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Tractor cabin skelet optimization
Saňák, Stanislav ; Prokop, Aleš (referee) ; Řehák, Kamil (advisor)
This thesis addresses the issue associated with the design of the tractor cabin frame. Agricultural machinery, including tractors, is utilized for work in highly challenging conditions such as fields or forest terrains, characterized by uneven, hilly, and often unpaved surfaces. Working in such extremely hazardous environments poses a significant challenge, especially for the operators of these machines. It is very common for drivers to lose control of the vehicle while navigating such terrain, resulting in the tractor tipping over on its side or roof, and in worse cases, experiencing repeated rollovers due to inertia. In such situations, the presence of a protective frame around the tractor cabin is the only possible means of crew rescue. However, the rollover of such a vehicle imposes extreme stress on the cabin frame due to the weight of the tractor and often its cargo. Historically, rollovers have been the leading cause of accidents resulting in fatalities of tractor crews, which prompted the establishment of standards aimed at reducing this type of accident. Tractors are tested against these critical situations to ensure the maximum possible crew safety. Nowadays, every manufactured tractor must comply with these tests. Since these tests are of a destructive nature, it is more cost-effective and time-efficient to first conduct tests using numerical simulations, within which the tractor cabin is optimized to successfully pass the given tests. The actual test is then performed on the final, already optimized cabin frame. In this study, a numerical simulation using the finite element method was conducted on the tractor cabin skeleton for the ROPS (Roll-Over Protective Structure) test, which simulates the tractor overturning. Based on the simulation results, optimizations were made to the cabin that were necessary to pass this test, which consists of several load cases. The optimized cabin frame was subsequently subjected to a basic dynamic analysis (modal analysis). This analysis identified the natural frequencies of the cabin that could be excited in the event of typical excitations acting on this structure (road surface irregularities, vibrations from the engine unit, and so on). Finally, based on real values obtained from experimental measurements, a harmonic analysis was performed. This analysis monitored the response of the frame to excitations corresponding to actual excitations from the engine unit.
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Strength Analysis of Turbocharger Rotor of Stationary Internal Combustion Engine
Kejval, Dan ; Kudláček, Petr (referee) ; Novotný, Pavel (advisor)
Turbocharger rotors are highly stressed components exposed to significant thermo-mechanical loads. This thesis provides a literature review of this issue concerning turbocharger rotors and focuses on the thermal field analysis and structural analysis of the turbocharger rotor of a stationary internal combustion engine under different steady-state operating conditions, especially under maximum thermo-mechanical load. The analysis was conducted using Ansys Mechanical software, which allows for the calculation of the thermal field as well as the identification and evaluation of critical areas of the rotor using the finite element method. The result of the thesis is an assessment of the rotor's safety, including the risk of loosening the rings preloaded on the rotor shaft.
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Verification of Numerical Simulation Using a 3D Optical System for Measuring Deformations
Zakl, Alexandr ; Peterková, Eva (referee) ; Řiháček, Jan (advisor)
This master’s thesis discusses the current state of optical metrology and its place in manufacturing and optimization of parts made by deep-drawing technologies. First part is devoted to building a solid knowledge base in different fields that this thesis draws from. These fields are Optical Metrology, deep drawing of sheet metal and simulations using finite elements method. Subsequently, in the experimental part there are chapters dedicated to Measurement and creation of material models and measurement of grid markings on deep-drawn parts provided by ACO Industries, measured by photogrammetric system from German Company GOM metrology. Additionally, for reference to the measurement, FEM software called PAM-Stamp is used to simulate and predict the final state of the parts after manufacturing. Furthermore, optical metrology was used during creation of material models, data supplied by this analysis was used as an input for the simulations. The last chapter then deals with the evaluation and comparison of measured and simulated data and drawing conclusions about the reliability of optical systems and modern technologies in technical practice.
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Utilization of finite fracture mechanics for correction of fracture toughness measurement on samples with various notch root geometry
Dohnal, Petr ; Majer, Zdeněk (referee) ; Ševeček, Oldřich (advisor)
The work deals with the use of numerical simulations and the theory of finite fracture mechanics for the analysis of conditions for the formation of a crack in a ceramic test sample with a notch (loaded by four-point bending) and possible ways of correcting the fracture toughness determined experimentally on samples with different notch root radius. For this purpose, a parametric calculation model was created to simulate the fracture toughness test by four-point bending. In the first step, the calculation of the critical force at which a crack occurs in a test specimen with a rounded notch and its subsequent unstable propagation through the remaining cross-section of the specimen was debugged. For this purpose, the finite element method (FEM) and the coupled stress-energy criterion were used. In the next step, the procedure of calculation of fracture forces was also applied to a set of experimental samples in order to compare the numerical prediction with experimentally measured values. Two methods of correction of the fracture toughness determined experimentally are also proposed in the thesis. One uses for a correction of the measured values numerical calculation using the coupled stress-energy criterion. In the second case, a correction function was derived using numerical simulation, which no longer needs an FEM calculation for its future use. Correction of the measured fracture toughness using the function proved to be better but not completely effective for the entire range of investigated notch root radii. When comparing with other correction functions found in the literature, it can be stated that the correction procedure proposed in the work provides a better agreement with the real value of the fracture toughness of the given material up to a certain value of the notch root radius.
