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 - TY - GEN A1 - Hajhariri, Aliasghar A1 - Eberwein, Robert A1 - Camplese, Davide A1 - Scarponi, Giordano Emrys A1 - Cozzani, Valerio A1 - Otremba, Frank A1 - Seidlitz, Holger T1 - Non-Combustible MLI Based Insulation Behavior Under Fire Condition - Experimental and Numerical Investigation T2 - Process Safety and Environmental Protection N2 - The number of applications that demand zero-emission energy carriers, such as liquified hydrogen (LH2), is increasing worldwide. LH2 is typically transported or stored under cryogenic conditions. Storage in such conditions requires super thermal insulations which maintain very low boil-off for a prolonged time. Multi-Layer insulation (MLI) finds widespread use in cryogenic applications, designed to effectively restrict heat inleak towards cryogenic fluids. However, recent studies evidenced that exposure to high heat fluxes, such as in the event of a fire accident, can cause the thermal degradation of the insulation material, resulting in the severe collapse of its heat resistance performance. Therefore, the risk of rapid tank pressurization and its connection to the risk of BLEVE may be possible. This study proposes a numerical model to assess the performances of aluminum-based MLI materials under fire conditions. The model offers insights into the total heat transfer rate through the insulation, serving as an indicator of the deterioration's impact on overall heat transfer. The proposed numerical model is validated against experimental data obtained by a High-Temperature Thermal Vacuum Chamber test facility that reproduces fire exposure conditions. The experiments conducted in this study underscore the emergence of pressure build-up within the insulation system, which contributes to increased gas conduction. Furthermore, it demonstrates that the spacer material is not entirely damaged under simulated fire conditions. The numerical calculation also underscores the significance of the modifications in material surface emissivity due to the deterioration process. The innovative approach proposed in this study thus paves the way for the development of improved tools aiming at the stationary and mobile cryogenic tanks behavior (e.g., LNG, LOX, LN2, and LH2) in fire accident scenarios. The model developed may, in perspective, be integrated into both CFD and lumped models for the calculation of the time to failure of cryogenic equipment under external fires. Therefore, this study offers valuable insights to improve the safety of processes and equipment for the storage of cryogenic fluids, thereby supporting emergency response planning in case of fire accidents. KW - Multi-Layer Insulation (MLI) KW - Cryogenic Vessels KW - Liquefied Hydrogen Y1 - 2024 U6 - https://doi.org/10.1016/j.psep.2024.11.037 SN - 0957-5820 VL - 193 SP - 403 EP - 420 PB - Elsevier BV ER - TY - GEN A1 - Seidlitz, Holger A1 - Hajhariri, Aliasghar A1 - Eberwein, Robert A1 - Perrone, Luca Pakj A1 - Cozzani, Valerio A1 - Otremba, Frank ED - Di Benedetto, Almerinda ED - Portarapillo, Maria T1 - Study the Impact of Spacer at Thermal Degradation Process of MLI-based Insulation in Fire Condition T2 - Proceedings of the 15th International Symposium on Hazards, Prevention and Mitigation of Industrial Explosions N2 - To reduce carbon dioxide emissions, energy carries such as hydrogen consider to be a solution. Consumption of hydrogen as a fuel meets several restrictions such as its low volumetric energy density in gas phase. To tackle this problem, storage as well as transportation in liquid phase is recommended. To be able to handle this component in liquid phase, an efficient thermal insulation e.g., MLI insulation is required. Some studies have been revealed vulnerability of this type of insulation against high heat flux, for instance a fire accident. Some investigations have been depicted the importance of consideration of the MLI thermal degradation in terms of its reflective layer. However, limited number of studies have been focused on 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 as the number of spacers in the medium increases, the peak temperature detectable by the temperature sensor on the measurement plate decreases. Moreover, the contribution of each