@inproceedings{Wolff, author = {Wolff, Sebastian}, title = {NODALLY INTEGRATED FINITE ELEMENTS}, editor = {G{\"u}rlebeck, Klaus and K{\"o}nke, Carsten}, organization = {Bauhaus-Universit{\"a}t Weimar}, issn = {1611-4086}, doi = {10.25643/bauhaus-universitaet.2902}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170314-29028}, pages = {16}, abstract = {Nodal integration of finite elements has been investigated recently. Compared with full integration it shows better convergence when applied to incompressible media, allows easier remeshing and highly reduces the number of material evaluation points thus improving efficiency. Furthermore, understanding it may help to create new integration schemes in meshless methods as well. The new integration technique requires a nodally averaged deformation gradient. For the tetrahedral element it is possible to formulate a nodal strain which passes the patch test. On the downside, it introduces non-physical low energy modes. Most of these "spurious modes" are local deformation maps of neighbouring elements. Present stabilization schemes rely on adding a stabilizing potential to the strain energy. The stabilization is discussed within this article. Its drawbacks are easily identified within numerical experiments: Nonlinear material laws are not well represented. Plastic strains may often be underestimated. Geometrically nonlinear stabilization greatly reduces computational efficiency. The article reinterpretes nodal integration in terms of imposing a nonconforming C0-continuous strain field on the structure. By doing so, the origins of the spurious modes are discussed and two methods are presented that solve this problem. First, a geometric constraint is formulated and solved using a mixed formulation of Hu-Washizu type. This assumption leads to a consistent representation of the strain energy while eliminating spurious modes. The solution is exact, but only of theoretical interest since it produces global support. Second, an integration scheme is presented that approximates the stabilization criterion. The latter leads to a highly efficient scheme. It can even be extended to other finite element types such as hexahedrals. Numerical efficiency, convergence behaviour and stability of the new method is validated using linear tetrahedral and hexahedral elements.}, subject = {Angewandte Informatik}, language = {en} } @inproceedings{WittwerBecker, author = {Wittwer, Christof and Becker, Rainer}, title = {MODELLBASIERTE ERTRAGSKONTROLLE F{\"U}R PV ANLAGEN IN VERNETZTEN GEB{\"A}UDEN}, editor = {G{\"u}rlebeck, Klaus and K{\"o}nke, Carsten}, organization = {Bauhaus-Universit{\"a}t Weimar}, doi = {10.25643/bauhaus-universitaet.3036}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170327-30363}, pages = {5}, abstract = {Subject of the paper is the realisation of a model based efficiency control system for PV generators using a simulation model. A standard 2-diodes model of PV generator is base of the ColSim model, which is implemented in ANSI C code for flexible code exporting. The algorithm is based on discretisized U-I characteristics, which allows the calculation of string topologies witch parallel and serial PV cells and modules. Shadowing effects can be modelled down to cell configuration using polar horizon definitions. The simulation model was ported to a real time environment, to calculate the efficiency of a PV system. Embedded System technology allows the networked operation and the integration of standard I/O devices. Futher work focus on the adaption of shadowing routine, which will be adapted to get the environment conditions from the real operation.}, subject = {Architektur }, language = {de} } @inproceedings{Wittenberg, author = {Wittenberg, Reinhold}, title = {AUFBAU EINES MANAGEMENT-INFORMATIONS-SYSTEMS (M-I-S) UND BAUSTELLEN-CONTROLLINGS}, editor = {G{\"u}rlebeck, Klaus and K{\"o}nke, Carsten}, organization = {Bauhaus-Universit{\"a}t Weimar}, doi = {10.25643/bauhaus-universitaet.3035}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170327-30356}, pages = {7}, abstract = {Die meisten Insolvenzen in Deutschland kommen aus der Bauindustrie. Die Gr{\"u}nde hierf{\"u}r sind vielschichtig, jedoch kann mittels eines modern ausgerichteten M-I-S und Baustellen-Controllings fr{\"u}hzeitig erkannt werden, wie sich die Baustellenergebnisse entwickeln. Hierzu ist es notwendig, dass die Arbeitskalkulation st{\"a}ndig auf dem Laufenden gehalten wird. Nur wenn dies geschieht, sind monatliche Soll-/ Ist-Vergleiche und