Teses / dissertações sobre o tema "Problème de torsion"
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Zoubairi, Hakima. "Homogénéisation et contrôle optimal pour des problèmes de Stokes et pour un problème de torsion élastique". Metz, 2001. http://tel.ccsd.cnrs.fr/documents/archives0/00/00/12/90/index_fr.html.
Texto completo da fonteThis thesis is devoted to the study of optimal control and homogeneization for some problems associated to the Stokes equation and also for an elastic torsion problem. For each of the problems, a control act on the state equation. This control belongs to a set of admissible controls. We consider a cost function wich depends on the state and on the control. The control optimal (unique) is the function in the set of admissible controls which minimizes the cost function. Then we study its behaviour. If it admits a limit, we characterize it as an optimal control associated to the homogenized problem. In the first part, we study an optimal control problem in a mixture of two fluids. Those fluids are distributed periodically in a bi or three-dimensionnal domain. Each fluid obeys the Stokes equations. In the second part, we study also a mixture of two fluids but separated by an rapidly oscillating interface. These fluids obeys the Stoke equations. In the third part, we study an optimal control problem for the Stokes equations in perforated domains. We suppose that the size of the perforations is smaller than a given period. In the last part, we study the optimal control of an elastic torsion problem. For each of these parts, we characterize the limit of the optimal control as the optimal control of the limit problem
ZOUBAIRI, Hakima. "Homogénéisation et Controle Optimal pour des Problèmes de Stokes et pour un Problème de Torsion Elastique". Phd thesis, Université de Metz, 2001. http://tel.archives-ouvertes.fr/tel-00001290.
Texto completo da fonteAit, El Amrani Asmâa. "Homogénéisation d'un problème de torsion élastique pour un arbre cylindrique de section multiconnexe et multiperiodique". Vandoeuvre-les-Nancy, INPL, 2000. http://www.theses.fr/2000INPL074N.
Texto completo da fonteHammedi, Hiba. "Analyse spectrale des guides d'ondes "twistés"". Thesis, Toulon, 2016. http://www.theses.fr/2016TOUL0001/document.
Texto completo da fonteIn this thesis we study the spectral properties of perturbed 3D quantum waveguides (tubes). We mainly consider two types of perturbation:The first type is a geometric perturbation. More precisely, we study the Laplace operator with Dirichlet boundary conditions defined in a twisted tube. The twist that we consider is a constant one that has been locally perturbed by a function of same sign (a repulsive twist). The second type of perturbation is done by changing locally the boundary conditions. In fact, we study the Laplacian operator with Dirichlet conditions everywhere on the boundary of the tube except on a bounded part where we consider the Neumann conditions. In one hand we study the straight tubes (with no geometric perturbations) to figure out the effect of perturbation that occurred in the boundary conditions. In the other hand we study the twisted tubes to establish a comparison between the opposite effects of these two types of perturbation (the geometric one and the change that we imposed on the boundary conditions)
Générau, François. "Sur une approximation variationnelle stable du cut locus, et un problème isopérimetrique non local". Thesis, Université Grenoble Alpes, 2020. http://www.theses.fr/2020GRALM014.
Texto completo da fonteThis thesis is composed of two parts. In the first part, we study a generalization of the variational problem of elastic-plastic torsion problem to manifolds. We show that in the case of manifolds, the problem is not equivalent to an obstacle type problem, contrary to the euclidean case, but we establish the equivalence when the parameter of the problem goes to infinity. We show, as in the euclidean case, that the non contact set contains the cut locus of the manifold, and converges to the latter in the Hausdorff sense. What is more, we show that the minimizers of the problem are uniformly semiconcave. We deduce a stable approximation of the cut locus, in the spirit of the lambda medial axis of Chazal and Lieutier. We then use this result to compute numerically the cut locus of some surfaces of varied geometries.In the second part, we study an extension of a nonlocal isoperimetric problem. More precisely, we add a confinement potential to Gamow's liquid drop model for the nucleus. We then study large volume minimizers. We show that for certain sets of parameters, large volume minimizers converge to the ball, or may even exactly be the ball. Moreover, we develop a numerical method for this variational problem. Our results confirm numerically a conjecture of Choksi and Peletier, in dimension 2: it seems that minimizers of Gamow'sliquid drop model are balls as long as they exist
Perin, Chloé. "Plongements élémentaires dans un groupe hyperbolique sans torsion". Phd thesis, Université de Caen, 2008. http://tel.archives-ouvertes.fr/tel-00460330.
