@article{56961,
abstract = {{Der Beitrag untersucht die Effekte eines zwei Sitzungen umfassenden, partizipativen und themenunabhängig integrierbaren Lehrmoduls zur Stärkung der Demokratiebildungskompetenz von Lehramtsstudierenden (N = 159) in einer quasi-experimentellen Studie vom Sommersemester 2023 bis zum Sommersemester 2024. Die Ergebnisse der zweifaktoriellen Varianzanalysen mit Messwiederholungen (Pre-, Post- und Follow-up) verdeutlichen Effekte des Lehrmoduls auf die Selbstwirksamkeitserwartungen der Studierenden zur partizipativ-verfahrensorientierten Unterrichtsgestaltung und auf das methodische Wissen zur demokratischen Erarbeitung von Beurteilungskriterien in unterrichtlichen Lehr-Lern-Arrangements.}},
author = {{Wehde, Janis}},
issn = {{2219-6994}},
journal = {{Zeitschrift für Hochschulentwicklung}},
number = {{3}},
pages = {{267--287}},
publisher = {{OAPublishing Collective}},
title = {{{Effekte eines partizipativen Lehrmoduls zur Demokratiebildung im Lehramtsstudium}}},
doi = {{10.21240/zfhe/19-03/15}},
volume = {{19}},
year = {{2024}},
}
@inproceedings{58503,
author = {{Hambach, Dennis}},
location = {{Paderborn}},
title = {{{Technologieakzeptanz beim Einsatz von Handhelds zur Unterstützung des Hörverstehens. Eine Datendiskussion}}},
year = {{2024}},
}
@inproceedings{49430,
abstract = {{Within the current energy and environmental crisis, new material- and energy-saving processes are needed. For this reason, this study focuses on the development of a new forming technology for Ti-6Al-4V sheet metal. It is based on combination of solution treatment by resistive heating with rapid tool-based quenching and subsequent annealing. This new “TISTRAQ” process is comparable with press-hardening already known for steels and hot die quenching known for aluminium alloys. One of the main influencing factors for this process is the heat transfer coefficient (HTC). It is an important driver for adjustment of basic parameters, as selection of tool material or the forming speed but also plays an important role while elaborating temperature distribution in the numerical model. Therefore, a new and unique test rig was developed to determine the HTC and to perform tool-based heat treatment at specimen level under laboratory conditions. The test rig was used to investigate the influence of the titanium-tool-lubricant system on HTC and cooling rate. Further the effect of heat treatment in the test rig and tool-based quenching on microstructure and mechanical properties was studied. To improve the prediction of the temperature distribution of the titanium during cooling, the HTC was integrated into the numerical process simulation}},
author = {{Kaiser, Maximilian Alexander and Höschen, Fabian and Pfeffer, Nina and Merten, Mathias and Meyer, Thomas and Marten, Thorsten and Rockicki, Pawel and Höppel, Heinz Werner and Tröster, Thomas}},
booktitle = {{IOM3. Chapter 14: Forming, Machining & Joining [version 1; not peer reviewed]}},
keywords = {{Interfacial heat transfer coefficient, Ti-6Al-4V, nonisothermal forming, thermomechanical processing, TISTRAQ process}},
location = {{Edinburgh}},
title = {{{The new TISTRAQ process: Solution treatment with rapid quenching and annealing for Ti-6Al-4V sheet metal part forming - investigation on heat transfer coefficient and influence on cooling rates}}},
doi = {{doi.org/10.7490/f1000research.1119929.1}},
year = {{2024}},
}
@inproceedings{49437,
abstract = {{The phase and TTT diagrams of the Ti-6Al-4V system allow the development of a new forming process for a more energy- and materialefficient production of sheet metal parts. This new “TISTRAQ” process is composed of two steps. In terms of process technology, the first step is comparable to a direct press-hardening process already well known for steels. In this step, the Ti-6Al-4V sheet material is resistively heated to a temperature below β-transus Tβ and, after a very short holding time, simultaneously formed and quenched by use of water cooled tools. Thereby, the β phase undergoes a martensitic transformation. The second step is a subsequent short-time annealing, which leads to a hardening of the material. In this work, a new test rig using resistive heating technique was used in order to produce