eine Betrachtung der cost-to-complete m{\"o}glich und sinnvoll. Eine monatlich rollierende Prognose des Baustellenergebnisses zum Bauende erm{\"o}glicht, dass gravierende Ver{\"a}nderungen des Ergebnisses umgehend aufgedeckt werden. Nur in Kenntnis dieser Entwicklungen kann das Management fr{\"u}hzeitig (im Sinne eines Fr{\"u}hwarnsystems) agieren und Steuerungsmaßnahmen ergreifen. Die Ergebnisprognose zum Bauende ist allein als Steuerungsinstrument nicht ausreichend. Die Finanzsituation der Baustelle muß auch regelm{\"a}ßig gepr{\"u}ft werden, d.h. der Leistungsstand mit der Rechnungsstellung an den Bauherren abgeglichen sowie die unbezahlten Rechnungen des Bauherren {\"u}berpr{\"u}ft werden. Das beste Prognoseergebnis ist wertlos, wenn der Bauherr seine bezogenen Leistungen nicht verg{\"u}tet. Die wirtschaftlichen Daten stehen den Verantwortlichen online im Baustellen-Informations-System (B-I-S) zur Verf{\"u}gung. Ein Ampelsystem verdeutlicht die wirtschaftliche Lage der Baustelle.}, subject = {Architektur }, language = {de} } @inproceedings{WiggenbrockSmarsly, author = {Wiggenbrock, Jens and Smarsly, Kay}, title = {A GENERIC FRAMEWORK SUPPORTING DISTRIBUTED COMPUTING IN ENGINEERING APPLICATIONS}, 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.2826}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170314-28260}, pages = {9}, abstract = {Modern distributed engineering applications are based on complex systems consisting of various subsystems that are connected through the Internet. Communication and collaboration within an entire system requires reliable and efficient data exchange between the subsystems. Middleware developed within the web evolution during the past years provides reliable and efficient data exchange for web applications, which can be adopted for solving the data exchange problems in distributed engineering applications. This paper presents a generic approach for reliable and efficient data exchange between engineering devices using existing middleware known from web applications. Different existing middleware is examined with respect to the suitability in engineering applications. In this paper, a suitable middleware is shown and a prototype implementation simulating distributed wind farm control is presented and validated using several performance measurements.}, subject = {Angewandte Informatik}, language = {en} } @inproceedings{WenderWillenbacherHuebler, author = {Wender, K. and Willenbacher, Heiko and H{\"u}bler, Reinhard}, title = {BENUTZERAD{\"A}QUATE NAVIGATIONS- UND RECHERCHETECHNOLOGIEN F{\"U}R VERTEILTE DYNAMISCHE DIGITALE BAUWERKSMODELLE}, editor = {G{\"u}rlebeck, Klaus and K{\"o}nke, Carsten}, organization = {Bauhaus-Universit{\"a}t Weimar}, doi = {10.25643/bauhaus-universitaet.3034}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170327-30349}, pages = {13}, abstract = {Hinsichtlich der Integration einzelner Bauwerkslebensphasen und der verschiedenen Beteiligten, insbesondere innerhalb von Bauplanungs- und Revitalisierungsprozessen, bestehen aktuell entscheidende Defizite. Die generelle Zielstellung der in diesem Beitrag vorgestellten Forschungsarbeiten besteht in der Unterst{\"u}tzung und Verbesserung der Integration durch die disziplin- und lebensphasen{\"u}bergreifende Bereitstellung s{\"a}mtlicher bauwerksbezogener Informationen. Dies erfordert einerseits geeignete Ans{\"a}tze zur Modellierung und Integration der vielf{\"a}ltigen disziplinspezifischen Daten, andererseits geeignete L{\"o}sungen, die einen globalen Zugriff, Navigation und Recherche im Gesamtdatenbestand erm{\"o}glichen. Die Modellierung und Verwaltung bauwerksbezogener Daten ist seit l{\"a}ngerem Gegenstand diverser Forschungsarbeiten. Im Rahmen des SFB 524 wurde ein eigener Ansatz basierend auf einem laufzeitdynamischen Partialmodellverbund entwickelt. Dieser wird in den wesentlichen Grundz{\"u}gen anderen Ans{\"a}tzen gegen{\"u}bergestellt. Den Schwerpunkt dieses Beitrags bildet jedoch die Entwicklung einer geeigneten flexiblen Navigations- und Rechercheschicht zu Realisierung projektglobaler Informationsrecherche. Aus der Sicht der Modellierung und Datenverwaltung wie auch aus der Sicht der Informationsrecherche und Informationspr{\"a}sentation in Planungsprozessen ergeben sich verschiedene Anforderungen an derartige Recherchewerkzeuge, wobei der wesentlichste Grundsatz maximale Flexibilit{\"a}t hinsichtlich verf{\"u}gbarer Darstellungstechniken und deren freie Kombination mit Techniken formaler Suchanfragen ist. Das entwickelte Systemkonzept