TY - CHAP A1 - Wiesen, Andreas A1 - Schleser, Markus T1 - Entwicklung einer Qualitätssicherung für das Laserstrahlschweißen im Vakuum mittels Bildverarbeitung T2 - Große Schweißtechnische Tagung Y1 - 2019 SN - 978-3-96144-066-5 N1 - DVS CONGRESS 2019, Große Schweißtechnische Tagung, DVS-Studentenkongress. 16. bis 17. September 2019, Düsseldorf. DVS-Berichte, Band 355 SP - 1 EP - 6 PB - DVS-Media CY - Düsseldorf ER - TY - CHAP A1 - Otten, Christian A1 - Gerhards, Benjamin A1 - Schleser, Markus A1 - Schwarz, A. A1 - Gebhardt, Andreas T1 - Innovative Laserschweißtechnologie für additiv gefertigte Bauteile T2 - Große Schweißtechnische Tagung Y1 - 2019 SN - 978-3-96144-066-5 N1 - DVS CONGRESS 2019, Große Schweißtechnische Tagung, DVS-Studentenkongress. 16. bis 17. September 2019, Düsseldorf. DVS-Berichte, Band 355 SP - 150 EP - 157 PB - DVS-Media CY - Düsseldorf ER - TY - CHAP A1 - Fiedler, Gerda A1 - Henn, Gudrun A1 - Melcher, Karin ED - Morschheuser, Petra T1 - ANPAK - Ein Anpassungskurs für Studienanfänger in den Ingenieurwissenschaften T2 - Qualifizierung von Studierenden im Student-Life-Cycle. Tagungsband zum Mosbacher Tag der Lehre am 23.10.2014 / Y1 - 2015 SN - 978-3-943656-02-2 SP - 90 EP - 93 PB - Duale Hochschule Baden-Württemberg (DHBW) CY - Mosbach ER - TY - JOUR A1 - Cosma, Cosmin A1 - Kessler, Julia A1 - Gebhardt, Andreas A1 - Campbell, Ian A1 - Balc, Nicolae T1 - Improving the Mechanical Strength of Dental Applications and Lattice Structures SLM Processed JF - Materials N2 - To manufacture custom medical parts or scaffolds with reduced defects and high mechanical characteristics, new research on optimizing the selective laser melting (SLM) parameters are needed. In this work, a biocompatible powder, 316L stainless steel, is characterized to understand the particle size, distribution, shape and flowability. Examination revealed that the 316L particles are smooth, nearly spherical, their mean diameter is 39.09 μm and just 10% of them hold a diameter less than 21.18 μm. SLM parameters under consideration include laser power up to 200 W, 250–1500 mm/s scanning speed, 80 μm hatch spacing, 35 μm layer thickness and a preheated platform. The effect of these on processability is evaluated. More than 100 samples are SLM-manufactured with different process parameters. The tensile results show that is possible to raise the ultimate tensile strength up to 840 MPa, adapting the SLM parameters for a stable processability, avoiding the technological defects caused by residual stress. Correlating with other recent studies on SLM technology, the tensile strength is 20% improved. To validate the SLM parameters and conditions established, complex bioengineering applications such as dental bridges and macro-porous grafts are SLM-processed, demonstrating the potential to manufacture medical products with increased mechanical resistance made of 316L. Y1 - 2020 U6 - https://doi.org/10.3390/ma13040905 SN - 1996-1944 VL - 13 IS - 4 SP - 1 EP - 18 PB - MDPI CY - Basel ER - TY - BOOK A1 - Feuerriegel, Uwe T1 - Wärmeübertragung mit EXCEL und VBA: Wärmetechnische Berechnungen und Simulationen effektiv durchführen und professionell dokumentieren N2 - Dieses Lehrbuch vermittelt die Grundlagen der Wärmeübertragung sowie den Umgang mit EXCEL-VBA von der Erstellung von Makros bis zu benutzerdefinierten Funktionen. Es legt damit eine Basis für die schnelle und professionelle Durchführung von Berechnungen und Simulationen. Die angeleitete Erstellung von Berechnungsmodulen mit EXCEL und VBA aus allen wichtigen Bereichen der Wärmeübertragung bildet den inhaltlichen Schwerpunkt. Dazu zählen die stationäre Wärmeleitung und der stationäre Wärmedurchgang, die instationäre Wärmeleitung, der Wärmeübergang bei freier und erzwungener Konvektion sowie die Wärmestrahlung und der Wärmeübergang beim Kondensieren und Sieden. Soweit sinnvoll und möglich werden die Stoffwertekorrelationen und die Berechnungsvorschriften aus dem VDI-Wärmeatlas