different solution treated and tool quenched (STQ) and subsequently annealed (STA) states. In this paper, the effects of heating rate, solution treatment temperature and holding time on microstructure and mechanical properties are addressed. For the characterisation, tensile testing and scanning electron microscopy were used. By the systematic variation of applied processing parameters, dominating effects on microstructure and mechanical properties were evaluated. For example, the solution treatment temperature was found to have a significant effect on microstructural features and characteristic strength and strain values. The obtained results reveal a high potential for future technical applications.}},
author = {{Pfeffer, Nina and Kaiser, Maximilian Alexander and Meyer, Thomas and Göken, Mathias and Höppel, Heinz Werner}},
booktitle = {{IOM3. Chapter 14: Forming, Machining & Joining [version 1; not peer reviewed]}},
keywords = {{Ti-6Al-4V, thermomechanical processing, resistive heating, quench-forming, process parameter-microstructure-properties relationship}},
location = {{Edinburgh}},
title = {{{The new TISTRAQ process: Solution treatment with rapid quenching and annealing for Ti-6Al-4V sheet metal part forming - the effect of processing parameters on microstructure and mechanical properties}}},
doi = {{https://doi.org/10.7490/f1000research.1119929.1}},
year = {{2024}},
}
@article{60106,
abstract = {{ Clinching is a mechanical joining technology, in which a mainly form-fit joint is created by means of local cold forming. To characterize the load-bearing behavior of such joints, they are typically analyzed destructively, for example by tensile-shear tests in combination with metallographic sections. However, both the initiation and progress of failure can only be described to a limited extent by this method. Furthermore, these tests allow only limited conclusions about clinch points under in-service loading. More purposefully, clinch points can be analyzed nondestructively by combining in-situ computed tomography (CT) and transient dynamic analysis (TDA). The TDA continuously measures the dynamic behavior of the specimen and indicates failure events like crack initiation, which then can be evaluated thoroughly by stopping the test and performing a CT scan. To qualify the TDA for this task, it is necessary to link the observed damage behavior with specific dynamic characteristics. In this work, the complementation of in-situ CT and TDA is investigated by testing a clinched single-lap tensile-shear specimen made of aluminum. The testing procedure is stepwise: at certain displacement levels, the specimen is investigated by in-situ CT and TDA. While the in-situ CT provides the location, extent, and development of the failure phenomena, the TDA uses this information to evaluate the dynamic signal and detect relevant frequency ranges, which indicate damage events. The results demonstrate, that failure initiation and progression can be analyzed efficiently by combining both measuring systems. The TDA reliably detects relevant signal changes in the monitored frequency band. By means of in-situ computed tomography, the corresponding failure phenomena can be described in detail, enhancing the understanding of the load-bearing and deformation behavior of clinch points. The concatenation of characteristic signal changes and observed failure phenomena can henceforth be transferred to analyze complex structures during operation nondestructively by TDA. }},
author = {{Reschke, G and Köhler, D and Kupfer, R and Troschitz, J and Gude, M and Brosius, A}},
issn = {{0954-4089}},
journal = {{Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering}},
publisher = {{SAGE Publications}},
title = {{{In-situ computed tomography and transient dynamic analysis – failure analysis of a single-lap tensile-shear test with clinch points}}},
doi = {{10.1177/09544089241251646}},
year = {{2024}},
}
@article{60105,
abstract = {{ Lightweight design by using low-density and load-adapted materials can reduce the weight of vehicles and the emissions generated during operation. However, the usage of different materials requires innovative joining technologies with increased versatility. In this investigation, the focus is on describing and characterising the failure behaviour of connections manufactured by an innovative thermomechanical joining process with adaptable auxiliary joining elements in single-lap tensile-shear tests. In order to analyse the failure development in detail, the specimens are investigated using in-situ computed tomography (in-situ CT). Here, the tensile-shear test is interrupted at points of interest and CT scans are conducted under load. In addition, the interrupted in-situ testing procedure is validated by comparing the loading behaviour with conventional continuous tensile-shear tests. The results of the in-situ investigations of joints with varying material combinations clearly describe the cause of failure, allowing conclusions towards an improved joint design. }},
