@inproceedings{NakagawaMichauxKallweitetal.2015, author = {Nakagawa, Masaki and Michaux, Frank and Kallweit, Stephan and Maeda, Kazuhiro}, title = {Unsteady flow measurements in the wake behind a wind-tunnel car model by using high-speed planar PIV}, series = {11TH International Symposium on Particle Image Velocimetry - PIV15 Santa Barbara, California, September 14-16, 2015}, booktitle = {11TH International Symposium on Particle Image Velocimetry - PIV15 Santa Barbara, California, September 14-16, 2015}, pages = {21 S.}, year = {2015}, abstract = {This study investigates unsteady characteristics of the wake behind a 28\%-scale car model in a wind tunnel using highspeed planar particle image velocimetry (PIV). The car model is based on a hatchback passenger car that is known to have relatively high fluctuations in its aerodynamic loads. This study primarily focuses on the lateral motion of the flow on the horizontal plane to determine the effect of the flow motion on the straight-line stability and the initial steering response of the actual car on a track. This paper first compares the flow fields in the wake behind the above mentioned model obtained using conventional and high-speed planar PIV, with sampling frequencies of 8 Hz and 1 kHz, respectively. Large asymmetrically coherent flow structures, which fluctuate at frequencies below 2 Hz, are observed in the results of highspeed PIV measurements, whereas conventional PIV is unable to capture these features of the flow owing to aliasing. This flow pattern with a laterally swaying motion is represented by opposite signs of cross-correlation coefficients of streamwise velocity fluctuations for the two sides of the car model. Effects of two aerodynamic devices that are known to reduce the fluctuation levels of the aerodynamic loads are then extensively investigated. The correlation analyses reveal that these devices indeed reduce the fluctuation levels of the flow and the correlation values around the rear combination-lamp, but it is found that the effects of these devices are different around the c-pillar.}, language = {en} } @inproceedings{KilicRaatschenAstanehAsletal.2015, author = {Kilic, S. A. and Raatschen, Hans-J{\"u}rgen and Astaneh-Asl, A. and Apaydin, N. M.}, title = {Finite element modeling of the Fatih Sultan Mehmet Suspension Bridge}, series = {Multi-Span Large Bridges - Proceedings of the International Conference on Multi-Span Large Bridges}, booktitle = {Multi-Span Large Bridges - Proceedings of the International Conference on Multi-Span Large Bridges}, publisher = {CRC Press}, address = {Leiden}, isbn = {9781138027572}, pages = {1169 -- 1173}, year = {2015}, language = {en} } @inproceedings{Wollert2015, author = {Wollert, J{\"o}rg}, title = {Wireless systems for machinery safety : Requirements and solutions for wireless real time systems}, series = {16th International Conference on Research and Education in Mechatronics (REM), 2015}, booktitle = {16th International Conference on Research and Education in Mechatronics (REM), 2015}, isbn = {978-3-945728-01-7}, doi = {10.1109/REM.2015.7380377}, pages = {88 -- 91}, year = {2015}, language = {en} } @inproceedings{NakagawaKallweitMichauxetal.2016, author = {Nakagawa, Masaki and Kallweit, Stephan and Michaux, Frank and Hojo, Teppei}, title = {Typical Velocity Fields and Vortical Structures around a Formula One Car, based on Experimental Investigations using Particle Image Velocimetry}, series = {SAE International Journal of Passenger Cars - Mechanical Systems}, booktitle = {SAE International Journal of Passenger Cars - Mechanical Systems}, issn = {1946-4002}, doi = {10.4271/2016-01-1611}, pages = {18 S.}, year = {2016}, language = {en} } @book{GebhardtHoetter2016, author = {Gebhardt, Andreas and H{\"o}tter, Jan-Steffen}, title = {Additive manufacturing : 3D printing for prototyping and manufacturing}, publisher = {Hanser Publishers}, address = {Munich}, isbn = {978-1-56990-582-1 ; 978-1-56990-583-8}, pages = {591 S.