TY - CHAP A1 - Nechytailo, Oleksandr A1 - Horokhov, Yevgen A1 - Kushchenko, Vladimir ED - Gürlebeck, Klaus ED - Lahmer, Tom ED - Werner, Frank T1 - ANALYSIS OF THE MODE OF DEFORMATION OF THE SUB-PULLEY STRUCTURES ON SHAFT SLOPING HEADGEAR STRUCTURES T2 - Digital Proceedings, International Conference on the Applications of Computer Science and Mathematics in Architecture and Civil Engineering : July 04 - 06 2012, Bauhaus-University Weimar N2 - A numerical analysis of the mode of deformation of the main load-bearing components of a typical frame sloping shaft headgear was performed. The analysis was done by a design model consisting of plane and solid finite elements, which were modeled in the program «LIRA». Due to the numerical results, the regularities of local stress distribution under a guide pulley bearing were revealed and parameters of a plane stress under both emergency and normal working loads were determined. In the numerical simulation, the guidelines to improve the construction of the joints of guide pulleys resting on sub-pulley frame-type structures were established. Overall, the results obtained are the basis for improving the engineering procedures of designing steel structures of shaft sloping headgear. KW - Angewandte Informatik KW - Angewandte Mathematik KW - Computerunterstütztes Verfahren Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20170314-27826 UR - http://euklid.bauing.uni-weimar.de/ikm2012 SN - 1611-4086 ER - TY - THES A1 - Karaki, Ghada T1 - Assessment of coupled models of bridges considering time-dependent vehicular loading N2 - Bridge vibration due to traffic loading has been a subject of extensive research in the last decades. The focus of such research has been to develop solution algorithms and investigate responses or behaviors of interest. However, proving the quality and reliability of the model output in structural engineering has become a topic of increasing importance. Therefore, this study is an attempt to extend concepts of uncertainty and sensitivity analyses to assess the dynamic response of a coupled model in bridge engineering considering time-dependent vehicular loading. A setting for the sensitivity analysis is proposed, which enables performing the sensitivity analysis considering random stochastic processes. The classical and proposed sensitivity settings are used to identify the relevant input parameters and models that have the most influence on the variance of the dynamic response. The sensitivity analysis exercises the model itself and extracts results without the need for measurements or reference solutions; however, it does not offer a means of ranking the coupled models studied. Therefore, concepts of total uncertainty are employed to rank the coupled models studied according to their fitness in describing the dynamic problem. The proposed procedures are applied in two examples to assess the output of coupled subsystems and coupled partial models in bridge engineering considering the passage of a heavy vehicle at various speeds. N2 - Brückenschwingungen infolge von Verkehrslasten sind seit mehreren Jahrzehnten Gegenstand intensiver Forschung. Im Fokus stand hierbei im Besonderen die Entwicklung von Lösungsalgorithmen zur Ermittlung des dynamischen Bauwerkverhaltens. Begleitet ist diese Entwicklung von der Frage nach der Qualität und Zuverlässigkeit dieser Modelle für den Gebrauch im konstruktiven Ingenieurbau. In diesem Zusammenhang werden in der vorliegenden Arbeit Konzepte der Unsicherheits- und Sensitivitätsanalyse erweitert, um das dynamische Bauwerkverhalten unter Berücksichtigung transienter Fahrzeuglasten bei gekoppelten Modellen des Brückenbaus zu bewerten. Bestehende Sensitivitätsanalysen werden ergänzt, um diese auch unter Berücksichtigung von stochastischen Prozessen durchführen zu können. Die klassische und die erweiterte Methode werden angewandt, um relevante Eingangsparameter sowie Partialmodelle mit wesentlichem Einfluss auf die Varianz der dynamischen Strukturantwort zu identifizieren. Die mit Hilfe der Sensitivitätsanalyse ermittelbaren Kennzahlen können ohne Bezug zu einer Referenzlösung in die Modellbewertung einfließen, allerdings ist es nicht möglich, die Modelle hinsichtlich der realitätsnahen Abbildung des dynamischen Problems zu bewerten. Um dies zu ermöglichen, wurden Konzepte der Gesamtunsicherheit verwendet. Die vorgestellten Methoden wurden auf zwei Beispiele angewandt, um die Ergebnisse von gekoppelten Subsystemen und gekoppelten Partialmodellen des Brückenbaus zu evaluieren. Hierbei handelt es sich um die Überfahrt