@inproceedings{ReindlButenwegKubalski2011, author = {Reindl, Lukas and Butenweg, Christoph and Kubalski, Thomas}, title = {Numerical simulation of unreinforced masonry walls subject to dynamic out-of-plane loading}, series = {COMPDYN 2011 : ECCOMAS Thematic Conference ; Proceedings of the 3rd International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering ; 25-28 May, 2011, Corfu, Greece / Eds.: M. Papadrakakis ...}, booktitle = {COMPDYN 2011 : ECCOMAS Thematic Conference ; Proceedings of the 3rd International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering ; 25-28 May, 2011, Corfu, Greece / Eds.: M. Papadrakakis ...}, publisher = {National Technical Univ. of Athens}, address = {Athen}, organization = {COMPDYN <2011, Corfu>}, isbn = {978-960-99994-0-3}, pages = {1 -- 10}, year = {2011}, language = {en} } @inproceedings{ParkElDaibButenwegetal.2011, author = {Park, Jin and El-Daib, Khaled and Butenweg, Christoph and Gellert, Christoph}, title = {A novel macroelement approach for masonry walls}, series = {Proceedings of the 8th International Conference on Structural Dynamics, EURODYN 2011 : Leuven, Belgium, 4 - 6 July 2011 / Katholieke Universiteit Leuven, ... G. De Roeck ... (eds)}, booktitle = {Proceedings of the 8th International Conference on Structural Dynamics, EURODYN 2011 : Leuven, Belgium, 4 - 6 July 2011 / Katholieke Universiteit Leuven, ... G. De Roeck ... (eds)}, publisher = {K. U. Leuven, Dep. of Civil Engineering}, address = {Leuven}, organization = {International Conference on Structural Dynamics, EURODYN <8, 2011, Leuven>}, isbn = {978-90-76019-31-4}, pages = {3281 -- 3286}, year = {2011}, language = {en} } @inproceedings{TaddeiReindlParketal.2011, author = {Taddei, Francesca and Reindl, Lukas and Park, Jin and Butenweg, Christoph and Karadogan, Faruk}, title = {Numerical investigation of AAC wall panels based on the damage plasticity constitutive law}, series = {Cement, Wapno, Beton ; 2011, 7, Special issue: 5th International Conference on Autoclaved Aerated Concrete 'Securing a sustainable future' to be held at Bydgoszcz to celebrate 60 years of AAC experience in Poland, Bydgoszcz, September 14-17, 2011}, booktitle = {Cement, Wapno, Beton ; 2011, 7, Special issue: 5th International Conference on Autoclaved Aerated Concrete 'Securing a sustainable future' to be held at Bydgoszcz to celebrate 60 years of AAC experience in Poland, Bydgoszcz, September 14-17, 2011}, publisher = {Stowarzyszenie Producent{\´o}w Cementu i Wapna}, address = {Krakow}, organization = {International Conference on Autoclaved Aerated Concrete 'Securing a sustainable future' <5, 2011, Bydgoszcz>}, issn = {1425-8129}, pages = {86 -- 91}, year = {2011}, language = {en} } @inproceedings{ReindlParkNordaetal.2010, author = {Reindl, Lukas and Park, Jin and Norda, Hannah and Butenweg, Christoph}, title = {Seismic design of masonry walls subject to out-of-plane bending}, series = {Proceedings of the Tenth International Conference on Computational Structures Technology : Valencia, Spain, 14 - 17 September 2010 / organised in association with: Universidad Politecnica de Valencia ... Ed. by B. H. V. Topping ...}, booktitle = {Proceedings of the Tenth International Conference on Computational Structures Technology : Valencia, Spain, 14 - 17 September 2010 / organised in association with: Universidad Politecnica de Valencia ... Ed. by B. H. V. Topping ...}, publisher = {Civil-Comp Press}, address = {Kippen}, organization = {International Conference on Computational Structures Technology <10, 2010, Valencia>}, isbn = {978-1-905088-36-2}, doi = {10.4203/ccp.93.348}, pages = {Paper 348}, year = {2010}, language = {en} } @inproceedings{GoemmelKraemerButenwegetal.2005, author = {G{\"o}mmel, Andreas and Kr{\"a}mer, Sebastian and Butenweg, Christoph and Kob, Malte}, title = {A combined FE and multiple-mass model for numerical simulation of phonatory maneuvers}, series = {Proceedings / Forum Acusticum, Budapest, 29 Aug - 2 Sep, 2005 : [Acoustics: science and technology for knowledge based society and healthy environment] / ed. by: F{\"u}l{\"o}p Augusztinovicz ...