TY - GEN A1 - Kriegel-Schmidt, Katharina A1 - Schmidt, Klaus T1 - Kultur als Blickwinkel in interkulturell orientierten Lernsettings : didaktische und theoretische Reflexionen am Beispiel einer Ausbildung in Interkultureller Mediation T2 - Interculture Journal Y1 - 2014 SN - 2196-9485 VL - 13 IS - 22 SP - 27 EP - 44 ER - TY - RPRT A1 - Becker, Jörg A1 - Clare, Lee A1 - Dietrich, Oliver A1 - Köksal-Schmidt, Çiğdem A1 - Merbach, Anja A1 - Notroff, Jens A1 - Pant, Smriti A1 - Peters, Joris A1 - Pöllath, Nadja A1 - Schmidt, Klaus T1 - Göbekli Tepe Newsletter 2014 Y1 - 2015 UR - http://www.dainst.org/documents/10180/123677/Newsletter+G%C3%B6bekli+Tepe+Ausgabe+1-2014 PB - German Archaeological Institute, Press Office CY - Berlin ER - TY - CHAP A1 - Kriegel-Schmidt, Katharina A1 - Schmidt, Klaus T1 - Programmatische Achsen einer kulturwissenschaftlichen Erforschung von Mediation T2 - Mediation als Wissenschaftszweig. Im Spannungsfeld von Fachexpertise und Interdisziplinarität Y1 - 2017 SN - 978-3-658-18256-4 SP - 57 EP - 70 PB - Springer CY - Berlin ER - TY - CHAP A1 - Rheidt, Klaus A1 - Schmidt, Leo ED - Zimmer, Kathrin Barbara T1 - Vom Denkmal zur Rekonstruktion T2 - Von der Reproduktion zur Rekonstruktion - Umgang mit Antike(n) II : Summerschool vom 16. - 19. Juni 2014 in Tübingen Y1 - 2016 SN - 978-3-89646-912-0 SP - 9 EP - 21 PB - VML, Verlag Marie Leidorf GmbH CY - Rahden/Westf. ER - TY - GEN A1 - Xie, Tianxiao A1 - Starick, Tommy A1 - Mosgow, Anatol A1 - Berg, Heinz Peter A1 - Höschler, Klaus A1 - Schmidt, Heiko T1 - Thermofluiddynamic pre-design of a primary surface heat exchanger under the influence of heat radiation using 1D/3D coupled simulation method T2 - NAFEMS World Congress 2021, online, 25-29. Oktober 2021 N2 - Within the Framework of the "TurboFuelCell (TFC)" a highly integrated and compact energy conversion system based on Micro Gas Turbine Solid Oxide Fuel Cell (MGT-SOFC) hybrid process is being developed by the team at BTU-Cottbus Senftenberg. This work focuses on the extension of the pre-design process of a primary surface heat exchanger (PSHX), which is a key component for the coupling between MGT and SOFC, using an 1D/3D hybrid simulation method for the understanding of its behaviour under the influence of heat radiation. In a MGT-SOFC hybrid process the high temperature heat exchanger plays an important role in preheating the fresh air to a minimum operation temperature necessary for SOFC. Due to the special location of this PSHX in the TFC, it is constantly exposed to heat radiation from the SOFC module, which requires additional consideration of its influence for better model accuracy. A first design, which is later extended through an 1D Flow network model, based on 𝜖 − 𝑁𝑇𝑈 method is presented. A complete 3D-CFD simulation with consideration of heat radiation is initially employed for the whole flow process to examine the first design. However, this approach proves to be highly computationally expensive due to the large dimensional difference between the plenum for cathode exhaust air and the fine channels in the PSHX. To reduce the computational effort, the flow and heat transfer in the PSHX is modelled by 1D elements. The flow in the plenum is simulated by 3D-CFD, which better accounts for convection and thermal radiation. A comparison between 3D-CFD and 1D/3D hybrid model is performed. A significant reduction of simulation time and computing resources can be achieved for well calibrated hybrid model without compromising on accuracy. In the talk, the effect of insulation layer thickness variations on the heat transfer on the plenum side due to heat radiation and their influence on the heat exchanger efficiency are discussed. Consequently, design improvements are realized based on the previous findings. Finally, the 1D/3D hybrid simulation method is evaluated and prepared for the general applications in thermal management of machines based on coupled MGT-SOFC process. Y1 - 2021 UR - https://www-docs.b-tu.de/fg-stroemungsmodellierung/public/Starick_2021_NAFEMS_World_Congress_Manuscript.pdf UR - https://agenda.nwc21.org/session.php?s=B5 ER - TY - RPRT A1 - Schmidt, Peer A1 - Donath, Ines A1 - Wels, Martin A1 - Pinnau, Sebastian A1 - Grau Turuelo, Constantino A1 - Breitkopf, Cornelia A1 - Hack, Klaus A1 - Baben, Moritz to A1 - Reis, Bruno A1 - Müller, Michael A1 - Sergeev, Dmitry A1 - Qi, Jia T1 - PCM Screening - Evaluierung eutektischer Gemische für den Einsatz als PCM: thermodynamische Modellierung und experimentelle Methoden : Energie Speicher: PCM-Screening : Schlussbericht N2 - Ein wichtiges Ziel der Bundesregierung ist der Ausbau des Anteils erneuerbarer Energien an der gesamten Stromerzeugung. Die Entwicklung optimierter Wärme- und Kältespeicher stellt einen wichtigen Baustein bei der Erreichung dieser Zielstellung dar. Elektrisch betriebene Wärmepumpen und Kompressionskältemaschinen sowie dezentrale Klein-BHKW bieten in Verbindung mit entsprechend dimensionierten, thermischen Speichern ein großes Potential zum Lastmanagement in Smart Grids und somit zur Netzintegration von Strom aus erneuerbaren Energien. Die im Projekt entwickelte Methodik zur Suche nach neuen Latentspeichermedien kann für ein breites Anwendungsfeld von Heiz- und Kühlanwendungen in Gebäuden bis hin zur Kraftwerkstechnik eingesetzt werden. Innerhalb der Fördermaßnahme „Anwendungsorientierte Forschung und Entwicklung zur nichtnuklearen Energieforschung“ im 6. Energieforschungsprogramm der Bundesregierung wurde durch die Projektarbeiten das Schwerpunktthema Energiespeicher (3.8) adressiert, wobei der Aspekt der Entwicklung neuer Materialien mit reduzierten Kosten für einen wirtschaftlichen Betrieb im Vordergrund stand. Speziell wurden dabei die Unterpunkte 3.8.4 Thermische Speicher zur Weiterentwicklung, Optimierung und Erprobung von PCM sowie 3.8.5 Übergeordnete Themen mit Modellen und Simulationswerkzeugen für die Auswahl und Bewertung neuer Speichermaterialien adressiert. Die Projektergebnisse besitzen aber auch Berührungspunkte mit den Schwerpunkten 3.12 Energieeffizienz in Industrie, Gewerbe, Handel und Dienstleistungen sowie 3.4 Solarthermische Kraftwerke, da mit der entwickelten Screening-Methode für diese Anwendungsfälle neue Wärmespeichermaterialien auf der Basis wasserfreier Salze mit höheren Prozesstemperaturen gefunden werden können. Durch den Einsatz von Methoden zur Modellierung und Simulation von Prozessen erfolgt gleichermaßen die Umsetzung einer energie- und ressourcenschonenden Forschungstätigkeit. Das im Projekt entwickelte Vorgehen hilft dabei, einen äußerst sparsamen Einsatz von Chemikalien, eine niedrige Belastung der Umwelt durch verringerten Entsorgungsaufwand der verbrauchten Stoffe sowie einen deutlich geringeren Aufwand und Energieeinsatz für die Messtechnik zu ermöglichen. Damit wurde zugleich das Schwerpunktthema 3.8.5 Modelle und Simulationswerkzeuge für die Auswahl und Bewertung neuer Speichermaterialien angesprochen. KW - Latentwärmespeicher KW - Phase diagram KW - Thermodynamic modeling KW - Thermal analysis Y1 - 2021 UR - https://www.tib.eu/de/suchen/id/TIBKAT:177643451X/ U6 - https://doi.org/10.2314/KXP:177643451X PB - TIB – Leibniz-Informationszentrum Technik und Naturwissenschaften CY - Hannover ER - TY - GEN A1 - Florian, Tobias A1 - Schricker, Klaus A1 - Zenz, Constantin A1 - Otto, Andreas A1 - Schmidt, Leander A1 - Diegel, Christian A1 - Friedmann, Hannes A1 - Seibold, Marc A1 - Hellwig, Peter A1 - Fröhlich, Fabian A1 - Nagel, Falk A1 - Kallage, Peter A1 - Buttazzoni, Michele A1 - Rack, Alexander A1 - Requardt, Herwig A1 - Chen, Yunhui A1 - Bergmann, Jean Pierre T1 - Combining in situ synchrotron X-ray imaging and multiphysics simulation to reveal pore formation dynamics in laser welding of copper T2 - International Journal of Machine Tools and Manufacture N2 - Laser beam welding has emerged as a powerful tool for manufacturing copper components in electrical vehicles, electronic devices or energy storage, owing to its rapid processing capabilities. Nonetheless, the material’s high thermal conductivity and low absorption of infrared light can introduce process instabilities, resulting in defects such as