@inproceedings{LehnerHartmann, author = {Lehner, Karlheinz and Hartmann, Dietrich}, title = {USING INTERVAL ANALYSIS FOR STRUCTURAL ENGINEERING PROBLEMS}, editor = {G{\"u}rlebeck, Klaus and K{\"o}nke, Carsten}, organization = {Bauhaus-Universit{\"a}t Weimar}, doi = {10.25643/bauhaus-universitaet.2984}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170327-29844}, pages = {10}, abstract = {Interval analysis extends the concept of computing with real numbers to computing with real intervals. As a consequence, some interesting properties appear, such as the delivery of guaranteed results or confirmed global values. The former property is given in the sense that unknown numerical values are in known to lie in a computed interval. The latter property states that the global minimum value, for example, of a given function is also known to be contained in a interval (or a finite set of intervals). Depending upon the amount computation effort invested in the calculation, we can often find tight bounds on these enclosing intervals. The downside of interval analysis, however, is the mathematically correct, but often very pessimistic size of the interval result. This is in particularly due to the so-called dependency effect, where a single variable is used multiple times in one calculation. Applying interval analysis to structural analysis problems, the dependency has a great influence on the quality of numerical results. In this paper, a brief background of interval analysis is presented and shown how it can be applied to the solution of structural analysis problems. A discussion of possible improvements as well as an outlook to parallel computing is also given.}, subject = {Architektur }, language = {en} } @inproceedings{GalffyBaitschWellmannJelicetal., author = {Galffy, Mozes and Baitsch, Matthias and Wellmann Jelic, Andres and Hartmann, Dietrich}, title = {LIFETIME-ORIENTED OPTIMIZATION OF BRIDGE TIE RODS EXPOSED TO VORTEX-INDUCED ACROSS-WIND VIBRATIONS}, editor = {G{\"u}rlebeck, Klaus and K{\"o}nke, Carsten}, organization = {Bauhaus-Universit{\"a}t Weimar}, doi = {10.25643/bauhaus-universitaet.2956}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170327-29561}, pages = {12}, abstract = {In recent years, damages in welded connections plates of vertical tie rods of several arched steel bridges have been reported. These damages are due to fatigue caused by wind-induced vibrations. In the present study, such phenomena are examined, and the corresponding lifetime of a reference bridge in M{\"u}nster-Hiltrup, Germany, is estimated, based on the actual shape of the connection plate. Also, the results obtained are compared to the expected lifetime of a connection plate, whose geometry has been optimized separately. The structural optimization, focussing on the shape of the cut at the hanger ends, has been carried out using evolution strategies. The oscillation amplitudes have been computed by means of the Newmark-Wilson time-step method, using an appropriate load model, which has been validated by on-site experiments on the selected reference bridge. Corresponding stress-amplitudes are evaluated by multiplying the oscillation amplitudes with a stress concentration factor. This factor has been computed on the basis of a finite element model of the system "hanger-welding-connection plate", applying solid elements, according to the notch stress approach. The damage estimation takes into account the stochastics of the exciting wind process, as well as the stochastics of the material parameters (fatigue strength) given in terms of Woehler-curves. The shape optimization results in a substantial increase of the estimated hanger lifetime. The comparison of the lifetimes of the bulk plate and of the welding revealed that, in the optimized structure, the welding, being the most sensitive part in the original structure, shows much more resistance against potential damages than the bulk material.}, subject = {Architektur }, language = {en} } @inproceedings{ErlemannHartmann, author = {Erlemann, Kai and Hartmann, Dietrich}, title = {PARALLELIZATION OF A MICROSCOPIC TRAFFIC SIMULATION SYSTEM USING MPIJAVA}, editor = {G{\"u}rlebeck, Klaus and K{\"o}nke, Carsten}, organization = {Bauhaus-Universit{\"a}t Weimar}, doi = {10.25643/bauhaus-universitaet.2951}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170327-29516}, pages = {8}, abstract = {Traffic simulation is a valuable tool for the design and evaluation of road networks. Over the years, the level of detail to which urban and freeway traffic can be simulated has increased steadily, shifting from a merely qualitative macroscopic perspective to a very detailed microscopic view, where the behavior of individual vehicles is emulated realistically. With the improvement of behavioral models, however, the computational complexity has also steadily increased, as more and more aspects of real-life traffic have to be considered by the simulation