TY - JOUR A1 - Anzt, H. A1 - Bach, F. A1 - Druskat, S. A1 - Löffler, F. A1 - Loewe, A. A1 - Renard, B. Y. A1 - Seemann, G. A1 - Struck, A. A1 - Achhammer, E. A1 - Aggarwal, P. A1 - Appel, F. A1 - Bader, M. A1 - Brusch, L. A1 - Busse, C. A1 - Chourdakis, G. A1 - Dabrowski, P. W. A1 - Ebert, P. A1 - Flemisch, B. A1 - Friedl, S. A1 - Fritzsch, B. A1 - Funk, M. D. A1 - Gast, V. A1 - Goth, F. A1 - Grad, J. A1 - Hegewald, J. A1 - Hermann, S. A1 - Hohmann, F. A1 - Janosch, S. A1 - Kutra, D. A1 - Linxweiler, J. A1 - Muth, Thilo A1 - Peters-Kottig, W. A1 - Rack, F. A1 - Raters, F. H. C. A1 - Rave, S. A1 - Reina, G. A1 - Reißig, M. A1 - Ropinski, T. A1 - Schaarschmidt, J. A1 - Seibold, H. A1 - Thiele, J. P. A1 - Uekermann, B. A1 - Unger, S. A1 - Weeber, R. T1 - An environment for sustainable research software in Germany and beyond: current state, open challenges, and call for action N2 - Research software has become a central asset in academic research. It optimizes existing and enables new research methods, implements and embeds research knowledge, and constitutes an essential research product in itself. Research software must be sustainable in order to understand, replicate, reproduce, and build upon existing research or conduct new research effectively. In other words, software must be available, discoverable, usable, and adaptable to new needs, both now and in the future. Research software therefore requires an environment that supports sustainability. Hence, a change is needed in the way research software development and maintenance are currently motivated, incentivized, funded, structurally and infrastructurally supported, and legally treated. Failing to do so will threaten the quality and validity of research. In this paper, we identify challenges for research software sustainability in Germany and beyond, in terms of motivation, selection, research software engineering personnel, funding, infrastructure, and legal aspects. Besides researchers, we specifically address political and academic decision-makers to increase awareness of the importance and needs of sustainable research software practices. In particular, we recommend strategies and measures to create an environment for sustainable research software, with the ultimate goal to ensure that software-driven research is valid, reproducible and sustainable, and that software is recognized as a first class citizen in research. This paper is the outcome of two workshops run in Germany in 2019, at deRSE19 - the first International Conference of Research Software Engineers in Germany - and a dedicated DFG-supported follow-up workshop in Berlin. KW - Research Software KW - Sustainable Software Development KW - Academic Software KW - Software Infrastructure KW - Software Training KW - Software Licensing PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-522029 DO - https://doi.org/10.12688/f1000research.23224.2 VL - 9 SP - 1 EP - 35 AN - OPUS4-52202 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ghazanfari, M. R. A1 - Vittadello, L. A1 - Al-Sabbagh, Dominik A1 - Santhosh, A. A1 - Frankcom, C. A1 - Fuß, F. A1 - von Randow, C. A. A1 - Siemensmeyer, K. A1 - Vrijmoed, J. C. A1 - Emmerling, Franziska A1 - Jerabek, P. A1 - Irmlau, M. A1 - Thiele, G. T1 - Remarkable Infrared Nonlinear Optical, Dielectric, and Strong Diamagnetic Characteristics of Semiconducting K3[BiS3] N2 - The ternary sulfido bismuthate K3[BiS3] is synthesized in quantitative yields. The material exhibits nonlinear optical properties with strong second harmonic generation properties at arbitrary wavelengths in the infrared spectral range and a notable laser-induced damage threshold of 5.22 GW cm−2 for pulsed laser radiation at a wavelength of 1040 nm, a pulse duration of 180 fs, and a repetition rate of 12.5 kHz. K3[BiS3] indicates semiconductivity with a direct optical band gap of 2.51 eV. Dielectric and impedance characterizations demonstrate κ values in the range of 6−13 at 1 kHz and a high electrical resistivity. A strong diamagnetic behavior with a susceptibility of −2.73 × 10−4 m3 kg−1 at room temperature is observed. These results suggest it is a promising nonlinear optical candidate for the infrared region. The synergic physical characteristics of K3[BiS3] provide insight into the correlation of optical, electrical, and magnetic properties. KW - Electrical properties KW - Insulators KW - Materials KW - Nonlinear optics KW - Quantum mechanics PY - 2022 DO - https://doi.org/10.1021/acs.jpclett.2c01689 VL - 13 IS - 30 SP - 6987 EP - 6993 PB - ACS Publications AN - OPUS4-55456 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stengel, Dominik A1 - Clobes, M. A1 - Thiele, K. T1 - Investigation on the dynamic behavior of an OHL conductor bundle with light and heavy ice accretion N2 - Under a variety of possible cable vibrations which overhead line conductors can suffer, galloping identifies by large amplitudes at rather low frequencies. Changes of the cross-section as by ice-accretion provide the basis for such vibrations through an aerodynamic instability of drag and lift responses under wind excitation. Two different types of light and heavy ice bodies attached to a quad bundle conductor are analysed in wind tunnel tests. The results of aerodynamic drag and lift coefficients are investigated by means of a finite element model under turbulent wind excitation. It was found that instability can be well simulated for the heavy ice accretion but not for the case of lightly iced conductors. T2 - 8th International Colloquium on Bluff Body Aerodynamics and Applications CY - Boston, MA, USA DA - 07.06.2016 KW - wind turbulence KW - overhead transmission line KW - bundle conductors KW - ice accretion KW - dynamic behaviour PY - 2016 SP - Paper 116, 1 EP - Paper 116, 8 AN - OPUS4-36554 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Deresse, N. E. A1 - Thiele, Marc A1 - Pirskawetz, Stephan A1 - Sarem, M. A1 - Francois, St. A1 - Verstrynge, E. T1 - Evaluation of Concrete Fatigue Damage with Elastic Wave-based Measurement Techniques N2 - The fatigue damage evolution and the fatigue life of quasi-brittle materials such as concrete are not yet completely understood. Accordingly to get better insights, researchers have recently been incorporating advanced measuring techniques in their fatigue experiments. In this research, acoustic emission techniques (AET), active ultrasonic, and deformation measurements are used to track the damage evolution of concrete samples subjected to fatigue loading. The samples are subjected to constant amplitude and stepwise fatigue loading in Brazilian splitting test set-ups. Initially, a good agreement is observed between the deformation and the ultrasonic measurements in capturing the crack propagation during Brazilian splitting tests. The three fatigue damage phases could be identified with all of the three techniques. The Phase II damage rates quantified by deformation measurements and AET in stepwise fatigue tests were used to predict the number of cycles to failure at various stress levels. The predictions were validated using the number of cycles to failure of the constant amplitude fatigue tests. T2 - 36th Conference of the European Working Group on Acoustic Emission CY - Potsdam, Germany DA - 18.09.2024 KW - Concrete KW - Acoustic emission KW - Ultrasonic testing KW - Fatigue PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615677 DO - https://doi.org/10.58286/30228 SN - 1435-4934 VL - 29 IS - 10 SP - 1 EP - 10 PB - NDT.net AN - OPUS4-61567 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Singh, Chandan A1 - Thiele, M. A1 - Dathe, A. A1 - Thamm, S. A1 - Henkel, T. A1 - Sumana, G. A1 - Fritzsche, W. A1 - Czáki, A. T1 - Tri-sodium citrate stabilized gold nanocubes for plasmonic glucose sensing N2 - We report a two-step process for the immobilization of gold nanocubes (Au-NCs) on a glass surface using a combination of extraction and exchange reaction using poly (sodium 4-styrenesulfonate) (PSS) and trisodium citrate (TSC). Cetyltrimethylammonium chloride (CTAC) stabilized gold nanocubes (CTAC/Au-NCs) synthesized by a microfluidic synthesis procedure were successfully deposited on silane-modified glass substrate after extraction of excess CTAC using chloroform followed by exchange of CTAC to TSC on the surface of Au-NCs. Further, TSC/Au-NCs were found to be highly stable and suitable for microfluidic sensing of different glucose concentrations using localized surface plasmon resonance (LSPR) spectroscopy offering an improved sensitivity (126.37 nm/RIU). KW - Gold nanocubes KW - Surfactant KW - Immobilization PY - 2021 DO - https://doi.org/10.1016/j.matlet.2021.130655 SN - 0167-577X SN - 1873-4979 VL - 304 SP - 1 EP - 4 PB - Elsevier CY - New York, NY AN - OPUS4-53216 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Brinkmann, M. A1 - Wiehle, Philipp A1 - Thiele, Marc A1 - Graubner, C.