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Verification of nonlinear material models of concrete
Král, Petr ; Němec, Ivan (referee) ; Hradil, Petr (advisor)
Diploma thesis is focused on the description of the parameters of nonlinear material models of concrete, which are implemented in a computational system LS-DYNA, interacting with performance of nonlinear test calculations in system LS-DYNA on selected problems, which are formed mainly by simulations of tests of mechanical and physical properties of concrete in uniaxial compressive and tensile on cylinders with applying different boundary conditions and by simulation of bending slab, with subsequent comparison of some results of test calculations with results of the experiment. The thesis includes creation of appropriate geometric models of selected problems, meshing of these geometric models, description of parameters and application of nonlinear material models of concrete on selected problems, application of loads and boundary conditions on selected problems and performance of nonlinear calculations in a computational system LS-DYNA. Evaluation of results is made on the basis of stress-strain diagrams and load-displacement diagrams based on nonlinear calculations taking into account strain rate effects and on the basis of hysteresis curves based on nonlinear calculations in case of application of cyclic loading on selected problems. Verification of nonlinear material models of concrete is made on the basis of comparison of some results of test calculations with results obtained from the experiment.
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Fatigue life of crankshaft
Wolf, David ; Kučera, Pavel (referee) ; Vopařil, Jan (advisor)
This thesis is focused on the crankshaft as one of the most dynamically stressed component of internal combustion engines. At the beginning describes in the wider context how is the crankshaft of internal combustion engines strained. Then it considers individual parts of crankshaft, which are affecting its construction in terms of fatigue life. And in the last section describes the different ways to eliminate the damage caused by cyclic loading and modern methods of fatigue life prediction of crankshafts.
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The effect of cyclic loading assessment on the deformation characteristics of hardened concrete
Potočková, Michaela ; Kocáb, Dalibor (referee) ; Misák, Petr (advisor)
This thesis deals with the influence of multiple cyclic loading on the deformation characteristics of hardened concrete. The influence on static modulus of elasticity in compression was studied. In this thesis deformation during multiple cyclic loading test was measured. Afterwards, from the test results the static modulus of elasticity in pressure was defined. The main output of this research is grafical and percentual representation of decrease of static modulus of elasticity values in compression in dependence of increasing number of cycles.
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Geo-oriented mathematical modelling: multiphysics and multiscale
Blaheta, Radim
This contribution is aimed at a brief introduction to two important aspects of nowadays geo-oriented mathematical modelling: multiphysics and multiscale. Moreover, these types of modelling are illustrated on problems currently solved at the Institute of Geonics AS CR.The multiphysics means modelling of coupled physical phenomena. In the case of the geotechnical engineering, it is typically modelling of coupled thermo-hydro-mechanical (THM) processes, in other engineering branches, we can consider similar models, e.g. coupling of electric and mechanical phenomena. The modelling of coupled processes is particularly involved in modelling of sealing and plugging effects of bentonite barriers used in the design of underground repository of spent nuclear fuel. At present, the team at the Institute of Geonics is involved in the solution of Task A of the Decovalex 2015 project aimed at modelling in-situ SEALEX experiments, which were performed in Tournemire underground laboratory in France.
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