@inproceedings{43236,
author = {{Rüther, Torben and Schmid, Hans-Joachim}},
keywords = {{CDMA}},
location = {{Paderborn}},
title = {{{CDMA: Centrifugal Differential Mobility Analyzer - Ein Messprinzip zur Bestimmung von Multidimensionalen Partikeleigenschaften (Vortrag)}}},
year = {{2023}},
}
@article{43034,
abstract = {{Abstract
The accessibility to rheological parameters for concrete is becoming more and more relevant. This is mainly related to the constantly emerging challenges, such as not only the development of high-strength concretes is progressing very fast but also the simulation of the flow behaviour is of high importance. The main problem, however, is that the rheological characterisation of fresh concrete is not possible via commercial rheometers. The so-called concrete rheometers provide valuable relative values for comparing different concretes, but they cannot measure absolute values. Therefore, we developed an adaptive coaxial concrete rheometer (ACCR) that allows the measurement of fresh concrete with particles up to
d
max
=
5.5
mm
{d}_{{\rm{\max }}}=5.5\hspace{.5em}{\rm{mm}}
. The comparison of the ACCR with a commercial rheometer showed very good agreement for selected test materials (Newtonian fluid, shear thinning fluid, suspension, and yield stress fluid), so that self-compacting concrete was subsequently measured. Since these measurements showed a very high reproducibility, the rheological properties of the fresh concrete could be determined with high accuracy. The common flow models (Bingham (B), Herschel–Bulkley, modified Bingham (MB) models) were also tested for their applicability, with the Bingham and the modified Bingham model proving to be the best suitable ones.}},
author = {{Josch, Sebastian and Jesinghausen, Steffen and Schmid, Hans-Joachim}},
issn = {{1617-8106}},
journal = {{Applied Rheology}},
keywords = {{Condensed Matter Physics, General Materials Science}},
number = {{1}},
publisher = {{Walter de Gruyter GmbH}},
title = {{{Development of an adaptive coaxial concrete rheometer and rheological characterisation of fresh concrete}}},
doi = {{10.1515/arh-2022-0140}},
volume = {{33}},
year = {{2023}},
}
@article{43128,
author = {{Rüther, Moritz Johannes and Klippstein, Sven Helge and Ponusamy, SathishKumar and Rüther, Torben and Schmid, Hans-Joachim}},
issn = {{0032-5910}},
journal = {{Powder Technology}},
keywords = {{General Chemical Engineering}},
publisher = {{Elsevier BV}},
title = {{{Flowability of polymer powders at elevated temperatures for additive manufacturing}}},
doi = {{10.1016/j.powtec.2023.118460}},
volume = {{422}},
year = {{2023}},
}
@inproceedings{44244,
author = {{Ponusamy, SathishKumar and Schmid, Hans-Joachim}},
location = {{Braunschweig}},
title = {{{Dynamisch-mechanische Polymerpartikelverrundung zur Verbesserung der Fließfähigkeit für das selektive Lasersintern}}},
year = {{2023}},
}
@inproceedings{44103,
author = {{Neukötter, Moritz and Jesinghausen, Steffen and Schmid, Hans-Joachim}},
location = {{Berlin}},
title = {{{Particles as Seeds for Instabilities in Uniaxially Elongated Polymer Suspension Filaments (Presentation)}}},
year = {{2023}},
}
@misc{44101,
author = {{Temborius, Fiona and Neukötter, Moritz}},
title = {{{Polymere unter Dehnung: Untersuchung der Filamententstehung von Polymerblends und deren Instabilitätsentstehung durch Partikeln}}},
year = {{2023}},
}
@misc{42999,
author = {{Bünder, Dirk and Neukötter, Moritz}},
title = {{{Theoretische Beschreibung des Polymerverhaltens in Polymerlösungen und - schmelzen: Simulationen anhand des Rolie-Poly-Modells}}},
year = {{2023}},
}
@article{46815,