individual spacer in all cases regarding the experimental temperature range is assessed to be around 8%. This value may increase to around 50% for glass paper and polyester spacers, and to around 25% for glass fleece spacers as the number of spacer layers increases up to six layers. To utilize the outcomes of the experiment later and integrate the results into numerical and CFD simulations, a model is proposed for the mentioned experimental temperature range up to 300°C to predict a heat flux attenuation factor. The model proposes a fitting factor that can reproduce the least square fitted line to the experimental data. KW - Multi-Layer Insulation (MLI) KW - Cryogenic KW - Liquid Hydrogen KW - Heat transfer Y1 - 2024 UR - https://zenodo.org/records/12621001 U6 - https://doi.org/10.5281/zenodo.12621001 SP - 744 EP - 755 CY - Napoli, Italy ER - TY - PAT A1 - Seidlitz, Holger A1 - Ambrosio, Marcello A1 - Müller, Michael A1 - Hansen, Torsten T1 - Sandwichlaminatstruktur, deren Verwendung und ein Verfahren zur Verwendung der Sandwichlaminatstruktur N2 - Sandwichlaminatstruktur mit einer ersten und einer zweiten Oberfläche, die einander gegenüberliegen, umfassend ein Kernelement, das eine erste Oberfläche und eine der ersten Oberfläche gegenüberliegende zweite Oberfläche aufweist, mindestens zwei Heizschichten, von denen mindestens eine Heizschicht auf der ersten und mindestens eine Heizschicht auf der zweiten Oberfläche des Kernelements angeordnet ist, und mindestens zwei Gewebelagen, von denen jeweils mindestens eine Gewebelage jeweils auf der dem Kernelement abgewandten Seite der mindestens zwei Heizschichten angeordnet ist, wobei das Material des Kernelements als Wabenvlies ausgebildet ist, welches Polyesterfasern, Polyamidfasern, Polyetherfasern und/oder deren Mischungen umfasst, wobei an den mindestens zwei Heizschichten Anschlüsse für eine Spannungsquelle angeordnet sind und die mindestens zwei Heizschichten als Leitfähigkeitssensoren zur Leckageüberwachung dienen. KW - Sandwichlaminatstruktur KW - Heizschicht KW - Leckageüberwachung Y1 - 2024 ER - TY - GEN A1 - Seidlitz, Holger T1 - Das Runde muss ins Eckige - mobile Wasserstoff-Kugelspeicher sollen Energieversorgung fächendeckend sichern T2 - CU reports N2 - Dem Wasserstoff-Transport widmen sich im TransHyDE-Projekt Mukran sechs Partnerinstitutionen aus Wissenschaft und Wirtschaft. Gemeinsam entwickeln sie neuartige sphärische Wasserstoffhochdruckspeicher mit einer lasttragenden Hülle aus carbonfaserverstärktem Kunststoff (CFK). Diese bieten einen „optimalen Kompromiss aus belastungs- und funktionsgerechter Geometrie“ und ermöglichen – eingebaut in standardisierte Containerquader – einen effizienten Transport mit hohem Nutzlastverhältnis. KW - Sphärische Wasserstoffhochdruckspeicher KW - Wasserstofftransport KW - Kugeltank KW - Wickelprozess Y1 - 2024 UR - https://digitalmagazin.b4bschwaben.de/de/profiles/610b21560ff9/editions/938f18855a9b7f4385ee/pages/page/13 SN - 2699-4534 VL - 01/2024 IS - 1 SP - 24 EP - 25 ER - TY - GEN A1 - Błędzki, Andrzej A1 - Seidlitz, Holger A1 - Köhler, Mathias A1 - Urbaniak, Magdalena A1 - Demski, Szymon A1 - Boczkowska, Anna T1 - Reusing and recycling of composite wind turbine blades. A review of current practices and prospects. Part 4.** Novel academic research T2 - Przemysł chemiczny N2 - A review, with 21 refs., of new resins for manufacturing, repair methods and recycling possibility stds. for established end-of-life management published in last 2 years. KW - Polymer composites KW - Wind turbine blades KW - High-performance wind turbines KW - Repair and recycling methods KW - End-of-life management KW - World’s largest wind turbines Y1 - 2025 U6 - https://doi.org/10.15199/62.2025.1.10 SN - 0033-2496 VL - 104 IS - 1 SP - 133 EP - 141 PB - Wydawnictwo SIGMA-NOT, sp. z.o.o. ER - TY - GEN A1 - Cieślik, Iwona A1 - Seidlitz, Holger A1 - Duchna, Monika A1 - Zasada, Dariusz A1 - Kwaśny, Mirosław A1 - Adamczyk-Cieślak, Bogusława T1 - Chemical method of doping Inconel 713C powder with rhenium for 3D printed manufacturing. Influence of rhenium dopants on the microstructure changes T2 - Archives of Civil and Mechanical Engineering N2 - A well-known method of doping powders in the industry is mechanical alloying synthesis. This method synthesizes