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Comparison of frictional properties of cosmetic massage products
Dohnal, Petr ; Čípek, Pavel (referee) ; Vrbka, Martin (advisor)
This bachelor’s thesis examines tribological properties of massage products (creams and oils). Its aim is to create a comparison of the selected products. Tribometer in the pin-on-plate configuration was used for the experiment because of its ability to simulate the process of rubbing the product on the skin. Cowhide was used as a model of human skin. The attributes of products were compared based on the characteristics of the coefficient of friction during the measurements. Through the experiments a suitable parameter was found for easy comparison of the product's durability. According to the results the best oil was selected in terms of durability and lubrication. The thesis could be used as a basis for creating a standardised method for evaluation and selection of products suitable for massage purposes.
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Design of a belt grinder for robotic grinding
Šimara, Vít ; Vetiška, Jan (referee) ; Pavlík, Jan (advisor)
This bachelor thesis focuses on stationary robotic belt grinder. The grinder is designed to be tiltable in multiple axes, to guarantee its versatility. The theoretical part describes the belt grinder’s working principle and the fundamentals of robotic grinding. In addition, current trends in this branch are described. At the beginning of the practical part, the concept of the grinder is configured, part by part. This configuration is based on the theoretical research and the choice of the best option. The mechanical design follows, supported by calculations, indispensable to ensure the right functionality of the machine. This thesis’s outlet is a 3D model of the mechanical construction of the grinder with a partial drawing and technical documentation.
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Influence of surface microstructure on implant lubrication processes in contact
Matovič, Martin ; Odehnal, Lukáš (referee) ; Ranuša, Matúš (advisor)
This bachelor thesis deals with the lubrication of microstructured prostheses of the first metatarsophalangeal joint. The aim of the research is the service life of joint replacements by creating a microstructure on the surface of the material. The work focuses on the influence of microstructures on lubrication processes in contact and coefficient of friction. Fluorescence microscopy in combination with a reciprocating tribometer with the possibility of recording frictional and loaded forces was used to observe the contact area. The number and average particle size of albumin, which plays an important role in contact lubrication, were then examined to record the camera. The testing was performed on two material combinations, namely CoCrMo - Glass B270 (hard pair) and CoCrMo - PMMA (soft pair), which were only four different microstructures. Elsewhere, the influence of microstructures on lubrication processes in contact for hard and soft pairs is indicated, which can be used to design further measurements.
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Friction analysis of hip joint replacements with coated surface
Nosek, Matěj ; Streďanská, Alexandra (referee) ; Nečas, David (advisor)
This bachelor thesis focuses on the effect that results from applying a coating to hip joint replacement based on the friction coefficient. The aim of this thesis was to conclude a comparison between individual combinations with and without coating in three types of fluids. Experimental measurements were conducted in configuration ball-on-head in a pendulum hip joint simulator. For these measurements, DEWEsoft, MATLAB, and MS Excel were used. During the measurements, four balls, two cups, and three fluids were used. The coating is a polymer-based solution made out of PEGMA-360 a PEGDMA-550. With the usage of the coating, gathered results point out that the coefficient of friction declines by a maximum of 5,4 % and increases by a maximum of 16,1 % compared to those without any coating. Results presented by this thesis may be in the service of further research of coatings and their application on hip joint replacement, which might increase the potency of those implants.
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Conceptual design of a polymeric gear tester in vacuum
Ptáček, Matyáš ; Šperka, Petr (referee) ; Černohlávek, Mikuláš (advisor)
The bachelor thesis deals with the conceptual design of a polymeric gear tester in vacuum. Using a test device, it is possible to test the coefficient of friction in gears. At the beginning of the work is described the issue of operating conditions of satellites in low orbit together with the effects that affect them. Subsequently, suitable polymeric materials are selected, and current publicly available test rigs are described. Based on the research, two conceptual designs are made, one of them is selected and described in detail at the end of the work.
