@inproceedings{MichaelisMarburgRetka, author = {Michaelis, Thomas and Marburg, Steffen and Retka, Stefanie}, title = {Application of the Transfer Path Analysis to Vehicle Doors}, series = {INTER-NOISE and NOISE-CON Congress and Conference Proceedings, Glasgow}, volume = {265}, booktitle = {INTER-NOISE and NOISE-CON Congress and Conference Proceedings, Glasgow}, number = {4}, publisher = {Institute of Noise Control Engineering}, doi = {10.3397/IN_2022_0551}, pages = {3878 -- 3885}, abstract = {Transfer path analysis (TPA) is a proven method for identifying critical structure-borne and airborne sound paths. The basic idea is to divide the overall system into an exciting active component (source) and a passive component, e.g. the mechanical structure to be investigated, with their respective measurement points. By separating them, two independent systems are created, whereby on one hand, the excitation behaviour can be characterised and on the other hand, the transmission behaviour can be assessed. Finally, both systems are validated by comparing them to each other and deciding whether changes to source or structure are required or not. The advantage is the simple description of the source as a black box without complex modelling. In this contribution, this systematic is applied to window regulator systems as they are found in vehicles. The focus is on a hybrid approach between experimental and numerical transfer path analysis. For this purpose, the basic workflow of suitable TPA methods is discussed. This includes the operational measurement of different exciting electric motors variants, the determination of the transfer functions of the structure, the calculation of the contact forces and the analysis of the individual transfer paths.}, language = {en} } @inproceedings{ChackoRetka, author = {Chacko, Jain and Retka, Stefanie}, title = {Genetic algorithm for the optimization of damping material}, series = {INTER-NOISE and NOISE-CON Congress and Conference Proceedings, Glasgow}, volume = {265}, booktitle = {INTER-NOISE and NOISE-CON Congress and Conference Proceedings, Glasgow}, number = {4}, publisher = {Institute of Noise Control Engineering}, doi = {10.3397/IN_2022_0492}, pages = {3456 -- 3463}, abstract = {A main research topic in acoustics is the reduction of indoor noise, which has increasingly received attention in recent years. A commonly used solution to solve these problems is reducing noise using damping structures, which absorb sound. This work aims at the numerical optimization of damping structures in interior problems, following three goals. First, the optimal damping structure for the required frequency range has to be determined. Second, the optimal position of the damping material has to be found. Third, we are focusing on lightweight design, which means that the amount of damping material used, has to be kept to a minimum. We present the implementation of a genetic algorithm into our open source code, which we use to optimize the damping behaviour and in consequence, the sound propagation for interior problems. We show an example of the application of this code.}, language = {en} } @inproceedings{CelikRiessPolsteretal., author = {Celik, Ertac and Riess, Julia and Polster, Christian and Helwich, Vadim and Retka, Stefanie}, title = {Entwicklung eines Versuchsstandes zur Ger{\"a}uschuntersuchung am Fahrradkettentrieb}, series = {Fortschritte in der Akustik - Plenarvortr{\"a}ge und Fachbeitr{\"a}ge der 49. Jahrestagung f{\"u}r Akustik, Hamburg}, booktitle = {Fortschritte in der Akustik - Plenarvortr{\"a}ge und Fachbeitr{\"a}ge der 49. Jahrestagung f{\"u}r Akustik, Hamburg}, pages = {809 -- 811}, language = {de} } @inproceedings{MichaelisMarburgRetka, author = {Michaelis, Thomas and Marburg, Steffen and Retka, Stefanie}, title = {D{\"a}mpfungsidentifikation von Leichtbaustrukturen}, series = {Fortschritte in der Akustik - Plenarvortr{\"a}ge und Fachbeitr{\"a}ge der 49. Jahrestagung f{\"u}r Akustik, Hamburg}, booktitle = {Fortschritte in der Akustik - Plenarvortr{\"a}ge und Fachbeitr{\"a}ge der 49. Jahrestagung f{\"u}r Akustik, Hamburg}, pages = {1338 -- 1341}, language = {de} } @inproceedings{MichaelisMarburgRetka, author = {Michaelis, Thomas and Marburg, Steffen and Retka, Stefanie}, title = {Transferpfadanalyse von Fensterhebersystemen}, series = {Fortschritte in der Akustik - Plenarvortr{\"a}ge und Fachbeitr{\"a}ge der 48. Jahrestagung f{\"u}r Akustik, Stuttgart}, booktitle = {Fortschritte in der Akustik - Plenarvortr{\"a}ge und Fachbeitr{\"a}ge der 48. Jahrestagung f{\"u}r Akustik, Stuttgart}, pages = {447 -- 450}, language = {de} } @inproceedings{MichaelisRetka, author = {Michaelis, Thomas and Retka, Stefanie}, title = {Anwendung der parametrischen Modellordnungsreduktion in der Vibroakustik}, series = {Fortschritte in der Akustik - Plenarvortr{\"a}ge und Fachbeitr{\"a}ge der 47. Jahrestagung f{\"u}r Akustik, Wien}, booktitle = {Fortschritte in der Akustik - Plenarvortr{\"a}ge und Fachbeitr{\"a}ge der 47. Jahrestagung f{\"u}r Akustik, Wien}, pages = {892 -- 895}, language = {de} } @inproceedings{RetkaCelik, author = {Retka, Stefanie and Celik, Ertac}, title = {Entwicklung eines Praktikumsversuchs zur Luftschallmessung nach DIN}, series = {Fortschritte in der Akustik - Plenarvortr{\"a}ge und Fachbeitr{\"a}ge der 48. Jahrestagung f{\"u}r Akustik, Stuttgart}, booktitle = {Fortschritte in der Akustik - Plenarvortr{\"a}ge und Fachbeitr{\"a}ge der 48. Jahrestagung f{\"u}r Akustik, Stuttgart}, pages = {679 -- 681}, language = {de} } @article{SpeschaWeikertRetkaetal., author = {Spescha, Daniel and Weikert, Sascha and Retka, Stefanie and Wegener, Konrad}, title = {Krylov and Modal Subspace based Model Order Reduction with A-Priori Error Estimation}, series = {ETH Z{\"u}rich - Research Collection}, journal = {ETH Z{\"u}rich - Research Collection}, doi = {10.3929/ethz-b-000284435}, pages = {25}, abstract = {Versatile model order reduction techniques for the reduction of dynamic systems have been presented in the last decades. Krylov subspace based methods are considered as efficient in terms of computational effort and reduction order and can be used in order to match the transfer function locally. However, they lack of a simple and efficient automatisation and error estimation. On the other hand, modal reduction is popular because it leads to exactly matching eigenfrequencies. The static behaviour and the overall accuracy of the frequency response, though, are poor. In this paper, a combination of both methods is presented and discussed. In order to characterise a method for the reduction of mechanical models for the simulation of machine tools and similar mechatronic systems, first, the requirements on the model reduction method are derived. Criteria for the relative error of the frequency response function, the transmission zeros, and the poles are defined and the idea of defining a frequency range of interest is established. Subsequently, a combination of Krylov and modal subspaces for the reduction of dynamic systems with second-order structure and proportional damping is presented. It is shown that the combination of the bases of the two methods leads to a combination of the advantages and an elimination of the drawbacks of them both. Moreover, an estimation for the upper bound of the defined error criteria is developed and verified with numerical results. The result of this paper is an a priori parametrisable and numerically efficient model reduction method, which leads to reduced systems of low order with a definable error limit within a definable frequency range.}, language = {en} } @inproceedings{HahnFleischerRetka, author = {Hahn, Pascal and Fleischer, Mario and Retka, Stefanie}, title = {Numerische Modellierung der Schallausbreitung im menschlichen Vokaltrakt}, series = {Fortschritte in der Akustik - Plenarvortr{\"a}ge und Fachbeitr{\"a}ge der 46. Jahrestagung f{\"u}r Akustik, Hannover}, booktitle = {Fortschritte in der Akustik - Plenarvortr{\"a}ge und Fachbeitr{\"a}ge der 46. Jahrestagung f{\"u}r Akustik, Hannover}, pages = {708 -- 711}, language = {de} } @inproceedings{HahnRetka, author = {Hahn, Pascal and Retka, Stefanie}, title = {Einfluss der absorbierenden akustischen Leistung auf die Eigenschaften von Resonanzfrequenzen}, series = {Fortschritte in der Akustik - Plenarvortr{\"a}ge und Fachbeitr{\"a}ge der 47. Jahrestagung f{\"u}r Akustik, Wien}, booktitle = {Fortschritte in der Akustik - Plenarvortr{\"a}ge und Fachbeitr{\"a}ge der 47. Jahrestagung f{\"u}r Akustik, Wien}, pages = {900 -- 903}, language = {de} } @inproceedings{MichaelisMarburgRetka, author = {Michaelis, Thomas and Marburg, Steffen and Retka, Stefanie}, title = {D{\"a}mpfungsidentifikation von Leichtbaustrukturen}, editor = {Deutsche Gesellschaft f{\"u}r Akustik e.V. (DEGA),}, publisher = {DAGA - 49. Jahrestagung f{\"u}r Akustik}, isbn = {978-3-939296-21-8}, pages = {1338-1341}, abstract = {Leichtbaustrukturen kommen in vielen Branchen und Bereichen zum Einsatz. Vor allem der Fahrzeugbau sowie die Luft- und Raumfahrt profitieren von dem geringen Materialeinsatz und der Einsparung in der Nutzungsphase. Neben den genannten Potenzialen bieten Leichtbaustrukturen die M{\"o}glichkeit, gezielt eine hohe D{\"a}mpfung von Vibrationen bei geringem Materialeinsatz zu kombinieren. In diesem Zusammenhang werden h{\"a}ufig sog. Sandwichstrukturen verwendet. Die Sandwichstrukturen bestehen in der Regel aus kraftaufnehmenden Deckschichten und weicheren Kernschichten aus einer Wabenstruktur oder Vollmaterial aus Kunststoffen. Letztere {\"u}bernehmen h{\"a}ufig die Aufgabe der D{\"a}mpfung. In diesem Beitrag wird die D{\"a}mpfung einer ebenen Sandwichstruktur bestehend aus einer metallischen Deckschicht und einer viskoelastischen Polymerschicht untersucht. Die Herausforderung liegt in der physikalischen Modellierung der Materiald{\"a}mpfung sowie der {\"U}bertragung der experimentell gewonnenen Daten in ein Finite-Elemente Simulationsmodell. Hierzu werden bestehende Methoden der D{\"a}mpfungsidentifikation evaluiert. Anschließend wird die Struktur mithilfe einer experimentellen Schwingungsanalyse unter vorgegebenen Randbedingungen analysiert. Aus den gewonnenen Messdaten werden Parameter ermittelt, um ein frequenzabh{\"a}ngiges Materialmodell zu generieren. Neben dem Vergleich der experimentellen und berechneten Ergebnisse liegt der Schwerpunkt dieses Beitrags auf der Betrachtung von Unsicherheiten w{\"a}hrend des Prozesses.}, language = {de} }