pores. This study employs a hybrid approach that combines in situ synchrotron X-ray imaging with compressible multiphysics process simulation to elucidate pore-forming mechanisms during laser beam welding of copper. High-speed synchrotron X-ray imaging with an acquisition rate of 20,000 images/second facilitates the identification of relevant process regimes concerning pore formation during laser beam welding of copper with a wavelength of 1070 nm. Furthermore, in situ observations with high temporal and spatial resolution present a unique database for extensive validation of a multi-physics process simulation based on welding processes using different concentric intensity distributions. These validated simulation results enable thorough comprehension of process-related pore formation based on the interaction between keyhole, melt pool and resulting flow field. The findings show that pore formation is driven by four different mechanisms: bulging, spiking, upwelling waves at the keyhole rear wall and melt pool ejections. The synergy of high- speed synchrotron X-ray imaging and multi-physics modeling provides a fundamental understanding of the chronological sequence of events leading to process-related pore formation during laser beam welding of copper. KW - In situ high-speed synchrotron X-ray imaging KW - Multi-physics simulation KW - Laser beam welding KW - Copper KW - Pore formation KW - Concentric intensity distributions Y1 - 2025 U6 - https://doi.org/10.1016/j.ijmachtools.2024.104224 SN - 0890-6955 VL - 204 SP - 1 EP - 22 PB - Elsevier BV ER - TY - GEN A1 - Walther, Dominik A1 - Schmidt, Leander A1 - Räth, Timo A1 - Schricker, Klaus A1 - Bergmann, Jean Pierre A1 - Sattler, Kai-Uwe A1 - Mäder, Patrick T1 - Deep learning-driven active sheet positioning using linear actuators in laser beam butt welding of thin steel sheets T2 - Journal of advanced joining processes N2 - Welding thin steel sheets in industrial applications is difficult because joint gaps occur during the process, which can lead to weld interruptions. Such welds are considered a reject and in order to avoid the weld to interrupt it is crucial to hinder the formation of joint gaps. Especially laser beam welding is affected by the emergence of gaps. Due to the narrow laser spot, product quality is highly dependent on the alignment and positioning of the sheets. This is typically done by clamping devices, which hold the workpieces in place. However, these clamps are suited for a specific workpiece geometry and require manual redesign every time the process changes. Adaptive clamping devices instead are designed to realize a time-dependent workpiece adjustment. Modeling the joint gap behavior to realize a controller for adaptive clamps can be difficult as the influence of heating, melting, and cooling on the joint gap formation is unknown and varies due to temperature dependent physical properties. Instead, the control parameters and actions can be derived using data-driven methods. In this paper, we present a novel data-driven approach how deep learning can be utilized to manipulate the sheet position during the weld with two actuators that apply force. A temporal convolution neural network (TCN) analyzes the change of the joint gap and predicts the required force to adapt the workpiece position. The developed method has been integrated into the welding process and improves the length of the average weld seam by 39.5% compared to welds without an active adjustment and 1.4% to welds that have been adapted with a constant force. KW - Laser beam welding KW - Temporal convolutional neural network KW - Thin steel sheets KW - Inductive probes KW - Gap adjustment KW - Deep learning Y1 - 2025 U6 - https://doi.org/10.1016/j.jajp.2025.100303 SN - 2666-3309 VL - 11 SP - 1 EP - 12 PB - Elsevier BV CY - Amsterdam ER - TY - GEN A1 - Walther, Dominik A1 - Schmidt, Leander A1 - Schricker, Klaus A1 - Junger, Christina A1 - Bergmann, Jean Pierre A1 - Notni, Gunther A1 - Mäder, Patrick T1 - Dataset for weld seam analysis and discontinuity prediction in laser beam welding scenarios