}, year = {2016}, language = {en} } @article{KosterScheidweilerTieves2016, author = {Koster, Arie and Scheidweiler, Robert and Tieves, Martin}, title = {A flow based pruning scheme for enumerative equitable coloring algorithms}, series = {A flow based pruning scheme for enumerative equitable coloring algorithms}, journal = {A flow based pruning scheme for enumerative equitable coloring algorithms}, doi = {10.48550/arXiv.1607.08754}, pages = {1 -- 30}, year = {2016}, abstract = {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.}, language = {en} } @article{BeckenbachScheidweiler2016, author = {Beckenbach, Isabel and Scheidweiler, Robert}, title = {Perfect ƒ-Matchings and ƒ-Factors in Hypergraphs - A Combinatorial Approach}, series = {Discrete Mathematics}, volume = {240}, journal = {Discrete Mathematics}, number = {10}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2192-7782}, doi = {10.1016/j.disc.2017.05.005}, pages = {2499 -- 2506}, year = {2016}, abstract = {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.}, language = {en} } @article{ScheidweilerTriesch2016, author = {Scheidweiler, Robert and Triesch, Eberhard}, title = {A note on the duality between matchings and vertex covers in balanced hypergraphs}, series = {Journal of Combinatorial Optimization}, volume = {32}, journal = {Journal of Combinatorial Optimization}, number = {2}, publisher = {Springer}, address = {Berlin}, issn = {1573-2886}, doi = {10.1007/s10878-015-9887-5}, pages = {639 -- 644}, year = {2016}, abstract = {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.}, language = {en} } @article{KilicRaatschenKoerfgenetal.2017, author = {Kilic, S. A. and Raatschen, Hans-J{\"u}rgen and K{\"o}rfgen, B. and Apaydin, N. M. and Astaneh-Asl, A.}, title = {FE Model of the Fatih Sultan Mehmet Suspension Bridge Using Thin Shell Finite Elements}, series = {Arabian Journal for Science and Engineering}, volume = {42}, journal = {Arabian Journal for Science and Engineering}, number = {3}, publisher = {Springer Nature}, issn = {2191-4281}, doi = {10.1007/s13369-016-2316-y}, pages = {1103 -- 1116}, year = {2017}, abstract = {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.}, language = {en} } @article{RieperGebhardtStucker2016, author = {Rieper, Harald and Gebhardt, Andreas and Stucker, Brent}, title = {Selective Laser Melting of the Eutectic Silver-Copper Alloy Ag 28 wt \% Cu}, series = {RTejournal - Forum f{\"u}r Rapid Technologie}, volume = {13}, journal = {RTejournal - Forum f{\"u}r Rapid Technologie}, issn = {1614-0923}, url = {http://nbn-resolving.de/nbn:de:0009-2-44141}, year = {2016}, abstract = {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.}, language = {en} } @article{HaagZontarSchleupenetal.2014, author = {Haag, S. and Zontar, D. and Schleupen, Josef and M{\"u}ller, T. and Brecher, C.}, title = {Chain of refined perception in self-optimizing assembly of micro-optical systems}, series = {Journal of sensors and sensor systems}, volume = {3}, journal = {Journal of sensors and sensor systems}, number = {1}, publisher = {Copernicus Publ.}, address = {G{\"o}ttingen}, issn = {2194-878X}, doi = {10.5194/jsss-3-87-2014}, pages = {87 -- 95}, year = {2014}, abstract = {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.}, language = {en} } @inproceedings{KesslerBalcGebhardt2016, author = {Kessler, Julia and Balc, Nicolae and Gebhardt, Andreas}, title = {Basic research on lattice structures focused on the strut shape and welding beads}, series = {Physics Procedia}, volume = {Vol. 83}, booktitle = {Physics Procedia}, issn = {1875-3884}, doi = {10.1016/j.phpro.2016.08.086}, pages = {833 -- 838}, year = {2016}, language = {en} } @inproceedings{KesslerBalcGebhardtetal.2017, author = {Kessler, Julia and Balc, Nicolae and Gebhardt, Andreas and Abbas, Karim}, title = {Basic research on lattice structures focused on the reliance of the cross sectional area and additional coatings}, series = {The 4th International Conference on Computing and Solutions in Manufacturing Engineering 2016 - CoSME'16}, booktitle = {The 4th International Conference on Computing and Solutions in Manufacturing Engineering 2016 - CoSME'16}, edition = {Vol. 94}, doi = {10.1051/matecconf/20179403008}, pages = {7 S.