von schweren Fahrzeugen mit verschiedenen Geschwindigkeiten. T3 - Schriftenreihe des DFG Graduiertenkollegs 1462 Modellqualitäten // Graduiertenkolleg Modellqualitäten - 5 KW - Ingenieurbau KW - bridge-vehicle interaction KW - random vibrations KW - sensitivity and uncertainty analysis Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20120402-15894 ER - TY - CHAP A1 - Jung, Bastian A1 - Morgenthal, Guido ED - Gürlebeck, Klaus ED - Lahmer, Tom ED - Werner, Frank T1 - ASSESSMENT OF INTEGRAL BRIDGES USING QUANTITATIVE MODEL EVALUATION T2 - Digital Proceedings, International Conference on the Applications of Computer Science and Mathematics in Architecture and Civil Engineering : July 04 - 06 2012, Bauhaus-University Weimar N2 - Numerical simulations in the general field of civil engineering are common for the design process of structures and/or the assessment of existing buildings. The behaviour of these structures is analytically unknown and is approximated with numerical simulation methods like the Finite Element Method (FEM). Therefore the real structure is transferred into a global model (GM, e.g. concrete bridge) with a wide range of sub models (partial models PM, e.g. material modelling, creep). These partial models are coupled together to predict the behaviour of the observed structure (GM) under different conditions. The engineer needs to decide which models are suitable for computing realistically and efficiently the physical processes determining the structural behaviour. Theoretical knowledge along with the experience from prior design processes will influence this model selection decision. It is thus often a qualitative selection of different models. The goal of this paper is to present a quantitative evaluation of the global model quality according to the simulation of a bridge subject to direct loading (dead load, traffic) and indirect loading (temperature), which induce restraint effects. The model quality can be separately investigated for each partial model and also for the coupled partial models in a global structural model. Probabilistic simulations are necessary for the evaluation of these model qualities by using Uncertainty and Sensitivity Analysis. The method is applied to the simulation of a semi-integral concrete bridge with a monolithic connection between the superstructure and the piers, and elastomeric bearings at the abutments. The results show that the evaluation of global model quality is strongly dependent on the sensitivity of the considered partial models and their related quantitative prediction quality. This method is not only a relative comparison between different models, but also a quantitative representation of model quality using probabilistic simulation methods, which can support the process of model selection for numerical simulations in research and practice. KW - Angewandte Informatik KW - Angewandte Mathematik KW - Computerunterstütztes Verfahren Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20170314-27662 UR - http://euklid.bauing.uni-weimar.de/ikm2012 SN - 1611-4086 ER - TY - THES A1 - Keitel, Holger T1 - Bewertungsmethoden für die Prognosequalität von Kriechmodellen des Betons T1 - Evaluation Methods for Prediction Quality of Concrete Creep Models N2 - Ziel dieser Arbeit ist die Entwicklung von Methoden, mit denen die Prognosequalität von Kriechmodellen des Betons bestimmt werden kann. Die Methoden werden in zwei Ausgangsszenarien unterschieden: die Bewertung ohne und die Bewertung mit Verwendung von spezifischen Versuchsdaten zum Kriechverhalten des Betons. Die Modellqualität wird anhand der Gesamtunsicherheit der prognostizierten Kriechnachgiebigkeit quantifiziert. Die Unsicherheit wird für die Kriechprognose ohne Versuchsdaten über eine Unsicherheitsanalyse unter Berücksichtigung korrelierter Eingangsparameter ermittelt. Bei der Verwendung experimenteller Daten werden die stochastischen Eigenschaften der Modellparameter mittels Bayesian Updating bestimmt. Die Bewertung erfolgt erneut basierend auf einer Unsicherheitsanalyse sowie alternativ mittels Modellselektion nach Bayes. Weiterhin wird eine auf Graphentheorie und Sensitivitätsanalysen basierende Methode zur Bewertung von gekoppelten Partialmodellen entwickelt. Damit wird der Einfluss eines Partialmodells auf das Verhalten einer globalen Tragstruktur quantifiziert, Interaktionen von Partialmodellen festgestellt und ein Maß für die Qualität eines Gesamtmodells ermittelt. N2 - The goal of this doctoral thesis is the development of methods for the evaluation of the prediction quality of concrete creep