TY - GEN A1 - Nikitin, Alexander A1 - Turabov, Dashqin A1 - Ermilova, Evgeniia A1 - Evdokimov, Anton A1 - Ossenbrink, Ralf A1 - Seidlitz, Holger T1 - Using dynamic resistance to predict electrode surface degradation in resistance spot welding of 5182 aluminum alloy T2 - Welding in the World N2 - In this study, the correlation between dynamic resistance during the first 10 ms of welding time and the electrode surface condition in resistance spot welding of 5182 aluminum alloy has been investigated. The electrode surface rapidly degrades due to contamination and morphological changes, adversely affecting the weld spot surface. The accumulation of Cu-Al intermetallic phases on the electrode surface alters its roughness, leading to variations in dynamic resistance. By analyzing this correlation, optimal electrode milling intervals were identified to extend electrode life. This work focused on detecting crater formation on the electrode surface through dynamic resistance monitoring. The results indicate that resistance measurements provide a reliable approach for evaluating electrode wear, optimizing maintenance schedules, and reducing material removal during milling. KW - resistance spot welding KW - aluminum alloy KW - electrode wear KW - dynamic resistance KW - electrode surface Y1 - 2024 U6 - https://doi.org/10.1007/s40194-024-01872-9 VL - 69 SP - 449 EP - 458 ER - TY - GEN A1 - Rüppel, Gernot Wilhelm A1 - Dorn, Oliver Niklas A1 - Kuke, Felix A1 - Ulke-Winter, Lars A1 - Seidlitz, Holger T1 - Optical tape detection using an IR camera to create a digital twin of rotationally symmetrical wet-wound FRP components T2 - Journal of Engineering 360 N2 - Wet-winding is used to manufacture rotationally symmetrical components such as pipes and pressure vessels, as well as non-rotationally symmetrical components like T-connectors. During this process, a resin-impregnated fiber (e.g., glass or carbon fiber) is wound around a core. The winding pattern influences the mechanical properties, including stiffness and strength of the component, and is optimized based on the expected loads. In practice, however, factors such as tape tension and resin content can cause deviations from the predefined winding pattern. This paper proposes a measuring system utilizing an IR-camera to record the winding pattern during production. The collected data is processed and converted into a digital twin for further analysis. KW - digital twin KW - wet winding KW - IR-Camera KW - optical fiber detection KW - optical tape detection Y1 - 2024 U6 - https://doi.org/10.5604/01.3001.0054.8851 SN - 3071-7507 VL - 1 (2024) IS - 1/24 SP - 46 EP - 57 PB - Index Copernicus ER - TY - GEN A1 - Sztorch, Bogna A1 - Romanczuk-Ruszuk, Eliza A1 - Głowacka, Julia A1 - Kustosz, Magdalena A1 - Osiecki, Tomasz A1 - Jakubowska, Paulina A1 - Seidlitz, Holger A1 - Przekop, Robert E. T1 - Improving the processing and mechanical properties of 3D printable biocomposite based on polylactide, sediment rock, and natural beeswax T2 - Polymer Bulletin N2 - Polylactide is a material often used in additive techniques. Due to poor mechanical properties, there is a constant search for additives, fillers, and modifiers that could improve these properties. Natural fillers and additives are promising compounds because they can improve the properties of the composite and at the same time are environmentally friendly. This work concerns the first-time modification of PLA using the Opoka sedimentary rock, modified with natural beeswax and commercially available wax. The addition of sedimentary rock caused the natural color of the obtained fibers, and it was found that the Opoka addition has a positive effect on the processing and printing parameters, allowing for a significant reduction in the operating temperature and the extrusion and printing speed, as well as better interlayer adhesion and adhesion to the printer bed, which is particularly important in the