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MODELLING THE PLASTIC HINGE IN THE STATICALLY INDETERMINABLE REINFORCED CONCRETE BAR ELEMENTS
(2006)
The paper presents the example numerical model to calculate the reinforced concrete bar structures. Usually applied methods of structure dimensioning do not include the case of plastic hinges occurrence under the limit load of construction. The model represented by A. Borcz is based on the differential equation of deflection line of the beam and it includes the effects of rearrangement of the internal forces and reological effects. The experimental parameters obtained in earlier investigations describe effects resulting from the rise of plastic hinges in the proposed equation.
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.
MODEL OF TRAM LINE OPERATION
(2006)
From passenger's perspective punctuality is one of the most important features of trams operations. Unfortunately in most cases this feature is only insufficiently fulfilled. In this paper we present a simulation model for trams operation with special focus on punctuality. The aim is to get a helpful tool for designing time-tables and for analyzing the effects by changing priorities for trams in traffic lights respectively the kind of track separation. A realization of trams operations is assumed to be a sequence of running times between successive stops and times spent by tram at the stops. In this paper the running time is modeled by the sum of its mean value and a zero-mean random variable. With the help of multiple regression we find out that the average running time is a function depending on the length of the sections and the number of intersections. The random component is modeled by a sum of two independent zero-mean random variables. One of these variables describes the disturbance caused by the process of waiting at an intersection and the other the disturbance caused by the process of driving. The time spent at a stop is assumed to be a random variable, too. Its distribution is estimated from given measurements of these stop times for different tram lines in Kraków. Finally a special case of the introduced model is considered and numerical results are presented. This paper is involved with CIVITAS-CARAVEL project: "Clean and better transport in cites". The project has received research funding from the Community's Sixth Framework Programme. The paper reflects only the author's views and the Community is not liable for any use that may be made of the information contained therein.
In diesem Beitrag wird eine mobile Software-Komponente zur Vor-Ort-Unterstützung von Bauwerksprüfungen gemäß DIN 1076 „Ingenieurbauwerke im Zuge von Strassen und Wegen, Überwachung und Prüfung“ vorgestellt, welche sich im praktischen Einsatz bei der Hochbahn AG Hamburg befindet. Mit Hilfe dieses Werkzeugs kann die Aktivität am Bauwerk in den gesamten softwaregestützten Geschäftsprozess der auwerksinstandhaltung integriert und somit die Bearbeitungszeit einer Bauwerksprüfung von der Vorbereitung bis zur Prüfbericht-Erstellung reduziert werden. Die Technologie des Mobile Computing wird unter Berücksichtigung spezieller fachlicher Randbedingungen, wie z.B. dem Einsatzort unter freiem Himmel, erläutert und es werden Methoden zur effizienten Datenerfassung mit Stift und Sprache vorgestellt und bewertet. Ferner wird die Einschränkung der Hardware durch die geringere Größe der Endgeräte, die sich durch die Bedingung der Mobilität ergibt, untersucht.
Due to economical, technical or political reasons all over the world about 100 nuclear power plants have been disconnected until today. All these power stations are still waiting for their complete dismantling which, considering one reactor, causes cost of up to one Bil. Euros and lasts up to 15 years. In our contribution we present a resource-constrained project scheduling approach minimizing the total discounted cost of dismantling a nuclear power plant. A project of dismantling a nuclear power plant can be subdivided into a number of disassembling activities. The execution of these activities requires time and scarce resources like manpower, special equipment or storage facilities for the contaminated material arising from the dismantling. Moreover, we have to regard several minimum and maximum time lags (temporal constraints) between the start times of the different activities. Finally, each disassembling activity can be processed in two alternative execution modes, which lead to different disbursements and determine the resource requirements of the considered activity. The optimization problem is to determine a start time and an execution mode for each activity, such that the discounted cost of the project is minimum, and neither the temporal constraints are violated nor the activities' resource requirements exceed the availability of any scarce resource at any point in time. In our contribution we introduce an appropriate multi-mode project scheduling model with minimum and maximum time lags as well as renewable and cumulative resources for the described optimization problem. Furthermore, we show that the considered optimization problem is NP-hard in the strong sense. For small problem instances, optimal solutions can be gained from a relaxation based enumeration approach which is incorporated into a branch and bound algorithm. In order to be able to solve large problem instances, we also propose a truncated version of the devised branch and bound algorithm.