-A. ED - Schermer, D. ED - Brehm, E. T1 - Grundlagen zur Bemessung druckbeanspruchten Lehmmauerwerks N2 - Lehmmauerwerk bietet sich aufgrund seiner zahlreichen ökologischen Vorteile für die Errichtung klimafreundlicher und ressourcenschonender Gebäude an. Um den Anwendungsbereich tragenden Lehmmauerwerks durch eine zeitgemäße Nachweisführung zu erweitern, werden in diesem Beitrag Grundlagen für die Entwicklung eines eurocodekonformen Bemessungskonzepts erarbeitet. Hierzu werden die Ergebnisse umfangreicher experimenteller Untersuchungen an Lehmmauerwerk sowie Lehmsteinen und -mörteln nach Konditionierung bei unterschiedlichen Klimata vorgestellt. Darauf aufbauend erfolgt eine Traglastanalyse druckbeanspruchter Lehmmauerwerkswände mittels numerischer und analytischer Methoden. Die daraus gewonnenen Erkenntnisse werden abschließend in einen an DIN~EN~1996-3/NA angelehnten Bemessungsvorschlag überführt, welcher die materialspezifischen Besonderheiten von Lehmmauerwerk berücksichtigt und eine fundierte Grundlage für eine wirtschaftliche und zuverlässige Nachweisführung darstellt. KW - Druckfestigkeit KW - Lehm KW - Mauerwerk KW - Bemessung KW - Feuchte PY - 2023 SN - 978-3-433-03373-9 DO - https://doi.org/10.1002/9783433611142.ch4 VL - 48 SP - 79 EP - 110 PB - Ernst & Sohn GmbH CY - Berlin ET - 1 AN - OPUS4-57509 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stengel, Dominik A1 - Mehdianpour, Milad A1 - Clobes, M. A1 - Thiele, K. ED - Cunha, A. ED - Caetano, E. ED - Ribeiro, P. ED - Müller, G. T1 - Numerical simulation of an overhead power line section under wind excitation using wind tunnel test results and in-situ measured data N2 - Overhead transmission lines are very sensitive structures in regards to wind action. The cables, spanning over a few hundred meters contribute in particular to the overall action on the suspension towers. These slender structures incorporate both structural nonlinearities from the large deformation of the cables and aerodynamic nonlinearities which need to be accounted for when it is to estimate the system response to strong wind events. In this work, a finite element procedure is presented to model an existing power line section using nonlinear cable elements. The wind force is assumed quasi-steady with force coefficients determined in wind tunnel test on a conductor section. Further, aerodynamic damping is incorporated by considering the relative velocity between cable nodes and oncoming wind flow. The results are compared with on-site measurements of the cable’s support reaction. The results show a significant effect of damping since almost no resonant amplification is visible both in observation and simulation. In addition, wind tunnel tests approved aerodynamic damping to be large for the system of sagging cables, but nonlinear in its nature. It is concluded, that the dynamic response of overhead transmission line cables has to be modeled with care, considering all sources of nonlinearities. That is of particular interest in case of random excitation such as wind because the peak response depends on the probability distribution of the system's response. T2 - EURODYN 2014 - 9th International conference on structural dynamics CY - Porto, Portugal DA - 30.06.2014 KW - Overhead transmission lines KW - Cable dynamics KW - Aerodynamic damping KW - Wind tunnel KW - In-situ measurements PY - 2014 SN - 978-972-752-165-4 SN - 2311-9020 SP - Paper MS07, 1 EP - 6 AN - OPUS4-30993 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stengel, Dominik A1 - Thiele, K. A1 - Clobes, M. A1 - Mehdianpour, Milad T1 - Aerodynamic damping of nonlinear movement of conductor cables in laminar and turbulent wind flow N2 - It is widely accepted that aerodynamic damping is a decisive parameter influencing the dynamic response of overhead transmission line conductors in turbulent wind flow. But anyway, methods of how to account for the effects of aerodynamic damping differ significantly and so might do the results. In this work, the source of aerodynamic damping shall be revised leading to the well-known formulation for a linear pendulum being the result of the relative velocity between the structure and wind flow. Based on wind tunnel tests and validated by simulations, the differences to a pendulum movement of a sagging cable are shown. The reasons for that deviation are the large deflections, resulting in a movement non parallel to the acting wind flow. For some analysis, in particular those in frequency domain, it is practically not possible to incorporate aerodynamic damping implicitly by fluid structure interaction. If the dynamic movement can be linearized at a working point of the mean deflection, a modification to the linear approach is suggested. This approach is validated by simulation with a finite element model of an existing overhead transmission line, calibrated with onsite measurements for wind velocities at lower levels. Further accent is put on the different possibilities to incorporate aerodynamic damping in time step analysis, such as Rayleigh