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The development of a consistent material model for textile reinforced concrete requires the formulation and calibration of several sub-models on different resolution scales. Each of these models represents the material structure at the corresponding scale. While the models at the micro-level are able to capture the fundamental failure and damage mechanisms of the material components (e.g. filament rupture and debonding from the matrix) their computational costs limit their application to the small size representative unit cells of the material structure. On the other hand, the macro-level models provide a sufficient performance at the expense of limited range of applicability. Due to the complex structuring of the textile reinforced concrete at several levels (filament - yarn - textile - matrix) it is a non-trivial task to develop a multiscale model from scratch. It is rather more effective to develop a set of conceptually related sub-models for each structural level covering the selected phenomena of the material behavior. The homogenized effective material properties obtained at the lower level may be verified and validated using experiments and models at the higher level(s). In this paper the development of a consistent material model for textile reinforced concrete is presented. Load carrying and failure mechanisms at the micro, meso and macro scales are described and models with the focus on the specified scales are introduced. The models currently being developed in the framework of the collaborative research center are classified and evaluated with respect to the failure mechanisms being captured. The micromechanical modeling of the yarn and bonding behavior is discussed in detail and the correspondence with the experiments focused on the selected failure and interaction mechanisms is shown. The example of modeling the bond layer demonstrates the application of the presented strategy.
This paper introduces the current development of electronic catalogues of construction products. The common system architecture of Web-based electronic products catalogues are discussed, followed by a discussion on construction products information standardization and latest distributed-systems technologies for communicating construction products information. Finally, this paper presents an implementation of Web service in e-commerce systems to enable sharing of construction products information.
Trotz der langjährigen Erfahrung bei der Anwendung objektorientierter Konzepte bei der Modellierung von Gebäuden ist es bisher nicht gelungen, ein allgemein anerkanntes Gebäudemodell im Rechner abzubilden. Das mag zum einen daran liegen, daß die Standardisierung eines solchen Modells bis heute zu keinem Abschluß gekommen ist. Zum anderen aber scheint vor allem die Problematik der Abbildung eines solchen Gebäudemodells in das Objektmodell einer Programmiersprache bisher unterschätzt worden zu sein. Die erhoffte Durchgängigkeit von objektorientierter Analyse, Entwurf und Programmierung gelingt bei Anwendungen für Entwurfsaufgaben nicht. Das gilt vor allem für Anwendungen, die frühe Entwurfsphasen unterstützen und damit erst zur Definition eines Gebäudemodells beitragen. Im Bereich der Softwareentwicklung wird das Konzept des Objektes als Ordnungsbegriff zur Strukturierung von Softwaremodulen benutzt. Die Übertragung dieser Ordnung in die Welt des Ingenieurs oder Architekten zur Bezeichnung eines konkreten Elements aus einem Modell (Raum 42 aus der Menge aller Räume des Gebäudes Blumenstraße 7) kann daher nur zu begrenzten Erfolgen führen. Aus der Analyse der Widersprüchlichkeit des Objektbegriffs zwischen Softwareentwickler (Programmierer) und Softwareanwender (Ingenieur, Architekt) wird im folgenden ein Laufzeitsystem für dynamische Objektstrukturen entwickelt, das es dem Softwareentwickler erlaubt, sowohl auf die Struktur als auch auf die Ausprägung eines Modells zuzugreifen. Dem Softwareanwender können damit Werkzeuge zur Verfügung gestellt werden, die es ihm gestatten, Gebäudemodelle zu definieren. Das Laufzeitsystem enthält zum einen eine Reihe von Klassen, die es ermöglichen, die Struktur von Anwenderobjekten dynamisch zu beschreiben und zu analysieren. Eine zweite Art von Klassen erlaubt das Erzeugen und Verändern von Anwenderobjekten, die diesen Strukturen entsprechen
Building design, realization, operation and refurbishment have to take into account the environmental impacts as well as the resulting costs over a long period of time. LCA methods had to be developed for buildings because of their complexity, their long life duration and through a large number of actors who are involved. This was realized by integrating life cycle analysis, life cycle costing and building product models in integrated LCA models. However the use of such models leads to difficulties. The principal ones are the uncertainty treatment in LCA models and the lack of experience of practitioners who are not LCA specialists. Answers to these problems are the management of uncertainty and the development of simplified models for building design, construction and operation. This can be achieved with the mean of experimental plans or Monte Carlo simulation. The paper will focus on how these techniques can be used, what are their possibilities and disadvantages, particularly concerning the development of simplified models.
In recent years, the survey is performed for repair, such as a bridge and a building built in past, spending great expense. And it is anxious for the survey technique that doesn’t need cost and time more. Then, we made an idea of the technique of precise 3D model creation by 2D pictures. However, the technique of performing the improvement in accuracy of convergent photographing and automatic acquisition of corresponding points was not established. Therefore, in this research, we try to obtain a semi-automation of corresponding points acquisition from initial corresponding points and the improvement in accuracy of convergent photographing. Moreover, we applied the research to the used house of Japanese real estate, and the applicable field was selected as the high needs of the residence of 3D model. And we developed the system that everyone could create Web / 3D model house by VRML easily without requiring expensive apparatuses or expertise.