metal powders by grinding them in high-energy mills, which prevents the achievement of well-dispersed particles throughout the volume and control of particle morphology, size, and agglomeration. In the present work, rhenium doping of IN 713C was carried out in a polyester network system based on organic acids and diols with specially selected catalysts and experimental parameters leading to the complexation of Rhenium ions. In addition, neutral reagents were used in this research, contributing to the greening of many key industries. The obtained IN 713C powder with rhenium showed high dispersion without agglomeration effect and reasonable flowability. Depending on the polymerization process parameters, the morphology of the rhenium particles on the surface of IN 713C can be modified. The IN 713C powder, with and without rhenium, was used in the SLM process to fabricate IN 713C alloy samples. The study examines the effect of rhenium doped IN 713C on the microstructure and hardness changes of the alloy produced by the 3D-printing methods. This type of chemical modification methods can effectively enhance the hardness and affects the elongation of dendrites in the structure of IN 713C alloys manufactured by the additive methods. KW - Rhenium KW - Chemical doping KW - Inconel 713C KW - Microstructure KW - 3D printing Y1 - 2025 U6 - https://doi.org/10.1007/s43452-025-01159-w SN - 2083-3318 VL - 25 IS - 2 PB - Springer Science and Business Media LLC ER - TY - GEN A1 - Popiela, Bartosz A1 - Günzel, Stephan A1 - Schukar, Marcus A1 - Mair, Georg W. A1 - Krebber, Katerina A1 - Seidlitz, Holger T1 - Impact of internal pressure control during manufacturing on residual stresses and safety performance of type 4 pressure vessels T2 - Composites Part C: Open Access N2 - Composite pressure vessels are commonly manufactured using the wet filament winding process, where various process parameters can influence the performance of the finished component. In this study two designs of wet filament wound 6.8-liter type 4 composite pressure vessels were manufactured. Both differ only by the internal pressure used during the filament winding, which primarily influences the residual stress state in the composite structure. An extensive experimental study was carried out, including 10 slow burst tests and strain measurements with fiber optic sensors. Significant differences can be observed in the performance of the two designs even though the used stacking sequence, materials and other manufacturing parameters are the same for both designs. A discussion of the differences in the behavior of both cylinder types is provided, including the strain distribution in slow burst tests and failure mechanism. KW - Residual stresses KW - Slow burst tests KW - Filament winding KW - Type 4 composite pressure vessels KW - Hydrogen Y1 - 2025 U6 - https://doi.org/10.1016/j.jcomc.2025.100581 SN - 2666-6820 VL - 17 PB - Elsevier BV ER - TY - JOUR A1 - Popiela, Bartosz A1 - Günzel, Stephan A1 - Sklorz, Christian A1 - Widjaja, Martinus Putra A1 - Mair, Georg W. A1 - Seidlitz, Holger T1 - Application of the incremental hole-drilling method for residual stress determination in type 4 pressure vessels JF - Materials Testing N2 - Hole-drilling method is a standardized technique for obtaining residual stresses in isotropic structures. Previous studies provide a foundation that enables the use of this method to investigate orthotropic structures, such as fiber-reinforced composites. In this study, the incremental hole-drilling method was applied to investigate residual stresses in filament wound type 4 composite pressure vessels. The investigated composite cylinders were manufactured with different internal pressure functions during the winding process, to achieve distinct residual stress states. Additionally, the influence of the initial loading under sustained internal pressure and increased temperature on the stress distribution was investigated. It was shown that the residual stress state can be influenced by varying the internal pressure in the winding process. After testing at sustained load and increased temperature, a stress redistribution was observed, which took place due to creep phenomena. Finally, a discussion of the challenges for the application of