|
|
A simplified model of the pad deformation of the journal bearing
Janiš, Tomáš ; Cabaj, Gabriel (referee) ; Pokorný, Jan (advisor)
The presented bachelor thesis deals with the calculation of deflection of a pad of a hydrodynamic radial bearing with tilting pads. This type of bearing is described by its characteristics, which are determined by means of simulations. Knowledge of these characteristics is important for predicting the behaviour of bearings in service and for the design of equipment using these bearings. The bearing characteristics are strongly dependent on the thickness of the lubricating film. This is in fact very thin and is therefore affected by the slightest deflection of the pad. This paper therefore deals with the calculation of pad deflection. With this calculation, the effect of pad deflection can then be included in downstream simulations to determine the bearing characteristics. The inclusion of this effect results in more accurate simulations. For this reason, a computational model of bearing pad deflection is developed. This model is based on the differential equation of the deflection line assuming small deformations. The temperature effects due to lubricant heating and the pressure effects due to bearing pad loading are included in this calculation. The deflection results from these loads are further compared with the results obtained by the finite element method. This comparison did not achieve the required compliance.
|
|
|
Topological optimisation of the turbocharger electric actuator bracket
Směšný, Jan ; Kudláček, Petr (referee) ; Novotný, Pavel (advisor)
Topology optimization utilizes mathematical methods to develop the most efficient components in terms of mechanical properties and weight. Nowadays, it is a commonly used tool for designing components not only in the automotive, aerospace, and space industries. This work deals with the topological optimization of a metal bracket used to attach an electric actuator to a turbocharger. The turbocharger assembly is subjected to external influences, the most significant of which are vibrations from the engine. The program Ansys Workbench was used for modal and topology optimization calculations. The goal of the optimization was to minimize weight and maximize the natural frequency. The optimization takes into account a simple manufacturing method using conventional techniques (shearing & bending), which will remain the same for the optimized component. Additional care is taken to ensure, that the natural frequency of the bracket-actuator system is above the excitation frequency from the engine. The final optimization revealed that by appropriately removing material, the component's weight can be reduced by 22% without significantly degrading its dynamic properties.
|
|
|
Optimizing a highly loaded components for motorsport
Šišpera, Petr ; Prokop, Aleš (referee) ; Řehák, Kamil (advisor)
This thesis deals with optimizing the rear suspension of the fifth generation Honda Civic for motorsport application. The goal is to reduce weight while increasing stiffness and precision in wheel control. The work is based on the properties of serial components, which are analyzed using FEM analysis in the Ansys program. Load conditions are calculated from vehicle dynamics and the loading of individual arms from the suspension kinematics. Suspension components are first modeled and analyzed and this data provides input information for optimization. Individual components are initially topologically optimized, based on which models are created for deformation stress analysis. The properties of the serial parts are ultimately compared to optimized ones under the most critical loading conditions and the result of the work is an optimized suspension system with lower weight and higher stiffness.
|
|
|
Reinforced concrete slab of the administrative part of the depository
Jirků, Jan ; Strnad, Jiří (referee) ; Požár, Michal (advisor)
The bachelor's thesis focuses on the design and assessment of a reinforced concrete locally supported monolithic slab below the first floor of a library depository. The thesis also includes the design and assessment of a column and a prefabricated staircase. The calculation of internal forces was performed using the finite element method in the SCIA Engineer program, and its accuracy was verified by a manual calculation using the method of moment summation. The slab was assessed for ultimate limit state and serviceability limit state. Finally, based on the structural calculation, reinforcement drawings for the individual structures were prepared.
|
|
|
Stress-deformation analysis of the indoor basketball construction
Kubíček, Daniel ; Kovář, Jaroslav (referee) ; Fuis, Vladimír (advisor)
The topic of this thesis is stress-strain analysis of a basketball structure in a gymnasium. This structure is divided into two parts. One part is modeled as a spatial bar system. The other part is modeled as a plane bar system. The first part of the paper deals with the research on the use of bar systems in sports. This is followed by the development of analytical computational models of the spatial and plane bar systems. These models are then used to calculate three different loading conditions. Subsequently, the models are developed for numerical solution. In the last part of this work, the analytical solution is verified by the numerical solution.
