@misc{ShapovalovSeidlitzOstetal., author = {Shapovalov, Oleg and Seidlitz, Holger and Ost, Lucas and Doynov, Nikolay and Kuke, Felix and Ambrosio, Marcello and Michailov, Vesselin}, title = {Substitution von metallischen Schubfeldern im Fahrzeugbau durch f{\"u}getechnische Integration von FKV-Schalen}, series = {DVS Congress 2022, Große Schweißtechnische Tagung, DVS Campus ; Kurzfassungen der Vortr{\"a}ge der Veranstaltung in Koblenz vom 19. bis 21. September 2022 ; (Langfassungen der Beitr{\"a}ge auf USB-Karte)}, journal = {DVS Congress 2022, Große Schweißtechnische Tagung, DVS Campus ; Kurzfassungen der Vortr{\"a}ge der Veranstaltung in Koblenz vom 19. bis 21. September 2022 ; (Langfassungen der Beitr{\"a}ge auf USB-Karte)}, publisher = {DVS Media GmbH}, address = {D{\"u}sseldorf}, isbn = {978-3-96144-189-1}, pages = {385 -- 393}, abstract = {Durch den strukturellen Einsatz von Faser-Kunststoff-Verbunden (FKV) lassen sich hochwertige gewichtsoptimierte Karosserien in Mischbauweise umsetzen. Die untersuchte CMT-Pin-Schweißtechnik zur Verbindung von thermoplastischen Organoblechen mit St{\"a}hlen bietet, im Vergleich zu anderen Verfahren, neben einer einseitigen Zug{\"a}nglichkeit, ein hohes Leichtbaupotenzial. Das Vorhaben wurde auf eine werkstoff-, prozess- und konstruktionsgerechte Umsetzung des Verfahrens ausgerichtet. Auf Basis experimenteller und numerischer Untersuchungen wurde eine Methode zum Vorw{\"a}rmen von Organoblechen mittels Infrarotstrahlung entwickelt. Die Eignung der CMT-Pin-Technologie wurde sowohl f{\"u}r das F{\"u}gen von karbon- als auch glasfaserverst{\"a}rktem PA6 betrachtet. Als Bewertungskriterien wurden das Schweißgut sowie der Faser- und Matrixerhalt in Abh{\"a}ngigkeit der Schweißparameter untersucht. Das entwickelte Verfahren wurde mit herk{\"o}mmlichen F{\"u}gemethoden bzgl. der in Kopf- und Scherzugversuchen ermittelten Festigkeiten verglichen. Zur Bestimmung der Best{\"a}ndigkeit der Verbindungen gegen unterschiedliche Witterungsbedingungen wurden Salzspr{\"u}hnebel- und Wechselkorrosionstests durchgef{\"u}hrt. Mit dem F{\"u}gen von Hutprofilen wurde die Anwendung der entwickelte CMT-Pin-Technik am Tunnel sowie den L{\"a}ngs- und Quertr{\"a}gern der Bodenstruktur eines Kraftfahrzeugs demonstriert.}, language = {de} } @misc{HannanSeidlitzMuelleretal., author = {Hannan, Azmin Nasrin and Seidlitz, Holger and M{\"u}ller, Marco and Krenz, Jonas}, title = {Investigations of technical challenges in compounding of recycled carbon fibers}, series = {Zarzadzanie Przedsiebiorstwem. Enterprise Management}, volume = {26}, journal = {Zarzadzanie Przedsiebiorstwem. Enterprise Management}, number = {2}, issn = {1643-4773}, doi = {10.25961/ent.manag.26.01.03}, pages = {7 -- 12}, abstract = {Carbon fiber reinforced plastics (CFRP) owing to its excellent properties have found its extensive application in various fields ranging from medical to automobile and aerospace industries. This has thereby led to ever-increasing demand of carbon fiber production and as well as resulting in tonnes of carbon fiber wastes in the landfills [5]. Due to the high positive impacts of using carbon fibers, the energy intensive and cost intensive production of virgin fibers and the growing landfills are often overlooked. Hence, the need for recycling and repurposing of carbon fiber wastes have gained the significance at present day. Although various recycling technologies have been developed yet, various challenges are faced with processing of recycled carbon fibers (rCF). Besides, the desired application specific properties are not compromised for high cost and high-energy requirement. Therefore, an overall development of processing rCF is sought from not only a sustainability point but also an economic point. Various efficient recycling technologies are currently operating. The challenges arises in commercializing the recycled fibers after the recycling process. The recycled fibers often require various post-processing of fibers and undergoes fiber degradation. This induces a skeptical mindset for the buyers to introduce the recycled fibers in the material ecosystem. This paper currently discusses the processing challenges