@inproceedings{KoberKuehhornKaestneretal., author = {Kober, Markus and K{\"u}hhorn, Arnold and K{\"a}stner, Benjamin and Keskin, Akin}, title = {Evaluation of the Stress and Displacement Behavior of Different LS-Dyna Element Types in Combination with Different Anti-Hourglassing Formulations and Initial Element Deformations}, series = {Kurzfassungen der Vortr{\"a}ge, 13. LS-DYNA Forum 2014, 6. - 8. Oktober 2014, Bamberg}, booktitle = {Kurzfassungen der Vortr{\"a}ge, 13. LS-DYNA Forum 2014, 6. - 8. Oktober 2014, Bamberg}, publisher = {DYNAmore GmbH}, address = {Stuttgart}, isbn = {978-3-9816215-1-8}, language = {en} } @inproceedings{KoberKuehhornStelldingeretal., author = {Kober, Markus and K{\"u}hhorn, Arnold and Stelldinger, Enrico and Keskin, Akin}, title = {Identification of Stiffness Parameters of a Simplified Aero-Engine Mount System by Using a Higher Fidelity Model of the Mount System}, series = {Kurzfassungen der Vortr{\"a}ge, 13. LS-DYNA Forum 2014, 6. - 8. Oktober 2014, Bamberg}, booktitle = {Kurzfassungen der Vortr{\"a}ge, 13. LS-DYNA Forum 2014, 6. - 8. Oktober 2014, Bamberg}, publisher = {DYNAmore GmbH}, address = {Stuttgart}, isbn = {978-3-9816215-1-8}, language = {en} } @misc{KoberKuehhornRademannetal., author = {Kober, Markus and K{\"u}hhorn, Arnold and Rademann, J{\"o}rg and M{\"u}ck, Bernhard}, title = {Nonlinear topology optimization of centrifugally loaded aero-engine part with newly developed optimality-criteria based algorithm}, series = {Aerospace Science and Technology}, volume = {Vol. 39}, journal = {Aerospace Science and Technology}, doi = {10.1016/j.ast.2014.09.005}, pages = {705 -- 711}, abstract = {In this paper a successful topology optimization of a centrifugally loaded aero-engine part is presented. For the topology optimization, which is a nonlinear problem due to several contact regions, a self-developed topology optimization algorithm in combination with a commercial FE-solver is used. The goal of the optimization was the reduction of stresses in the structure. ©2014 Rolls-Royce Deutschland Ltd \& Co. KG. Published by Elsevier Masson SAS. All rights reserved.}, language = {en} } @misc{MaywaldBeirowKuehhorn, author = {Maywald, Thomas and Beirow, Bernd and K{\"u}hhorn, Arnold}, title = {Mistuning und D{\"a}mpfung von Radialturbinenr{\"a}dern}, series = {MTZ - Motortechnische Zeitschrift}, volume = {76}, journal = {MTZ - Motortechnische Zeitschrift}, number = {06}, issn = {2192-8843}, doi = {10.1007/s35146-015-0043-7}, pages = {68 -- 75}, abstract = {Moderne Verbrennungskraftmaschinen m{\"u}ssen ein stetig wachsendes Anforderungsprofil in Bezug auf Wirtschaftlichkeit, Leistung und Umweltfreundlichkeit erf{\"u}llen. In diesem Zusammenhang hat die Turboaufladung von Verbrennungsmotoren an Bedeutung gewonnen. Bei Turboladern kleiner und mittlerer Baugr{\"o}ße, deren Turbinen einen Durchmesser zwischen 30 und 250 mm aufweisen, kommen vornehmlich gegossene Laufr{\"a}der zum Einsatz. Am Institut f{\"u}r Verkehrstechnik der Brandenburgischen Technischen Universit{\"a}t Cottbus-Senftenberg wurde im Rahmen eines FVV-Forschungsvorhabens der Einfluss charakteristischer Betriebsgr{\"o}ßen eines Turboladers auf das strukturdynamische Verhalten solcher Radialturbinenr{\"a}der untersucht.}, language = {de} } @misc{StelldingerKuehhornKober, author = {Stelldinger, Enrico and K{\"u}hhorn, Arnold and Kober, Markus}, title = {Experimental evaluation of the low-velocity impact damage resistance of CFRP tubes with integrated rubber layer}, series = {Composite Structures}, journal = {Composite Structures}, number = {139}, issn = {0263-8223}, doi = {10.1016/j.compstruct.2015.11.069}, pages = {30 -- 35}, abstract = {The impact performance of structural components made of fibre-reinforced plastic is often one of the limiting properties during the design process. To improve the damage resistance regarding transverse low-velocity impact loading, a rubber layer (KRAIBON®) is integrated into the composite laminate of tubular carbon/epoxy specimens. Numerous impact tests, using two different rubber compounds and three different layups, are carried out. The specimens are impacted using a modified Charpy pendulum. Force-time histories have been used to determine the damage threshold load. To visualise damage such as delaminations and inter-fibre failures, the impacted samples have been examined using microsectioning. It is shown that a significant improvement in impact damage resistance can be achieved by integrating a rubber layer into a carbon/epoxy laminate.}, language = {en} } @misc{KoberKuehhornMueck, author = {Kober, Markus and K{\"u}hhorn, Arnold and M{\"u}ck, Bernhard}, title = {Topologieoptimierung eines fliehkraftbelasteten Triebwerkbauteils mit einfach zu implementierendem Algorithmus unter Ber{\"u}cksichtigung mehrerer Zielfunktionen}, series = {NAFEMS-Magazin : Zeitschrift f{\"u}r numerische Simulationsmethoden und angrenzende Gebiete}, journal = {NAFEMS-Magazin : Zeitschrift f{\"u}r numerische Simulationsmethoden und angrenzende Gebiete}, number = {35}, issn = {2311-522x}, pages = {56 -- 66}, language = {de} } @inproceedings{WagnerKuehhorn, author = {Wagner, Frank and K{\"u}hhorn, Arnold}, title = {Response surface based robust design optimization on the example of a high pressure turbine blade}, series = {8. Dresdner Probabilistik-Workshop, Technische Universit{\"a}t Dresden, 08.-09. Okt. 2015}, booktitle = {8. Dresdner Probabilistik-Workshop, Technische Universit{\"a}t Dresden, 08.