|
|
|
Determination of residual stresses by hole-drilling method considering finite body boundaries
Began, Jakub ; Ščerba, Bořek (referee) ; Halabuk, Dávid (advisor)
The diploma thesis analyses the impact of the finite dimensions of a body on residual stresses by means of the hole-drilling method which was derived for bodies of dimensions large enough not to affect the measurement. To assess the impact of the finite dimensions of a body on measured residual stresses, a computational model simulating the hole drilling method was created using the finite element method. The assumptions made during the creation of the computational model included a desired geometric shape and an uniform residual stresses along the depth of the drilled hole. The computational model was subsequently parameterised so that it could be used to simulate different combinations of the finite dimensions of a body, whose impact on measured residual stresses was analysed. In the next part of the thesis, the impact of the biaxiality of residual stresses on the accuracy of their measurement was assessed. Subsequently, three correction algorithms were proposed to minimise the errors of measured residual stresses caused by the finite dimensions of a body. The first correction algorithm is supposed to correct calibration coefficients, the second one to correct input strains, and the third one to correct the assessed residual stresses. In the last part of the thesis, the individual correction algorithms were tested and compared. The outcomes of the diploma thesis suggest the possibility to correct the errors in the analysed residual stresses due to finite dimensions of a body, on the condition of a desired geometric shape and an uniform stresses along the depth of the drilled hole.
|
|
|
Stress analysis of a connecting shackle
Bodo, Ondrej ; Hrstka, Miroslav (referee) ; Vaverka, Jiří (advisor)
The bachelor thesis deals with the stress analysis of a selected real connecting shackle using an analytical model based on the beam theory. In the first part, the basic classification of the used types of shackles according to their shape, removable pin or used materials is presented. The following part briefly presents the mechanical theory of linear elastic bars and beams complemented by the theory of curved beams, on the basis of which two analytical models differing in the use of symmetry are developed in the practical part. In both cases of the analytical models, the results with or without the use of the theory of curved beams are also compared, thus proving its applicability. The analytical section also includes an analysis of one ear of the shackle. Finally, the results obtained by the analytical solution are verified by computational modelling using the finite element method in ANSYS Workbench 2023 R2 software, where, in addition to the verification of the model calculated in the analytical solution, a more realistically distributed loading of the shackle is also considered, together with the verification of the maximum stresses of the ear using 3D solid elements.
|
|
|
Topology optimization of frame
Kartaš, David ; Pokorný, Přemysl (referee) ; Zeizinger, Lukáš (advisor)
This bachelor thesis deals with the problem of topological optimization of machine components, specifically frame optimization. The first part describes the different methods and techniques of topological optimization. The second part contains the actual solution of topological optimization on a selected frame. In conclusion, the results of this work are summarized and evaluated, and finally compared with the baseline frame.
|
|
|
Strain and stress analysis of the effect of cementoplasty after intralesional resection of metastasis in long bones
Hrušková, Zuzana ; Kovář, Jaroslav (referee) ; Boháč, Petr (advisor)
This final thesis deals with the stress – strain analysis of the impact of cementoplasty on the femur after intralesional resection of bone metastasis. The first part provides a brief review introducing the issue of using computational modeling in static analyses of the femur. The second part describes the knowledge necessary to understand the issue, including the anatomy of the femur, the structure of bone tissues, the procedure of cementoplasty, and the basic properties of bone cements. The third part details the process of creating the computational model – geometry creation, finite element meshing, material properties and the selection of loads and boundary conditions. The final part presents and analyzes the results of the equivalent stain of the femur and evaluates the results based on Frost's hypothesis.
|
|
|
Study of crack retarders geometry modification effect on integral structural panel stability with the use of Finite Element method
Moštěk, Daniel ; Augustin, Petr (referee) ; Katrňák, Tomáš (advisor)
The master’s thesis concerns itself with evaluating the impact of four dimensional parameters of a specific type of crack retarder on improving the compressional buckling strength of an integral wing panel, using the finite element method. The improvements in buckling strength were particularly assessed with concerns to the added mass of the crack retarders. The crack retarders are composed of a so-called terminal section and so-called side branches. The thesis includes a literature review on the buckling of skin-stringer panels and an overview of crack retarder types. In the practical part of the thesis created FEM models of the examined variants are described along with the achieved results, which are subsequently evaluated. It was concluded that the examined parameters related to the terminal section significantly influence the increase of buckling strength of a given variant and are efficient concerning added mass. On the other hand, the examined parameters related to the side branches were deemed less significant and their alteration was inefficient in terms of added mass.
|
guest ::