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Design of an industrial robot with six degrees of freedom
Štefek, Ondřej ; Štěpánek, Vojtěch (referee) ; Knoflíček, Radek (advisor)
The diploma thesis deals with the design, production and construction of robots with six degrees of freedom and a serial kinematic structure. In the beginning of the thesis, the individual types of robots, used gearboxes, energy media are described, and the principle of direct and inverse robot kinematics is outlined here. In the next chapters, the system approach of the robot, the selection of the optimal variant of creation, and then the kinematics and dynamics of the robot, which further follows on from the principle of the creation of castings, the design nodes of the robot and its electrical engineering and the programming of the control system, are analyzed. For the pinions and the shaft of the fifth axis, a safety analysis is carried out with respect to the limit state of elasticity. This robot design is then financially compared with a commercially available industrial robot. For the robot, among other appendices, drawing documentation, an electrical wiring diagram and a safety analysis of the robotic workplace have been prepared. The robot and the related robotic workplace are physically built in the workshops of the Institute of Production Machines, Systems and Robotics in Brno.
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Analysis of the procedure for identifying potentially dangerous locations of weld joints in thin-walled metal structures during life assessment
Doležel, Daniel ; Pavlík, Ondřej (referee) ; Vosynek, Petr (advisor)
Hodnocení únavy svarů u tenkostěnných kovových konstrukcích je klíčové pro zajištění integrity navrhovaných konstrukcí. Navzdory zavedeným kritériím a S-N křivkám může být analýza životnosti svařovaných spojů u geometricky komplexních součástí značně komplikovaná. Hlavní překážkou je identifikace kritických míst z hlediska únavy pro detailní výpočet, což může být časově náročné i při využití metody konečných prvků (MKP). Tato práce podrobně zkoumá hodnocení únavy svarů, zahrnuje vhled do relevantní literatury, komerčních řešení a praktický kontext norem železničního průmyslu a směrnice FKM. Významným přínosem práce je vývoj automatizovaných FEMAP API programů pro MKP software Siemens FEMAP, které usnadňují proces analýzy. Tyto programy šetří čas a úsilí tím, že umožňují zjednodušenou analýzu založenou na konceptu lokálního nominálního napětí (local nominal stress) v souladu se směrnicí FKM. Metodika, podpořená vyvinutými programy, je v této práci popsána a prakticky demonstrována. Praktické přínosy této práce spočívají v poskytnutí alternativy ke komerčním softwarům, za účelem zvýšení efektivity analýzy životnosti svarů v kontextu konstukčních návrhů.
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Stochastic finite element method to solve 2d problems
Liščák, Milan ; Boháč, Petr (referee) ; Návrat, Tomáš (advisor)
The thesis focuses on programming of algorithms based on the finite element method (FEM) and the stochastic finite element method (SFEM) used for deformation and stress analysis of truss and plane stress problems. All the codes are developed using a free to use program PyCharm. For both trusses and plane stress problems, the algorithm is illustrated with a simple problem and verified on a more complex one. The results from the FEM calculations are validated using results from ANSYS Workbench. The computed displacements and reaction forces are equal to ANSYS results for all solved cases. There are minor deviations in the stress calculations for plane stress problems. The reason for this is unknown, as ANSYS does not provide an exact methodology for stress computing. In SFEM calculations, the values of Young’s modulus, yield strength and load forces are normally distributed. The codes are run repeatedly and based on the variability of the results the probability of failure is calculated.
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Traveling and slewing mechanism of the crane trolley of a 30-ton overhead stacking crane
Zicho, Jan ; Bartušek, Filip (referee) ; Škopán, Miroslav (advisor)
This diploma thesis deals with the design of some mechanisms of the overhead stacking crane working with steel coils in the steelworks. The main point of this work is to create technical documentation consisting of the design of the traveling and slewing mechanism of the 30-ton crane trolley and the traveling mechanism of the crane cabin. The technical documentation also includes the stress calculation of the main trolley frame using FEM and drawing documentation of the main parts of a crane trolley. This master´s thesis was created in cooperation with KPC a.s.
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Comparison of FEM models using 1D and 2D elements used to flutter analysis
Zubaľ, Filip ; Navrátil, Jan (referee) ; Šplíchal, Jan (advisor)
The diploma thesis deals with flutter, which is one of the most dangerous dynamic aeroelastic phenomena in aviation. The work includes the creation process and subsequent flutter analysis of two FEM models of the wing of the BUT 051 Ray experimental aircraft. The goal of the work is to compare individual FEM models and determine the critical flutter speed, to evaluate the effectiveness and usability of FEM models created by 1D or 2D elements.
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Stress analysis and modelling of adhesive bonded joints with the use of Finite Element Method
Trubíniová, Karolína ; Horák, Marek (referee) ; Katrňák, Tomáš (advisor)
This bachelor’s thesis deals with the analysis of adhesive joints used in the aerospace industry by numerical solution using finite element method. The research section is focused on introduction to the topic of adhesive joints, the advantages and disadvantages they bring and their use in aerospace industry. The shear strength test using analytical approach is also part of this work. The practical part is focused on creation of 2D and 3D models of single lap joint test specimen and the subsequent strength analysis in MSC.Patran and MSC.Nastran. The output of this work consists of linear analysis of 2D and 3D problems, a non-linear analysis of 3D problem and comparison of results obtained by these methods.
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