2021
|
Schimmer, F.; Gebhardt, J.; Motsch-Eichmann, N.; Hausmann, J.; Ehrlich, I. The effect of curvature on the low-velocity impact resistance of CF/PEEK laminates Leichtbau Konferenzbeitrag In: 30 Years IVW Anniversary Colloquium, Leibnitz-Institut für Verbundwerkstoffe Kaiserslautern, 2021. @inproceedings{Schimmer2021,
title = {The effect of curvature on the low-velocity impact resistance of CF/PEEK laminates},
author = {F. Schimmer and J. Gebhardt and N. Motsch-Eichmann and J. Hausmann and I. Ehrlich},
year = {2021},
date = {2021-09-09},
booktitle = {30 Years IVW Anniversary Colloquium},
address = {Kaiserslautern},
organization = {Leibnitz-Institut für Verbundwerkstoffe},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
|
2020
|
Kastenmeier, A. Biegeverhalten faserverstärkter Kunststoffrohre unter Berücksichtigung einer mehrreihigen Bolzenverbindung Leichtbau Promotionsarbeit Universität der Bundeswehr München, Ostbayerische Technische Hochschule Regensburg, urn:nbn:de:bvb:706-7105, 2020. @phdthesis{Kastenmeier2020,
title = {Biegeverhalten faserverstärkter Kunststoffrohre unter Berücksichtigung einer mehrreihigen Bolzenverbindung},
author = {A. Kastenmeier},
editor = {Ehrlich, Ingo, Prof. Dr.-Ing.; Brünig, Michael, Univ.-Prof. Dr.-Ing. habil.; Gebbeken, Norbert, Univ.-Prof. Dr.-Ing. habil. },
url = {https://athene-forschung.unibw.de/135000
},
year = {2020},
date = {2020-12-10},
address = {Werner-Heisenberg-Weg 39, 85577 Neubiberg},
school = {Universität der Bundeswehr München, Ostbayerische Technische Hochschule Regensburg, urn:nbn:de:bvb:706-7105},
abstract = {In der vorliegenden Arbeit wird die Charakterisierung des mechanischen Verhaltens von auskragenden Rohren aus kohlenstofffaserverstärktem Kunststoff (CFK) mit Querkraftbelastung an einem Ende und einer mehrreihigen Bolzenverbindung am anderen Ende behandelt. Bolzenverbindungen mit Fügepartner aus CFK werden im Stand der Technik nur an ebenen, zug- oder druckbelasteten, Verbindungen untersucht, weshalb der Einfluss der Biegebelastung, der gekrümmten Auflageflächen und des geschlossenen Rohrprofils untersucht und qualifiziert wird. Zudem zeigt sich ein Effekt der Abstützung bzw. resultierenden Verformungsbehinderung. Die Grundlage der Untersuchungen bilden 2-Punkt-Biegeversuche mit Verzerrungs- und Verschiebungsmessungen, die über FE-Modelle numerisch abgebildet und in einer Verzerrungs- und Spannungsanalyse detaillierter ausgewertet werden. Zur Darstellung des Einflusses der Biegebelastung werden zudem reine Zug- und Drucklasten aufgebracht, ausgewertet und abgeglichen. In drei Variationen des Biegeversuchs werden zudem, sowohl experimentell als auch numerisch, Effekte zu einer möglichen Steigerung der Verbindungsfestigkeit untersucht. Dazu zählt die Verwendung von zusätzlichen Schichten aus Titanlegierung im Kraftüberleitungsbereich, ein Versetzen der Bolzen im Umfang und eine Änderung der Abstützung in Lastrichtung. Für das Biegeverhalten der CFK-Rohre im frei auskragenden Bereich werden kontinuumsmechanische Modelle der anisotropen Elastizität für Rohre unter reiner Biegebelastung beschrieben, adaptiert und bezüglich der Ergebnisse bewertet. Um die Vergleichbarkeit der Berechnungsmodelle und Versuche zu gewährleisten, wird einerseits der Einfluss der speziellen Schichtstruktur in gewickelten CFK-Rohren diskutiert und andererseits werden die transversal-isotropen Materialeigenschaften der Einzelschicht an Probekörpern aus den Rohren bestimmt. },
type = {Dissertation},
keywords = {},
pubstate = {published},
tppubtype = {phdthesis}
}
In der vorliegenden Arbeit wird die Charakterisierung des mechanischen Verhaltens von auskragenden Rohren aus kohlenstofffaserverstärktem Kunststoff (CFK) mit Querkraftbelastung an einem Ende und einer mehrreihigen Bolzenverbindung am anderen Ende behandelt. Bolzenverbindungen mit Fügepartner aus CFK werden im Stand der Technik nur an ebenen, zug- oder druckbelasteten, Verbindungen untersucht, weshalb der Einfluss der Biegebelastung, der gekrümmten Auflageflächen und des geschlossenen Rohrprofils untersucht und qualifiziert wird. Zudem zeigt sich ein Effekt der Abstützung bzw. resultierenden Verformungsbehinderung. Die Grundlage der Untersuchungen bilden 