the hole-drilling method to composite pressure vessels is provided. KW - hole-drilling method KW - filament winding KW - type 4 composite pressure vessels KW - residual stresses KW - stress redistribution Y1 - 2025 U6 - https://doi.org/10.1515/mt-2024-0328 SN - 0025-5300 VL - 67 IS - 4 SP - 663 EP - 674 PB - Walter de Gruyter GmbH ER - TY - GEN A1 - Błędzki, Andrzej A1 - Seidlitz, Holger A1 - Köhler, Mathias A1 - Urbaniak, Magdalena A1 - Demski, Szymon A1 - Boczkowska, Anna T1 - Reusing and recycling of composite wind turbine blades. A review of current practices and prospects. Part 5**. New industrial projects. Wind energy in China T2 - Przemysł chemiczny N2 - A review, with 23 refs., of projects mainly from last 2 years currently commercialized by large consortia often in cooperation with academic teams. Many detail information about wind energy development and wind turbine blades recycling in China was delivered. KW - Polymer composites KW - Wind turbine blades KW - Currently project by large consortia KW - Wind energy in China KW - Comprehensive management methods Y1 - 2025 U6 - https://doi.org/10.15199/62.2025.1.11 SN - 0033-2496 VL - 104 IS - 1 SP - 142 EP - 152 PB - Wydawnictwo SIGMA-NOT, sp. z.o.o. ER - TY - JOUR A1 - Hartung, David A1 - Seidlitz, Holger A1 - Osiecki, Tomasz A1 - Sztorch, Bogna A1 - Przekop, Robert E. A1 - Kazimierczuk, Magdalena T1 - Flax fiber reinforced PET-G composites with improved interfacial adhesion JF - Polimery N2 - Recycled PET-G (rPET-G) composites reinforced with flax fiber were obtained. To improve interfacial adhesion, the fiber was treated by washing and finishing with bio-based epoxidized soybean oil and admixture acid. The effect of fiber surface treatment on its properties and those of the composites was evaluated by TGA, FT-IR and SEM, as well as by contact angle, flexural and tensile measurements. The results indicated delayed degradation of the treated flax fiber with a fiber mass loss of about 4 wt%. The flexural strength and modulus increased for the washed and finished flax fiber compared to the untreated one. While the tensile properties were influenced by structural effects resulting from the fiber treatment. These findings contribute to the development of more sustainable and high-performance natural fiber-reinforced thermoplastic composites. KW - natural fibers KW - composites KW - epoxidized soyabean oil KW - admergin acid Y1 - 2025 U6 - https://doi.org/10.14314/polimery.2025.2.4 SN - 2957-0263 VL - 70 IS - 2 SP - 113 EP - 123 PB - LUKASIEWICZ Research Network - Industrial Chemistry Research Institute CY - Warsaw ER - TY - GEN A1 - Seidlitz, Holger A1 - Gebhard, Johannes A1 - Stamp, Benno T1 - Nicht nur leicht, sondern auch recycelbar : Monomaterial ersetzt Multimaterialverbunde im Automobilinnenraum T2 - Kunststoffe N2 - Leichtbau spielt nicht nur bei Automobilen mit Verbrennungsmotoren, sondern auch bei Elektrofahrzeugen eine wichtige Rolle. Die dafür genutzten Materialverbunde lassen sich häufig jedoch nicht recyceln. Bei Mercedes-Benz setzt man deshalb seit Kurzem im Interieur auf Monomaterialsandwiche. Diese verbessern nicht nur die Recyclingfähigkeit, sondern bringen teilweise auch mehr Leistung. KW - Recycling KW - Monomaterial KW - Automobilinnenraum Y1 - 2025 UR - https://www.kunststoffe.de/a/fachartikel/nicht-nur-leicht-sondern-auch-recycelbar-6610346 UR - https://epaper.kunststoffe.de/read/24/24/2025-03-14/1 SN - 0023-5563 VL - 2025 IS - 03 SP - 18 EP - 21 PB - Carl Hanser Verlag CY - München ER - TY - GEN A1 - Seidlitz, Holger A1 - Gebhard, Johannes A1 - Stamp, Benno T1 - Not only lightweight, but also recyclable : mono-material replaces multi-material composites in car interiors T2 - Plastics insight N2 - Lightweight construction plays an important role not only in cars with combustion engines but also in electric vehicles. However, the composite materials used for this purpose are often not recyclable. Mercedes-Benz has therefore recently started developing mono-material sandwiches for the interior. These not only improve recyclability, but also increase performance in some cases. KW - Recycling KW - Mono-Material KW - Mercedes Benz KW - Lightweight Y1 - 2025 UR - https://en.kunststoffe.de/a/specialistarticle/not-only-lightweight-but-also-recyclable-6701555 