TY - GEN A1 - Santhanakrishnan Balakrishnan, Venkateswaran A1 - Seidlitz, Holger A1 - Wartig, Kevin A1 - Tsombanis, Nikolas T1 - Influence of processing parameters on the impact behaviour of glass/polyamide-6 composite T2 - Composites Part B: Engineering N2 - This study aims to investigate the low-velocity impact response and post-impact flexural behaviour of glass/polyamide-6 (G/PA-6) composite. G/PA-6 composites with a layup configuration of [02,902]s were prepared via press-forming technique. Composite samples were developed using four different processing conditions, by modifying compression pressure and heating temperature. Local variations of fiber volume and porosity fraction were noticed for samples developed in each processing conditions. On the investigated samples, damages were induced by using 35 joule of drop weight impact to investigate the impact resistance of samples with respect to different processing conditions. The damage behaviour and residual flexural strength was characterized using a micro-CT and three-point bending tests respectively. Furthermore, the influence of porosity fraction on the residual flexural strength were investigated. This paper will provide necessary fundamental knowledge for future selection of processing parameters in order to have enhanced impact performance. KW - A. Polymer-matrix composites (PMCs) KW - A. Thermoplastic resin KW - B. Impact behaviour KW - B. Porosity KW - B. Fracture KW - Press forming technology Y1 - 2019 UR - http://www.sciencedirect.com/science/article/pii/S1359836818318535 U6 - https://doi.org/10.1016/j.compositesb.2018.09.064 SN - 1359-8368 VL - 159 SP - 292 EP - 299 ER - TY - GEN A1 - Santhanakrishnan Balakrishnan, Venkateswaran A1 - Seidlitz, Holger A1 - Weiß, Sabine T1 - Layup Configuration Effect on Notch Residual Strength in Composite Laminates T2 - Materials N2 - The current trend shows an increasing demand for composites due to their high stiffness to weight ratio and the recent progress in manufacturing and cost reduction of composites. To combine high strength and stiffness in a cost-effective way, composites are often joined with steel or aluminum. However, joining of thermoset composite materials is challenging because circular holes are often used to join them with their metal counterparts. These design based circular holes induce high stress concentration around the hole. The purpose of this paper is to focus on layup configuration and its impact on notch stress distribution. To ensure high quality and uniformity, the holes were machined by a 5 kW continuous wave (cw) CO2 laser. The stress distribution was evaluated and compared by using finite element analysis and Lekhnitskii’s equations. For further understanding, the notch strength of the laminates was compared and strain distributions were analyzed using the digital image correlation technique. KW - composite KW - notch stress KW - digital image correlation KW - ekhnitskii’s equation Y1 - 2018 U6 - https://doi.org/10.3390/ma11020308 SN - 1996-1944 VL - 11 IS - 2 ER - TY - CHAP A1 - Fritzsche, Sebastian A1 - Kloshek, Alexander A1 - Dietz, Eric A1 - Michailov, Vesselin A1 - Seidlitz, Holger A1 - Ossenbrink, Ralf T1 - SLM gefertigte Verbindungsknoten für Leichtbaurahmenelemente T2 - DVS Congress 2018 : Große Schweißtechnische Tagung, DVS-Studentenkongress, Vorträge der Veranstaltungen in Friedrichshafen am 17. und 18. September 2018 N2 - SLM gefertigte Verbindungsknoten für Leichtbaurahmenelemente KW - Selective Laser Melting KW - SLM KW - Leichtbau KW - 1.4404 KW - Topologieoptimierung KW - Schubfeld Y1 - 2018 SN - 978-3-96144-036-8 IS - 264 EP - 258 PB - DVS Media GmbH CY - Düsseldorf ER - TY - GEN A1 - Yellur, Manoja Rao A1 - Seidlitz, Holger A1 - Kuke, Felix A1 - Wartig, Kevin A1 - Tsombanis, Nikolas T1 - A low velocity impact