Texto completo da fonteGraff, Emmanuel. ""Link-homotopy" in low dimensional topology". Electronic Thesis or Diss., Normandie, 2023. http://www.theses.fr/2023NORMC244.
Texto completo da fonteThis thesis explores low-dimensional topology, with a focus on knot theory. Knot theory is dedicated to the study of knots as commonly understood: a piece of string tied in space or, more generally, links formed by taking several pieces of string. Knots and links are studied up to deformation, for example, up to isotopy, which involves manipulations that do not require cutting or passing the string through itself. This thesis explores link-homotopy, a more flexible equivalence relation where distinct components remain disjoint, but a single component can self-intersect. The theory of claspers, powerful tools of surgery, is developed up to link-homotopy. Their use allows for a geometric proof of the classification of links with 4 components or less up to link-homotopy. Special attention is then given to braids, mathematical objects related to knots and links. It is shown that the homotopy braid group is linear, meaning it is faithfully represented by a subgroup of matrices. New group presentations are also proposed. Finally, it is established that the homotopy braid group is torsion-free for any number of components. This last result draws upon the broader context of welded knot theory
Finski, Siarhei. "On some problems of holomorphic analytic torsion". Thesis, Sorbonne Paris Cité, 2019. https://theses.md.univ-paris-diderot.fr/FINSKI_Siarhei_va.pdf.
Texto completo da fonteIn the first context, we study the asymptotics of the analytic torsion, when a Hermitian holomorphic vector bundle is twisted by an increasing power of a positive line bundle. In the second context, we generalize the theory of analytic torsion for surfaces with hyperbolic cusps. Motivated by singularities appearing in complete metrics of constant scalar curvature -1 on stable Riemann surfaces, we suppose that the metric on the surface is smooth outside a finite number points in the neighborhood of which it can to have singularities like Poincaré metric has on a punctured disc. We fix a Hermitian holomorphic vector bundle which has at worst logarithmic singularities in the neighborhood of the marked points. For these data, by renormalizing the trace of the heat operator, we construct the analytic torsion and study its properties. Then we study the properties of the analytic torsion in family setting: we prove the curvature theorem, we study the behavior of the analytic torsion when the cusps are created by degeneration and we give some applications to the moduli spaces of pointed curves
Bury, A. S. "Torsional vibration problems in reciprocating machinery". Thesis, Сумський державний університет, 2014. http://essuir.sumdu.edu.ua/handle/123456789/34851.
Texto completo da fonteZoubairi, Hakima Alabau Fatiha. "Homogénéisation et contrôle optimal pour des problèmes de stokes et pour un problème de torsion élastique". [S.l.] : [s.n.], 2001. http://tel.ccsd.cnrs.fr/documents/archives0/00/00/12/90/index_fr.html.
Texto completo da fonteZine, Abidine Ouazzani Ali. "Prise en compte de cavites dans des problemes aux limites elliptiques : application a la torsion elastique". Paris 6, 1986. http://www.theses.fr/1986PA066584.
Texto completo da fonteMartinez, Metzmeier César. "Two problems in arithmetic geometry. Explicit Manin-Mumford, and arithmetic Bernstein-Kusnirenko". Thesis, Normandie, 2017. http://www.theses.fr/2017NORMC224/document.
Texto completo da fonteIn the first part of this thesis we present sharp bounds on the number of maximal torsion cosets in a subvariety of a complex algebraic torus $(\mathbb{C}^{\times})^n$ and of an Abelian variety. In both cases, we give an explicit bound in terms of the degree of the defining polynomials and the ambient variety. Moreover, the dependence on the degree of the polynomials is sharp. In the case of the complex torus, we also give an effective bound in terms of the toric degree of the subvariety. As a consequence of the latter result, we prove the conjectures of Ruppert, and Aliev and Smyth on the number of isolated torsion points of a hypersurface. These conjectures bound this number in terms of the multidegree and the volume of the Newton polytope of a polynomial defining the hypersurface, respectively.In the second part of the thesis, we present an upper bound for the height of isolated zeros, in the torus, of a system of Laurent polynomials over an adelic field satisfying the product formula. This upper bound is expressed in terms of the mixed integrals of the local roof functions associated to the chosen height function and to the system of Laurent polynomials. We also show that this bound is close to optimal in some families of examples. This result is an arithmetic analogue of the classical Bern\v{s}tein-Ku\v{s}nirenko theorem
Heffernan, Rhys. "Addressing One-Dimensional Protein Structure Prediction Problems with Machine Learning Techniques". Thesis, Griffith University, 2018. http://hdl.handle.net/10072/381401.
