@article{NagelSimonKuemmeletal., author = {Nagel, Falk and Simon, Flaviu and K{\"u}mmel, Benjamin and Bergmann, Jean Pierre and Hildebrand, J{\"o}rg}, title = {Optimization Strategies for Laser Welding High Alloy Steel Sheets}, series = {Physics Procedia}, journal = {Physics Procedia}, doi = {10.1016/j.phpro.2014.08.040}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170425-31554}, pages = {1242 -- 1251}, abstract = {A known phenomenon during laser welding of thin sheets is the deformation caused by thermally induced stresses. This deformation can result in a change of the gap width between the welded parts, which leads to an unstable welding process. Inducing displacements by using a second heat source will compensate for the change in gap width, hence optimizing the welding process. The base material is 1 mm thick austenitic stainless steel 1.4301, which is welded by a CO2 laser. The second heat source is a diode laser. The gap between the welded parts was set between 0.05 mm and 0.1 mm. The influence of the second heat source on the welding process and the welding result is described. The usage of a second heat source allows a higher gap width to be set prior to the welding process. The results of the numerical simulation were found to be corresponding to those of the experiments.}, subject = {Edelstahl}, language = {en} } @article{MeyerKohlstockHauptHeldtetal., author = {Meyer-Kohlstock, Daniel and Haupt, Thomas and Heldt, Erik and Heldt, Nils and Kraft, Eckhard}, title = {Biochar as Additive in Biogas-Production from Bio-Waste}, series = {ENERGIES}, journal = {ENERGIES}, doi = {10.3390/en9040247}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170406-31119}, abstract = {Previous publications about biochar in anaerobic digestion show encouraging results with regard to increased biogas yields. This work investigates such effects in a solid-state fermentation of bio-waste. Unlike in previous trials, the influence of biochar is tested with a setup that simulates an industrial-scale biogas plant. Both the biogas and the methane yield increased around 5\% with a biochar addition of 5\%-based on organic dry matter biochar to bio-waste. An addition of 10\% increased the yield by around 3\%. While scaling effects prohibit a simple transfer of the results to industrial-scale plants, and although the certainty of the results is reduced by the heterogeneity of the bio-waste, further research in this direction seems promising.}, subject = {Festphasen-Fermentation}, language = {en} } @article{MeelSatirasetthaveeKanitpongetal., author = {Meel, Inder P. and Satirasetthavee, Dussadee and Kanitpong, Kunnawee and Taneerananon, Pichai}, title = {Using Czech TCT to Assess Safety Impact of Deceleration Lane at Thai U-turns}, series = {ENGINEERING JOURNAL-THAILAND}, journal = {ENGINEERING JOURNAL-THAILAND}, doi = {10.4186/ej.2016.20.1.121}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170406-31097}, pages = {121 -- 135}, abstract = {Purpose of this study is to evaluate safety impact of the deceleration lane at the Upstream Zone of at-grade U-turns on 4-lane divided Thai highways. A substantial speed reduction is required by vehicles for diverging and making U-turn, and the deceleration lanes are provided for this purpose. These lanes are also providing a storage space for the U-turning vehicles to avoid unnecessary blockage of through lanes and reduce the potential of rear-end collisions. The safety at the U-turn is greatly influenced by the proper or improper use of the deceleration lanes. Subject to their length, full or partial speed adjustment can occur within the deceleration lane also the road users' behavior is influenced. To assess the safety impact, the four groups of U-turns with the varying length of deceleration lanes were identified. Owing to limitation of availability and reliability of road crash data in Thailand, widely accepted Traffic Conflict Technique (TCT) was used as an alternative and proactive methodology. The U-turns' geometric data, traffic conflicts and volume data were recorded in the field at 8 locations, 8 hours per location. Severity Conflict Rate (SCR) was assessed by applying a weighing factor (based on the severity grades according to the Czech TCT) to the observed conflicts related to the conflicting traffic volumes. A comparative higher value of SCR represents a lower level of safety. According to the results, increase in the functional length of the deceleration lane yields a lower value of SCR and a higher level of the road safety.}, subject = {Verkehrssicherheit}, language = {en} } @article{MorgenthalYamasaki, author = {Morgenthal, Guido and Yamasaki, Y.}, title = {Aerodynamic Behaviour of Very Long Cable-Stayed Bridges during Construction}, series = {Procedia Engineering}, journal = {Procedia Engineering}, doi = {10.1016/j.proeng.2011.07.184}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170425-31525}, pages = {1463 -- 1471}, abstract = {Stonecutters and Sutong Bridge have pushed the world record for main span length of cable-stayed bridges to over 1000m. The design of these bridges, both located in typhoon prone regions, is strongly influenced by wind effects during their erection. Rigorous wind tunnel test programmes have been devised and executed to determine the aerodynamic behaviour of the structures in the most critical erection conditions. Testing was augmented by analytical and numerical analyses to verify the safety of the structures throughout construction and to ensure that no serviceability problems would affect the erection process. This paper outlines the wind properties assumed for the bridge sites, the experimental test programme with some of its results, the dynamic properties of the bridges during free cantilevering erection and the assessment of their aerodynamic performance. Along the way, it discusses the similarities and some revealing differences between the two bridges in terms of their dynamic response to wind action.}, subject = {Kabelbr{\"u}cke}, language = {en} } @article{ChubukovKapitanovMoninaetal., author = {Chubukov, A. and Kapitanov, Valeriy and Monina, Olga and Silyanov, Valentin and Brannolte, Ulrich}, title = {Calculation of Traffic Capacity of Signaled Intersections}, series = {Transportation Research Procedia 20}, journal = {Transportation Research Procedia 20}, doi = {10.1016/j.trpro.2017.01.032}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170401-30964}, pages = {125 -- 131}, abstract = {In order to calculate traffic capacity of signaled intersections, it was suggested to apply an approach based on the concept of congestions. The paper states examples of traffic capacity calculation.}, subject = {Verkehr}, language = {en} } @article{MeelBrannolteSatirasetthaveeetal., author = {Meel, Inder P. and Brannolte, Ulrich and Satirasetthavee, Dussadee and Kanitpong, Kunnawee}, title = {Safety impact of application of auxiliary lanes at downstream locations of Thai U-turns}, series = {IATSS Research}, journal = {IATSS Research}, doi = {10.1016/j.iatssr.2016.06.002}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170401-31016}, abstract = {To assess the safety impact of auxiliary lanes at downstream locations of U-turns, the Traffic Conflict Technique was used. On the basis of the installed components at those locations, four types of U-turns were identified: those without any auxiliary lane, those with an acceleration lane, those with outer widening, and those with both an acceleration lane and outer widening. The available crash data is unreliable, therefore to assess the level of road safety, Conflict Indexes were formulated to put more emphasis on severe crashes than on slight ones by using two types of weighting coefficients. The first coefficient was based on the subjective assessment of the seriousness of the conflict situation and the second was based on the relative speed and angle between conflicting streams. A comparatively higher Conflict Index value represents a lower level of road safety. According to the results, a lower level of road safety occurs if two components apply or if a location is without any auxiliary lane. The highest level of road safety occurs if the layout includes only a single component, either an acceleration lane or outer widening.}, subject = {Verkehrssicherheit}, language = {en} } @article{WangArash, author = {Wang, Quan and Arash, Behrouz}, title = {Announcement of a virtual special issue on computational carbon nanoscience}, series = {Carbon}, journal = {Carbon}, doi = {10.1016/j.carbon.2015.05.082}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170428-31695}, pages = {370 -- 372}, abstract = {The Carbon journal is pleased to introduce a themed collection of recent articles in the area of computational carbon nanoscience. This virtual special issue was assembled from previously published Carbon articles by Guest Editors Quan Wang and Behrouz Arash, and can be accessed as a set in the special issue section of the journal website homepage: www.journals.elsevier.com/carbon. The article below by our guest editors serves as an introduction to this virtual special issue, and also a commentary on the growing role of computation as a tool to understand the synthesis and properties of carbon nanoforms and their behavior in composite materials.}, subject = {Kohlenstoff}, language = {en} } @article{BremerWollweberWeigandetal., author = {Bremer, K. and Wollweber, M. and Weigand, F. and Rahlves, M. and Kuhne, Michael and Helbig, R. and Roth, B.}, title = {Fibre Optic Sensors for the Structural Health Monitoring of Building Structures}, series = {Procedia Technology 26}, journal = {Procedia Technology 26}, doi = {10.1016/j.protcy.2016.08.065}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170331-30912}, pages = {524 -- 529}, abstract = {In this work different fibre optic sensors for the structural health monitoring of civil engineering structures are reported. A fibre optic crack sensor and two different fibre optic moisture sensors have been designed to detect the moisture ingress in concrete based building structures. Moreover, the degeneration of the mechanical properties of optical glass fibre sensors and hence their long-term stability and reliability due to the mechanical and chemical impact of the concrete environment is discussed as well as the advantage of applying a fibre optic sensor system for the structural health monitoring of sewerage tunnels is demonstrated.}, subject = {Structural Health Monitoring}, language = {en} } @article{MasoodKharalNasir, author = {Masood, R. and Kharal, M. K. N. and Nasir, A.R.}, title = {Is BIM Adoption Advantageous for Construction Industry of Pakistan?}, series = {Procedia Engineering}, journal = {Procedia Engineering}, doi = {10.1016/j.proeng.2014.07.021}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170425-31509}, pages = {229 -- 238}, abstract = {Lack of Information technology applications on construction projects lead to complex flow of data during project life cycle. Building Information Modeling (BIM) has gained attention in the Architectural, Engineering and Construction (AEC) industry, envisage the use of virtual n-dimensional (n-D) models to identify potential conflicts in design, construction or operational of any facility. A questionnaire has been designed to investigate perceptions regarding BIM advantages. Around 102 valid responses received from diversified stakeholders. Results showed very low BIM adoption with low level of 'Buzz'. BIM is a faster and more effective method for designing and construction management, it improves quality of the design and construction and reduces rework during construction; which came out as the top thee advantages according to the perception of AEC professionals of Pakistan.BIM has least impact on reduction of cost, time and human resources. This research is a bench mark study to understand adoption and advantageous of BIM in Pakistan Construction Industry.}, subject = {Building Information Modeling}, language = {en} } @article{MeunierWaltherWorsleyetal., author = {Meunier, David and Walther, Christoph and Worsley, Tom and Dahl, Alexander and Le Ma{\^i}tre, H{\´e}l{\`e}ne}, title = {Evolutions of the Reference Values Used in Transport CBA National Guidelines of 3 Countries and What they Reveal}, series = {Transportation Research Procedia 13}, journal = {Transportation Research Procedia 13}, doi = {10.1016/j.trpro.2016.05.011}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170406-31106}, pages = {100 -- 113}, abstract = {The paper presents, analyses and compares the evolution of reference values used in national guidelines issued for cost-benefit analysis of transport infrastructure projects, over the last fifty years, in France, UK and Germany.