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Influence of Structure Directionality on Fatigue Properties of Formed Al Alloy.
Jíša, David ; Mazal, Pavel (referee) ; Liškutín, Petr (advisor)
The main goal of this diploma thesis is the examination of the influence of structure directionality on fatigue properties of formed aluminium alloy 6082/T6. The main attention is focused on the study of the influence of structure directionality on kinetics of short fatigue cracks growth. The measurement of short fatigue cracks growth was performed on cylindrical samples. The samples were made in two different directions; one parallel with the forming direction and second perpendicular to the forming direction. Servo hydraulic machine MTS 880 was used for the cyclic loading. The samples were cycled at two different constant stress amplitudes. Cyclic loading was systematically interrupted in order to measure the length of short cracks by a light microscope. Tensile tests, measuring of cycling hardening-softening curves, observation of microstructure, observation of surface relief, measuring of microhardness and fractographical analysis of fracture surfaces were used for further examination of the influence of the structure directionality. Some of these measured characteristics did not show any influence of the structure directionality (microhardness, fatigue life curve, Young modulus). In other cases is this influence measurable, however insignificant (yield stress, ultimate stress, cyclic hardening-softening curves and kinetics of short fatigue cracks growth). It can be summarised that the material, though the directionality of its microstructure is apparent, shows relatively isotropic mechanical behaviour.
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Modification of clamping part of the test machine RUMUL Cracktronic 160
Beran, Pavel ; Hutař, Pavel (referee) ; Mazal, Pavel (advisor)
This diploma thesis deals with the structural design of the chucking jaws for RUMUL Cracktronic 160 testing machine. This apparatus is used in the fatigue laboratory of Institute of Machine Design FME BUT. Simplification, speed improvement and better test sample griping are expected gains of the new clamping system. Solidworks system is used to create 3D model of the jaws. Stress analysis is created by Finite element method in ANSYS Workbench software.
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Reversing cross for flexo printing machine
Falta, Jan ; Mazal, Pavel (referee) ; Brandejs, Jan (advisor)
The aim of this work is to develop a new concept of the reversing cross for flexo printing machine SomaFlex Optima. Work includes a description of the machine, the basic description of the principle of flexography. There is explained the principle of turning the material, the current method of supplying air to the air cushion and the difference between the blower and compressor as an air source for the air cushion. Conceptual solution includes two variants, namely vertical and horizontal position of turning bars. For each alternative are described its advantages and disadvantages.
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Scanning of acoustic emission signal by using waveguides
Bančák, Matej ; Vlašic, František (referee) ; Mazal, Pavel (advisor)
Bachelor thesis is focused on the issue of scanning acoustic emissions from the surface of solid body and scanning with the help of acoustic waveguide placed on the solid body. The work includes the review of the present ways of scanning acoustic emissions, options of installation waveguide and propagation of waves. The practical part is focused on the experiment, which compares measured values from the surface of the test body and from the waveguide. The measurement was realized on steel of the standard quality for using a measuring instrument Dakel Xedo. The next object of this work was try to attenuate the reflected signal, which is produced by the action of force on the test body.
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Raking equipment of sedimentation tank
Šebela, Michal ; Mazal, Pavel (referee) ; Brandejs, Jan (advisor)
Bachelor's thesis contains summary of systems for raking equipment of sedimentation tank. It deals with a specific design solution raking device installed in sewage treatment plant in Ostrava. The goal of this thesis is design suitable solution of raking device. Thesis also contains drawing documentation.
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Ramps and other devices for the entrance of handicapped to the buses
Pavlo, Matej ; Nohál, Libor (referee) ; Mazal, Pavel (advisor)
The bachelor work brings the critical assessment of the construction solutions of the aids for boarding of the physically handicapped persons in the busses of the municipal mass transportation and at the same time it deals with design of some tipping ramp variants, which try to improve the faults of the present ramps. The first part contains the review of the present situation of the aids for boarding and entrance of the physically handicapped persons. The second part contains the designs of the construction solutions, which could be of use in the busses of the municipal mass transportation. And in the last part are these designs reviewed and compared each other.
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Identification of changes in surface texture of the selected materials by the method of acoustic emission
Eliáš, Jan ; Bumbálek, Bohumil (referee) ; Mazal, Pavel (advisor)
This Bachelor thesis deals with monitoring changes in surface roughness of moving metal objects rubbing each other on selected parameters of acoustic emissions. Parameters of the AE signal during the movement of bronze and cast iron bodies on the surface of a fixed steel rod were measured, recorded and analyzed. These results can serve for further research on assessment possibilites of the degree of wear of a surface using the AE method. Measuring was performed using a measuring product intended for AE and the Dakel sensors and measuring software.
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Transmission of Linear Pneumatic Cylinder
Bedeč, Csaba ; Mazal, Pavel (referee) ; Nevrlý, Josef (advisor)
The main subject of this bachelor's thesis is analysis and design of a mechanism for converting linear motion to rotary swinging motion used as door drive in the buses. The first part contains analysis and application of the applicable types of mechanisms. The work contains analysis and design of a cam-type mechanism in the second part. The analysis of the designed variants and selection of optimal parameters of the proposed mechanism is the last part.
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