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Analysis of mechanical loads of selected structural parts of the excavator during operation
Busta, Michal ; Maňas, Pavel (referee) ; Vosynek, Petr (advisor)
This thesis is focused on the issue of computational modeling of soil harvesting while using the compact excavator from the company DOOSAN BOBCAT EMEA s.r.o.. The solution consists in creating two computational models in Rocky DEM and Ansys Mechanical. Rocky DEM software is used to solve the disconnection of soil by excavator components using the discrete element method. The outcome includes courses of forces and moments during the particular time of the individual joints of the model that was used. The obtained courses are then applied as an external load to the joint of a selected structural part of the analyzed model using a kinematic model in ANSYS Mechanical. The kinematic model consists of simplified geometry models of individual parts of the excavator arm, and a more detailed geometry model of the analyzed part of the arm. All the parts are connected to each other by rotational bonds representing joints. A static structural analysis of the mechanical stress is performed in ANSYS Mechanical for the prepared model during the simulated process. Finally, the selected structural part is assessed with respect to the elastic limit and fatigue strength.
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Device for filling tap hole of arc furnace
Juda, Lukáš ; Brhel, Jaroslav (referee) ; Malášek, Jiří (advisor)
Diploma thesis describes design and function verification of device for filling tap hole of electric arc furnace with tap hole diameter from 190 mm to 250 mm. The theses includes drive design calculation of chute swinging movement and bearing calculations. Another part of the thesis deals with verification of device functions which it is completed with process description of creating DEM simulation in program YADE. The thesis also includes basic experiments for determination angle of internal friction, angle of repose, coefficient of restitution and angle of material friction on a steel surface. Drawing documentation of selected assemblies is part of the thesis.
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Design Optimization of Bucket Conveyors
Jonák, Martin ; Svěrák, Tomáš (referee) ; Zegzulka, Jiří (referee) ; Malášek, Jiří (advisor)
This thesis deals with a study of methods sufficient to describe the behavior of bulk materials (homogeneous and non-homogeneous) during their transport by bucket elevators in the application focused on the optimization of the bucket shape and also on the optimization of operating parameters of whole elevator. More specifically, this thesis is based on the studying and creating analytical and numerical computational models which are used for description of flows and deformations especially of particulate materials. Firstly, the thesis is focused on the process of discharging the bucket – the relationship among the shape of the surface of a particulate material and geometry, position and movement of the bucket. The beginning and way of discharge of the bucket will be determined. Secondly, the thesis includes the overall computational model of a bucket elevator which is based on discrete element method and presented in the case study. The goal is to determine the limits of some classical physical and mathematical descriptions.
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Mobile separator of the gravel and sand into individual fractions
Bezdíček, Petr ; Mergl, Václav (referee) ; Kašpárek, Jaroslav (advisor)
This thesis focuses on a research analysis of the technology of similar separators, the legislative regulations of the trailers and the conceptual design of the mobile gravel sorter itself. The thesis also includes functional, dimensional and force calculations of the individual nodes of the classifier. The classifier also includes conveyor belts for conveying material up to a height of approximately 1.5 m. Calculations and selection of the necessary drives for certain parts of the machine are also included. Furthermore, the work includes strength FEM calculations of selected structural nodes under different loading regimes. Finally, the DEM simulation of the sorting process in Altair EDEM is discussed. The thesis, including the assembly drawing, also includes a drawing of the weldment subassembly of the separation drum and frame. Selected shop fabrication drawings are prepared for this sub-assembly as a basis for fabrication of selected components.
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Mathematical Modeling of Heat and Mass Transfer in a Rotary Kiln
Kozakovič, M. ; Čada, J. ; Kokavcová, A. ; Havlica, Jaromír ; Huchet, F.
The main objective of this research was to compare the results of the proposed 1D transport model with numerical simulations of mass transport in a direct-heat rotary kiln at laboratory scale. Another objective was to investigate the effect of the number of flights on the formation of an active particle surface in the airborne phase, which enables efficient heat transport. The studied rotary kiln is a low-angle cylinder with a length of 0.5 meter and a diameter of 0.108 meter with regularly arranged flights on the inside. The heat is transported into the rotary kiln by hot air at the inlet. The load in the rotary kiln consists of spherical particles with 1 millimeter diameter. The rotary kiln rotation speed is 21.5 rpm. For each simulation, 20 rotations were performed. The Discrete Element Method implemented in an open-source code LIGGGHTS was used for simulations.Efficient heat transfer is made possible primarily by the large number of particles in the airborne phase, which are heated by the warm air blowing in. To begin with, the number of flights and their geometry were found to be a key parameter controlling the amount of particles in the gaseous regime. It was also found that an area in the right part of the base of the cylinder is formed which is not reached by particles from the flights. This phenomenon is due to the dynamics of particle transport, as the particles are not maintained in the active phase and move rapidly towards the load due to gravity. In conclusion, the effect of this zone is negative, as hot air flows through it without resistance, preventing the system from heating effectively.
Plný tet:  PDF
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Analysis of mechanical loads of selected structural parts of the excavator during operation
Busta, Michal ; Maňas, Pavel (referee) ; Vosynek, Petr (advisor)
This thesis is focused on the issue of computational modeling of soil harvesting while using the compact excavator from the company DOOSAN BOBCAT EMEA s.r.o.. The solution consists in creating two computational models in Rocky DEM and Ansys Mechanical. Rocky DEM software is used to solve the disconnection of soil by excavator components using the discrete element method. The outcome includes courses of forces and moments during the particular time of the individual joints of the model that was used. The obtained courses are then applied as an external load to the joint of a selected structural part of the analyzed model using a kinematic model in ANSYS Mechanical. The kinematic model consists of simplified geometry models of individual parts of the excavator arm, and a more detailed geometry model of the analyzed part of the arm. All the parts are connected to each other by rotational bonds representing joints. A static structural analysis of the mechanical stress is performed in ANSYS Mechanical for the prepared model during the simulated process. Finally, the selected structural part is assessed with respect to the elastic limit and fatigue strength.
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Design Optimization of Bucket Conveyors
Jonák, Martin ; Svěrák, Tomáš (referee) ; Zegzulka, Jiří (referee) ; Malášek, Jiří (advisor)
This thesis deals with a study of methods sufficient to describe the behavior of bulk materials (homogeneous and non-homogeneous) during their transport by bucket elevators in the application focused on the optimization of the bucket shape and also on the optimization of operating parameters of whole elevator. More specifically, this thesis is based on the studying and creating analytical and numerical computational models which are used for description of flows and deformations especially of particulate materials. Firstly, the thesis is focused on the process of discharging the bucket – the relationship among the shape of the surface of a particulate material and geometry, position and movement of the bucket. The beginning and way of discharge of the bucket will be determined. Secondly, the thesis includes the overall computational model of a bucket elevator which is based on discrete element method and presented in the case study. The goal is to determine the limits of some classical physical and mathematical descriptions.
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