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 - 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 - GEN A1 - Beirow, Bernd A1 - Kühhorn, Arnold A1 - Figaschewsky, Felix A1 - Bornholm, Alfons T1 - Vibration analysis of a mistuned axial turbine blisk T2 - ASME Turbo Expo 2019: Turbomachinery Technical Conference and Exposition, June 17–21, 2019, Phoenix, Arizona, USA N2 - An axial turbine blisk for turbocharger applications is analyzed with respect to the effect of intentional mistuning on the forced response. Originally, the intentional mistuning pattern has been designed by employing a genetic algorithm optimization in order to reduce the forced response caused by low engine order excitation (LEO) of the fundamental flap mode. The solution found has been implemented in a prototype of that blisk. For the purpose of comparison, a second reference blisk has been manufactured without intentional mistuning. The actual mistuning distributions of the blisks have been identified by employing blade-by-blade impact testing. Alternatively, a new inverse approach has been employed, which is based on a least squares formulation and benefits from less experimental effort. Based on the information gained by the aforementioned testing procedures, subset of nominal systems (SNM)-models have been updated, which allow for considering the aeroelastic coupling by means of aerodynamic influence coefficients (AIC). Despite of small but unavoidable deviations from the design intention it could be proved within numerical simulations that the intended 70 per cent reduction of the maximum forced response is nevertheless achieved. In addition, the paper is addressing the effect of the aforementioned intentional mistuning pattern on a higher mode, which is relevant for the durability as well. Hence, new SNM-models have to be updated in order to calculate the forced response due to EO-excitation caused by the nozzle guide vane. Although the original mistuning pattern has been optimized solely for reducing the forced response of the fundamental flap mode, it hardly affects the higher mode forced response in a negative manner. KW - Turbines KW - Vibration analysis KW - Blades KW - Excitation KW - Computer simulation KW - Design Y1 - 2019 UR - https://asmedigitalcollection.asme.org/GT/GT2019/volume/58691 SN - 978-0-7918-5869-1 U6 - https://doi.org/10.1115/GT2019-92047 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 -