@inproceedings{BergmannGoettenBraunetal.2022, author = {Bergmann, Ole and G{\"o}tten, Falk and Braun, Carsten and Janser, Frank}, title = {Comparison and evaluation of blade element methods against RANS simulations and test data}, series = {CEAS Aeronautical Journal}, volume = {13}, booktitle = {CEAS Aeronautical Journal}, publisher = {Springer}, address = {Wien}, issn = {1869-5590 (Online)}, doi = {10.1007/s13272-022-00579-1}, pages = {535 -- 557}, year = {2022}, abstract = {This paper compares several blade element theory (BET) method-based propeller simulation tools, including an evaluation against static propeller ground tests and high-fidelity Reynolds-Average Navier Stokes (RANS) simulations. Two proprietary propeller geometries for paraglider applications are analysed in static and flight conditions. The RANS simulations are validated with the static test data and used as a reference for comparing the BET in flight conditions. The comparison includes the analysis of varying 2D aerodynamic airfoil parameters and different induced velocity calculation methods. The evaluation of the BET propeller simulation tools shows the strength of the BET tools compared to RANS simulations. The RANS simulations underpredict static experimental data within 10\% relative error, while appropriate BET tools overpredict the RANS results by 15-20\% relative error. A variation in 2D aerodynamic data depicts the need for highly accurate 2D data for accurate BET results. The nonlinear BET coupled with XFOIL for the 2D aerodynamic data matches best with RANS in static operation and flight conditions. The novel BET tool PropCODE combines both approaches and offers further correction models for highly accurate static and flight condition results.}, language = {en} } @inproceedings{BaaderReiswichBartschetal.2018, author = {Baader, Fabian and Reiswich, M. and Bartsch, M. and Keller, D. and Tiede, E. and Keck, G. and Demircian, A. and Friedrich, M. and Dachwald, Bernd and Sch{\"u}ller, K. and Lehmann, R. and Chojetzki, R. and Durand, C. and Rapp, L. and Kowalski, Julia and F{\"o}rstner, R.}, title = {VIPER - Student research on extraterrestrical ice penetration technology}, series = {Proceedings of the 2nd Symposium on Space Educational Activities}, booktitle = {Proceedings of the 2nd Symposium on Space Educational Activities}, pages = {1 -- 6}, year = {2018}, abstract = {Recent analysis of scientific data from Cassini and earth-based observations gave evidence for a global ocean under a surrounding solid ice shell on Saturn's moon Enceladus. Images of Enceladus' South Pole showed several fissures in the ice shell with plumes constantly exhausting frozen water particles, building up the E-Ring, one of the outer rings of Saturn. In this southern region of Enceladus, the ice shell is considered to be as thin as 2 km, about an order of magnitude thinner than on the rest of the moon. Under the ice shell, there is a global ocean consisting of liquid water. Scientists are discussing different approaches the possibilities of taking samples of water, i.e. by melting through the ice using a melting probe. FH Aachen UAS developed a prototype of maneuverable melting probe which can navigate through the ice that has already been tested successfully in a terrestrial environment. This means no atmosphere and or ambient pressure, low ice temperatures of around 100 to 150K (near the South Pole) and a very low gravity of 0,114 m/s^2 or 1100 μg. Two of these influencing measures are about to be investigated at FH Aachen UAS in 2017, low ice temperature and low ambient pressure below the triple point of water. Low gravity cannot be easily simulated inside a large experiment chamber, though. Numerical simulations of the melting process at RWTH Aachen however are showing a gravity dependence of melting behavior. Considering this aspect, VIPER provides a link between large-scale experimental simulations at FH Aachen UAS and numerical simulations at RWTH Aachen. To analyze the melting process, about 90 seconds of experiment time in reduced gravity and low ambient pressure is provided by the REXUS rocket. In this time frame, the melting speed and contact force between ice and probes are measured, as well as heating power and a two-dimensional array of ice temperatures. Additionally, visual and infrared cameras are used to observe the melting process.