environment. Despite the constant increase in computing power of modern personal computers, microscopic simulation stays computationally expensive, limiting the maximum network size than can be simulated on a single-processor computer in reasonable time. Parallelization can distribute the computing load from a single computer system to a cluster of several computing nodes. To this end, the exisiting simulation framework had to be adapted to allow for a distributed approach. As the simulation is ultimately targeted to be executed in real-time, incorporating real traffic data, only a spatial partition of the simulation was considered, meaning the road network has to be partitioned into subnets of comparable complexity, to ensure a homogenous load balancing. The partition process must also ensure, that the division between subnets does only occur in regions, where no strong interaction between the separated road segments occurs (i.e. not in the direct vicinity of junctions). In this paper, we describe a new microscopic reasoning voting strategy, and discuss in how far the increasing computational costs of these more complex behaviors lend themselves to a parallelized approach. We show the parallel architecture employed, the communication between computing units using MPIJava, and the benefits and pitfalls of adapting a single computer application to be used on a multi-node computing cluster.}, subject = {Architektur }, language = {en} } @inproceedings{BaitschHartmann, author = {Baitsch, Matthias and Hartmann, Dietrich}, title = {A FRAMEWORK FOR THE INTERACTIVE VISUALIZATION OF ENGINEERING MODELS}, editor = {G{\"u}rlebeck, Klaus and K{\"o}nke, Carsten}, organization = {Bauhaus-Universit{\"a}t Weimar}, doi = {10.25643/bauhaus-universitaet.2919}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170327-29194}, pages = {9}, abstract = {Interactive visualization based on 3D computer graphics nowadays is an indispensable part of any simulation software used in engineering. Nevertheless, the implementation of such visualization software components is often avoided in research projects because it is a challenging and potentially time consuming task. In this contribution, a novel Java framework for the interactive visualization of engineering models is introduced. It supports the task of implementing engineering visualization software by providing adequate program logic as well as high level classes for the visual representation of entities typical for engineering models. The presented framework is built on top of the open source visualization toolkit VTK. In VTK, a visualization model is established by connecting several filter objects in a so called visualization pipeline. Although designing and implementing a good pipeline layout is demanding, VTK does not support the reuse of pipeline layouts directly. Our framework tailors VTK to engineering applications on two levels. On the first level it adds new - engineering model specific - filter classes to VTK. On the second level, ready made pipeline layouts for certain aspects of engineering models are provided. For instance there is a pipeline class for one-dimensional elements like trusses and beams that is capable of showing the elements along with deformations and member forces. In order to facilitate the implementation of a graphical user interface (GUI) for each pipeline class, there exists a reusable Java Swing GUI component that allows the user to configure the appearance of the visualization model. Because of the flexible structure, the framework can be easily adapted and extended to new problem domains. Currently it is used in (i) an object-oriented p-version finite element code for design optimization, (ii) an agent based monitoring system for dam structures and (iii) the simulation of destruction processes by controlled explosives based on multibody dynamics. Application examples from all three domains illustrates that the approach presented is powerful as well as versatile.}, subject = {Architektur }, language = {en} } @inproceedings{SmarslyHartmann, author = {Smarsly, Kay and Hartmann, Dietrich}, title = {REAL-TIME MONITORING OF WIND CONVERTERS BASED ON SOFTWARE AGENTS}, editor = {G{\"u}rlebeck, Klaus and K{\"o}nke, Carsten}, organization = {Bauhaus-Universit{\"a}t Weimar}, issn = {1611-4086}, doi = {10.25643/bauhaus-universitaet.2891}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170314-28916}, pages = {11}, abstract = {Due to increasing numbers of wind energy converters, the accurate assessment of the lifespan of their structural parts and the entire converter system is becoming more and more paramount. Lifespan-oriented design, inspections and remedial maintenance are challenging because of their complex dynamic behavior. Wind energy converters are subjected to stochastic turbulent wind loading causing corresponding stochastic structural response and vibrations associated with an extreme number of stress