}, booktitle = {Proceedings / Forum Acusticum, Budapest, 29 Aug - 2 Sep, 2005 : [Acoustics: science and technology for knowledge based society and healthy environment] / ed. by: F{\"u}l{\"o}p Augusztinovicz ...}, publisher = {OPAKFI Tud. Egyes{\"u}let}, address = {Budapest}, organization = {Forum Acusticum <4, 2005, Budapest>}, isbn = {978-963-8241-68-9}, pages = {2759 -- 2764}, year = {2005}, language = {en} } @inproceedings{GoemmelButenwegKob2005, author = {G{\"o}mmel, Andreas and Butenweg, Christoph and Kob, Malte}, title = {Towards a complete finite-element model of human phonation: modeling phonatory maneuvers}, series = {12th Workshop on the Finite Element Method in Biomedical Engineering, Biomechanics and Related Fields : Ulm, Germany, 20 - 21 July 2005 / University of Ulm, Department of Orthodontics ...}, booktitle = {12th Workshop on the Finite Element Method in Biomedical Engineering, Biomechanics and Related Fields : Ulm, Germany, 20 - 21 July 2005 / University of Ulm, Department of Orthodontics ...}, publisher = {Univ., Dep. of Orthodontics}, address = {Ulm}, organization = {Workshop on the Finite Element Method in Biomedical Engineering, Biomechanics and Related Fields <12, 2005, Ulm>}, isbn = {978-3-9806183-8-0}, pages = {1 CD-ROM}, year = {2005}, language = {en} } @inproceedings{ButenwegMistler2006, author = {Butenweg, Christoph and Mistler, Michael}, title = {Seismic resistance of unreinforced masonry buildings}, series = {Proceedings of the Eighth International Conference on Computational Structures Technology : [Las Palmas de Cran Canaria, 12-15 September 2006] / ed. by B. H. V. Topping ...}, booktitle = {Proceedings of the Eighth International Conference on Computational Structures Technology : [Las Palmas de Cran Canaria, 12-15 September 2006] / ed. by B. H. V. Topping ...}, publisher = {Civil-Comp Press}, address = {Stirling}, organization = {International Conference on Computational Structures Technology <8, 2006, Las Palmas>}, isbn = {1-905088-06-X}, doi = {10.4203/ccp.83.9}, pages = {Paper 9}, year = {2006}, language = {en} } @inproceedings{ButenwegGellertReindl2008, author = {Butenweg, Christoph and Gellert, Christoph and Reindl, Lukas}, title = {Capacity design of masonry buildings under cyclic loading}, series = {Seismic Risk : Earthquakes in North-Western Europe ; international colloquium ; Li{\`e}ge on 11 and 12 September 2008 / Belgian Seismic Group (BeSeiG). Ed.: T. Camlebeeck ...}, booktitle = {Seismic Risk : Earthquakes in North-Western Europe ; international colloquium ; Li{\`e}ge on 11 and 12 September 2008 / Belgian Seismic Group (BeSeiG). Ed.: T. Camlebeeck ...}, publisher = {Editions de l'Universit{\´e} de Li{\`e}ge}, address = {Li{\`e}ge}, organization = {Belgian Seismic Group}, isbn = {978-2-87456-063-7}, pages = {201 -- 208}, year = {2008}, language = {en} } @inproceedings{ButenwegGellert2008, author = {Butenweg, Christoph and Gellert, Christoph}, title = {Displacement based design of masonry structures}, series = {Proceedings of the 14th International Brick and Block Masonry Conference : (Incorporating the 8th Australasian Masonry Conference) : Sydney, Australia, 13.-20. February 2008 / ed. Mark Masia ...}, booktitle = {Proceedings of the 14th International Brick and Block Masonry Conference : (Incorporating the 8th Australasian Masonry Conference) : Sydney, Australia, 13.-20. February 2008 / ed. Mark Masia ...}, publisher = {University of Newcastle}, address = {Callaghan}, organization = {International Brick and Block Masonry Conference <14, 2008, Sydney>}, isbn = {978-19-2070-1-92-5}, pages = {1 -- 10}, year = {2008}, language = {en} } @inproceedings{KuhlmannButenwegLopezetal.2004, author = {Kuhlmann, Wolfram and Butenweg, Christoph and Lopez, Marijen and Fernandez, Sebastian}, title = {Seismic vulnerability assessment of the historic Aachen Cathedral}, series = {Conference proceedings / 13th World Conference on Earthquake Engineering [Vancouver, British Columbia, Canada, August 1 - 6, 2004] / [hosted by CAEE/ACGP, Canadian Association for Earthquake Engineering]}, booktitle = {Conference proceedings / 13th World Conference on Earthquake Engineering [Vancouver, British Columbia, Canada, August 1 - 6, 2004] / [hosted by CAEE/ACGP, Canadian Association for Earthquake Engineering]}, publisher = {CAEE}, address = {Vancouver}, organization = {World Conference on Earthquake Engineering <13, 2004, Vancouver>}, pages = {1 -- 14}, year = {2004}, language = {en} } @inproceedings{MeskourisButenwegMistleretal.2004, author = {Meskouris, Konstantin and Butenweg, Christoph and Mistler, Michael and Kuhlmann, Wolfram}, title = {Seismic behaviour of historic masonry buildings}, series = {7th National Congress on Mechanics : Chania, Crete, June 24 - 26, 2004 ; proceedings / ed. A. Kounadis ....