Texto completo da fonteThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Eng & Built Env
Science, Environment, Engineering and Technology
Full Text
Kleiss, Torsten [Verfasser], e Hans Wilhelm [Akademischer Betreuer] Alfen. "Institutional Arrangements for Municipal Solid Waste Combustion Projects / Torsten Kleiss ; Betreuer: Hans Wilhelm Alfen". Weimar : Professur Betriebswirtschaftslehre im Bauwesen, 2008. http://d-nb.info/1116609460/34.
Texto completo da fonteCzekajski, Casimir. "Application de la méthode des équations intégrales sur la frontière à certains types de problèmes rencontrés en mécanique des structures". Toulouse, ENSAE, 1985. http://www.theses.fr/1985ESAE0008.
Texto completo da fonteSpeer, Arne Verfasser], Tanja [Akademischer Betreuer] [Kessel e Torsten [Akademischer Betreuer] Böger. "Entwicklung von Key Performance Indikatoren auf dem Weg vom Erhaltungsmanagement zum Asset Management für Bundesautobahnen / Arne Speer ; Tanja Kessel, Torsten Böger". Braunschweig : Technische Universität Braunschweig, 2019. http://d-nb.info/1181946158/34.
Texto completo da fonteSpeer, Arne [Verfasser], Tanja [Akademischer Betreuer] Kessel e Torsten [Akademischer Betreuer] Böger. "Entwicklung von Key Performance Indikatoren auf dem Weg vom Erhaltungsmanagement zum Asset Management für Bundesautobahnen / Arne Speer ; Tanja Kessel, Torsten Böger". Braunschweig : Technische Universität Braunschweig, 2019. http://d-nb.info/1181946158/34.
Texto completo da fonteTomanek, Dagmar P. [Verfasser], e Torsten [Akademischer Betreuer] Eymann. "Möglichkeiten und Grenzen der Wertschöpfungsoptimierung von medizinischen Dienstleistungen mithilfe der Wertstromorientierung am Beispiel von klinischen Prozessen. / Dagmar P. Tomanek ; Betreuer: Torsten Eymann". Bayreuth : Universität Bayreuth, 2018. http://d-nb.info/1159632898/34.
Texto completo da fonteKushnarov, Andriy. "Numerical Method For Conform Reflection". Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/2/12611426/index.pdf.
Texto completo da fonteZiebertz, Torsten [Verfasser], Christine [Akademischer Betreuer] Schwarzer e Eckard [Akademischer Betreuer] König. "Theoretische Annahmen personzentrierter Beraterinnen und Berater, die mit Familien arbeiten : eine qualitative Studie / Torsten Ziebertz. Gutachter: Christine Schwarzer ; Eckard König". Düsseldorf : Universitäts- und Landesbibliothek der Heinrich-Heine-Universität Düsseldorf, 2011. http://d-nb.info/1015363261/34.
Texto completo da fonteSilva, Henrique Furia. "Formulação do problema da torção uniforme em barras de seção transversal maciça". Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/3/3144/tde-20022006-150915/.
Texto completo da fonteThe main purpose of this essay is to present the issue of the uniform torsion in solid section bars and to solve it analytically to achieve the moment of inertia to the torsion of the transversal section and the displacements throughout the whole bar. This essay was developed in the Elasticity Theory context, using the semi-inverse method to determine the Saint-Venant equations to the uniform torsion. The sections in ellipse and equilateral triangle were solved using the Prandtl stress function, the warping function and its harmonic conjugate. The rectangular section was solved using the warping and the Prandtl functions developed in infinite series. A formulation based on matrixes was developed using the Galerkin method to solve problems that do not have closed solution.
Alles, Torsten [Verfasser]. "Anforderungsorientierte Rehabilitation zur Förderung der Teilhabe am Arbeitsleben durch Einsatz von Assessment : eine kontrollierte Interventionsstudie im Rahmen der stationären Rehabilitation von Rückenleiden / Torsten Alles". Köln : Zentralbibliothek der Deutschen Sporthochschule, 2007. http://d-nb.info/1103050230/34.