cycles (up to 109 according to the rotation of the blades). Currently, wind energy converters are constructed for a service life of about 20 years. However, this estimation is more or less made by rule of thumb and not backed by profound scientific analyses or accurate simulations. By contrast, modern structural health monitoring systems allow an improved identification of deteriorations and, thereupon, to drastically advance the lifespan assessment of wind energy converters. In particular, monitoring systems based on artificial intelligence techniques represent a promising approach towards cost-efficient and reliable real-time monitoring. Therefore, an innovative real-time structural health monitoring concept based on software agents is introduced in this contribution. For a short time, this concept is also turned into a real-world monitoring system developed in a DFG joint research project in the authors' institute at the Ruhr-University Bochum. In this paper, primarily the agent-based development, implementation and application of the monitoring system is addressed, focusing on the real-time monitoring tasks in the deserved detail.}, subject = {Angewandte Informatik}, language = {en} } @inproceedings{SikiwatBreidtHartmann, author = {Sikiwat, Tanongsak and Breidt, Michael and Hartmann, Dietrich}, title = {COMPUTATIONAL STEERING FOR COLLAPSE SIMULATION OF LARGE SCALE COMPLEX STRUCTURES}, editor = {G{\"u}rlebeck, Klaus and K{\"o}nke, Carsten}, organization = {Bauhaus-Universit{\"a}t Weimar}, issn = {1611-4086}, doi = {10.25643/bauhaus-universitaet.2890}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170314-28908}, pages = {9}, abstract = {In order to model and simulate collapses of large scale complex structures, a user-friendly and high performance software system is essential. Because a large number of simulation experiments have to be performed, therefore, next to an appropriate simulation model and high performance computing, efficient interactive control and visualization capabilities of model parameters and simulation results are crucial. To this respect, this contribution is concerned with advancements of the software system CADCE (Computer Aided Demolition using Controlled Explosives) that is extended under particular consideration of computational steering concepts. Thereby, focus is placed on problems and solutions for the collapse simulation of real world large scale complex structures. The simulation model applied is based on a multilevel approach embedding finite element models on a local as well as a near field length scale, and multibody models on a global scale. Within the global level simulation, relevant effects of the local and the near field scale, such as fracture and failure processes of the reinforced concrete parts, are approximated by means of tailor-made multibody subsystems. These subsystems employ force elements representing nonlinear material characteristics in terms of force/displacement relationships that, in advance, are determined by finite element analysis. In particular, enhancements concerning the efficiency of the multibody model and improvements of the user interaction are presented that are crucial for the capability of the computational steering. Some scenarios of collapse simulations of real world large scale structures demonstrate the implementation of the above mentioned approaches within the computational steering.}, subject = {Angewandte Informatik}, language = {en} } @inproceedings{MiroHartmannSchanzetal., author = {Miro, Shorash and Hartmann, Dietrich and Schanz, Tom and Zarev, Veselin}, title = {SYSTEM IDENTIFICATION METHODS FOR GROUND MODELS IN MECHANIZED TUNNELING}, 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.2777}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170314-27771}, pages = {13}, abstract = {Due to the complex interactions between the ground, the driving machine, the lining tube and the built environment, the accurate assignment of in-situ system parameters for numerical simulation in mechanized tunneling is always subject to tremendous difficulties. However, the more accurate these parameters are, the more applicable the responses gained from computations will be. In particular, if the entire length of the tunnel lining is examined, then, the appropriate selection of various kinds of ground parameters is accountable for the success of a tunnel project and, more importantly, will prevent potential casualties. In this context, methods of system identification for the adaptation of numerical simulation of ground models are presented. Hereby, both deterministic and probabilistic approaches are considered for typical scenarios representing notable variations or changes in the ground model.