}, language = {en} } @inproceedings{JungFrotscherStaat2018, author = {Jung, Alexander and Frotscher, Ralf and Staat, Manfred}, title = {Electromechanical model of hiPSC-derived ventricular cardiomyocytes cocultured with fibroblasts}, series = {6th European Conference on Computational Mechanics (ECCM 6), 7th European Conference on Computational Fluid Dynamics (ECFD 7), 11-15 June 2018, Glasgow, UK}, booktitle = {6th European Conference on Computational Mechanics (ECCM 6), 7th European Conference on Computational Fluid Dynamics (ECFD 7), 11-15 June 2018, Glasgow, UK}, pages = {11 Seiten}, year = {2018}, abstract = {The CellDrum provides an experimental setup to study the mechanical effects of fibroblasts co-cultured with hiPSC-derived ventricular cardiomyocytes. Multi-scale computational models based on the Finite Element Method are developed. Coupled electrical cardiomyocyte-fibroblast models (cell level) are embedded into reaction-diffusion equations (tissue level) which compute the propagation of the action potential in the cardiac tissue. Electromechanical coupling is realised by an excitation-contraction model (cell level) and the active stress arising during contraction is added to the passive stress in the force balance, which determines the tissue displacement (tissue level). Tissue parameters in the model can be identified experimentally to the specific sample.}, language = {en} } @inproceedings{SchreiberKraftZuendorf2017, author = {Schreiber, Marc and Kraft, Bodo and Z{\"u}ndorf, Albert}, title = {Metrics Driven Research Collaboration: Focusing on Common Project Goals Continuously}, series = {39th International Conference on Software Engineering, May 20-28, 2017 - Buenos Aires, Argentina}, booktitle = {39th International Conference on Software Engineering, May 20-28, 2017 - Buenos Aires, Argentina}, pages = {8 Seiten}, year = {2017}, abstract = {Research collaborations provide opportunities for both practitioners and researchers: practitioners need solutions for difficult business challenges and researchers are looking for hard problems to solve and publish. Nevertheless, research collaborations carry the risk that practitioners focus on quick solutions too much and that researchers tackle theoretical problems, resulting in products which do not fulfill the project requirements. In this paper we introduce an approach extending the ideas of agile and lean software development. It helps practitioners and researchers keep track of their common research collaboration goal: a scientifically enriched software product which fulfills the needs of the practitioner's business model. This approach gives first-class status to application-oriented metrics that measure progress and success of a research collaboration continuously. Those metrics are derived from the collaboration requirements and help to focus on a commonly defined goal. An appropriate tool set evaluates and visualizes those metrics with minimal effort, and all participants will be pushed to focus on their tasks with appropriate effort. Thus project status, challenges and progress are transparent to all research collaboration members at any time.}, language = {en} } @inproceedings{GoettscheKornAmato2015, author = {G{\"o}ttsche, Joachim and Korn, Michael and Amato, Alexandre}, title = {The Passivhaus concept for the Arabian Peninsula - An energetic-economical evaluation considering the thermal comfort}, series = {QScience Proceedings: Vol 2015}, booktitle = {QScience Proceedings: Vol 2015}, doi = {10.5339/qproc.2015.qgbc.38}, pages = {8 Seiten}, year = {2015}, abstract = {The Passivhaus building standard is a concept developed for the realization of energy-efficient and economical buildings with a simultaneous high utilization comfort under European climate conditions. Major elements of the Passivhaus concept are a high thermal insulation of the external walls, the use of heat and/or solar shading glazing as well as an airtight building envelope in combination with energy-efficient technical building installations and heating or cooling generators, such as an efficient energy-recovery in the building air-conditioning. The objective of this research project is the inquiry to determine the parameters or constraints under which the Passivhaus concept can be implemented under the arid climate conditions in the Arabian Peninsula to achieve an energy-efficient and economical building with high utilization comfort. In cooperation between the Qatar Green Building Council (QGBC), Barwa Real Estate (BRE) and Kahramaa the first Passivhaus was constructed in Qatar and on the Arabian Peninsula in 2013. The Solar-Institut J{\"u}lich of Aachen University of Applied Science supports the Qatar Green Building Council with a dynamic building and equipment simulation of the Passivhaus and the neighbouring reference building. This includes simulation studies with different component configurations for the building envelope and different control strategies for heating or cooling systems as well as the air conditioning of buildings to find an energetic-economical optimum. Part of these analyses is the evaluation of the energy efficiency of the used energy recovery system in the Passivhaus air-conditioning and identification of possible energy-saving effects by the use of a bypass function integrated in the heat exchanger. In this way it is expected that on an annual basis the complete electricity demand of the building can be covered by the roof-integrated PV generator.