2-Punkt-Biegeversuche mit Verzerrungs- und Verschiebungsmessungen, die über FE-Modelle numerisch abgebildet und in einer Verzerrungs- und Spannungsanalyse detaillierter ausgewertet werden. Zur Darstellung des Einflusses der Biegebelastung werden zudem reine Zug- und Drucklasten aufgebracht, ausgewertet und abgeglichen. In drei Variationen des Biegeversuchs werden zudem, sowohl experimentell als auch numerisch, Effekte zu einer möglichen Steigerung der Verbindungsfestigkeit untersucht. Dazu zählt die Verwendung von zusätzlichen Schichten aus Titanlegierung im Kraftüberleitungsbereich, ein Versetzen der Bolzen im Umfang und eine Änderung der Abstützung in Lastrichtung. Für das Biegeverhalten der CFK-Rohre im frei auskragenden Bereich werden kontinuumsmechanische Modelle der anisotropen Elastizität für Rohre unter reiner Biegebelastung beschrieben, adaptiert und bezüglich der Ergebnisse bewertet. Um die Vergleichbarkeit der Berechnungsmodelle und Versuche zu gewährleisten, wird einerseits der Einfluss der speziellen Schichtstruktur in gewickelten CFK-Rohren diskutiert und andererseits werden die transversal-isotropen Materialeigenschaften der Einzelschicht an Probekörpern aus den Rohren bestimmt. |
Lindner, M.; Berndt, D.; Tschurtschenthal, K.; Ehrlich, I.; Jungbauer, B.; Schreiner, R.; Pipa, A. V.; Hink, R.; Brandenburg, R.; Neuwirth, D.; Karpen, N.; Bonaccurso, E.; Weichwald, R.; Max, A.; Caspari, R. Aircraft Icing Mitigation by DBD-based Micro Plasma Actuators Leichtbau Konferenzbeitrag In: AIAA AVIATION 2020 FORUM, 2020. @inproceedings{Lindner2020,
title = {Aircraft Icing Mitigation by DBD-based Micro Plasma Actuators},
author = {M. Lindner and D. Berndt and K. Tschurtschenthal and I. Ehrlich and B. Jungbauer and R. Schreiner and A. V. Pipa and R. Hink and R. Brandenburg and D. Neuwirth and N. Karpen and E. Bonaccurso and R. Weichwald and A. Max and R. Caspari},
url = {https://arc.aiaa.org/doi/10.2514/6.2020-3243},
doi = {10.2514/6.2020-3243},
year = {2020},
date = {2020-06-08},
publisher = {AIAA AVIATION 2020 FORUM},
abstract = {We present the application of plasma actuators as a technology for ice prevention at airfoils. The miniaturized dielectric barrier discharge (DBD) plasma actuators (PA) were fabricated by means of microelectromechanical systems (MEMS). We elucidate how to make the actuator samples scalable and applicable to any desired shape by the use of flexible inorganic zirconia substrates. For this purpose, we applied our developed embedding method to integrate the micro actuators in modern carbon/glass fiber reinforced polymer (CFRP/GFRP) materials. Next, the embedded actuator samples were mounted on a mechanical air profile-like fixture and placed in the icing wind tunnel iCORE. The samples were tested in rime ice conditions at temperatures of -15 to -20° C and air speeds up to 30 m/s. Unlike other groups we used a thin film zirconia substrate as dielectric for the plasma actuator. Due to the low substrate thickness of just 150 µm, an operating voltage of 2 kVRMS is already sufficient enough for a stable plasma formation. The experiments show that the operated actuator was able to prevent the ice formation and first indications of a De-icing function were also found. Hence, we show that it is feasible to realize an anti-icing system with zirconia-based plasma actuators operated at lower voltages compared to conventional ones.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
We present the application of plasma actuators as a technology for ice prevention at airfoils. The miniaturized dielectric barrier discharge (DBD) plasma actuators (PA) were fabricated by means of microelectromechanical systems (MEMS). We elucidate how to make the actuator samples scalable and applicable to any desired shape by the use of flexible inorganic zirconia substrates. For this purpose, we applied our developed embedding method to integrate the micro actuators in modern carbon/glass fiber reinforced polymer (CFRP/GFRP) materials. Next, the embedded actuator samples were mounted on a mechanical air profile-like fixture and placed in the icing wind tunnel iCORE. The samples were tested in rime ice conditions at temperatures of -15 to -20° C and air speeds up to 30 m/s. Unlike other groups we used a thin film zirconia substrate as dielectric for the plasma actuator. Due to the low substrate thickness of just 150 µm, an operating voltage of 2 kVRMS is already sufficient enough for a stable plasma formation. The experiments show that the operated actuator was able to prevent the ice formation and first indications of a De-icing function were also found. Hence, we show that it is feasible to realize an anti-icing system with zirconia-based plasma actuators operated at lower voltages compared to conventional ones. |