basiert auf einem Framework, welches verschiedene Grundtypen von Recherchemodulen und deren Interaktionsprinzipien vorgibt. Einzelne Recherchemodule werden als Auspr{\"a}gungen dieser Modultypen realisiert und k{\"o}nnen je nach Bedarf laufzeitdynamisch in die Navigationsschicht integriert werden. Die technische Realisierung des Systems erfolgt im Umfeld vorhandener Prototypen aus vorangegangenen Forschungsaktivit{\"a}ten. Dieses technische Umfeld gibt verschiedene Rahmenbedingungen vor, welche im Vorfeld prototypischer Implementierungen verschiedene Adaptionen des generellen Systemkonzepts notwendig machen. Der vorliegende Beitrag stellt den aktuellen Entwicklungsstand der Systeml{\"o}sung aus konzeptioneller und technischer Sicht sowie erste prototypische Realisierungen von Recherchemodulen vor.}, subject = {Architektur }, language = {de} } @inproceedings{Weitzmann, author = {Weitzmann, R{\"u}diger}, title = {SIMPLIFIED CYCLE-BASED DESIGN OF EXTREMELY LOADED STRUCTURES}, editor = {G{\"u}rlebeck, Klaus and K{\"o}nke, Carsten}, organization = {Bauhaus-Universit{\"a}t Weimar}, doi = {10.25643/bauhaus-universitaet.3033}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170327-30338}, pages = {14}, abstract = {The design of safety-critical structures, exposed to cyclic excitations demands for non-degrading or limited-degrading behavior during extreme events. Among others, the structural behavior is mainly determined by the amount of plastic cycles, completed during the excitation. Existing simplified methods often ignore this dependency, or assume/request sufficient cyclic capacity. The paper introduces a new performance based design method that considers explicitly a predefined number of re-plastifications. Hereby approaches from the shakedown theory and signal processing methods are utilized. The paper introduces the theoretical background, explains the steps of the design procedure and demonstrates the applicability with help of an example. This project was supported by German Science Foundation (Deutsche Forschungsgemeinschaft, DFG)}, subject = {Architektur }, language = {en} } @inproceedings{WallFoersterNeumannetal., author = {Wall, Wolfgang A. and F{\"o}rster, Christiane and Neumann, Malte and Ramm, Ekkehard}, title = {ADVANCES IN FLUID-STRUCTURE INTERACTION}, editor = {G{\"u}rlebeck, Klaus and K{\"o}nke, Carsten}, organization = {Bauhaus-Universit{\"a}t Weimar}, doi = {10.25643/bauhaus-universitaet.2916}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170327-29161}, pages = {17}, abstract = {For the dynamic behavior of lightweight structures like thin shells and membranes exposed to fluid flow the interaction between the two fields is often essential. Computational fluid-structure interaction provides a tool to predict this interaction and complement or eventually replace expensive experiments. Partitioned analyses techniques enjoy great popularity for the numerical simulation of these interactions. This is due to their computational superiority over simultaneous, i.e. fully coupled monolithic approaches, as they allow the independent use of suitable discretization methods and modular analysis software. We use, for the fluid, GLS stabilized finite elements on a moving domain based on the incompressible instationary Navier-Stokes equations, where the formulation guarantees geometric conservation on the deforming domain. The structure is discretized by nonlinear, three-dimensional shell elements. Commonly used sequential staggered coupling schemes may exhibit instabilities due to the so-called artificial added mass effect. As best remedy to this problem subiterations should be invoked to guarantee kinematic and dynamic continuity across the fluid-structure interface. Since iterative coupling algorithms are computationally very costly, their convergence rate is very decisive for their usability. To ensure and accelerate the convergence of this iteration the updates of the interface position are relaxed. The time dependent, 'optimal' relaxation parameter is determined automatically without any user-input via exploiting a gradient method or applying an Aitken iteration scheme.