@inproceedings{MotraDimmigOsburgHildebrand, author = {Motra, Hem Bahadur and Dimmig-Osburg, Andrea and Hildebrand, J{\"o}rg}, title = {UNCERTAINTY QUANTIFICATION IN CYCLIC CREEP PREDICTION OF CONCRETE}, series = {Digital Proceedings, International Conference on the Applications of Computer Science and Mathematics in Architecture and Civil Engineering : July 04 - 06 2012, Bauhaus-University Weimar}, booktitle = {Digital Proceedings, International Conference on the Applications of Computer Science and Mathematics in Architecture and Civil Engineering : July 04 - 06 2012, Bauhaus-University Weimar}, editor = {G{\"u}rlebeck, Klaus and Lahmer, Tom and Werner, Frank}, organization = {Bauhaus-Universit{\"a}t Weimar}, issn = {1611-4086}, doi = {10.25643/bauhaus-universitaet.2780}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170314-27803}, pages = {18}, abstract = {This paper presents a methodology for uncertainty quantification in cyclic creep analysis. Several models- , namely BP model, Whaley and Neville model, modified MC90 for cyclic loading and modified Hyperbolic function for cyclic loading are used for uncertainty quantification. Three types of uncertainty are included in Uncertainty Quantification (UQ): (i) natural variability in loading and materials properties; (ii) data uncertainty due to measurement errors; and (iii) modelling uncertainty and errors during cyclic creep analysis. Due to the consideration of all type of uncertainties, a measure for the total variation of the model response is achieved. The study finds that the BP, modified Hyperbolic and modified MC90 are best performing models for cyclic creep prediction in that order. Further, global Sensitivity Analysis (SA) considering the uncorrelated and correlated parameters is used to quantify the contribution of each source of uncertainty to the overall prediction uncertainty and to identifying the important parameters. The error in determining the input quantities and model itself can produce significant changes in creep prediction values. The variability influence of input random quantities on the cyclic creep was studied by means of the stochastic uncertainty and sensitivity analysis namely the Gartner et al. method and Saltelli et al. method. All input imperfections were considered to be random quantities. The Latin Hypercube Sampling (LHS) numerical simulation method (Monte Carlo type method) was used. It has been found by the stochastic sensitivity analysis that the cyclic creep deformation variability is most sensitive to the Elastic modulus of concrete, compressive strength, mean stress, cyclic stress amplitude, number of cycle, in that order.}, subject = {Angewandte Informatik}, language = {en} } @inproceedings{AlmamouGebhardtBocketal., author = {Almamou, Abd Albasset and Gebhardt, Thomas and Bock, Sebastian and Hildebrand, J{\"o}rg and Schwarz, Willfried}, title = {QUALITY CONTROL OF CONSTRUCTED MODELS USING 3D POINT CLOUD}, series = {Digital Proceedings, International Conference on the Applications of Computer Science and Mathematics in Architecture and Civil Engineering : July 20 - 22 2015, Bauhaus-University Weimar}, booktitle = {Digital Proceedings, International Conference on the Applications of Computer Science and Mathematics in Architecture and Civil Engineering : July 20 - 22 2015, Bauhaus-University Weimar}, editor = {G{\"u}rlebeck, Klaus and Lahmer, Tom}, organization = {Bauhaus-Universit{\"a}t Weimar}, issn = {1611-4086}, doi = {10.25643/bauhaus-universitaet.2794}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170314-27944}, pages = {9}, abstract = {Over the last decade, the technology of constructing buildings has been dramatically developed especially with the huge growth of CAD tools that help in modeling buildings, bridges, roads and other construction objects. Often quality control and size accuracy in the factory or on construction site are based on manual measurements of discrete points. These measured points of the realized object or a part of it will be compared with the points of the corresponding CAD model to see whether and where the construction element fits into the respective CAD model. This process is very complicated and difficult even when using modern measuring technology. This is due to the complicated shape of the components, the large amount of manually detected measured data and the high cost of manual processing of measured values. However, by using a modern 3D scanner one gets information of the whole constructed object and one can make a complete comparison against the CAD model. It gives an idea about quality of objects on the whole. In this paper, we present a case study of controlling the quality of measurement during the constructing phase of a steel bridge by using 3D point cloud technology. Preliminary results show that an early detection of mismatching between real element and CAD model could save a lot of time, efforts and obviously expenses.