-09. Okt. 2015}, address = {Dresden}, pages = {18}, abstract = {Nowadays in a product design process the manufacturing tolerances have to be considered. Therefore a deterministic optimization needs to be converted into a robust design optimization. Usually the reference geometry is represented by a parametric model and an appropriate set of default parameters. In the robust design approach this set is replaced by a set of distributed parameters. These distributions are known from a previous design or needs to be estimated. This work is about a robust design and multi objective optimization of a high pressure turbine blade (first row) from an actual aero engine. The multidisciplinary objectives are the combined life of the aero-foil (LCF and creep) for the outer and inner geometry, the efficiency and the mass of the blade. For the input set different kinds of parameter will be examined. Apart from the major geometry parameters, which represent the external surface of the blade, parameters for material and boundary conditions will be investigated as well. The used workflow contains the Rolls-Royce tool parablading for the creation of the external aero-foil, Siemens NX for general geometry manipulation, Hydra as Navier-Stokes solver and SC03 for the structural problem and is set up in the automation software ISight. Focus of this work is the creation of response surfaces and physical integrity of the delivered results. Therefore, different validation criteria will be consulted. These are implemented in a Matlab toolbox and tested on typical optimization test problems. Based on the validated response surfaces a huge number of evaluations is possible, which is necessary for a robust design optimization. As the major result a set of Pareto optimal designs will be delivered.}, language = {en} } @inproceedings{GierschKuehhornFigaschewsky, author = {Giersch, Thomas and K{\"u}hhorn, Arnold and Figaschewsky, Felix}, title = {Probabilistic Analysis of Low Engine Order Excitation Due to Geometric Perturbations of Upstream Nozzle Guide Vanes : ISABE-2015-20165}, series = {Conference Proceedings from the 22nd International Symposium on Air Breathing Engines, October 25-30, 2015, Phoenix, Arizona}, booktitle = {Conference Proceedings from the 22nd International Symposium on Air Breathing Engines, October 25-30, 2015, Phoenix, Arizona}, publisher = {ISABE}, pages = {1 -- 9}, language = {en} } @inproceedings{FigaschewskyKuehhorn, author = {Figaschewsky, Felix and K{\"u}hhorn, Arnold}, title = {Analysis of Mistuned Blade Vibrations Based on Normally Distributed Blade Individual Natural Frequencies}, series = {ASME Turbo Expo 2015: Turbine Technical Conference and Exposition Volume 7B: Structures and Dynamics Montreal, Quebec, Canada, June 15-19, 2015}, booktitle = {ASME Turbo Expo 2015: Turbine Technical Conference and Exposition Volume 7B: Structures and Dynamics Montreal, Quebec, Canada, June 15-19, 2015}, publisher = {ASME}, address = {New York, NY}, isbn = {978-0-7918-5677-2}, doi = {10.1115/GT2015-43121}, abstract = {With increasing demands for reliability of modern turbomachinery blades the quantification of uncertainty and its impact on the designed product has become an important part of the development process. This paper aims to contribute to an improved approximation of expected vibration amplitudes of a mistuned rotor assembly under certain assumptions on the probability distribution of the blade's natural frequencies. A previously widely used lumped mass model is employed to represent the vibrational behavior of a cyclic symmetric structure. Aerodynamic coupling of the blades is considered based on the concept of influence coefficients leading to individual damping of the traveling wave modes. The natural frequencies of individual rotor blades are assumed to be normal distributed and the required variance could be estimated due to experiences with the applied manufacturing process. Under these conditions it is possible to derive the probability distribution of the off-diagonal terms in the mistuned equations of motions, that are responsible for the coupling of different circumferential modes. Knowing these distributions recent limits on the maximum attainable mistuned vibration amplitude are improved. The improvement is achieved due to the fact, that the maximum amplification depends on the mistuning strength. This improved limit can be used in the development process, as it could partly replace probabilistic studies with surrogate models of reduced order. The obtained results are verified with numerical simulations of the underlying structural model with random mistuning patterns based on a normal distribution of individual blade frequencies. Copyright © 2015 by ASME}, language = {en} } @inproceedings{MaywaldBeirowHeinrichetal., author = {Maywald, Thomas and Beirow, Bernd and Heinrich, Christoph Rocky and K{\"u}hhorn, Arnold}, title = {Vacuum Spin Test Series of a Turbine Impeller with Focus on Mistuning and Damping by Comparing Tip Timing and Strain Gauge Results}, series = {ASME Turbo Expo 2015: Turbine Technical Conference and Exposition Volume 7B: Structures and Dynamics Montreal, Quebec, Canada, June 15-19, 2015}, booktitle = {ASME Turbo Expo 2015: Turbine Technical Conference and Exposition Volume 7B: Structures and Dynamics Montreal, Quebec, Canada, June 15-19, 2015}, publisher = {ASME}, address = {New York, NY}, isbn = {978-0-7918-5677-2}, doi = {10.1115/GT2015-42649}, abstract = {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}, language = {en} }