verwendet. Für ausgewählte Anwendungen werden zudem komplexere Auslegungen und Simulationen von Prozessen der Wärmeübertragung sowie von Wärmeübertragern erstellt. Die Zielgruppen: Studierende in Bachelor- und Masterstudiengängen, Praktiker im Engineering KW - Wärmeübertragung KW - Energietechnik KW - Excel und VBA KW - VDI-Wärmeatlas KW - Wärmeübertrager Y1 - 2021 SN - 978-3-658-35905-8 U6 - https://doi.org/10.1007/978-3-658-35906-5 N1 - In der Bereichsbibliothek Eupener Straße unter der Signatur 21 WDW 39 vorhanden PB - Springer Vieweg CY - Wiesbaden ER - TY - CHAP A1 - Fiedler, Gerda A1 - Gottschlich-Müller, Birgit A1 - Melcher, Karin ED - Liu-Henke, Xiaobo ED - Durak, Umut T1 - Online-Prüfungen mit STACK Aufgaben T2 - Tagungsband ASIM Workshop STS/GMMS/EDU 2021 N2 - Wir stellen hier exemplarisch STACK Aufgaben vor, die frei von der Problematik sind, welche sich durch diverse Kommunikationswege und (webbasierte) Computer Algebra Systeme (CAS) ergibt. Daher sind sie insbesondere für eine Open-Book Online Prüfung geeignet, da eine faire Prüfungssituation gewährleistet werden kann. Y1 - 2021 SN - 978-3-901608-69-8 U6 - https://doi.org/10.11128/arep.45 N1 - Virtueller Workshop, ASIM STS/GMMS & EDU 2021, 11.-12. März 2021 SP - 173 EP - 178 PB - ARGESIM Verlag CY - Wien ER - TY - JOUR A1 - Koster, Arie A1 - Scheidweiler, Robert A1 - Tieves, Martin T1 - A flow based pruning scheme for enumerative equitable coloring algorithms JF - A flow based pruning scheme for enumerative equitable coloring algorithms N2 - An equitable graph coloring is a proper vertex coloring of a graph G where the sizes of the color classes differ by at most one. The equitable chromatic number is the smallest number k such that G admits such equitable k-coloring. We focus on enumerative algorithms for the computation of the equitable coloring number and propose a general scheme to derive pruning rules for them: We show how the extendability of a partial coloring into an equitable coloring can be modeled via network flows. Thus, we obtain pruning rules which can be checked via flow algorithms. Computational experiments show that the search tree of enumerative algorithms can be significantly reduced in size by these rules and, in most instances, such naive approach even yields a faster algorithm. Moreover, the stability, i.e., the number of solved instances within a given time limit, is greatly improved. Since the execution of flow algorithms at each node of a search tree is time consuming, we derive arithmetic pruning rules (generalized Hall-conditions) from the network model. Adding these rules to an enumerative algorithm yields an even larger runtime improvement. Y1 - 2016 U6 - https://doi.org/10.48550/arXiv.1607.08754 N1 - Lehrstuhl II für Mathematik, RWTH Aachen University SP - 1 EP - 30 ER - TY - JOUR A1 - Beckenbach, Isabel A1 - Scheidweiler, Robert T1 - Perfect ƒ-Matchings and ƒ-Factors in Hypergraphs - A Combinatorial Approach JF - Discrete Mathematics N2 - We prove characterizations of the existence of perfect ƒ-matchings in uniform mengerian and perfect hypergraphs. Moreover, we investigate the ƒ-factor problem in balanced hypergraphs. For uniform balanced hypergraphs we prove two existence theorems with purely combinatorial arguments, whereas for non-uniform balanced hypergraphs we show that the ƒ-factor problem is NP-hard. Y1 - 2016 U6 - https://doi.org/10.1016/j.disc.2017.05.005 SN - 2192-7782 N1 - Als Volltext auch bei ZIB (Zuse Institute Berlin) VL - 240 IS - 10 SP - 2499 EP - 2506 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Scheidweiler, Robert A1 - Triesch, Eberhard T1 - A note on the duality between matchings and vertex covers in balanced hypergraphs JF - Journal of Combinatorial Optimization N2 - We present a new Min-Max theorem for an optimization problem closely connected to matchings and vertex covers in balanced hypergraphs. The result generalizes Kőnig’s Theorem (Berge and Las Vergnas in Ann N Y