of long rCF in a compounding plant. To form a closed loop, the recycled fibers are obtained from the novel thermocatalytic degassing process from the CFRP recycling pioneers in Germany, Global EnerTec AG, Guben. This plant in Guben not only recycles carbon fibers from automotive CFRP wastes but also repurposes the epoxy matrices into secondary energy sources. This paper focuses in investigating the processing of rCF obtained from a 100\% recycling technology. The aim is to investigate the possible technical challenges so that the rCF can be repurposed to new product manufacturing. Thereby, addressing the concerns with the development of closed loop circular economy in recycling CFRP wastes.}, language = {en} } @incollection{SeidlitzUlkeWinterKukeetal., author = {Seidlitz, Holger and Ulke-Winter, Lars and Kuke, Felix and Ost, Lucas}, title = {Material and Load Path Appropriate Joining Techniques for FRP/Metal Hybrid Structures}, series = {Welding - Materials, Fabrication Processes, and Industry 5.0}, booktitle = {Welding - Materials, Fabrication Processes, and Industry 5.0}, editor = {Kumar, Sanjeev}, edition = {1. Auflage}, publisher = {IntechOpen}, address = {London}, isbn = {978-1-83769-870-7}, doi = {10.5772/intechopen.1002239}, abstract = {Fiber-reinforced plastics (FRP) offer great lightweight construction potential. However, the anisotropic high-performance materials can only be fully utilized through the development of material-specific joining processes. A literature study shows that conventional methods such as screwing, riveting and bolting are unsuitable, since the load-bearing fibers are severed in the joining region. This leads to high-stress concentrations. To reduce these, a method is presented in which through holes are created in thermoplastic FRP by reorienting the fibers in this area around the point of disruption in accordance with the load path. For this purpose, the polymer matrix is softened locally by applying heat and penetrated with a needle or mandrel. Based on this, a technology for material-specific joining of FRP and metals has been developed in the form of thermomechanical flow drill joining. In this process, a mandrel forms a bush from the metal component and deflects the fibers of the locally softened organic sheet to suit the material. Cold metal transfer (CMT) pin welding is presented as another fully automatable joining process. In this method, the softened plastic component is penetrated with the welding wire, displacing the fibers in the joining area and realigning them to suit the load path.}, language = {en} } @misc{HannanSeidlitzHartungetal., author = {Hannan, Azmin Nasrin and Seidlitz, Holger and Hartung, David and Kuke, Felix and Ambrosio, Marcello and M{\"u}ller, Marco}, title = {Sustainability and Circular Economy in Carbon Fiber-Reinforced Plastics}, series = {Materials Circular Economy}, volume = {6}, journal = {Materials Circular Economy}, number = {1}, publisher = {Springer Science and Business Media LLC}, issn = {2524-8146}, doi = {10.1007/s42824-024-00111-2}, pages = {11}, abstract = {Carbon fiber-reinforced plastic (CFRP) components are known for their exceptional resilience and ultra-lightweight nature, making them the preferred choice for applications requiring high mechanical loads with minimal weight. However, the intricate and anisotropic structure of CFRP components poses challenges, resulting in expensive repairs and testing. This complexity also leads to increased waste generation. Yet, innovative recycling processes offer a solution by reintegrating carbon components into a closed material cycle, promoting sustainability and circular economy principles. This work focuses on recycled CFs (rCFs) obtained through a continuous recycling method for CFRP primary recyclate from composite pressure vessel. Furthermore, re-purposing of the separated matrix material for secondary energy sources makes the process, a 100\% recycling route. This closed-loop approach addresses conventional pyrolysis challenges and contributes to more efficient utilization of CFRP waste components. rCF and recycled polyethylene terephthalate (rPET) polymers were compounded through an extrusion process. Test specimens were then fabricated according to standard test norms to evaluate the resulting tensile and bending properties. The tensile and flexural modulus of the rCF-rPET obtained are 6.80 and 4.99 GPa, respectively. The need for enhancing the quality of rCF is apparent. Suggestive and potential implications and the marketability of rCF-rPET compounds are also discussed.