Texto completo da fonteYamamoto, Taira. "Nonlinear finite element analysis of transverse shear and torsional problems in reinforced concrete shells". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0002/MQ45940.pdf.
Texto completo da fonteRioux, Myriam. "Numerical Computations of Action Potentials for the Heart-torso Coupling Problem". Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/20533.
Texto completo da fonteDiesel, Torsten [Verfasser], Marin [Akademischer Betreuer] Trenk, Marin [Gutachter] Trenk e Iris [Gutachter] Gareis. ""7 people and a mayor": westernized communities, social change and violence among the Inuit of Nunavut : volumes 1 and 2 / Torsten Diesel ; Gutachter: Marin Trenk, Iris Gareis ; Betreuer: Marin Trenk". Frankfurt am Main : Universitätsbibliothek Johann Christian Senckenberg, 2019. http://d-nb.info/1195601581/34.
Texto completo da fonteKrüger, Torsten [Verfasser]. "Die Auswirkungen des Waldsterbens und der Einfluß weiterer Faktoren auf die Populationsschwankungen des Birkhuhnes (Tetrao tetrix L.) im sächsischen Erzgebirge auf Grundlage einer Luftbildanalyse / Torsten Krüger". Aachen : Shaker, 2004. http://d-nb.info/1170531407/34.
Texto completo da fontePollok, Patrick [Verfasser], Frank Thomas [Akademischer Betreuer] Piller e Torsten Oliver [Akademischer Betreuer] Salge. "Three Essays on Crowdsourcing for Technical Problem Solving / Patrick Pollok ; Frank Thomas Piller, Torsten Oliver Salge". Aachen : Universitätsbibliothek der RWTH Aachen, 2017. http://d-nb.info/116794478X/34.
Texto completo da fonteBohonak, Noni McCullough. "Finding a Fitness Function to be Used with Genetic Algorithms to Solve a Protein Folding Problem: The ab initio Prediction of a Protein Using Torsion Angles". NSUWorks, 2000. http://nsuworks.nova.edu/gscis_etd/418.
Texto completo da fontePešek, Ondřej. "Stabilitní problémy prutů z vrstveného konstrukčního skla". Doctoral thesis, Vysoké učení technické v Brně. Fakulta stavební, 2018. http://www.nusl.cz/ntk/nusl-390277.
Texto completo da fonteValeš, Jan. "Citlivostní analýza stabilitních problémů ocelových konstrukcí". Doctoral thesis, Vysoké učení technické v Brně. Fakulta stavební, 2018. http://www.nusl.cz/ntk/nusl-390286.
Texto completo da fonteHecher, Markus [Verfasser], Stefan [Akademischer Betreuer] Woltran, Torsten [Akademischer Betreuer] Schaub, Mirosław [Gutachter] Truszczynski e Heribert [Gutachter] Vollmer. "Advanced tools and methods for treewidth-based problem solving / Markus Hecher ; Gutachter: Mirosław Truszczynski, Heribert Vollmer ; Stefan Woltran, Torsten Schaub". Potsdam : Universität Potsdam, 2021. http://d-nb.info/1238686745/34.
Texto completo da fonteBEZZICCHERI, MATTEO. "Problems in measurement of mechanical loads in wind turbines: bending/torsional moments by strain gage bridges and torque by optical transducer". Doctoral thesis, Università Politecnica delle Marche, 2018. http://hdl.handle.net/11566/252847.