2019
|
Lindner, M.; Berndt, D.; Jungbauer, B.; Ehrlich, I.; Schreiner, R.; Pipa, A. V.; Hink, R.; Foest, R.; Brandenburg, R.; Max, A.; Caspari, R. Fabrication, surface integration and testing of miniaturized dielectric barrier discharge plasma actuators for active flow control applications. Leichtbau Konferenzbeitrag In: AIAA Aviation 2019 Forum Dallas, Texas, 2019. @inproceedings{Lindner2019,
title = {Fabrication, surface integration and testing of miniaturized dielectric barrier discharge plasma actuators for active flow control applications.},
author = {M. Lindner and D. Berndt and B. Jungbauer and I. Ehrlich and R. Schreiner and A. V. Pipa and R. Hink and R. Foest and R. Brandenburg and A. Max and R. Caspari},
url = {https://arc.aiaa.org/doi/abs/10.2514/6.2019-2998},
doi = {10.2514/6.2019-2998},
year = {2019},
date = {2019-07-15},
address = {Dallas, Texas},
organization = {AIAA Aviation 2019 Forum},
abstract = {We present the realization and characterization of miniaturized dielectric barrier discharge (DBD) based plasma actuators (PA) by means of microelectromechanical systems (MEMS). Different organic and inorganic dielectric materials and electrode metals have been tested with respect to their resistance against low-temperature plasma. To make the actuator samples scalable and applicable to any desired shape we developed an embedding method to integrate the micro actuator in modern carbon/glass fiber reinforced polymer (CFRP/GFRP) materials to meet the requirements of modern aviation and automotive bodywork. In this context, we further show that the realization of PA can even be carried out on flexible inorganic foils. Additionally, microfabrication mehtods give the possibility of introducing a serrated high voltage electrode with which the plasma formation can be facilitated at the peaks due to a local field enhancement. Measurements of the unduced air flow obtained by a Pitot tube show similar velocities as known from macroscopic actuators. We observed that the ionic wind flow its limited in the case when the actuators are placed too close together. This is attributed to a mututal influence of the electric field configuration resulting in lower total electric field strength.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
We present the realization and characterization of miniaturized dielectric barrier discharge (DBD) based plasma actuators (PA) by means of microelectromechanical systems (MEMS). Different organic and inorganic dielectric materials and electrode metals have been tested with respect to their resistance against low-temperature plasma. To make the actuator samples scalable and applicable to any desired shape we developed an embedding method to integrate the micro actuator in modern carbon/glass fiber reinforced polymer (CFRP/GFRP) materials to meet the requirements of modern aviation and automotive bodywork. In this context, we further show that the realization of PA can even be carried out on flexible inorganic foils. Additionally, microfabrication mehtods give the possibility of introducing a serrated high voltage electrode with which the plasma formation can be facilitated at the peaks due to a local field enhancement. Measurements of the unduced air flow obtained by a Pitot tube show similar velocities as known from macroscopic actuators. We observed that the ionic wind flow its limited in the case when the actuators are placed too close together. This is attributed to a mututal influence of the electric field configuration resulting in lower total electric field strength. |