models. The methods are distinguished into two scenarios: the evaluation with and without experimental data about the creep behavior of concrete. The model quality is quantified by the total uncertainty of the predicted creep compliance. The uncertainty of the creep prognosis without using measurement data is quantified by an uncertainty analysis taking into account the parameter correlation. When experimental data is considered the stochastic properties of the creep model parameters are found by means of Bayesian Updating. The evaluation is once more based on an uncertainty analysis or, alternatively, applying Bayesian model selection. Further, an assessment method of coupled partial models based on graph theory and sensitivity analysis is developed. Therewith, the influence of classes of partial models on the global model response is quantified, interactions of partial models are detected, and a measure for the quality of the global model is derived. T3 - Schriftenreihe des DFG Graduiertenkollegs 1462 Modellqualitäten // Graduiertenkolleg Modellqualitäten - 2 KW - Kriechen KW - Bewertung KW - Prognosequalität KW - Bayes-Inferenz KW - Unsicherheitsanalyse KW - Gekoppelte Modelle KW - Coupled models KW - Bewertungsmethode KW - Evaluation methods Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20120207-15569 SN - 978-3-86068-466-5 PB - Verlag der Bauhaus-Universität Weimar CY - Weimar ER - TY - CHAP A1 - Wudtke, Idna ED - Gürlebeck, Klaus ED - Lahmer, Tom ED - Werner, Frank T1 - CONSTITUTIVE MODELING OF CRYSTALLINE MATERIALS WITH TEXTURE CHARACTERISTICS T2 - Digital Proceedings, International Conference on the Applications of Computer Science and Mathematics in Architecture and Civil Engineering : July 04 - 06 2012, Bauhaus-University Weimar N2 - The analysis of the response of complex structural systems requires the description of the material constitutive relations by means of an appropriate material model. The level of abstraction of such model may strongly affect the quality of the prognosis of the whole structure. In context to this fact, it is necessary to describe the material in a convenient sense as exact but as simple as possible. All material phenomena of crystalline materials e.g. steel, affecting the behavior of the structure, rely on physical effects which are interacting over spatial scales from subatomic to macroscopic range. Nevertheless, if the material is microscopically heterogenic, it might be appropriate to use phenomenological models for the purpose of civil engineering. Although constantly applied, these models are insufficient for steel materials with microscopic characteristics such as texture, typically occurring in hot rolled steel members or heat affected zones of welded joints. Hence, texture is manifested in crystalline materials as a regular crystallographic structure and crystallite orientation, influencing macroscopic material properties. The analysis of structural response of material with texture (e.g. rolled steel or heat affected zone of a welded joint) obliges the extension of the phenomenological material description of macroscopic scale by means of microscopic information. This paper introduces an enrichment approach for material models based on a hierarchical multiscale methodology. This has been done by describing the grain texture on a mesoscopic scale and coupling it with macroscopic constitutive relations by means of homogenization. Due to a variety of available homogenization methods, the question of an assessment of coupling quality arises. The applicability of the method and the effect of the coupling method on the reliability of the response are presented on an example. KW - Angewandte Informatik KW - Angewandte Mathematik KW - Computerunterstütztes Verfahren Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20170314-27910 UR - http://euklid.bauing.uni-weimar.de/ikm2012 SN - 1611-4086 ER - TY - JOUR A1 - Aguinaga, José Guillermo De T1 - Error in prediction due to data type availability in a coupled hydro-mechanical model JF - Electronic Journal of Geotechnical Engineering N2 - 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. KW - Sensitivitätsanalyse KW - Damm KW - Embankment, sensitivity analysis, parameter identification, Particle Swarm Optimization KW - Fehlerabschätzung Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20170413-31170 UR - https://www.scopus.com/inward/record.uri?eid=2-s2.0-84868020397&partnerID=40&md5=72c87bb112839303c1ef9a4afa8c6421 SP - 2459 EP - 2471 ER - TY - CHAP A1 - Stutz, Henning A1 - Wuttke, Frank ED - Gürlebeck, Klaus