TY - JOUR A1 - Êirinhevsky, V. V. A1 - Dîkhnyak, B. M. A1 - Êirichevsky, R. V. A1 - Êîzub, Y. G. T1 - Determination of the Temperature of Dissipative Warming and Parameters of Fracture in Elastomers with using of Singular Finite Elements N2 - 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. KW - Elastomer KW - Temperatur KW - Finite-Elemente-Methode Y1 - 1997 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20111215-5471 ER - TY - CHAP A1 - Zolotov, Alexander B. A1 - Akimov, Pavel T1 - Discrete-continual Finite Element Method of Analysis for Three-dimensional Curvilinear Structures N2 - This paper is devoted to discrete-continual finite element method (DCFEM) of analysis for three-dimensional curvilinear structures. Operational and variational formulations of the problem in the ring coordinate system are presented. The discrete-continual design model for structures with constant physical and geometrical parameters in longitudinal direction is offered on the basis of so-called curvilinear discrete-continual finite elements. Element coordinate system, approximation of nodal unknowns, construction of element nodal load vector are under consideration. Element system of differential equations is formulated with use of special generalized block-structured stiffness matrix of discrete-continual finite element. Local differential relations are formulated. Resultant multipoint boundary problem for system of ordinary differential equations is given. Method of analytical solution of multipoint boundary problems in structural analysis is offered as well. Its major peculiarities include universality, computer-oriented algorithm involving theory of distributions, computational stability, optimal conditionality of resultant systems, partial Jordan decomposition of matrix of coefficients, eliminating necessity of calculation of root vectors. Brief information concerning developed software is provided. KW - Raumtragwerk KW - Kreis KW - Finite-Elemente-Methode Y1 - 2003 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20111215-3848 ER - TY - CHAP A1 - van Rooyen, G.C. A1 - Olivier, A. H. T1 - Notes on structural analysis in a distributed collaboratory N2 - The worldwide growth of communication networks and associated technologies provide the basic infrastructure for new ways of executing the engineering process. Collaboration amongst team members seperated in time and location is of particular importance. Two broad themes can be recognized in research pertaining to distributed collaboration. One theme focusses on the technical and technological aspects of distributed work, while the other emphasises human aspects thereof. The case of finite element structural analysis in a distributed collaboratory is examined in this paper. An approach is taken which has its roots in human aspects of the structural analysis task. Based on experience of how structural engineers currently approach and execute this task while utilising standard software designed for use on local workstations only, criteria are stated for a software architechture that could support collaborative structural analysis. Aspects of a pilot application and the results of qualitative performance measurements are discussed. KW - Ingenieurbau KW - Verteiltes System KW - Planungsprozess KW - Modellierung KW - Finite-Elemente-Methode Y1 - 2004 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20111215-1451 ER - TY - CHAP A1 - Tzanev, D. T1 - Entwurf eines objektorientierten Modells zur Analyse von Schalentragwerken N2 - In der vorliegenden Arbeit werden dickwandige Schalentragwerke unter statischen Belastungen betrachtet. Die Schale besteht aus verschiedenen Zonen und in jeder Zone wird die Schalenmittelflaeche mittels eines eigenen Geometriegleichungssystems definiert. Das Verzerrungsfeld hat allen 6 unabhaengigen Komponenten unter der Annahme, dass die Querschnittsfasern, die normal zu der Mittelflaeche der unbelasteten Schale sind, geradelinig bleiben. Ein dreidimensionales isoparametrisches finites Element wird vorgeschlagen. Die Berechnung wird mit der Hilfe der Makroelemententechnik durchgefuehrt. In der Arbeit werden die wesentliche Parameter der Schalengeometrie, sowie auch entsprechendes Anteil von Klassen des konstruktiven