Texto completo da fonteThis thesis discusses the complexity of measuring mechanical loads on large wind turbines; parameters that play a crucial role in the certification and monitoring of wind turbines. The most important mechanical loads on a wind turbine are bending and torsional moments that are usually measured through full strain gage bridges, as recommended by the standard IEC 61400-13. This thesis discusses the guidelines to design the strain gage measurement chain and a comparison among the different calibration procedures: analytical, external loads and gravity. This work proposes static-dynamic models for a gravity calibration, comments on the attainable range of calibration and presents an uncertainty analysis of the calibration process. Even if measurement should take place in isothermal condition, this is not always the case in real world practice. Therefore, the thesis puts into evidence its influence on calibration and signal uncertainty and the technical solutions that can be adopted to limit the phenomenon. Among the strain gage measurements, the torque measurement on the shaft is the most uncertain. However, many studies have shown that an accurate torque measurement can provide much information about the WT’s health. Available solutions more accurate, like inline torque sensor, are invasive and inappropriate. This thesis, in its second part, analyses a novel, contactless torque measurement system consisting of two shaft-mounted zebra tapes and two optical sensors mounted on stationary rigid supports. The performance of the system has been analysed experimentally on a test bench. The results show good agreement with reference measurements from an in-line, invasive torque transducer with an uncertainty of ±0.3%. Finally, a feasibility analysis and a system scale-up design for two typical WTs with different shaft configurations has been performed and shows that the measurement technique is less uncertain when performed on long and slow shafts.
Luna, Collazos Juan Arturo. "Análisis sísmico y diseño estructural de un edificio de concreto armado en esquina de cuatro pisos y un semisótano con problema torsional". Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2020. http://hdl.handle.net/10757/648681.
Texto completo da fonteIn this thesis the extreme torsional problem of a four-story corner building and a basement is analyzed. The buildings in controlled corners have a commercial architectural design, which takes advantage of the perimeter adjacent to the street to put windows and screens. However, this architectural design does not take into account structural irregularities. One of the irregularities is the torsional one. The torsion is a consequence of the eccentricities between the Mass Center (CM) and the Rigidity Center (CR) in both axes. For the present thesis, the following hypothesis is proposed: “The case under study presents extreme torsional irregularity given its architecture and its corner location. This irregularity is not allowed according to Standard in Buildings category "C" and with zoning 4, so the rigidity in critical areas will be increased. This rigidity does not depend on the increase of large length of plates but on its thickness and its location within the structuring For its demonstration, five models are proposed, which are analyzed seismically using Technical Standard E030-2016, taking as a starting point the architectural plans and a basic structuring; then choose one of the five models and make the corresponding structural design of all the elements of the building”. In addition, the thesis has as an added value the torsional analysis under three technical standards of earthquake resistance of the years 2003, 2016 and 2018, with the objective of finding substantial differences between them. In addition, it is proposed to perform the respectful Time-History analysis of the solution model.
Tesis
Garami, Boris. "Dynamický model harmonické převodovky". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-254390.
Texto completo da fonteKurt, Arda. "Boundary Element Method Formulation And Its Solution In Forward Problem Of Electrocardiography By Using A Realistic Torso Model". Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12607232/index.pdf.
Texto completo da fontehowever, when it is distorted by some abnormalities, the results will be fatal. Electrocardiography (ECG) is the technique dealing with the acquisition and interpretation of the electrical potentials recorded at the body surface due to the electrical activity of the heart. This can be realized by using one of the two approaches utilized in ECG namely
forward and inverse problems. The former one entails the calculation potentials on the body surface from known electrical activity of the heart and the latter one does the reverse. In this thesis, we will construct the body surface potentials in a realistic torso model starting from the epicardial potentials. In order to solve the forward problem, one needs a geometric model that includes the torso and the heart surfaces, as well as the intermediate surfaces or the intervening volume, and some assumptions about the electrical conductivity inside the enclosed volume. A realistic torso model has a complex geometry and this complexity makes it impossible to solve the forward problem analytically. In this study, Boundary Element Method (BEM) will be applied to solve the forward problem numerically. Furthermore, the effect of torso inhomogeneities such as lungs, muscles and skin to the body surface potentials will be analyzed numerically.
Pook, Torsten [Verfasser], Henner [Akademischer Betreuer] Simianer, Henner [Gutachter] Simianer, Timothy Mathes [Gutachter] Beissinger e Hans-Peter [Gutachter] Piepho. "Methods and software to enhance statistical analysis in large scale problems in breeding and quantitative genetics / Torsten Pook ; Gutachter: Henner Simianer, Timothy Mathes Beissinger, Hans-Peter Piepho ; Betreuer: Henner Simianer". Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2019. http://d-nb.info/1199608254/34.
Texto completo da fonteDerenthal, Ulrich. "Geometry of universal torsors". Doctoral thesis, [S.l.] : [s.n.], 2006. http://webdoc.sub.gwdg.de/diss/2006/derenthal.