}, subject = {Verkehrsinfrastruktur}, language = {en} } @phdthesis{Froebel, author = {Fr{\"o}bel, Toni}, title = {Data coupled civil engineering applications: Modeling and quality assessment methods}, publisher = {Verlag der Bauhaus-Universit{\"a}t Weimar 2013}, address = {Weimar}, isbn = {978-3-86068-486-3}, doi = {10.25643/bauhaus-universitaet.1836}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20130128-18366}, school = {Bauhaus-Universit{\"a}t Weimar}, pages = {153}, abstract = {The planning process in civil engineering is highly complex and not manageable in its entirety. The state of the art decomposes complex tasks into smaller, manageable sub-tasks. Due to the close interrelatedness of the sub-tasks, it is essential to couple them. However, from a software engineering point of view, this is quite challenging to do because of the numerous incompatible software applications on the market. This study is concerned with two main objectives: The first is the generic formulation of coupling strategies in order to support engineers in the implementation and selection of adequate coupling strategies. This has been achieved by the use of a coupling pattern language combined with a four-layered, metamodel architecture, whose applicability has been performed on a real coupling scenario. The second one is the quality assessment of coupled software. This has been developed based on the evaluated schema mapping. This approach has been described using mathematical expressions derived from the set theory and graph theory by taking the various mapping patterns into account. Moreover, the coupling quality has been evaluated within the formalization process by considering the uncertainties that arise during mapping and has resulted in global quality values, which can be used by the user to assess the exchange. Finally, the applicability of the proposed approach has been shown using an engineering case study.}, subject = {Data exchange, Schema mapping, Quality assessment, Uncertainty, Coupling, BIM, Design patterns, Metamodel architecture}, language = {en} } @phdthesis{SalehiSadaghiani, author = {Salehi Sadaghiani, Mohamad Reza}, title = {Suffusion Phenomenon in Widely Graded Soils - Influence of Homogeneity}, publisher = {Blueprint}, address = {Weimar}, doi = {10.25643/bauhaus-universitaet.2681}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20161020-26819}, school = {Bauhaus-Universit{\"a}t Weimar}, pages = {160}, abstract = {Problemstellung und Zielsetzung der Arbeit D{\"a}mme und Deiche f{\"u}r z.B. Fluß-, Kanal- oder Speicherbauten sind Erdbauwerke mit großer Kubatur, die meistens großen Platzbedarf und enormen Materialverbrauch erfordern. Aus der Vielfalt von Materialien die uns zur Herstellung der D{\"a}mme zur Verf{\"u}gung stehen, muss immer die wirtschaftlichste L{\"o}sung gefunden werden. Aus diesem Grund werden im Dammbau, die im Umfeld nat{\"u}rlich anstehenden B{\"o}den verwendet. Meist handelt es sich um weitgestufte B{\"o}den, so dass bei der Herstellung der Erdbauwerke eine potenzielle Gefahr der Entmischung besteht. Bei einer hydraulischen Beanspruchung solcher B{\"o}den k{\"o}nnen verschiedene Prozesse der inneren Erosion auftreten, deren Ph{\"a}nomene in Filtration, Suffosion, Kolmation und r{\"u}ckschreitende Erosion unterschieden werden. In der Geotechnik beschreibt man den Transport von Feinteilen aus einem Erdstoff mit dem Begriff "Suffosion". Kommt es zum Materialtransport innerhalb des Bodens, verursacht dies eine Erh{\"o}hung der Wasserdurchl{\"a}ssigkeit und des Porenanteils. Gleichzeitig nehmen die Raumdichte des Bodengef{\"u}ges und die Tragf{\"a}higkeit des Bodens ab. Suffosion ist geometrisch m{\"o}glich, wenn die Porenengstellen der groben, skelettbildenden Fraktionen gr{\"o}ßer als die Korngr{\"o}ßen der mobilen feinen Fraktionen des Bodens sind. Sobald ein kritischer hydraulischer Gradient erreicht wird, werden die mobilen feinen Partikel transportiert. Wegen des starken Einfl usses der Struktur spielt die Homogenit{\"a}t des Korngef{\"u}ges bei allen Prozessen der inneren Erosion eine große Rolle. Die Effekte der Suffosion k{\"o}nnen bei verschiedenen Erdbauwerken unterschiedliche Wirkung haben und zur Beeintr{\"a}chtigung der Funktion oder zu Sch{\"a}den f{\"u}hren. Zu den Aufgaben der Ingenieure z{\"a}hlt die Absch{\"a}tzung, inwiefern die hydrodynamischen Einwirkungen einen standsicherheitrelevanten Einfl uss haben. Die Rolle der Partikelzusammensetzung zur Initialisierung und Fortsetzung des Materialtransportes (Suffosion) wurde noch nicht vollst{\"a}ndig untersucht. Alle g{\"a}ngigen Kriterien gehen von einer Homogenit{\"a}t des Gef{\"u}ges aus. Daher ist das Hauptziel dieser Arbeit, ein analytisches Suffosionskriterium unter Ber{\"u}cksichtigung der Homogenit{\"a}t abzuleiten. Das Kriterium soll in der Lage sein, die mobilen, lokal beweglichen, sowie die suffosiven, global beweglichen Fraktionen eines weitgestuften Bodens einzusch{\"a}tzen. Stand der Wissenschaft Geometrische Suffosionskriterien basieren auf Untersuchungen, die zur Dimensionierung von Erdstofffi ltern im Dammbau entwickelt wurden. Als Eingangsparameter werden die Korngr{\"o}ßenverteilungen der B{\"o}den herangezogen. Fundamentale geometrische Suffosionskriterien wurden u. a. von Ziems (1969), Burenkova (1993), Kenney \& Lau (1986), Wan und Fell (2008) und Witt (2013) entwickelt. Mit den verf{\"u}gbaren Kriterien zur Beurteilung der inneren Suffosionsbest{\"a}ndigkeit kann die Wahrscheinlichkeit eines Materialtransportes nicht quantitativ beurteilt werden. Die zahlreichen Kriterien basieren im Wesentlichen auf empirischen Ans{\"a}tzen und sind nur f{\"u}r spezifische Bodenarten und Randbedingungen anwendbar. Die Anwendungsgrenzen der Suffosionskriterien werden hinsichtlich der Bodenart und des Ungleichf{\"o}rmigkeitsgrades meist {\"u}berschritten. Dar{\"u}ber hinaus ist das Ph{\"a}nomen "Suffosion" in erster Linie ein Problem, das auf der Partikelebene untersucht werden muss. Die Homogenit{\"a}t der Kornzusammensetzung der Erdstoffe fi ndet explizit keine Rolle in den verf{\"u}gbaren Kriterien und die aktuellen internationalen Forschungsaktivit{\"a}ten zeigen, dass haupts{\"a}chlich weitere empirische Ans{\"a}tze entwickelt werden. Eingesetzte Methoden F{\"u}r die analytische Beschreibung von suffosiven Materialtransportprozessen in weitgestuften Erdstoffen unter Ber{\"u}cksichtigung der Homogenit{\"a}tseffekte, muss das Ph{\"a}nomen auf der Partikelebene beschrieben werden. Dies setzt drei Arbeitsschritte und Teilziele voraus: i) Die Kenntnis und Beschreibung der Gef{\"u}gestruktur ii) Beschreibung und Dimensionierung eines repr{\"a}sentativen Volumens iii) Konstruktion einer homogenen Packung f{\"u}r beliebige Korngr{\"o}ßßenverteilungslinien und Quantifizierung des vorhandenen Homogenit{\"a}tsgrads. Die granularen Packungen wurden sowohl experimentell als auch numerisch anhand sequentieller Mischversuche (SFT) untersucht. In einer stochastisch homogenen Packung werden der Anteil der skelettbildenden und der mobilen Fraktionen identifi ziert und ein Bereich als Trenndurchmesser, der Skelett und mobile Feinteile abgrenzt, bestimmt. Dadurch kann die Gef{\"u}gestruktur in suffosiv und nicht suffosive Gruppen klassifi ziert werden. Der experimentelle Ansatz wurde numerisch mittels Diskreter Element Methode (DEM) simuliert, um die Kontaktkr{\"a}fte und Anzahl der Nachbarn f{\"u}r verschiedene Bodenfraktionen (Skelett und bis zu gewissen Bereichen auch die F{\"u}llung) zu finden. Das kleinste repr{\"a}sentative Volumen (REV) f{\"u}r solch eine Bodenpackung wird numerisch bestimmt. Eine Methode zur Festlegung der relevanten Skala zur Quantifi zierung der Homogenit{\"a}t wurde vorgeschlagen. Als Bindeglied wurden 2D-Aufnahmen der experimentell oder numerisch erzeugten Packungen angefertigt, um mit Methoden der digitalen Bildverarbeitung die relevanten Kennwerte der Packung und die Anzahl der skelettbildenden Partikel zu ermitteln. Die erfassten Oberfl{\"a}chen dienen der statistischen Analyse der r{\"a}umlichen Streuung skeletviitbildender Partikel. Anhand der Berechnung der Varianz k{\"o}nnen die unterschiedlichen Parameter miteinander verglichen werden. Eine Varianz von Null bedeutet totale Homogenit{\"a}t. Ein Programm wurde in MATLAB geschrieben, um die Bildanalyse und die Varianzkalkulationen anhand unterschiedlicher Eingangsparameter durchzuf{\"u}hren. Ein analytisch beschreibbares Packungsmodell wird vorgeschlagen, um Homogenit{\"a}t und REV mit Suffosion in Verbindung zu bringen. Basierend auf diesem Modell wird ein Suffosionskriterium entwerfen, das in der Lage ist die Masse des ausgesp{\"u}lten Materials aus einem weitgestuften Boden zu prognostizieren. Wesentliche Ergebnisse Suffosion ist ein Ph{\"a}nomen der Partikelskala und der Partikeltransport ist abh{\"a}ngig von der Partikelanordnung. Die Zusammensetzung der skelettbildenden Partikel bestimmt die Eigenschaft des Porenraums. Die charakteristischen Parameter der Bodenstruktur eines weitgestuften Bodens wurden anhand sequentieller Mischversuche (SFT) festgestellt. Dadurch kann ein weitgestufter Boden in suffosiv oder nicht-suffosiv eingestuft werden. Das granulare Material formt ein Skelett, wenn die ben{\"o}tigte Mindestmasse oder das repr{\"a}{\"a}sentative Volumen erreicht wird. Dies ist eine notwendige Bedingung f{\"u}r die weiteren Untersuchungen. Diese Mindestmasse bzw. das repr{\"a}sentatives Volumen wurde numerisch mittels DEM Simulationen ermittelt. Eine statistische Methode f{\"u}r die Quantifi zierung der Homogenit{\"a}t f{\"u}r 2D-Aufnahmen in Abh{\"a}ngigkeit der Gr{\"o}ße des repr{\"a}sentativen Volumens wurde vorgeschlagen. Diese Methode wurde f{\"u}r komplexe stochastisch homogene, segregierte sowie f{\"u}r homogene Gitter-Packungen getestet. Die Ergebnisse sind vergleichbar mit dem bekannten Verfahren des Voronoi-Diagramms. Der Vorteil dieser Methode ist, dass viele Parameter ber{\"u}cksichtigt und in den Code integriert werden k{\"o}nnen. Eine in-situ Versuchsmethode f{\"u}r die Quantifi zierung der Homogenit{\"a}t wurde vorgeschlagen. Dar{\"u}ber hinaus wurde gezeigt, dass der lockerste und der dichteste Zustand eines weitgestuften Bodens, welcher gem{\"a}ß den Standardrichtlinien ermittelt werden kann, nicht die ultimativen Zust{\"a}nde sind. Die ultimativen Zust{\"a}nde k{\"o}nnen durch die vorgeschlagene Probenvorbereitung ermittelt werden. Ein homogenes Packungsmodell f{\"u}r weitgestufte B{\"o}den mit dominanter Grobmatrix wurde vorgestellt. Die Idee dieses Packungsmodells basiert auf der immer wiederkehrenden Natur der Homogenit{\"a}t und des Segregationsprozesses. Dieses Modell wurde durch Suffosionsversuche getestet und validiert. Basierend auf dem vorgeschlagenen Packungsmodell wurde eine neue experimentelle Methode zur qualitativen Beurteilung der Suffosionsanf{\"a}lligkeit vorgestellt. Ein neues analytisches Suffosionskriterium, basierend auf dem vorgeschlagenen Packungsmodel unter Ber{\"u}cksichtigung der Homogenit{\"a}t im REV wurde entworfen. Damit k{\"o}nnen die mobilen sowie suffosiven Fraktionen eines weitgestuften Bodens ermittelt werden.}, subject = {Homogenit{\"a}t}, language = {en} } @misc{Jahn, type = {Master Thesis}, author = {Jahn, Rosa}, title = {Evaluation von Nutzerbed{\"u}rfnissen in Wohngeb{\"a}uden unter Ber{\"u}cksichtigung hygrothermischer Messdaten}, doi = {10.25643/bauhaus-universitaet.1875}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20130320-18758}, school = {Bauhaus-Universit{\"a}t Weimar}, abstract = {Evaluation von Nutzerbed{\"u}rfnissen in Wohngeb{\"a}uden unter Ber{\"u}cksichtigung hygrothermischer Messdaten}, subject = {Raumklima}, language = {de} } @article{Aguinaga, author = {Aguinaga, Jos{\´e} Guillermo De}, title = {Error in prediction due to data type availability in a coupled hydro-mechanical model}, series = {Electronic Journal of Geotechnical Engineering}, journal = {Electronic Journal of Geotechnical Engineering}, doi = {10.25643/bauhaus-universitaet.3117}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170413-31170}, pages = {2459 -- 2471}, abstract = {Different types of data provide different type of information. The present research analyzes the error on prediction obtained under different data type availability for calibration. The contribution of different measurement types to model calibration and prognosis are evaluated. A coupled 2D hydro-mechanical model of a water retaining dam is taken as an example. Here, the mean effective stress in the porous skeleton is reduced due to an increase in pore water pressure under drawdown conditions. Relevant model parameters are identified by scaled sensitivities. Then, Particle Swarm Optimization is applied to determine the optimal parameter values and finally, the error in prognosis is determined. We compare the predictions of the optimized models with results from a forward run of the reference model to obtain the actual prediction errors. The analyses presented here were performed calibrating the hydro-mechanical model to 31 data sets of 100 observations of varying data types. The prognosis results improve when using diversified information for calibration. However, when using several types of information, the number of observations has to be increased to be able to cover a representative part of the model domain. For an analysis with constant number of observations, a compromise between data type availability and domain coverage proves to be the best solution. Which type of calibration information contributes to the best prognoses could not be determined in advance. The error in model prognosis does not depend on the error in calibration, but on the parameter error, which unfortunately cannot be determined in inverse problems since we do not know its real value. The best prognoses were obtained independent of calibration fit. However, excellent calibration fits led to an increase in prognosis error variation. In the case of excellent fits; parameters' values came near the limits of reasonable physical values more often. To improve the prognoses reliability, the expected value of the parameters should be considered as prior information on the optimization algorithm.