T2 - ASME Turbo Expo 2016, Turbomachinery Technical Conference and Exposition, Volume 7B, Structures and Dynamics, Seoul, South Korea, June 13–17, 2016 N2 - Due to increasing requirements of future engine projects, much effort has been spent on the design of more efficient turbomachinery blades in the recent years. Besides aerodynamic efficiency constraints, these designs need to meet structural criteria ensuring that they are safe and robust with respect to High Cycle Fatigue (HCF). The estimation of the resonant vibration amplitude is done based on the aerodynamic force and the overall damping level. Since, for many applications the contribution of mechanical damping is often rather low compared to the aerodynamic counterpart, the determination of the aerodynamic damping is vital for the estimation of the forced vibration response. This second part is meant to contribute to a simplified computation of the aerodynamic damping during operation by making additional assumptions: The investigated mode family shall not suffer from flutter, has a high reduced frequency and the influence of adjacent blades is negligible. Under these circumstances a simplified approach can be introduced that allows for the computation of the mean value of the aerodynamic damping based on a steady state CFD solution of the regarded stage. It is well known, that the aerodynamic damping of a blade mode family depends on the inter blade phase angle (IBPA) and its direction of propagation, which is not covered by the simplified approach. For higher modes the difference between the minimum and maximum damping is often low and the mean value is a good approximation, whereas for fundamental modes there is often a significant difference. However, it is shown that considering a mistuned vibration response of the rotor, the expected value of the mistuned damping exhibits the mean value of IBPA-dependent aerodynamic damping. CFD simulations of an oscillating airfoil indicate a certain validity range of the simplified approach based on a modified reduced frequency and inlet Mach number, which allows to determine for which industrial applications the approach is most suitable. Finally, this range of validity is verified with experimentally determined overall damping values from strain gauge measurements during operation for 2 different industrial applications, an axial compressor stage of a jet engine and a radial turbine stage of a turbocharger. Copyright © 2016 by Rolls-Royce Deutschland Ltd & Co KG Y1 - 2016 SN - 978-0-7918-4984-2 U6 - https://doi.org/10.1115/GT2016-56458 N1 - Paper No. GT2016-56458 PB - ASME CY - New York, NY [u.a.] 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 - Figaschewsky, Felix A1 - Beirow, Bernd A1 - Kühhorn, Arnold A1 - Nipkau, Jens A1 - Giersch, Thomas A1 - Powers, Bronwyn T1 - Design and Analysis of an Intentional Mistuning Experiment Reducing Flutter Susceptibility and Minimizing Forced Response of a Jet Engine Fan T2 - ASME Turbo Expo 2017, GT2017-64621, June 26-30, 2017, Charlotte, NC, USA, Volume 7B N2 - Recent demands for a reduction of specific fuel consumption of jet engines have been opposed by increasing propulsive efficiency with higher bypass ratios and increased engine sizes. At the same time the challenge for the engine development is to design safe and efficient fan blades of high aspect ratios. Since the fan is the very first rotor stage, it experiences significant distortions in the incoming flow depending on the operating conditions. Flow distortions do not only lead to a performance and stall margin loss but also to remarkable low engine order (LEO) excitation responsible for forced vibrations of fundamental modes. Additionally, fans of jet engines typically suffer from stall flutter, which can be additionally amplified by reflections of acoustic pressure waves at the intake. Stall flutter appears before approaching the stall line on the fan’s characteristic and limits its stable operating range. Despite the fact that this “flutter bite” usually affects only a very narrow speed range, it reduces the overall margin of safe operation significantly. With increasing aspect ratios of ultra-high bypass ratio jet engines the flutter susceptibility will probably increase further and emphasizes the importance of considering aeromechanical analyses early in the design phase of future fans. This paper aims at proving that intentional mistuning is able to remove the flutter bite of modern jet engine fans without raising issues due to heavily increased forced vibrations induced by LEO excitation. Whereas intentional mistuning is an established technology in mitigating flutter, it is also known to amplify the forced response. However, recent investigations considering aeroelastic coupling revealed that under specific circumstances mistuning can also reduce the forced response due to engine order excitation. In order to allow a direct comparison and to limit costs as well as effort at the same time, the intentional mistuning is introduced in a non-destructive way by applying heavy paint to the blades. Its impact on the blade’s natural frequencies is estimated via finite element models with an additional paint layer. In parallel, this procedure is experimentally verified with painted fan blades in the laboratory. A validated SNM (subset of nominal system modes) representation of the fan is used as a computational model to characterize its mistuned vibration behavior. Its validation is done by comparing mistuned mode shape envelopes and frequencies of an experimental modal analysis at rest with those obtained by the updated computational model. In order to find a mistuning pattern minimizing the forced response of mode 1 and 2 at the same time and satisfying stability and imbalance constraints, a multi-objective optimization has been carried out. Finally, the beneficial properties of the optimized mistuning pattern are verified in a rig test of the painted rotor. Copyright © 2017 by Rolls-Royce Deutschland Ltd & Co KG KW - Flutter (Aerodynamics) KW - Desin KW - Jet engines Y1 - 2017 SN - 978-0-7918-5093-0 U6 - https://doi.org/10.1115/GT2017-64621 PB - ASME CY - New York, NY 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 - ASME Turbo Expo 2017, GT2017-63193, June 26-30, 2017, Charlotte, NC, USA, Volume 7B 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. Copyright © 2017 by ASME KW - Turbines KW - Modal Analysis Y1 - 2017 SN - 978-0-7918-5093-0 U6 - https://doi.org/10.1115/GT2017-63193 PB - ASME CY - New York, NY 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 -