Modells, definiert. Ein konstruktives Informationsmodell und ein FEM-Informationsmodell, werden entwickelt. Die Informationsverbindungen zwischen den beiden Modellen werden definiert. Diese objektorientierten Modelle werden in Programmiersprache Microsoft Visual C++ v.4.0 unter Windows 95 implementiert. Als numerisches Beispiel wird ein Bogenmauertragwerk betrachtet. KW - Bogenstaumauer KW - Schale KW - Dickwandiges Bauelement KW - Dreidimensionales Modell KW - Finite-Elemente-Methode Y1 - 1997 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20111215-4397 ER - TY - JOUR A1 - Tolok, V. A. A1 - Tolok, A. V. A1 - Gomenyuk, S. I. T1 - The instrumental System of Mechanics Problems Analysis of the deformed Solid Body N2 - In the abstract proposed is the Instrumental System of mechanics problems analysis of the deformed solid body. It supplies the researcher with the possibility to describe the input data on the object under analyses and the problem scheme based upon the variational principles within one task. The particular feature of System is possibility to describe the information concerning the object of any geometrical shape and the computation sheme according to the program defined for purpose. The Methods allow to compute the tasks with indefinite functional and indefinite geometry of the object (or the set of objects). The System provides the possibility to compute the tasks with indefinite sheme based upon the Finite Element Method (FEM). The restrictions of the System usage are therefore determined by the restrictions of the FEM itself. It contrast to other known programms using FEM (ANSYS, LS-DYNA and etc) described system possesses more universality in defining input data and choosing computational scheme. Builtin is an original Subsytem of Numerical Result Analuses. It possesses the possibility to visualise all numerical results, build the epures of the unknown variables, etc. The Subsystem is approved while solving two- and three-dimensional problems of Elasticiti and Plasticity, under the conditions of Geometrical Unlinearity. Discused are Contact Problems of Statics and Dynamics. KW - Festkörpermechanik KW - Finite-Elemente-Methode Y1 - 1997 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20111215-5361 ER - TY - CHAP A1 - Skrinar, Matjaz T1 - A simple FEM Beam Element with an Arbitrary Number of Cracks N2 - To fulfil safety requirements the changes in the static and/or dynamic behaviour of the structure must be analysed with great care. These changes are often caused by local reduction of the stiffness of the structure caused by the irregularities in the structure, as for example cracks. In simple structures such analysis can be performed directly, by solving equations of motion, but for more complex structures a different approach, usually numerical, must be applied. The problem of crack implementation into the structure behaviour has been studied by many authors who have usually modelled the crack as a massless rotational spring of suitable stiffness placed at the beam at the location where the crack occurs. Recently, the numerical procedure for the computation of the stiffness matrix for a beam element with a single transverse crack has been replaced with the element stiffness matrix written in fully symbolic form. A detailed comparison of the results obtained by using 200 2D finite elements with those obtained with a single cracked beam element has confirmed the usefulness of such element. KW - Finite-Elemente-Methode KW - Rissbildung Y1 - 1997 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20111215-4287 ER - TY - CHAP A1 - Schutte, Gerrit T1 - Zur Ermittlung von Spannungen am Rand eines elastischen Kontinuums N2 - Für den Entwurf von Ingenieurbauten ist eine zuverlässige Prognose über den Spannungsverlauf im Bauwerk und auf dessen Rand von großer Bedeutung. Eine geschlossene Lösung der elastischen Bestimmungsgleichungen des Bauwerks ist in der Regel nicht verfügbar. Es wird daher unter Verwendung der Methode der gewichteten Reste eine schwache Form der Gleichungen abgeleitet, die zu einem gemischten Arbeitsprinzip führt. Das zugehörige Finite-Elemente-Modell erlaubt es Spannungen am Rand des Bauwerks zu ermitteln, die im Gleichgewicht zu den angreifenden Lasten