author = {{Borgert, T and Köhler, D and Wiens, E. and Kupfer, R and Troschitz, J and Homberg, W and Gude, M}},
issn = {{1464-4207}},
journal = {{Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications}},
number = {{12}},
pages = {{2299--2306}},
publisher = {{SAGE Publications}},
title = {{{In-situ computed tomography analysis of the failure mechanisms of thermomechanically manufactured joints with auxiliary joining element}}},
doi = {{10.1177/14644207241232233}},
volume = {{238}},
year = {{2024}},
}
@inproceedings{60107,
abstract = {{Abstract. In lightweight constructions, clinching represents a cost-effective solution, in which joints are produced by local cold forming of the joining parts. Clinching phenomena are typically evaluated using destructive testing methods. While these methods influence the clinch point’s state, in-situ computed tomography (in-situ CT) is able to explore the clinching process with a specimen under load. Here, the path-controlled clinching process is interrupted at certain displacement levels and the specimen is scanned by CT while remaining in a stationary state. These interruptions are always accompanied by settling effects reducing the reaction force. Therefore, in this work, the influence of these interruptions on the force-displacement behavior during clinching and on the final clinch point’s geometric properties is investigated. }},
author = {{Köhler, D. and Kupfer, R. and Troschitz, J. and Gude, M.}},
booktitle = {{Materials Research Proceedings}},
issn = {{2474-395X}},
publisher = {{Materials Research Forum LLC}},
title = {{{In-situ CT of the clinching process – Influence of settling effects due to process interruptions}}},
doi = {{10.21741/9781644903131-187}},
volume = {{41}},
year = {{2024}},
}
@misc{63714,
author = {{Schultz, Andreas Maximilian and Mozgova, Iryna}},
title = {{{Wissensmanagement in Feuerwehren skalierbare IT-Architektur für Erweiterung und Austausch}}},
year = {{2024}},
}
@inproceedings{58233,
abstract = {{Extreme weather situations increasingly lead to hazardous situations with high demands on de-cision-making and communication. Weather and impact forecasts serve to prepare for such an emergency situation, and extreme data must be processed during operations. Therefore, extreme data is categorised with reference to global weather data and data from local situation reconnais-sance using sensors carried by mobile robots. A concept is presented in which information quality is explicitly considered in visualization for situational awareness. This extends existing principles of information visualisation with regard to the uncertainty resulting from extreme data. The re-sults are intended to help decision-makers at different management levels to make informed decisions.}},
author = {{Gräßler, Iris and Pottebaum, Jens and Hieb, Michael and Pratzler-Wanczura, Sylvia and Krüger, Oliver and Kruijff, Ivana and Rupp, Nicola}},
booktitle = {{Proceedings of the Days of Security Research 2023}},
editor = {{Bernsdorf, Bodo}},
location = {{Dortmund}},
publisher = {{Technische Hochschule Georg Agricola}},
title = {{{Weather-induced emergency situations: Extreme data in situational awareness and visualisation}}},
year = {{2024}},
}
@inproceedings{52537,
author = {{Gröger, Benjamin and Wiebicke, Felix and Koch, Ilja and Gude, Maik and Gilich, Julian and Meschut, Gerson}},
booktitle = {{24. Kolloquium: Gemeinsame Forschung in der Klebtechnik}},
location = {{Köln}},
title = {{{Experimentelle und numerische Analyse des Fließverhaltens von hochviskosen Wärmeleitstoffen im Fertigungsprozess}}},
year = {{2024}},
}
@article{63842,
author = {{Hoener, Martin and Bierkandt, Thomas and Shaqiri, Shkelqim and Kasper, Tina}},
issn = {{1540-7489}},
journal = {{Proceedings of the Combustion Institute}},
number = {{1-4}},
publisher = {{Elsevier BV}},
title = {{{N2O oxidized combustion of ethylene: Detailed laminar flame structure and the significance of oxidizer decomposition kinetics for modeling}}},
doi = {{10.1016/j.proci.2024.105683}},
volume = {{40}},
year = {{2024}},
}
@inproceedings{56655,
