Dokument-ID Dokumenttyp Verfasser/Autoren Herausgeber Haupttitel Abstract Auflage Verlagsort Verlag Erscheinungsjahr Seitenzahl Schriftenreihe Titel Schriftenreihe Bandzahl ISBN Quelle der Hochschulschrift Konferenzname Quelle:Titel Quelle:Jahrgang Quelle:Heftnummer Quelle:Erste Seite Quelle:Letzte Seite URN DOI Abteilungen
OPUS4-3480 Konferenzveröffentlichung Pham, Hoang Anh; Bucher, Christian An iterative procedure for model updating based on selective sensitivity An iterative procedure for model updating based on selective sensitivity Institut für Strukturmechanik (ISM)
OPUS4-3459 Wissenschaftlicher Artikel Bucher, Christian; Frangopol, D.M. Optimization of lifetime maintenance strategies for deteriorting structures considering probabilities of violating safety, condition, and cost thresholds Optimization of lifetime maintenance strategies for deteriorting structures considering probabilities of violating safety, condition, and cost thresholds 7 Probabilistic Engineering Mechanics 1 8 Institut für Strukturmechanik (ISM)
OPUS4-3464 Konferenzveröffentlichung Brehm, Maik; Bucher, Christian Wavelet packet system identification Wavelet packet system identification Institut für Strukturmechanik (ISM)
OPUS4-3476 Konferenzveröffentlichung Most, Thomas; Bucher, Christian Adaptive response surface approach using artificial neural networks and Moving Least Squares Adaptive response surface approach using artificial neural networks and Moving Least Squares Institut für Strukturmechanik (ISM)
OPUS4-2994 Konferenzveröffentlichung Most, Thomas; Bucher, Christian; Macke, M. Gürlebeck, Klaus; Könke, Carsten A NATURAL NEIGHBOR BASED MOVING LEAST SQUARES APPROACH WITH INTERPOLATING WEIGHTING FUNCTION The Element-free Galerkin Method has become a very popular tool for the simulation of mechanical problems with moving boundaries. The internally applied Moving Least Squares approximation uses in general Gaussian or cubic weighting functions and has compact support. Due to the approximative character of this method the obtained shape functions do not fulfill the interpolation condition, which causes additional numerical effort for the imposition of the essential boundary conditions. The application of a singular weighting function, which leads to singular coefficient matrices at the nodes, can solve this problem, but requires a very careful placement of the integration points. Special procedures for the handling of such singular matrices were proposed in literature, which require additional numerical effort. In this paper a non-singular weighting function is presented, which leads to an exact fulfillment of the interpolation condition. This weighting function leads to regular values of the weights and the coefficient matrices in the whole interpolation domain even at the nodes. Furthermore this function gives much more stable results for varying size of the influence radius and for strongly distorted nodal arrangements than classical weighting function types. Nevertheless, for practical applications the results are similar as these obtained with the regularized weighting type presented by the authors in previous publications. Finally a new concept will be presented, which enables an efficient analysis of systems with strongly varying node density. In this concept the nodal influence domains are adapted depending on the nodal configuration by interpolating the influence radius for each direction from the distances to the natural neighbor nodes. This approach requires a Voronoi diagram of the domain, which is available in this study since Delaunay triangles are used as integration background cells. In the numerical examples it will be shown, that this method leads to a more uniform and reduced number of influencing nodes for systems with varying node density than the classical circular influence domains, which means that the small additional numerical effort for interpolating the influence radius leads to remarkable reduction of the total numerical cost in a linear analysis while obtaining similar results. For nonlinear calculations this advantage would be even more significant. 17 urn:nbn:de:gbv:wim2-20170327-29943 10.25643/bauhaus-universitaet.2994 Institut für Strukturmechanik (ISM)
OPUS4-2992 Konferenzveröffentlichung Most, Thomas; Bucher, Christian Gürlebeck, Klaus; Könke, Carsten ADAPTIVE RESPONSE SURFACE APPROACH USING ARTIFICIAL NEURAL NETWORKS AND MOVING LEAST SQUARES In engineering science the modeling and numerical analysis of complex systems and relations plays an important role. In order to realize such an investigation, for example a stochastic analysis, in a reasonable computational time, approximation procedure have been developed. A very famous approach is the response surface method, where the relation between input and output quantities is represented for example by global polynomials or local interpolation schemes as Moving Least Squares (MLS). In recent years artificial neural networks (ANN) have been applied as well for such purposes. Recently an adaptive response surface approach for reliability analyses was proposed, which is very efficient concerning the number of expensive limit state function evaluations. Due to the applied simplex interpolation the procedure is limited to small dimensions. In this paper this approach is extended for larger dimensions using combined ANN and MLS response surfaces for evaluating the adaptation criterion with only one set of joined limit state points. As adaptation criterion a combination by using the maximum difference in the conditional probabilities of failure and the maximum difference in the approximated radii is applied. Compared to response surfaces on directional samples or to plain directional sampling the failure probability can be estimated with a much smaller number of limit state points. 13 urn:nbn:de:gbv:wim2-20170327-29922 10.25643/bauhaus-universitaet.2992 Institut für Strukturmechanik (ISM)
OPUS4-3462 Wissenschaftlicher Artikel Most, Thomas; Bucher, Christian Stochastic simulation of cracking in concrete structures using multi-parameter random fields Stochastic simulation of cracking in concrete structures using multi-parameter random fields 19 International Journal of Reliability and Safety 168 187 Institut für Strukturmechanik (ISM)
OPUS4-3475 Konferenzveröffentlichung Most, Thomas; Bucher, Christian Application of an adaptive response surface approach for efficient structural reliability analysis Application of an adaptive response surface approach for efficient structural reliability analysis Institut für Strukturmechanik (ISM)
OPUS4-3477 Konferenzveröffentlichung Most, Thomas; Bucher, Christian An enhanced moving least squares interpolation for the element-free Galerkin method An enhanced moving least squares interpolation for the element-free Galerkin method Institut für Strukturmechanik (ISM)
OPUS4-3465 Konferenzveröffentlichung Bucher, Christian; Most, Thomas Application of approximate response functions in structural reliability analysis Application of approximate response functions in structural reliability analysis Institut für Strukturmechanik (ISM)