Acad Sci 175:32–40, 1970; Fulkerson et al. in Math Progr Study 1:120–132, 1974) and Hall’s Theorem (Conforti et al. in Combinatorica 16:325–329, 1996) for balanced hypergraphs. KW - Hall’s Theorem KW - Koenig’s Theorem KW - Duality KW - Balanced hypergraph KW - Hypergraph KW - Vertex cover KW - Matching Y1 - 2016 U6 - https://doi.org/10.1007/s10878-015-9887-5 SN - 1573-2886 N1 - Lehrstuhl II für Mathematik RWTH Aachen VL - 32 IS - 2 SP - 639 EP - 644 PB - Springer CY - Berlin ER - TY - JOUR A1 - Kilic, S. A. A1 - Raatschen, Hans-Jürgen A1 - Körfgen, B. A1 - Apaydin, N. M. A1 - Astaneh-Asl, A. T1 - FE Model of the Fatih Sultan Mehmet Suspension Bridge Using Thin Shell Finite Elements JF - Arabian Journal for Science and Engineering N2 - This paper presents the results of an eigenvalue analysis of the Fatih Sultan Mehmet Bridge. A high-resolution finite element model was created directly from the available design documents. All physical properties of the structural components were included in detail, so no calibration to the measured data was necessary. The deck and towers were modeled with shell elements. A nonlinear static analysis was performed before the eigenvalue calculation. The calculated natural frequencies and corresponding mode shapes showed good agreement with the available measured ambient vibration data. The calculation of the effective modal mass showed that nine modes had single contributions higher than 5 % of the total mass. They were in a frequency range up to 1.2 Hz. The comparison of the results for the torsional modes especially demonstrated the advantage of using thin shell finite elements over the beam modeling approach. KW - Suspension bridge KW - 3D nonlinear finite element model KW - Thin shell finite elements KW - Natural frequency KW - Effective modal mass Y1 - 2017 U6 - https://doi.org/10.1007/s13369-016-2316-y SN - 2191-4281 VL - 42 IS - 3 SP - 1103 EP - 1116 PB - Springer Nature ER - TY - CHAP A1 - Engemann, Heiko A1 - Wiesen, Patrick A1 - Kallweit, Stephan A1 - Deshpande, Harshavardhan A1 - Schleupen, Josef T1 - Autonomous mobile manipulation using ROS T2 - Advances in Service and Industrial Robotics Y1 - 2018 SN - 978-3-319-61276-8 U6 - https://doi.org/10.1007/978-3-319-61276-8_43 N1 - International Conference on Robotics in Alpe-Adria Danube Region RAAD 2017; Mechanisms and Machince Science book series, Vol 49. SP - 389 EP - 401 PB - Springer CY - Cham ER - TY - CHAP A1 - Fateri, Miranda A1 - Gebhardt, Andreas A1 - Renftle, Georg T1 - Additive manufacturing of drainage segments for cooling system of crucible melting furnaces T2 - Advanced Processing and Manufacturing Technologies for Structural and Multifunctional Materials II, International Symposium on Advanced Processing and Manufacturing Technologies for Structural and Multifunctional Materials, ICACC 15, 39th International Conference on Advanced Ceramics and Composites, Daytona Beach, FL, US, Jan 25-30, 2015 Y1 - 2015 U6 - https://doi.org/10.1002/9781119211662.ch14 SN - 0196-6219 SP - 123 EP - 131 PB - Wiley CY - Hoboken ER - TY - CHAP A1 - Engemann, Heiko A1 - Badri, Sriram A1 - Wenning, Marius A1 - Kallweit, Stephan T1 - Implementation of an Autonomous Tool Trolley in a Production Line T2 - Advances in Service and Industrial Robotics. RAAD 2019. Advances in Intelligent Systems and Computing, vol 980 Y1 - 2019 SN - 978-3-030-19648-6 U6 - https://doi.org/10.1007/978-3-030-19648-6_14 SP - 117 EP - 125 PB - Springer CY - Cham ER - TY - JOUR A1 - Schwarz, Alexander A1 - Gebhardt, Andreas A1 - Schleser, Markus A1 - Popoola, Patricia T1 - New Welding Joint Geometries Manufactured by Powder Bed Fusion from 316L JF - Materials Performance and Characterization 8 Y1 - 2019 U6 - https://doi.org/10.1520/MPC20180096 SN - 2379-1365 IS - in press ER - TY - JOUR A1 - Bucur, Alexandru A1 - Lazarescu, Lucian A1 - Pop, Grigore Marian A1 - Achimas, Gheorghe A1 - Gebhardt, Andreas T1 - Tribological performance of biodegradable