study on press formed thermoplastic honeycomb sandwich panels T2 - Composite Structures N2 - At present plywood structures are used in the loading area of utility structures. Low velocity impact studies on these structures showed cracks on its lower surface. Hence, in the current study low-velocity impact of a lighter honeycomb sandwich structure is investigated to satisfy the needs of the utility vehicle segment. To meet this objective, facing sheets are manufactured using the polypropylene matrix and glass fibers. Polypropylene honeycombs are used in the study. Depending on the experimental boundary conditions, a cross-ply laminate set up is used for the facing sheets. An impact energy of 100 J is chosen in the study. This energy caused visible failure on the plywood sample. Hence a lighter sandwich construction which can resist 100 J impact is implemented in this study. Influence of top and bottom facing sheet thicknesses on the amount of damage inflicted on its surfaces are studied. Experimental histories of absorbed energy and contact force are recorded. A finite element analysis is performed using LS-DYNA and numerical results are compared with the experimental responses. A honeycomb sandwich panel [0/90/90/0/Core/0/90/90/0] meeting the objective of the study is seen as an optimum replacement for the existing plywood structures. KW - Low-velocity impact KW - Sandwich panel KW - Honeycomb core KW - Finite element analysis (FEA) Y1 - 2019 UR - http://www.sciencedirect.com/science/article/pii/S0263822318334743 U6 - https://doi.org/10.1016/j.compstruct.2019.111061 SN - 0263-8223 VL - 225 SP - 111061 ER - TY - GEN A1 - Santhanakrishnan Balakrishnan, Venkateswaran A1 - Obrosov, Aleksei A1 - Kuke, Felix A1 - Seidlitz, Holger A1 - Weiß, Sabine T1 - Influence of metal surface preparation on the flexural strength and impact damage behaviour of thermoplastic FRP reinforced metal laminate made by press forming T2 - Composites Part B: Engineering N2 - In this paper the relationship between surface energy and flexural strength of metal laminate made by reinforcing glass fibre reinforced polymer on steel surfaces was investigated. Sand blasting was performed on 22MnB5 steel surface. This steel was stacked together with layers of unidirectional glass/polyamide-6 prepreg, followed by pressing in a hot press. Influenced parameters are pressure, temperature and time. 3D profilometer analysis was used to investigate the roughness profile on the surface of the steel generated by the sand blasting. The surface energy of the steel surface was calculated from a set of contact angles measured by three different liquids. To identify the optimal surface treatment, the variation of surface energy, flexural strength and roughness of the steel surface was determined as function of the surface treatment. Surface roughness (Ra of 1.08 μm), results indicate that increasing surface roughness leads to improvement in flexural modulus. The increase further leads to decrease in flexural modulus. In addition, the influence of surface energy and flexural strength on the impact damage behaviour was investigated too. The results showed that the sample with highest flexural modulus had the lowest impact-induced damage area. KW - Fiber reinforced plastic (FRP) KW - FRP reinforced metal composite KW - Sand blasting surface treatment KW - Surface energy KW - Contact angle Y1 - 2019 UR - https://www.sciencedirect.com/science/article/pii/S135983681930318X U6 - https://doi.org/10.1016/j.compositesb.2019.05.094 SN - 1359-8368 VL - 173 ER - TY - GEN A1 - Santhanakrishnan Balakrishnan, Venkateswaran A1 - Hart-Rawung, Thawin A1 - Buhl, Johannes A1 - Seidlitz, Holger A1 - Bambach, Markus T1 - Impact and damage behaviour of FRP-metal hybrid laminates made by the reinforcement of glass fibers on 22MnB5 metal