}, booktitle = {7th National Congress on Mechanics : Chania, Crete, June 24 - 26, 2004 ; proceedings / ed. A. Kounadis ....}, publisher = {Hellenic Society for Theoretical and Applied Mechanics}, address = {Chania}, organization = {National Congress on Mechanics <7, 2004, Chania, Crete>}, pages = {47 -- 49}, year = {2004}, language = {en} } @inproceedings{EggertWeber2023, author = {Eggert, Mathias and Weber, Jannik}, title = {What drives the purchase decision in Instagram stores?}, series = {ECIS 2023 Research Papers}, booktitle = {ECIS 2023 Research Papers}, pages = {1 -- 17}, year = {2023}, abstract = {The popularity of social media and particularly Instagram grows steadily. People use the different platforms to share pictures as well as videos and to communicate with friends. The potential of social media platforms is also being used for marketing purposes and for selling products. While for Facebook and other online social media platforms the purchase decision factors are investigated several times, Instagram stores remain mainly unattended so far. The present research work closes this gap and sheds light into decisive factors for purchasing products offered in Instagram stores. A theoretical research model, which contains selected constructs that are assumed to have a significant influence on Instagram user´s purchase intention, is developed. The hypotheses are evaluated by applying structural equation modelling on survey data containing 127 relevant participants. The results of the study reveal that 'trust', 'personal recommendation', and 'usability' significantly influences user's buying intention in Instagram stores.}, language = {en} } @inproceedings{MarinkovicButenweg2020, author = {Marinkovic, Marko and Butenweg, Christoph}, title = {Seismic behaviour of RC frames with uncoupled masonry infills having two storeys or two bays}, series = {Brick and Block Masonry - From Historical to Sustainable Masonry. Proceedings of the 17th International Brick/Block Masonry Conference}, booktitle = {Brick and Block Masonry - From Historical to Sustainable Masonry. Proceedings of the 17th International Brick/Block Masonry Conference}, publisher = {CRC Press}, address = {London}, doi = {10.1201/9781003098508-72}, pages = {1 -- 7}, year = {2020}, abstract = {Reinforced concrete (RC) structures with masonry infills are widely used for several types of buildings all over the world. However, it is well known that traditional masonry infills constructed with rigid contact to the surrounding RC frame performed rather poor in past earthquakes. Masonry infills showed severe in-plane damages and failed in many cases under out-of-plane seismic loading. As the undesired interactions between frames and infills changes the load transfer on building level, complete collapses of buildings were observed. A possible solution is uncoupling of masonry infills to the frame to reduce the infill contribution activated by the frame deformation under horizontal loading. The paper presents numerical simulations on RC frames equipped with the innovative decoupling system INODIS. The system was developed within the European project INSYSME and allows an effective uncoupling of frame and infill. The simulations are carried out with a micro-modelling approach, which is able to predict the complex nonlinear behaviour resulting from the different materials and their interaction. Each brick is modelled individually and connected taking into account nonlinearity of a brick mortar interface. The calibration of the model is based on small specimen tests and experimental results for one bay one storey frame are used for the validation. The validated model is further used for parametric studies on two storey and two bay infilled frames. The response and change of the structural stiffness are analysed and compared to the traditionally infilled frame. The results confirm the effectiveness of the INODIS system with less damage and relatively low contribution of the infill at high drift levels. In contrast to the uncoupled system configurations, traditionally infilled frames experienced brittle failure at rather low drift levels.