lubricants under different surface roughness of tools JF - Academic Journal of Manufacturing Engineering Y1 - 2019 SN - 1583-7904 VL - 17 IS - 1 SP - 172 EP - 178 ER - TY - JOUR A1 - Franko, Josef A1 - Du, Shengzhi A1 - Kallweit, Stephan A1 - Duelberg, Enno Sebastian A1 - Engemann, Heiko T1 - Design of a Multi-Robot System for Wind Turbine Maintenance JF - Energies N2 - The maintenance of wind turbines is of growing importance considering the transition to renewable energy. This paper presents a multi-robot-approach for automated wind turbine maintenance including a novel climbing robot. Currently, wind turbine maintenance remains a manual task, which is monotonous, dangerous, and also physically demanding due to the large scale of wind turbines. Technical climbers are required to work at significant heights, even in bad weather conditions. Furthermore, a skilled labor force with sufficient knowledge in repairing fiber composite material is rare. Autonomous mobile systems enable the digitization of the maintenance process. They can be designed for weather-independent operations. This work contributes to the development and experimental validation of a maintenance system consisting of multiple robotic platforms for a variety of tasks, such as wind turbine tower and rotor blade service. In this work, multicopters with vision and LiDAR sensors for global inspection are used to guide slower climbing robots. Light-weight magnetic climbers with surface contact were used to analyze structure parts with non-destructive inspection methods and to locally repair smaller defects. Localization was enabled by adapting odometry for conical-shaped surfaces considering additional navigation sensors. Magnets were suitable for steel towers to clamp onto the surface. A friction-based climbing ring robot (SMART— Scanning, Monitoring, Analyzing, Repair and Transportation) completed the set-up for higher payload. The maintenance period could be extended by using weather-proofed maintenance robots. The multi-robot-system was running the Robot Operating System (ROS). Additionally, first steps towards machine learning would enable maintenance staff to use pattern classification for fault diagnosis in order to operate safely from the ground in the future. Y1 - 2020 U6 - https://doi.org/10.3390/en13102552 SN - 1996-1073 VL - 13 IS - 10 SP - Article 2552 PB - MDPI CY - Basel ER - TY - JOUR A1 - Kunkel, Maximilian Hugo A1 - Gebhardt, Andreas A1 - Mpofu, Khumbulani A1 - Kallweit, Stephan T1 - Quality assurance in metal powder bed fusion via deep-learning-based image classification JF - Rapid Prototyping Journal Y1 - 2019 U6 - https://doi.org/10.1108/RPJ-03-2019-0066 SN - 1355-2546 VL - 26 IS - 2 SP - 259 EP - 266 ER - TY - CHAP A1 - Adenacker, J. A1 - Gerhards, Benjamin A1 - Otten, Christian A1 - Schleser, Markus T1 - Laserstrahlschweißen von Aluminium-Kupfer-Werkstoffkombinationen für die Elektromobilität T2 - DVS CONGRESS 2021 Y1 - 2021 SN - 978-3-96144-146-4 N1 - DVS CONGRESS 2021, 14. – 17. September 2021, Essen. Große Schweißtechnische Tagung 2021, DVS CAMPUS 2021. DVS Berichte, Band: 371 SP - 31 EP - 38 PB - DVS Media GmbH CY - Düsseldorf ER - TY - JOUR A1 - Zabirov, Alexander A1 - Schleser, Markus A1 - Bucherer, Sebastian T1 - Füge- und Dichtkonzept für einen Leichtbauverbrennungsmotor JF - adhäsion KLEBEN & DICHTEN Y1 - 2021 U6 - https://doi.org/10.1007/s35145-021-0531-5 SN - 2192-8681 VL - 65 IS - 11 SP - 12 EP - 19 PB - Springer Nature CY - Cham ER - TY - CHAP A1 - Kessler, Julia A1 - Balc, Nicolae A1 - Gebhardt, Andreas A1 - Abbas, Karim T1 - Basic research on lattice structures focused on the reliance of the cross sectional area and additional coatings T2 - The 4th International Conference on Computing and Solutions in Manufacturing Engineering 2016 – CoSME’16 Y1 - 2017 U6 - https://doi.org/10.1051/matecconf/20179403008 N1 - MATEC Web Conf. Vol 94, 2017, 03008 MATEC Web of Conferences 94, 03008 (2017) ET - Vol. 94 ER -