@inproceedings{KukeKloshekMichailov, author = {Kuke, Felix and Kloshek, Alexander and Michailov, Vesselin}, title = {Untersuchung des Einflusses von rohrf{\"o}rmigen Stahlelektroden auf das Prozessverhalten und den Werkstoff{\"u}bergang beim MSG-Schweißen}, series = {DVS Congress, September 2015, N{\"u}rnberg}, booktitle = {DVS Congress, September 2015, N{\"u}rnberg}, publisher = {DVS Media GmbH}, address = {D{\"u}sseldorf}, isbn = {978-3-945023-46-4}, pages = {615 -- 620}, language = {de} } @book{MichailovDoynovKuke, author = {Michailov, Vesselin and Doynov, Nikolay and Kuke, Felix}, title = {Anwendungsnahe Simulation des thermischen Richtens : Forschungsvorhaben P 1008/IGF-Nr. 17970 BR}, publisher = {Verlag und Vertriebsgesellschaft mbH}, address = {D{\"u}sseldorf}, isbn = {978-3-946885-03-0}, pages = {XV, 122}, language = {de} } @inproceedings{DoynovKukeMichailov, author = {Doynov, Nikolay and Kuke, Felix and Michailov, Vesselin}, title = {Thermal straightening simulation of welded structures}, series = {Proceedings, METEC \& 2nd ESTAD 2015, European Steel Technology and Application Days, D{\"u}sseldorf, Germany, CCD Congress Center D{\"u}sseldorf, 15 - 19 June 2015}, booktitle = {Proceedings, METEC \& 2nd ESTAD 2015, European Steel Technology and Application Days, D{\"u}sseldorf, Germany, CCD Congress Center D{\"u}sseldorf, 15 - 19 June 2015}, publisher = {TEMA Technologie Marketing AG}, address = {Aachen}, isbn = {978-3-00-049542-7}, pages = {P 709, 1 -- 6}, language = {en} } @misc{SanthanakrishnanBalakrishnanObrosovKukeetal., author = {Santhanakrishnan Balakrishnan, Venkateswaran and Obrosov, Aleksei and Kuke, Felix and Seidlitz, Holger and Weiß, Sabine}, title = {Influence of metal surface preparation on the flexural strength and impact damage behaviour of thermoplastic FRP reinforced metal laminate made by press forming}, series = {Composites Part B: Engineering}, volume = {173}, journal = {Composites Part B: Engineering}, issn = {1359-8368}, doi = {10.1016/j.compositesb.2019.05.094}, abstract = {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.}, language = {en} } @misc{ShapovalovOstKukeetal., author = {Shapovalov, Oleg and Ost, Lucas and Kuke, Felix and Doynov, Nikolay and Ambrosio, Marcello and Seidlitz, Holger and Michailov, Vesselin}, title = {Entwicklung und Analyse einer F{\"u}gestrategie f{\"u}r FKV/Metall-Mischverbindungen auf Basis der CMT-Pinschweißtechnik}, series = {Joining Plastics}, volume = {17}, journal = {Joining Plastics}, number = {1}, issn = {1864-3450}, pages = {28 -- 35}, abstract = {Dieser Beitrag stellt eine Entwicklung, Anpassung und Untersuchung der neuartigen Pinschweißtechnik zur Verbindung thermoplastischer Faserkunststoffverbunde mit metallischen F{\"u}gepartnern dar. Die untersuchte F{\"u}getechnik bietet, im Vergleich zu anderen Verfahren, neben einer einseitigen Zug{\"a}nglichkeit, ein hohes Leichtbaupotenzial. An Multimaterial-Einzelpinverbindungen wurden die CMT-Pinschweißbarkeit charakterisiert und unterschiedliche F{\"u}gestrategien erprobt und ausgewertet. Als Bewertungskriterien wurden das Schweißgut sowie der Faser- und Matrixerhalt in Abh{\"a}ngigkeit 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 F{\"u}gezone analysiert. Der F{\"u}geprozess wurde an Funktionsmustern und diese wiederum in 3-Punkt-Biegeversuchen validiert sowie mit dem Kleben verglichen.}, language = {de} } @misc{SeidlitzMichailovOstetal., author = {Seidlitz, Holger and Michailov, Vesselin and Ost, Lucas and Kuke, Felix and Ambrosio, Marcello and Shapovalov, Oleg and Doynov, Nikolay}, title = {Simulation of Composites' Heating}, series = {Kunststoffe international}, volume = {113}, journal = {Kunststoffe international}, number = {4}, issn = {1862-4243}, pages = {60 -- 64}, abstract = {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.}, 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{YellurSeidlitzKukeetal., author = {Yellur, Manoja Rao and Seidlitz, Holger and Kuke, Felix and Wartig, Kevin and Tsombanis, Nikolas}, title = {A low velocity impact study on press formed thermoplastic honeycomb sandwich panels}, series = {Composite Structures}, volume = {225}, journal = {Composite Structures}, issn = {0263-8223}, doi = {10.1016/j.compstruct.2019.111061}, pages = {111061}, abstract = {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.}, language = {en} } @inproceedings{SeidlitzKukeTsombanis, author = {Seidlitz, Holger and Kuke, Felix and Tsombanis, Nikolas}, title = {Advanced joining technology for the production of highly stressable lightweight structures, with fiber-reinforced plastics and metal}, series = {3rd International MERGE Technologies Conference (IMTC), Chemnitz, 2017}, volume = {1}, booktitle = {3rd International MERGE Technologies Conference (IMTC), Chemnitz, 2017}, number = {2}, doi = {10.21935/tls.v1i2.76}, pages = {54 -- 67}, abstract = {Organic sheets made of fiber-reinforced thermoplastics can make a crucial contribution to increase the lightweight potential of a technical design. They show high specific strength- and stiffness properties as well as good damping characteristics, while being able to show a higher energy absorption capacity than comparable metal constructions. In addition, organic sheets provide good recycling capabilities. Nowadays, multi-material designs are an established way in the automotive industry to combine the benefits of metal and fiber-reinforced plastics (FRP). Currently used technologies for the joining of organic sheets and metals in large-scale production are mechanical joining and adhesive technologies. Both require large overlapping areas to achieve the desired joint strength and stiffness of the technical design. Additionally, mechanical joining is usually combined with "fiber-destroying" pre-drilling and punching processes. This will disturb the force flux at the joint zone by causing unwanted fiber- and inter-fiber failure and inducing critical notch stresses. Therefore, the multi-material design with fiber-reinforced thermoplastics and metals needs optimized joining techniques that don't interrupt the force flux, so that higher loads can be induced and the full benefit of the FRP material can be used. This article focuses on the characterization of a new joining technology, based on the Cold Metal Transfer (CMT) welding process, that allows to join organic sheets and metals in a load path optimized design. This is achieved by realigning the fibers around the joint zone by the integration of a thin metal pin. The alignment of the fibers will be similar to load paths of fibers inside structures found in nature. A tree with a knothole is always going to align its fibers in principle stress direction. As a result of the bionic fiber design, high joining strengths can be achieved. The increase of the joint strength compared to blind riveting was performed and proven with stainless steel and orthotropic reinforced composites in tensile shear-tests, based on the DIN EN ISO 14273.}, language = {en} } @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} }