@phdthesis{Riesel,
  author    = {Riesel, Tobias},
  title     = {Analyse des Querkrafttragverhaltens bewehrter Bauteile aus Porenbeton mit den Methoden der mathematischen Optimierung},
  publisher = {Bauhaus-Universit{\"a}t Weimar Universit{\"a}tsverlag},
  address   = {Weimar},
  doi       = {10.25643/bauhaus-universitaet.1835},
  url       = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20130128-18351},
  school      = {Bauhaus-Universit{\"a}t Weimar},
  pages     = {178},
  abstract  = {Im Rahmen der Arbeit wird das Querkrafttragverhalten bewehrter Bauteile aus Porenbeton untersucht. Die vorherrschende Beschreibung des inneren Kr{\"a}ftezustandes basiert auf der Modellvorstellung eines Fachwerks oder Sprengwerks mit Stahlzugstreben und Betondruckstreben. Ziel ist die Entwicklung eines alternativen Verfahrens zur Ermittlung des inneren Kr{\"a}ftezustandes. Ausgehend vom Prinzip des Minimums des elastischen Gesamtpotentials wird eine Extremalaufgabe f{\"u}r das mechanische Problem formuliert. Die numerische Umsetzung basiert auf der {\"U}berf{\"u}hrung der Extremalaufgabe in eine nichtlineare Optimierungsaufgabe. Diese l{\"a}sst sich mit Standardsoftware l{\"o}sen. Der Vorteil dieser Vorgehensweise besteht darin, dass das grundlegende Verfahren unabh{\"a}ngig vom verwendeten Materialmodell ist. Nichtlineare Spannungs-Dehnungs-Beziehungen oder die Ber{\"u}cksichtigung der Rissbildung erfordern keine Anpassung des Berechnungsalgorithmus. Bewehrte Porenbetonbauteile besitzen im Hinblick auf das Trag- und Verformungsverhalten einige Besonderheiten. Berechnungsans{\"a}tze f{\"u}r Stahlbetonelemente lassen sich nicht ohne entsprechende Modifikationen {\"u}bertragen lassen. Die Bewehrung wird aus glatten St{\"a}ben hergestellt, so dass nach der Herstellung nur ein Haftverbund wirksam ist. Dieser kann {\"u}ber die Lebensdauer teilweise oder vollst{\"a}ndig versagen. Die Kraft{\"u}bertragung zwischen den Verbundelementen muss durch entsprechende Kopplungselemente (z.B. Querst{\"a}be, B{\"u}gel, Endwinkel) sichergestellt werden. Der Bewehrungskorb ist im Porenbeton gebettet. Aufgrund der relativ niedrigen Festigkeit bzw. Steifigkeit des Porenbetons und des teilweise unwirksamen Verbundes treten Relativverschiebungen zwischen beiden Verbundmaterialien auf. Hier sind die Ursachen daf{\"u}r zu finden, dass die Beanspruchung der Querkraftbewehrung viel geringer ist als bei vergleichbaren Stahlbetonbalken. Der Querkraftbewehrungsgrad erlaubt keine R{\"u}ckschl{\"u}sse auf den Querkraftwiderstand. Das zentrale Anliegen der Arbeit ist die Implementierung nichtlinearer Materialans{\"a}tze, der Rissbildung des Porenbetons sowie der porenbetonspezifischen Besonderheiten verschieblicher Verbund, diskrete Verankerung der Bewehrung und Relativverschiebungen zwischen Porenbeton und Bewehrung) in das Berechnungsmodell. Die Leistungsf{\"a}higkeit des entwickelten Berechnungsmodells wird anhand von Beispielen demonstriert. Die Kr{\"a}fte in der Bewehrung sowie das Tragwerksverhalten werden realit{\"a}tsnah bestimmt.},
  subject      = {Querkraft},
  language  = {de}
}
@inproceedings{BrossmannMueller,
  author    = {Broßmann, Marko and M{\"u}ller, Karl-Heinz},
  title     = {STOCHASTISCHE ANALYSE VON STAHLBETONBALKEN IM GRENZZUSTAND DER ADAPTION UNTER BER{\"u}CKSICHTIGUNG DER STEIFIGKEITSDEGRADATION},
  editor    = {G{\"u}rlebeck, Klaus and K{\"o}nke, Carsten},
  organization    = {Bauhaus-Universit{\"a}t Weimar},
  doi       = {10.25643/bauhaus-universitaet.2934},
  url       = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170327-29341},
  pages     = {20},
  abstract  = {Am Beispiel eines 3-feldrigen Durchlauftr{\"a}gers wird die Versagenswahrscheinlichkeit von wechselnd belasteten Stahlbetonbalken bez{\"u}glich des Grenzzustandes der Adaption (Einspielen, shakedown) untersucht. Die Adaptionsanalyse erfolgt unter Ber{\"u}cksichtigung der beanspruchungschabh{\"a}ngigen Degradation der Biegesteifigkeit infolge Rissbildung. Die damit verbundene mechanische Problemstellung kann auf die Adaptionsanalyse linear elastisch - ideal plastischer Balkentragwerke mit unbekannter aber begrenzter Biegesteifigkeit zur{\"u}ckgef{\"u}hrt werden. Die Versagenswahrscheinlichkeit wird unter Ber{\"u}cksichtigung stochastischer Tragwerks- und Belastungsgr{\"o}ßen berechnet. Tragwerkseigenschaften und st{\"a}ndige Lasten gelten als zeitunabh{\"a}ngige Zufallsgr{\"o}ßen. Zeitlich ver{\"a}nderliche Lasten werden als nutzungsdauerbezogene Extremwerte POISSONscher Rechteck-Pulsprozesse unter Ber{\"u}cksichtigung zeitlicher {\"U}berlagerungseffekte modelliert, so dass die Versagenswahrscheinlichkeit ebenfalls eine nutzungsdauerbezogene Gr{\"o}ße ist. Die mechanischen Problemstellungen werden numerisch mit der mathematischen Optimierung gel{\"o}st. Die Versagenswahrscheinlichkeit wird auf statistischem Weg mit der Monte-Carlo-Methode gesch{\"a}tzt.},
  subject      = {Architektur <Informatik>},
  language  = {de}
}
@phdthesis{Golbs2009,
  author    = {Golbs, Christian},