}, language = {en} } @misc{ErekathSeidlitzSchreineretal., author = {Erekath, Swathi and Seidlitz, Holger and Schreiner, Monika and Dreyer, Christian}, title = {Food for future: Exploring cutting-edge technology and practices in vertical farm}, series = {Sustainable Cities and Society}, volume = {106}, journal = {Sustainable Cities and Society}, issn = {2210-6707}, doi = {10.1016/j.scs.2024.105357}, abstract = {With the growing urbanized population, vertical farming becomes indispensable in eradicating hunger and ensuring food security for the future. Food security has become a major challenge for the future owing to the scarcity of land, rising global population, urbanization, and polluted soil and water resources. In this scenario, vertical farming as an innovative food production technology caters increased productivity with limited resources and improved carbon footprint. The review begins with a brief introduction to the concept of vertical farming, its opportunities and implications on the economy, environment, and society as a whole, following with an in-depth qualitative analysis of the cutting-edge innovations/technologies are presented in detail. Contrary to the numerous research focusing on mere analysis of economic viability and statistical analysis, the aim is to introduce real cutting-edge technologies that address the challenges of vertical farms such as lack of technical skills or energy requirements. The recent advances of vertical farms includes construction of outer vertical structure and growing shelves using light weight and transparent polymer composites, engineered and tunable LEDs lightings, 3-D printed and recyclable growing substrates, AI-integrated IoTs for environment control, harvesting materials for renewable energy storage etc. Such material innovations with inclusion of AI and robotics transform automated vertical farming into 'state of the art' agricultural technology. Production shelf fabricated using UV cured GBOV-glass fiber composite with 60\% transparency can overcome the material weight limitation, corrosion, light obstructions etc. associated with the conventional steel shelves. Replacing non-renewable fossil fuels using renewable energy harvested by carbon dots, fluorescent materials, and perovskite solar cells is recommended to minimize the high capital investments associated with energy as well as to reduce the environmental impact. Smart materials such as phase change materials and thermoresponsive windows control the amount of energy expended whereas smart substrate promotes resource management. Application of the newest technology AI in vertical farming facilitates precise control of environment, early pest detection, automation of farming processes, data-driven decision making and precision agriculture. In short, vertical farms utilizing modern innovations of science and technology caters enhanced productivity, improved quality, reduced cost, resource management and sustainability. Hence, automated and sustainable vertical farms promoting global food security and circularity have the potential to transform into burgeoning technology of future.}, language = {en} } @misc{RecupidoLamaSteffenetal., author = {Recupido, Federica and Lama, Giuseppe Cesare and Steffen, Sebastian and Dreyer, Christian and Seidlitz, Holger and Russo, Vincenzo and Lavorgna, Marino and De Luca Bossa, Ferdinando and Silvano, Selena and Boggioni, Laura and Verdolotti, Letizia}, title = {Efficient recycling pathway of bio-based composite polyurethane foams via sustainable diamine}, series = {Ecotoxicology and Environmental Safety}, volume = {269}, journal = {Ecotoxicology and Environmental Safety}, issn = {0147-6513}, doi = {10.1016/j.ecoenv.2023.115758}, abstract = {Aminolysis is widely recognized as a valuable chemical