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Influence of essential parameters on the radial clearance and stress-strain states in ball bearings
Šperka, Václav ; Vrbka, Jan (referee) ; Fuis, Vladimír (advisor)
Master thesis is focused on the research of influence of selected substantial parameters on stress – strain states in the deep groove radial ball bearing. The influence of radial load is analyzed, such as the influence of size of the bearing and row of the bearing, also influence of radial clearance is quantified. Next, the influence of thermal distribution in the bearing is analyzed for different combinations of thermal distributions and radial clearances. Conclusions from analyses are then used in the last task – suggestion of radial clearance for customer – specified assembly. Problem is solved using the finite element method (FEM) in pre/post processor MSC.Patran and solver MSC.Marc. To make analyses faster the substantial parameters are implemented in the algorithm for automatic generation of the bearing calculation (batch file).The theme of this thesis was commissioned by ZKL - Research and development, a. s.
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Analysis of residual stresses in arterial wall
Novák, Kamil ; Fuis, Vladimír (referee) ; Burša, Jiří (advisor)
This thesis deals with computational modeling of the influence of residual stresses in idealized geometry of blood vessels and subsequent application of acquired knowledge to abdominal aortic aneurysm. In the terms of quality of the computational model, we reduced the uncertainties that are included in the computational model without considering the influence of residual stresses. The basic assumption of homogenization significant peaks of the stress between inner and outer vessel wall was met for each level of the computational model Methods that have been used are: deformation method (opening angle method), inverse mechanics of large deformations, fictitious temperature – for linear elastic material and hyperelastic material defined by the constitutive model. Numerical verification was carried out using program ANSYS.
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Stress-strain analysis of real contact surfaces
Chrenko, Peter ; Fuis, Vladimír (referee) ; Návrat, Tomáš (advisor)
Currently, the wear of the articulating surfaces in contact have a significant influence on the life of hip joint replacement. It is therefore desirable to determine the influence of certain aspects on the wear of replacement. For this reason, master´s thesis deals with the influence of asperities of real surfaces of the hip joint replacement on its wear. The aim is to create computational models that would correspond to the real surface of the scanned prosthesis, performing strain- stress analysis and comparison with the results without the presence of asperities.
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Analysing of the design of the opening mechanism for the floor hatch
Metelka, Jiří ; Houfek, Martin (referee) ; Fuis, Vladimír (advisor)
In a family house not far from Brno, there is an entryway hole for getting into the space under the floor. The hole is covered by a high weight concrete hatch. For easier manipulation with the hatch an opening mechanism was designed and manufactured. This mechanism had been installed under the hatch and nowadays it works well. This master’s thesis deals with description of main components of the mechanism and their function. Load analysis and stress-strain analysis are the major part of this thesis. At the end of this work the analysis results are commented and some suggestions for further research are proposed.
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Application of tensegrity structures in modelling of mechanical behaviour of smooth muscle cells
Bauer, David ; Fuis, Vladimír (referee) ; Burša, Jiří (advisor)
The master’s thesis deals with the computational modelling of the mechanical testing of isolated smooth muscle cells. The main aims are to create computational model of a cell, to simulate single-axis tensile test and to modify the model so that the model reflects real mechanical response. The model of the cell includes cytoplasm, nucleus, cell membrane and cytoskeleton which is modelled as a tensegrite structure. On this model the tensile test was simulated in case of the cell with cytoskeleton and the cell with distributed the cytoskeleton. Force-elongation curves, which were obtained from this simulation, were compared with experimental data which were taken from literature. Tensile properties were measured on freshly isolated cells from rat thoracic aorta, cultured cells, and cells treated with cytochalasin D to disrupt their actin filaments. It was found that the cytoskeleton influence on the cell load in computational model was smaller than in the real cell. Therefore the model was modified by changing material propreties and geometry so that the model of the cell corresponded with the different types of experimentally measured cells.