abstract = {{In this work, the influence of the filler–matrix adhesion on the tensile properties of laser-sintered parts built with Polyamide 613 filled with glass beads was investigated. For this purpose, dry blends of glass beads with and without organosilane coupling agents and polyamide powder were prepared and processed into tensile specimens on an EOS P396 laser sintering system. The samples were tested both in the dry state and after an accelerated conditioning in a climate chamber. Furthermore, finite element method (FEM) simulations were performed to model the extreme cases of optimum adhesion and no adhesion. By correlating the tensile tests with the simulation results and by analyzing the fracture surfaces, it was shown that the filler–matrix adhesion is sufficient in the dry state but is strongly degraded by conditioning. Even the presence of various organosilane thin films could not prevent a strong deterioration of the filler–matrix adhesion and the associated deterioration of the mechanical properties. Since a comparison with an injection-molded sample of the same polymer filler combination shows identical behavior after conditioning, it is assumed that this problem is not limited to additively manufactured parts.}},
author = {{Kletetzka, Ivo and Kosanke, Maren and Meinderink, Dennis and Neßlinger, Vanessa and Grundmeier, Guido and Schmid, Hans-Joachim}},
issn = {{2363-9512}},
journal = {{Progress in Additive Manufacturing}},
keywords = {{Industrial and Manufacturing Engineering}},
publisher = {{Springer Science and Business Media LLC}},
title = {{{Influence of the filler–matrix adhesion and the effects of conditioning on tensile properties of laser-sintered parts built with polyamide–glass bead dry blends}}},
doi = {{10.1007/s40964-023-00501-z}},
year = {{2023}},
}
@unpublished{43049,
abstract = {{Abstract
In this work, the influence of the filler matrix adhesion on the tensile properties of laser-sintered parts built with Polyamide 613 filled with glass beads was investigated. For this purpose, dry blends of glass beads with and without organosilane coupling agents and polyamide powder were prepared and processed into tensile specimens on an EOS P396. The samples were tested both in the dry state and after an accelerated conditioning in a climate chamber. Furthermore, FEM simulations were performed to model the limiting cases of optimum adhesion and no adhesion. By correlating the tensile tests with the simulation results and by analyzing the fracture surfaces, it was shown that the filler matrix adhesion is sufficient in the dry state but is strongly degraded by conditioning. Even the presence of various organosilane thin films could not prevent a strong deterioration of the filler-matrix adhesion and the associated deterioration of the mechanical properties. Since a comparison with an injection molded sample of the same polymer filler combination shows identical behavior after conditioning, it is assumed that this problem is not limited to additively manufactured parts.}},
author = {{Kletetzka, Ivo and Kosanke, Maren and Meinderink, Dennis and Neßlinger, Vanessa and Grundmeier, Guido and Schmid, Hans-Joachim}},
publisher = {{Research Square Platform LLC}},
title = {{{Influence of the filler matrix adhesion and the effects of conditioning on tensile properties of laser sintered parts built with polyamide glass bead dry blends}}},
year = {{2023}},
}
@inproceedings{45783,
author = {{Kletetzka, Ivo}},
location = {{Berlin}},
title = {{{Tensile Testing for Polymer AM - Best Pratice at the DMRC}}},
year = {{2023}},
}
@article{43046,
