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Review of methods for local contact search
Kopačka, Ján ; Gabriel, Dušan ; Plešek, Jiří
The local contact search is a numerical procedure of a contact algorithm which is used for computing of a penetration vector between so-called master and slave segments of contact surfaces. There are several approaches. In this paper the minimum distance problem between the master segment and the integration point of the slave segment is used. For quadrilateral elements this approach leads to the system of two nonlinear equations. For its solution several methods was tested (Newton-Raphson method, least square projection, method of steepest descent, Broyden's method, BFGS method, DFP method and simplex method) and efficiency was compared.
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Modelování dvounohého robotu: Kinematické numerické modely
Grepl, Robert
Modelling of kinematics is one of the basic task related to walking machines. In this paper, we present the buildingof numerical computational forward and inverse kinematic models of bipedal robotic leg. Models are implementedin Matlab/Simulink/SimMechanics environment. All computations are numerical only, so no analytical model isformed. Advantages and disadvantages of such approach are discussed. The role of this way of modelling in wholedesign and development process is also mentioned.
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Numerický model celodřevěného konstrukčního spoje
Staňková, Eliška
Part of bachelor's thesis is numeric simulation of several testing variants of wholewood carpentry joints during mechanical strain. As a type of test was used 3 and 4 spots bend for symmetric and asymmetric loaded joint.There were tested a joints with two different dimensions. Purpose of this test is elaboration, evaluation and comparison of joint behavior. For simulations is monitored the process of Ansys Workbench tool, that means, Individual steps from creation of geometric model trough networking, defining of material attributes, determination of boundary conditions solution to exportation of results. Basic joint designs were taken from destruction tests ongoing within "Design and evaluation of historical construction carpentry joints" project, which followed up the design of wholewood joints and destruction tests. This project is showing complex joint response by using a method based on finite element method. The results of the project will be used for comparison with experimental data and then used to examine alternatives joints.
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Numerical solution of boundary equations by splines.
Stašek, Petr ; Knobloch, Petr (referee) ; Najzar, Karel (advisor)
Nazcv praee: Aplikace splinu k muncrickemu fcscni okrajovych uloh Autor: Petr Stasek Katcdra (nsta,v): Katedra nnmericke inateniatiky Vetlouci bakalafske prace: Doe. RNDr. Karel Najzar, CSc (vnia.il vedoun'ho: Karel.NajzarKihiiff. euni.cz Abstrakt: V pfedlozeric praci ncjprve delinujeme spliny a uvadime jejich zakladni vlast- uosti a take konstrukci kubickeho splinu, potom so xabyvame intcrpolaci .spliny, uvadime jeji druliy a odvozujeme jakych ehyb se dupustime pfi pouziti interpolaee kubickym splinein. Vc druhe kapitolc se zabyvamc aplikaci splinu k fescni obyccjnych difcrcncialnieh rovnic, nejprve uvadime diferencialni rovnice .s pocatecni podminkou, ktere fesimc za pomoei kolokacc, potom se zabyvame diferencialniini ulohy s okrajovyini podniinkami v daneui tvaru, ktere fesimc Galerkinovou metodou za pomoci B-y])linu. Ca.stccne se take vcmvjcine stabilite metod. Na zaver uvadirn dva pfiklady jako konkretni aplikaei. Title: Numerical solution of boundary equations by splines Author: Petr Sta.sek Department: Department of Numerical Mathematics Supervisor: Doc. RNDr. Karel Najzar, CSc Supervisor's e-mail address: Karel.NajzarQmff.cuni.cz Abstract: In the present work first we define splines and report their basic properties and construction of cubic spline, then we study interpolation by splines and report...
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Comparison of methods for RGB spectrogram construction of DNA
Postránecká, Tereza ; Provazník, Ivo (referee) ; Kubicová, Vladimíra (advisor)
This thesis discusses about possibilities of construction colour DNA spectrograms and about patterns which can be detected there. Spectrograms as tools of spectral analysis give us a simultaneous view of the local frequency throughout the nucleotide sequence. They are suitable for gene identification or gene regions identification, determination of global character about whole chromosomes and also give us a chance for the discovery of yet unknown regions of potential significance. For purpose of this kind of DNA analysis is possible to use digital signal processing methods. We can apply them on only after conversion of DNA sequence to numerical representation. Selection of correct numerical representation affects how well will be reflected biological features in numerical record which we need for another use in digital signal analysis.
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Material nonlinear solution of structures made of plastics
Weis, Lukáš ; Krejsa,, Martin (referee) ; Králík,, Juraj (referee) ; Kytýr, Jiří (referee) ; Němec, Ivan (advisor)
The presented thesis focuses on static analysis of plastic structures, taking into account nonlinear behaviour of the material depending on the stress. The static analysis is performed using the finite element method. The difference between material linear and material nonlinear approach is illustratively described in the introduction. A shell finite element, which is enhanced by the possibility of further delamination into layers and integration points along its thickness, is suitable to be used for a numerical analysis of a plastic structures. Separate chapters are devoted to the integration of the resulting values over the height of the cross-section. The integration of the material stiffness matrix correctly reflects the emergence of eccentricity. A part of the attention is devoted to the numerical quadrature rules. Next chapter is devoted to material nonlinear models. Two approaches are described: a simpler one, using the isotropic nonlinear elastic model, and more general one, using the orthotropic plastic model. The theoretical description is complemented by the graphic interpretation of the criteria according to the individual authors. A significant portion of this work is devoted to the algorithmization of calculation procedures described in the theoretical chapters. The algorithmization itself is implemented in Fortran language into a dynamic-link library which is part of the software program RFEM 5 which is widely used in engineering practice. A part of the work is a study comparing the performance of the different technologies applicable for the algorithmization of the described issues. The agreement of the theoretical analysis of the material models and subsequent implementation within the RFEM 5 is demonstrated on the example of the bent cantilever. The thermoplastic aboveground tank structure is subject of detailed material linear, and nonlinear analysis respectively. The various approaches are compared on the results of stress, deformation an
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Using Optimization's Algorithms by Designing of Structures
Fedorik, Filip ; Keršner, Zbyněk (referee) ; Haapala,, Antti (referee) ; Dický,, Jozef (referee) ; Kala, Jiří (advisor)
The application of optimization algorithms in the design of many economical and industrial problems currently represents a significant assignment. The development of high-powered computers allows an application of difficult mathematical techniques and physical phenomena to simulate real problems with sufficient accuracy. The optimization techniques used in engineering designs are mostly represented by modified mathematical programming methods with extension of their usability. The aim of the presented thesis "Using Optimization´s Algorithms by Designing of Structures" is to analyze the applicability of optimization procedures which are available in the widely used computing system ANSYS in civil and mechanical engineering practice. The numerical analyses were performed within the frame of multi-extreme, one to three dimensional optimization problems, multi-dimensional problems expressed by minimizing the weight of a truss beam and efficient design of air gap location in wooden studs from the point of view of thermal features of the structure. The analyzed optimization processes are in plurality verified with accurate manual computing and graphical solutions and the accent is put on optimization methods´ possibilities to improve robustness, efficiency and accuracy of the optimization algorithms in civil engineering problems´ designs. The optimization methods represent a suitable approach to improve the efficient design of a wide range of civil and mechanical engineering structures and elements. By combination of their advantages and FEM/FEA method it is possible to achieve very good results, although robustness of the solutions is not guaranteed. The robustness and accuracy of the procedure could be increased by competent exploration of design space and suitable selections of optimization methods´ features.
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