SN - 2941-4202 VL - 2025 IS - 03 SP - 13 EP - 17 PB - Carl Hanser Verlag CY - München ER - TY - GEN A1 - Hajhariri, Aliasghar A1 - Eberwein, Robert A1 - Camplese, Davide A1 - Scarponi, Giordano Emrys A1 - Otremba, Frank A1 - Cozzani, Valerio A1 - Seidlitz, Holger T1 - A comprehensive numerical study of the behaviour of an LH2 storage tank in the event of a fire T2 - Chemical engineering transactions N2 - As the world moves towards green energy production, effective storage and transportation solutions become essential. To support this transition, energy carriers with minimal or zero environmental impact are required. Liquified hydrogen represents a promising candidate due to its emissions-neutral properties. However, its highly flammable nature necessitates adherence to strict safety codes and standards. Storing hydrogen often requires advanced super-insulation materials. To enhance the safety of cryogenic hydrogen storage tanks under extreme conditions, such as those encountered during fire accidents, it is crucial to understand the thermal behaviour of the tank. Predicting pressurization and potential failure in advance demands a robust and comprehensive model. However, still such models suffer lack of detailed heat transfer models which account for various sub-processes during an accident scenario. Hence, this study introduces a comprehensive model for the pressurization of cryogenic tanks equipped with multi-layer insulation (MLI) systemsin the event of fire, which comprises several sub-models. These sub-models account for heat transfer phenomena through the thermal insulation at nominal conditions and its thermal degradation during fire exposure, the fluid, the internal pressurization, and the performance of the pressure relief valve. This study provides valuable insights into the safety and the behaviour of hydrogen storage tanks under thermal loads. KW - Hydrogen safety KW - Heat transfer modelling KW - Cryogenic hydrogen storage KW - Super-insulation materials Y1 - 2025 SN - 979-12-81206-18-2 U6 - https://doi.org/10.3303/CET25116114 SN - 2283-9216 IS - 116 SP - 679 EP - 684 PB - AIDIC Servizi S.r.l. CY - Milano ER - TY - GEN A1 - Hajhariri, Aliasghar A1 - Eberwein, Robert A1 - Camplese, Davide A1 - Scarponi, Giordano Emrys A1 - Otremba, Frank A1 - Cozzani, Valerio A1 - Seidlitz, Holger T1 - Repeatable testing of a cryogenic storage tank with variable insulation material in fire like conditions T1 - Essais reproductibles d’un réservoir de stockage cryogénique revêtu de divers matériaux d’isolation dans des conditions similaires à celles d’un incendie T2 - Cryogenics 2025 : proceedings of the 18th IIR International Conference on Cryogenics N2 - For decarbonizing the energy industry and transport, cryogenic energy carriers have great potential. The storage takes place in tanks with thermal super-insulations, which are in application for decades, but there is only limited knowledge about its behaviour in a fire scenario. This represents a major incident that may generate extraordinary loads on the tank and its insulation system, and that eventually lead to a sudden tank failure. This paper presents a test rig called the Cryogenic High Temperature Thermal Vacuum Chamber (CHTTVC), which can be used to test typical thermal superinsulation’s under cryogenic and fire-like conditions in parallel. The test method makes it possible to measure the heat flow through the thermal superinsulation over time and to investigate the degradation behaviour of the insulation within a test. In the paper results from the first tests are presented. KW - Cryogenics KW - Insulation KW - Transport and handling of cryogenic fluids Y1 - 2025 U6 - https://doi.org/10.18462/iir.cryo.2025.0007 VL - 2025 PB - Institut International du Froid CY - Paris ER - TY - GEN A1 - Popiela, Bartosz A1 - Günzel, Stephan A1 - Oktaviany, Jennifer A1 - Widjaja, Martinus Putra A1 - Mair, Georg W. A1 - Seidlitz, Holger T1 - Influence of internal pressure regulation during filament winding on failure mechnism in type 4 pressure vessels : a case study T2 - Proceedings of the 11th International Conference on Hydrogen Safety (ICHS 2025) N2 - Hydrogen storage is a crucial part of the hydrogen value chain, particularly in terms of safety and social acceptance