T2 - Data in brief N2 - Laser beam welding can produce narrow, high-quality welds in various industrial joining processes. The thermal expansion and contraction of the metal during the weld results in the displacement of the sheets. That leads to the formation of joint gaps and subsequent to a process interruption. This behavior has only been analyzed to a limited extent and causes manufacturers to rely on heavy clamping systems rather than using more flexible fixtureless approaches. Due to the time-consuming and costly nature of recording and producing erroneous weld seams, such recordings and datasets are rarely available in this area. This often limits the research towards adaptable fixtureless welding setups. Because of this, we present a multi-modal dataset consisting of 100 recorded welds that tracks the metal sheets movement. The developed setup enables the determination of boundary conditions for fixtureless welding. Two types of sensors record the welding process. First, three inductive probes are applied to record the metal sheets` movement and second, a long-wave infrared (LWIR) camera records changes in the thermal radiation field. Two different welding speeds and laser powers were used to produce a variety of welds. The dataset can be used for data-driven algorithms to predict the metal movement, analyze the thermal radiation field, or develop quality control methodologies. KW - Laser Beam Butt Welding KW - Inductive Probes KW - LWIR Camera KW - Time Series KW - Images KW - Thin Steel Sheets KW - Classification KW - Regression Y1 - 2025 U6 - https://doi.org/10.1016/j.dib.2025.111381 SN - 2352-3409 VL - 59 SP - 1 EP - 8 PB - Elsevier BV CY - Amsterdam ER - TY - GEN A1 - Diegel, Christian A1 - Schricker, Klaus A1 - Schmidt, Leander A1 - Seibold, Marc A1 - Friedmann, Hannes A1 - Hellwig, Peter A1 - Fröhlich, Fabian A1 - Nagel, Falk A1 - Kallage, Peter A1 - Rack, Alexander A1 - Requardt, Herwig A1 - Chen, Yunhui A1 - Bergmann, Jean Pierre T1 - In situ characterization of keyhole behavior and spatter formation in full penetration laser beam welding with local gas flow using high-speed synchrotron X-ray imaging T2 - Optics & laser technology N2 - Spatter formation is a major issue at welding speeds above 8 m/min for full penetration laser beam welding of high-alloyed steels. In experiments using a local gas flow directed at the keyhole rear wall, a reduction in spatter formation on the specimen top side was observed for welding of AISI 304. However, the interaction between gas flow and keyhole behavior with respect to the mechanisms and locations of spatter detachment, especially on the bottom side, is not yet fully understood. High-speed synchrotron X-ray imaging enables detailed insights into the keyhole behavior and the spatter formation to obtain a deeper understanding of the underlying mechanisms. During the reference experiments welding without shielding gas flow, the spatter detach from a melt pool swelling behind the keyhole aperture on both sides of the sheet. A gas flow with a low flow rate of 4.8 L/min reduces the spatter formation on the top side and the keyhole length due to the absence of oxygen affecting the surface tension. A swelling also forms on the keyhole front on the bottom side and small spatter detach undirected. Increasing the flow rate to 12.8 L/min elongates the keyhole, particularly on the specimen top side. The increased momentum transfer of the gas flow results in a periodic keyhole oscillation on the specimen top side. In combination with an elongated melt pool, the oscillation is directly correlated with the hump formation, caused by melt being pushed over the already solidified weld seam. In addition, spatter does not detach from the top side due to the changed melt flow and only detach from the keyhole front on the bottom side. KW - Laser welding KW - Spatter formation KW - Gas flow KW - High-speed X-ray imaging KW - Synchrotron KW - In situ Y1 - 2025 U6 - https://doi.org/10.1016/j.optlastec.2025.113367 SN - 0030-3992 VL - 191 SP - 1 EP - 17 PB - Elsevier BV CY - Amsterdam ER -