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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
131

Vliv podstatných parametrů na velikost radiální vůle a deformačně napěťové stavy v kuličkovém ložisku / Influence of essential parameters on the radial clearance and stress-strain states in ball bearings

Šperka, Václav January 2014 (has links)
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.
132

Deformační a napěťová analýza vybraného páteřního fixátoru / Stress-strain Analysis of Chosen Spinal Fixation Device

Prášilová, Eva January 2014 (has links)
The degenerative and traumatic injuries of a spine are very frequent. In those cases it is necessary to stabilize the corresponding spine segment using a spine implant. The spinal implants are rigid or flexible, the latter known as dynamic ones in medical practice. In this thesis, the problems of the physiological spinal segment and the segment with implant were solved using the computational modelling (finite element method). Computational model consists of 4 lumbar vertebrae L2 – L5, intervertebral discs, joints and spinal implants. The spinal segment was loaded by the force 400N and 200N, than by force 200N together with bending moments 2,5Nm and 5Nm depending of the motion. The displacement of the whole system, contact pressure of cartilages, equivalent strain in cancellous bone and equivalent stress in the implant were analyzed. The deformation of the physiological model and the model with the implant are comparable, but the bone tissue of the model with the implant is dramatically more loaded in vicinity of the screws.
133

Využití metody konečných prvků pro modelování pohybu a napjatosti hlasivek při nastavování do fonačního postavení / Using finite element method for modelling of movement and stress of vocal folds during setting to phonation position

Šíbl, Michal January 2014 (has links)
This Master´s thesis deals with use of finite element method for modeling motion and stress of vocal folds during setting to phonation position. The thesis contains a description of the relevant anatomical structures and of the closely related formation of the human voice. A list of some previously published models of the function of human vocal folds follows. A part of my work was to create a model of geometry of the larynx using CATIA V5 and PTC Creo 2.0 on the basis of data acquired by MRI (magnetic resonance imaging). After that the model was converted into the calculation system Ansys Workbench 15.0 and, for solving contact problems, into Ansys Classic 15.0. To solve given problems, these programs use the finite element method (FEM). Solution was carried out for six different variants simulating individual motions of cartilages, corresponding to the activation of individual muscles. For each variant, the movements and stresses in the soft tissue of the vocal folds were evaluated. For variants with activation of IA, TA and LCA muscle it was also evaluated the contact pressure between the vocal folds. Finally, the thesis mentions the preparation of the model for the activation of the vocal folds movement by the muscles of the larynx.
134

Hluk a vibrace rootsových dmychadel / Noise and vibrations of roots blowers

Smrček, Martin January 2015 (has links)
This thesis is concerned with the spread of noise in the housing sets blowers, blower vibration, due to the shape of the geometry of the individual parts of the blower and the design of a suitable discharge muffler in order to achieve the highest possible attenuation. Analysis blower and silencer discharge was conducted using the finite element simulation ANSYS 15.0
135

Středové kloubové uložení lesního vyvážecího stroje LVS511 / Central joint of forest forwarder LVS 511

Horký, David January 2015 (has links)
This diploma thesis deals with stress analysis central joint of forest forwarder LVS 511. Stress analysis has been performed by finite element method (FEM) using the program NX I-deas. The diploma thesis was conducted in cooperation with the firm Strojírna novotný s.r.o.
136

Optimalizace stavebních konstrukcí s pravděpodobnostními omezeními / Optimization of building constructions with probability constraints

Kokrda, Lukáš January 2015 (has links)
The diploma thesis deals with penalty approach to stochastic optimization with chance constraints which are applied to structural mechanics. The problem of optimal design of beam dimensions is modeled and solved. The uncertainty is involved in the form of random load. The corresponding mathematical model contains a condition in the form of ordinary differencial equation that is solved by finite element method. The probability condition is approximated by several types of penalty functions. The results are obtained by computations in the MATLAB software.
137

Biomechanická studie fixátorů aplikovaných na tibii / BIOMECHANICAL STUDY OF EXTERNAL FIXATORS APPLIED TO TIBIA

Mrázek, Michal Unknown Date (has links)
External fixators are used in a treatment of complicated fractures and their properties have a crucial impact on treatment quality. Therefore, this thesis is concerned with a biomechanical study of a bone (tibia) with applied external fixators via strain-stress analysis and their comparison with a state of tibia without applied fixator (physiological state). After creating the volume models of geometry of tibia and seven variants of external axial fixators, the corresponding finite element method (FEM) models are created. The analysis of tibia without applied fixator and tibia with all studied fixators is made for three states of load which correspond to characteristic load states during the first stage of treatment. The strain-stress analysis is made using finite element method. Furthermore, the methods of displacement and rotation evaluation during loading are proposed. One can conclude from the results of the strain-stress analysis how the different variants of fixators prevent the displacement and rotation of the bone during the different load states and the comparisons with the physiological state of bone are made. Bone tissue loading is determined from the distribution and the values of the first and the third principal stresses. Finally, comparing the results of all variants the influence of the fixator length, the gap between the fixation elements near the fracture, the number and the setting of the fixation elements on the fixation properties is analysed.
138

Napěťově deformační analýza přírubového spoje / Stress and deformation analyses of the flange connection

Lehnert, Ondřej January 2016 (has links)
This master thesis deals with analytical calculation of the various flange connections using theory of thin-walled bodies and axisymmetric assumptions. The calculation is demonstrated by one specific geometry configuration. Numerical finite element method was performed to verify analytical calculation model and also this method enabled more in-depth analysis of the prying effect which has negative influence on the bolt connection tensile load. Output from this analysis is prying point location function in plate thickness dependence and application this function into analytical calculation.
139

Parametrická studie absorpčního prvku zadní části vozidla / Parametric study of the absorption element of the rear part of the vehicle

Vražina, Lukáš January 2016 (has links)
In 1995 was published a regulation from RCAR company which determines rules for crash tests in maximum speed of 15 km/h on vehicles lighter than 2,5 ton. The main reason was to reduce costs for car reparation in case of crash in low speed. My diploma thesis is focused on the modifications of deformation part in the car alias absorption part of the vehicle. In the first part of my diploma thesis has been done a research about organisations doing basic car crashes as well as topic focused on nonlinear mechanics and description of explicit FEM. In the second part of my work are settled conditions for crash simulation of a barrier into the car. There is an evaluation of critical force on the stringer. Afterwards the calculating simulation simplified on loading of absorption part and there are some material and form adjustments. In the final part of my diploma thesis is done a result comparison and development of the absorption part.
140

Analýza návrhu šroubového přípoje otočné desky kolesového skládkového stroje / Analysis of the design of the bolted connection pivot plate-wheel of bucket wheel stacker-reclaimerLoader

Šrajer, Jan January 2016 (has links)
This thesis describes an analysis of the design of the bolted connection pivot plate-wheel of bucket wheel stacker-reclaimer loader. The challenge solution is to decide whether the current design is suitable. The thesis contains comparison of calculation according to VDI regulation with the ČSN, performing stress analysis using FEM calculation model and a design of changes, joint bearings with steel structures.

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