of hydrogen technologies. For on-board and transportation applications, hydrogen is commonly stored as a compressed gas in pressure vessels. Full composite wrapped Type 4 pressure vessels are especially beneficial due to their high weight-saving potential and their capability to withstand high working pressures. To maintain an appropriate safety level, the mechanical behavior of the composite structure has been the subject of investigation in numerous studies. In this study, the failure mechanisms of two designs of Type 4 cylinders are investigated. The two designs differ solely in the manufacturing process parameters, particularly the internal pressure applied during the filament winding process. Variations in internal pressure result in different residual stress states and changes in the quality of the composite structure. The stacking sequence, materials used, and other manufacturing parameters remain unchanged. The cylinders show different failure mechanisms in slow burst tests: one design fails in hoop windings, while the other one fails in helical windings, despite no stress exaggeration in the fiber direction being observed with embedded optical fibers or in numerical simulations. To explain the failure mechanisms, the quality of the cylinders is investigated. The results of X-ray computed tomography and pulse-echo investigation, highlight the complexity of the interactions between manufacturing process parameters, residual stresses, manufacturing quality, and the mechanical behavior of composite pressure vessels. Resin-rich areas in the composite material are identified as a possible cause of the differing failure mechanisms. KW - Burst test KW - Composite KW - Filament winding KW - Pressure vessel Y1 - 2025 SP - 1 EP - 12 PB - Korea Gas Safety Corporation (KGS) ER - TY - GEN A1 - Popiela, Bartosz A1 - Schukar, Marcus A1 - Breithaupt, Mathias A1 - Günzel, Stephan A1 - Mair, Georg W. A1 - Krebber, Katerina A1 - Seidlitz, Holger T1 - Embedding of fiber optic sensors under industrial conditions and distributed strain sensing in type 4 composite pressure vessels T2 - Proceedings of the 24th International Conference on Composite Materials (ICCM-24) N2 - The number of in-operation composite pressure vessels is increasing, partly due to their attractiveness for on-board compressed gas storage and transport applications. A possible way to maintain the highest safety levels is through the structural health monitoring of the composite cylinders. Here, the use of fiber optic sensors appears to be a promising approach. However, the integration of the optical fibers into the composite structure of a pressure vessel has been shown to be challenging. In this study, insights on the embedding of optical fibers in the composite structure under industrial conditions are provided. A protection concept for the ingress and egress of the optical fibers is presented. Finally, the results from destructive slow burst tests are evaluated, showing no clear trend in the impact of the embedded optical fibers on the performance of composite pressure vessels. KW - Composite KW - Fiber optic sensors KW - Filament winding KW - Pressure vessel Y1 - 2025 U6 - https://doi.org/10.5281/zenodo.18597801 SP - 3710 EP - 3717 PB - The University of Delaware CY - Newark, Delaware ER - TY - GEN A1 - Kepir, Yusuf A1 - Seidlitz, Holger A1 - Ulke-Winter, Lars A1 - Felix, Kuke T1 - Lightweight heat exchanger design using graphene-reinforced ceramics : a comparative study of dimensional and material effects T2 - Proceedings of the 4th International Online Conference on Materials, 3–6 November 2025 N2 - In high-temperature environments, heat exchangers require lightweight designs, high thermal resistance, and high effectiveness. Graphene-reinforced ceramic matrix composites (G-CMC) offer promising thermal properties for such applications. This study investigates the effectiveness changes of a block-type heat exchanger made of G-CMC, depending on the length and design, leveraging the potential of 3D printing in the production of complex geometries. KW - Ceramic matrix composite KW - Heat exchanger KW - Numerical analysis KW - Heat transfer KW - Thermal effectiveness Y1 - 2025 UR - https://sciforum.net/paper/view/25988 PB - MDPI CY - Basel ER - TY - GEN A1 - Kepir, Yusuf A1 - Seidlitz, Holger A1 - Ulke-Winter, Lars A1 - Kuke, Felix T1 - Geometric optimization and advanced material integration for enhanced thermal performance of compact cross-flow heat exchangers in high-temperature applications T2 - Proceedings of the 6th International Electronic Conference on Applied Sciences, 9–11 December 2025 N2 - Heat exchangers used in high-temperature environments require lightweight designs with high thermal resistance and efficiency. This study numerically investigates the thermal performance of a multi-channel compact cross-flow heat exchanger, focusing on geometric configurations and material selection. KW - Compact heat exchanger KW - Geometric optimization KW - Thermal performance KW - Turbulence promoters KW - Lightweight design Y1 - 2025 UR - https://sciforum.net/paper/view/27631 PB - MDPI CY - Basel ER - TY - GEN A1 - Hajhariri, Aliasghar A1 - Eberwein, Robert A1 - Camplese, Davide A1 - Scarponi, Giordano Emrys A1 - Cozzani, Valerio A1 - Seidlitz, Holger T1 - Cryogenic storage safety : experimental evaluation of insulation under extreme conditions T2 - Journal of loss prevention in the process industries N2 - Hydrogen is recognized as a keystone of the global energy transition, offering a clean, high-energy-density energy carrier ideal for storage and transportation. Among various storage options, liquid hydrogen (LH2) is especially advantageous for both mobile and stationary applications. However, ensuring the safety and performance of LH2 storage systems under extreme thermal conditions, such as fire exposure, remains an engineering challenge. This study introduces an experimental framework, called the Cryogenic High-Temperature Thermal Vacuum Chamber (CHTTVC), designed to investigate the thermal-hydraulic response of vacuum-insulated cryogenic tanks under fire-like conditions. The apparatus enables evaluation of insulation performance, such as perlite and multilayer insulation (MLI), with a focus on thermal degradation, heat ingress, and vacuum stability. Results indicate that combustible MLIs undergo substantial thermal degradation, leading to heat ingress rates of up to 6.5 kW and the formation of hazardous combustion by-products. In contrast, non-combustible MLIs and bulk insulation materials restrict heat ingress to approximately 3 kW while more effectively preserving vacuum integrity. Combustible MLIs also exhibit pronounced pressure increases in the evacuated section, reaching ∼6 × 104 Pa, nearly six times higher than those observed for non-combustible counterparts. Analysis of effective emissivity further reveals an enhancement in radiative heat transfer, approximately five times, for combustible MLIs following degradation. Additionally, marked thermal stratification develops under both nominal and extreme heat loads, with temperature gradients approaching 10 °C per 100 mm during sustained thermal exposure. KW - Liquefied hydrogen KW - Cryogenic storage tank KW - Multi-layer insulation KW - Thermal super-insulation KW - Liquified hydrogen safety Y1 - 2026 U6 - https://doi.org/10.1016/j.jlp.2026.105961 SN - 0950-4230 VL - 101 SP - 1 EP - 20 PB - Elsevier BV CY - Amsterdam ER - TY - GEN A1 - Popiela, Bartosz A1 - Günzel, Stephan A1 - Mair, Georg W. A1 - Seidlitz, Holger T1 - Modelling of the manufacturing process related residual stresses in type 4 pressure vessels for hydrogen storage T2 - European PhD Hydrogen Conference 2024 (EPHyC2024) N2 - The publication is an extended abstract on the modelling of the manufacturing process related residual stresses in type 4 pressure vessels for hydrogen storage. A 2D analytical model based on the classical laminate theory and a 3D finite element model are introduced. The calculated residual stress state after the filament winding process as well as the stress state in service are presented and discussed. KW - Composite KW - Pressure vessel KW - Residual stresses Y1 - 2024 UR - https://www.researchgate.net/publication/379824070_Modelling_of_the_Manufacturing_Process_Related_Residual_Stresses_in_Type_4_Pressure_Vessels_for_Hydrogen_Storage SP - 445 EP - 450 ER - TY - CHAP A1 - Köhler, Mathias A1 - Seidlitz, Holger ED - Gianaris, Nicholas J. ED - Russell, John D. T1 - Bio-Based Resins T2 - ASM handbook : 21 composites N2 - This