@inproceedings{GrundmannBauerBieleetal.2018, author = {Grundmann, Jan Thimo and Bauer, Waldemar and Biele, Jens and Boden, Ralf and Ceriotti, Matteo and Cordero, Federico and Dachwald, Bernd and Dumont, Etienne and Grimm, Christian D. and Herč{\´i}k, David and Ho, Tra-Mi and Jahnke, Rico and Koch, Aaron D and Koncz, Alexander and Krause, Christian and Lange, Caroline and Lichtenheldt, Roy and Maiwald, Volker and Mikschl, Tobias and Mikulz, Eugen and Montenegro, Sergio and Pelivan, Ivanka and Peloni, Alessandro and Quantius, Dominik and Reershemius, Siebo and Renger, Thomas and Riemann, Johannes 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 Tardivel, Simon and T{\´o}th, Norbert and Wejmo, Elisabet and Wolff, Friederike and Ziach, Christian}, title = {Small spacecraft based multiple near-earth asteroid rendezvous and landing with near-term solar sails and 'Now-Term 'technologies}, series = {69 th International Astronautical Congress (IAC)}, booktitle = {69 th International Astronautical Congress (IAC)}, pages = {1 -- 18}, year = {2018}, abstract = {Physical interaction with small solar system bodies (SSSB) is the next step in planetary science, planetary in-situ resource utilization (ISRU), and planetary defense (PD). It requires a broader understanding of the surface properties of the target objects, with particular interest focused on those near Earth. Knowledge of composition, multi-scale surface structure, thermal response, and interior structure is required to design, validate and operate missions addressing these three fields. The current level of understanding is occasionally simplified into the phrase, "If you've seen one asteroid, you've seen one asteroid", meaning that the in-situ characterization of SSSBs has yet to cross the threshold towards a robust and stable scheme of classification. This would enable generic features in spacecraft design, particularly for ISRU and science missions. Currently, it is necessary to characterize any potential target object sufficiently by a dedicated pre-cursor mission to design the mission which then interacts with the object in a complex fashion. To open up strategic approaches, much broader in-depth characterization of potential target objects would be highly desirable. In SSSB science missions, MASCOT-like nano-landers and instrument carriers which integrate at the instrument level to their mothership have met interest. By its size, MASCOT is compatible with small interplanetary missions. The DLR-ESTEC Gossamer Roadmap Science Working Groups' studies identified Multiple Near-Earth asteroid (NEA) Rendezvous (MNR) as one of the space science missions only feasible with solar sail propulsion. The Solar Polar Orbiter (SPO) study showed the ability to access any inclination, theDisplaced-L1 (DL1) mission operates close to Earth, where objects of interest to PD and for ISRU reside. Other studies outline the unique capability of solar sails to provide access to all SSSB, at least within the orbit of Jupiter, and significant progress has been made to explore the performance envelope of near-term solar sails for MNR. However, it is difficult for sailcraft to interact physically with a SSSB. We expand and extend the philosophy of the recently qualified DLR Gossamer solar sail deployment technology using efficient multiple sub-spacecraft integration to also include landers for one-way in-situ investigations and sample-return missions by synergetic integration and operation of sail and lander. The MASCOT design concept and its characteristic features have created an ideal counterpart for thisand has already been adapted to the needs of the AIM spacecraft, former part of the NASA-ESA AIDA missionDesigning the 69th International Astronautical Congress (IAC), Bremen, Germany, 1-5 October 2018. IAC-18-F1.2.3 Page 2 of 17 combined spacecraft for piggy-back launch accommodation enables low-cost massively parallel access to the NEA population.}, language = {en} } @inproceedings{AnicPenavaGuljasetal.2018, author = {Anic, Filip and Penava, Davorin and Guljas, Ivica and Sarhosis, Vasilis and Abrahamczyk, Lars and Butenweg, Christoph}, title = {The Effect of Openings on Out-of-Plane Capacity of Masonry Infilled Reinforced Concrete Frames}, series = {16th European Conference on Earthquake Engineering, Thessaloniki, 18-21 June, 2018}, booktitle = {16th European Conference on Earthquake Engineering, Thessaloniki, 18-21 June, 2018}, pages = {1 -- 11}, year = {2018}, language = {en} } @article{MichelButenwegKinkel2018, author = {Michel, Philipp and Butenweg, Christoph and Kinkel, Sven}, title = {Pile-grid foundations of onshore wind turbines considering soil-structure-interaction under seismic loading}, series = {Soil