2019
|
Siegl, M.; Ehrlich, I. Internationale Forschung zum Biege- und Deformationsverhalten von faserverstärkten Kunststoffrohren. Leichtbau Forschungsbericht Ostbayerische Hochschule Regensburg VMK Verlag für Marketing & Kommunikation GmbH & Co. KG, Forschungsbericht 2019, 2019, ISBN: 978-3-9818209-6-6. Abstract | BibTeX @techreport{Siegl2019,
title = {Internationale Forschung zum Biege- und Deformationsverhalten von faserverstärkten Kunststoffrohren.},
author = {M. Siegl and I. Ehrlich},
editor = {Ostbayerische Technische Hochschule },
isbn = {978-3-9818209-6-6},
year = {2019},
date = {2019-06-01},
address = {VMK Verlag für Marketing & Kommunikation GmbH & Co. KG},
institution = {Ostbayerische Hochschule Regensburg},
abstract = {Rohre aus faserverstärktem Kunststoff werden unter anderem in der Elektroindustrie und demRohrleitungsbau eingesetzt. Die Gründe dafür sind vielfältig. Speziell Glasfasern bieten nebendem Leichtbaupotential auch sehr gute Isolationseigenschaften. Dabei sind diese Rohre häufigeiner Biegebelastung ausgesetzt, dessen Auswirkungen auf die Struktur sich wegen der komplexenMaterialbeschaffenheit mit gängigen Berechnungsmodellen nicht vollständig beschreiben lassen.Deshalb wird im Rahmen des deutsch-französischen Forschungsprojekts 4-Point-Bending Testsdas Biege- und Deformationsverhalten von faserverstärkten Kunststoffrohren unter Biege -belastung umfassend untersucht.},
type = {Forschungsbericht 2019},
keywords = {},
pubstate = {published},
tppubtype = {techreport}
}
Rohre aus faserverstärktem Kunststoff werden unter anderem in der Elektroindustrie und demRohrleitungsbau eingesetzt. Die Gründe dafür sind vielfältig. Speziell Glasfasern bieten nebendem Leichtbaupotential auch sehr gute Isolationseigenschaften. Dabei sind diese Rohre häufigeiner Biegebelastung ausgesetzt, dessen Auswirkungen auf die Struktur sich wegen der komplexenMaterialbeschaffenheit mit gängigen Berechnungsmodellen nicht vollständig beschreiben lassen.Deshalb wird im Rahmen des deutsch-französischen Forschungsprojekts 4-Point-Bending Testsdas Biege- und Deformationsverhalten von faserverstärkten Kunststoffrohren unter Biege -belastung umfassend untersucht. |
Schimmer, F.; Ladewig, S.; Motsch, N.; Hausmann, J. M.; Ehrlich, I. Comparison of Low-Velocity Impact Damage Behavior of Unidirectional Carbon Fiber-Reinforced Thermoset and Thermoplastic Composites. Leichtbau Artikel Key Engineering Materials, 809 (22), S. 9-14, 2019. Abstract | Links | BibTeX @article{Schimmer2019,
title = {Comparison of Low-Velocity Impact Damage Behavior of Unidirectional Carbon Fiber-Reinforced Thermoset and Thermoplastic Composites.},
author = {F. Schimmer and S. Ladewig and N. Motsch and J. M. Hausmann and I. Ehrlich},
url = {https://www.scientific.net/KEM.809.9},
doi = {https://doi.org/10.4028/www.scientific.net/KEM.809.9},
year = {2019},
date = {2019-06-01},
journal = {Key Engineering Materials},
volume = {809},
number = {22},
pages = {9-14},
abstract = {This paper investigates the damage behavior of thermoset and thermoplastic fiber-reinforced composites. The specimens were subjected to low-velocity impacts (LVI) to produce barely visible impact damages (BVID). To compare the dependency of the matrix system and the laminate lay-up on the impact damage, four test series were set up. Therefore, laminates with an epoxy (EP) and a polyether ether ketone (PEEK) matrix in a quasi-isotropic (QI) [+45/0/-45/90]2s and an orthotropic (OT) fiber lay-up [0/90]4s were manufactured. To eliminate the influence of variant fiber systems, the thermoplastic tape and the thermoset prepreg contain similar carbon fibers (CF). After impact testing with three different impact energies, inner damages were investigated by using ultrasonic analyses. To get a deeper understanding of the interior damage mechanisms, cross sections of the damaged areas were examined via reflected light microscopy. By using these destructive and non-destructive test methods, significant differences in the damage behavior of composites with thermoplastic and thermoset matrix systems were identified for both laminate lay-ups.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
