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Influence of surface modifications on fatigue life
Gerec, Matúš ; Kučera, Pavel (referee) ; Vopařil, Jan (advisor)
This bachelor thesis presents the description of surface treatment technologies used on dynamically loaded mechanical parts. It explains the influence of each surface treatment on high–cycle fatigue life. Then the thesis describes the analytical calculation of fatigue limit of real part and approach to design of mechanical part on infinite life.
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Influence of glass fiber degradation on the mechanical response of a polymer composite
Součková, Lenka ; Knob, Antonín (referee) ; Čech, Vladimír (advisor)
The bachelor thesis studies the effect of fiber degradation with commercial sizing on the flexural properties of polymer composite based on unsaturated polyester resin reinforced with long unidirectionally oriented glass fibers. Fibres of age 23, 61, 67, 112 and 135 months were used to prepare a series of composite samples. The mechanical properties of a composite containing 40.5% % vol of fiber were determined using a three-point bending test defined by ASTM D790-17 standard. From the obtained data, the flexural strength, the flexural modulus and the flexural strain were evaluated. It has been found that the degradation of the fibers and their sizing leads to a reduction in flexural strength. This was due to the reduction of adhesion between the fibers and the matrix, thus also the quality of the interface, which caused insufficient stress transfer from the matrix to the fibre. The resulting difference in strength of composites with fibers aged 23 and 135 months was 0,19 GPa with respect to the origin value of 1,17 GPa. The obtained values were used to assess the correlation between the flexural strength of the composite and the shear strength. Pearson's correlation coefficient set at 0,71 corresponds to a strong correlation. The effect of fiber degradation on the flexural modulus has not been demonstrated.
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Manufacturing possibilities of modular cabinet
Valčík, Martin ; Řiháček, Jan (referee) ; Podaný, Kamil (advisor)
Bachelor's dissertation in subject Mechanical Engineering is focused on suggestion and evaluation suitable of technologies which are used for production of modular cabinet determined for switchboard cabinets STX, serial marking IP55/IK09 produced by company TVD - Technická výroba, Inc.. Technologies used for production are punching, cutting by laser or plasma beam, bending, welding MAG/MIG, WIG and spot welding. Surface finish is done by powder painting, zinc plating or anodization. In point of economical and quality view as the best procedure was choosed punching, bending, welding by MAG technology and powder painting.
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The technology of hot-dip galvanizing
Pometlo, Stanislav ; Osička, Karel (referee) ; Mouralová, Kateřina (advisor)
This thesis deals with the technology of hot-dip galvanizing. At the beginning of this work views into the history of hot-dip galvanizing and analysis of known technologies about applying of melted zinc into the surface of material. It further describes modification for surface before application of zinc´s coating. In the next part of the work are summarized the most common corrosions of hot-dip galvanized material. The work follows up the difficultness of operation for hot-dip galvanizing device. At the end of work describes cooperation with Alka Holding s. r. o.
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Monitoring of Solder Spreading Velocity on Metal Surface
Růžička, Miroslav ; Dušek,, Karel (referee) ; Starý, Jiří (advisor)
This work deals with flushing monitoring of spreading velocity on solder finishes Niau, OSP, Sn deposited on copper plated base material FR4 using digital cameras. After the reflow process is measured by length of spreading solder and size of wetting angle. It evaluates and compares the time dependence of velocity of spreading solder, length of solder spreading and wetting angle for NiAu, OSP, Sn finishes at different temperatures reflow and surface treatment.
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Targeted Preparation of Composite Based on PP with Inorganic Micro-, or Nanofiller with Different Adhesive Interlayer
Dombková, Julie ; Krčma, František (referee) ; Nezbedová, Eva (advisor)
The diploma thesis studies composite of PP and filler particle. As a particle filler was used commercially available CaCO3 (SOCAL 31). The submitted thesis had a goal to find new approaches and technologies of filler surface treatment in order to improve properties of composite materials. The plasma discharge behind static pressure was used for the surface treatment of the fillers. These fillers were afterwards analyzed by using of sedimentation analysis, turbidimetry, infra-red spectroscopy (FT-IR), X-ray diffraction analysis (XRD), scan electron microscopy (SEM), transmission electron microscopy and particle size distribution by laser diffraction. The composites with various volume parts of the fillers were prepared in PIB and studied by short-time tests. Furthermore, the influence of an adhesive layer on fracture mechanical properties of prepared composite was study. Regarding to experimental demand, there was not possible to realize long-term mechanical properties.
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Thermomechanical Stress of Lead Free Solder Joint
Libich, Jiří ; Šandera, Josef (referee) ; Starý, Jiří (advisor)
This diploma thesis deals with the reliability of lead-free solder joints at a different interconnection structures. The first goal is to design the test cases shape BGA (FC) for testing the strength of lead-free solder joints at shear test in link with design of measuring method to detection shear strength during isothermal aging of lead-free solder joints. Following this shear stressing is investigating influence material and process compatibility, ie. pads finishing, material of solder and integrate of temperature (this mean thermal energy supplied during soldering) to lead-free solder joint strength.
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Bonding in the automotive industry
Krejčí, Adam ; Hanáčková, Pavla (referee) ; Kubíček, Jaroslav (advisor)
The thesis presents a literature study of adhesive bonding technology. The work deals with the advantages and disadvantages of adhesive bonding, design of adhesive joints, technological processes of adhesive bonding and the division of adhesives. The thesis also discusses various materials used for the construction of car bodywork and their properties. The main focus of the work is on the use of adhesive bonding in the car industry, comparing traditional and modern technology used for the construction of bus bodywork. In the experimental part of the thesis, the aim is to reveal the influence of surface treatment on the resulting shear strength when employing metal to metal bonding.
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Influence of adhesive layer on the mechanical behavior of PP+ inorganic filler composite.
Švestková, Dana ; Krčma, František (referee) ; Nezbedová, Eva (advisor)
The diploma thesis was dealt with the study of system PP and particular filler, specifically PPH and like a filler was used commercially available CaCO3 (SOCAL P3). This type of filler is declared by the producer as a filler without surface treatment. The submitted thesis had a goal to find and testing the suitable method and methodology for defined surface treatment of the filler. This is the first step for systematic study of influence the various types of adhesive layer on mechanical properties of declared composite. The plasma discharge behind static pressure was used for the surface treatment of the fillers. These fillers were afterwards analyzed by using of sedimentation analysis, infra - red spectroscopy (FT-IR) and scan electron microscopy (SEM). The composites with various volume part of the fillers were prepared in PIB and studied by short-time tests. Regarding to experimental demand there wasn't possible to realize the whole originally intended program i. e. study of influence the different types of adhesive layer, including to form the model for FEM approach. Nevertheless finding and testing the suitable method of surface treatment is completely basic for the others study. The above mentioned method was used in this application for the first time and it is possible to consider this process like an original approach.
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