}, year = {2017}, language = {en} } @inproceedings{SchleupenEngemannBagherietal.2017, author = {Schleupen, Josef and Engemann, Heiko and Bagheri, Mohsen and Kallweit, Stephan and Dahmann, Peter}, title = {Developing a climbing maintenance robot for tower and rotor blade service of wind turbines}, series = {Advances in Robot Design and Intelligent Control : Proceedings of the 25th Conference on Robotics in Alpe-Adria-Danube Region (RAAD16)}, booktitle = {Advances in Robot Design and Intelligent Control : Proceedings of the 25th Conference on Robotics in Alpe-Adria-Danube Region (RAAD16)}, publisher = {Springer}, address = {Cham}, isbn = {978-3-319-49058-8}, doi = {10.1007/978-3-319-49058-8_34}, pages = {310 -- 319}, year = {2017}, language = {en} } @inproceedings{ThurnGebhardt2017, author = {Thurn, Laura and Gebhardt, Andreas}, title = {Arousing Enthusiasm for STEM: Teaching 3D Printing Technology}, series = {Conference Proceedings: New Perspectives in Science Education}, booktitle = {Conference Proceedings: New Perspectives in Science Education}, publisher = {liberiauniversitaria.it}, address = {Padua}, isbn = {978-88-6292-847-2}, pages = {87 -- 92}, year = {2017}, language = {en} } @inproceedings{EngemannWiesenKallweitetal.2018, author = {Engemann, Heiko and Wiesen, Patrick and Kallweit, Stephan and Deshpande, Harshavardhan and Schleupen, Josef}, title = {Autonomous mobile manipulation using ROS}, series = {Advances in Service and Industrial Robotics}, booktitle = {Advances in Service and Industrial Robotics}, publisher = {Springer}, address = {Cham}, isbn = {978-3-319-61276-8}, doi = {10.1007/978-3-319-61276-8_43}, pages = {389 -- 401}, year = {2018}, language = {en} } @inproceedings{KleineKallweitMichauxetal.2016, author = {Kleine, Harald and Kallweit, Stephan and Michaux, Frank and Havermann, Marc and Olivier, Herbert}, title = {PIV Measurement of Shock Wave Diffraction}, series = {18th International Symposium on Applications of Laser Techniques to Fluid Mechanics, 2016, Lissabon}, booktitle = {18th International Symposium on Applications of Laser Techniques to Fluid Mechanics, 2016, Lissabon}, pages = {1 -- 14}, year = {2016}, language = {en} } @inproceedings{SchleupenEngemannBagherietal.2016, author = {Schleupen, Josef and Engemann, Heiko and Bagheri, Mohsen and Kallweit, Stephan}, title = {The potential of SMART climbing robot combined with a weatherproof cabin for rotor blade maintenance}, series = {17th European Conference on Composite Materials - ECCM, Munich, Germany}, booktitle = {17th European Conference on Composite Materials - ECCM, Munich, Germany}, pages = {1 -- 8}, year = {2016}, language = {en} } @inproceedings{PfaffSchmidtEnning2017, author = {Pfaff, Raphael and Schmidt, B. D. and Enning, Manfred}, title = {Towards inclusion of the freight rail system in the industrial internet of things - Wagon 4.0}, series = {Stephenson Conference, London, March 2017}, booktitle = {Stephenson Conference, London, March 2017}, pages = {1 -- 10}, year = {2017}, language = {en} } @inproceedings{ThurnBalcGebhardtetal.2017, author = {Thurn, Laura and Balc, Nicolae and Gebhardt, Andreas and Kessler, Julia}, title = {Education packed in technology to promote innovations: Teaching Additive Manufacturing based on a rolling Lab}, series = {Modern Technologies in Manufacturing (MTeM 2017 - AMaTUC)}, booktitle = {Modern Technologies in Manufacturing (MTeM 2017 - AMaTUC)}, issn = {2261-236X}, doi = {10.1051/matecconf/201713702013}, pages = {6 Seiten}, year = {2017}, language = {en} }