TY - JOUR A1 - Fateri, Miranda A1 - Gebhardt, Andreas T1 - Additive manufactured mechanical disentanglement lock JF - RTejournal - Forum für Rapid Technologie Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0009-2-42147 SN - 1614-0923 VL - 12 PB - Fachhochschule Aachen CY - Aachen ER - TY - CHAP A1 - Großmann, Agnes A1 - Gabrielli, Roland Antonius A1 - Herdrich, Georg A1 - Fasoulas, Stefanos A1 - Schnauffer, Peter A1 - Middendorf, Peter A1 - Fateri, Miranda A1 - Gebhardt, Andreas T1 - Overview of the MultiRob 3D Lunar Industrial Development Project T2 - Conference Contribution for the 30th ISTS, Kobe, Japan, 04.07.-10.07.2015 Y1 - 2015 ER - TY - CHAP A1 - Alhwarin, Faraj A1 - Ferrein, Alexander A1 - Gebhardt, Andreas A1 - Kallweit, Stephan A1 - Scholl, Ingrid A1 - Tedjasukmana, Osmond Sanjaya T1 - Improving additive manufacturing by image processing and robotic milling T2 - 2015 IEEE International Conference on Automation Science and Engineering (CASE), Aug 24-28, 2015 Gothenburg, Sweden Y1 - 2015 U6 - http://dx.doi.org/10.1109/CoASE.2015.7294217 SP - 924 EP - 929 ER - TY - JOUR A1 - Kessler, Julia A1 - Balc, Nicolae A1 - Gebhardt, Andreas A1 - Abbas, Karim T1 - Basic Research on Lattice Structures Focused on the Tensile Strength JF - Applied Mechanics and Materials Y1 - 2015 U6 - http://dx.doi.org/10.4028/www.scientific.net/AMM.808.193 SN - 1662-7482 N1 - MTeM ; October 14-16, 2015, Cluj-Napoca, Romania VL - Vol. 808 SP - 193 EP - 198 PB - Trans Tech Publications CY - Bäch ER - TY - CHAP A1 - Fateri, Miranda A1 - Gebhardt, Andreas A1 - Gabrielli, Roland Antonius A1 - Herdrich, Georg A1 - Fasoulas, Stefanos A1 - Großmann, Agnes A1 - Schnauffer, Peter A1 - Middendorf, Peter T1 - Additive Manufacturing of Lunar Regolith for Extra-terrestrial Industry Plant T2 - International Symposium on Space Technology and Science (ICTS). July 2015, Kobe, Japan Y1 - 2015 ER - TY - CHAP A1 - Gabrielli, Roland Antonius A1 - Mathies, Johannes A1 - Großmann, Agnes A1 - Herdrich, Georg A1 - Fasoulas, Stefanos A1 - Middendorf, Peter A1 - Fateri, Miranda A1 - Gebhardt, Andreas T1 - Space Propulsion Considerations for a Lunar Take Off Industry Based on Regolith T2 - International Symposium on Space Technology and Science (ISTS). July 2015, Kobe, Japan Y1 - 2015 ER - TY - CHAP A1 - Fateri, Miranda A1 - Gebhardt, Andreas A1 - Renftle, Georg T1 - Additive Manufacturing of Drainage Segments for Cooling System of Crucibles Melting Furnaces T2 - International Conference and Expo on Advanced Ceramics and Composites, (ICACC). January 2015, Florida, USA N2 - The cooling process in induction based crucible melting furnaces for Industrial applications is one of the important and challenging factors in production and safety engineering. Accordingly, proper implementation of the cooling system of the furnace using optimum cooling guides and fail-safe features are critical in order to improve the safety of the process. Regarding this, manufacturing of porous material with high electrical isolation for the drainage segments of the cooling channels is examined in this study. Consequently, various geometries with different porosities using glass and ceramic powder are fabricated using Selective Laser Sintering (SLS) process. The manufactured parts are examined in a prototype furnace testing and the feasibility of the SLS manufacturing of parts for this application is discussed. Y1 - 2015 ER - TY - CHAP A1 - Kilic, S. A. A1 - Raatschen, Hans-Jürgen A1 - Astaneh-Asl, A. A1 - Apaydin, N. M. T1 - Finite element modeling of the Fatih Sultan Mehmet Suspension Bridge T2 - Multi-Span Large Bridges - Proceedings of the International Conference on Multi-Span Large Bridges Y1 - 2015 SN - 9781138027572 SP - 1169 EP - 1173 PB - CRC Press CY - Leiden ER - TY - CHAP A1 - Wollert, Jörg T1 - Wireless systems for machinery safety : Requirements and solutions for wireless real time systems T2 - 16th International Conference on Research and Education in Mechatronics (REM), 2015 Y1 - 2015 SN - 978-3-945728-01-7 U6 - http://dx.doi.org/10.1109/REM.2015.7380377 SP - 88 EP - 91 ER - TY - CHAP A1 - Nakagawa, Masaki A1 - Kallweit, Stephan A1 - Michaux, Frank A1 - Hojo, Teppei T1 - Typical Velocity Fields and Vortical Structures around a Formula One Car, based on Experimental Investigations using Particle Image Velocimetry T2 - SAE International Journal of Passenger Cars - Mechanical Systems Y1 - 2016 U6 - http://dx.doi.org/10.4271/2016-01-1611 SN - 1946-4002 ER - TY - BOOK A1 - Gebhardt, Andreas A1 - Hötter, Jan-Steffen T1 - Additive manufacturing : 3D printing for prototyping and manufacturing Y1 - 2016 SN - 978-1-56990-582-1 ; 978-1-56990-583-8 PB - Hanser Publishers CY - Munich 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 - http://dx.