}, subject = {Sensitivit{\"a}tsanalyse}, language = {en} } @phdthesis{Alexander, author = {Alexander, Anne}, title = {Quantitative Erfassung von Risiken und Simulation ihrer Auswirkungen auf den Verlauf eines Bauprojektes}, doi = {10.25643/bauhaus-universitaet.2051}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20130927-20514}, school = {Bauhaus-Universit{\"a}t Weimar}, pages = {171}, abstract = {Das Bauwesen hat sich in den letzten Jahren durch die Globalisierung des Marktes verbunden mit einer verst{\"a}rkten Nutzung moderner Technologien stark gewandelt. Die Planung und die Durchf{\"u}hrung von Bauvorhaben werden zunehmend komplexer und sind mit erh{\"o}hten Risiken verbunden. Geld- und Zeitressourcen werden bei einem immer h{\"a}rter werdenden Konkurrenzkampf knapper. Das Projektmanagement stellt L{\"o}sungsans{\"a}tze bereit, um Bauvorhaben auch unter erschwerten Bedingungen und erh{\"o}hten Risiken erfolgreich zum Abschluss zu bringen. Dabei hat ein systematisches Risikomanagement beginnend bei der Projektentwicklung bis zum Projektabschluss eine f{\"u}r den Projekterfolg entscheidende Bedeutung. Ziel der Arbeit ist es, eine quantitative Risikoerfassung f{\"u}r Projektmanager als professionelle Bauherrenvertretung und die Simulation der Risikoauswirkungen auf den Verlauf eines Projektes w{\"a}hrend der Planungs- und Bauphase zu erm{\"o}glichen. Mit Hilfe eines abstrakten Modells soll eine differenzierte, praxisnahe Simulation durchf{\"u}hrbar sein, die die verschiedenen Arten der Leistungs- und Kostenentstehung widerspiegelt. Parallel dazu soll die Beschreibung von Risiken so abstrahiert werden, dass beliebige Risiken quantitativ erfassbar und anschließend ihre Auswirkungen inklusive m{\"o}gliche Gegenmaßnahmen in das Modell integrierbar sind. Anhand zweier Beispiele werden die unterschiedlichen Einsatzm{\"o}glichkeiten der quantitativen Erfassung von Projektrisiken und der anschließenden Simulation ihrer Auswirkungen aufgezeigt. Bei dem ersten Beispiel, einem realen, bereits abgeschlossenen Schieneninfrastrukturprojekt, wird die Wirksamkeit einer vorbeugenden Maßnahme gegen ein Projektrisiko untersucht. Im zweiten Beispiel wird ein Planspielansatz zur praxisnahen Aus- und Weiterbildung von Projektmanagern entwickelt. Inhalt des Planspiels ist die Planung und Errichtung eines privatfinanzierten, {\"o}ffentlichen Repr{\"a}sentationsbaus mit teilweiser Fremdnutzung.}, subject = {Risiko}, language = {de} } @article{Bargstaedt, author = {Bargst{\"a}dt, Hans-Joachim}, title = {Challenges of BIM for Construction Site Operations}, series = {Procedia Engineering}, journal = {Procedia Engineering}, doi = {10.1016/j.proeng.2015.08.123}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170413-31218}, pages = {52 -- 59}, abstract = {Building Information Modeling is a powerful tool for the design and for a consistent set of data in a virtual storage. For the application in the phases of realization and on site it needs further development. The paper describes main challenges and main features, which will help the development of software to better service the needs of construction site managers}, subject = {Building Information Modeling}, language = {en} } @inproceedings{KieselEngelsVoelker, author = {Kiesel, Gerd and Engels, Merit and V{\"o}lker, Conrad}, title = {Energetische Transformation im l{\"a}ndlichen Raum - Aufbau eines prozessorientierten Entwicklungs- und Moderationsmodells}, series = {Schriftenreihe des Fachgebiets Bauphysik/Energetische Geb{\"a}udeoptimierung}, booktitle = {Schriftenreihe des Fachgebiets Bauphysik/Energetische Geb{\"a}udeoptimierung}, editor = {Kornadt, Oliver and Carrigan, Svenja and Hofmann, Markus and V{\"o}lker, Conrad}, publisher = {Eigenverlag Technische Universit{\"a}t Kaiserslautern}, address = {Kaiserslautern}, isbn = {978-3-95974-176-7}, issn = {2363-8206}, doi = {10.25643/bauhaus-universitaet.4656}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20220617-46566}, pages = {3}, abstract = {Kleine Kommunen im l{\"a}ndlichen Raum sind aufgrund ihrer oft eingeschr{\"a}nkten personellen und finanziellen Kapazit{\"a}ten bisher eher sporadisch in den Themenfeldern Energieeffizienz und Erneuerbare Energien aktiv. Immer wieder stellt sich daher Frage, wie die Klimaschutzstrategien des Bundes und der L{\"a}nder dort mit dem verf{\"u}gbaren Personal kosteng{\"u}nstig realisierbar sind. Vor diesem Hintergrund wird ein Werkzeug entwickelt, mit dessen Hilfe der aktive Einstieg in diese Thematik mit geringen Aufwand und {\"u}berwiegend barrierefrei m{\"o}glich ist. Der Aufbau eines prozessorientierten Entwicklungs- und Moderationsmodells zur Erprobung und Umsetzung bezahlbarer Handlungsoptionen f{\"u}r Energieeinsparungen und effizienten Energieeinsatz im {\"u}berwiegend l{\"a}ndlichen gepr{\"a}gten Raum ist der Schwerpunkt der Softwarel{\"o}sung. Kommunen werden mit deren Hilfe in die Lage versetzt, in die notwendigen Prozesse der Energie- und W{\"a}rmewende einzusteigen. Dabei soll der modulare Aufbau die regul{\"a}ren Schritte notwendiger (integrierter) Planungsprozesse nicht vollst{\"a}ndig ersetzen. Vielmehr k{\"o}nnen innerhalb der Online-Anwendung - {\"u}berwiegend automatisiert - konkrete Maßnahmenvorschl{\"a}ge erstellt werden, die ein solides Fundament der k{\"u}nftigen energetischen Entwicklung der Kommunen darstellen. F{\"u}r eine gezielte Validierung der Ergebnisse und der Ableitung potentieller Maßnahmen werden f{\"u}r die Erprobung Modellkommunen in Th{\"u}ringen, Bayern und Hessen als Reallabore einbezogen. Das Tool steht bisher zun{\"a}chst nur den beteiligten Modellkommunen zur Verf{\"u}gung. Die entwickelte Softwarel{\"o}sung soll k{\"u}nftig Schritt f{\"u}r Schritt allen interessierten Kommunen mit diversen Hilfsmitteln und einer Vielzahl anderer praktischer Bestandteile zur Verf{\"u}gung gestellt werden.}, subject = {Modellierung}, language = {de} } @article{VoelkerBeckmannKoehlmannetal., author = {V{\"o}lker, Conrad and Beckmann, Julia and Koehlmann, Sandra and Kornadt, Oliver}, title = {Occupant requirements in residential buildings - an empirical study and a theoretical model}, series = {Advances in Building Energy Research}, journal = {Advances in Building Energy Research}, number = {7 (1)}, doi = {10.25643/bauhaus-universitaet.3813}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20181015-38137}, pages = {35 -- 50}, abstract = {Occupant needs with regard to residential buildings are not well known due to a lack of representative scientific studies. To improve the lack of data, a large scale study was carried out using a Post Occupancy Evaluation of 1,416 building occupants. Several criteria describing the needs of occupants were evaluated with regard to their subjective level of relevance. Additionally, we investigated the degree to which deficiencies subjectively exist, and the degree to which occupants were able to accept them. From the data obtained, a hierarchy of criteria was created. It was found that building occupants ranked the physiological needs of air quality and thermal comfort the highest. Health hazards such as mould and contaminated building materials were unacceptable for occupants, while other deficiencies were more likely to be tolerated. Occupant satisfaction was also investigated. We found that most occupants can be classified as satisfied, although some differences do exist between different populations. To explain the relationship between the constructs of what we call relevance, acceptance, deficiency and satisfaction, we then created an explanatory model. Using correlation and regression analysis, the validity of the model was then confirmed by applying the collected data. The results of the study are both relevant in shaping further research and in providing guidance on how to maximize tenant satisfaction in real estate management.}, subject = {Post Occupancy Evaluation}, language = {en} } @article{MotraHildebrandDimmigOsburg, author = {Motra, Hem Bahadur and Hildebrand, J{\"o}rg and Dimmig-Osburg, Andrea}, title = {Assessment of strain measurement techniques to characterise mechanical properties of structural steel}, series = {Engineering Science and Technology, an International Journal}, journal = {Engineering Science and Technology, an International Journal}, doi = {10.1016/j.jestch.2014.07.006}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170425-31540}, pages = {260 -- 269}, abstract = {Strain measurement is important in mechanical testing. A wide variety of techniques exists for measuring strain in the tensile test; namely the strain gauge, extensometer, stress and strain determined by machine crosshead motion, Geometric Moire technique, optical strain measurement techniques and others. Each technique has its own advantages and disadvantages. The purpose of this study is to quantitatively compare the strain measurement techniques. To carry out the tensile test experiments for S 235, sixty samples were cut from the web of the I-profile in longitudinal and transverse directions in four different dimensions. The geometry of samples are analysed by 3D scanner and vernier caliper. In addition, the strain values were determined by using strain gauge, extensometer and machine crosshead motion. Three techniques of strain measurement are compared in quantitative manner based on the calculation of mechanical properties (modulus of elasticity, yield strength, tensile strength, percentage elongation at maximum force) of structural steel. A statistical information was used for evaluating the results. It is seen that the extensometer and strain gauge provided reliable data, however the extensometer offers several advantages over the strain gauge and crosshead motion for testing structural steel in tension. Furthermore, estimation of measurement uncertainty is presented for the basic material parameters extracted through strain measurement.