}, language = {en} } @inproceedings{MichelRosinButenwegetal.2020, author = {Michel, Philipp and Rosin, Julia and Butenweg, Christoph and Klinkel, Sven}, title = {Soil-dependent earthquake spectra in the analysis of liquid-storage-tanks on compliant soil}, series = {Seismic design of industrial facilities 2020}, booktitle = {Seismic design of industrial facilities 2020}, publisher = {Apprimus Verlag}, address = {Aachen}, isbn = {978-3-86359-729-0}, pages = {245 -- 254}, year = {2020}, abstract = {A further development of the Added-Mass-Method allows the combined representation of the effects of both soil-structure-interaction and fluid-structure interaction on a liquid-filled-tank in one model. This results in a practical method for describing the dynamic fluid pressure on the tank shell during joint movement. The fluid pressure is calculated on the basis of the tank's eigenform and the earthquake acceleration and represented by additional masses on the shell. The bearing on compliant ground is represented by replacement springs, which are calculated dependent on the local soil composition. The influence of the shear modulus of the compliant soil is clearly visible in the pressure curves and the stress distribution in the shell. The acceleration spectra are also dependent on soil stiffness. According to Eurocode-8 the acceleration spectra are determined for fixed soil-classes, instead of calculating the accelerations for each site in direct dependence on the soil composition. This leads to unrealistic sudden changes in the system's response. Therefore, earthquake spectra are calculated for different soil models in direct dependence of the shear modulus. Thus, both the acceleration spectra and the replacement springs match the soil composition. This enables a reasonable and consistent calculation of the system response for the actual conditions at each site.}, language = {en} } @inproceedings{MarkinkovicButenwegPaveseetal.2020, author = {Markinkovic, Marko and Butenweg, Christoph and Pavese, A. and Lanese, I. and Hoffmeister, B. and Pinkawa, M. and Vulcu, C. and Bursi, O. and Nardin, C. and Paolacci, F. and Quinci, G. and Fragiadakis, M. and Weber, F. and Huber, P. and Renault, P. and G{\"u}ndel, M. and Dyke, S. and Ciucci, M. and Marino, A.}, title = {Investigation of the seismic behaviour of structural and nonstructural components in industrial facilities by means of shaking table tests}, series = {Seismic design of industrial facilities 2020}, booktitle = {Seismic design of industrial facilities 2020}, publisher = {Apprimus Verlag}, address = {Aachen}, isbn = {978-3-86359-729-0}, pages = {159 -- 172}, year = {2020}, language = {en} } @inproceedings{CacciatoreButenweg2020, author = {Cacciatore, Pamela and Butenweg, Christoph}, title = {Seismic safety of cylindrical granular material steel silos under seismic loading}, series = {Seismic design of industrial facilities 2020}, booktitle = {Seismic design of industrial facilities 2020}, publisher = {Apprimus Verlag}, address = {Aachen}, isbn = {978-3-86359-729-0}, pages = {231 -- 244}, year = {2020}, language = {en} } @inproceedings{GrundmannBauerBodenetal.2019, author = {Grundmann, Jan Thimo and Bauer, Waldemar and Boden, Ralf Christian and Ceriotti, Matteo and Cordero, Federico and Dachwald, Bernd and Dumont, Etienne and Grimm, Christian D. and Hercik, D. and Herique, A. and Ho, Tra-Mi and Jahnke, Rico and Kofman, Wlodek and Lange, Caroline and Lichtenheldt, Roy and McInnes, Colin R. and Mikschl, Tobias and Montenegro, Sergio and Moore, Iain and Pelivan, Ivanka and Peloni, Alessandro and Plettenmeier, Dirk