2018
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Gebhardt, J. Low Velocity Impact of GFRP Laminate – Experimental Observations and Numerical Modelling. Leichtbau Proceedings Article In: Mottok, J.; Reichenberger, M.; Bogner, W. (Hrsg.): Applied Research Conference 2018 – ARC 2018, S. 211–215, Ostbayerische Technische Hochschule Regensburg Pro Business Verlag, Berlin, 2018, ISBN: 978-3-96409-018-8. @inproceedings{Gebhardt2018,
title = {Low Velocity Impact of GFRP Laminate – Experimental Observations and Numerical Modelling.},
author = {J. Gebhardt},
editor = {J. Mottok and M. Reichenberger and W. Bogner},
isbn = {978-3-96409-018-8},
year = {2018},
date = {2018-07-10},
booktitle = {Applied Research Conference 2018 – ARC 2018},
pages = {211--215},
publisher = {Pro Business Verlag},
address = {Berlin},
organization = {Ostbayerische Technische Hochschule Regensburg},
abstract = {Within the framework of the development of a Structural Health Monitoring System (SHM) for composite aircraft structures subjected to impact hazards like bird strikes and swirled up small parts during take-off and landing, lab scaled tests are conducted to achieve a fundamental understanding of composite damage mechanisms. An experimental and numerical investigation of low-velocity impacts of composite plates is conducted. By comparing the quasi-continous measuring signal and post-impact damage areas to numerical analysis results, the simulation can be adapted to the experiment by a numerical calibration. A drop tower test device for low-velocity impact testing, according to DIN EN 6038 was instrumented with a force transducer to determine the time-dependent contact force between the impactor and and specimen following ASTM D3763. In each test case, two plates are tested with 9, 12 and 16 joules impact energy, and the transient force characteristics as well as the damage surfaces are evaluated. The investigated impact scenarios last typically 6 ms with multiple load drops and superposed oscillations. Through the high-resolution measurement of the contact force it seems to be possible to use a spectograph to identify the delamination threshold load. The formation of the damage area was simulated in a numerical model utilizing LS-DYNA which shows good agreement with the experiment. },
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Within the framework of the development of a Structural Health Monitoring System (SHM) for composite aircraft structures subjected to impact hazards like bird strikes and swirled up small parts during take-off and landing, lab scaled tests are conducted to achieve a fundamental understanding of composite damage mechanisms. An experimental and numerical investigation of low-velocity impacts of composite plates is conducted. By comparing the quasi-continous measuring signal and post-impact damage areas to numerical analysis results, the simulation can be adapted to the experiment by a numerical calibration. A drop tower test device for low-velocity impact testing, according to DIN EN 6038 was instrumented with a force transducer to determine the time-dependent contact force between the impactor and and specimen following ASTM D3763. In each test case, two plates are tested with 9, 12 and 16 joules impact energy, and the transient force characteristics as well as the damage surfaces are evaluated. The investigated impact scenarios last typically 6 ms with multiple load drops and superposed oscillations. Through the high-resolution measurement of the contact force it seems to be possible to use a spectograph to identify the delamination threshold load. The formation of the damage area was simulated in a numerical model utilizing LS-DYNA which shows good agreement with the experiment. |
Siegl, M.; Ehrlich, I. Einfluss von Prozessparametern auf die Schmelzimprägnierung zur Herstellung von faserverstärkten Thermoplasten. Leichtbau Forschungsbericht Ostbayerische Technische Hochschule Regensburg VMK Verlag für Marketing & Kommunikation GmbH & Co. KG, 2018, ISBN: 978-3-9818209-4-2. @techreport{Siegl2018b,
title = {Einfluss von Prozessparametern auf die Schmelzimprägnierung zur Herstellung von faserverstärkten Thermoplasten.},
author = {M. Siegl and I. Ehrlich},
editor = {Ostbayerische Technische Hochschule},
isbn = {978-3-9818209-4-2},
year = {2018},
date = {2018-06-01},
address = {VMK Verlag für Marketing & Kommunikation GmbH & Co. KG},
institution = {Ostbayerische Technische Hochschule Regensburg},