author = {{Müller, Laura and Schultz, Andreas Maximilian and Altun, Osman and Uhe, Johanna and Koepler, Oliver and Auer, Soeren and Mozgova, Iryna}},
booktitle = {{Proceedings of NordDesign 2024}},
pages = {{514--520}},
publisher = {{The Design Society}},
title = {{{Requirements Analysis of a Research Data Management System in Collaborative Projects}}},
doi = {{10.35199/norddesign2024.55}},
year = {{2024}},
}
@article{57467,
abstract = {{Additive manufacturing of metallic components often results in the formation of columnar grain structures aligned along the build direction. These elongated grains can introduce anisotropy, negatively impacting the mechanical properties of the components. This study aimed to achieve controlled solidification with a fine-grained microstructure to enhance the mechanical performance of printed parts. Stainless steel 316L was used as the test material. High-intensity ultrasound was applied during the direct energy deposition (DED) process to inhibit the formation of columnar grains. The investigation emphasized the importance of amplitude changes of the ultrasound wave as the system’s geometry continuously evolves with the addition of multiple layers and assessed how these changes influence the grain size and distribution. Initial tests revealed significant amplitude fluctuations during layer deposition, highlighting the impact of layer deposition on process uniformity. The mechanical results demonstrated that the application of ultrasound effectively refined the grain structure, leading to a 15% increase in tensile strength compared to conventionally additively manufactured samples.}},
author = {{Lehnert, Dennis and Bödger, Christian and Pabel, Philipp and Scheidemann, Claus and Hemsel, Tobias and Gnaase, Stefan and Kostka, David and Tröster, Thomas}},
issn = {{2073-4352}},
journal = {{Crystals}},
number = {{11}},
publisher = {{MDPI AG}},
title = {{{The Influence of Ultrasonic Irradiation of a 316L Weld Pool Produced by DED on the Mechanical Properties of the Produced Component}}},
doi = {{10.3390/cryst14111001}},
volume = {{14}},
year = {{2024}},
}
@inproceedings{52211,
author = {{Beule, Felix and Teutenberg, Dominik and Meschut, Gerson}},
booktitle = {{DECHEMA-Workshop für Klebstoffanwender: Simulation von Klebverbindungen}},
location = {{Köln}},
title = {{{Klebstoffmodell - Parameteridentifikation, Verifikation und Validierung für den Lastfall Crash}}},
year = {{2024}},
}
@inproceedings{52214,
author = {{Beule, Felix and Teutenberg, Dominik and Meschut, Gerson and Schmelzle, Lars and Possart, Gunnar and Mergheim, Julia and Steinmann, Paul}},
location = {{Köln}},
title = {{{Methodenentwicklung zur Simulation von hyperelastischen Klebverbindungen unter Crashbelastung}}},
year = {{2024}},
}
@book{58800,
author = {{Yang, Keke and Seitz, Georg and Schreiber, Vincent and Meschut, Gerson and Biegler, Max and Jüttner, Sven and Rethmeier, Michael }},
isbn = {{978-3-96780-190-3}},
title = {{{Validierung von Methoden zur Vermeidung von Liquid Metal Embrittlement an realitätsnahen Prinzipbauteilen}}},
year = {{2024}},
}
@inproceedings{62052,
author = {{Reckmann, Eileen and Blomberg, Tobias and Temmen, Katrin}},
location = {{München}},
title = {{{„Das ist genau das richtige Setting“ ‒ Zusammen lehren und lernen im MINT-Cluster MINT4.OWL}}},
year = {{2024}},
}
@inproceedings{62078,
abstract = {{Fiber reinforced plastics (FRP) exhibit strongly non-linear deformation behavior. To capture this in simulations, intricate models with a variety of parameters are typically used. The identification of values for such parameters is highly challenging and requires in depth understanding of the model itself. Machine learning (ML) is a promising approach for alleviating this challenge by directly predicting parameters based on experimental results. So far, this works mostly for purely artificial data. In this work, two approaches to generalize to experimental data are investigated: a sequential approach, leveraging understanding of the constitutive model and a direct, purely data driven approach. This is exemplary carried out for a highly non-linear strain rate dependent constitutive model for the shear behavior of FRP.The sequential model is found to work better on both artificial and experimental data. It is capable of extracting well suited parameters from the artificial data under realistic conditions. For the experimental data, the model performance depends on the composition of the experimental curves, varying between excellently suiting and reasonable predictions. Taking the expert knowledge into account for ML-model training led to far better results than the purely data driven approach. Robustifying the model predictions on experimental data promises further improvement. }},
