|
|
Parametric computational model of non-food bulk materials silo
Červený, Vojtěch ; Kvarda, Daniel (referee) ; Maňas, Pavel (advisor)
This bachelor thesis deals with the creation of a parametric computational model of a bulk material silo. The work includes acquaintance with the issue of bulk materials, the theory of calculation of pressure conditions in silo, introduction of the proposed structure, creation of a parametric geometric model in the CAD system and the calculation model in the FEM system. The thesis includes a brief introduction to the software used and the principle of working with the created models.
|
|
|
Experimental investigation and numerical modelling of top of rail products
Kvarda, Daniel ; prof.Roger Lewis (referee) ; Meierhofer, Alexander (referee) ; Hartl, Martin (advisor)
Tato disertační práce se zabývá experimentálním a numerickým studiem maziv pro temeno kolejnice. Tyto maziva se používají ke snížení opotřebení, hluku a zlepšení energetické účinnosti kontaktu kola a kolejnice. V posledních dvou desetiletích byl proveden rozsáhlý experimentální výzkum týkající se použití maziv pro temeno kolejnice. Avšak velmi málo výzkumu bylo zaměřeno na základní mechanismy těchto produktů, zejména na problémy s nízkou adhezí. Aplikace matematických modelů v této oblasti také nebyla dosud zkoumána. Cílem této práce je pomocí matematického modelu vysvětlit třecí chování a problémy s nízkou adhezí maziv pro temeno kolejnice. Model předpokládá jak tření vznikající interakcí nerovností pevných látek, tak separaci mazacím filmem. Validace tohoto modelu byla provedena na experimentálním tribometru se schopností měřit tloušťku filmu pro ověření přesné predikce separace povrchu. Komerční tribometr byl použit ke zkoumání vlivu jednotlivých složek v mazivu pro temeno kolejnice na bázi oleje. Sada reologických testů v kombinaci s modelem ukázala, že pevné částice měly velmi malý vliv na zvýšení adheze po aplikaci. Následně byly testovány různé typy maziv pro temeno kolejnice pomocí vysokotlakého torzního zařízení. Mezný režim tření těchto látek byl hodnocen představeným modelem. Bylo zjištěno, že pozitivní třecí vlastnosti, které by tyto produkty měly poskytovat, jsou výsledkem velké skluzové vzdálenosti, která mění složení třecí vrstvy. Nízký koeficient tření v důsledku nadměrné aplikace se vyskytl při stejném aplikovaném množství u všech testovaných látek. Tato diplomová práce představuje původní výzkum rozšiřující znalosti o produktech pro temeno kolejnice.
|
|
|
Design of device for material antiseizure testing
Burk, Filip ; Kvarda, Daniel (referee) ; Šperka, Petr (advisor)
Friction between materials can be partially eliminated by lubrication between surfaces. In order to select the correct lubricating oil, it is necessary to have the necessary test means to make an evaluation. One of these is a four-ball tester, which is lacking at the BUT Institute of Design. The aim of the bachelor thesis is the design of a modification of the existing tribometer R-MAT 3 for a four-ball configuration. The review part includes a description of the preparation, measurement and evaluation of the four-ball tester and an evaluation of conventional testers. The design of the ball mounting, drive and torque transfer to the tribometer spindle was carried out. Measurement and recording of friction torque, contact force and temperature during the test was also proposed. The result is a configuration ready for implementation. The review section includes a description of the preparation, measurement and evaluation of the four-ball test and an evaluation of conventional testers.
|
|
|
The modification of a field tribometer frame
Matějček, Ondřej ; Kvarda, Daniel (referee) ; Valena, Martin (advisor)
The main topic of this Bachelor thesis is a modification of a field tribometer frame. Firstly, the research of field tribometers measuring coefficient of adhesion on the real track was conducted. Next, the current state of the tribometer to be modified was analysed. Based on research and tribometer current state analysis the parameters of the design were determined. Followed by several conceptual variations of the frame and attachment mechanism. From these solutions, the best one was selected and processed into the final form. The results of this thesis are field tribometer frame with attachment mechanism. The Bachelor thesis also contains drawing documentation.