}, language = {en} } @inproceedings{FredebeulKrein2016, author = {Fredebeul-Krein, Markus}, title = {Towards trade facilitation via regulatory convergence: An analysis of the TTIP chapter on Electronic Communications}, series = {Regional ITS Conference of the International Telecommunications Society. Cambridge, United Kingdom, 7-9 September 2016}, booktitle = {Regional ITS Conference of the International Telecommunications Society. Cambridge, United Kingdom, 7-9 September 2016}, pages = {29 Seiten}, year = {2016}, abstract = {To give the exchange of goods and services between the European Union (EU) and the United States (U.S.) new momentum the two parties are currently negotiating the transatlantic free trade agreement Transatlantic Trade and Investment Partnership (TTIP). The aim is to create the largest free trade area in the world. The agreement, once entered into force, will oblige EU countries and the U.S. to further liberalize their markets. The negotiations on TTIP include a chapter on Electronic Communications/ Telecommunications. The challenge therein will be securing commitments for market access to Electronic Communications services. At the same time, these commitments must reflect the legitimate need for consumer protection issues. The need to reduce Electronic Communications-related non-tariff barriers to trade between the Parties is due to the fact that these markets are heavily regulated. Without transnational rules as to regulations national governments can abuse these regulations to deter the market entry by new (foreign) suppliers. Thus the free trade agreement TTIP affects in many respects regulatory provisions on and access to Electronic Communications markets. The objective of this paper is therefore to examine to what extend the regulatory principles for Electronic Communications markets envisaged under TTIP will result in trade facilitation and regulatory convergence between the EU and the U.S. As to this question the result of the analysis is that the chapter on Electronic Communications will be an important step towards facilitating trade in Electronic Communications services. At the same time some regulatory convergence will take place, but this convergence will not lead to a (full) harmonization of regulations. Rather the norm, also after TTIP negotiations will have been concluded successfully, will be mutual recognition of different regulatory regimes. Different regulations being the optimal policy response in different market settings will continue to exist. Moreover, it is very unlikely that such regulatory principles for the Electronic Communications sector are a vehicle for a race to the bottom in levels of consumer protection.}, language = {en} } @inproceedings{StaatDuong2016, author = {Staat, Manfred and Duong, Minh Tuan}, title = {Smoothed Finite Element Methods for Nonlinear Solid Mechanics Problems: 2D and 3D Case Studies}, series = {Proceedings of the National Science and Technology Conference on Mechanical - Transportation Engineering (NSCMET 2016), 13th October 2016, Hanoi, Vietnam, Vol.2}, booktitle = {Proceedings of the National Science and Technology Conference on Mechanical - Transportation Engineering (NSCMET 2016), 13th October 2016, Hanoi, Vietnam, Vol.2}, pages = {440 -- 445}, year = {2016}, abstract = {The Smoothed Finite Element Method (SFEM) is presented as an edge-based and a facebased techniques for 2D and 3D boundary value problems, respectively. SFEMs avoid shortcomings of the standard Finite Element Method (FEM) with lower order elements such as overly stiff behavior, poor stress solution, and locking effects. Based on the idea of averaging spatially the standard strain field of the FEM over so-called smoothing domains SFEM calculates the stiffness matrix for the same number of degrees of freedom (DOFs) as those of the FEM. However, the SFEMs significantly improve accuracy and convergence even for distorted meshes and/or nearly incompressible materials. Numerical results of the SFEMs for a cardiac tissue membrane (thin plate inflation) and an artery (tension of 3D tube) show clearly their advantageous properties in improving accuracy particularly for the distorted meshes and avoiding shear locking effects.