The paper is a proposal of calculation of internal forces and dislocations in the reinforced concrete beams before and after cracking. For the ideally elastic bars transfer matrix proposed by Rakowski was applied. The effects associated with cracking were introduced by means of the Borcz's theory in the spectrally way. Numerical example was shown. The presented attitude also enables to calculate dynamic problems and those connected with the stability of the compressed and bending cracked beams and columns.
The paper contains a description of dynamic effects in the silo wall during the outflow of a stored material. The work allows for determining the danger of construction damage due to resonant vibrations and is of practical importance by determining the influence of cyclic pressures and vibro–creeping during prolonged use of a silo. The paper was devised as a result of tests on silo walls in semi-technical scale. The model is generally applicable and allows for identification of parameters in real- size silos as well.
At the 16th IKM Bock, Falcão and Gürlebeck presented examples of the application of some specially developed Maple-Software in hypercomplex analysis. Other papers of those authors continued this work and showed the efficiency of such tools for concrete numerical calculations as well as for numerical experiments, supporting the detection of new relationships and even theorems in a highly technical theoretical work. The mentioned software has been developed mainly for the use on mapping problems in the Euclidean spaces of dimension 3 and 4 by means of Bergman kernel methods (BKM), which are related to monogenic functions as solutions of generalized Cauchy-Riemann equations with respect to the Euclidean metric (Riesz system). The developed procedures concerning generalized powers of totally regular variables and the corresponding homogeneous polynomials basically rely on results and conventions introduced in the paper "Power series representation for monogenic functions in Rm+1 based on a permutational product", Complex Variables, 15, No.3, 181-191 (1990) by H. Malonek. Since 1992 H. Leutwiler, S. L. Eriksson and others developed in a number of papers a modified Clifford analysis and, particularly, a modified quaternionic analysis. The modification mainly consists in considering generalized Cauchy-Riemann equations with respect to a hyperbolic metric in a half space. The aim of this contribution is to show how through a change of the basic combinatorial relations used in the modified quaternionic analysis the aforementioned Maple-software (that has been recently published on CD-Rom as integrated part of the text book "Funktionentheorie in der Ebene und im Raum" by K. Gürlebeck, K. Habetha, and W. Sprössig, in the series "Grundstudium Mathematik" of Birkhäuser Verlag, 2006) can directly be used for numerical calculations in the modified theory.
This paper presents results of applying Fuzzy Inference System for estimation of the number of potential Park and Ride users. Usually it is difficult to evaluate the number of users because it depends on human factor and data in the considered system are uncertain. In such situation the traditional mathematical approaches can not take into consideration rough data. Therefore a fuzzy approach can be applied in this case. A fuzzy methodology is treated as a proper way to describe choice of mode of transport, and especially that uncertainty accompanied of choosing process has rather fuzzy character. The proposed approach is based on the Mamdani Fuzzy Inference System and for calculation there is used Matlab software with Fuzzy Logic Toolbox. Mamdani model requires, as an input data, knowledge of the shape of membership function. These functions can be calibrated taking into consideration results of questionnaires conducted among users of Park and Ride system. Due to lack of representative sample of users, one has decided to use results of experts' questionnaires as a input data for calibration the shape of membership functions. Describing factor will be generalized cost of the trip for different modes of transport. Proposed approach consists of two main stages: modeling of share of public/private transport trips and Multimodal model estimating number of Park and Ride users. Verification of presented methodology is treated as an indirect proof. Proposed approach can be applied for estimation of bi-modal split. Then the results are compared with traditional approaches based on logit functions. Comparable results of proposed fuzzy approach with traditional logit models can be treated as a confirmation of chosen methodology.