  title     = {Probabilistische seismische Gef{\"a}hrdungsanalysen auf der Grundlage von Epizentrendichten und ihre ingenieurpraktischen Anwendungsgebiete},
  doi       = {10.25643/bauhaus-universitaet.1412},
  url       = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20100112-14982},
  school      = {Bauhaus-Universit{\"a}t Weimar},
  year      = {2009},
  abstract  = {Ziel der Arbeit ist es, eine neue Methode der seismischen Gef{\"a}hrdungsabsch{\"a}tzung vorzustellen. Es wird die Absch{\"a}tzung der seismischen Gef{\"a}hrdung ohne die h{\"a}ufig angewandten Einteilungen in seismische Quellzonen beschrieben. Die vorgestellte Methode basiert auf Nachbarschaftsanalysen von Epizentren. Diese Nachbarschaftsanalysen erm{\"o}glichen ein selbst generierendes seismisches Quellenmodell. Entwicklung, Parameterstudien und Anwendung der Methode werden gezeigt.},
  subject      = {Gef{\"a}hrdung},
  language  = {de}
}
@phdthesis{Chawdhury,
  author    = {Chawdhury, Samir},
  title     = {Partitioned Algorithms using Vortex Particle Methods for Fluid-Structure Interaction of Thin-walled Flexible Structures},
  publisher = {arts + science weimar GmbH},
  address   = {Weimar},
  isbn      = {978-3-95773-297-2},
  doi       = {10.25643/bauhaus-universitaet.6404},
  url       = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20230703-64042},
  school      = {Bauhaus-Universit{\"a}t Weimar},
  pages     = {256},
  abstract  = {Structures under wind action can exhibit various aeroelastic interaction phenomena, which can lead to destructive and catastrophic events. Such unstable interaction can be beneficially used for small-scale aeroelastic energy harvesting. Proper understanding and prediction of fluid-structure interactions (FSI) phenomena are therefore crucial in many engineering fields. This research intends to develop coupled FSI models to extend the applicability of Vortex Particle Methods (VPM) for numerically analysing the complex FSI of thin-walled flexible structures under steady and fluctuating incoming flows. In this context, the flow around deforming thin bodies is analysed using the two-dimensional and pseudo-three-dimensional implementations of VPM. The structural behaviour is modelled and analysed using the Finite Element Method. The partitioned coupling approach is considered because of the flexibility of using different mathematical procedures for solving fluid and solid mechanics. The developed coupled models are validated with several benchmark FSI problems in the literature. Finally, the models are applied to several fundamental and application field of FSI problems of different thin-walled flexible structures irrespective of their size.},
  subject      = {Windenergie},
  language  = {en}
}
@article{AnicPenavaSarhosisetal.,
  author    = {Anic, Filip and Penava, Davorin and Sarhosis, Vasilis and Abrahamczyk, Lars},
  title     = {Development and Calibration of a 3D Micromodel for Evaluation of Masonry Infilled RC Frame Structural Vulnerability to Earthquakes},
  series = {Geosciences},
  volume    = {2021},
  journal   = {Geosciences},
  number    = {Voume 11, issue 11, article 468},
  publisher = {MDPI},
  address   = {Basel},
  doi       = {10.3390/geosciences11110468},
  url       = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20211202-45370},
  pages     = {23},
  abstract  = {Within the scope of literature, the influence of openings within the infill walls that are bounded by a reinforced concrete frame and excited by seismic drift forces in both in- and out-of-plane direction is still uncharted. Therefore, a 3D micromodel was developed and calibrated thereafter, to gain more insight in the topic. The micromodels were calibrated against their equivalent physical test specimens of in-plane, out-of-plane drift driven tests on frames with and without infill walls and openings, as well as out-of-plane bend test of masonry walls. Micromodels were rectified based on their behavior and damage states. As a result of the calibration process, it was found that micromodels were sensitive and insensitive to various parameters, regarding the model's behavior and computational stability. It was found that, even within the same material model, some parameters had more effects when attributed to concrete rather than on masonry. Generally, the in-plane behavior of infilled frames was found to be largely governed by the interface material model. The out-of-plane masonry wall simulations were governed by the tensile strength of both the interface and masonry material model. Yet, the out-of-plane drift driven test was governed by the concrete material properties.},
  subject      = {Verwundbarkeit},
  language  = {en}
}
@article{StaubachMachacekSkowroneketal.2020,
  author    = {Staubach, Patrick and Machacek, Jan and Skowronek, Josefine and Wichtmann, Torsten},
  title     = {Vibratory pile driving in water-saturated sand: Back-analysis of model tests using a hydro-mechanically coupled CEL method},