}, subject = {Baustahl}, language = {en} } @article{ZhangWangLahmeretal., author = {Zhang, Chao and Wang, Cuixia and Lahmer, Tom and He, Pengfei and Rabczuk, Timon}, title = {A dynamic XFEM formulation for crack identification}, series = {International Journal of Mechanics and Materials in Design}, journal = {International Journal of Mechanics and Materials in Design}, pages = {427 -- 448}, abstract = {A dynamic XFEM formulation for crack identification}, subject = {Angewandte Mathematik}, language = {en} } @article{ZhangNanthakumarLahmeretal., author = {Zhang, Chao and Nanthakumar, S.S. and Lahmer, Tom and Rabczuk, Timon}, title = {Multiple cracks identification for piezoelectric structures}, series = {International Journal of Fracture}, journal = {International Journal of Fracture}, pages = {1 -- 19}, abstract = {Multiple cracks identification for piezoelectric structures}, subject = {Angewandte Mathematik}, language = {en} } @phdthesis{Link, author = {Link, Tim}, title = {Entwicklung und Untersuchung von alternativen Dicalciumsilicat-Bindern auf der Basis von alpha-C2SH}, doi = {10.25643/bauhaus-universitaet.3722}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20180205-37228}, school = {Bauhaus-Universit{\"a}t Weimar}, pages = {292}, abstract = {Um den Klimawandel zu begrenzen, m{\"u}ssen die CO2-Emissionen drastisch gesenkt werden [100]. Bis 2050 soll bei der Herstellung von Zement eine Einsparung um 51-60 \% auf 0,425-0,350 tCO2/tZement erfolgen [7]. Um dieses Ziel zu erreichen, sind alternative Bindemittelkonzepte notwendig [70]. Diese Arbeit widmet sich alternativen, hochreaktiven Dicalciumsilicat-Bindemitteln, die durch die thermische Aktivierung von α-Dicalcium-Silicat-Hydrat (α-C2SH) erzeugt werden. Das α-C2SH ist eine kristalline C S H-Phase, die im hydrothermalen Prozess, beispielsweise aus Branntkalk und Quarz, herstellbar ist. Die thermische Aktivierung kann bei sehr niedrigen Temperaturen erfolgen (>420 °C) und f{\"u}hrt zu einem Multiphasen-C2S-Binder. Als besonders reaktive Bestandteile k{\"o}nnen x-C2S und r{\"o}ntgenamorphe Anteile enthalten sein. Weiterhin k{\"o}nnen β C2S, γ C2S und Dellait (Ca6(SiO4)(Si2O7)(OH)2) entstehen. Im Rahmen der Arbeit wird zun{\"a}chst der Stand des Wissens zur Polymorphie und Hydratation von C2S zusammengefasst. Es werden bekannte C2S-basierte Bindemittelkonzepte vorgestellt und bewertet. Die Herstellung von C2S-Bindern wird experimentell im Labormaßstab untersucht. Dabei kommen unterschiedliche Autoklaven und ein Muffelofen zum Einsatz. Die Herstellungsparameter werden hinsichtlich Phasenbestand und Reaktivit{\"a}t optimiert. Die Bindemittel werden durch quantitative R{\"o}ntgen-Phasenanalyse (QXRD), Rasterelektronenmikroskopie (REM), N2-Adsorption (BET-Methode), Heliumpycnometer, Thermoanalyse (TGA/DSC) und 29Si-MAS- sowie 29Si-1H-CP/MAS-NMR-Spektroskopie charakterisiert. Das Hydratationsverhalten der Bindemittel wird vorrangig mithilfe von W{\"a}rmeflusskalorimetrie untersucht. Weiterhin werden in situ und ex situ XRD-, TGA/DSC- und REM-Untersuchungen durchgef{\"u}hrt. Anhand von zwei Bindemitteln wird die F{\"a}higkeit zur Erzielung hoher Festigkeiten demonstriert. Abschließend erfolgt eine Absch{\"a}tzung zu Energiebedarf und CO2-Emissionen f{\"u}r die Herstellung der untersuchten C2S-Binder. Die Ergebnisse zeigen, dass f{\"u}r eine hohe Reaktivit{\"a}t der Binder eine niedrige Brenntemperatur und ein geringer Wasserdampfpartialdruck w{\"a}hrend der thermischen Aktivierung entscheidend sind. Weiterhin muss das hydrothermal hergestellte α-C2SH eine m{\"o}glichst hohe spezifische Oberfl{\"a}che aufweisen. Diese Parameter beeinflussen den Phasenbestand und die phasenspezifische Reaktivit{\"a}t. Brenntemperaturen von ca. 420-500 °C f{\"u}hren zu hochreaktiven Bindern, die im Rahmen dieser Arbeit als Niedertemperatur-C2S-Binder bezeichnet werden. Temperaturen von ca. 600-800 °C f{\"u}hren zu Bindern mit geringerer Reaktivit{\"a}t, die im Rahmen dieser Arbeit als Hochtemperatur-C2S bezeichnet werden. H{\"o}here Brenntemperaturen (1000 °C) f{\"u}hren zu Bindemitteln, die innerhalb der ersten drei Tage keine hydraulische Aktivit{\"a}t zeigen. Die untersuchten Bindemittel k{\"o}nnen sehr hohe Reaktionsgeschwindigkeiten erreichen. Die W{\"a}rmeflusskalorimetrie deutet bei einigen Bindemitteln einen nahezu vollst{\"a}ndigen Umsatz innerhalb von drei Tagen an. Durch XRD wurde f{\"u}r einen Binder der vollst{\"a}ndige Verbrauch von x-C2S innerhalb von drei Tagen nachgewiesen. F{\"u}r einen mittels in-situ-XRD und W{\"a}rmeflusskalorimetrie untersuchten Binder wurde gezeigt, dass die Phasen vorrangig in der Reihenfolge r{\"o}ntgenamorph > x-C2S > β-C2S > γ-C2S hydratisieren. Hydratationsprodukte sind nadelige C S H-Phasen und Portlandit. Die Herstellung durch thermische Aktivierung von α-C2SH f{\"u}hrt zu tafeligen Bindemittelpartikeln, die teilweise Zwickelr{\"a}ume und Poren zwischen den einzelnen Partikeln einschließen. Um eine verarbeitbare Bindemittelpaste zu erzeugen, sind daher sehr hohe Wasser/Bindemittel-Werte (z. B. 1,4) erforderlich. Der Wasseranspruch kann durch Mahlung etwa auf das Niveau von Zement gesenkt werden. Die Druckfestigkeitsentwicklung wurde an zwei Niedertemperatur-C2S-Kompositbindern mit 40 \% Kalksteinmehl bzw. 40 \% H{\"u}ttensand untersucht. Aufgrund von theoretischen Betrachtungen zur Porosit{\"a}t in Abh{\"a}ngigkeit des w/b-Wertes wurde dieser auf 0,3 festgelegt. Durch Zugabe von PCE-Fließmittel wurde ein verarbeitbarer M{\"o}rtel erhalten. Die Festigkeitsentwicklung ist sehr schnell. Der Kalksteinmehl-Binder erreichte nach zwei Tagen 46 N/mm². Bis Tag 28 trat keine weitere Festigkeitssteigerung ein. Der H{\"u}ttensand-Binder erreichte nach zwei Tagen 62 N/mm². Durch die H{\"u}ttensandreaktion stieg die Festigkeit bis auf 85 N/mm² nach 28 Tagen an. F{\"u}r den Herstellungsprozess von Niedertemperatur-C2S-Binder wurden Energieverbr{\"a}uche und CO2-Emissionen abgesch{\"a}tzt. Es deutet sich an, dass, bezogen auf die Bindemittelmenge, keine wesentlichen Einsparungen im Vergleich zur Portlandzementherstellung m{\"o}glich sind. F{\"u}r die tats{\"a}chlichen Emissionen muss jedoch zus{\"a}tzlich die Leistungsf{\"a}higkeit der Bindemittel ber{\"u}cksichtigt werden. Die Leistungsf{\"a}higkeit kann als erforderliche Bindemittelmenge betrachtet werden, die je m³ Beton eingesetzt werden muss, um bestimmte Festigkeits-, Dauerhaftigkeits- und Verarbeitungseigenschaften zu erreichen. Aus verschiedenen Ver{\"o}ffentlichungen [94, 201, 206] wurde die These abgeleitet, dass die Leistungsf{\"a}higkeit eines Bindemittels maßgeblich von der C-S-H-Menge bestimmt wird, die w{\"a}hrend der Hydratation gebildet wird. Daher wird f{\"u}r NT-C2S-Binder eine außergew{\"o}hnlich hohe Leistungsf{\"a}higkeit erwartet. Auf Basis der Leistungsf{\"a}higkeitsthese verringern sich die abgesch{\"a}tzten CO2-Emissionen von NT-C2S-Bindern, sodass gegen{\"u}ber Portlandzement ein m{\"o}gliches Einsparpotenzial von 42 \% ermittelt wurde.}, subject = {Belit}, language = {de} } @article{NguyenTuanLahmerDatchevaetal., author = {Nguyen-Tuan, Long and Lahmer, Tom and Datcheva, Maria and Stoimenova, Eugenia and Schanz, Tom}, title = {A novel parameter identification approach for buffer elements involving complex coupled thermo-hydro-mechanical analyses}, series = {Computers and Geotechnics}, journal = {Computers and Geotechnics}, pages = {23 -- 32}, abstract = {A novel parameter identification approach for buffer elements involving complex coupled thermo-hydro-mechanical analyses}, subject = {Angewandte Mathematik}, language = {en} } @article{VuBacLahmerZhuangetal., author = {Vu-Bac, N. and Lahmer, Tom and Zhuang, Xiaoying and Nguyen-Thoi, T. and Rabczuk, Timon}, title = {A software framework for probabilistic sensitivity analysis for computationally expensive models}, series = {Advances in Engineering Software}, journal = {Advances in Engineering Software}, pages = {19 -- 31}, abstract = {A software framework for probabilistic sensitivity analysis for computationally expensive models}, subject = {Angewandte Mathematik}, language = {en} } @article{KnabeDatchevaLahmeretal., author = {Knabe, Tina and Datcheva, Maria and Lahmer, Tom and Cotecchia, F. and Schanz, Tom}, title = {Identification of constitutive parameters of soil using an optimization strategy and statistical analysis}, series = {Computers and Geotechnics}, journal = {Computers and Geotechnics}, pages = {143 -- 157}, abstract = {Identification of constitutive parameters of soil using an optimization strategy and statistical analysis}, subject = {Angewandte Mathematik}, language = {en} } @article{NanthakumarLahmerZhuangetal., author = {Nanthakumar, S.S. and Lahmer, Tom and Zhuang, Xiaoying and Park, Harold S. and Rabczuk, Timon}, title = {Topology optimization of piezoelectric nanostructures}, series = {Journal of the Mechanics and Physics of Solids}, journal = {Journal of the Mechanics and Physics of Solids}, pages = {316 -- 335}, abstract = {Topology optimization of piezoelectric nanostructures}, subject = {Angewandte Mathematik}, language = {en} } @article{SteinLahmerBock, author = {Stein, Peter and Lahmer, Tom and Bock, Sebastian}, title = {Synthese und Analyse von gekoppelten Modellen im konstruktiven Ingenieurbau}, series = {Bautechnik}, journal = {Bautechnik}, pages = {8 -- 11}, abstract = {Synthese und Analyse von gekoppelten Modellen im konstruktiven Ingenieurbau}, subject = {Angewandte Mathematik}, language = {de} } @article{LahmerKnabeNikullaetal., author = {Lahmer, Tom and Knabe, Tina and Nikulla, Susanne and Reuter, Markus}, title = {Bewertungsmethoden f{\"u}r Modelle des konstruktiven Ingenieurbaus}, series = {Bautechnik}, journal = {Bautechnik}, pages = {60 -- 64}, abstract = {Bewertungsmethoden f{\"u}r Modelle des konstruktiven Ingenieurbaus}, subject = {Angewandte Mathematik}, language = {de} } @article{LahmerIlgLerch, author = {Lahmer, Tom and Ilg, J. and Lerch, Reinhard}, title = {Variance-based sensitivity analyses of piezoelectric models}, series = {Computer Modeling in Engineering \& Sciences}, journal = {Computer Modeling in Engineering \& Sciences}, pages = {105 -- 126}, abstract = {Variance-based sensitivity analyses of piezoelectric models}, subject = {Angewandte Mathematik}, language = {en} } @article{Lahmer, author = {Lahmer, Tom}, title = {Optimal experimental design for nonlinear ill-posed problems applied to gravity dams}, series = {Inverse Problems}, journal = {Inverse Problems}, abstract = {Optimal experimental design for nonlinear ill-posed problems applied to gravity dams}, subject = {Angewandte Mathematik}, language = {en} } @article{NguyenVinhBakarMsekhetal., author = {Nguyen-Vinh, H. and Bakar, I. and Msekh, Mohammed Abdulrazzak and Song, Jeong-Hoon and Muthu, Jacob and Zi, Goangseup and Le, P. and Bordas, St{\´e}phane Pierre Alain and Simpson, R. and Natarajan, S. and Lahmer, Tom and Rabczuk, Timon}, title = {Extended Finite Element Method for Dynamic Fracture of Piezo-Electric Materials}, series = {Engineering Fracture Mechanics}, journal = {Engineering Fracture Mechanics}, doi = {10.1016/j.engfracmech.2012.04.025}, pages = {19 -- 31}, abstract = {We present an extended finite element formulation for dynamic fracture of piezo-electric materials. The method is developed in the context of linear elastic fracture mechanics. It is applied to mode I and mixed mode-fracture for quasi-steady cracks. An implicit time integration scheme is exploited. The results are compared to results obtained with the boundary element method and show excellent agreement.}, subject = {Angewandte Mathematik}, language = {en} } @article{NguyenTuanKoenkeBettziecheetal., author = {Nguyen-Tuan, Long and K{\"o}nke, Carsten and Bettzieche, Volker and Lahmer, Tom}, title = {Numerical modeling and validation for 3D coupled-nonlinear thermo-hydro-mechanical problems in masonry dams}, series = {Computers \& Structures}, journal = {Computers \& Structures}, pages = {143 -- 154}, abstract = {Numerical modeling and validation for 3D coupled-nonlinear thermo-hydro-mechanical problems in masonry dams}, subject = {Angewandte Mathematik}, language = {en} } @article{GhorashiLahmerBagherzadehetal., author = {Ghorashi, Seyed Shahram and Lahmer, Tom and Bagherzadeh, Amir Saboor and Zi, Goangseup and Rabczuk, Timon}, title = {A stochastic computational method based on goal-oriented error estimation for heterogeneous geological materials}, series = {Engineering Geology}, journal = {Engineering Geology}, abstract = {A stochastic computational method based on goal-oriented error estimation for heterogeneous geological materials}, subject = {Angewandte Mathematik}, language = {en} } @article{NanthakumarLahmerZhuangetal., author = {Nanthakumar, S.S. and Lahmer, Tom and Zhuang, Xiaoying and Zi, Goangseup and Rabczuk, Timon}, title = {Detection of material interfaces using a regularized level set method in piezoelectric structures}, series = {Inverse Problems in Science and Engineering}, journal = {Inverse Problems in Science and Engineering}, pages = {153 -- 176}, abstract = {Detection of material interfaces using a regularized level set method in piezoelectric structures}, subject = {Angewandte Mathematik}, language = {en} } @article{AchenbachLahmerMorgenthal, author = {Achenbach, Marcus and Lahmer, Tom and Morgenthal, Guido}, title = {Global Sensitivity Analysis of Reinforced Concrete Walls Subjected to Standard Fire - A Comparison of Methods}, series = {14th International Probabilistic Workshop}, journal = {14th International Probabilistic Workshop}, pages = {97 -- 106}, abstract = {Global Sensitivity Analysis of Reinforced Concrete Walls Subjected to Standard Fire—A Comparison of Methods}, subject = {Angewandte Mathematik}, language = {en} } @article{LahmerBockHildebrandetal., author = {Lahmer, Tom and Bock, Sebastian and Hildebrand, J{\"o}rg and G{\"u}rlebeck, Klaus}, title = {Non-destructive identification of residual stresses in steel under thermal loadings}, series = {Inverse Problems in Science and Engineering}, journal = {Inverse Problems in Science and Engineering}, pages = {1 -- 17}, abstract = {Non-destructive identification of residual stresses in steel under thermal loadings}, subject = {Angewandte Mathematik}, language = {en} } @article{GoebelLahmerOsburg, author = {G{\"o}bel, Luise and Lahmer, Tom and Osburg, Andrea}, title = {Uncertainty analysis in multiscale modeling of concrete based on continuum micromechanics}, series = {European Journal of Mechanics-A/Solids}, journal = {European Journal of Mechanics-A/Solids}, abstract = {Uncertainty analysis in multiscale modeling of concrete based on continuum micromechanics}, subject = {Angewandte Mathematik}, language = {en} } @article{AreiasRabczuk, author = {Areias, Pedro and Rabczuk, Timon}, title = {Finite strain fracture of plates and shells with configurational forces and edge rotation}, series = {International Journal for Numerical Methods in Engineering}, journal = {International Journal for Numerical Methods in Engineering}, abstract = {Finite strain fracture of plates and shells with configurational forces and edge rotation}, subject = {Angewandte Mathematik}, language = {en} } @article{MackeHiguchi, author = {Macke, M. and Higuchi, Shoko}, title = {Optimizing maintenance interventions for deteriorating structures using cost-benefit criteria}, series = {Journal of Structural Engineering}, journal = {Journal of Structural Engineering}, pages = {925 -- 934}, abstract = {Optimizing maintenance interventions for deteriorating structures using cost-benefit criteria}, subject = {Angewandte Mathematik}, language = {en} } @article{FaridmehrTahirLahmer, author = {Faridmehr, Iman and Tahir, Mamood Md. and Lahmer, Tom}, title = {Classification System for Semi-Rigid Beam-to-Column Connections}, series = {LATIN AMERICAN JOURNAL OF SOLIDS AND STRUCTURES 11}, journal = {LATIN AMERICAN JOURNAL OF SOLIDS AND STRUCTURES 11}, doi = {10.1590/1679-78252595}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170401-30988}, pages = {2152 -- 2175}, abstract = {The current study attempts to recognise an adequate classification for a semi-rigid beam-to-column connection by investigating strength, stiffness and ductility. For this purpose, an experimental test was carried out to investigate the moment-rotation (M-theta) features of flush end-plate (FEP) connections including variable parameters like size and number of bolts, thickness of end-plate, and finally, size of beams and columns. The initial elastic stiffness and ultimate moment capacity of connections were determined by an extensive analytical procedure from the proposed method prescribed by ANSI/AISC 360-10, and Eurocode 3 Part 1-8 specifications. The behaviour of beams with partially restrained or semi-rigid connections were also studied by incorporating classical analysis methods. The results confirmed that thickness of the column flange and end-plate substantially govern over the initial rotational stiffness of of flush end-plate connections. The results also clearly showed that EC3 provided a more reliable classification index for flush end-plate (FEP) connections. The findings from this study make significant contributions to the current literature as the actual response characteristics of such connections are non-linear. Therefore, such semirigid behaviour should be used to for an analysis and design method.}, subject = {Tragf{\"a}higkeit}, language = {en} } @article{ZhaoLuZhangetal., author = {Zhao, Jun-Hua and Lu, Lixin and Zhang, Zhiliang and Guo, Wanlin and Rabczuk, Timon}, title = {Continuum modeling of the cohesive energy for the interfaces between _lms, spheres, coats and substrates}, series = {Computational Materials Science}, journal = {Computational Materials Science}, pages = {432 -- 438}, abstract = {Continuum modeling of the cohesive energy for the interfaces between _lms, spheres, coats and substrates}, subject = {Angewandte Mathematik}, language = {en} } @article{BenZhaoZhangetal., author = {Ben, S. and Zhao, Jun-Hua and Zhang, Yancheng and Rabczuk, Timon}, title = {The interface strength and debonding for composite structures: review and recent developments}, series = {Composite Structures}, journal = {Composite Structures}, abstract = {The interface strength and debonding for composite structures: review and recent developments}, subject = {Angewandte Mathematik}, language = {en} } @article{ZhaoJiaWeietal., author = {Zhao, Jun-Hua and Jia, Yue and Wei, Ning and Rabczuk, Timon}, title = {Binding energy and mechanical stability of two parallel and crossing carbon nanotubes}, series = {Journal of Applied Mechanics}, journal = {Journal of Applied Mechanics}, abstract = {Binding energy and mechanical stability of two parallel and crossing carbon nanotubes}, subject = {Angewandte Mathematik}, language = {en} } @article{KumarSinghMishraetal., author = {Kumar, S. and Singh, I. and Mishra, B.K. and Rabczuk, Timon}, title = {Modeling and Simulation of Kinked Cracks by Virtual Node XFEM}, series = {Computer Methods in Applied Mechanics and Engineering}, journal = {Computer Methods in Applied Mechanics and Engineering}, pages = {1425 -- 1466}, abstract = {Modeling and Simulation of Kinked Cracks by Virtual Node XFEM}, subject = {Angewandte Mathematik}, language = {en} } @article{NanthakumarLahmerRabczuk, author = {Nanthakumar, S.S. and Lahmer, Tom and Rabczuk, Timon}, title = {Detection of flaws in piezoelectric structures using extended FEM}, series = {International Journal for Numerical Methods in Engineering}, journal = {International Journal for Numerical Methods in Engineering}, pages = {373 -- 389}, abstract = {Detection of flaws in piezoelectric structures using extended FEM}, subject = {Angewandte Mathematik}, language = {en} } @article{ZhaoWeiFanetal., author = {Zhao, Jun-Hua and Wei, Ning and Fan, Z. and Jiang, Jin-Wu and Rabczuk, Timon}, title = {Mechanical properties of three types of carbon allotropes}, series = {Nanotechnology}, journal = {Nanotechnology}, abstract = {Mechanical properties of three types of carbon allotropes}, subject = {Angewandte Mathematik}, language = {en} } @article{AreiasRabczukDiasdaCostaetal., author = {Areias, Pedro and Rabczuk, Timon and Dias-da-Costa, D. and Piresh, E.B.}, title = {Implicit solutions with consistent additive and multiplicative components}, series = {Finite Elements in Analysis and Design}, journal = {Finite Elements in Analysis and Design}, doi = {10.1016/j.finel.2012.03.007}, pages = {15 -- 31}, abstract = {This work describes an algorithm and corresponding software for incorporating general nonlinear multiple-point equality constraints in a implicit sparse direct solver. It is shown that direct addressing of sparse matrices is possible in general circumstances, circumventing the traditional linear or binary search for introducing (generalized) constituents to a sparse matrix. Nested and arbitrarily interconnected multiple-point constraints are introduced by processing of multiplicative constituents with a built-in topological ordering of the resulting directed graph. A classification of discretization methods is performed and some re-classified problems are described and solved under this proposed perspective. The dependence relations between solution methods, algorithms and constituents becomes apparent. Fracture algorithms can be naturally casted in this framework. Solutions based on control equations are also directly incorporated as equality constraints. We show that arbitrary constituents can be used as long as the resulting directed graph is acyclic. It is also shown that graph partitions and orderings should be performed in the innermost part of the algorithm, a fact with some peculiar consequences. The core of our implicit code is described, specifically new algorithms for direct access of sparse matrices (by means of the clique structure) and general constituent processing. It is demonstrated that the graph structure of the second derivatives of the equality constraints are cliques (or pseudo-elements) and are naturally included as such. A complete algorithm is presented which allows a complete automation of equality constraints, avoiding the need of pre-sorting. Verification applications in four distinct areas are shown: single and multiple rigid body dynamics, solution control and computational fracture.}, subject = {Angewandte Mathematik}, language = {en} } @article{JiangRabczukPark, author = {Jiang, Jin-Wu and Rabczuk, Timon and Park, Harold S.}, title = {A Stillinger-Weber Potential for Single-Layer Black Phosphorus, and the Importance of Cross-Pucker Interactions for Negative Poisson's Ratio and Edge Stress-Induced Bending}, series = {Nanoscale}, journal = {Nanoscale}, doi = {10.1039/C4NR07341J}, abstract = {The distinguishing structural feature of single-layered black phosphorus is its puckered structure, which leads to many novel physical properties. In this work, we first present a new parameterization of the Stillinger-Weber potential for single-layered black phosphorus. In doing so, we reveal the importance of a cross-pucker interaction term in capturing its unique mechanical properties, such as a negative Poisson's ratio. In particular, we show that the cross-pucker interaction enables the pucker to act as a re-entrant hinge, which expands in the lateral direction when it is stretched in the longitudinal direction. As a consequence, single-layered black phosphorus has a negative Poisson's ratio in the direction perpendicular to the atomic plane. As an additional demonstration of the impact of the cross-pucker interaction, we show that it is also the key factor that enables capturing the edge stress-induced bending of single-layered black phosphorus that has been reported in ab initio calculations.}, subject = {Angewandte Mathematik}, language = {en} } @article{HiguchiMacke, author = {Higuchi, Shoko and Macke, M.}, title = {Cost-benefit based optimization of maintenance interventions for deteriorating structures}, series = {Structural Engineering/Earthquake Engineering}, journal = {Structural Engineering/Earthquake Engineering}, pages = {131 -- 147}, abstract = {Cost-benefit based optimization of maintenance interventions for deteriorating structures}, subject = {Angewandte Mathematik}, language = {en} } @article{TalebiSilaniRabczuk, author = {Talebi, Hossein and Silani, Mohammad and Rabczuk, Timon}, title = {Concurrent Multiscale Modelling of Three Dimensional Crack and Dislocation Propagation}, series = {Advances in Engineering Software}, journal = {Advances in Engineering Software}, pages = {82 -- 92}, abstract = {Concurrent Multiscale Modelling of Three Dimensional Crack and Dislocation Propagation}, subject = {Angewandte Mathematik}, language = {en} } @article{XuMourrainGalligoetal., author = {Xu, G. and Mourrain, B. and Galligo, A. and Rabczuk, Timon}, title = {High-quality construction of analysis-suitable trivariate NURBS solids by reparameterization methods}, series = {Computational Mechanics}, journal = {Computational Mechanics}, abstract = {High-quality construction of analysis-suitable trivariate NURBS solids by reparameterization methods}, subject = {Angewandte Mathematik}, language = {en} } @article{PhanDaoNguyenXuanThaiHoangetal., author = {Phan-Dao, H. and Nguyen-Xuan, Hung and Thai-Hoang, C. and Nguyen-Thoi, T. and Rabczuk, Timon}, title = {An edge-based smoothed finite element method for analysis of laminated composite plates}, series = {International Journal of Computational Methods}, journal = {International Journal of Computational Methods}, abstract = {An edge-based smoothed finite element method for analysis of laminated composite plates}, subject = {Angewandte Mathematik}, language = {en} } @article{SilaniZiaeiRadTalebietal., author = {Silani, Mohammad and Ziaei-Rad, S. and Talebi, Hossein and Rabczuk, Timon}, title = {A Semi-Concurrent Multiscale Approach for Modeling Damage in Nanocomposites}, series = {Theoretical and Applied Fracture Mechanics}, journal = {Theoretical and Applied Fracture Mechanics}, abstract = {A Semi-Concurrent Multiscale Approach for Modeling Damage in Nanocomposites}, subject = {Angewandte Mathematik}, language = {en} } @article{AmaniBagherzadehRabczuk, author = {Amani, Jafar and Bagherzadeh, Amir Saboor and Rabczuk, Timon}, title = {Error estimate and adaptive refinement in Mixed Discrete Least Squares Meshless method}, series = {Mathematical Problems in Engineering}, journal = {Mathematical Problems in Engineering}, abstract = {Error estimate and adaptive refinement in Mixed Discrete Least Squares Meshless method}, subject = {Angewandte Mathematik}, language = {en} } @phdthesis{Giebson, author = {Giebson, Colin}, title = {Die Alkali-Kiesels{\"a}ure-Reaktion in Beton f{\"u}r Fahrbahndecken und Flugbetriebsfl{\"a}chen unter Einwirkung alkalihaltiger