}, language = {en} } @inproceedings{DuongJungFrotscheretal.2016, author = {Duong, Minh Tuan and Jung, Alexander and Frotscher, Ralf and Staat, Manfred}, title = {A 3D electromechanical FEM-based model for cardiac tissue}, series = {ECCOMAS Congress 2016, VII European Congress on Computational Methods in Applied Sciences and Engineering. Crete Island, Greece, 5-10 June 2016}, booktitle = {ECCOMAS Congress 2016, VII European Congress on Computational Methods in Applied Sciences and Engineering. Crete Island, Greece, 5-10 June 2016}, editor = {Papadrakakis, M.}, pages = {13 S.}, year = {2016}, language = {en} } @inproceedings{ButenwegKleemannAltayetal.2013, author = {Butenweg, Christoph and Kleemann, Anne and Altay, Okyay and Renault, Philippe}, title = {Simulation of impact-loads on reinforced concrete structural elements}, series = {22nd International Conference on Structural Mechanics in Reactor Technology 2013 : (SMiRT 22) ; San Francisco, California, USA, 18 - 23 August 2013}, booktitle = {22nd International Conference on Structural Mechanics in Reactor Technology 2013 : (SMiRT 22) ; San Francisco, California, USA, 18 - 23 August 2013}, organization = {International Conference on Structural Mechanics in Reactor Technology, SMIRT <22, 2013, San Francisco, Calif.>}, pages = {1 -- 10}, year = {2013}, language = {en} } @inproceedings{ButenwegRosinKubalski2013, author = {Butenweg, Christoph and Rosin, Julia and Kubalski, Thomas}, title = {Seismic response of conventional and base-isolated liquid storage tanks}, series = {International Conference on Earthquake Engineering : 29.-31.05.2013, Skopje, Mazedonien}, booktitle = {International Conference on Earthquake Engineering : 29.-31.05.2013, Skopje, Mazedonien}, organization = {International Conference on Earthquake Engineering <2013, Skopje>}, pages = {1 -- 8}, year = {2013}, language = {en} } @inproceedings{GellertNordaButenweg2008, author = {Gellert, Christoph and Norda, Hannah and Butenweg, Christoph}, title = {Nonlinear behaviour of masonry under cyclic loading}, series = {7th European Conference on Structural Dynamics, EURODYN 2008 : 7-9 July 2008, Southampton}, booktitle = {7th European Conference on Structural Dynamics, EURODYN 2008 : 7-9 July 2008, Southampton}, organization = {European Conference on Structural Dynamics, EURODYN <7, 2008, Southampton>}, pages = {1 -- 12}, year = {2008}, language = {en} } @inproceedings{RenaultButenweg2005, author = {Renault, Philippe and Butenweg, Christoph}, title = {Seismic vulnerability assessment of bridges}, series = {First Munich Bridge Assessment Conference, MBAC 2005 : Munich, 20.-25. June 2005}, booktitle = {First Munich Bridge Assessment Conference, MBAC 2005 : Munich, 20.-25. June 2005}, organization = {Munich Bridge Assessment Conference <1, 2005>}, pages = {1 -- 16}, year = {2005}, language = {en} } @inproceedings{ButenwegKuhlmannLopezetal.2003, author = {Butenweg, Christoph and Kuhlmann, Winfried and Lopez, M. and Fernandez, S.}, title = {Seismic vulnerability assessment of the Aachen Cathedral based on measurements and numerical simulations}, series = {International Conference on Earthquake Engineering to mark 40 years from Catastrophic 1963 Skopje Earthquake, Skopje 2003}, booktitle = {International Conference on Earthquake Engineering to mark 40 years from Catastrophic 1963 Skopje Earthquake, Skopje 2003}, organization = {International conference in earthquake engineering to mark 40 years from catastrophic 1963 Skopje earthquake <2003, Skopje>}, pages = {1 -- 8}, year = {2003}, language = {en} } @inproceedings{ChudobaButenwegKuhlmann2002, author = {Chudoba, Rostislav and Butenweg, Christoph and Kuhlmann, Wolfram}, title = {Technical information system for collaborative material research}, series = {Sixth International Conference on Computational Structures Technology : [Prague, Czech Republic, 4 - 6 September 2002]}, booktitle = {Sixth International Conference on Computational Structures Technology : [Prague, Czech Republic, 4 - 6 September 2002]}, organization = {International Conference on Computational Structures Technology <6, 2002, Prag>}, pages = {1 -- 11}, year = {2002}, language = {en} } @inproceedings{DalguerRenaultChurilovetal.2016, author = {Dalguer, Luis A. and Renault, Philippe and Churilov, Sergey and Butenweg, Christoph}, title = {Evaluation of fragility curves for a three-storey-reinforced-concrete mock-up of SMART 2013 project}, series = {Transactions, SMiRT-23 : 23rd Conference on Structural Mechanics in Reactor Technology : Manchester, United Kingdom - August 10-14, 2015}, booktitle = {Transactions, SMiRT-23 : 23rd Conference on Structural Mechanics in Reactor Technology : Manchester, United Kingdom - August 10-14, 2015}, organization = {Conference on Structural Mechanics in Reactor Technology <23, 2015, Manchester>}, pages = {1 -- 9}, year = {2016}, language = {en} } @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{BooysenMathewKnoxetal.2015, author = {Booysen, Tracy and Mathew, Thomas and Knox, Greig and Fong, W. K. and St{\"u}ttgen, Marcel and Ferrein, Alexander and Steinbauer, Gerald}, title = {The Scarab Project}, series = {ICRA 2015 Developing Countries Forum}, booktitle = {ICRA 2015 Developing Countries Forum}, pages = {3 S.