Die Liquiditätsplanung von Bauunternehmen XE "Liquiditätsplanung" gilt als ein wesentliches Steuerungs-, Kontroll- sowie Informationsinstrument für interne und externe Adressaten und übt eine Entscheidungsunterstützungsfunktion aus. Da die einzelnen Bauprojekte einen wesentlichen Anteil an den Gesamtkosten des Unternehmens ausmachen, besitzen diese auch einen erheblichen Einfluß auf die Liquidität und die Zahlungsfähigkeit der Bauunternehmung. Dem folgend ist es in der Baupraxis eine übliche Verfahrensweise, die Liquiditätsplanung zuerst projektbezogen zu erstellen und anschließend auf Unternehmensebene zu verdichten. Ziel der Ausführungen ist es, die Zusammenhänge von Arbeitskalkulation XE "Arbeitskalkulation" , Ergebnisrechnung XE "Ergebnisrechnung" und Finanzrechnung XE "Finanzrechnung" in Form eines deterministischen XE "Erklärungsmodells" Planungsmodells auf Projektebene darzustellen. Hierbei soll das Verständnis und die Bedeutung der Verknüpfungen zwischen dem technisch-orientierten Bauablauf und dessen Darstellung im Rechnungs- und Finanzwesen herausgestellt werden. Die Vorgänge aus der Bauabwicklung, das heißt die Abarbeitung der Bauleistungsverzeichnispositionen und deren zeitliche Darstellung in einem Bauzeitenplan sind periodisiert in Größen der Betriebsbuchhaltung (Leistung, Kosten) zu transformieren und anschließend in der Finanzrechnung (Einzahlungen., Auszahlungen) nach Kreditoren und Debitoren aufzuschlüsseln.
LIFETIME-ORIENTED OPTIMIZATION OF BRIDGE TIE RODS EXPOSED TO VORTEX-INDUCED ACROSS-WIND VIBRATIONS
(2006)
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 Münster-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.
Optimum technological solutions must take into account the entire life cycle of structures including design procedures as well as quality assurance, inspection, maintenance, and repair strategies. Unfortunately, current design standards do not provide a satisfactory basis to ensure expected structural lifetimes. The latter may vary from only a few years for temporary structures to over a century for bridges, water dams or nuclear repositories. Consistent scientific concepts are urgently required to cover this wide spectrum of lifetimes in structural design and maintenance. This was a motivation for a group of scientists at the Ruhr-University Bochum (RUB) to start a special research program supported by the German Research Foundation (DFG) within the Cooperative Research Center SFB 398 since 1996. Institutes of the University Wuppertal and of the University Essen-Duisburg joined the research group. The goal of the Center is to study sources of damage and deterioration in materials and structures, to develop consistent models and simulation methods, to predict structural lifetimes and finally to integrate this predictions into new lifetime-oriented design strategies.
Research activities in our center are organised in three Project Groups as follows:
- Modelling of lifetime effects
- Methods for lifetime-oriented structural analyses
- Future lifespan-oriented design strategies.
Die effektive Kooperation aller beteiligten Fachplaner im Bauplanungsprozess ist die Voraussetzung für wirtschaftliches und qualitativ hochwertiges Bauen. Bauprojektorganisationen bestehen in der Regel aus zahlreichen unabhängigen Planungspartnern, die örtlich verteilt spezifische Planungsaufgaben bearbeiten und die Ergebnisse in Teilproduktmodellen ablegen. Da Planungsprozesse im Bauwesen stark arbeitsteilig ablaufen, sind die Teilproduktmodelle der einzelnen Fachplanungen in hohem Maße voneinander abhängig. Ziel des hier vorgestellten Ansatzes ist die Integration der Teilproduktmodelle der Gebäudeplanung in einem netzwerkbasierten Modellverbund am Beispiel der Brandschutzplanung. Im Beitrag werden die Probleme der Verteiltheit und insbesondere der semantischen Heterogenität der involvierten Teilproduktmodelle betrachtet. Der verteilte Zugriff wird mithilfe mobiler Software-Agenten realisiert. Die Agenten können sich dabei frei im netzwerkbasierten Planungsverbund bewegen und agieren als Vertreter der Fachplaner. Das Problem der semantischen Heterogenität der Teilproduktmodelle wird auf der Basis von Ontologien gelöst. Dazu werden erstens Domänenontologien entwickelt, die Objekte der realen Welt einer abgeschlossenen Domäne, hier des Brandschutzes, abbilden. Zweitens werden Applikationsontologien entwickelt, die die einzelnen proprietären Datenhaltungen (im Sinne von Teilproduktmodellen) der jeweiligen Fachplanungen repräsentieren. Beide Ontologien werden mit einem regelbasierten Ansatz verknüpft. Im vorgestellten Anwendungsfall Brandschutz dient die Domänenontologie als einheitliche Schnittstelle für den Zugriff auf die verteilten Modelle und abstrahiert dabei von deren Datenbankspezifika und proprietären Schemata. Mithilfe von mobilen Agenten und semantischen Technologien kann so eine Plattform zur Verfügung gestellt werden, die erstens die dynamische Integration von Ressourcen in den Planungsverbund erlaubt und zweitens auf deren Basis unabhängig von der Verteiltheit und Heterogenität der eingebundenen Ressourcen ingenieurgerechte Verarbeitungsmethoden realisiert werden können.