  series = {Soils and Foundations},
  volume    = {2021},
  journal   = {Soils and Foundations},
  number    = {Volume 61, Issue 1},
  publisher = {Elsevier, Science Direct},
  address   = {Amsterdam},
  doi       = {10.1016/j.sandf.2020.11.005},
  url       = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20210203-43571},
  pages     = {144 -- 159},
  year      = {2020},
  abstract  = {The development of a hydro-mechanically coupled Coupled-Eulerian-Lagrangian (CEL) method and its application to the back-analysisof vibratory pile driving model tests in water-saturated sand is presented. The predicted pile penetration using this approachis in good agreement with the results of the model tests as well as with fully Lagrangian simulations. In terms of pore water pressure, however, the results of the CEL simulation show a slightly worse accordance with the model tests compared to the Lagrangian simulation. Some shortcomings of the hydro-mechanically coupled CEL method in case of frictional contact problems and pore fluids with high bulk modulus are discussed. Lastly, the CEL method is applied to the simulation of vibratory driving of open-profile piles under partially drained conditions to study installation-induced changes in the soil state. It is concluded that the proposed method is capable of realistically reproducing the most important mechanisms in the soil during the driving process despite its addressed shortcomings.},
  subject      = {Plastische Deformation},
  language  = {en}
}
@inproceedings{VilceanuAbrahamczykMorgenthal,
  author    = {V{\^i}lceanu, Victor and Abrahamczyk, Lars and Morgenthal, Guido},
  title     = {Nonlinear Analysis of Structures: Wind Induced Vibrations},
  doi       = {10.25643/bauhaus-universitaet.4033},
  url       = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20191122-40337},
  pages     = {183},
  abstract  = {The proceedings at hand are the result of the International Master Course Module: "Nonlinear Analysis of Structures: Wind Induced Vibrations" held at the Faculty of Civil Engineering at Bauhaus-University Weimar, Germany in the summer semester 2019 (April - August). This material summarizes the results of the project work done throughout the semester, provides an overview of the topic, as well as impressions from the accompanying programme. Wind Engineering is a particular field of Civil Engineering that evaluates the resistance of structures caused by wind loads. Bridges, high-rise buildings, chimneys and telecommunication towers might be susceptible to wind vibrations due to their increased flexibility, therefore a special design is carried for this aspect. Advancement in technology and scientific studies permit us doing research at small scale for more accurate analyses. Therefore scaled models of real structures are built and tested for various construction scenarios. These models are placed in wind tunnels where experiments are conducted to determine parameters such as: critical wind speeds for bridge decks, static wind coefficients and forces for buildings or bridges. The objective of the course was to offer insight to the students into the assessment of long-span cable-supported bridges and high-rise buildings under wind excitation. The participating students worked in interdisciplinary teams to increase their knowledge in the understanding and influences on the behaviour of wind-sensitive structures.},
  subject      = {Ingenieurbau},
  language  = {en}
}
@inproceedings{AbrahamczykSchwarz,
  author    = {Abrahamczyk, Lars and Schwarz, Jochen},
  title     = {Forecast Engineering: From Past Design to Future Decision 2017},
  doi       = {10.25643/bauhaus-universitaet.4034},
  url       = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20191122-40344},
  pages     = {221},
  abstract  = {The design of engineering structures takes place today and in the past on the basis of static calculations. The consideration of uncertainties in the model quality becomes more and more important with the development of new construction methods and design requirements. In addition to the traditional forced-based approaches, experiences and observations about the deformation behavior of components and the overall structure under different exposure conditions allow the introduction of novel detection and evaluation criteria. The proceedings at hand are the result from the Bauhaus Summer School Course: Forecast Engineering held at the Bauhaus-Universit{\"a}t Weimar, 2017. It summarizes the results of the conducted project work, provides the abstracts of the contributions by the participants, as well as impressions from the accompanying programme and organized cultural activities. The special character of this course is in the combination of basic disciplines of structural engineering with applied research projects in the areas of steel and reinforced concrete structures, earthquake and wind engineering as well as informatics and linking them to mathematical methods and modern tools of visualization. Its innovative character results from the ambitious engineering tasks and advanced modeling demands.},