author = {{Gerritzen, Johannes and Hornig, Andreas and Winkler, Peter and Gude, Maik}},
booktitle = {{ECCM21 - Proceedings of the 21st European Conference on Composite Materials}},
isbn = {{978-2-912985-01-9}},
keywords = {{Direct parameter identification, Machine learning, Convolutional neural networks, Strain rate dependency, Fiber reinforced plastics, woven composites, segmentation, synthetic training data, x-ray computed tomography}},
pages = {{1252–1259}},
publisher = {{European Society for Composite Materials (ESCM)}},
title = {{{Direct parameter identification for highly nonlinear strain rate dependent constitutive models using machine learning}}},
doi = {{10.60691/yj56-np80}},
volume = {{3}},
year = {{2024}},
}
@article{51116,
abstract = {{Self-piercing riveting is an established joining technique for lightweight materials. To increase the sustainability of the rivet manufacturing process, the authors of the present paper have developed an approach for shortening the process chain by omitting the heat treatment and rivet coating. To do this, use is made of high nitrogen steel as the rivet material. Successful joining with these rivets has already been proven, and it has also been shown that a competitive joint strength can be achieved with these rivets. Up until now, no studies have been conducted of the corrosion behaviour of uncoated rivets in high nitrogen steel compared to conventional rivets made of heat-treatable steel with a coating of Almac® or zinc-nickel with topcoat, and the corrosion behaviour of joints manufactured with these rivets has also not been investigated. Furthermore, the suitability of rivets in high nitrogen steel for structures undergoing cathodic dip painting has not been evaluated to date. These are therefore the aims of the research work presented in this paper. Corrosion behaviour is tested by exposing rivets and joints to a salt spray atmosphere. Cross-cut tests are conducted in order to classify the adhesion of cathodic dip paint to the different rivet surfaces and materials. The results of the experimental test show that the cathodic dip paint has sufficient adhesion to the uncoated rivets in high nitrogen steel and that these rivets can therefore be used in the manufacture of car bodies. Due to the stainless properties of the high nitrogen steel, better corrosion resistance is seen by comparison to the commonly used coatings of Almac® and zinc-nickel with topcoat. A study of the corrosion behaviour of the joints shows that the rivet head diameter and rivet head position, in particular, are decisive for preventing crevice corrosion under the rivet head and contact corrosion within the joint. }},
author = {{Uhe, Benedikt and Kuball, Clara-Maria and Merklein, Marion and Meschut, Gerson}},
journal = {{Production Engineering}},
title = {{{Corrosion behaviour of self-piercing riveted joints with uncoated rivets in high nitrogen steel}}},
doi = {{10.1007/s11740-024-01262-6}},
year = {{2024}},
}
@inproceedings{55638,
abstract = {{Abstract. Traditionally, joints are cylindrical and rotationally symmetric. In the present study, non-rotationally symmetric joints are used for joining steel and Glass mat-reinforced thermoplastic sheets (GMT). In addition, the study also analyzes the impact of non-rotational symmetric joint rotation on the load-bearing capacity. Single lap joint specimens were fabricated using the In-Mold assembly technique for joining steel sheets with GMT. Tensile shear tests were performed on different orientations of the joint geometry, and it was observed that changing the joint orientation influences the load-bearing capacity. The joints are constitutively modeled using beam elements and the influence of joint rotation on load distribution is examined through a static simulation study. }},
author = {{Devulapally, Deekshith Reddy and Martin, Sven and Tröster, Thomas}},
booktitle = {{Materials Research Proceedings}},
issn = {{2474-395X}},
publisher = {{Materials Research Forum LLC}},
title = {{{Non-rotationally symmetric joints – Mechanisms and load bearing capacity}}},
doi = {{10.21741/9781644903131-183}},
year = {{2024}},
}