abstract = {Die Erforschung von faserverstärkten Kunststoffen (FVK) mit thermoplastischer Matrix ist aufgrund der Schweißeignung als Verbindungstechnologie, der thermischen Umformbarkeit, der Recyclebarkeit sowie der verkürzten Prozesszeiten im Vergleich zu den vorwiegend eingesetzten faserverstärkten Duroplasten erstrebenswert. Die Wechselwirkung zwischen den physikalischen, mechanischen und geometrischen Parametern erhöht den Komplexitätsgrad des Herstellungsprozesses. Ziel ist daher die Entwicklung einer Imprägniertechnik, die eine Fasertränkung mittels eines Thermoplastschmelzbades ermöglicht.},
keywords = {},
pubstate = {published},
tppubtype = {techreport}
}
Die Erforschung von faserverstärkten Kunststoffen (FVK) mit thermoplastischer Matrix ist aufgrund der Schweißeignung als Verbindungstechnologie, der thermischen Umformbarkeit, der Recyclebarkeit sowie der verkürzten Prozesszeiten im Vergleich zu den vorwiegend eingesetzten faserverstärkten Duroplasten erstrebenswert. Die Wechselwirkung zwischen den physikalischen, mechanischen und geometrischen Parametern erhöht den Komplexitätsgrad des Herstellungsprozesses. Ziel ist daher die Entwicklung einer Imprägniertechnik, die eine Fasertränkung mittels eines Thermoplastschmelzbades ermöglicht. |
Pongratz, C.; Ehrlich, I. High-End-Strukturen für den Leichtbau – mit faserverstärktem 3D-Druck Leichtbau Forschungsbericht Ostbayerische Hochschule Regensburg VMK Verlag für Marketing & Kommunikation GmbH & Co. KG, Forschungsbericht 2018, 2018, ISBN: 978-3-9818209-4-2. @techreport{Pongratz2018,
title = {High-End-Strukturen für den Leichtbau – mit faserverstärktem 3D-Druck},
author = {C. Pongratz and I. Ehrlich},
editor = {Ostbayerische Technische Hochschule},
isbn = {978-3-9818209-4-2},
year = {2018},
date = {2018-06-01},
address = {VMK Verlag für Marketing & Kommunikation GmbH & Co. KG},
institution = {Ostbayerische Hochschule Regensburg},
abstract = {Additive Fertigung, oder auch 3D-Druck, erlaubt die Herstellung von komplexen Bauteilen mitnahezu beliebiger Geometrie. Werden dabei Kunststoffe genutzt, sind die mechanischen Eigen-schaften des erzeugten Bauteils jedoch begrenzt und oft nur für Prototyping-Anwendungengeeignet. Ziel des Projekts FIBER-PRINT ist die Entwicklung bzw. Weiterentwicklung eines additi-ven Fertigungsprozesses mit Faserverstärkung. Durch die Einbringung und kraftflussgerechteAnordnung von Endlosfasern kann die mechanische Belastbarkeit signifikant gesteigert werdenund dadurch können auch lasttragende Strukturen additiv gefertigt werden.},
type = {Forschungsbericht 2018},
keywords = {},
pubstate = {published},
tppubtype = {techreport}
}
Additive Fertigung, oder auch 3D-Druck, erlaubt die Herstellung von komplexen Bauteilen mitnahezu beliebiger Geometrie. Werden dabei Kunststoffe genutzt, sind die mechanischen Eigen-schaften des erzeugten Bauteils jedoch begrenzt und oft nur für Prototyping-Anwendungengeeignet. Ziel des Projekts FIBER-PRINT ist die Entwicklung bzw. Weiterentwicklung eines additi-ven Fertigungsprozesses mit Faserverstärkung. Durch die Einbringung und kraftflussgerechteAnordnung von Endlosfasern kann die mechanische Belastbarkeit signifikant gesteigert werdenund dadurch können auch lasttragende Strukturen additiv gefertigt werden. |
Siegl, M.; Rieger, D.; Kovárík, T.; Ehrlich, I. Long-Term Behavior of Thermoplastics under UV Light tested by a self-build Device Leichtbau Proceedings Article In: OTH Regensburg, OTH Amberg-Weiden (Hrsg.): Proceedings of the 3rd OTH-Clusterkonferenz, S. 118–122, Regensburg, Germany, 2018, ISBN: 978-3-9818209-4-2. @inproceedings{Siegl2018,
title = {Long-Term Behavior of Thermoplastics under UV Light tested by a self-build Device},
author = {M. Siegl and D. Rieger and T. Kovárík and I. Ehrlich},
editor = {OTH Regensburg, OTH Amberg-Weiden},
url = {https://www.oth-regensburg.de/fileadmin/media/forschung/Dateien_2018/Clusterkonferenz-Tagungsband-2018.pdf},
isbn = {978-3-9818209-4-2},
year = {2018},
date = {2018-03-01},
booktitle = {Proceedings of the 3rd OTH-Clusterkonferenz},
pages = {118--122},
address = {Regensburg, Germany},
series = {Schriftenreihe der OTH Regensburg und der OTH Amberg-Weiden},