Afanasev, A. Force-oriented 3D printing of continuous fiber-reinforced plastic structures. Leichtbau Konferenzbeitrag In: Mottok, J.; Reichenberger, M. (Hrsg.): Applied Research Conference 2019 – ARC 2019 , S. 213–218, Ostbayerische Technische Hochschule Regensburg Pro Business Verlag, Berlin, 2019, ISBN: 978-3-96409-182-6. @inproceedings{Afanasev2019,
title = {Force-oriented 3D printing of continuous fiber-reinforced plastic structures.},
author = {A. Afanasev},
editor = {J. Mottok and M. Reichenberger},
isbn = {978-3-96409-182-6},
year = {2019},
date = {2019-07-08},
booktitle = {Applied Research Conference 2019 – ARC 2019 },
pages = {213--218},
publisher = {Pro Business Verlag},
address = {Berlin},
organization = {Ostbayerische Technische Hochschule Regensburg},
abstract = {Due to the low mechanical properties, i. e. strength and stiffness of additively manufactured plastic components their use as load-bearing structures is rarely feasible. The solution for this problem may be the use of reinforced plastic filaments with continous fiber reinforcement. By prior identification of highly stressed areas in the component, the reinforcing fibers can be implemented optimally, thus improving the mechanical properties substantially. For this purpose, it is necessary to analyze the load conditions of the component and use the obtained information for the force-oriented implementation of the reinforcement fiber tracts in the 3D printed component. This paper examines the possibilities of obtaining information from a FE analysis by using the FE software ANSYS WORKBENCH for the force-oriented implementation of reinforcing fibers in a 3D printed component and the possibility of subsequent toolpath generation from the obtained information. For this purpose a FE model with a preferably accurate description of bearing and contact conditions for subsequent usage is created and a topology optimization is performed. The vector principles plot analysis option in ANSYS MECHANICAL provides information of particular importance for force-oriented 3D printing. It provides the relative sizes of the principal quantities as well as their direction. Vector principals provide the directions of the highest normal stresses or elastic strains in reaction to a load condition for previously defined body points. By processing the data with the software MATLAB, the information can be used as a basis for the generation of machine code for the implementation of individual reinforcing fiber tracts in a component.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Due to the low mechanical properties, i. e. strength and stiffness of additively manufactured plastic components their use as load-bearing structures is rarely feasible. The solution for this problem may be the use of reinforced plastic filaments with continous fiber reinforcement. By prior identification of highly stressed areas in the component, the reinforcing fibers can be implemented optimally, thus improving the mechanical properties substantially. For this purpose, it is necessary to analyze the load conditions of the component and use the obtained information for the force-oriented implementation of the reinforcement fiber tracts in the 3D printed component. This paper examines the possibilities of obtaining information from a FE analysis by using the FE software ANSYS WORKBENCH for the force-oriented implementation of reinforcing fibers in a 3D printed component and the possibility of subsequent toolpath generation from the obtained information. For this purpose a FE model with a preferably accurate description of bearing and contact conditions for subsequent usage is created and a topology optimization is performed. The vector principles plot analysis option in ANSYS MECHANICAL provides information of particular importance for force-oriented 3D printing. It provides the relative sizes of the principal quantities as well as their direction. Vector principals provide the directions of the highest normal stresses or elastic strains in reaction to a load condition for previously defined body points. By processing the data with the software MATLAB, the information can be used as a basis for the generation of machine code for the implementation of individual reinforcing fiber tracts in a component. |