}, subject = {Angewandte Informatik}, language = {en} } @inproceedings{GoebelHildebrandWerner, author = {G{\"o}bel, Michael and Hildebrand, J{\"o}rg and Werner, Frank}, title = {NUMERISCHES MODELL F{\"U}R DIE SIMULATION EINER LASERSTRAHLSCHWEIßUNG VON QUARZGLAS}, editor = {G{\"u}rlebeck, Klaus and K{\"o}nke, Carsten}, organization = {Bauhaus-Universit{\"a}t Weimar}, doi = {10.25643/bauhaus-universitaet.2958}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170327-29589}, pages = {14}, abstract = {Ausgehend von den fundierten Erfahrungen, die f{\"u}r das Schweißen von verschiedensten Metallen vorliegen, wird an der Professur Stahlbau der Bauhaus-Universit{\"a}t Weimar ein neuartiges Verfahren zum CO2-Laserstrahlschweißen von Quarzglas numerisch untersucht. Dabei kommt die kommerzielle FE-Software SYSWELD® zum Einsatz. Die erforderlichen Versuche werden in Zusammenarbeit mit dem Institut f{\"u}r F{\"u}getechnik und Werkstoffpr{\"u}fung GmbH aus Jena realisiert. Die numerische Analyse wird eingesetzt, um geeignete Prozessparameter zu bestimmen und deren Auswirkungen auf die transienten thermischen und mechanischen Vorg{\"a}nge, die w{\"a}hrend des Schweißvorgangs ablaufen abzubilden. Um die aus der Simulation erhaltenen Aussagen zu {\"u}berpr{\"u}fen, ist es erforderlich, das Berechnungsmodell mittels Daten aus Versuchsschweißungen zu kalibrieren. Dabei sind die verwendeten Materialmodelle sowie die der Simulation zugrunde gelegten Materialkennwerte zu validieren. Es stehen verschiedene rheologische Berechnungsmodelle zur Auswahl, die die viskosen Materialeigenschaften des Glases abbilden. Dabei werden die drei mechanischen Grundelemente, die HOOKEsche Feder, der NEWTONsche D{\"a}mpfungszylinder und das ST.-VENANT-Element miteinander kombiniert. Die M{\"o}glichkeit, thermische und mechanische Vorg{\"a}nge innerhalb des Glases w{\"a}hrend des Schweißvorgangs und nach vollst{\"a}ndiger Abk{\"u}hlung, vorhersagen zu k{\"o}nnen, gestattet es den Schweißvorgang {\"u}ber eine Optimierung der Verfahrensparameter gezielt dahingehend zu beeinflussen, die Wirtschaftlichkeit des Schweißverfahrens zu verbessern, und ein zuverl{\"a}ssiges Schweißergebnis zu erhalten. Dabei k{\"o}nnen auch nur unter hohem experimentellen Aufwand durchf{\"u}hrbare Versuche simuliert werden, um eine Vorhersage zu treffen, ob es zweckm{\"a}ßig ist, den Versuch auch in der Praxis zu fahren. Dies f{\"u}hrt zu einer Reduzierung des experimentellen Aufwandes und damit zu einer Verk{\"u}rzung des Entwicklungszeitraumes f{\"u}r das angestrebte Verfahren.}, subject = {Architektur }, language = {de} } @inproceedings{HildebrandWudtkeWerner, author = {Hildebrand, J{\"o}rg and Wudtke, Idna and Werner, Frank}, title = {M{\"O}GLICHKEITEN DER MATHEMATISCHEN BESCHREIBUNG VON PHASENUMWANDLUNGEN IM STAHL BEI SCHWEIß- UND WIG-NACHBEHANDLUNGSPROZESSEN}, editor = {G{\"u}rlebeck, Klaus and K{\"o}nke, Carsten}, organization = {Bauhaus-Universit{\"a}t Weimar}, doi = {10.25643/bauhaus-universitaet.2968}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170327-29684}, pages = {13}, abstract = {In the final decades many scientists were occupied intensively with the change of materials during a process and their mathematical descriptions. The extensive and extensive analyses were supported by the advanced computer science. A mathematical description of the phase transformation is a condition for a realistic FE simulation of the state of microstructure. It is possible to simulate the temperature and stress field also in complex construction based on the state of microstructure. In the last years a great number of mathematical models were expanded to describe the transformation between different phases. For the development of the models for transformation kinetics it is practical to subdivide into isothermal and non-isothermal processes according to the thermal conditions. Some models for the description of the transformation with non-isothermal processes represent extensions for isothermal of processes. A part of parameters for the describing equations can be derived from the time-temperature-transformation diagrams in the literature. Furthermore the two possibilities of transformation are considered by different models - diffusion controlled and not diffusion controlled. The material-specific characteristics can be simulated during the transformation for each individual phase in a realistic FE analyses. Also new materials can be simulated after a modification of the parameters in the describing equations for the phase transformation. The effects in the temperature and stress field are a substantial reason for the investigation of the phase transformation during the welding and TIG-dressing processes.}, subject = {Architektur }, language = {de} }