damping or modal damping. The differences between both approaches are emphasized and modal damping is shown to be the most adequate representation of aerodynamic damping. T2 - ICWE14 - 14th International conference on wind engineering CY - Porto Alegre, Brazil DA - 21.06.2015 KW - Aerodynamic damping KW - Conductor cables KW - Overhead transmission lines KW - Wind tunnel experiments KW - Nonlinear finite element simulation PY - 2015 SN - 978-85-66094-07-7 SP - 1 EP - 9 AN - OPUS4-33612 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stengel, Dominik A1 - Thiele, K. A1 - Clobes, M. A1 - Mehdianpour, Milad T1 - Aerodynamic damping of nonlinear movement of conductor cables in wind tunnel tests, numerical simulations and full scale measurements N2 - Aerodynamic damping is a decisive parameter influencing the dynamic response of overhead transmission line conductors. Methods of how to account for the effects of aerodynamic damping differ significantly and so might do the results. In this work, the source of aerodynamic damping being the result of the relative velocity between the structure and wind flow will be revised. Based on wind tunnel tests and validated by simulations, the differences of linear movement compared to a pendulum movement of a sagging cable are shown. The reasons for that Deviation are the large deflections, resulting in a movement non-parallel to the acting wind flow. For analysis in frequency domain, it is not possible to incorporate aerodynamic damping implicitly by fluid structure interaction. If the dynamic movement can be linearized at a working point of the mean deflection, a modification to the linear approach is suggested. This approach is validated by simulation with a finite element model of an existing overhead transmission line, calibrated with full scale measurements. Aerodynamic damping is incorporated in time step analysis by Rayleigh damping and modal damping. The differences between both approaches are emphasized and modal damping is shown to be the most adequate. KW - Aerodynamic damping KW - Overhead transmission lines KW - Conductors KW - Nonlinearities PY - 2017 DO - https://doi.org/10.1016/j.jweia.2017.07.002 SN - 0167-6105 SN - 1872-8197 VL - 169 SP - 47 EP - 53 PB - Elsevier AN - OPUS4-41028 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Liehr, Sascha A1 - Lenke, Philipp A1 - Krebber, Katerina A1 - Seeger, M. A1 - Thiele, E. A1 - Metschies, H. A1 - Gebreselassie, B. A1 - Münich, J.C. A1 - Stempniewski, L. ED - Francis Berghmans, ED - Mignani, Anna Grazia ED - Cutolo, Antonello ED - Patrick P. Meyrueis, ED - Thomas P. Pearsall, T1 - Distributed strain measurement with polymer optical fibers integrated into multifunctional geotextiles N2 - Fiber optic sensors based on polymer optical fibers (POF) have the advantage of being very elastic and robust at the same time. Unlike silica fibers, standard PMMA POF fibers can be strained to more than 40% while fully maintaining their light guiding properties. We investigated POF as a distributed strain sensor by analysing the backscatter increase at the strained section using the optical time domain reflectometry (OTDR) technique. This sensing ability together with its high robustness and break-down strain makes POF well-suited for integration into technical textiles for structural health monitoring purposes. Within the European research project POLYTECT (Polyfunctional textiles against natural hazards) technical textiles with integrated POF sensors, among others sensors are being developed for online structural health monitoring of geotechnical structures. Mechanical deformation in slopes, dams, dikes, embankments and retrofitted masonry structures is to be detected before critical damage occurs. In this paper we present the POF strain sensor properties, reactions to disturbing influences as temperature and bends as well as the results of the different model tests we conducted within POLYTECT. We further show the potential of perfluorinated graded-index POF for distributed strain sensing with increased spatial resolution and measurement lengths. T2 - Optical Sensors 2008 CY - Strasbourg, France DA - 2008-04-07 KW - Fiber optic sensors KW - OTDR KW - Polymer optical fibers (POF) KW - POF sensors KW - Distributed sensor KW - Strain sensor KW - Geotextiles KW - Structural health monitoring PY - 2008 SN - 978-0-8194-7201-4 DO - https://doi.org/10.1117/12.780508 SN - 0277-786X N1 - Serientitel: Proceedings of SPIE – Series title: Proceedings of SPIE VL - 7003 IS - 7003 SP - 700302-1 - 700302-15 PB - SPIE CY - Bellingham AN - OPUS4-17951 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -