2015
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Baumer, A.; Kastenmeier, A.; Ehrlich, I. A Numerical Study of Reinforced Bolted Composite Joints. Leichtbau Proceedings Article In: Mottok, J.; Reichenberger, M.; Scharfenberg, J.; Ziemann, O. (Hrsg.): Applied Research Conference 2015 – ARC 2015, S. 278–282, Ostbayerische Technische Hochschule Regensburg Book-On-Demand Verlag, 2015, ISBN: 978-3863869458. @inproceedings{Baumer2015,
title = {A Numerical Study of Reinforced Bolted Composite Joints.},
author = {A. Baumer and A. Kastenmeier and I. Ehrlich},
editor = {J. Mottok and M. Reichenberger and J. Scharfenberg and O. Ziemann},
isbn = {978-3863869458},
year = {2015},
date = {2015-07-16},
booktitle = {Applied Research Conference 2015 – ARC 2015},
pages = {278--282},
publisher = {Book-On-Demand Verlag},
organization = {Ostbayerische Technische Hochschule Regensburg},
abstract = {The Finite Element Analysis (FEA) is an effective tool to save time and costs in the development phase of engineering disciplines. Thus the dimensioning can easily be tested and adapted with a simulation instead of expensive experiments. Manufacturing and testing of fiber-reinforced plastic components is very extensive because of their specific material properties, in comparison to metal components. This is one of the main reasons why almost each complex structure of composite material is investigated with a Finite Element Analysis. The aim of this applied research project is the analytical and numerical investigation of reinforced bolted joints at structures of carbon fiber-reinforced plastics (CFRP). Bolted joints are a relatively simple technique to join two parts of different materials with each other. However, the bolt hole reduces the bearing cross-section and induces enormous stress concentrations. That is why reinforcing bolted composite joints is necessary. In this project, it is realized with reinforcement inserts which are integrated into the laminate layup. A superior research project is investigating the load application in highly stressed tubular composite structures. Before the reinforced bolted joints are applied at tubular geometries, the reinforcing effect is investigated at plane CFRP-components in this work. Therefore, at first various laminate layups without reinforcement inserts are compared to an unidirectional (UD) laminate. After that, the inserts are integrated into the simulation of UD-laminae and compared to non-reinforced ones. Next step is the integration of reinforced laminae into an entire laminate layup to prove the general reinforcement at the load introduction spot.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
The Finite Element Analysis (FEA) is an effective tool to save time and costs in the development phase of engineering disciplines. Thus the dimensioning can easily be tested and adapted with a simulation instead of expensive experiments. Manufacturing and testing of fiber-reinforced plastic components is very extensive because of their specific material properties, in comparison to metal components. This is one of the main reasons why almost each complex structure of composite material is investigated with a Finite Element Analysis. The aim of this applied research project is the analytical and numerical investigation of reinforced bolted joints at structures of carbon fiber-reinforced plastics (CFRP). Bolted joints are a relatively simple technique to join two parts of different materials with each other. However, the bolt hole reduces the bearing cross-section and induces enormous stress concentrations. That is why reinforcing bolted composite joints is necessary. In this project, it is realized with reinforcement inserts which are integrated into the laminate layup. A superior research project is investigating the load application in highly stressed tubular composite structures. Before the reinforced bolted joints are applied at tubular geometries, the reinforcing effect is investigated at plane CFRP-components in this work. Therefore, at first various laminate layups without reinforcement inserts are compared to an unidirectional (UD) laminate. After that, the inserts are integrated into the simulation of UD-laminae and compared to non-reinforced ones. Next step is the integration of reinforced laminae into an entire laminate layup to prove the general reinforcement at the load introduction spot. |
Niebauer, M.; Schmid, V.; Ehrlich, I. Failure Criteria of Adhesively Bonded Joints: A Review. Leichtbau Proceedings Article In: Mottok, J.; Reichenberger, M.; Scharfenberg, J.; Ziemann, O. (Hrsg.): Applied Research Conference 2015 – ARC 2015, S. 347–351, Ostbayerische Technische Hochschule Regensburg Book-On-Demand Verlag, 2015, ISBN: 978-3863869458. @inproceedings{Niebauer2015,
title = {Failure Criteria of Adhesively Bonded Joints: A Review.},
author = {M. Niebauer and V. Schmid and I. Ehrlich},
editor = {J. Mottok and M. Reichenberger and J. Scharfenberg and O. Ziemann},
isbn = {978-3863869458},
year = {2015},
date = {2015-07-16},
booktitle = {Applied Research Conference 2015 – ARC 2015},
pages = {347--351},
publisher = {Book-On-Demand Verlag},
organization = {Ostbayerische Technische Hochschule Regensburg},
abstract = {Failure criteria and predicting the critical stress state of adhesively bonded joints is one of the fundamental issues and aspects of designing adhesive bonds. Such adhesive bonded joints are used in many different applications and because of the aim to save resources and energy, engineers have to find new ways of design. A part of this can be the lightweight construction, where it is useful to design with light adhesive bonded joints. Because of this engineers have to know about the performance of such connections. This paper provides a literature review on failure criteria and strength prediction on adhesively bonded joints. The review covers articles published from 1973 until 2013 and divides the topic into several categories such as critical elastic stress states, fracture mechanics, adhesive failure due to plasticity and damage mechanics. In addition, relevant design aspects and details are discussed and available approaches, appropriate for analytical and numerical solutions are identified. },
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Failure criteria and predicting the critical stress state of adhesively bonded joints is one of the fundamental issues and aspects of designing adhesive bonds. Such adhesive bonded joints are used in many different applications and because of the aim to save resources and energy, engineers have to find new ways of design. A part of this can be the lightweight construction, where it is useful to design with light adhesive bonded joints. Because of this engineers have to know about the performance of such connections. This paper provides a literature review on failure criteria and strength prediction on adhesively bonded joints. The review covers articles published from 1973 until 2013 and divides the topic into several categories such as critical elastic stress states, fracture mechanics, adhesive failure due to plasticity and damage mechanics. In addition, relevant design aspects and details are discussed and available approaches, appropriate for analytical and numerical solutions are identified. |
Romano, M.; Eisenried, M.; Jungbauer, B.; Ehrlich, I.; Gebbeken, N. Influence of parameters of the production process on the material quality of unidirectionally reinforced prepregs. Leichtbau Artikel In: Journal of Achievements in Materials and Manufacturing Engineering (JAMME), Bd. 68, Nr. 1, S. 32-44, 2015, ISSN: 1734-8412. @article{Romano2015,
title = {Influence of parameters of the production process on the material quality of unidirectionally reinforced prepregs.},
author = {M. Romano and M. Eisenried and B. Jungbauer and I. Ehrlich and N. Gebbeken},
url = {http://jamme.acmsse.h2.pl/vol68_1/6815.pdf},
issn = {1734-8412},
year = {2015},
date = {2015-01-01},
journal = {Journal of Achievements in Materials and Manufacturing Engineering (JAMME)},
volume = {68},
number = {1},
pages = {32-44},
abstract = {The aim of the prepreg production device is to impregnate different types of reinforcement fibers with an arbitrarily selectable thermoset matrix system that completely satisfies the requirements for autoclave processing. As the prepreg production device is designed and built up modularly every module corresponds one step in the process. To identify the parameters of the production process and investigate its sensitivity on the material quality of both the prepreg as an uncured semi-finished product and the composite as the cured material experimental investigations regarding the resin flow, fiber volume content, mass per unit area and void content are carried out. Overall four material combinations have been investigated, where in each case the selected impregnation temperature and the width of the impregnation gap has been reproducibly varied in selected steps. The experimental characterization of the prepregs and of the composite material is carried out according to German standards. Used parameters clearly affect the material properties, so that a proper impregnation and curing process can be achieved by optimizing the parameter to desired values.