abstract = {{In the laser sintering technology, the semi-crystalline polymer material is exposed to elevated temperatures during processing, which leads to serious material ageing for most materials. This has already been investigated intensively by various authors. However, the ageing of the material at ambient temperatures during shelf life has not been the focus so far. The need to analyse the shelf life can be derived from an ecological and economic point of view. This work is focusing on the shelf life of PA2200 (PA12). To reduce the potential influences of powder production fluctuations, two different powder batches stored for 5.5 years and 6.5 years are investigated and compared to a reference powder produced 0.5 years before these investigations. Multiple powder analyses and part characterisations have been performed. A significant yellowing and molecular chain length reduction can be derived from the measurement results. Whereas the influence on mechanical part performance was minor, the parts built with the stored powders are more yellowish. As it is most likely that this is due to the consumption of polyamide stabilisers, it can be assumed that these parts will be subject to significantly faster ageing. Therefore, it is still not recommended to use the stored powders for critical parts or light intense and humid environments.}},
author = {{Klippstein, Sven Helge and Kletetzka, Ivo and Sural, Ilknur and Schmid, Hans-Joachim}},
journal = {{The International Journal of Advanced Manufacturing Technology }},
keywords = {{Selective laser sintering, Shelf life, Polyamide 12, powder, PA2200, material ageing}},
publisher = {{Springer}},
title = {{{Influence of a prolonged shelf time on PA12 laser sintering powder and resulting part properties}}},
doi = {{https://doi.org/10.1007/s00170-023-11243-1}},
year = {{2023}},
}
@misc{46861,
author = {{Sajadi, Said}},
title = {{{Charakterisierung und Bewertung von flammgeschützten PA12 Pulvermischungen hinsichtlich der Verarbeitbarkeit im Lasersinter-Prozess}}},
year = {{2023}},
}
@inbook{46870,
author = {{Menge, Dennis and Milaege, Dennis and Hoyer, Kay-Peter and Schmid, Hans-Joachim and Schaper, Mirko}},
booktitle = {{Climate Protection, Resource Efficiency, and Sustainable Engineering}},
editor = {{Horwath, Illona and Schweizer, Swetlana}},
isbn = {{9783837663778}},
issn = {{2703-1543}},
publisher = {{transcript Verlag}},
title = {{{Case Study IV: Individualized Medical Technology using Additive Manufacturing}}},
doi = {{10.14361/9783839463772-007}},
year = {{2023}},
}
@misc{42997,
author = {{Almohammad, Ahmad and Neukötter, Moritz}},
title = {{{Untersuchung dehnrheologischer Eigenschaften - Suspensionen auf Basis von Polymerlösungen }}},
year = {{2023}},
}
@misc{56951,
author = {{Otto, Moritz and Neukötter, Moritz}},
title = {{{Konstruktion einer Vorrichtung zur Probenherstellung für das Sermanat-Dehnrheometer}}},
year = {{2023}},
}
@misc{56953,
author = {{Gunasagran, Sharin Kumar and Neukötter, Moritz}},
title = {{{Automatisierung der Auswertungen rheologischer Messungen (Studienarbeit)}}},
year = {{2023}},
}
@misc{42995,
author = {{Al Mamoun, Mohamed and Neukötter, Moritz}},
title = {{{Evaluation of self-built low-budget particle sensors (Study Project)}}},
year = {{2023}},
}
@inproceedings{44102,
author = {{Neukötter, Moritz and Jesinghausen, Steffen and Schmid, Hans-Joachim}},
location = {{Athens}},
title = {{{Instabilities of Polymer Melt Suspensions under Uniaxial Extension (Poster)}}},
year = {{2023}},
}
@article{54632,
author = {{Bentrup, Leon Alexander and Gräßer, Melanie and Temmen, Katrin and Schmid, Hans-Joachim}},
journal = {{die hochschullehre}},
number = {{9}},
publisher = {{wbv Publikation}},
title = {{{Entwicklung eines neuen Konzeptes zur Vermittlung von Lerntechniken und Selbstlernkompetenzen für Studierende des Maschinenbaus an der Universität Paderborn}}},
doi = {{10.3278/HSL2310W}},
year = {{2023}},
}
@inproceedings{51727,
author = {{Beimdiek, Janis and Schmid, Hans-Joachim}},
location = {{Nürnberg}},
publisher = {{VDI Verlag}},
title = {{{Entrained flow SCR using an in-situ synthesis of catalyst particles for a combined flue gas cleaning system}}},
year = {{2023}},
}