Dynamics and Earthquake Engineering}, volume = {109}, journal = {Soil Dynamics and Earthquake Engineering}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0267-7261}, doi = {10.1016/j.soildyn.2018.03.009}, pages = {299 -- 311}, year = {2018}, abstract = {In recent years, many onshore wind turbines are erected in seismic active regions and on soils with poor load bearing capacity, where pile grids are inevitable to transfer the loads into the ground. In this contribution, a realistic multi pile grid is designed to analyze the dynamics of a wind turbine tower including frequency dependent soil-structure-interaction. It turns out that different foundations on varying soil configurations heavily influence the vibration response. While the vibration amplitude is mostly attenuated, certain unfavorable combinations of structure and soil parameters lead to amplification in the range of the system's natural frequencies. This testifies the need for overall dynamic analysis in the assessment of the dynamic stability and the holistic frequency tuning of the turbines.}, language = {en} } @article{RosinButenwegCacciatoreetal.2018, author = {Rosin, Julia and Butenweg, Christoph and Cacciatore, Pamela and Boesen, Niklas}, title = {Investigation of the seismic performance of modern masonry buildings during the Emilia Romagna earthquake series}, series = {Mauerwerk}, volume = {22}, journal = {Mauerwerk}, number = {4}, publisher = {Ernst \& Sohn}, address = {Berlin}, issn = {1437-1022}, doi = {10.1002/dama.201800013}, pages = {238 -- 250}, year = {2018}, abstract = {The article presents the investigation of the seismic behaviour of a modern URM building located in the municipality of Finale Emilia in province of Modena, Northern Italy. The building is situated in the centre of the series of the 2012 Northern Italy earthquakes and has not suffered any damage during the earthquake series in 2012. The observed earthquake resistance of the building is compared with predicted resistances based on linear and nonlinear design approaches according to Eurocode. Furthermore, probabilistic analyses based on nonlinear calculation models taking into account scattering of the most relevant input parameters are carried out to identify their influence to the results and to derive fragility curves.}, language = {en} } @inproceedings{GoettenHavermannBraunetal.2018, author = {G{\"o}tten, Falk and Havermann, Marc and Braun, Carsten and Gomez, Francisco and Bil, Cees}, title = {On the Applicability of Empirical Drag Estimation Methods for Unmanned Air Vehicle Design Read More: https://arc.aiaa.org/doi/10.2514/6.2018-3192}, series = {2018 Aviation Technology, Integration, and Operations Conference, AIAA AVIATION Forum}, booktitle = {2018 Aviation Technology, Integration, and Operations Conference, AIAA AVIATION Forum}, issn = {1533-385X}, doi = {10.2514/6.2018-3192}, pages = {Article 3192}, year = {2018}, language = {en} } @inproceedings{ValeroVogelSchmidtetal.2018, author = {Valero, Daniel and Vogel, Jochen and Schmidt, Daniel and Bung, Daniel Bernhard}, title = {Three-dimensional flow structure inside the cavity of a non-aerated stepped chute}, series = {7th IAHR International Symposium on Hydraulic Structures, Aachen, Germany, 15-18 May}, booktitle = {7th IAHR International Symposium on Hydraulic Structures, Aachen, Germany, 15-18 May}, isbn = {978-0-692-13277-7}, doi = {10.15142/T3GH17}, pages = {12 Seiten}, year = {2018}, language = {en} } @article{CiritsisHorbachStaatetal.2018, author = {Ciritsis, Alexander and Horbach, Andreas and Staat, Manfred and Kuhl, Christiane K. and Kraemer, Nils Andreas}, title = {Porosity and tissue integration of elastic mesh implants evaluated in vitro and in vivo}, series = {Journal of Biomedical Materials Research: Part B: Applied Biomaterials}, volume = {106}, journal = {Journal of Biomedical Materials Research: Part B: Applied Biomaterials}, number = {2}, publisher = {Wiley}, address = {New York, NY}, issn = {1552-4981}, doi = {10.1002/jbm.b.33877}, pages = {827 -- 833}, year = {2018}, abstract = {Purpose In vivo, a loss of mesh porosity triggers scar tissue formation and restricts functionality. The purpose of this study was to evaluate the properties and configuration changes as mesh deformation and mesh shrinkage of a soft mesh implant compared with a conventional stiff mesh implant in vitro and in a porcine model. Material and Methods Tensile tests and digital image correlation were used to determine the textile porosity for both mesh types in vitro. A group of three pigs each were treated with magnetic resonance imaging (MRI) visible conventional stiff polyvinylidene fluoride meshes (PVDF) or with soft thermoplastic polyurethane meshes (TPU) (FEG Textiltechnik mbH, Aachen, Germany), respectively. MRI was performed with a pneumoperitoneum at a pressure of 0 and 15 mmHg, which resulted in bulging of the abdomen. The mesh-induced signal voids were semiautomatically segmented and the mesh areas were determined. With the deformations assessed in both mesh types at both pressure conditions, the porosity change of the meshes after 8 weeks of ingrowth was calculated as an indicator of preserved elastic properties. The explanted specimens were examined histologically for the maturity of the scar (collagen I/III ratio). Results In TPU, the in vitro porosity increased constantly, in PVDF, a loss of porosity was observed under mild stresses. In vivo, the mean mesh areas of TPU were 206.8 cm2 (± 5.7 cm2) at 0 mmHg pneumoperitoneum and 274.6 cm2 (± 5.2 cm2) at 15 mmHg; for PVDF the mean areas were 205.5 cm2 (± 8.8 cm2) and 221.5 cm2 (± 11.8 cm2), respectively. The pneumoperitoneum-induced pressure increase resulted in a calculated porosity increase of 8.4\% for TPU and of 1.2\% for PVDF. The mean collagen I/III ratio was 8.7 (± 0.5) for TPU and 4.7 (± 0.7) for PVDF. Conclusion The elastic properties of TPU mesh implants result in improved tissue integration compared to conventional PVDF meshes, and they adapt more efficiently to the abdominal wall. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 827-833, 2018.}, language = {en} } @inproceedings{TranMatthiesStavroulakisetal.2018, author = {Tran, Ngoc Trinh and Matthies, Hermann G. and Stavroulakis, Georgios Eleftherios and Staat, Manfred}, title = {Direct plastic structural design by chance constrained programming}, 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 = {12 Seiten}, year = {2018}, abstract = {We propose a stochastic programming method to analyse limit and shakedown of structures under random strength with lognormal distribution. In this investigation a dual chance constrained programming algorithm is developed to calculate simultaneously both the upper and lower bounds of the plastic collapse limit or the shakedown limit. The edge-based smoothed finite element method (ES-FEM) using three-node linear triangular elements is used.}, language = {en} } @incollection{ArtmannMeruvuKizildagetal.2018, author = {Artmann, Gerhard and Meruvu, Haritha and Kizildag, Sefa and Temiz Artmann, Ayseg{\"u}l}, title = {Functional Toxicology and Pharmacology Test of Cell Induced Mechanical Tensile Stress in 2D and 3D Tissue Cultures}, series = {Biological, Physical and Technical Basics of Cell Engineering}, booktitle = {Biological, Physical and Technical Basics of Cell Engineering}, editor = {Artmann, Gerhard and Temiz Artmann, Ayseg{\"u}l and Zhubanova, Azhar A. and Digel, Ilya}, publisher = {Springer}, address = {Singapore}, isbn = {978-981-10-7904-7}, doi = {10.1007/978-981-10-7904-7_7}, pages = {157 -- 192}, year = {2018}, abstract = {Mechanical forces/tensile stresses are critical determinants of cellular growth, differentiation and migration patterns in health and disease. The innovative "CellDrum technology" was designed for measuring mechanical tensile stress of cultured cell monolayers/thin tissue constructs routinely. These are cultivated on very thin silicone membranes in the so-called CellDrum. The cell layers adhere firmly to the membrane and thus transmit the cell forces generated. A CellDrum consists of a cylinder which is sealed from below with a 4 μm thick, biocompatible, functionalized silicone membrane. The weight of cell culture medium bulbs the membrane out downwards. Membrane indentation is measured. When cells contract due to drug action, membrane, cells and medium are lifted upwards. The induced indentation changes allow for lateral drug induced mechanical tension quantification of the micro-tissues. With hiPS-induced (human) Cardiomyocytes (CM) the CellDrum opens new perspectives of individualized cardiac drug testing. Here, monolayers of self-beating hiPS-CMs were grown in CellDrums. Rhythmic contractions of the hiPS-cells induce membrane up-and-down deflections. The recorded cycles allow for single beat amplitude, single beat duration, integration of the single beat amplitude over the beat time and frequency analysis. Dose effects of agonists and antagonists acting on Ca2+ channels were sensitively and highly reproducibly observed. Data were consistent with published reference data as far as they were available. The combination of the CellDrum technology with hiPS-Cardiomyocytes offers a fast, facile and precise system for pharmacological and toxicological studies. It allows new preclinical basic as well as applied research in pharmacolgy and toxicology.}, 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} }