}, subject = {Angewandte Informatik}, language = {en} } @inproceedings{LiuLeimbachHartmann, author = {Liu, Xiangqin and Leimbach, Robert and Hartmann, Dietrich}, title = {SYSTEM IDENTIFICATION OF A WIND TURBINE STRUCTURE USING ROBUST MODEL UPDATING STRATEGY}, 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.2774}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170314-27744}, pages = {11}, abstract = {This paper presents a robust model updating strategy for system identification of wind turbines. To control the updating parameters and to avoid ill-conditioning, the global sensitivity analysis using the elementary effects method is conducted. The formulation of the objective function is based on M¨uller-Slany's strategy for multi-criteria functions. As a simulationbased optimization, a simulation adapter is developed to interface the simulation software ANSYS and the locally developed optimization software MOPACK. Model updating is firstly tested on the beam model of the rotor blade. The defect between the numerical model and the reference has been markedly reduced by the process of model updating. The effect of model updating becomes more pronounced in the comparison of the measured and the numerical properties of the wind turbine model. The deviations of the frequencies of the updated model are rather small. The complete comparison including the free vibration modes by the modal assurance criteria shows the excellent coincidence of the modal parameters of the updated model with the ones from the measurements. By successful implementation of the model validation via model updating, the applicability and effectiveness of the solution concept has been demonstrated.}, subject = {Angewandte Informatik}, language = {en} } @inproceedings{WellmannJelicHartmann2003, author = {Wellmann Jelic, Andres and Hartmann, Dietrich}, title = {Einfluss von Kranfahrtlasten auf die lebensdauerorienteierte Auslegung von Rahmentragwerken}, doi = {10.25643/bauhaus-universitaet.375}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20111215-3753}, year = {2003}, abstract = {Ziel des Teilprojekts C5 des Sonderforschungsbereichs 398 an der Ruhr-Universit{\"a}t Bochum ist die Entwicklung eines lebensdauerorientierten Entwurfsmodells f{\"u}r Stahltragwerke. Das Referenzsystem der letzten F{\"o}rderperiode war eine einschiffige Stahlhalle mit Kranbahnen. Der vorliegende Beitrag stellt die Ergebnisse einer Sensitivit{\"a}tsanalyse des Stahlrahmens unter Kranfahrtlasten vor. Diese Verkehrslasten wurden, v{\"o}llig entkoppelt von weiteren {\"a}ußeren Einfl{\"u}ssen wie Wind und Schnee, als poissongetriebene Pulsprozesse beschrieben, die zuf{\"a}lligen Eigenschaften der Kranfahrtlasten wurden in den Zufallsvariablen Pulsdauer und Pulsintensit{\"a}t ber{\"u}cksichtigt. Zur Minimierung des Rechenaufwandes der Lebensdauer-untersuchung wurden a priori einige Systemparameter anhand von Parameterstudien im Hinblick auf ihre dynamische Wirkung maßgebend festgelegt. In einer darauf aufbauenden Betriebsfestigkeitsuntersuchung wurden die Sch{\"a}digungseintr{\"a}ge in einer Rahmenecke infolge von jeweils einzelnen Pulslastereignissen berechnet und in einer Datenbasis abgelegt. Eine abschließende Distance-Controlled Monte Carlo Simulation der Pulsprozesse {\"u}ber einen maximalen Zeitraum von 100 Jahren {\"u}berf{\"u}hrte die Realisationen der einzelnen Pulslasten anhand der Datenbasis in Teilsch{\"a}digungen, welche nach der Palmgren/Miner-Hypothese zu einer Gesamtsch{\"a}digung aufsummiert wurden. Der Einfluss der Kranlasten auf den Entwurf von Stahlhallen wurde durch den Vergleich der berechneten Lebensdauer und der planm{\"a}ßig vorgegebenen Nutzungsdauer quantifiziert.}, subject = {Rahmentragwerk}, language = {de} } @inproceedings{MittrupSmarslyHartmann2003, author = {Mittrup, Ingo and Smarsly, Kay and Hartmann, Dietrich}, title = {Implementierung eines webbasierten Talsperren-Monitoring-Systems}, doi = {10.25643/bauhaus-universitaet.334}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20111215-3347}, year = {2003}, abstract = {Die Bauwerks{\"u}berwachung gewinnt aus sicherheitstechnischen sowie aus wirtschaftlichen Gr{\"u}nden zunehmend an Bedeutung. Nicht nur die Bauwerkssicherheit kann durch leistungsf{\"a}hige Monitoring-Systeme angemessen beurteilt, auch die Nutzungsdauer bestehender Bauwerke kann durch die gewonnenen Informationen deutlich verl{\"a}ngert werden. Das vorliegende Papier beschreibt die Entwicklung eines webbasierten Talsperren-Monitoring-Systems, das die automatisierte Erfassung von Daten vor Ort sowie die computergest{\"u}tzte Aufbereitung und Analyse der gesammelten Messdaten erm{\"o}glicht. Das Monitoring-System ist durch seinen modularen Aufbau nicht auf die Talsperren-{\"U}berwachung beschr{\"a}nkt, sondern kann ohne großen Aufwand an andere {\"U}berwachungsaufgaben angepasst werden. Das System besteht aus drei wesentlichen Modulen: (i) einer erweiterbaren Klassenbibliothek, die die Steuerung der im Bauwerk installierten Messelektronik erm{\"o}glicht, (ii) einem webbasierten Datenerfassungsmodul, das neben der automatischen Datenerfassung eine Fernsteuerung der