surface T2 - Composites Science and Technology Y1 - 2020 U6 - https://doi.org/10.1016/j.compscitech.2019.107949 SN - 1879-1050 SN - 0266-3538 VL - Vol. 187 ER - TY - GEN A1 - Rösch, Janina J. A1 - Seidlitz, Holger A1 - Pfeifer, Robin A1 - Burlefinger, Hubert A1 - Maurer, Thomas T1 - Preform joints in embroidered fabrics – influence on the mechanical properties T2 - Advanced Composite Materials N2 - Preforms with large complex geometry, for example, body parts for the automotive industry, are consisted into multiple elements – so-called sub-preforms. Hereby the sub-preforms can be adjusted to different local load cases but joining of these sub-preforms also raises challenges. The preform joints are decisive to the mechanical properties of the final component. The state-of-the-art joint, a single lap, results in a variation of wall thickness with local redirection of fibre orientation. In this paper, the influence of alternative joints of embroidered fabrics is analysed regarding the resulting mechanical properties of the part. The built test specimen contains different preform joints with different process-relevant parameters. Such as gaps between the sub-preforms, to analyse the influence on the mechanical performance. To reveal the various defects like voids, air pockets and to validate the fibre orientation, computer tomography (CT) investigation was performed on the built plates. In addition, the influence in mechanical properties was also analysed. The overlapping is analysed with tensile strength test according to DIN EN ISO 527-4. Y1 - 2020 UR - https://www.tandfonline.com/doi/abs/10.1080/09243046.2020.1744345 SP - 1 EP - 16 ER - TY - GEN A1 - Shapovalov, Oleg A1 - Seidlitz, Holger A1 - Ost, Lucas A1 - Doynov, Nikolay A1 - Kuke, Felix A1 - Ambrosio, Marcello A1 - Michailov, Vesselin T1 - Substitution von metallischen Schubfeldern im Fahrzeugbau durch fügetechnische Integration von FKV-Schalen T2 - DVS Congress 2022, Große Schweißtechnische Tagung, DVS Campus ; Kurzfassungen der Vorträge der Veranstaltung in Koblenz vom 19. bis 21. September 2022 ; (Langfassungen der Beiträge auf USB-Karte) N2 - 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 Stählen bietet, im Vergleich zu anderen Verfahren, neben einer einseitigen Zugänglichkeit, 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 Vorwärmen von Organoblechen mittels Infrarotstrahlung entwickelt. Die Eignung der CMT-Pin-Technologie wurde sowohl für das Fügen von karbon- als auch glasfaserverstärktem PA6 betrachtet. Als Bewertungskriterien wurden das Schweißgut sowie der Faser- und Matrixerhalt in Abhängigkeit der Schweißparameter untersucht. Das entwickelte Verfahren wurde mit herkömmlichen Fügemethoden bzgl. der in Kopf- und Scherzugversuchen ermittelten Festigkeiten verglichen. Zur Bestimmung der Beständigkeit der Verbindungen gegen unterschiedliche Witterungsbedingungen wurden Salzsprühnebel- und Wechselkorrosionstests durchgeführt. Mit dem Fügen von Hutprofilen wurde die Anwendung der entwickelte CMT-Pin-Technik am Tunnel sowie den Längs- und Querträgern der Bodenstruktur eines Kraftfahrzeugs demonstriert. Y1 - 2022 UR - https://www.dvs-ev.de/call4papers/abstract.cfm?vid=115&pid=7586 SN - 978-3-96144-189-1 SP - 385 EP - 393 PB - DVS Media GmbH CY - Düsseldorf ER - TY - GEN A1 - Hannan, Azmin Nasrin A1 - Seidlitz, Holger A1 - Müller, Marco A1 - Krenz, Jonas T1 - Investigations of technical challenges in compounding of recycled carbon fibers T2 - Zarzadzanie Przedsiebiorstwem. Enterprise Management N2 - 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. KW - CFRP KW - rCF KW - recycling KW - circular economy KW - compounding KW - carbon fibers Y1 - 2023 UR - https://zp.ptzp.org.pl/ZPEM_26_2-2023.html U6 - https://doi.org/10.25961/ent.manag.26.01.03 SN - 1643-4773 VL - 26 IS - 2 SP - 7 EP - 12 