case of 3D printing. The obtained materials were characterized by a higher degree of crystallinity, and better mechanical and surface parameters (significantly higher contact angles and hydrophobic properties). KW - PLA KW - Sediment rock KW - Opoka KW - FDM KW - Waxes KW - 3D Printing Y1 - 2024 U6 - https://doi.org/10.1007/s00289-024-05614-1 SN - 0170-0839 VL - 2024 PB - Springer Science and Business Media LLC ER - TY - GEN A1 - Ost, Lucas A1 - Seidlitz, Holger A1 - Ulke-Winter, Lars A1 - Kuke, Felix T1 - Development of a spherical high‐pressure tank for hydrogen storage in mobile and stationary applications T2 - Energy Technology N2 - In the sub‐project Mukran of the BMBF‐funded flagship project TransHyDE, spherical and nearly spherical‐shaped (isotensoids with short cylindrical spacer) high‐pressure tanks are developed for hydrogen storage. This article presents the planned work of the Chair of Polymer‐based Lightweight Design at the BTU Cottbus–Senftenberg and the research division PYCO at the Fraunhofer IAP. The research topics include the fiber‐compatible design of the liners, the rule‐based optimization of the layer structure of the load‐bearing overwrap made of carbon fiber‐reinforced plastic, the development of a fiber placement strategy, and the integration of the tanks into a frame as a mobile storage solution. KW - CFRP pressure vessel KW - hydrogen KW - pressure vessel KW - spherical pressure vessel Y1 - 2024 U6 - https://doi.org/10.1002/ente.202300942 SN - 2194-4288 PB - Wiley ER - TY - GEN A1 - Hajhariri, Aliasghar A1 - Eberwein, Robert A1 - Perrone, Luca Pakj A1 - Cozzani, Valerio A1 - Otremba, Frank A1 - Seidlitz, Holger T1 - Study the impact of spacer at thermal degradation process of MLI-based insulation in fire condition T2 - Journal of Loss Prevention in the Process Industries N2 - To reduce CO2 emissions, energy carriers such as hydrogen are considered to be a solution. Consumption of hydrogen as a fuel meets several limitations such as its low volumetric energy density in gas phase. To tackle this problem, storage as well as transportation in liquified phase is recommended. To be able to handle this component in liquid phase, an efficient thermal insulation e.g., MLI insulation is required. Different studies have been addressed the vulnerability of such insulation against high thermal loads e.g., in an accident engaging fire. Some of research works have highlighted the importance of considering the MLI thermal degradation focusing on its reflective layer. However, limited number of studies addressed the thermal degradation of spacer material and its effect on the overall heat flux. In this study, through systematic experimental measurements, the effect of thermal loads on glass fleece, glass paper as well as polyester spacers are investigated. The results are reported in various temperature and heat flux profiles. Interpreting the temperature profiles revealed that, as the number of spacers in the medium increases, the peak temperature detectable by the temperature sensor on the measurement plate decreases. Each individual spacer contributes to mitigating the radiative energy received by the measurement plate. Stacks of 20–50 spacers (this is the number of layers in commercial MLI systems applied for liquid hydrogen applications) can potentially reduce the thermal radiation by 1–2 orders of magnitude. An empirical correlation to predict a heat flux attenuation factor is proposed, which is useful for further numerical and analytical studies in the temperature range from ambient to 300 °C. KW - Liquefied hydrogen KW - Liquefied natural gas KW - Cryogenic storage tank KW - Thermal insulation KW - Multi-Layer Insulation KW - Microspheres KW - Perlite Y1 - 2024 U6 - https://doi.org/10.1016/j.jlp.2024.105461 SN - 0950-4230 VL - 92 SP - 240 EP - 248 PB - Elsevier BV ER - TY - GEN A1 - Seidlitz, Holger A1 - Ost, Lucas A1 - Ambrosio, Marcello A1 - Kuke, Felix A1 - Michailov, Vesselin A1 - Shapovalov, Oleg A1 - Doynov, Nikolay T1 - Erwärmung von Composites simulieren T2 - Kunststoffe N2 - Neuartige, werkstoffgerechte Fügeverfahren für Faserkunststoffverbunde setzen die Erwärmung der Materialien voraus. Um die damit verbundenen komplexen Temperaturfelder und -verläufe vorherzusagen, haben das Fraunhofer IAP und die BTU Cottbus-Senftenberg numerische Verfahren entwickelt. Mit diesen können auch verschiedene Strahlungsquellen und Prozessabläufe simuliert werden. KW - Faserkunststoffverbunde KW - Fügen KW - Simulation Y1 - 2023 UR - https://www.kunststoffe.de/a/article-3363044 SN - 0023-5563 IS - 2 SP - 66 EP - 70 ER - TY - GEN A1 - Shapovalov, Oleg A1 - Ost, Lucas A1 - Kuke, Felix A1 - Doynov, Nikolay A1 - Ambrosio, Marcello A1 - Seidlitz, Holger A1 - Michailov, Vesselin T1 - Entwicklung und Analyse einer Fügestrategie für FKV/Metall-Mischverbindungen auf Basis der CMT-Pinschweißtechnik T2 - Joining Plastics N2 - Dieser Beitrag stellt eine Entwicklung, Anpassung und Untersuchung der neuartigen Pinschweißtechnik zur Verbindung thermoplastischer Faserkunststoffverbunde mit metallischen Fügepartnern dar. Die untersuchte Fügetechnik bietet, im Vergleich zu anderen Verfahren, neben einer einseitigen Zugänglichkeit, ein hohes Leichtbaupotenzial. An Multimaterial-Einzelpinverbindungen wurden die CMT-Pinschweißbarkeit charakterisiert und unterschiedliche Fügestrategien erprobt und ausgewertet. Als Bewertungskriterien wurden das Schweißgut sowie der Faser- und Matrixerhalt in Abhängigkeit von den Schweißparametern untersucht. Die mechanische Beanspruchbarkeit der mit dem entwickelten Verfahren erstellten Verbindungen wurde in Scherzugversuchen ermittelt. An Mehrpinverbindungen wurde anschließend der Einfluss der Pinanordnung untersucht und die Auslegung der Fügezone analysiert. Der Fügeprozess wurde an Funktionsmustern und diese wiederum in 3-Punkt-Biegeversuchen validiert sowie mit dem Kleben verglichen. Y1 - 2023 UR - https://www.joining-plastics.info/artikel/entwicklung-und-analyse-einer-fuegestrategie-fuer-fkvmetall-mischverbindungen-auf-basis-der-cmt-pinschweisstechnik SN - 1864-3450 VL - 17 IS - 1 SP - 28 EP - 35 ER - TY - GEN A1 - Seidlitz, Holger A1 - Michailov, Vesselin A1 - Ost, Lucas A1 - Kuke, Felix A1 - Ambrosio, Marcello A1 - Shapovalov, Oleg A1 - Doynov, Nikolay T1 - Simulation of Composites’ Heating T2 - Kunststoffe international N2 - Modern material-compatible joining methods for fiber-reinforced plastics require the heating of the materials. In order to predict the respective complex temperature fields and curves, the Fraunhofer IAP and the BTU Cottbus-Senftenberg have developed numerical methods, which are able to simulate different radiation sources and process sequences as well. KW - Composites KW - Simulation KW - Joining of Fiber-Reinforced Plastic Composites Y1 - 2023 UR - https://epaper.kunststoffe.de/en/read/26/26/2023-05-26/1 SN - 1862-4243 VL - 113 IS - 4 SP - 60 EP - 64 ER - TY - GEN A1 - Bledzki, Andrzej K. A1 - Seidlitz, Holger A1 - Goracy, Krzysztof A1 - Urbaniak, Magdalena A1 - Rösch, Janina J. T1 - Recycling of Carbon Fiber Reinforced Composite Polymers—Review—Part 1: Volume of Production, Recycling Technologies, Legislative Aspects T2 - Polymers KW - carbon fibers KW - polymer composites KW - recycling KW - recycled carbon fibers Y1 - 2021 U6 - https://doi.org/10.3390/polym13020300 SN - 2073-4360 VL - 13 IS - 2 ER - TY - GEN A1 - Bledzki, Andrzej K. A1 - Seidlitz, Holger A1 - Krenz, Jonas A1 - Goracy, Krzysztof A1 - Urbaniak, Magdalena A1 - Rösch, Janina J. T1 - Recycling of Carbon Fiber Reinforced Composite Polymers—Review—Part 2: Recovery and Application of Recycled Carbon Fibers T2 - Polymers KW - polymer composites KW - recycled carbon fibers KW - recycling KW - automotive industry KW - railways KW - aviation KW - wind turbine Y1 - 2020 U6 - https://doi.org/10.3390/polym12123003 SN - 2073-4360 VL - 12 IS - 12 ER -