route for depolymerizing polymeric materials containing ester, amide, or urethane functional groups, including polyurethane foams. Bio-based polyurethane foams, pristine and reinforced with 40 wt\% of sustainable fillers, were depolymerized in the presence of bio-derived butane-1,4-diamine, BDA. A process comparison was made using fossil-derived ethane-1,2-diamine, EDA, by varying amine/polyurethane ratio (F/A, 1:1 and 1:0.6). The obtained depolymerized systems were analyzed by FTIR and NMR characterizations to understand the effect of both diamines on the degradation pathway. The use of bio-based BDA seemed to be more effective with respect to conventional EDA, owing to its stronger basicity (and thus higher nucleophilicity), corresponding to faster depolymerization rates. BDA-based depolymerized systems were then employed to prepare second-generation bio-based composite polyurethane foams by partial replacement of isocyanate components (20 wt\%). The morphological, mechanical, and thermal conductivity properties of the second-generation polyurethane foams were evaluated. The best performances (σ10 \%=71 ± 9 kPa, λ = 0.042 ± 0.015 W∙ m-1 ∙K-1) were attained by employing the lowest F/A ratio (1:0.6); this demonstrates their potential application in different sectors such as packaging or construction, fulfilling the paradigm of the circular economy.}, language = {en} } @misc{BłędzkiSeidlitzUrbaniaketal., author = {Błędzki, Andrzej and Seidlitz, Holger and Urbaniak, Magdalena and K{\"o}hler, Mathias and Adamcio, Andrzej and Sobczyk, Marcin and Demski, Szymon and Boczkowska, Anna}, title = {Reusing and recycling of composite wind turbine blades. A review of current practices and prospects. Part 1. Academic research}, series = {Przemysł chemiczny}, volume = {103}, journal = {Przemysł chemiczny}, number = {2}, issn = {0033-2496}, doi = {10.15199/62.2024.2.2}, pages = {225 -- 233}, abstract = {A review, with 34 refs., of new materials for manufacturing the turbine blades, processes for monitoring maintenance and structural health of the blades as well as chem., thermal and mech. blade recycling technologies.}, language = {en} } @misc{BłędzkiSeidlitzUrbaniaketal., author = {Błędzki, Andrzej and Seidlitz, Holger and Urbaniak, Magdalena and K{\"o}hler, Mathias and Adamcio, Andrzej and Sobczyk, Marcin and Demski, Szymon and Boczkowska, Anna}, title = {Reusing and recycling of composite wind turbine blades. A review of current practices and prospects. Part 2. Industrial activities}, series = {Przemysł chemiczny}, volume = {103}, journal = {Przemysł chemiczny}, number = {2}, issn = {0033-2496}, doi = {10.15199/62.2024.2.3}, pages = {234 -- 240}, abstract = {A review, with 33 refs., of projects currently implemented and planned by large consortia in the area of recovering variety of composite materials for their reuse}, language = {en} } @misc{BłędzkiSeidlitzUrbaniaketal., author = {Błędzki, Andrzej and Seidlitz, Holger and Urbaniak, Magdalena and K{\"o}hler, Mathias and Adamcio, Andrzej and Sobczyk, Marcin and Demski, Szymon and Boczkowska, Anna}, title = {Reusing and recycling of composite wind turbine blades. A review of current practices and prospects. Part 3. Various proposals offered by small and middle companies}, series = {Przemysł chemiczny}, volume = {103}, journal = {Przemysł chemiczny}, number = {2}, issn = {0033-2496}, doi = {10.15199/62.2024.2.4}, pages = {241 -- 250}, abstract = {A review, with 32 refs., of various new proposals for recycling and reusing of wind turbine blades by small companies (including the Polish Anmet company). New projects on shredding blades as well as on architecture objects, road construction, geotechn. blocks, floating platforms and observation towers were presented. Prodn. of composite chipboard panels and recovery of carbon fibers by waste pyrolysis were also included.}, language = {en} } @misc{MiahKloshekOssenbrinketal., author = {Miah, Kamal Uddin Mohammad and Kloshek, Alexander and Ossenbrink, Ralf and Seidlitz, Holger}, title = {Selective Laser Melting of Pure Copper (Cu-ETP)}, series = {4th Symposium on Materials and Additive Manufacturing, Additive 2024, 22. - 24. Mai 2024, Book of Abstracts}, journal = {4th Symposium on Materials and Additive Manufacturing, Additive 2024, 22. - 24. Mai 2024, Book of Abstracts}, publisher = {Deutsche Gesellschaft f{\"u}r Materialkunde (DGM) e.V.}, address = {Bremen, Berlin}, isbn = {978-3-88355-440-2}, pages = {19}, abstract = {The main objective of this study is to address the difficulties related to the production of highly dense parts utilizing pure Cu-ETP powder. In order to achieve this goal, the SLM machine was modified by replacing the regular infrared laser with a laser operating in the range of 530 to 534 nm. Following this modification, a detailed experiment was conducted to determine the most effective procedural parameters for producing solid components and gyroid structures of Cu-ETP. The study determined thtat in order to produce a part density of 99.6 ± 0.2\%, the following parameters are required: a laser power of 130 ± 10 W, a scanning speed of 350 mm/s, and a layer thickness of 25 µm. The microscopic analysis on the SLM-manufactured components showed a consistent grain structure across the build parts. Furthermore, it was discovered that exceeding the predetermined laser power and scanning speed parameters led to lower density of the parts. Conversely, decreasing the laser power and scanning speed below these thresholds was determined to be economically disadvantageous.}, language = {en} } @misc{KehmWasilewskiMiahetal., author = {Kehm, Christian and Wasilewski, Eric and Miah, Kamal Uddin Mohammad and Ossenbrink, Ralf and Seidlitz, Holger}, title = {Effects of extended shielding gas coverage on component contour accuracy in Wire Arc Additive Manufacturing}, series = {4th Symposium on Materials and Additive Manufacturing, Additive 2024, 22. - 24. Mai 2024, Book of Abstracts}, journal = {4th Symposium on Materials and Additive Manufacturing, Additive 2024, 22. - 24. Mai 2024, Book of Abstracts}, publisher = {Deutsche Gesellschaft f{\"u}r Materialkunde (DGM) e.V.}, address = {Bremen, Berlin}, isbn = {978-3-88355-440-2}, pages = {29}, abstract = {Producing near-net-shape components with Wire Arc Additive Manufacturing (WAAM) is a challenging task. Compared to laser-based additive manufacturing technologies, WAAM is characterized by a lower contour accuracy with higher surface roughness and more uneven surface profiles. Therefore, the WAAM requires a high degree of post-processing (machining) which reduces economic efficiency and increases material consumption. Therefore, topics such as process optimization with regard to the component contour are increasingly in the focus of research. This study presents the application of an extended shielding gas coverage in the WAAM process of steel to improve part contour accuracy. A specially adapted shielding gas coverage was manufactured with laser powder bed fusion and following used to study the influence on the resulting component contour and properties in comparison to standard shielding gas nozzles. The investigations include the analysis of temperature profiles, shape deviations, hardness and porosity in the component. In addition, process parameters such as gas flow rate and nozzle geometry were varied in order to evaluate their influence on the accuracy of the component contour. The extended shielding gas coverage reduces the average deviation from the target contour significantly by a degree of 49,44\%. In addition, the maximum of the occurring deviation height could be decreased by 42,39\%. The results show an improvement in the dimensional accuracy of the contour and the surface quality, resulting in higher reproducibility and less post-processing effort.}, language = {en} } @misc{NikitinTurabovErmilovaetal., author = {Nikitin, Alexander and Turabov, Dashqin and Ermilova, Evgeniia and Evdokimov, Anton and Ossenbrink, Ralf and Seidlitz, Holger}, title = {Using dynamic resistance to predict electrode surface degradation in resistance spot welding of 5182 aluminum alloy}, series = {Welding in the World}, volume = {69}, journal = {Welding in the World}, doi = {10.1007/s40194-024-01872-9}, pages = {449 -- 458}, abstract = {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.}, language = {en} }