}, year = {2015}, abstract = {Urban Search and Rescue (USAR) is an active research field in the robotics community. Despite recent advances for many open research questions, these kind of systems are not widely used in real rescue missions. One reason is that such systems are complex and not (yet) very reliable; another is that one has to be an robotic expert to run such a system. Moreover, available rescue robots are very expensive and the benefits of using them are still limited. In this paper, we present the Scarab robot, an alternative design for a USAR robot. The robot is light weight, humanpackable and its primary purpose is that of extending the rescuer's capability to sense the disaster site. The idea is that a responder throws the robot to a certain spot. The robot survives the impact with the ground and relays sensor data such as camera images or thermal images to the responder's hand-held control unit from which the robot can be remotely controlled.}, language = {en} } @inproceedings{StopforthFerreinSteinbauer2015, author = {Stopforth, Riaan and Ferrein, Alexander and Steinbauer, Gerald}, title = {Europe and South African collaboration on the Mechatronics and Robotics systems as part of the SA Robotics Center}, series = {ICRA 2015 Developing Countries Forum}, booktitle = {ICRA 2015 Developing Countries Forum}, pages = {3 S.}, year = {2015}, abstract = {Mechatronics consist of the integration of mechanical engineering, electronic integration and computer science/ engineering. These broad fields are essential for robotic systems, yet it makes it difficult for the researchers to specialize and be experts in all these fields. Collaboration between researchers allow for the integration of experience and specialization, to allow optimized systems. Collaboration between the European countries and South Africa is critical, as each country has different resources available, which the other countries might not have. Applications with the need for approval of any restrictions, can also be obtained easier in some countries compared to others, thus preventing the delays of research. Some problems that have been experienced are discussed, with the Robotics Center of South Africa as a possible solution.}, language = {en} } @inproceedings{NiemuellerFerreinReuteretal.2015, author = {Niemueller, Tim and Ferrein, Alexander and Reuter, Sebastian and Jeschke, Sabina and Lakemeyer, Gerhard}, title = {The RoboCup Logistics League as a Holistic Multi-Robot Smart Factory Benchmark}, series = {Proceedings of the IROS 2015 Open forum on evaluation of results, replication of experiments and benchmarking in robotics research}, booktitle = {Proceedings of the IROS 2015 Open forum on evaluation of results, replication of experiments and benchmarking in robotics research}, pages = {3 S.}, year = {2015}, abstract = {With autonomous mobile robots receiving increased attention in industrial contexts, the need for benchmarks becomes more and more an urgent matter. The RoboCup Logistics League (RCLL) is one specific industry-inspired scenario focusing on production logistics within a Smart Factory. In this paper, we describe how the RCLL allows to assess the performance of a group of robots within the scenario as a whole, focusing specifically on the coordination and cooperation strategies and the methods and components to achieve them. We report on recent efforts to analyze performance of teams in 2014 to understand the implications of the current grading scheme, and derived criteria and metrics for performance assessment based on Key Performance Indicators (KPI) adapted from classic factory evaluation. We reflect on differences and compatibility towards RoCKIn, a recent major benchmarking European project.}, language = {en} } @inproceedings{BuehlerLeandroBungetal.2015, author = {B{\"u}hler, P. and Leandro, J. and Bung, Daniel B. and Lopes, P. and Carvalho, R.}, title = {Measuring void fraction of a stepped spillway with non-intrusive methods using different image resolutions}, series = {2nd International Workshop on Hydraulic Structures : Data Validation : Coimbra, Portugal, 8-9 May 2015}, booktitle = {2nd International Workshop on Hydraulic Structures : Data Validation : Coimbra, Portugal, 8-9 May 2015}, organization = {International Workshop on Hydraulic Structures : Data Validation <2, 2015, Coimbra>}, pages = {1 -- 8}, year = {2015}, language = {en} }