Enteisungsmittel}, isbn = {978-3-00-044366-4 (Druckversion)}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20131217-20916}, school = {Bauhaus-Universit{\"a}t Weimar}, pages = {208}, abstract = {Das Hauptziel der Arbeit war es zu kl{\"a}ren, ob alkalihaltige Enteisungsmittel eine Alkali-Kiesels{\"a}ure-Reaktion (AKR) ausl{\"o}sen und/oder beschleunigen k{\"o}nnen und was die dabei ggf. zugrunde liegenden Mechanismen sind. Die Untersuchungen dazu ergaben, dass die auf Verkehrsfl{\"a}chen eingesetzten alkalihaltigen Enteisungsmittel auf Basis von Natriumchlorid (Fahrbahndecken) bzw. auf Basis der Alkaliacetate und -formiate (Flugbetriebsfl{\"a}chen) den Ablauf einer AKR in Betonen mit alkalireaktiven Gesteinsk{\"o}rnungen ausl{\"o}sen und mitunter stark beschleunigen k{\"o}nnen. Dabei nimmt die AKR-f{\"o}rdernde Wirkung der Enteisungsmittel in der Reihenfolge Natriumchlorid - Alkaliacetate - Alkaliformiate erheblich zu. Es zeigte sich, dass im Fall der Alkaliacetate und -formiate nicht allein die Zufuhr von Alkalien von Bedeutung ist, sondern dass es außerdem zu einer Freisetzung von OH-Ionen aus dem Portlandit und folglich zu einem Anstieg des pH-Wertes in der Porenl{\"o}sung kommt. Dadurch wird der Angriff auf alkalireaktives SiO2 in Gesteinsk{\"o}rnungen verst{\"a}rkt und der Ablauf einer AKR beschleunigt. Unter {\"a}ußerer NaCl-Zufuhr kommt es hingegen nicht zu einem Anstieg des pH-Wertes, was der Grund f{\"u}r die weniger stark AKR-f{\"o}rdernde Wirkung von NaCl ist. Von Bedeutung sind hier die zugef{\"u}hrten Na-Ionen und offenbar ein sich andeutender, direkter Einfluss von NaCl auf das SiO2-L{\"o}severhalten. Sind pH-Wert und Na-Konzentration in der Porenl{\"o}sung ausreichend hoch, wird sich thermodynamisch bedingt AKR-Gel bilden. Die Bildung von FRIEDEL'schem Salz ist dabei nur eine Begleiterscheinung, aber keine Voraussetzung f{\"u}r den Ablauf einer AKR unter {\"a}ußerer NaCl-Zufuhr. Es zeigte sich weiter, dass sich mit der FIB-Klimawechsellagerung als Performance-Pr{\"u}fung das AKR-Sch{\"a}digungspotential von Betonen f{\"u}r Fahrbahndecken und Flugbetriebsfl{\"a}chen zuverl{\"a}ssig beurteilen l{\"a}sst. Die Vorteile der FIB-Klimawechsellagerung liegen in der Pr{\"u}fung kompletter, projektspezifischer Betonzusammensetzungen unter Beachtung aller praxisrelevanten klimatischen Einwirkungen und vor allem in der Ber{\"u}cksichtigung einer {\"a}ußeren Alkalizufuhr. Innerhalb von 36 Wochen kann das AKR-Sch{\"a}digungspotential einer Betonzusammensetzung f{\"u}r eine Nutzungsdauer von 20-30 Jahren in der Praxis sicher beurteilt werden.}, subject = {Beton}, language = {de} } @article{JiangWangRabczuk, author = {Jiang, Jin-Wu and Wang, Bing-Shen and Rabczuk, Timon}, title = {Acoustic and breathing phonon modes in bilayer graphene with Moire-acute patterns}, series = {Applied Physics Letters}, journal = {Applied Physics Letters}, doi = {10.1063/1.4735246}, abstract = {The lattice dynamics properties are investigated for twisting bilayer graphene. There are big jumps for the inter-layer potential at twisting angle θ=0° and 60°, implying the stability of Bernal-stacking and the instability of AA-stacking structures, while a long platform in [8,55]° indicates the ease of twisting bilayer graphene in this wide angle range. Significant frequency shifts are observed for the z breathing mode around θ=0° and 60°, while the frequency is a constant in a wide range [8,55]°. Using the z breathing mode, a mechanical nanoresonator is proposed to operate on a robust resonant frequency in terahertz range.}, subject = {Angewandte Mathematik}, language = {en} } @article{GhasemiBrighentiZhuangetal., author = {Ghasemi, Hamid and Brighenti, Roberto and Zhuang, Xiaoying and Muthu, Jacob and Rabczuk, Timon}, title = {Optimum fiber content and distribution in fiber-reinforced solids using a reliability and NURBS based sequential optimization approach}, series = {Structural and Multidisciplinary Optimization}, journal = {Structural and Multidisciplinary Optimization}, pages = {99 -- 112}, abstract = {Optimum _ber content and distribution in _ber-reinforced solids using a reliability and NURBS based sequential optimization approach}, subject = {Angewandte Mathematik}, language = {en} } @article{AreiasRabczukCesardeSaetal., author = {Areias, Pedro and Rabczuk, Timon and Cesar de Sa, J.M. and Jorge, R.N.}, title = {A semi-implicit _nite strain shell algorithm using in-plane strains based on least-squares}, series = {Computational Mechanics}, journal = {Computational Mechanics}, abstract = {A semi-implicit _nite strain shell algorithm using in-plane strains based on least-squares}, subject = {Angewandte Mathematik}, language = {en} } @article{ZhaoJiangWangetal., author = {Zhao, Jiyun and Jiang, Jin-Wu and Wang, L. and Guo, Wanlin and Rabczuk, Timon}, title = {Coarse-grained potentials of single-walled carbon nanotubes}, series = {Journal of the Mechanics and Physics of Solids}, journal = {Journal of the Mechanics and Physics of Solids}, abstract = {Coarse-grained potentials of single-walled carbon nanotubes}, subject = {Angewandte Mathematik}, language = {en} } @article{JiangWangRabczuk, author = {Jiang, Jin-Wu and Wang, Bing-Shen and Rabczuk, Timon}, title = {Why twisting angles are diverse in graphene Moir'e patterns?}, series = {Journal of Applied Physics}, journal = {Journal of Applied Physics}, abstract = {Why twisting angles are diverse in graphene Moir'e patterns?}, subject = {Angewandte Mathematik}, language = {en} } @article{JiangZhaoZhouetal., author = {Jiang, Jin-Wu and Zhao, Jun-Hua and Zhou, K. and Rabczuk, Timon}, title = {Superior thermal conductivity and extremely high mechanical strength in polyethylene chains from ab initio calculation}, series = {Journal of Applied Physics}, journal = {Journal of Applied Physics}, doi = {10.1063/1.4729489}, abstract = {The upper limit of the thermal conductivity and the mechanical strength are predicted for the polyethylene chain, by performing the ab initio calculation and applying the quantum mechanical non-equilibrium Green's function approach. Specially, there are two main findings from our calculation: (1) the thermal conductivity can reach a high value of 310 Wm-1 K-1 in a 100 nm polyethylene chain at room temperature and the thermal conductivity increases with the length of the chain; (2) the Young's modulus in the polyethylene chain is as high as 374.5 GPa, and the polyethylene chain can sustain 32.85\%±0.05\% (ultimate) strain before undergoing structural phase transition into gaseous ethylene.}, subject = {Angewandte Mathematik}, language = {en} } @article{LutherKoenke, author = {Luther, Torsten and K{\"o}nke, Carsten}, title = {Coupled cohesive zone representations from 3D quasicontinuum simulation on aluminum grain boundaries}, series = {International Journal for Multiscale Computational Engineering}, journal = {International Journal for Multiscale Computational Engineering}, abstract = {Coupled cohesive zone representations from 3D quasicontinuum simulation on aluminum grain boundaries}, subject = {Angewandte Mathematik}, language = {en} } @article{AreiasRabczukBarbosa, author = {Areias, Pedro and Rabczuk, Timon and Barbosa, J.I.}, title = {The extended unsymmetric frontal solution for multiple-point constraints}, series = {Engineering Computations}, journal = {Engineering Computations}, abstract = {The extended unsymmetric frontal solution for multiple-point constraints}, subject = {Angewandte Mathematik}, language = {en} } @article{UngerTeughelsDeRoeck, author = {Unger, J{\"o}rg F. and Teughels, A. and De Roeck, G.}, title = {Damage detection of a prestressed concrete beam using modal strains}, series = {Journal of Structural Engineering}, journal = {Journal of Structural Engineering}, pages = {1456 -- 1463}, abstract = {Damage detection of a prestressed concrete beam using modal strains}, subject = {Angewandte Mathematik}, language = {en} } @article{VuBacSilaniLahmeretal., author = {Vu-Bac, N. and Silani, Mohammad and Lahmer, Tom and Zhuang, Xiaoying and Rabczuk, Timon}, title = {A unified framework for stochastic predictions of Young's modulus of clay/epoxy nanocomposites (PCNs)}, series = {Computational Materials Science}, journal = {Computational Materials Science}, pages = {520 -- 535}, abstract = {A unified framework for stochastic predictions of Young's modulus of clay/epoxy nanocomposites (PCNs)}, subject = {Angewandte Mathematik}, language = {en} } @article{NanthakumarLahmerZhuangetal., author = {Nanthakumar, S.S. and Lahmer, Tom and Zhuang, Xiaoying and Zi, Goangseup and Rabczuk, Timon}, title = {Detection of material interfaces using a regularized level set method in piezoelectric structures}, series = {Inverse Problems in Science and Engineering}, journal = {Inverse Problems in Science and Engineering}, abstract = {Detection of material interfaces using a regularized level set method in piezoelectric structures}, subject = {Angewandte Mathematik}, language = {en} } @article{VuBacRafieeZhuangetal., author = {Vu-Bac, N. and Rafiee, Roham and Zhuang, Xiaoying and Lahmer, Tom and Rabczuk, Timon}, title = {Uncertainty quantification for multiscale modeling of polymer nanocomposites with correlated parameters}, series = {Composites Part B: Engineering}, journal = {Composites Part B: Engineering}, pages = {446 -- 464}, abstract = {Uncertainty quantification for multiscale modeling of polymer nanocomposites with correlated parameters}, subject = {Angewandte Mathematik}, language = {en} } @article{VuBacLahmerZhangetal., author = {Vu-Bac, N. and Lahmer, Tom and Zhang, Yancheng and Zhuang, Xiaoying and Rabczuk, Timon}, title = {Stochastic predictions of interfacial characteristic of polymeric nanocomposites (PNCs)}, series = {Composites Part B Engineering}, journal = {Composites Part B Engineering}, pages = {80 -- 95}, abstract = {Stochastic predictions of interfacial characteristic of polymeric nanocomposites (PNCs)}, subject = {Angewandte Mathematik}, language = {en} } @article{ZhangRen, author = {Zhang, Yongzheng and Ren, Huilong}, title = {Implicit implementation of the nonlocal operator method: an open source code}, series = {Engineering with computers}, volume = {2022}, journal = {Engineering with computers}, publisher = {Springer}, address = {London}, doi = {10.1007/s00366-021-01537-x}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20220216-45930}, pages = {1 -- 35}, abstract = {In this paper, we present an open-source code for the first-order and higher-order nonlocal operator method (NOM) including a detailed description of the implementation. The NOM is based on so-called support, dual-support, nonlocal operators, and an operate energy functional ensuring stability. The nonlocal operator is a generalization of the conventional differential operators. Combined with the method of weighed residuals and variational principles, NOM establishes the residual and tangent stiffness matrix of operate energy functional through some simple matrix without the need of shape functions as in other classical computational methods such as FEM. NOM only requires the definition of the energy drastically simplifying its implementation. The implementation in this paper is focused on linear elastic solids for sake of conciseness through the NOM can handle more complex nonlinear problems. The NOM can be very flexible and efficient to solve partial differential equations (PDEs), it's also quite easy for readers to use the NOM and extend it to solve other complicated physical phenomena described by one or a set of PDEs. Finally, we present some classical benchmark problems including the classical cantilever beam and plate-with-a-hole problem, and we also make an extension of this method to solve complicated problems including phase-field fracture modeling and gradient elasticity material.}, subject = {Strukturmechanik}, language = {en} } @article{JoshiHildebrandAloraieretal., author = {Joshi, Suraj and Hildebrand, J{\"o}rg and Aloraier, Abdulkareem S. and Rabczuk, Timon}, title = {Characterization of material properties and heat source parameters in welding simulation of two overlapping beads on a substrate plate}, series = {Computational Materials Science}, journal = {Computational Materials Science}, doi = {10.1016/j.commatsci.2012.11.029}, pages = {559 -- 565}, abstract = {This paper presents several aspects of characterization of welding heat source parameters in Goldak's double ellipsoidal model using Sysweld simulation of welding of two overlapping beads on a substrate steel plate. The overlap percentages ranged from 40\% to 80\% in increments of 10\%. The new material properties of the fused metal were characterized using Weldware and their continuous cooling transformation curves. The convective and radiative heat transfer coefficients as well as the cooling time t8/5 were estimated using numerical formulations from relevant standards. The effects of the simulation geometry and mesh discretization were evaluated in terms of the factor F provided in Sysweld. Eventually, the parameters of Goldak's double ellipsoidal heat source model were determined for the welding simulation of overlapping beads on the plate and the simulated bead geometry, extent of the molten pool and the HAZ were compared with the macrographs of cross-sections of the experimental weldments. The results showed excellent matching, thus verifying this methodology for determination of welding heat source parameters.