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 - http://dx.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 - http://dx.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 - http://dx.doi.org/10.1007/s13369-016-2316-y SN - 2191-4281 VL - 42 IS - 3 SP - 1103 EP - 1116 PB - Springer Nature ER - TY - JOUR A1 - Rieper, Harald A1 - Gebhardt, Andreas A1 - Stucker, Brent T1 - Selective Laser Melting of the Eutectic Silver-Copper Alloy Ag 28 wt % Cu JF - RTejournal - Forum für Rapid Technologie N2 - The aim of this work was to perform a detailed investigation of the use of Selective Laser Melting (SLM) technology to process eutectic silver-copper alloy Ag 28 wt. % Cu (also called AgCu28). The processing occurred with a Realizer SLM 50 desktop machine. The powder analysis (SEM-topography, EDX, particle distribution) was reported as well as the absorption rates for the near-infrared (NIR) spectrum. Microscope imaging showed the surface topography of the manufactured parts. Furthermore, microsections were conducted for the analysis of porosity. The Design of Experiments approach used the response surface method in order to model the statistical relationship between laser power, spot distance and pulse time. KW - SLM KW - Response Surface Method KW - Porositat KW - Eutectic Silver Copper alloy KW - Additive Manufacturing Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?nbn:de:0009-2-44141 SN - 1614-0923 VL - 13 ER - TY - JOUR A1 - Haag, S. A1 - Zontar, D. A1 - Schleupen, Josef A1 - Müller, T. A1 - Brecher, C. T1 - Chain of refined perception in self-optimizing assembly of micro-optical systems JF - Journal of sensors and sensor systems N2 - Today, the assembly of laser systems requires a large share of manual operations due to its complexity regarding the optimal alignment of optics. Although the feasibility of automated alignment of laser optics has been shown in research labs, the development effort for the automation of assembly does not meet economic requirements – especially for low-volume laser production. This paper presents a model-based and sensor-integrated assembly execution approach for flexible assembly cells consisting of a macro-positioner covering a large workspace and a compact micromanipulator with camera attached to the positioner. In order to make full use of available models from computer-aided design (CAD) and optical simulation, sensor systems at different levels of accuracy are used for matching perceived information with model data. This approach is named "chain of refined perception", and it allows for automated planning of complex assembly tasks along all major phases of assembly such as collision-free path planning, part feeding, and active and passive alignment. The focus of the paper is put on the in-process image-based metrology and information extraction used for identifying and calibrating local coordinate systems as well as the exploitation of that information for a part feeding process for micro-optics. Results will be presented regarding the processes of automated calibration of the robot camera as well as the local coordinate systems of part feeding area and robot base. Y1 - 2014 U6 - http://dx.doi.org/10.5194/jsss-3-87-2014 SN - 2194-878X VL - 3 IS - 1 SP - 87 EP - 95 PB - Copernicus Publ. CY - Göttingen ER - TY - CHAP A1 - Kessler, Julia A1 - Balc, Nicolae A1 - Gebhardt, Andreas T1 - Basic research on lattice structures focused on the strut shape and welding beads T2 - Physics Procedia Y1 - 2016 U6 - http://dx.doi.org/10.1016/j.phpro.2016.08.086 SN - 1875-3884 N1 - Laser Assisted Net Shape Engineering 9th International Conference on Photonic Technologies Proceedings of the LANE 2016 VL - Vol. 83 SP - 833 EP - 838 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 - http://dx.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 - TY - CHAP A1 - Schleupen, Josef A1 - Engemann, Heiko A1 - Bagheri, Mohsen A1 - Kallweit, Stephan A1 - Dahmann, Peter T1 - Developing a climbing maintenance robot for tower and rotor blade service of wind turbines T2 - Advances in Robot Design and Intelligent Control : Proceedings of the 25th Conference on Robotics in Alpe-Adria-Danube Region (RAAD16) Y1 - 2017 SN - 978-3-319-49058-8 U6 - http://dx.doi.org/10.1007/978-3-319-49058-8_34 N1 - Advances in Robot Design and Intelligent Control ; Vol. 540 SP - 310 EP - 319 PB - Springer CY - Cham ER -