stehen. KW - Kontinuum KW - Elastizitätstheorie KW - Randspannung KW - Finite-Elemente-Methode Y1 - 2000 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20111215-6135 ER - TY - CHAP A1 - Schlegel, Roger A1 - Rautenstrauch, Karl T1 - Numerische Simulation von Mauerwerk als Kontinuum N2 - Im vorliegenden Beitrag wird ein in das FE-Programmsystem ANSYS implementiertes elastoplastisches Berechnungsmodell zur nichtlinearen, räumlichen Untersuchung von Mauerwerkstrukturen vorgestellt. Die Modellierung des heterogenen Baustoffs Mauerwerk erfolgt mit Hilfe eines verschmierten Ersatzkontinuums. Das anisotrope Materialverhalten wird sowohl hinsichtlich der Spannungs-Dehnungsbeziehung als auch bei der Beschreibung der Festigkeit berücksichtigt. Durch die Verwendung einer zusammengesetzten Fließbedingung ist es möglich, das Versagen der einzelnen Mauerwerkkomponenten Stein und Mörtelfugen und des Verbundes zu berücksichtigen. Dadurch ist die Anwendbarkeit des Modells für mehrere Mauerwerksarten gegeben. Die hierfür verwendeten Materialparameter sind aus einfachen Kleinkörperversuchen bestimmbar oder innerhalb gewisser Grenzen aus empirischen Formeln berechenbar. Die notwendige Beschränkung der Anzahl der Materialparameter sichert die praktische Anwendbarkeit des entwickelten Berechnungsmodells. Die numerische Umsetzung des hier verwendeten impliziten Berechnungsverfahrens lässt sich in eine lokale und eine globale Iterationsebene gliedern. Die lokale Iteration am Integrationspunkt dient der Spannungsrückführung. Dabei sind die Besonderheiten der Verarbeitung mehrflächiger Fließfiguren zu beachten. Die globale Iteration auf Systemebene sichert die Umlagerung des Residuums. Mit der Nachrechnung von Versuchsergebnissen soll das entwickelte Modell verifiziert und seine physikalische Leistungsfähigkeit eingeschätzt werden. KW - Mauerwerk KW - Modellierung KW - Elastoplastizität KW - Finite-Elemente-Methode KW - ANSYS KW - Zusammengesetzte Fließbedingung KW - Kontinuum Y1 - 2000 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20111215-6106 ER - TY - CHAP A1 - Popova, E. D. A1 - Datcheva, Maria A1 - Iankov, Roumen T1 - Mechanical Models with Interval Parameters N2 - In this paper we consider modelling of composite material with inclusions where the elastic material properties of both matrix and inclusions are uncertain and vary within prescribed bounds. Such mechanical systems, involving interval uncertainties and modelled by finite element method, can be described by parameter dependent systems of linear interval equations and process variables depending on the system solution. A newly developed hybrid interval approach for solving parametric interval linear systems is applied to the considered model and the results are compared to other interval methods. The hybrid approach provides very sharp bounds for the process variables - element strains and stresses. The sources for overestimation when dealing with interval computations are demonstrated. Based on the element strains and stresses, we introduce a definition for the values of nodal strains and stresses by using a set-theoretic approach. KW - Verbundwerkstoff KW - Modellierung KW - Finite-Elemente-Methode Y1 - 2003 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20111215-3482 ER - TY - JOUR A1 - Pick, Tobias A1 - Heimsund, Bjoern-Ove A1 - Milbradt, Peter T1 - Development and Analysis of Sparse Matrix Concepts for Finite Element Approximation on general Cells N2 - In engineering and computing, the finite element approximation is one of the most well-known computational solution techniques. It is a great tool to find solutions for mechanic, fluid mechanic and ecological problems. Whoever works with the finite element method will need to solve a large system of linear equations. There are different ways to find a solution. One way is to use a matrix decomposition technique such as LU or QR. The other possibility is to use an iterative solution algorithm like Conjugate Gradients, Gauß-Seidel, Multigrid Methods, etc. This paper will focus on iterative solvers and the needed storage techniques... KW - Finite-Elemente-Methode KW - Physikalisches Verfahren KW - Bandmatrix Y1 - 2004 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20111215-2500 ER -