article provides a general overview of bio-based resins, first examining biological sources for feedstocks of bio-based resin components, followed by a detailed description of five major resin classes (phenolic, furane, unsaturated polyester, epoxy, and benzoxazine resins) and their bio-based alternatives. It also describes the methods used to synthesize and modify the bio-based resins based on the biological feedstock, manufacturing processes, and properties of neat resins in comparison to fiber-reinforced composites. Then, the current work on novel bio-based vinyl ester, acrylic, and bismaleimide resins is highlighted. The article also reviews the work on the use of renewable resources to produce bio-resins with respect to composite applications, because only the development of bio-based resins leads to the production of sustainable green composites. KW - Bio-based Resins Y1 - 2026 SN - 978-1-62708-489-5 U6 - https://doi.org/10.31399/asm.hb.v21.a0007096 SP - 1 EP - 11 PB - ASM International CY - Materials Park, Ohio ER - TY - GEN A1 - Gebhard, Johannes A1 - Seidlitz, Holger T1 - Demontagegerechte thermoplastische Nietverbindung für das Fahrzeuginterieur T2 - Automobiltechnische Zeitschrift : ATZ N2 - Bei einigen Interieurkomponenten werden Reparaturen durch eine Vielzahl an nichtlösbaren Verbindungselementen erschwert. Zudem fordern ökologische Vorgaben den Übergang zu Kreislaufmodellen. Bei Mercedes-Benz hat man eine Nietlösung erarbeitet, die eine schnelle, kostengünstige De- und Remontage von Bauteilen unter Verwendung wiederverwertbarer Materialien gewährleistet. KW - Thermoplastische Nietverbindung KW - Fahrzeuginterieur KW - Wiederverwertbare Materialien Y1 - 2026 UR - https://link.springer.com/article/10.1007/s35148-025-2330-z U6 - https://doi.org/10.1007/s35148-025-2330-z SN - 0001-2785 VL - 128 IS - 2-3 SP - 16 EP - 23 PB - Springer Professional ER - TY - GEN A1 - Dreyer, Christian A1 - Müller, Vivian C. A1 - Bernaschek, Andreas A1 - Frahm, Mike A1 - Jankowski, Benjamin A1 - Elagroudy, Youssef A1 - Koppusch, Klarissa A1 - Fiedler, Tom A1 - Eckert, Angelika A1 - Tatai, Tiberiu Mihai A1 - Borges, Ralf A1 - Behrendt, Felix A1 - Fricke, Anna A1 - Schreiner, Monika A1 - Seidlitz, Holger ED - Heinemann, Dag ED - Polder, Gerrit T1 - Functional integration of photonic components for (vertical) urban farming T2 - Photonic Technologies in Plant and Agricultural Science III N2 - The project Food4Future (F4F) is a long-term initiative funded by the German government. The decade-long project aims to develop groundbreaking ideas for urban farming, along with the corresponding materials, technologies and processes. It considers various future scenarios such as the collapse of global supply chains (“no trade”) and a severe shortage of arable land (“no land”). Different strategies for cultivating organisms such as crickets, jellyfish, halophytes and algae in an urban environment are being developed. New modular cultivation compartments have been constructed and built which can be used as stand-alone units or in a paternoster (continuous loop) system. An overview is given on the functional integration of SMD-LEDs, ranging from large planar flat units for halophyte cultivation to salt water-resistant UV-LED light sabers for algae cultivation and LEDs integrated directly into transparent composites. KW - Urban farming KW - Photonic components KW - Food4Future (F4F) KW - UV-LED Y1 - 2026 U6 - https://doi.org/10.1117/12.3081069 SN - 277-786X PB - SPIE CY - Bellingham, WA ER - TY - GEN A1 - Gebhard, Johannes A1 - Seidlitz, Holger T1 - Disassembly-optimized thermoplastic rivet connection for vehicle interiors T2 - ATZ worldwide N2 - Repairs to some interior components are made difficult by a large number of non-detachable connecting elements. In addition, environmental regulations are calling for a transition to circular models. Mercedes-Benz has developed a rivet solution that ensures quick, cost-effective disassembly and reassembly of components using recyclable materials. KW - Thermoplastic rivet connection KW - Vehicle Interiors KW - recyclable materials Y1 - 2026 U6 - https://doi.org/10.1007/s38311-025-2167-9 SN - 2192-9076 VL - 128 IS - 2-3 SP - 16 EP - 23 PB - Springer Science and Business Media LLC CY - Wiesbaden ER -