@article{WeberBorchseniusDistletal., author = {Weber, Felix and Borchsenius, Fredrik and Distl, Johann and Braun, Christian}, title = {Performance of Numerically Optimized Tuned Mass Damper with Inerter (TMDI)}, series = {Applied Sciences}, volume = {12}, journal = {Applied Sciences}, number = {12}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/app12126204}, pages = {1 -- 15}, abstract = {In recent years, the Tuned Mass Damper with inerter (TMDI) has received significant attention. The inerter is defined to exert a force that is in proportion to the relative acceleration of the two inerter terminals. Here, two TMDI topologies are investigated. The conventional topology is given by the inerter being in parallel to the spring and viscous damper of the TMDI. The other topology is the serial arrangement of spring, inerter and viscous damper being in parallel to the stiffness of the mass spring oscillator of the TMDI. While the first topology intends to increase the inertial force of the TMDI, the second topology aims at producing an additional degree of freedom. The considered TMDI concepts are simulated for harmonic and random excitations, with parameters set according to those described in the literature and with numerically optimized parameters which minimize the primary structure displacement response. The classical TMD is used as a benchmark. The findings are twofold. The conventional TMDI with typical inertance ratio of 1\% and the very small value of 0.02\% performs significantly worse than the classical TMD with the same mass ratio. In contrast, the TMDI with an additional degree of freedom can improve the mitigation of the primary structure if the inertance ratio is set very small and if the TMDI parameters are numerically optimized.}, language = {en} } @article{WeberHuberBorchseniusetal.2020, author = {Weber, Felix and Huber, Peter and Borchsenius, Fredrik and Braun, Christian}, title = {Performance of TMDI for Tall Building Damping}, series = {Actuators}, volume = {9}, journal = {Actuators}, number = {4}, publisher = {MPDI}, doi = {10.3390/act9040139}, pages = {1 -- 13}, year = {2020}, abstract = {This study investigates the vibration reduction of tall wind-excited buildings using a tuned mass damper (TMD) with an inerter (TMDI). The performance of the TMDI is computed as a function of the floor to which the inerter is grounded as this parameter strongly influences the vibration reduction of the building and for the case when the inerter is grounded to the earth whereby the absolute acceleration of the corresponding inerter terminal is zero. Simulations are made for broadband and harmonic excitations of the first three bending modes, and the conventional TMD is used as a benchmark. It is found that the inerter performs best when grounded to the earth because, then, the inerter force is in proportion to the absolute acceleration of only the pendulum mass, but not to the relative acceleration of the two inerter terminals, which is demonstrated by the mass matrix. However, if the inerter is grounded to a floor below the pendulum mass, the TMDI only outperforms the TMD if the inerter is grounded to a floor within approximately the first third of the building's height. For the most realistic case, where the inerter is grounded to a floor in the vicinity of the pendulum mass, the TMDI performs far worse than the classical TMD.}, language = {en} } @inproceedings{TahedlBorchseniusTaras, author = {Tahedl, Michael and Borchsenius, Fredrik and Taras, Andreas}, title = {Efficient earthquake simulation of stiff and high DOF bridge expansion joint models with Python}, series = {Proceedings of the 10th ECCOMAS Thematic Conference on MULTIBODY DYNAMICS: December 12-15, 2021, Budapest, Hungary}, booktitle = {Proceedings of the 10th ECCOMAS Thematic Conference on MULTIBODY DYNAMICS: December 12-15, 2021, Budapest, Hungary}, publisher = {Budapest University of Technology and Economics}, address = {Budapest, HU}, isbn = {978-963-421-870-8}, doi = {10.3311/ECCOMASMBD2021-196}, pages = {172 -- 183}, abstract = {Various types of seismic protection devices has been developed to protect structures like bridges from collapse during an earthquake event, such as hydraulic or metallic hysteresis dampers and spherical pendulum bearings. The expansion joints however, which are already included in most large-span bridges, are not considered as an earthquake protection device regardless of the significant friction forces they produce. These friction forces can be seen as damping forces between the shaking environment and the oscillating bridge. To investigate the effect of those damping forces during different