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 -