In this study we introduce a concept of discrete Laplacian on the plane lattice and consider its iteration dynamical system. At first we discuss some basic properties on the dynamical system to be proved. Next making their computer simulations, we show that we can realize the following phenomena quite well:(1) The crystal of waters (2) The designs of carpets, embroideries (3) The time change of the numbers of families of extinct animals, and (4) The echo systems of life things. Hence we may expect that we can understand the evolutions and self organizations by use of the dynamical systems. Here we want to make a stress on the following fact: Although several well known chaotic dynamical systems can describe chaotic phenomena, they have difficulties in the descriptions of the evolutions and self organizations.
The present study was designed to investigate the underlying factors determining the visual impressions of design-patterns that have complex textures. Design-patterns produced by "the dynamical system defined by iterations of discrete Laplacians on the plane lattice" were adopted as stimuli because they were not only complex, but also defined mathematically. In the experiment, 21 graduate and undergraduate students sorted 102 design-patterns into several groups by visual impressions. Those 102 patterns were classified into 12 categories by the cluster analysis. The results showed that the regularity of pattern was a most efficient factor for determining visual impressions of design-pattern, and there were some correspondence between visual impressions and mathematical variables of design-pattern. Especially, the visual impressions were influenced greatly by the neighborhood, and less influenced by steps of iterations.
Räume und Gebäude sind heute wegen der enormen Funktionalität der technischen Gebäudeausrüstung (TGA) in Kombination mit der sonstigen Ausstattung und den diversen Anwendungsprozessen und Nutzergruppen ohne innovative Konzepte der integrierten Bedienung kaum noch beherrschbar bzw. optimal nutzbar. Dies gilt sowohl für Wohn- als auch für Zweckimmobilien. Die Gebäudeleittechnik (GLT) und die Gebäudeautomation (GA) können hier unter sinnvoller Integration der Möglichkeiten der Mikroelektronik, Multimedia-, Kommunikations- und Informationstechnik erheblich zu nutzbringenden Innovationen beitragen. Die Automobilindustrie hat in den letzten Jahren gezeigt, wie durch einen integralen Systemansatz und durch Einsatz von Elektronik, Kommunikations- und Informationstechnik eine sinnvolle technische Assistenz der Anwender machbar ist. Genannt sei hier das Konzept des Cockpits mit integrierter Funktionsbündelung und der Informationskonzentration am Armaturenbrett. Im Gegensatz zum Automobil ist der Bereich der technischen Gebäudeausstattung in Wohn- und Nutzimmobilien gekennzeichnet durch eine starke Fragmentierung in unterschiedlichste Gewerke unter Beteiligung vieler oft schlecht koordinierter Akteure. Durch das Duisburger inHaus-Innovationszentrum für Intelligente Raum- und Gebäudesysteme der Fraunhofer-Gesellschaft wurden in den letzten Jahren neuartige Konzepte der Systemintegration heterogener Technik auf der Basis von Middleware-Plattformen und Multimedia-Technologien und -Geräten entwickelt, getestet und in die Anwendung getragen. Einer der ersten Systemanwendungen dieses offenen Infrastrukturkonzepts ist die integrierte Systembedienung mit zum Teil völlig neuen Bedienkonzepten und einer starken Bedienungsvereinfachung auch komplexester Technikausrüstungen in Immobilien. Der Beitrag beschreibt nach einer Analyse der Ausgangslage die technologischen Grundzüge der integrierten Systembedienung. Es folgen einige Anwendungsbeispiele und eine zusammenfassende Bewertung mit einem Ausblick auf weiterführende Aktivitäten.