|
|
|
Rolling bearing stiffness
Krišpín, Jakub ; Kvarda, Daniel (referee) ; Košťál, David (advisor)
Given bachelor thesis deals with stiffness of model shaft configuration which is mounted overhung in two single row radial ball bearings. Initial part of the thesis is focused on roller bearings and parameters affecting their stiffness. Then a model assembly is designed. The stiffness calculation calculation of the assembly is performed by MESYS software. Subsequently, an experimental stiffness measurement is performed. Stiffness is determined by measuring the deformation of the shaft at given load. Values are compared with each other and the sensitive points in the calculation are determined. The results of the thesis mainly lead to determination of the magnitude of the influence of individual parameters on the change in stiffness. The functionality of the MESYS software was verified.
|
|
|
Parametric computational model of non-food bulk materials silo
Červený, Vojtěch ; Kvarda, Daniel (referee) ; Maňas, Pavel (advisor)
This bachelor thesis deals with the creation of a parametric computational model of a bulk material silo. The work includes acquaintance with the issue of bulk materials, the theory of calculation of pressure conditions in silo, introduction of the proposed structure, creation of a parametric geometric model in the CAD system and the calculation model in the FEM system. The thesis includes a brief introduction to the software used and the principle of working with the created models.
|
|
|
Top of rail lubricant development
Skurka, Šimon ; Polach, Pavel (referee) ; Kvarda, Daniel (advisor)
Friction modification within the wheel-rail interface is an important way of achieving ecologically friendly transportation of both persons and goods. This thesis aims to develop a new TOR lubricant, which will be able to maintain suitable frictional conditions while securing minimal adhesion required for traction. All measurements were carried out on tribometer MTM in the ball-on-disc configuration. In the first step, individual components were examined. More complex compositions were measured after that and the three best of them were compared with commercial TOR lubricants. The results show a good ability of developed compositions to maintain required adhesion, reduce wear, and all of them had resistivity against over-lubrication. Lastly, the process of lubricant verification before its application in real traffic was discussed.
|
|
|
Race car bonnet shape design based on flow analysis
Šnajdr, Petr ; Kvarda, Daniel (referee) ; Michalec, Michal (advisor)
The bachelor’s thesis deals with reducing aerodynamic drag of a pneumobile. The thesis summarizes knowledge in the field of vehicle aerodynamics and the principle of CFD simulations. The essence of the work is bonnet shape design of racing pneumobile Typhoon, developed at FME BUT, for lowest possible air resistance. CFD simulations are used to observe and analyse the influence of the bonnet shape on the aerodynamics properties. The designed shape solution of the bonnet significantly contributes to the reduction of aerodynamic drag compared to the existing bonnet. Thanks to this, the vehicle’s parameters are improved from maximum speed to the range. The acquired knowledge can also help in the further development of pneumobiles and in improving the setting of the computational model described in the work.
|
|
|
Conceptual design of device for application of anti-icing agents on overhead catenary
Rohánek, Tomáš ; Kvarda, Daniel (referee) ; Omasta, Milan (advisor)
This bachelor’s thesis deals with icing of overhead contact lines. Relevant patents and existing commercial systems for applying anti-icing agents are comprehensively described and evaluated in the thesis. Based on that, two new concepts for public transportation are proposed. Compared to the existing systems, these concepts bring improvement in operational parameters and expand the number of products offered at the market. Afterwards, both concepts are critically assessed.
|
|
|
Analysis of contaminants in wheel and rail contact
Straka, Tomáš ; Galas, Radovan (referee) ; Kvarda, Daniel (advisor)
Wheel/rail contact is significantly influenced by so called third body – contaminants. Aim of this bachelor’s thesis is to analyse those contaminants in the contact and to create a brief overview. Short introduction into problem of wheel/rail contact is included, followed by description of main contaminants occurring in the contact. This thesis may be used as introduction into contamination of wheel/rail contact problem.
|
guest ::