The dynamic behaviour of shells, which are widely used in construction and mechanical engineering as critical components of machinery and 3-D structures, under static and dynamic loadings is described by system of deep nonlinear differential equations. Solution of these equations can be received with assistance of technique basing on a modern numerical algorithms and computer modeling.. The system of nonlinear differential equations of vibration of the shells is proposed taking into account the inertia forces in the tangential and normal directions. Its solution is based on combination of parameter prolongation method, finite-difference method and the Newton-Kantorovich iterative algorithm that allows plotting the loading trajectories and determination of bifurcation points on them. Package of Applied Programs >SEVSOR< is a computation means to be used in research of deformation, stability and vibration in thin axically-symmetric shells of complicated shape Input data include information on shell geometry, physical and mechanical properties, bearing conditions, types of loadings and load application. Frame output of motion forms in real time or either in decelerated or accelerated time scales for creating cartoons or video films is used for analysis of the compound dynamic processes in shell-type structures.
In [1] a quaternionic reformulation of the time-harmonic Maxwell equations for chiral media was proposed and used in [2] in order to construct complete systems of quaternionic fundamental solutions convenient for numerical analysis of scattering boundary value problems. In the present contribution we give a quaternionic reformulation of time-dependent Maxwell's equations for chiral media. The Maxwell system is written as a single quaternionic equation. We obtain a fundamental solution of this equation and use it for solving Maxwell's system with sources. This is a joint work with V. V. Kravchenko. [1] Khmelnytskaya, K. V., Kravchenko, V. V. and H. Oviedo: Quaternionic integral representations for electromagnetic fields in chiral media. Telecommunications and Radio Engineering 56 (2001), # 4&5, 53-61. [2]Khmelnytskaya, K. V. , Kravchenko, V. V. and V. S. Rabinovich: Quaternionic Fundamental Solutions for Electromagnetic Scattering Problems and Application. Zeitschrift für Analysis und ihre Anwendungen 22 (2003), 147--166.
Im Rahmen eines BMWT-geförderten Projekts entstand innerhalb einer Kooperation der Ritter Energie-und Umwelttechnik mit der Universität Karlsruhe (Fachbereich Bauphysik und Technischer Ausbau) eine bedarfsgeführte Fuzzy-Regelung für eine Lüftungsanlage mit Wärmerückgewinnung. Da bei Niedrigenergie-und Passivhäusern die Wärmeverluste über die Lüftung vergleichsweise hoch sind, besteht hier noch Einsparbedarf.Eine bedarfsgeführte Regelung kann die Lüftungsrate reduzieren, wenn z.B. mehrere Bewohner abwesend sind oder Fensterlüftung betrieben wird und die Luftqualität somit gut genug ist. Ausserdem wird die Lüftung reduziert, wenn die Raumluft in der Heizperiode zu trocken wird. Die sog. Fuzzy-Logik eignet sich gut für solche Regelungsaufgaben, bei denen menschliches Empfinden und Entscheiden nachgebildet werden soll. Fuzzy bedeutet eigentlich >unscharf<, d.h. es wird mit unscharfen Begriffen gearbeitet. Eine typische Anweisung in einer Fuzzy-Regelbasis lautet z.B. >Wenn die Luft trocken ist dann wenig lüften<. Der Prozess, in dem die Zugehörigkeit einer scharfen Messgröße zu den verschiedenen Fuzzy-Sets wie >trocken<, >mittel< und >feucht< bestimmt wird, heisst >Fuzzifizierung<. Das Anwenden der Regeln und das Extrahieren des unscharfen Ergebnisses heisst >Interferenz<. Abschließend wird eine >Defuzzifizierung< vorgenommen, um wieder ein scharfes Ergebnis zu erhalten. Die Fuzzy-Lüftungsregelung hat sich in Feldtests sehr gut bewährt. Simulationsrechnungen mit dem Gebäudesimulationsprogramm >ColSim< haben ausserdem gezeigt, dass im Passivhaus bis zu 16% der für Heizen und Lüften verbrauchten Primärenergie eingespart werden kann, wenn die Fuzzy-Regelung gegen eine konventionelle Drei-Stufen-Regelung auf Stufe >Normal< antritt. Gleichzeitig wird der Wohnkomfort deutlich erhöht, da Luftqualität und Feuchte stets im richtigten Bereich bleiben.
The management of resources is an essential task in each construction company. Today, ERP systems and e-Business systems are available to assist construction companies to efficiently organise the allocation of their personnel and equipment within the company, but they cannot provide the company with the idle resources for every single task that has to be performed during a construction project. Therefore, companies should have an alternative solution to better exploit expensive resources and compensate their fixed costs, but also have them available at the right time for their own business activities. This paper outlines the approach taken by the EU funded project “e-Sharing” (IST-2001-33325) to support resource management between construction companies. It will describe requirements for the management of construction resources, its core features, and the integration approach. Therefore, we will outline the approach of an integrated resource type model supporting the management and classification of construction equipment, construction tasks and qualification profiles. The development is based on a cross-domain analysis and evaluation of existing models. ...
Some key facts about the economic environment of construction industry are explained. It is shown that construction industry is very heterogeneous and has changed drastically during the recent years due to a rapidly moving commercial environment. Two examples of todays’s use of virtual construction tools in construction projects are presented. The first example is the document control for a large international project. The second is the application of 4D modelling in the preconstruction phase of a dam project. It is shown that virtual construction, is a major international trend that currently takes up speed. Some generic industry needs for Research and Development which aims at short and medium term results are presented.