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Evaluation of elastic parameters for models of isolated cells
Krbálek, Jaroslav ; Fuis, Vladimír (referee) ; Burša, Jiří (advisor)
This diploma thesis focuses on computational modeling of the cell mechanical tests. The goal of this thesis is to build a cell model and to simulate compression test on this model. If necessary, the model should be adjusted so the model reflects real cell behavior. It was created the cell model reflecting cytoplasm, nucleus, membrane and cell cytoskeleton. Cytoskeleton was modeled as tensegrity structure. After this, the pressure test was simulated on this model. The behavior of the cell model and real cell was compared using the stress force. The stress force - cell deformation curve was markedly different for the cell model and the real cell. For this reason, the cytoplasm material model was adjusted. The difference between the curves was acceptable after this modification. It was found during computations that the cytoskeleton model influence on the cell load is minimal. These results does not reflects real cell behavior, which means that the model is considered inadequate for performing stress load simulation.
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Stress-strain analysis of lower limb prosthetic
Musilová, Kateřina ; Fuis, Vladimír (referee) ; Návrat, Tomáš (advisor)
This master thesis deals with lower-limb prosthesis. The aim of the first part of this work is stress-strain analysis of trans-tibial prosthesis, which is understand without prosthetic socket and the foam prosthetic feet. Analysis is made using finite element method in ANSYS Workbench 12.0 software. For the purpose of setting up the computational model it is necessary to make few partial models. Model of geometry of the prosthesis is made in SolidWorks 2009. Based on the outputs of stress-strain analysis and the results evaluation, the critical component is chosen and this one is evaluated according to limite state for fatigue. The algorithm of evaluation of named component in the state of high cycle fatigue is discussed in the second part of this thesis.
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Strain stress analysis of BS splint
Řehák, Kamil ; Fuis, Vladimír (referee) ; Florian, Zdeněk (advisor)
This master‘s thesis deals with strain-stress analysis of hip joint together with the final applied total endoprosthesis with Burch-Schneider cage. The main point of my work was to find the solution of stress–strain analysis state, which has been mentioned before in connection with Burch-Schneider cage. I describe the technique of geometric creation of whole body system, component´s materials or conditions which are neccessary for calculation. In coclusion there are results achieved in variants. In the first option the case of bone tissue was considered, which don’t reach degradation mechanical properties effect straining under Burch-Schneider cage. In some cases when the bone tissue is untimely forced, the necrosis of bone tissue takes place under Burch-Schneider cage. This possibility is described in the second option of type. For every option there was a case which was calculated with applied screw or without it. In all option mechanical features of cancellous bone tissue and their change influence on achieved results were considered. This problem was solved computational simulation in commercial software Ansys Workbench 12.0.
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Reliability analysis of the hip joint endoprosthesis ceramic head
Málek, Michal ; Janíček, Přemysl (referee) ; Fuis, Vladimír (advisor)
This diploma thesis deals with probability of fracture ceramic head of total hip endoprosthesis during tests by the standard ISO 7206-5. In the first part is made stress analysis with method of finite elements in program ANSYS. Six types of ceramic head with different geometry was analysed for ideal geometry of head and shaft, and also for shape imperfections from nominal conical shaft and head. The final values of principal stress from stress analysis were entry values for the second part – probability of fracture analysis. Weibull weakest-link theory was applied, namely 3-Parameter and 2-Parameter Weibull distribution.
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Design of oil tank for SST 300 turbine
Janoštík, Milan ; Fuis, Vladimír (referee) ; Krejsa, Jiří (advisor)
Thesis deals with oil-turbine frame of the model SST 300 SST 400. This work is divided into several parts. Beginning of this thesis deals with a description of the problem and the oil economy. Next part is concerned with 3D design model of the oil tank in the program ProEngineer Wildfire 2.0. Final part describes a creation of manufacturing drawings with BOMs. In conclusion, the thesis presents the results of additional topics, such as a computational model in Ansys 11 and making the calculation of tension or bonds in an oil suspension in the frame. The result of this work is the full-fledged design of the weldment of oil frame, which was submitted for approval to the Siemens Company, which will continue in the subproject tasks of new turbo model SST 300 pattern SST 400.
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