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The aim of the prepreg production device is to impregnate different types of reinforcement fibers with an arbitrarily selectable thermoset matrix system that completely satisfies the requirements for autoclave processing. As the prepreg production device is designed and built up modularly every module corresponds one step in the process. To identify the parameters of the production process and investigate its sensitivity on the material quality of both the prepreg as an uncured semi-finished product and the composite as the cured material experimental investigations regarding the resin flow, fiber volume content, mass per unit area and void content are carried out. Overall four material combinations have been investigated, where in each case the selected impregnation temperature and the width of the impregnation gap has been reproducibly varied in selected steps. The experimental characterization of the prepregs and of the composite material is carried out according to German standards. Used parameters clearly affect the material properties, so that a proper impregnation and curing process can be achieved by optimizing the parameter to desired values. |
2014
|
Dinnebier, D.; Ehrlich, I. The effects of severe temperature changes and high humidity on porous CFRP. Leichtbau Artikel In: Journal of Achievements in Materials and Manufacturing Engineering (JAMME), Bd. 67, Nr. 1, S. 5–19, 2014. @article{Dinnebier2014,
title = {The effects of severe temperature changes and high humidity on porous CFRP.},
author = {D. Dinnebier and I. Ehrlich},
year = {2014},
date = {2014-11-01},
journal = {Journal of Achievements in Materials and Manufacturing Engineering (JAMME)},
volume = {67},
number = {1},
pages = {5--19},
abstract = {A route to manufacture porous carbon fiber reinforced plastic (CFRP) for study purposes is described. The porous CFRP is characterized using standard techniques such as matrix digestion as well as the more sophisticated method of high resolution Microfocus X-Ray Tomography (μCT). A comparison of the results of those methods is presented. The mass gains of specimens with a wide range of porosity have been measured both in constant humidity and in alternating environments. It could be shown that severe temperature changes can temporarily increase the moisture content of porous CFRP. However, after the return to a constant environment, the moisture content returns back to saturation levels. Furthermore, it could be shown by X-Ray Tomography that even under severe climatic conditions no permanent liquid water condensates inside the pores. Using Microfocus Computed Tomography it could be shown that even after nearly a year under hot-wet conditions and more than 150 severe temperature cycles there is no liquid water detectable inside the pores.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A route to manufacture porous carbon fiber reinforced plastic (CFRP) for study purposes is described. The porous CFRP is characterized using standard techniques such as matrix digestion as well as the more sophisticated method of high resolution Microfocus X-Ray Tomography (μCT). A comparison of the results of those methods is presented. The mass gains of specimens with a wide range of porosity have been measured both in constant humidity and in alternating environments. It could be shown that severe temperature changes can temporarily increase the moisture content of porous CFRP. However, after the return to a constant environment, the moisture content returns back to saturation levels. Furthermore, it could be shown by X-Ray Tomography that even under severe climatic conditions no permanent liquid water condensates inside the pores. Using Microfocus Computed Tomography it could be shown that even after nearly a year under hot-wet conditions and more than 150 severe temperature cycles there is no liquid water detectable inside the pores. |
Dinnebier, D.; Ehrlich, I. The Effects of Severe Temperature Changes and High Humidity on Porous CFRP. Leichtbau Proceedings Article In: Meran, C. (Hrsg.): Proceedings of the 15th International Materials Symposium (IMSP’2014), S. 433–440, Pamukkale University (Denizli, Turkey) 2014. @inproceedings{Dinnebier2014b,
title = {The Effects of Severe Temperature Changes and High Humidity on Porous CFRP.},
author = {D. Dinnebier and I. Ehrlich},
editor = {C. Meran},
year = {2014},
date = {2014-10-01},
booktitle = {Proceedings of the 15th International Materials Symposium (IMSP’2014)},
pages = {433--440},
organization = {Pamukkale University (Denizli, Turkey)},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
|