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Strain and stress analysis of the car buffer zone under impact loading
Nedělka, Pavel ; Obdržálek, Vít (referee) ; Vrbka, Jan (advisor)
The master thesis deals with a stress-strain analysis of the front crash structure of a race car by using the finite element method. The structure is loaded by an impact loading. This type of analysis belongs to the transient analysis so the explicit formulation of the finite element method is used. The LS-DYNA software was used for calculations. The goal of this thesis is to express the influence of the crash structure to the change of the car's kinetic energy as well as the amount of absorbed energy in case of frontal impact.
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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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FEM for machining simulation
Vojtek, Aleš ; Madaj, Martin (referee) ; Zouhar, Jan (advisor)
The introduction to turning basics, chip separation process, cutting force generation and description of the finite element method. With this knowledge, a cutting simula-tion of AISI 1045 steel was done for 3 different rake angles, which was simplified by using an orthogonal machining model. The next simulation was cutting of AISI 6150 steel with the use of a 3D model of the grooving insert. The results of these simulations were then compared to the experimental results, and feasibility of finite element method was determined together with future recommendations for acquiring more pre-cise results.
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Verification of nonlinear material models
Prokš, Tomáš ; Němec, Ivan (referee) ; Hradil, Petr (advisor)
The bachelor thesis deals with verification of nonlinear material model of soil FHWA SOIL during shear test. The nonlinear problem was being solved by software LS-DYNA using explicit formulation of finite elements method. The values of horizontal displacements during the direct shear test were compared with the results listed by the developer of the material. The considerable difference in the results led to focusing on the settings of the material model and influence of application of load, geometry and type of finite elements on the monitoring values.
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