ED - Lahmer, Tom ED - Werner, Frank T1 - EVALUATION OF SOIL-STRUCTURE INTERACTION MODELS USING DIFFERENT MODEL-ROBUSTNESS APPROACHES T2 - Digital Proceedings, International Conference on the Applications of Computer Science and Mathematics in Architecture and Civil Engineering : July 04 - 06 2012, Bauhaus-University Weimar N2 - The aim of this study is to show an application of model robustness measures for soilstructure interaction (henceforth written as SSI) models. Model robustness defines a measure for the ability of a model to provide useful model answers for input parameters which typically have a wide range in geotechnical engineering. The calculation of SSI is a major problem in geotechnical engineering. Several different models exist for the estimation of SSI. These can be separated into analytical, semi-analytical and numerical methods. This paper focuses on the numerical models of SSI specific macro-element type models and more advanced finite element method models using contact description as continuum or interface elements. A brief description of the models used is given in the paper. Following this description, the applied SSI problem is introduced. The observed event is a static loaded shallow foundation with an inclined load. The different partial models to consider the SSI effects are assessed using different robustness measures during numerical application. The paper shows the investigation of the capability to use these measures for the assessment of the model quality of SSI partial models. A variance based robustness and a mathematical robustness approaches are applied. These different robustness measures are used in a framework which allows also the investigation of computational time consuming models. Finally the result shows that the concept of using robustness approaches combined with other model–quality indicators (e.g. model sensitivity or model reliability) can lead to unique model–quality assessment for SSI models. KW - Angewandte Informatik KW - Angewandte Mathematik KW - Computerunterstütztes Verfahren Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20170314-27878 UR - http://euklid.bauing.uni-weimar.de/ikm2012 SN - 1611-4086 ER - TY - CHAP A1 - De Aguinaga, José Guillermo ED - Gürlebeck, Klaus ED - Lahmer, Tom ED - Werner, Frank T1 - INFLUENCE OF DIFFERENT DATA TYPES FOR THE ESTIMATION OF HYDROMECHANICAL PARAMETERS FOR A WATER RETAINING DAM USING SYNTHETIC DATA T2 - Digital Proceedings, International Conference on the Applications of Computer Science and Mathematics in Architecture and Civil Engineering : July 04 - 06 2012, Bauhaus-University Weimar N2 - The present research analyses the error on prediction obtained under different data availability scenarios to determine which measurements contribute to an improvement of model prognosis and which not. A fully coupled 2D hydromechanical 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 ranked by scaled sensitivities, Particle Swarm Optimization is applied to determine the optimal parameter values and model validation is performed to determine the magnitude of error forecast. We compare the predictions of the optimized models with results from a forward run of the reference model to obtain actual prediction errors. The analyses presented here were performed to 31 data sets of 100 observations of varying data types. Calibrating with multiple information types instead of only one sort, brings better calibration results and improvement in model prognosis. However, when using several types of information the number of observations have to be increased to be able to cover a representative part of the model domain; otherwise a compromise between data availability and domain coverage prove best. Which type of information for calibration contributes to the best prognoses, could not be determined in advance. For the error in model prognosis does not depends on the error in calibration, but on the parameter error, which unfortunately can not be determined in reality since we do not know its real value. Excellent calibration fits with parameters’ values near the limits of reasonable physical values, provided the highest prognosis errors. While models which included excess pore pressure values for calibration provided the best prognosis, independent of the calibration fit. KW - Angewandte Informatik KW - Angewandte Mathematik KW - Computerunterstütztes Verfahren Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20170306-27607 UR - http://euklid.bauing.uni-weimar.de/ikm2012 SN - 1611-4086 ER - TY - CHAP A1 - Abbas, Tajammal