and Quantius, Dominik and Reershemius, Siebo and Renger, Thomas and Riemann, Johannes and Rogez, Yves and Ruffer, Michael and Sasaki, Kaname and Schmitz, Nicole and Seboldt, Wolfgang and Seefeldt, Patric and Spietz, Peter and Spr{\"o}witz, Tom and Sznajder, Maciej and Toth, Norbert and Viavattene, Giulia and Wejmo, Elisabet and Wolff, Friederike and Ziach, Christian}, title = {Responsive exploration and asteroid characterization through integrated solar sail and lander development using small spacecraft technologies}, series = {IAA Planetary Defense Conference}, booktitle = {IAA Planetary Defense Conference}, year = {2019}, abstract = {In parallel to the evolution of the Planetary Defense Conference, the exploration of small solar system bodies has advanced from fast fly-bys on the sidelines of missions to the planets to the implementation of dedicated sample-return and in-situ analysis missions. Spacecraft of all sizes have landed, touch-and-go sampled, been gently beached, or impacted at hypervelocity on asteroid and comet surfaces. More have flown by close enough to image their surfaces in detail or sample their immediate environment, often as part of an extended or re-purposed mission. And finally, full-scale planetary defense experiment missions are in the making. Highly efficient low-thrust propulsion is increasingly applied beyond commercial use also in mainstream and flagship science missions, in combination with gravity assist propulsion. Another development in the same years is the growth of small spacecraft solutions, not in size but in numbers and individual capabilities. The on-going NASA OSIRIS-REx and JAXA HAYABUSA2 missions exemplify the trend as well as the upcoming NEA SCOUT mission or the landers MINERVA-II and MASCOT recently deployed on Ryugu. We outline likely as well as possible and efficient routes of continuation of all these developments towards a propellant-less and highly efficient class of spacecraft for small solar system body exploration: small spacecraft solar sails designed for carefree handling and equipped with carried landers and application modules, for all asteroid user communities -planetary science, planetary defence, and in-situ resource utilization. This projection builds on the experience gained in the development of deployable membrane structures leading up to the successful ground deployment test of a (20 m)² solar sail at DLR Cologne and in the 20 years since. It draws on the background of extensive trajectory optimization studies, the qualified technology of the DLR GOSSAMER-1 deployment demonstrator, and the MASCOT asteroid lander. These enable 'now-term' as well as near-term hardware solutions, and thus responsive fast-paced development. Mission types directly applicable to planetary defense include: single and Multiple NEA Rendezvous ((M)NR) for mitigation precursor, target monitoring and deflection follow-up tasks; sail-propelled head-on retrograde kinetic impactors (RKI) for mitigation; and deployable membrane based methods to modify the asteroid's properties or interact with it. The DLR-ESTEC GOSSAMER Roadmap initiated studies of missions uniquely feasible with solar sails such as Displaced L1 (DL1) space weather advance warning and monitoring and Solar Polar Orbiter (SPO) delivery which demonstrate the capability of near-term solar sails to achieve NEA rendezvous in any kind of orbit, from Earth-coorbital to extremely inclined and even retrograde orbits. For those mission types using separable payloads, such as SPO, (M)NR and RKI, design concepts can be derived from the separable Boom Sail Deployment Units characteristic of DLR GOSSAMER solar sail technology, nanolanders like MASCOT, or microlanders like the JAXA-DLR Jupiter Trojan Asteroid Lander for the OKEANOS mission which can shuttle from the sail to the asteroids visited and enable multiple NEA sample-return missions. These are an ideal match for solar sails in micro-spacecraft format whose launch configurations are compatible with ESPA and ASAP secondary payload platforms.