56.03 Methoden im Bauingenieurwesen
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For modeling of singular fields of stresses and deformations in elasters with a crack is offered to use of three-dimesional a special finite element. Weak compessible of elasters is taken into account on the basis of threefold approximation of fields of displacements, deformations and function of volume change. At intensive cyclic loading of the elastomer constructions with a crack it is necessary to take into account warming and large deformations at the crack top. The stress-deformed state elasters with a crack is determined from the decision of a nonlinear problem by a modified method Newton-Kantorovich. Account stress intensity factors for a rectangular plate with a various arrangement of a through crack is executed. Process of development of a surface crack and dissipative warming in prismatic a element of shift is investigated.
In this paper, we present an open-source code for the first-order and higher-order nonlocal operator method (NOM) including a detailed description of the implementation. The NOM is based on so-called support, dual-support, nonlocal operators, and an operate energy functional ensuring stability. The nonlocal operator is a generalization of the conventional differential operators. Combined with the method of weighed residuals and variational principles, NOM establishes the residual and tangent stiffness matrix of operate energy functional through some simple matrix without the need of shape functions as in other classical computational methods such as FEM. NOM only requires the definition of the energy drastically simplifying its implementation. The implementation in this paper is focused on linear elastic solids for sake of conciseness through the NOM can handle more complex nonlinear problems. The NOM can be very flexible and efficient to solve partial differential equations (PDEs), it’s also quite easy for readers to use the NOM and extend it to solve other complicated physical phenomena described by one or a set of PDEs. Finally, we present some classical benchmark problems including the classical cantilever beam and plate-with-a-hole problem, and we also make an extension of this method to solve complicated problems including phase-field fracture modeling and gradient elasticity material.
In this study, we propose a nonlocal operator method (NOM) for the dynamic analysis of (thin) Kirchhoff plates. The nonlocal Hessian operator is derived based on a second-order Taylor series expansion. The NOM does not require any shape functions and associated derivatives as ’classical’ approaches such as FEM, drastically facilitating the implementation. Furthermore, NOM is higher order continuous, which is exploited for thin plate analysis that requires C1 continuity. The nonlocal dynamic governing formulation and operator energy functional for Kirchhoff plates are derived from a variational principle. The Verlet-velocity algorithm is used for the time discretization. After confirming the accuracy of the nonlocal Hessian operator, several numerical examples are simulated by the nonlocal dynamic Kirchhoff plate formulation.
The effectiveness of working processes accomplished by various technological machines to a large extend depends on working quality of supply, transporting and orientating mechanisms which are very often produced as positional hydro-mechanical systems. The choice of their best type and regimes of work requires construction and analysis of models of their optimum steering which are complicated by nonlinearness, multy-criterialness of problem and also by occasional outbreaks of parameters and moments of steering regime changing. It was developed the common structure of such systems allowing within common scheme to vary the complexity degree of PHMS and the methods of inhibitory efforts supplement. For some systems which are complicated in series (from two-measured linear system to nine-measured non-linear) puzzles of the most fast zero-ambit getting are solved and two-criterial problems are analyzed. (T-min-speed, Z(T)- accuracy). There are suggested the computing procedures of optimum PHMS synthesis. The effectiveness of accepted methods of solving is asserted by the analogy of the results of gradually complicated models investigation and by their good analogy with the natural experiment. It was exposed the sense of heuristic methods of improving of approximately optimum steering, their elaboration on the base of theoretical models. The basic methods of optimum PGMS construction were also nominated.
Many construction and facilities management Web sites can be found on the Internet. The interested parties on construction and facilities management Web sites can find databases of best practices, calculators, analyzers, software, expert and decision support systems, neural networks, etc. Technological innovation mainly through changes in the availability of information and communication technology inclusive databases of best practices, calculators, analyzers, software, neural networks, decision support and expert systems that have been provided by a variety of new services developed by the construction and facilities management sectors. Most of all calculators, analyzers, software, decision support and expert systems, neural networks and on-line systems seek to find out how to make the most economic decisions and most of all these decisions are intended only for economic objectives. Alternatives under evaluation have to be evaluated not only from the economic position, but take into consideration qualitative, technical, technological and other characteristics as well. Based on the analysis of the existing calculators, analyzers, information, expert and decision support systems, neural networks and in order to determine most efficient versions of best practices a Decision Support Web-Based System for Construction Innovation (IDSS) was developed by Vilnius Gediminas Technical University.
Civil engineering decision support systems (construction, building life cycle, refurbishment, total quality management, innovation, etc.) created in Lithuania are described in this paper. The above decision support systems comprise of the following constituent parts: data (database and its management system), models (model base and its management system) and a user interface. Presentation of information in databases may be in conceptual (digital, textual, graphical, photographic, video) and quantitative forms. Quantitative information presented involves criteria systems and subsystems, units of measurement, values and initial weight fully defining the variants provided. The databases were developed providing a multiple criteria analysis of alternatives from economical, infrastructure, technical, technological, qualitative, legislative, social and other perspectives. This information is provided in a user-oriented way. Since the analysis of alternatives is usually performed by taking into account economical, infrastructure, technical, technological, qualitative and other factors, a model-base include models which enable a decision maker to carry out a comprehensive analysis of the variants available and make a proper choice. These systems, related questions and practical case study were analysed the paper.
This paper presents an evaluation system for steel structures of hydroelectric power stations, including hydraulic gates and penstocks, based on Fault Tree Analyasis (FTA) and performance maps. This system consists of fault tree diagrams of FTA, performance maps, design and analysis systems, and engineerin databases. These four modules are integrated by appropriate hyperlinks so that the user of this system can use it easily and seamlessly. A well developed system was applied to some illustrative example cases, and they showed that the developed methodology and system worked well and the users found the system useful and effective for their maintenance tasks at powerstations.
This paper presents a new design environment based on Multi-Agents and Virtual Reality (VR). In this research, a design system with a virtual reality function was developed. The virtual world was realized by using GL4Java, liquid crystal shutter glasses, sensor systems, etc. And the Multi-Agent CAD system with product models, which had been developed before, was integrated with the VR design system. A prototype system was developed for highway steel plate girder bridges, and was applied to a design problem. The application verified the effectiveness of the developed system.
The processes in the life cycle of buildings are characterised by highly distinct teamwork. The integration of all the distributed working participants, by providing an environment, which especially supports the communication and collaboration between the actors, is a fundamental step to improve the efficiency of the involved processes and to reduce the total costs. In this article, a link based modelling approach and its “intelligent” link management is introduced (1). This approach realises an integration environment based on a special building model that acts as a decision support system. The link-based modelling is characterised by the definition and specialisation of links between partial models. These intelligent managed links enable a very flexible and task specific data access and exchange between all the different views and partial models of the participants.
For many purposes geometric information about existing buildings is necessary, e.g. planing of conservation or reconstruction. Architectural photogrammetry is a technique to acquire 3D geometric data of buildings for a CAD model from images. In this paper the state of the art in architectural photogrammetry and some developments towards automation are described. The photogrammetric process consists of image acquisition, orientation and restitution. Special attention is put on digital methods, from digital image acquisition to restitution methods, supported by digital image processing. There are a few field of development towards automation, e.g. feature extraction, extraction of edges and lines and the detection of corresponding points. The acquired data may be used in a CAD environment or for visualization in Virtual Reality Models, using digital orthoimages for texture mapping.