Texto completo da fonteZemzemi, Nejib. "Étude théorique et numérique de l'activité électrique du cœur: Applications aux électrocardiogrammes". Phd thesis, Université Paris Sud - Paris XI, 2009. http://tel.archives-ouvertes.fr/tel-00470375.
Texto completo da fonteLin, Wen Tzao, e 林文藻. "Torsion Crack Problems of Thick Composite Laminates". Thesis, 1993. http://ndltd.ncl.edu.tw/handle/83863906187501025839.
Texto completo da fonteFili, Paul Arthur. "Orthogonal decompositions of the space of algebraic numbers modulo torsion". Thesis, 2010. http://hdl.handle.net/2152/ETD-UT-2010-05-1416.
Texto completo da fontetext
Chiu, I.-Cheng, e 邱益成. "The problems of the torsion and the conductivity for composite elliptical cylinder". Thesis, 2003. http://ndltd.ncl.edu.tw/handle/33886551507075441808.
Texto completo da fonte國立成功大學
土木工程學系碩博士班
91
This paper discused that after the composite confocal elliptical cylinder bearing torsion, the cross-section''s actions ,meat warping function of composite confocal elliptical cylinder. And, the two dimensions metrix which have the compsite confical elliptical inclusions with heat potential to find their potential and courrent''s actions. We can use continuity of boundary condition for two continuos confocial ellipical to construct the relation of the stuck of matrix to supply the methold to solve this kind of problems. Because of the conveninet. We ask the composit confocal elliptical with strong layers or weak layers for their warping functions. Except, we ask the confocal elliptiacl relations between inermost layer''s courrrent and the boundary of the potental''s order.
Amarnath, S. "Axisymmetric Contact Problems In Composite Elastic Media". Thesis, 1995. https://etd.iisc.ac.in/handle/2005/1630.
Texto completo da fonteAmarnath, S. "Axisymmetric Contact Problems In Composite Elastic Media". Thesis, 1995. http://etd.iisc.ernet.in/handle/2005/1630.
Texto completo da fonteHe, I. L., e 何易霖. "Solving the elastic torsion problems with arbitrary bars by the meshless regularized integral equation method". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/47543961361009582469.
Texto completo da fonte國立臺灣海洋大學
機械與機電工程學系
94
Abstract We treat the ill-posed system of linear equations by a regularization method to transform it to a linear stiff differential equations system. In order to overcome the difficulty of numerical instability, Liu【11】has combined the nonstandard finite difference method into the group-preserving scheme (NGPS) to obtain a stable numerical method for stiff equations. This paper applies the NGPS on the resulting differential equations obtained by adding a differential term on the left-hand side of linear equation, and proves that the new algorithms are unconditional stable. To increase the accuracy, the L-curve is used to select suitable regularization parameter. Several numerical examples are examined and compared with exact solutions revealing that the new algorithms have better computational efficiency and accuracy even for highly ill-conditioned linear equation with a large perturbation of the given data. Then, we consider using NGPS for solving following problems. The solutions of the torsion problem of uniform bars with arbitrary cross-section are presented by the first kind Fredholm integral equation along a selected circle. Then we consider the Lavrentiev regularization and Tikhonov regularization to treat the ill-posed problem. The termwise separable property of kernel function allows us to obtain a two-point boundary value solution. Numerical examples show the effectiveness of the new methods in providing excellent estimatesof the unknown data from the given boundary conditions. Keywords: Laplace equation, Arbitrary domain, Elastic torsion, Fredholm integral equation, Lavrentievregularization, Fourier series
Linß, Torsten [Verfasser]. "Layer adapted meshes for convection diffusion problems / Torsten Linß". 2007. http://d-nb.info/988207265/34.
Texto completo da fonteLiao, Chia-Feng, e 廖家鋒. "Applications of New Error Estimation Technique in Torsion and Anti-plane shear Problems with Multiple Inclusions". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/58186825440773168314.
Texto completo da fonte國立宜蘭大學
土木工程學系碩士班
100
In this thesis, we apply the developed new error estimation technique in boundary element (BEM) and the Trefftz method to estimate the numerical error which is formed in solving real engineering problems. Previous literatures authors, Chen (2010) and Jhong (2011) did not apply this technique in the real engineering problems. Therefore, this thesis will extend this technique to estimate the error caused by using BEM and Trefftz method for solving torsion problem and anti-plane shear problem with inclusions. The main characteristic of this technique is that the exact solution is unnecessary. By creating an auxiliary problem that the governing equation, domain shape and boundary condition type are the same as original problem, we can obtain the optimal number of elements in the BEM and the optimal number of collocation points in the Trefftz method. Finally, several real cases in literatures are taken to demonstrate the accuracy of the proposed estimation technique applied in real problem.