earthquake loads, a multibody dynamics simulation model of the expansion joints will be created. This model should be accurate enough to represent the generation of the damping forces and effects of the geometric setup of the expansion joints. Because large expansion joints for large-span bridges are of special interest, the number of degrees of freedom (DOF) becomes very high. Because this models include stiff bushings, implicit solvers need to be used to gain a stable simulation. Expansion joints are almost unique constructions for every specific bridge, which requires a automated model generation. Because of its excellent modules for numerical mathematics, the scripting language Python is used. To create an efficient simulation model, several optimization techniques such as Just-In-Time (JIT) compilation and parallelization are implemented and tested.}, language = {en} } @book{RillSchaefferBorchsenius, author = {Rill, Georg and Schaeffer, Thomas and Borchsenius, Fredrik}, title = {Grundlagen und computergerechte Methodik der Mehrk{\"o}rpersimulation}, publisher = {Springer Nature}, doi = {10.1007/978-3-658-41968-4}, pages = {XIV, 260}, abstract = {Dieses Lehr- und {\"U}bungsbuch vermittelt auf anschauliche Weise die Methoden der Mehrk{\"o}rpersimulation und verdeutlicht deren Vor- und Nachteile bei der praktischen Anwendung anhand konkreter Beispiele. Die einzelnen Methoden werden durch Matlab-Skripte und -Funktionen verdeutlicht, wobei die Modellbildung, die mathematische Beschreibung und die numerische Simulation von Systemen starrer K{\"o}rper die Schwerpunkte bilden. Die vorliegende Auflage wurde unter anderem um Matlab-Live-Skripte erweitert, welche kleine Animationen zur Veranschaulichung der Dynamik der Probleme enthalten. Die L{\"o}sungen zu den {\"U}bungsbeispielen und die integrierten Matlab-Skripte sowie weitere Beispiele und Anwendungen stehen {\"u}ber QR-Codes zum Download zur Verf{\"u}gung und erm{\"o}glichen dadurch auch ein effizientes Selbststudium.}, subject = {Mehrk{\"o}rpersystem}, language = {de} } @book{RillSchaefferBorchsenius, author = {Rill, Georg and Schaeffer, Thomas and Borchsenius, Fredrik}, title = {Grundlagen und computergerechte Methodik der Mehrk{\"o}rpersimulation}, edition = {4. Aufl.}, publisher = {Springer Fachmedien}, address = {Wiesbaden}, isbn = {978-3-658-28911-9}, doi = {10.1007/978-3-658-28912-6}, abstract = {Dieses Lehrbuch stellt die Methoden der Mehrk{\"o}rpersimulation anschaulich dar und erl{\"a}utert an einfachen Beispielen die Vor- und Nachteile bei der praktischen Anwendung. In den Text integrierte Matlab-Skripte und -Funktionen verdeutlichen die einzelnen Methoden. Die Modellbildung, die mathematische Beschreibung und die numerische Simulation von Systemen starrer K{\"o}rper bilden dabei die Schwerpunkte. Konkrete Beispiele beinhalten einen Bungee-Sprung, die Eigendynamik eines Traktors mit Vorderachsfederung, das Hubschrauberrotorblatt sowie eine Pkw-Vorderachse. Die L{\"o}sungen zu den {\"U}bungsaufgaben und die im Text integrierten Matlab-Beispiele, die zum Teil durch Animationen angereichert sind, sowie zus{\"a}tzliche Beispiele und Anwendungen stehen auf der Verlagshomepage beim Buch zum Download zur Verf{\"u}gung und erm{\"o}glichen dadurch auch ein effizientes Selbststudium.}, language = {de} } @incollection{RillSchaefferBorchsenius, author = {Rill, Georg and Schaeffer, Thomas and Borchsenius, Fredrik}, title = {Analyse von Mehrk{\"o}rpersystemen}, series = {Grundlagen und computergerechte Methodik der Mehrk{\"o}rpersimulation}, booktitle = {Grundlagen und computergerechte Methodik der Mehrk{\"o}rpersimulation}, publisher = {Springer}, doi = {10.1007/978-3-658-41968-4_5}, pages = {198}, abstract = {Nach dem Aufbau eines Mehrk{\"o}rper-Simulationsmodells muss dieses auf Richtigkeit, Funktionalit{\"a}t und Wirtschaftlichkeit getestet werden. Die Ermittlung der Gleichgewichtslage stellt dabei eine erste Plausibilit{\"a}ts-Kontrolle dar. Eine Linearisierung mit anschließender Analyse der Eigendynamik liefert Aussagen {\"u}ber die Frequenzen und das D{\"a}mpfungsverhalten des Modells. Einfache Erregersignale erm{\"o}glichen einen ersten Einblick in das nichtlineare dynamische Verhalten des Modells. Modell-Parameter, die nicht genau bekannt sind, k{\"o}nnen durch gezielte Variationen plausibel gesch{\"a}tzt oder {\"u}ber eine Optimierung sogar mit optimalen Werten belegt werden. Nach all diesen Tests steht das Mehrk{\"o}rper- Simulationsmodell dann f{\"u}r praktischeUntersuchungen zurVerf{\"u}gung, die neben reinen Zeitsimulationen auch Methoden der Inversen Kinematik und der Inversen Dynamik mit einschließen.}, language = {de} }