abstract = {This article presents first results of artificial aging experiments by ultraviolet (UV) irradiation on thermoplastic materials conducted as an intent of the research project Thermoplastic Composite Structures (TheCoS) in collaboration of the Ostbayerische Technische Hochschule (OTH) Regensburg and the University of West Bohemia (UWB) in Pilsen as part of a cross-border cooperation. In technical applications, thermoplastic materials are often affected by aging and a related deterioration of the mechanical properties. Therefore, it is necessary to identify the aging behavior of thermoplastic materials. For this, experiments were performed for three thermoplastic materials, namely polypropylene (PP), ultra high molecular weight polyethylene (UHMWPE) and high impact strength polystyrene (HIPS). For these experiments, a UV chamber was constructed according to the international standard EN ISO 4892-3 for simulation of exposure behind window glass. The results are evaluated by testing the flexural strength and the dynamic mechanical response after a selected period of time under UV light and then compared to untreated test specimens.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
This article presents first results of artificial aging experiments by ultraviolet (UV) irradiation on thermoplastic materials conducted as an intent of the research project Thermoplastic Composite Structures (TheCoS) in collaboration of the Ostbayerische Technische Hochschule (OTH) Regensburg and the University of West Bohemia (UWB) in Pilsen as part of a cross-border cooperation. In technical applications, thermoplastic materials are often affected by aging and a related deterioration of the mechanical properties. Therefore, it is necessary to identify the aging behavior of thermoplastic materials. For this, experiments were performed for three thermoplastic materials, namely polypropylene (PP), ultra high molecular weight polyethylene (UHMWPE) and high impact strength polystyrene (HIPS). For these experiments, a UV chamber was constructed according to the international standard EN ISO 4892-3 for simulation of exposure behind window glass. The results are evaluated by testing the flexural strength and the dynamic mechanical response after a selected period of time under UV light and then compared to untreated test specimens. |
Bohmann, T.; Schlamp, M.; Ehrlich, I. Acoustic emission of material damages in glass fibre-reinforced plastics Leichtbau Artikel In: Composites Part B: Engineering, Bd. 155, S. 444 - 451, 2018, ISSN: 1359-8368. @article{Bohmann2018,
title = {Acoustic emission of material damages in glass fibre-reinforced plastics},
author = {T. Bohmann and M. Schlamp and I. Ehrlich},
doi = {10.1016/j.compositesb.2018.09.018},
issn = {1359-8368},
year = {2018},
date = {2018-01-01},
journal = {Composites Part B: Engineering},
volume = {155},
pages = {444 - 451},
abstract = {The aim of this study is to compare two different standardized testing procedures, tensile testing and Mode-I double cantilever beam (DCB) testing, to evaluate a possible correlation between the dominant failure in glass fibre-reinforced plastics and their according acoustic emissions (AE). AE is processed by using a burst collection of all recorded transient signals and is further analysed with the k-means clustering algorithm. To generate damage related AE, a series of experiments for tensile testing and Mode-I DCB testing is performed on 16-layer glass fibre/epoxy specimens with a cross-ply lay-up for tensile and an unidirectional lay-up for Mode-I DCB testing. Three sensors at tensile testing and one sensor at Mode-I DCB testing gather AE data. The results of clustered burst signals show a good accordance between both testing procedures, with a similar weighted peak frequency (WPF) range in each classified cluster. In total, three different clusters are determined. An assignment of these three clusters to the three dominant damage mechanisms, visually observed by microscopy, is suggested.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The aim of this study is to compare two different standardized testing procedures, tensile testing and Mode-I double cantilever beam (DCB) testing, to evaluate a possible correlation between the dominant failure in glass fibre-reinforced plastics and their according acoustic emissions (AE). AE is processed by using a burst collection of all recorded transient signals and is further analysed with the k-means clustering algorithm. To generate damage related AE, a series of experiments for tensile testing and Mode-I DCB testing is performed on 16-layer glass fibre/epoxy specimens with a cross-ply lay-up for tensile and an unidirectional lay-up for Mode-I DCB testing. Three sensors at tensile testing and one sensor at Mode-I DCB testing gather AE data. The results of clustered burst signals show a good accordance between both testing procedures, with a similar weighted peak frequency (WPF) range in each classified cluster. In total, three different clusters are determined. An assignment of these three clusters to the three dominant damage mechanisms, visually observed by microscopy, is suggested. |