Messelektronik erlaubt und Funktionen zur Verwaltung der {\"U}berwachungsaufgaben bereitstellt, sowie (iii) einem webbasierten Visualisierungs- und Auswertungsmodul zur Aufbereitung und Analyse der gesammelten Daten. Alle an der {\"U}berwachung beteiligten Mitarbeiter k{\"o}nnen mit einem {\"u}blichen Web-Browser {\"u}ber das Internet auf das entwickelte System zugreifen; ein Zugriff mittels Mobiltelefon ist alternativ m{\"o}glich. Das implementierte Talsperren-Monitoring-System begleitet die beteiligten Fachleute von der Erfassung der Daten vor Ort bis hin zur Aufbereitung und Analyse der Messdaten an zentraler Stelle: Die Mitarbeiter werden durch einen einfachen Zugriff auf die installierte Messelektronik, automatisierte Messungen und umfangreiche Analysefunktionalit{\"a}ten bei ihren spezifischen Aufgaben unterst{\"u}tzt. Der bisherige manuelle Arbeitsaufwand f{\"u}r Datenerfassung, -transfer und Analyse wird somit deutlich reduziert.}, subject = {Talsperre}, language = {de} } @inproceedings{HartmannGalffyWellmannJelic2003, author = {Hartmann, Dietrich and Galffy, Mozes and Wellmann Jelic, Andres}, title = {Lebensdauerorientierter Entwurf der H{\"a}ngestangen bei Bogenbr{\"u}cken - Modellierung als Mehrebenenproblem}, doi = {10.25643/bauhaus-universitaet.304}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20111215-3046}, year = {2003}, abstract = {Der lebensdauerorientierte Entwurf von Stabbogenbr{\"u}cken, mit Zuschnitt auf die Auslegung von H{\"a}ngern, die durch Erm{\"u}dung infolge wirbelinduzierter Querschwingungen gef{\"a}hrdet sind, wird als stochastisches semi-infinites Optimierungsproblem formuliert. Zur L{\"o}sung dieses Problems sind mehrere Modellierungsebenen erforderlich, so dass ein Mehrebenenproblem entsteht. Es wird der derzeitige Entwicklungs- und Implementierungsstand bei der Umsetzung des Mehrebenenproblems in ein Entwurfsleitsystem (Software) aufgezeigt. Außerdem werden die Konzepte der noch ausstehenden Forschungsarbeit, die bereits erfolgreich beim lebensdauerorientierten Entwurf von Industriehallen mit Rahmensystem als Haupttragwerk eingesetzt wurden, diskutiert und ihre Einbildung in die bisher umgesetzte Forschungsarbeit erl{\"a}utert.}, subject = {Bogenbr{\"u}cke}, language = {de} } @inproceedings{BilekHartmann2003, author = {Bilek, Jochen and Hartmann, Dietrich}, title = {Agentenbasiertes Kooperationsmodell zur Unterst{\"u}tzung vernetzter Planungsprozesse in der Tragwerksplanung}, doi = {10.25643/bauhaus-universitaet.279}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20111215-2791}, year = {2003}, abstract = {Die heutige Situation in der Tragwerksplanung ist durch das kooperative Zusammenwirken einer gr{\"o}ßeren Anzahl von Fachleuten verschiedener Disziplinen (Architektur, Tragwerksplanung, etc.) in zeitlich befristeten Projektgemeinschaften gekennzeichnet. Bei der Abstimmung der hierdurch bedingten komplexen, dynamischen und vernetzten Planungsprozesse kommt es dabei h{\"a}ufig zu Planungsm{\"a}ngeln und Qualit{\"a}tseinbußen. Dieser Artikel zeigt auf, wie mit Hilfe der Agententechnologie L{\"o}sungsans{\"a}tze zur Verbesserung der Planungssituation erreicht werden k{\"o}nnen. Hierzu wird ein Agentenmodell f{\"u}r die vernetzt-kooperative Tragwerksplanung vorgestellt und anhand der Planung einer Fußg{\"a}ngerbogenbr{\"u}cke anschaulich demonstriert. Das Agentenmodell erfasst (1) die beteiligten Fachplaner und Organisationen, (2) die tragwerksspezifischen Planungsprozesse, (3) die zugeh{\"o}rigen (Teil-)Produktmodelle und (4) die genutzte (Ingenieur-)Software. Hieraus leiten sich die drei Teilmodelle (1) agentenbasiertes Kooperationsmodell, (2) agentenbasierte Produktmodellintegration und (3) Modell zur agentenbasierten Software-Integration ab. Der Fokus des Artikels liegt auf der Darstellung des agentenbasierten Kooperationsmodells.}, subject = {Tragwerk}, language = {de} } @article{GalffyWellmannJelicHartmann2004, author = {Galffy, Mozes and Wellmann Jelic, Andres and Hartmann, Dietrich}, title = {Lifetime-oriented modelling of vortex-induced across-wind vibrations on bridge tie rods}, doi = {10.25643/bauhaus-universitaet.253}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20111215-2536}, year = {2004}, abstract = {The influence of vortex-induces vibrations on vertical tie rods has been proved as a determinant load factor in the lifetime-oriented dimensioning of arched steel bridges. Particularly, the welded connection plates between the suspenders and the arches often exhibit cracks induced primarily rods. In this context, the synchronization of the vortex-shedding to the rod motion in a critical wind velocity range, the so-called lock-in effect, is of essential interest.