Dao-Long, Chen, e 陳道隆. "A study on mechanical problems of nanoscopic micro-structures under tension, compression and torsion by molecular dynamics theory". Thesis, 2001. http://ndltd.ncl.edu.tw/handle/30423327519791394547.
Texto completo da fonte國立成功大學
機械工程學系
89
The mechanical behaviors of nanoscopic structure of copper are studied by molecular dynamics simulation, and the results are compared with bulk material. In this study, the face center cubic structure of copper crystal is established as the experimental samples. The Gear’s fifth order predictor-corrector algorithms is adopted to calculate the positions, velocities and accelerations of atoms under displacement condition, while the interactions of atoms are dealt with Verlet’s neighbor lists and Morse’s potential. These computer simulations contain tree parts. The first part is to study what difference of stress and strain on the nanostructure and bulk structure of copper with vacancies under tensile. The second part is to study the mechanical behaviors of perfect nanostructure and bulk structure of copper under compression. And the third part is to study the mechanical behaviors of perfect nanostructure and bulk structure of copper again under torsion. These results will be compared with the behaviors in macroscopic world. After a series of computer simulations, we find: (1) the pre-stress in microscopic world shouldn’t be ignored, (2) the rate of strain should be larger than a specific value when simulating the behaviors of nanostructure and bulk structure, (3) for nanostructure with vacancies, the stresses are decreasing while the number of vacancies are increasing, and the bulk structure behaves in the same way except perfect crystal copper with crack, (4) the curves of stress-strain of bulk with periodic boundary conditions are more fluctuant than nanostructure, and different from the behavior in macroscopic world, (5) in compression test, the stress-strain curves will approach to a certain fixed curve while the strain rate is large for both nano- and bulk- structure; on the other hand, the curve of stress-strain becomes unstable while the strain rate is small, (6) in torsion test, the stresses of nanostructure will decrease while the torsion rate is increasing, but it is contrary for bulk structure. The results will help us to clarify the difference between macroscopic continuum and microscopic molecular dynamics in various tests, and gives us some new insights into the mechanical behaviors of nanostructure.
Sung, I.-Cheng, e 宋易澄. "Null-field integral equation approach for solving torsion problems of a circular bar with coated fibers or cracks". Thesis, 2016. http://ndltd.ncl.edu.tw/handle/03633984710584678311.
Texto completo da fonte國立臺灣海洋大學
河海工程學系
104
In this thesis, the null-field integral equation approach in conjunction with the degenerate kernel is used to solve the torsion problems of a circular bar with coated fibers or cracks. The degenerate kernel is employed to substitute the closed-form fundamental solution in the integral equations. In order to fully capture the geometry property, the boundary densities are expanding by Fourier series and eigenfunction expansion for circular boundary and elliptical boundary, respectively. For a circular bar with coated fibers, there are some difficulties on directly analyzing the bar since it has different materials in the bar. By using the technique of taking free body, the bar could be decomposed into three parts. One is a circular bar with circular holes, another is multiple individual circular-ring coatings, and the other is multiple circular fibers. After collocating points on each boundary and satisfying the continuity of displacement and equilibrium of force between interfaces, the unknown coefficients of Fourier series or eigenfunction can be determined by a linear algebraic system. For the problem of cracks in a bar, we adopt the limiting process of approaching the semi-minor axis of elliptical hole to be zero to simulate cracks. Finally, several numerical examples are employed to verify the feasibility and validity of the proposed approach. Besides, the partially and totally neutral behaviors for the composite bars are numerically analyzed.
Korneffel, Torsten [Verfasser]. "On combinatorial search problems which involve graphs / vorgelgt von Torsten Korneffel". 2007. http://d-nb.info/984062386/34.
Texto completo da fonteHein, Torsten [Verfasser]. "Analytische und numerische Studien zu inversen Problemen der Optionspreisbildung / vorgelegt von Torsten Hein". 2003. http://d-nb.info/969860986/34.
Texto completo da fonte