@phdthesis{Bock2010, author = {Bock, Sebastian}, title = {{\"U}ber funktionentheoretische Methoden in der r{\"a}umlichen Elastizit{\"a}tstheorie}, doi = {10.25643/bauhaus-universitaet.1417}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20100407-15030}, school = {Bauhaus-Universit{\"a}t Weimar}, year = {2010}, abstract = {Die Behandlung von geometrischen Singularit{\"a}ten bei der L{\"o}sung von Randwertaufgaben der Elastostatik stellt erh{\"o}hte Anforderungen an die mathematische Modellierung des Randwertproblems und erfordert f{\"u}r eine effiziente Auswertung speziell angepasste Berechnungsverfahren. Diese Arbeit besch{\"a}ftigt sich mit der systematischen Verallgemeinerung der Methode der komplexen Spannungsfunktionen auf den Raum, wobei der Schwerpunkt in erster Linie auf der Begr{\"u}ndung des mathematischen Verfahrens unter besonderer Ber{\"u}cksichtigung der praktischen Anwendbarkeit liegt. Den theoretischen Rahmen hierf{\"u}r bildet die Theorie quaternionenwertiger Funktionen. Dementsprechend wird die Klasse der monogenen Funktionen als Grundlage verwendet, um im ersten Teil der Arbeit ein r{\"a}umliches Analogon zum Darstellungssatz von Goursat zu beweisen und verallgemeinerte Kolosov-Muskhelishvili Formeln zu konstruieren. Im Hinblick auf die vielf{\"a}ltigen Anwendungsbereiche der Methode besch{\"a}ftigt sich der zweite Teil der Arbeit mit der lokalen und globalen Approximation von monogenen Funktionen. Hierzu werden vollst{\"a}ndige Orthogonalsysteme monogener Kugelfunktionen konstruiert, infolge dessen neuartige Darstellungen der kanonischen Reihenentwicklungen (Taylor, Fourier, Laurent) definiert werden. In Analogie zu den komplexen Potenz- und Laurentreihen auf der Grundlage der holomorphen z-Potenzen werden durch diese monogenen Orthogonalreihen alle wesentlichen Eigenschaften bez{\"u}glich der hyperkomplexen Ableitung und der monogenen Stammfunktion verallgemeinert. Anhand repr{\"a}sentativer Beispiele werden die qualitativen und numerischen Eigenschaften der entwickelten funktionentheoretischen Verfahren abschließend evaluiert. In diesem Kontext werden ferner einige weiterf{\"u}hrende Anwendungsbereiche im Rahmen der r{\"a}umlichen Funktionentheorie betrachtet, welche die speziellen Struktureigenschaften der monogenen Potenz- und Laurentreihenentwicklungen ben{\"o}tigen.}, subject = {Lineare Elastizit{\"a}tstheorie}, language = {de} } @inproceedings{HammBeissertKoenig, author = {Hamm, Matthias and Beißert, Ulrike and K{\"o}nig, Markus}, title = {SIMULATION-BASED OPTIMIZATION OF CONSTRUCTION SCHEDULES BY USING PARETO SIMULATED ANNEALING}, editor = {G{\"u}rlebeck, Klaus and K{\"o}nke, Carsten}, organization = {Bauhaus-Universit{\"a}t Weimar}, issn = {1611-4086}, doi = {10.25643/bauhaus-universitaet.2849}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170314-28499}, pages = {13}, abstract = {Within the scheduling of construction projects, different, partly conflicting objectives have to be considered. The specification of an efficient construction schedule is a challenging task, which leads to a NP-hard multi-criteria optimization problem. In the past decades, so-called metaheuristics have been developed for scheduling problems to find near-optimal solutions in reasonable time. This paper presents a Simulated Annealing concept to determine near-optimal construction schedules. Simulated Annealing is a well-known metaheuristic optimization approach for solving complex combinatorial problems. To enable dealing with several optimization objectives the Pareto optimization concept is applied. Thus, the optimization result is a set of Pareto-optimal schedules, which can be analyzed for selecting exactly one practicable and reasonable schedule. A flexible constraint-based simulation approach is used to generate possible neighboring solutions very quickly during the optimization process. The essential aspects of the developed Pareto Simulated Annealing concept are presented in detail.}, subject = {Angewandte Informatik}, language = {en} } @inproceedings{KinzlerGrabe, author = {Kinzler, Steffen and Grabe, J{\"u}rgen}, title = {APPLICATION OF MULTICRITERIAL NUMERICAL OPTIMISATION IN GEOTECHNICAL ENGINEERING}, editor = {G{\"u}rlebeck, Klaus and K{\"o}nke, Carsten}, organization = {Bauhaus-Universit{\"a}t Weimar}, issn = {1611-4086}, doi = {10.25643/bauhaus-universitaet.2861}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170314-28616}, pages = {10}, abstract = {Geotechnical constructions are sophisticated structures due to the non-linear soil behaviour and the complex soil-structure interaction, which entails great exigencies on the liable engineer during the design process. The process can be schematised as a difficult and, depending on the opportunities and skills of the processor more or less innovative, creative and heuristic search for one or a multiple of defined objectives under given boundary conditions. Wholistic approaches including numerical optimisation which support the constructing engineer in this task do not currently exist. Abstract problem formulation is not state of the art; commonly parameter studies are bounded by computational effort. Thereby potential regarding cost effectiveness, construction time, load capacity and/or serviceability are often used insufficiently. This paper describes systematic approaches for comprehensive optimisation of selected geotechnical constructions like combined pile raft foundations and quay wall structures. Several optimisation paradigms like the mono- and the multi-objective optimisation are demonstrated and their use for a more efficient design concerning various intentions is shown in example. The optimisation is implemented by using Evolutionary Algorithms. The applicability to geotechnical real world problems including nonlinearities, discontinuities and multi-modalities is shown. The routines are adapted to common problems and coupled with conventional analysis procedures as well as with numerical calculation software based on the finite element method. Numerical optimisation of geotechnical design using efficient algorithms is able to deliver highly effective solutions after investing more effort into the parameterization of the problem. Obtained results can be used for realizing different constructions near the stability limit, visualizing the sensitivity regarding the construction parameters or simply procuring more effective solutions.}, subject = {Angewandte Informatik}, language = {en} } @inproceedings{Lahmer, author = {Lahmer, Tom}, title = {HYDRO-MECHANICAL COUPLED FIELD SYSTEM IDENTIFICATION - APPLICATION TO WATER RESERVOIRS}, editor = {G{\"u}rlebeck, Klaus and K{\"o}nke, Carsten}, organization = {Bauhaus-Universit{\"a}t Weimar}, issn = {1611-4086}, doi = {10.25643/bauhaus-universitaet.2865}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170314-28650}, pages = {14}, abstract = {In this paper we present an inverse method which is capable of identifying system components in a hydro-mechanically coupled system, i.e. for fluid flow in porous media. As an example we regard water dams that were constructed more than hundred years ago but which are still in use. Over the time ageing processes have changed the condition of these dams. Within the dams fissures might have grown. The proposed method is designed to locate these fissures out of combined mechanical and hydraulic measurements. In a numerical example the fissures or damaged zones are described by a smeared crack model. The task is now to identify simultaneously the spatial distribution of Young's modulus and the hydraulic permeability due to the fact, that in regions where damages are present, the mechanical stiffness of the system is reduced and the permeability increased. The inversion is shown to be an ill-posed problem. As a consequence regularizing methods have to be applied, where the nonlinear Landweber method (a gradient type method combined with a discrepancy principle) has proven to be an efficient choice.}, subject = {Angewandte Informatik}, language = {en} }