This paper investigates the damage behavior of thermoset and thermoplastic fiber-reinforced composites. The specimens were subjected to low-velocity impacts (LVI) to produce barely visible impact damages (BVID). To compare the dependency of the matrix system and the laminate lay-up on the impact damage, four test series were set up. Therefore, laminates with an epoxy (EP) and a polyether ether ketone (PEEK) matrix in a quasi-isotropic (QI) [+45/0/-45/90]2s and an orthotropic (OT) fiber lay-up [0/90]4s were manufactured. To eliminate the influence of variant fiber systems, the thermoplastic tape and the thermoset prepreg contain similar carbon fibers (CF). After impact testing with three different impact energies, inner damages were investigated by using ultrasonic analyses. To get a deeper understanding of the interior damage mechanisms, cross sections of the damaged areas were examined via reflected light microscopy. By using these destructive and non-destructive test methods, significant differences in the damage behavior of composites with thermoplastic and thermoset matrix systems were identified for both laminate lay-ups. |
Romano, M.; Ehrlich, I.; Gebbeken, N. Parametric characterization of a mesomechanic kinematic in plain and twill weave 2/2 reinforced composites by FE-calculations. Leichtbau Artikel Archives of Materials Science and Engineering (ArchivesMSE), 1-2 (97), S. 20-38, 2019, ISSN: 1897-2764. Abstract | Links | BibTeX @article{Romano2019,
title = {Parametric characterization of a mesomechanic kinematic in plain and twill weave 2/2 reinforced composites by FE-calculations.},
author = {M. Romano and I. Ehrlich and N. Gebbeken},
url = {HTTPS://ARCHIVESMSE.ORG/RESOURCES/HTML/CMS/MAINPAGE
HTTPS://ARCHIVESMSE.ORG/RESOURCES/HTML/ARTICLESLIST?ISSUEID=12181
HTTPS://ARCHIVESMSE.ORG/RESOURCES/HTML/ARTICLE/DETAILS?ID=190365},
doi = {10.5604/01.3001.0013.2869},
issn = {1897-2764},
year = {2019},
date = {2019-05-01},
journal = {Archives of Materials Science and Engineering (ArchivesMSE)},
volume = {1-2},
number = {97},
pages = {20-38},
abstract = {Purpose: A parametric characterization of a mesomechanic kinematic caused by ondulation in fabric reinforced composites is investigated by numerical investigations. Design/methodology/approach: Due to the definition of plain representative sequences of balanced plain-weave and twill-weave 2/2 fabric reinforced single layers based on sines the variable geometric parameters are the amplitude and the length of the ondulation. Findings: The mesomechanic kinematic can be observed in the FE analyses for both kinds of fabric constructions. Research limitations/implications: The FE analyses consider elasticity and contraction due to Poisson effects, respectively, of the model under selected longitudinal strains. Practical implications: The results are evaluated at relevant positions on the centre-line of the ondulated warp-yarn of the plain representative model. A direct and linear coupling in case of the transversal kinematic behaviour, and thereby a corresponding definite reduction of the evaluated longitudinal strains in terms of the difference of the applied and determined longitudinal strains is identified. Originality/value: Both characteristic purely kinematic reactions due to geometric constraints directly depend on the introduced degree of ondulation. This non-dimensional parameter relates amplitude and length of one complete ondulation, and thus represents the intensity of the ondulation of the respective fabric construction.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Purpose: A parametric characterization of a mesomechanic kinematic caused by ondulation in fabric reinforced composites is investigated by numerical investigations. Design/methodology/approach: Due to the definition of plain representative sequences of balanced plain-weave and twill-weave 2/2 fabric reinforced single layers based on sines the variable geometric parameters are the amplitude and the length of the ondulation. Findings: The mesomechanic kinematic can be observed in the FE analyses for both kinds of fabric constructions. Research limitations/implications: The FE analyses consider elasticity and contraction due to Poisson effects, respectively, of the model under selected longitudinal strains. Practical implications: The results are