}, subject = {Architektur }, language = {en} } @inproceedings{VuWerner, author = {Vu, Anh Tuan and Werner, Frank}, title = {OPTIMIZATION OF STEEL STRUCTURES BASED ON DIFFERENTIAL EVOLUTION ALGORITHM}, editor = {G{\"u}rlebeck, Klaus and K{\"o}nke, Carsten}, organization = {Bauhaus-Universit{\"a}t Weimar}, issn = {1611-4086}, doi = {10.25643/bauhaus-universitaet.2900}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170314-29007}, pages = {11}, abstract = {Steel structural design is an integral part of the building construction process. So far, various methods of design have been applied in practice to satisfy the design requirements. This paper attempts to acquire the Differential Evolution Algorithms in automatization of specific synthesis and rationalization of design process. The capacity of the Differential Evolution Algorithms to deal with continuous and/or discrete optimization of steel structures is also demonstrated. The goal of this study is to propose an optimal design of steel frame structures using built-up I-sections and/or a combination of standard hot-rolled profiles. All optimized steel frame structures in this paper generated optimization solutions better than the original solution designed by the manufacturer. Taking the criteria regarding the quality and efficiency of the practical design into consideration, the produced optimal design with the Differential Evolution Algorithms can completely replace conventional design because of its excellent performance.}, subject = {Angewandte Informatik}, language = {en} } @inproceedings{Vorechovsky, author = {Vorechovsk{\´y}, Miroslav}, title = {SIMULATION OF SIMPLY CROSS CORRELATED RANDOM FIELDS BY SERIES EXPANSION METHODS}, editor = {G{\"u}rlebeck, Klaus and K{\"o}nke, Carsten}, organization = {Bauhaus-Universit{\"a}t Weimar}, issn = {1611-4086}, doi = {10.25643/bauhaus-universitaet.2899}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170314-28995}, pages = {13}, abstract = {A practical framework for generating cross correlated fields with a specified marginal distribution function, an autocorrelation function and cross correlation coefficients is presented in the paper. The contribution promotes a recent journal paper [1]. The approach relies on well known series expansion methods for simulation of a Gaussian random field. The proposed method requires all cross correlated fields over the domain to share an identical autocorrelation function and the cross correlation structure between each pair of simulated fields to be simply defined by a cross correlation coefficient. Such relations result in specific properties of eigenvectors of covariance matrices of discretized field over the domain. These properties are used to decompose the eigenproblem which must normally be solved in computing the series expansion into two smaller eigenproblems. Such decomposition represents a significant reduction of computational effort. Non-Gaussian components of a multivariate random field are proposed to be simulated via memoryless transformation of underlying Gaussian random fields for which the Nataf model is employed to modify the correlation structure. In this method, the autocorrelation structure of each field is fulfilled exactly while the cross correlation is only approximated. The associated errors can be computed before performing simulations and it is shown that the errors happen especially in the cross correlation between distant points and that they are negligibly small in practical situations.}, subject = {Angewandte Informatik}, language = {en} } @inproceedings{Volkova, author = {Volkova, Viktorija}, title = {APPLICTION OF THE PHASE TRAJECTORIES MAPPING TO IDENTIFICATION}, editor = {G{\"u}rlebeck, Klaus and K{\"o}nke, Carsten}, organization = {Bauhaus-Universit{\"a}t Weimar}, doi = {10.25643/bauhaus-universitaet.3032}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170327-30329}, pages = {7}, abstract = {The reduction of oscillation amplitudes of structural elements is necessary not only for maintenance of their durability and longevity but also for elimination of a harmful effect of oscillations on people and technology operations. The dampers are widely applied for this purpose. One of the most widespread models of structural friction forces having piecewise linear relation to displacement was analysed. T The author suggests the application of phase trajectories mapping in plane "acceleration - displacement". Unlike the trajectories mapping in a plane "velocity - displacement", they don't require large number of geometrical constructions for identification of the characteristics of dynamic systems. It promotes improving the accuracy. The analytical assumptions had been verified by numerical modeling. The results show good enough coincide between numerical and analytical estimation of dissipative characteristic.}, subject = {Architektur }, language = {en} }