A concept for integrated modeling of urban and rural hydrology is introduced. The concept allows for simulations on the catchment scale as well as on the local scale. It is based on a 2-layer-approach which facilitates the parallel coupling of a catchment hydrology model with an urban hydrology model, considering the interactions between the two systems. The concept has been implemented in a computer model combining a grid based distributed hydrological catchment model and a hydrological urban stormwater model based on elementary units. The combined model provides a flexible solution for time and spatial scale integration and offers to calculate separate water balances for urban and rural hydrology. Furthermore, it is GIS-based which allows for easy and accurate geo-referencing of urban overflow structures, which are considered as points of interactions between the two hydrologic systems. Due to the two-layer-approach, programs of measures can be incorporated in each system separately. The capabilities of the combined model have been tested on a hypothetical test case and a real world application. It could be shown that the model is capable of accurately quantifying the effects of urbanization in a catchment. The affects of urbanization can be analyzed at the catchment outlet, but can also be traced back to its origins, due to the geo-referencing of urban overflow structures. This is a mayor advantage over conventional hydrological catchment models for the analysis of land use changes.
Water resources development and management is a complex problem. It includes the design and operation of single system components, often as part of larger interrelated systems and usually on the basis of river basins. While several decades ago the dominant objective was the maximization of economic benefit, other objectives have evolved as part of the sustainable development envisaged. Today, planning and operation of larger water resources systems is practically impossible without adequate computer tools, normally being one or several models, increasingly combined with data bank management systems and multi criteria assessment procedures in decision support systems. The use of models in civil engineering already has a long history when structural engineering is considered. These design support models, however, must rather be seen as expert systems made to support the engineer with his daily work. They often have no direct link to stakeholders and the decision makers community. The scale of investigation is often much larger in water resources engineering than in structural engineering which is related to different stakeholders and decision making procedures. Still, several similarities are obvious which can be summarized as the search for a compromise solution on a complex, i.e. multiobjective and interdisciplinary decision problem. While in structural engineering e.g. aestetics, stability and energy consumption might be important evaluation criteria in addition to construction and maintenance cost other or additional criteria have to be considered in water resources planning such as political, environmental and social criteria. In this respect civil engineers tend to overemphasize technical criteria. For the future the existing expert systems should be embedded into an improved decision support shell, keeping in mind that decision makers are hardly interested in numerical modelling results. The paper will introduce into the problem and demonstrate the state of the art by means of an example.
HYPERMONOGENIC POLYNOMIALS
(2006)
It is well know that the power function is not monogenic. There are basically two ways to include the power function into the set of solutions: The hypermonogenic functions or holomorphic Cliffordian functions. L. Pernas has found out the dimension of the space of homogenous holomorphic Cliffordian polynomials of degree m, but his approach did not include a basis. It is known that the hypermonogenic functions are included in the space of holomorphic Cliffordian functions. As our main result we show that we can construct a basis for the right module of homogeneous holomorphic Cliffordian polynomials of degree m using hypermonogenic polynomials and their derivatives. To that end we first recall the function spaces of monogenic, hypermonogenic and holomorphic Cliffordian functions and give the results needed in the proof of our main theorem. We list some basic polynomials and their properties for the various function spaces. In particular, we consider recursive formulas, rules of differentiation and properties of linear independency for the polynomials.
Solid behavior as well as liquid behavior characterizes the flow of granular material in silos. The presented model is based on an appropriate interaction of a displacement field and a velocity field. The constitutive equations and the applied algorithm are developed from the exact solution for a standard case. The standard case evolves from a very tall vertical plane strain silo containing material that flows at a constant speed. No horizontal displacements and velocities take place. No changes regarding the field values arise in the vertical direction and in time. Tension is not allowed at any point. Coulomb friction represents the effects of the vertical walls. The interaction between the flowing material and the walls is covered by a forced boundary condition resulting in an additional matrix for the solid component as well as for the liquid component. The resulting integral equations are designed to be solved directly. Three coefficients describe the properties of the granular material. They govern elastic solid behavior in combination with viscous liquid behavior.