evaluated at relevant positions on the centre-line of the ondulated warp-yarn of the plain representative model. A direct and linear coupling in case of the transversal kinematic behaviour, and thereby a corresponding definite reduction of the evaluated longitudinal strains in terms of the difference of the applied and determined longitudinal strains is identified. Originality/value: Both characteristic purely kinematic reactions due to geometric constraints directly depend on the introduced degree of ondulation. This non-dimensional parameter relates amplitude and length of one complete ondulation, and thus represents the intensity of the ondulation of the respective fabric construction. |
2018
|
Gebhardt, J. Low Velocity Impact of GFRP Laminate – Experimental Observations and Numerical Modelling. Leichtbau Inproceedings 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. Abstract | BibTeX @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. |
Wenzl, C. Comparison of Analytical and Numerical Results for the Deformation of Circular Curved Structures under Pressure Load. Leichtbau Inproceedings Mottok, J; Reichenberger, M; Bogner, W (Hrsg.): Applied Research Conference 2018 – ARC 2018 , S. 150–155, Ostbayerische Technische Hochschule Regensburg Pro Business Verlag, Berlin, 2018, ISBN: 978-3-96409-018-8. Abstract | BibTeX @inproceedings{Wenzl2018,
title = {Comparison of Analytical and Numerical Results for the Deformation of Circular Curved Structures under Pressure Load. },
author = {C. Wenzl},
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 = {150--155},
publisher = {Pro Business Verlag},
address = {Berlin},
organization = {Ostbayerische Technische Hochschule Regensburg},
abstract = {The Ostbayerische Technische Hochschule (OTH Regensburg) conducts studies about the damage process of physical impacts on curved geometries made of fiber reinforced plastics (FRP). These studies are executed to deepen the research in the field of the influence of a structures curvature on the process of a physical impact. Therefore, the damage behaviour and the deformation during an impact are explored. This paper presents an investigation of the deformation-behaviour of circular curved structures under a static pressure load. This simplification from a dynamic to a static problem leads to several analytic solutions. At first, analytic solutions for circular curved structures with isotropic material properties, for example the theorem of Ecsedi and Dluhi for composite arches is going to be considered. Furthermore, the results are verified by a FEM (Finite Element Method) simulation. The simulation is performed with the help of the program ANSYS. This paper provides an overview over several calculation methods for isotropic materials. This information can be used to develop further calculation methods for pressure loaded structures. Especially methods for the calculation of unconstant curved structures have to be improved. },
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
The Ostbayerische Technische Hochschule (OTH Regensburg) conducts studies about the damage process of physical impacts on curved geometries made of fiber reinforced plastics (FRP). These studies are executed to deepen the research in the field of the influence of a structures curvature on the process of a physical impact. Therefore, the damage behaviour and the deformation during an impact are explored. This paper presents an investigation of the deformation-behaviour of circular curved structures under a static pressure load. This simplification from a dynamic to a static problem leads to several analytic solutions. At first, analytic solutions for circular curved structures with isotropic material properties, for example the theorem of Ecsedi and Dluhi for composite arches is going to be considered. Furthermore, the results are verified by a FEM (Finite Element Method) simulation. The simulation is performed with the help of the program ANSYS. This paper provides an overview over several calculation methods for isotropic materials. This information can be used to develop further calculation methods for pressure loaded structures. Especially methods for the calculation of unconstant curved structures have to be improved. |