}, subject = {Finite-Elemente-Methode}, language = {en} } @inproceedings{LehnerHartmann2004, author = {Lehner, Karlheinz and Hartmann, Dietrich}, title = {Scenarios for the deployment of distributed engineering applications}, doi = {10.25643/bauhaus-universitaet.147}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20111215-1476}, year = {2004}, abstract = {Although there are some good reasons to design engineering software as a stand-alone application for a single computer, there are also numerous possibilities for creating distributed engineering applications, in particular using the Internet. This paper presents some typical scenarios how engineering applications can benefit from including network capabilities. Also, some examples of Internet-based engineering applications are discussed to show how the concepts presented can be implemented.}, subject = {Ingenieurbau}, language = {en} } @inproceedings{HartmannMeissnerRueppel2004, author = {Hartmann, Dietrich and Meißner, Udo F. and Rueppel, Uwe}, title = {Integration of Productmodel Databases into Multi-Agent Systems}, doi = {10.25643/bauhaus-universitaet.141}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20111215-1410}, year = {2004}, abstract = {This paper deals with two different agent-based approaches aimed at the incorporation of complex design information into multi-agent planning systems. The first system facilitates collaborative structural design processes, the second one supports fire engineering in buildings. Both approaches are part of two different research projects that belong to the DFG1 priority program 1103 entitled "Network-based Co-operative Planning Processes in Structural Engineering" (DFG 2000). The two approaches provide similar database wrapper agents to integrate relevant design information into two multi-agent systems: Database wrapper agents make the relevant product model data usable for further agents in the multi-agent system, independent on their physical location. Thus, database wrapper agents act as an interface between multi-agent system and heterogeneous database systems. The communication between the database wrapper agents and other requesting agents presumes a common vocabulary: a specific database ontology that maps database related message contents into database objects. Hereby, the software-wrapping technology enables the various design experts to plug in existing database systems and data resources into a specific multi-agent system easily. As a consequence, dynamic changes in the design information of large collaborative engineering projects are adequately supported. The flexible architecture of the database wrapper agent concept is demonstrated by the integration of an XML and a relational database system.}, subject = {Ingenieurbau}, language = {en} } @inproceedings{BaitschHartmann2004, author = {Baitsch, Matthias and Hartmann, Dietrich}, title = {Object Oriented Finite Element Analysis for Structural Optimization using p-Elements}, doi = {10.25643/bauhaus-universitaet.108}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20111215-1089}, year = {2004}, abstract = {The optimization of continuous structures requires careful attention to discretization errors. Compared to ordinary low order formulation (h-elements) in conjunction with an adaptive mesh refinement in each optimization step, the use of high order finite elements (so called p-elements) has several advantages. However, compared to the h-method a higher order finite element analysis program poses higher demands from a software engineering point of view. In this article the basics of an object oriented higher order finite element system especially tailored to the use in structural optimization is presented. Besides the design of the system, aspects related to the employed implementation language Java are discussed.}, subject = {Konzipieren }, language = {en} } @inproceedings{WellmannJelicBaitschHartmann2004, author = {Wellmann Jelic, Andres and Baitsch, Matthias and Hartmann, Dietrich}, title = {Distributed computing of failure probabilities for structures in civil engineering}, doi = {10.25643/bauhaus-universitaet.103}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20111215-1030}, year = {2004}, abstract = {In this contribution the software design and implementation of an analysis server for the computation of failure probabilities in structural engineering is presented. The structures considered are described in terms of an equivalent Finite Element model, the stochastic properties, like e.g. the scatter of the material behavior or the incoming load, are represented using suitable random variables. Within the software framework, a Client-Server-Architecture has been implemented, employing the middleware CORBA for the communication between the distributed modules. The analysis server offers the possibility to compute failure probabilities for stochastically defined structures. Therefore, several different approximation (FORM, SORM) and simulation methods (Monte Carlo Simulation and Importance Sampling) have been implemented. This paper closes in showing several examples computed on the analysis server.}, subject = {Konzipieren }, language = {en} }