  subject      = {Proceedings},
  language  = {en}
}
@inproceedings{AbrahamczykSchwarz,
  author    = {Abrahamczyk, Lars and Schwarz, Jochen},
  title     = {Forecast Engineering: From Past Design to Future Decision 2018},
  doi       = {10.25643/bauhaus-universitaet.4036},
  url       = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20191126-40364},
  pages     = {112},
  abstract  = {Institute of Structural Engineering, Institute of Structural Mechanics, as well as Institute for Computing, Mathematics and Physics in Civil Engineering at the faculty of civil engineering at the Bauhaus-Universit{\"a}t Weimar presented special topics of structural engineering to highlight the broad spectrum of civil engineering in the field of modeling and simulation. The summer course sought to impart knowledge and to combine research with a practical context, through a challenging and demanding series of lectures, seminars and project work. Participating students were enabled to deal with advanced methods and its practical application. The extraordinary format of the interdisciplinary summer school offers the opportunity to study advanced developments of numerical methods and sophisticated modelling techniques in different disciplines of civil engineering for foreign and domestic students, which go far beyond traditional graduate courses. The proceedings at hand are the result from the Bauhaus Summer School course: Forecast Engineering held at the Bauhaus-Universit{\"a}t Weimar, 2018. It summarizes the results of the conducted project work, provides the abstracts/papers of the contributions by the participants, as well as impressions from the accompanying programme and organized cultural activities.},
  subject      = {Proceedings},
  language  = {en}
}
@misc{Bendalla,
  type      = {Master Thesis},
  author    = {Bendalla, Abdulmagid Sedig Khalafallah},
  title     = {Nonlinear Numerical Modelling of Cable Elements in Bridges for Dynamic Analysis},
  doi       = {10.25643/bauhaus-universitaet.3994},
  url       = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20191007-39940},
  school      = {Bauhaus-Universit{\"a}t Weimar},
  pages     = {107},
  abstract  = {Identifying cable force with vibration-based methods has become widely used in engineering practice due to simplicity of application. The string taut theory provides a simple definition of the relationship between natural frequencies and the tension force of a cable. However, this theory assumes a perfectly flexible non-sagging cable pinned at its ends. These assumptions do not reflect all cases, especially when the cable is short, under low tension forces or the supports are partially flexible. Extradosed bridges, which are distinguished from cable-stayed bridges by their low pylon height, have shorter cables. Therefore the application of the conventional string taut theory to identify cable forces on extradosed bridge cables might be inadequate to identify cable forces. In this work, numerical modelling of an extradosed bridge cable saddled on a circular deviator at pylon is conducted. The model is validated with the catenary analytical solution and its static and dynamic behaviours are studied. The effect of a saddle support is found to positively affect the cable stiffness by geometric means; longer saddle radius increases the cable stiffness by suppressing the deformations near the saddle. Further, accounting the effects of bending stiffness in the numerical model by using beam elements show considerable deviation from models with truss elements (i.e. zero bending stiffness). This deviation is manifested when comparing the static and dynamic properties. This motivates a more thorough study of bending stiffness effects on short cables. Bending stiffness effects are studied using two rods connected with several springs along their length. Under bending moments, the springs resist the rods' relative axial displacement by the springs' transverse component. This concept is used to identify bending stiffness values by utilizing the parallel axis theorem to quantify ratios of the second moment of area. These ratios are calculated based on the setup of the springs (e.g. number of springs per unit length, transverse stiffness, etc...). The numerical model based on this concept agrees well with the theoretical values computed using upper and lower bounds of the parallel axis theorem. The proposed concept of quantifying ratios of the second moment of area using springs as connection between cable rods is applied on an actual extradosed bridge geometry. The model is examined by comparison to the previously validated global numerical model. The two models showed good correlation under various changing parameters. This allowed further study of the effects of stick/slip behaviour between cable rods on an actual bridge geometry.},
  subject      = {Kabel},
  language  = {en}
}