ER - TY - CHAP A1 - Seidlitz, Holger A1 - Ulke-Winter, Lars A1 - Kuke, Felix A1 - Ost, Lucas ED - Kumar, Sanjeev T1 - Material and Load Path Appropriate Joining Techniques for FRP/Metal Hybrid Structures T2 - Welding - Materials, Fabrication Processes, and Industry 5.0 N2 - 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. KW - fiber-reinforced plastics KW - thermomechanical flow drill joining KW - cold metal transfer pin welding KW - load path KW - fiber orientation Y1 - 2023 UR - https://www.intechopen.com/books/1002588 SN - 978-1-83769-870-7 SN - 978-1-83769-872-1 U6 - https://doi.org/10.5772/intechopen.1002239 PB - IntechOpen CY - London ET - 1. Auflage ER - TY - GEN A1 - Hannan, Azmin Nasrin A1 - Seidlitz, Holger A1 - Hartung, David A1 - Kuke, Felix A1 - Ambrosio, Marcello A1 - Müller, Marco T1 - Sustainability and Circular Economy in Carbon Fiber-Reinforced Plastics T2 - Materials Circular Economy N2 - 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. KW - Sustainability KW - Circular Economy KW - Carbon Fiber-Reinforced Plastics Y1 - 2024 U6 - https://doi.org/10.1007/s42824-024-00111-2 SN - 2524-8146 VL - 6 IS - 1 PB - Springer Science and Business Media LLC ER - TY - GEN A1 - Erekath, Swathi A1 - Seidlitz, Holger A1 - Schreiner, Monika A1 - Dreyer, Christian T1 - Food for future: Exploring cutting-edge technology and practices in vertical farm T2 - Sustainable Cities and Society N2 - 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. KW - Transportation KW - Renewable Energy, Sustainability and the Environment KW - Civil and Structural Engineering KW - Geography, Planning and Development Y1 - 2024 U6 - https://doi.org/10.1016/j.scs.2024.105357 SN - 2210-6707 VL - 106 ER - TY - GEN A1 - Recupido, Federica A1 - Lama, Giuseppe Cesare A1 - Steffen, Sebastian A1 - Dreyer, Christian A1 - Seidlitz, Holger A1 - Russo, Vincenzo A1 - Lavorgna, Marino A1 - De Luca Bossa, Ferdinando A1 - Silvano, Selena A1 - Boggioni, Laura A1 - Verdolotti, Letizia T1 - Efficient recycling pathway of bio-based composite polyurethane foams via sustainable diamine T2 - Ecotoxicology and Environmental Safety N2 - 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. KW - Health, Toxicology and Mutagenesis KW - Public Health, Environmental and Occupational Health KW - Pollution KW - General Medicine Y1 - 2024 U6 - https://doi.org/10.1016/j.ecoenv.2023.115758 SN - 0147-6513 VL - 269 ER - TY - GEN A1 - Błędzki, Andrzej A1 - Seidlitz, Holger A1 - Urbaniak, Magdalena A1 - Köhler, Mathias A1 - Adamcio, Andrzej A1 - Sobczyk, Marcin A1 - Demski, Szymon A1 - Boczkowska, Anna T1 - Reusing and recycling of composite wind turbine blades. A review of current practices and prospects. Part 1. Academic research T2 - Przemysł chemiczny N2 - 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. KW - General Chemical Engineering KW - General Chemistry KW - polymer composites KW - wind turbine blades KW - global recycling projects KW - practical recovery and reuse KW - recycled carbon fibers Y1 - 2024 U6 - https://doi.org/10.15199/62.2024.2.2 SN - 0033-2496 VL - 103 IS - 2 SP - 225 EP - 233 ER - TY - GEN A1 - Błędzki, Andrzej A1 - Seidlitz, Holger A1 - Urbaniak, Magdalena A1 - Köhler, Mathias A1 - Adamcio, Andrzej A1 - Sobczyk, Marcin A1 - Demski, Szymon A1 - Boczkowska, Anna T1 - Reusing and recycling of composite wind turbine blades. A review of current practices and prospects. Part 2. Industrial activities T2 - Przemysł chemiczny N2 - 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 KW - General Chemical Engineering KW - General Chemistry KW - polymer composites KW - wind turbine blades KW - global recycling projects KW - practical recovery and reuse KW - recycled carbon fibers Y1 - 2024 U6 - https://doi.org/10.15199/62.2024.2.3 SN - 0033-2496 VL - 103 IS - 2 SP - 234 EP - 240 ER -