A1 - Morgenthal, Guido T1 - Model combinations for assessing the flutter stability of suspension bridges T2 - Digital Proceedings, International Conference on the Applications of Computer Science and Mathematics in Architecture and Civil Engineering : July 04 - 06 2012, Bauhaus-University Weimar N2 - Long-span cable supported bridges are prone to aerodynamic instabilities caused by wind and this phenomenon is usually a major design criterion. If the wind speed exceeds the critical flutter speed of the bridge, this constitutes an Ultimate Limit State. The prediction of the flutter boundary therefore requires accurate and robust models. This paper aims at studying various combinations of models to predict the flutter phenomenon. Since flutter is a coupling of aerodynamic forcing with a structural dynamics problem, different types and classes of models can be combined to study the interaction. Here, both numerical approaches and analytical models are utilised and coupled in different ways to assess the prediction quality of the hybrid model. Models for aerodynamic forces employed are the analytical Theodorsen expressions for the motion-enduced aerodynamic forces of a flat plate and Scanlan derivatives as a Meta model. Further, Computational Fluid Dynamics (CFD) simulations using the Vortex Particle Method (VPM) were used to cover numerical models. The structural representations were dimensionally reduced to two degree of freedom section models calibrated from global models as well as a fully three-dimensional Finite Element (FE) model. A two degree of freedom system was analysed analytically as well as numerically. Generally, all models were able to predict the flutter phenomenon and relatively close agreement was found for the particular bridge. In conclusion, the model choice for a given practical analysis scenario will be discussed in the context of the analysis findings. KW - Angewandte Mathematik KW - Computerunterstütztes Verfahren KW - Angewandte Informatik Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20170306-27574 SN - 1611-4086 ER - TY - CHAP A1 - Marzban, Samira A1 - Schwarz, Jochen ED - Gürlebeck, Klaus ED - Lahmer, Tom ED - Werner, Frank T1 - MODEL QUALITY EVALUATION OF COUPLED RC FRAME-WALL SYSTEMS FOR GLOBAL DAMAGE ASSESSMENT T2 - Digital Proceedings, International Conference on the Applications of Computer Science and Mathematics in Architecture and Civil Engineering : July 04 - 06 2012, Bauhaus-University Weimar N2 - Civil engineers take advantage of models to design reliable structures. In order to fulfill the design goal with a certain amount of confidence, the utilized models should be able to predict the probable structural behavior under the expected loading schemes. Therefore, a major challenge is to find models which provide less uncertain and more robust responses. The problem gets even twofold when the model to be studied is a global model comprised of different interacting partial models. This study aims at model quality evaluation of global models with a focus on frame-wall systems as the case study. The paper, presents the results of the first step taken toward accomplishing this goal. To start the model quality evaluation of the global frame-wall system, the main element (i.e. the wall) was studied through nonlinear static and dynamic analysis using two different modeling approaches. The two selected models included the fiber section model and the Multiple-Vertical-Line-Element-Model (MVLEM). The influence of the wall aspect ratio (H=L) and the axial load on the response of the models was studied. The results from nonlinear static and dynamic analysis of both models are presented and compared. The models resulted in quite different responses in the range of low aspect ratio walls under large axial loads due to different contribution of the shear deformations to the top displacement. In the studied cases, the results implied that careful attention should be paid to the model quality evaluation of the wall models specifically when they are supposed to be coupled to other partial models such as a moment frame or a soil-footing substructure which their response is sensitive to shear deformations. In this case, even a high quality wall model would not result in a high quality coupled system since it fails to interact properly with the rest of the system. KW - Angewandte Informatik KW - Angewandte Mathematik KW - Computerunterstütztes Verfahren Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20170314-27769 UR - http://euklid.bauing.uni-weimar.de/ikm2012 SN - 1611-4086 ER -