}, subject = {Angewandte Mathematik}, language = {en} } @article{JiangRabczuk, author = {Jiang, Jin-Wu and Rabczuk, Timon}, title = {Mechanical Oscillation of Kinked Silicon Nanowires: a Natural Nanoscale Spring}, series = {Applied Physics Letters}, journal = {Applied Physics Letters}, abstract = {Mechanical Oscillation of Kinked Silicon Nanowires: a Natural Nanoscale Spring}, subject = {Angewandte Mathematik}, language = {en} } @phdthesis{Vu, author = {Vu, Bac Nam}, title = {Stochastic uncertainty quantification for multiscale modeling of polymeric nanocomposites}, doi = {10.25643/bauhaus-universitaet.2555}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20160322-25551}, school = {Bauhaus-Universit{\"a}t Weimar}, pages = {265}, abstract = {Nanostructured materials are extensively applied in many fields of material science for new industrial applications, particularly in the automotive, aerospace industry due to their exceptional physical and mechanical properties. Experimental testing of nanomaterials is expensive, timeconsuming,challenging and sometimes unfeasible. Therefore,computational simulations have been employed as alternative method to predict macroscopic material properties. The behavior of polymeric nanocomposites (PNCs) are highly complex. The origins of macroscopic material properties reside in the properties and interactions taking place on finer scales. It is therefore essential to use multiscale modeling strategy to properly account for all large length and time scales associated with these material systems, which across many orders of magnitude. Numerous multiscale models of PNCs have been established, however, most of them connect only two scales. There are a few multiscale models for PNCs bridging four length scales (nano-, micro-, meso- and macro-scales). In addition, nanomaterials are stochastic in nature and the prediction of macroscopic mechanical properties are influenced by many factors such as fine-scale features. The predicted mechanical properties obtained by traditional approaches significantly deviate from the measured values in experiments due to neglecting uncertainty of material features. This discrepancy is indicated that the effective macroscopic properties of materials are highly sensitive to various sources of uncertainty, such as loading and boundary conditions and material characteristics, etc., while very few stochastic multiscale models for PNCs have been developed. Therefore, it is essential to construct PNC models within the framework of stochastic modeling and quantify the stochastic effect of the input parameters on the macroscopic mechanical properties of those materials. This study aims to develop computational models at four length scales (nano-, micro-, meso- and macro-scales) and hierarchical upscaling approaches bridging length scales from nano- to macro-scales. A framework for uncertainty quantification (UQ) applied to predict the mechanical properties of the PNCs in dependence of material features at different scales is studied. Sensitivity and uncertainty analysis are of great helps in quantifying the effect of input parameters, considering both main and interaction effects, on the mechanical properties of the PNCs. To achieve this major goal, the following tasks are carried out: At nano-scale, molecular dynamics (MD) were used to investigate deformation mechanism of glassy amorphous polyethylene (PE) in dependence of temperature and strain rate. Steered molecular dynamics (SMD)were also employed to investigate interfacial characteristic of the PNCs. At mico-scale, we developed an atomistic-based continuum model represented by a representative volume element (RVE) in which the SWNT's properties and the SWNT/polymer interphase are modeled at nano-scale, the surrounding polymer matrix is modeled by solid elements. Then, a two-parameter model was employed at meso-scale. A hierarchical multiscale approach has been developed to obtain the structure-property relations at one length scale and transfer the effect to the higher length scales. In particular, we homogenized the RVE into an equivalent fiber. The equivalent fiber was then employed in a micromechanical analysis (i.e. Mori-Tanaka model) to predict the effective macroscopic properties of the PNC. Furthermore, an averaging homogenization process was also used to obtain the effective stiffness of the PCN at meso-scale. Stochastic modeling and uncertainty quantification consist of the following ingredients: - Simple random sampling, Latin hypercube sampling, Sobol' quasirandom sequences, Iman and Conover's method (inducing correlation in Latin hypercube sampling) are employed to generate independent and dependent sample data, respectively. - Surrogate models, such as polynomial regression, moving least squares (MLS), hybrid method combining polynomial regression and MLS, Kriging regression, and penalized spline regression, are employed as an approximation of a mechanical model. The advantage of the surrogate models is the high computational efficiency and robust as they can be constructed from a limited amount of available data. - Global sensitivity analysis (SA) methods, such as variance-based methods for models with independent and dependent input parameters, Fourier-based techniques for performing variance-based methods and partial derivatives, elementary effects in the context of local SA, are used to quantify the effects of input parameters and their interactions on the mechanical properties of the PNCs. A bootstrap technique is used to assess the robustness of the global SA methods with respect to their performance. In addition, the probability distribution of mechanical properties are determined by using the probability plot method. The upper and lower bounds of the predicted Young's modulus according to 95 \% prediction intervals were provided. The above-mentioned methods study on the behaviour of intact materials. Novel numerical methods such as a node-based smoothed extended finite element method (NS-XFEM) and an edge-based smoothed phantom node method (ES-Phantom node) were developed for fracture problems. These methods can be used to account for crack at macro-scale for future works. The predicted mechanical properties were validated and verified. They show good agreement with previous experimental and simulations results.}, subject = {Polymere}, language = {en} } @article{NguyenTuanLahmerDatchevaetal., author = {Nguyen-Tuan, Long and Lahmer, Tom and Datcheva, Maria and Schanz, Tom}, title = {Global and local sensitivity analyses for coupled thermo-hydro-mechanical problems}, series = {International Journal for Numerical and Analytical Methods in Geomechanics}, journal = {International Journal for Numerical and Analytical Methods in Geomechanics}, abstract = {Global and local sensitivity analyses for coupled thermo-hydro-mechanical problems}, subject = {Angewandte Mathematik}, language = {en} } @article{JiangParkRabczuk, author = {Jiang, Jin-Wu and Park, Harold S. and Rabczuk, Timon}, title = {Enhancing the mass sensitivity of graphene nanoresonators via nonlinear oscillations: The effective strain mechanism}, series = {Nanotechnology}, journal = {Nanotechnology}, abstract = {Enhancing the mass sensitivity of graphene nanoresonators via nonlinear oscillations: The effective strain mechanism}, subject = {Angewandte Mathematik}, language = {en} } @article{MsekhSargadoJamshidianetal., author = {Msekh, Mohammed Abdulrazzak and Sargado, M. and Jamshidian, M. and Areias, Pedro and Rabczuk, Timon}, title = {ABAQUS implementation of phase_field model for brittle fracture}, series = {Computational Materials Science}, journal = {Computational Materials Science}, pages = {472 -- 484}, abstract = {ABAQUS implementation of phase_field model for brittle fracture}, subject = {Angewandte Mathematik}, language = {en} } @article{ZhaoLuRabczuk, author = {Zhao, Jiyun and Lu, Lixin and Rabczuk, Timon}, title = {The tensile and shear failure behavior dependence on chain length and temperature in amorphous polymers}, series = {Computational Materials Science}, journal = {Computational Materials Science}, pages = {567 -- 572}, abstract = {The tensile and shear failure behavior dependence on chain length and temperature in amorphous polymers}, subject = {Angewandte Mathematik}, language = {en} } @article{HiguchiMacke, author = {Higuchi, Shoko and Macke, M.}, title = {Cost-benefit based optimization of maintenance interventions for deteriorating structures}, series = {Doboku Gakkai Ronbunshuu A}, journal = {Doboku Gakkai Ronbunshuu A}, pages = {727 -- 743}, abstract = {Cost-benefit based optimization of maintenance interventions for deteriorating structures}, subject = {Angewandte Mathematik}, language = {en} } @article{HaefnerEckardtLutheretal., author = {H{\"a}fner, Stefan and Eckardt, Stefan and Luther, Torsten and K{\"o}nke, Carsten}, title = {Mesoscale modeling of concrete: Geometry and numerics}, series = {Computers and Structures}, journal = {Computers and Structures}, pages = {450 -- 461}, abstract = {Mesoscale modeling of concrete: Geometry and numerics}, subject = {Angewandte Mathematik}, language = {en} } @article{HauckLahmerKaltenbacher, author = {Hauck, A. and Lahmer, Tom and Kaltenbacher, Manfred}, title = {Enhanced homogenization technique for magnetomechanical systems using the generalized finite element method}, series = {COMPEL: The international journal for computation and mathematics in electrical and electronic engineering}, journal = {COMPEL: The international journal for computation and mathematics in electrical and electronic engineering}, pages = {935 -- 947}, abstract = {Enhanced homogenization technique for magnetomechanical systems using the generalized finite element method}, subject = {Angewandte Mathematik}, language = {en} } @article{KaltenbacherLahmerMohretal., author = {Kaltenbacher, Barbara and Lahmer, Tom and Mohr, Marcus and Kaltenbacher, Manfred}, title = {PDE based determination of piezoelectric material tensors}, series = {European Journal of Applied Mathematics}, journal = {European Journal of Applied Mathematics}, doi = {10.25643/bauhaus-universitaet.3595}, pages = {383 -- 416}, abstract = {PDE based determination of piezoelectric material tensors.}, subject = {Angewandte Mathematik}, language = {en} } @article{LahmerKoenkeBettzieche, author = {Lahmer, Tom and K{\"o}nke, Carsten and Bettzieche, Volker}, title = {Optimale Positionierung von Messeinrichtungen an Staumauern zur Bauwerks{\"u}berwachung}, series = {WASSERWIRTSCHAFT}, journal = {WASSERWIRTSCHAFT}, pages = {16 -- 16}, abstract = {Optimale Positionierung von Messeinrichtungen an Staumauern zur Bauwerks{\"u}berwachung}, subject = {Angewandte Mathematik}, language = {de} } @article{LahmerKoenkeBettzieche, author = {Lahmer, Tom and K{\"o}nke, Carsten and Bettzieche, Volker}, title = {Optimal positioning of sensors for the monitoring of water dams}, series = {WASSERWIRTSCHAFT}, journal = {WASSERWIRTSCHAFT}, pages = {16 -- 19}, abstract = {Optimal positioning of sensors for the monitoring of water dams}, subject = {Angewandte Mathematik}, language = {de} } @article{NguyenThoiPhungVanRabczuketal., author = {Nguyen-Thoi, T. and Phung-Van, P. and Rabczuk, Timon and Nguyen-Xuan, Hung and Le-Van, C.