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Software for Determination of Aerodynamic Losses
Ondrák, Adam ; Skála, Zdeněk (referee) ; Lisý, Martin (advisor)
This work deals with the creation of a program for calculating the tensile losses of an in-dustrial boiler. The work is divided into four parts. The first part of the thesis deals with a theoretical introduction to the issue of pressure losses. The second part deals with all equations and procedures by which the program was created, as well as the limitations and conditions of using a given type of equation. The third part consists of a sample calculation of pressure loss-es of a real boiler. Furthermore, in the third part, the correctness of the program function is checked, where the measured losses on the real device were compared with the losses calcu-lated by the program. The fourth part deals with the influence of the boiler's parameters on its pressure losses, where the individual losses were graphically represented and compared to determine the sensitivity analysis. The output of this work is a functional program that has been optimized for ease of use and requires almost no knowledge of the user.
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Design of a simulator module for analysis of friction and wear of teeth during cleaning
Snopek, Lukáš ; Streďanská, Alexandra (referee) ; Vrbka, Martin (advisor)
This thesis focuses on the design of a module for the tribological simulator Bruker UMT TriboLab, which will be used in research in the field of analysis of wear of hard dental tissues and filling materials due to tooth cleaning. The aim of this work was the design of experimental conditions, module construction, creation of drawing documentation, production and subsequent implementation of a validation experiment. The conditions of the experiment were determined on the basis of research and to create an optimal design solution, prototypes were continuously produced using the 3D printing method. Finally, two toothbrush fixtures and two dental filling sample fixtures were made based on the drawing documentation. Subsequent assembly of the fixtures and the implementation of the experiment on the tribometer verified their functionality, which makes it possible to declare all the goals successfully met. Now these fixtures will be part of several research tasks in the field of oral biotribology.
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Biotribology of artificial tears for the treatment of dry eye syndrome
Černohlávek, Mikuláš ; Daniel, Matej (referee) ; Vrbka, Martin (advisor)
This master thesis is a part of the project TAČR TREND, which aim is the development of new ingredient for treatment of dry eye syndrome. Developed ingredient is derivative of hyaluronic acid, which is in this thesis compared with native hyaluronic acids and commercial eye drops. Aim of this thesis is to describe rheological and tribological properties of measured samples in terms of viscosity, mucoadhesivity and coefficient of friction. Coefficient of friction was measured on created tribological model of the eye in pin-on-plate configuration which represents physiologically relevant sliding speeds of blinking. Comparison with native hyaluronic acids and commercial products of eye drops showed, that derivative reaches higher values of viscosity, has mucoahesive properties and has low values of coefficient of friction. Those key parameters show that modification of hyaluronic acid is promising way for drug development for dry eye disease.
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Friction of compliant contacts
Vala, Martin ; Galas, Radovan (referee) ; Nečas, David (advisor)
This bachelor’s thesis deals with the study of the friction of compliant contacts and parameters affecting it. First section of this thesis provides analysis of current problematics with friction and compliant materials. In the next section basic definition of friction, compliant material and compliant contacts is provided with an actual study of up-to-date articles. Last section of this thesis is discussion dealing with all the articles and pointing out the influencing parameters. Followed by potential research pathways.
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Development of the coefficient of friction and lubrication film in a total knee replacement during a gait cycle
Odehnal, Lukáš ; Horák, Zdeněk (referee) ; Ranuša, Matúš (advisor)
This master´s thesis deals with the experimental analysis of the coefficient of friction and lubrication film in total knee replacement. The experiments are performed on a knee joint simulator, with an implemented module for measuring friction. To observe film formation, fluorescent microscopy is used. The experiments are mainly focused on a detailed description of the influence of parameters occurring during the gait cycle. This approach should significantly help in describing the tribological processes that occur in the total knee replacement. The results confirm previous investigations in terms of axial load, where the coefficient of friction decreases with the increasing load. In the case of lubrication film, no significant changes are observed. On the contrary, while investigating the influence of SRR, noticeable changes in film formation are observed while the coefficient of friction being unaffected. While describing the whole gait cycle, precise results are obtained only in the first half of the cycle as the second half is accompanied by the occurrence of large deviations from a rapid decrease of load. This work provides a better understanding of the field of lubrication film in total knee replacements. Moreover, thanks to the simultaneous measurement of the coefficient of friction and the observation of the contact area, it is possible to draw better conclusions than if the experiments had been carried out separately.
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