}, language = {en} } @inproceedings{MoehrenBergmannJanseretal.2023, author = {M{\"o}hren, Felix and Bergmann, Ole and Janser, Frank and Braun, Carsten}, title = {On the determination of harmonic propeller loads}, series = {AIAA SCITECH 2023 Forum}, booktitle = {AIAA SCITECH 2023 Forum}, publisher = {AIAA}, doi = {10.2514/6.2023-2404}, pages = {12 Seiten}, year = {2023}, abstract = {Dynamic loads significantly impact the structural design of propeller blades due to fatigue and static strength. Since propellers are elastic structures, deformations and aerodynamic loads are coupled. In the past, propeller manufacturers established procedures to determine unsteady aerodynamic loads and the structural response with analytical steady-state calculations. According to the approach, aeroelastic coupling primarily consists of torsional deformations. They neglect bending deformations, deformation velocities, and inertia terms. This paper validates the assumptions above for a General Aviation propeller and a lift propeller for urban air mobility or large cargo drones. Fully coupled reduced-order simulations determine the dynamic loads in the time domain. A quasi-steady blade element momentum approach transfers loads to one-dimensional finite beam elements. The simulation results are in relatively good agreement with the analytical method for the General Aviation propeller but show increasing errors for the slender lift propeller. The analytical approach is modified to consider the induced velocities. Still, inertia and velocity proportional terms play a significant role for the lift propeller due to increased elasticity. The assumption that only torsional deformations significantly impact the dynamic loads of propellers is not valid. Adequate determination of dynamic loads of such designs requires coupled aeroelastic simulations or advanced analytical procedures.}, language = {en} } @inproceedings{Dachwald2005, author = {Dachwald, Bernd}, title = {Global optimization of low-thrust space missions using evolutionary neurocontrol}, series = {Proceedings of the international workshop on global optimization}, booktitle = {Proceedings of the international workshop on global optimization}, pages = {85 -- 90}, year = {2005}, abstract = {Low-thrust space propulsion systems enable flexible high-energy deep space missions, but the design and optimization of the interplanetary transfer trajectory is usually difficult. It involves much experience and expert knowledge because the convergence behavior of traditional local trajectory optimization methods depends strongly on an adequate initial guess. Within this extended abstract, evolutionary neurocontrol, a method that fuses artificial neural networks and evolutionary algorithms, is proposed as a smart global method for low-thrust trajectory optimization. It does not require an initial guess. The implementation of evolutionary neurocontrol is detailed and its performance is shown for an exemplary mission.}, language = {en} } @inproceedings{SchartnerLoebDachwaldetal.2009, author = {Schartner, Karl-Heinz and Loeb, H. W. and Dachwald, Bernd and Ohndorf, Andreas}, title = {Perspectives of electric propulsion for outer planetary and deep space missions}, series = {European Planetary Science Congress 2009}, booktitle = {European Planetary Science Congress 2009}, pages = {416 -- 416}, year = {2009}, abstract = {Solar-electric propulsion (SEP) is superior with respect to payload capacity, flight time and flexible launch window to the conventional interplanetary transfer method using chemical propulsion combined with gravity assists. This fact results from the large exhaust velocities of electric low-thrust propulsion and is favourable also for missions to the giant planets, Kuiper-belt objects and even for a heliopause probe (IHP) as shown in three studies by the authors funded by DLR. They dealt with a lander for Europa and a sample return mission from a mainbelt asteroid [1], with the TANDEM mission [2]; the third recent one investigates electric propulsion for the transfer to the edge of the solar system. All studies are based on triple-junction solar arrays, on rf-ion thrusters of the qualified RIT-22 type and they use the intelligent trajectory optimization program InTrance [3].}, language = {en} }