}, title = {An application of the ES-FEM in solid domain for dynamic analysis of 2D fluid-solid interaction problems}, series = {International Journal of Computational Methods}, journal = {International Journal of Computational Methods}, abstract = {An application of the ES-FEM in solid domain for dynamic analysis of 2D fluid-solid interaction problems}, subject = {Angewandte Mathematik}, language = {en} } @article{MarzbanLahmer, author = {Marzban, Samira and Lahmer, Tom}, title = {Conceptual implementation of the variance-based sensitivity analysis for the calculation of the first-order effects}, series = {Journal of Statistical Theory and Practice}, journal = {Journal of Statistical Theory and Practice}, pages = {589 -- 611}, abstract = {Conceptual implementation of the variance-based sensitivity analysis for the calculation of the first-order effects}, subject = {Angewandte Mathematik}, language = {en} } @article{NanthakumarLahmerRabczuk, author = {Nanthakumar, S.S. and Lahmer, Tom and Rabczuk, Timon}, title = {Detection of multiple flaws in piezoelectric structures using XFEM and level sets}, series = {International Journal for Numerical Methods in Engineering}, journal = {International Journal for Numerical Methods in Engineering}, pages = {960}, abstract = {Detection of multiple flaws in piezoelectric structures using XFEM and level sets}, subject = {Angewandte Mathematik}, language = {en} } @article{AnitescuJiaZhangetal., author = {Anitescu, Cosmin and Jia, Yue and Zhang, Yongjie and Rabczuk, Timon}, title = {An isogeometric collocation method using superconvergent points}, series = {Computer Methods in Applied Mechanics and Engineer-ing}, journal = {Computer Methods in Applied Mechanics and Engineer-ing}, pages = {1073 -- 1097}, abstract = {An isogeometric collocation method using superconvergent points}, subject = {Angewandte Mathematik}, language = {en} } @article{AchenbachLahmerMorgenthal, author = {Achenbach, Marcus and Lahmer, Tom and Morgenthal, Guido}, title = {Identification of the thermal properties of concrete for the temperature calculation of concrete slabs and columns subjected to a standard fire—Methodology and proposal for simplified formulations}, series = {Fire Safety Journal 87}, journal = {Fire Safety Journal 87}, doi = {10.1016/j.firesaf.2016.12.003}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170331-30929}, pages = {80 -- 86}, abstract = {The fire resistance of concrete members is controlled by the temperature distribution of the considered cross section. The thermal analysis can be performed with the advanced temperature dependent physical properties provided by 5EN6 1992-1-2. But the recalculation of laboratory tests on columns from 5TU6 Braunschweig shows, that there are deviations between the calculated and measured temperatures. Therefore it can be assumed, that the mathematical formulation of these thermal properties could be improved. A sensitivity analysis is performed to identify the governing parameters of the temperature calculation and a nonlinear optimization method is used to enhance the formulation of the thermal properties. The proposed simplified properties are partly validated by the recalculation of measured temperatures of concrete columns. These first results show, that the scatter of the differences from the calculated to the measured temperatures can be reduced by the proposed simple model for the thermal analysis of concrete.}, subject = {Sensitivit{\"a}tsanalyse}, language = {en} } @article{ZhaoJiangJiaetal., author = {Zhao, Jun-Hua and Jiang, Jin-Wu and Jia, Yue and Guo, Wanlin and Rabczuk, Timon}, title = {A theoretical analysis of cohesive energy between carbon nanotubes, graphene and substrates}, series = {Carbon}, journal = {Carbon}, doi = {10.1016/j.carbon.2013.01.041}, pages = {108 -- 119}, abstract = {Explicit solutions for the cohesive energy between carbon nanotubes, graphene and substrates are obtained through continuum modeling of the van der Waals interaction between them. The dependence of the cohesive energy on their size, spacing and crossing angles is analyzed. Checking against full atom molecular dynamics calculations and available experimental results shows that the continuum solution has high accuracy. The equilibrium distances between the nanotubes, graphene and substrates with minimum cohesive energy are also provided explicitly. The obtained analytical solution should be of great help for understanding the interaction between the nanostructures and substrates, and designing composites and nanoelectromechanical systems.}, subject = {Angewandte Mathematik}, language = {en} } @article{LeNguyenXuanAskesetal., author = {Le, C.V. and Nguyen-Xuan, Hung and Askes, H. and Rabczuk, Timon and Nguyen-Thoi, T.}, title = {Computation of limit load using edge-based smoothed finite element method and second-order cone programming}, series = {International Journal of Computational Methods}, journal = {International Journal of Computational Methods}, abstract = {Computation of limit load using edge-based smoothed finite element method and second-order cone programming}, subject = {Angewandte Mathematik}, language = {en} } @article{NguyenThanhKiendlNguyenXuanetal., author = {Nguyen-Thanh, Nhon and Kiendl, J. and Nguyen-Xuan, Hung and W{\"u}chner, R. and Bletzinger, Kai-Uwe and Bazilevs, Yuri and Rabczuk, Timon}, title = {Rotation free isogeometric thin shell analysis using PHT-splines}, series = {Computer Methods in Applied Mechanics and Engineering}, journal = {Computer Methods in Applied Mechanics and Engineering}, pages = {3410 -- 3424}, abstract = {Rotation free isogeometric thin shell analysis using PHT-splines}, subject = {Angewandte Mathematik}, language = {en} } @article{SchraderKoenke, author = {Schrader, Kai and K{\"o}nke, Carsten}, title = {Distributed computing for the nonlinear analysis of multiphase composites}, series = {Advances in Engineering Software}, journal = {Advances in Engineering Software}, pages = {20 -- 32}, abstract = {Distributed computing for the nonlinear analysis of multiphase composites}, subject = {Angewandte Mathematik}, language = {en} } @phdthesis{Nowak, author = {Nowak, Saskia}, title = {Alterung von Calciumsulfatphasen : Physiko-chemisch bedingte Feuchteaufnahmen und Einfluss auf die Reaktivit{\"a}t}, isbn = {978-3-00-041328-5}, doi = {10.25643/bauhaus-universitaet.1873}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20130320-18731}, school = {Bauhaus-Universit{\"a}t Weimar}, pages = {155}, abstract = {Die Arbeit zeigt die wesentlichen Gr{\"u}nde auf, warum betahalbhydratreiche Niederbranntgipsbinder (industriell als Stuckgips bezeichnet) oft sehr unterschiedliche Eigenschaften aufweisen. Der Anteil an Halbhydrat, welches aus dem stark hygroskopischen Anhydrit III (A III) durch die Reaktion mit Luftfeuchtigkeit entsteht, stellt einen erheblichen, bislang vollkommen unbeachteten Einfluss dar. Dieses Halbhydrat aus A III zeigt andere Oberfl{\"a}cheneigenschaften und ein Reaktionsverhalten, das von frisch gebranntem Betahalbhydrat abweicht. Es zeigt sich, wie weitreichend der Einfluss physiko-chemischer Oberfl{\"a}chenprozesse wie Adsorption und Kondensation ist. Hierdurch wird nicht nur die Oberfl{\"a}chenenergie der Partikel abgebaut, sondern auch eine Verminderung der Hydratationsw{\"a}rme verursacht. Somit wirken sich physikalische Vorg{\"a}nge thermodynamisch aus. Einwirkende und resultierende Parameter einer Alterung wirken wie folgt {\"a}ußerst komplex zusammen: Die dominierenden Bindemitteleigenschaften Abbindeverhalten und Wasseranspruch ver{\"a}ndern sich durch eine Alterung sowohl aufgrund der Phasenumwandlungen als auch infolge der Ver{\"a}nderungen der Kristallite. Ebenso einflussreich ist die Ver{\"a}nderung der Oberfl{\"a}chencharakteristik. Die Auswirkung der Alterung auf die Reaktivit{\"a}t geht deutlich {\"u}ber den Abbau von Anhydrit III, die Dezimierung von abbindef{\"a}higem Material und die beschleunigende Wirkung von Alterungsdihydrat hinaus. Das Wachstum der Kristallite von Halbhydrat und die Verringerung der inneren Energie sowie die energetisch g{\"u}nstige spontane Beladung der Kristallgitterkan{\"a}le kleinster Anhydrit III-Kristallite mit dampff{\"o}rmigem Wasser m{\"u}ssen als maßgebliche Ursachen f{\"u}r die Abnahme der Reaktivit{\"a}t infolge der Alterung herausgestellt werden. Die Abnahme der spezifischen Oberfl{\"a}che und der Oberfl{\"a}chenenergie wirken sich außerdem auf den L{\"o}sungs- und den Hydratationsprozess aus. Der auf der Oberfl{\"a}che von Anhydrit III kristallisierte Anhydrit II wirkt sich auch nach der Umwandlung von A III in Halbhydrat l{\"o}sungshemmend aus. Infolge der alterungsbedingten Dihydratbildung, die bei anhaltender Feuchteeinwirkung einsetzt, wird diese Wirkung aufgehoben bzw. vermindert. Obgleich Dihydrat f{\"u}r seinen Beschleunigungseffekt bekannt ist, entfaltet Alterungsdihydrat infolge seiner besonderen Ausbildung innerhalb der wenige Molek{\"u}llagen umfassenden Kondenswasserschicht nur eine geringe keimbildende Wirkung. Eine wesentliche Erkenntnis betrifft den Bindungscharakter des {\"U}berst{\"o}chiometrischen Wassers. Diesbez{\"u}glich ist eine rein physikalische Bindung nachweisbar. Das in der Arbeit als st{\"a}rker adsorptiv gebunden bezeichnete Wasser kommt neben der Freien Feuchte ausschließlich bei Anwesenheit von Halbhydrat vor. Dieser Zusammenhang wird erstmalig hergestellt und mit Hilfe der kristallchemisch bedingten h{\"o}heren Oberfl{\"a}chenenergie von Halbhydrat erkl{\"a}rt.}, subject = {Alterung}, language = {de} } @article{LahmerNguyenTuanKoenkeetal., author = {Lahmer, Tom and Nguyen-Tuan, Long and K{\"o}nke, Carsten and Bettzieche, Volker}, title = {Thermo-hydro-mechanische 3-D-Simulation von Staumauern-Modellierung und Validierung}, series = {WASSERWIRTSCHAFT}, journal = {WASSERWIRTSCHAFT}, pages = {27 -- 30}, abstract = {Thermo-hydro-mechanische 3-D-Simulation von Staumauern-Modellierung und Validierung}, subject = {Angewandte Mathematik}, language = {de} } @article{AreiasRabczukCesardeSaetal., author = {Areias, Pedro and Rabczuk, Timon and Cesar de Sa, J.M. and Garcao, J.E.}, title = {Finite strain quadrilateral shell using least-squares _t of relative Lagrangian in-plane strains}, series = {Finite Elements in Analysis and Design}, journal = {Finite Elements in Analysis and Design}, pages = {26 -- 40}, abstract = {Finite strain quadrilateral shell using least-squares _t of relative Lagrangian in-plane strains}, subject = {Angewandte Mathematik}, language = {en} } @article{LahmerKaltenbacherSchulz, author = {Lahmer, Tom and Kaltenbacher, Barbara and Schulz, V.}, title = {Optimal measurement selection for piezoelectric material tensor identification}, series = {Inverse Problems in Science and Engineering}, journal = {Inverse Problems in Science and Engineering}, doi = {10.25643/bauhaus-universitaet.3593}, pages = {369 -- 387}, abstract = {Optimal measurement selection for piezoelectric material tensor identification.}, subject = {Angewandte Mathematik}, language = {en} } @article{Lahmer, author = {Lahmer, Tom}, title = {Modified Landweber iterations in a multilevel algorithm applied to inverse problems in piezoelectricity}, series = {Journal of Inverse and Ill-posed Problems}, journal = {Journal of Inverse and Ill-posed Problems}, pages = {585 -- 593}, abstract = {Modified Landweber iterations in a multilevel algorithm applied to inverse problems in piezoelectricity}, subject = {Angewandte Mathematik}, language = {en} } @article{GhasemiKerfridenBordasetal., author = {Ghasemi, Hamid and Kerfriden, Pierre and Bordas, St{\´e}phane Pierre Alain and Muthu, Jacob and Zi, Goangseup and Rabczuk, Timon}, title = {Interfacial shear stress optimization in sandwich beams with polymeric core using nonuniform distribution of reinforcing ingredients}, series = {Composite Structures}, journal = {Composite Structures}, pages = {221 -- 230}, abstract = {Interfacial shear stress optimization in sandwich beams with polymeric core using nonuniform distribution of reinforcing ingredients}, subject = {Angewandte Mathematik}, language = {en} } @article{ZhaoKouJiangetal., author = {Zhao, Jun-Hua and Kou, Liangzhi and Jiang, Jin-Wu and Rabczuk, Timon}, title = {Tension-induced phase transition of single-layer molybdenum disulphide (MoS2) at low temperatures}, series = {Nanotechnology}, journal = {Nanotechnology}, doi = {10.1088/0957-4484/25/29/295701}, abstract = {Tension-induced phase transition of single-layer molybdenum disulphide (MoS2) at low temperatures}, subject = {Angewandte Mathematik}, language = {en} } @article{JiaZhangRabczuk, author = {Jia, Yue and Zhang, Yongjie and Rabczuk, Timon}, title = {A Novel Dynamic Multilevel Technique for Image Registration}, series = {Computers and Mathematics with Applications}, journal = {Computers and Mathematics with Applications}, abstract = {A Novel Dynamic Multilevel Technique for Image Registration}, subject = {Angewandte Mathematik}, language = {en} } @article{AreiasRabczukQueirosdeMeloetal., author = {Areias, Pedro and Rabczuk, Timon and Queiros de Melo, F. J. M. and Cesar de Sa, J.M.}, title = {Coulomb frictional contact by explicit projection in the cone for _nite displacement quasi-static problems}, series = {Computational Mechanics}, journal = {Computational Mechanics}, pages = {57 -- 72}, abstract = {Coulomb frictional contact by explicit projection in the cone for _nite displacement quasi-static problems}, subject = {Angewandte Mathematik}, language = {en} }