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Design of DH bike fork with magnetorheological damper
Salva, Matúš ; Robenek, Dětřich (referee) ; Strecker, Zbyněk (advisor)
When mountain biking over rough terrain, comfort and sufficient wheel pressure are often the limiting factors. That's why there is an effort to innovate suspension and develop dampers that provide better damping characteristics. The usage of semi-active suspension is one way to achieve the desired improvement over the currently used passive systems. In this work, the aim was to develop a magnetorheological damper that is suitable for implementation in commonly available mountain bike forks and whose damping characteristics allow the use of the Skyhook algorithm. A functional model of an MR damper with a stroke of 240 mm and an outer diameter of 29.5 mm, whose dynamic range is 9.5 at a piston velocity of 0.25 ms-1 and a time response of 17 ms, was developed. The magnetic circuit of the manufactured functional pattern is of 11SMn30. The damper served to verify the functionality of the concept and at the same time its damping characteristics were experimentally verified and compared with the predicted values. Due to the combination of numerical and analytical model, a very good agreement between prediction and experiment was achieved. Hence, an MR damper with a magnetic circuit made of Hiperco/Vacoflux 50 material was subsequently designed with a predicted dynamic range of 9.5 and a time response of less than 10 ms. The resulting total weight of the design is 0.68 kg. This design fully satisfies all requirements. When used in combination with semi-active control using the Skyhook algorithm, it is predicted to improve ride comfort by 28 %. The potential to use the proposed MR damper is with the increasingly widespread electric bicycles mainly due to the higher weight in conjunction. At the same time, however, the possibility of using it on a regular bicycle is not excluded. Semi-active suspension is a new and not yet widely used technology in cycling and has the potential to reach a new range of consumers. Considering all the advantages and disadvantages, it can be concluded that the proposed MR shock absorber allows to improve the rideability of mountain bikes both in terms of ride comfort, wheel traction or in the form of reduced energy expenditure during pedalling due to energy absorption by the suspension.
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Design of semiactive suspension for mountain terrain bike
Mráz, Kryštof ; Kubík, Michal (referee) ; Strecker, Zbyněk (advisor)
This Bachelor Thesis is focused to design semiactive suspension of mountain bike using MR damper. In research part of thesis is summarised knowledge about passive and semiactive suspension of mountain bikes and about MR dampers. Behaviour of suspended front fork was simulated using virtual dynamic model which was created in graphic environment MATLAB Simulink. Semiactive algorithms Skyhook and modified Groundhook and for comparison also passive settings are simulated. According to results of these simulations is designed semiactive suspension with MR damper which has effect to stabilising contact force of front wheel and therefore increases safety of rider.
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The construction of MR damper for MTB fork suspension
Salva, Matúš ; Macháček, Ondřej (referee) ; Strecker, Zbyněk (advisor)
In MTB is front suspension very important part of bike. It ensures comfort of ride and security. This Bachelor thesis deals with the theoretical design of semi-active suspension for MTB fork. For this purpose of simulation models of suspension used adaptive damper and MR damper with Skyhook algorithm were made. Range of forces for MR damper for use in MTB was made on basis of simulation. Simulation results of semi-active suspension were compared to simulation results of adaptive suspension which contained F-v characteristics of damper used in downhill bike. MR damper with Skyhook had better results in field of riding comfort and it retained adhesion of adaptive damper. Final range of forces for MR damper in possible to use for more tests or for design of MR damper for fork of mountain bike.
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Engineering design of a fullsuspension mountain bike frame
Zvozil, Ondrej ; Lošák, Petr (referee) ; Březina, Lukáš (advisor)
The aim of this bachelor thesis is designing of a full-suspension mountain bike frame. At the beginning of the thesis mountain bikes are divided into categories, the function of a shock absorber is described and issues of bike kinematics and related characteristics are clarified. The thesis also describes properties of the most used materials for bike frames manufacturing. Subsequently, the most common systems of rear wheel linkage are analysed. Next, the requirements for own design are identified in terms of geometry, construction, kinematics and a creation of its 3D model in SolidWorks software. The characteristics of designed frame are analysed by specific software Linkage X3. Then a static analysis in Ansys software is made in order to select bearings for individual pivots. The final part of the thesis is dedicated to visualisation of designed frame.
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Design of mountain-bike crossbar and its FEM analysis
Jelínek, Martin ; Maňas, Pavel (referee) ; Vrbka, Martin (advisor)
The aim of this diploma thesis is the part of evolution of the new bicycle frame for mountain biking, category enduro. The first part of this thesis is focused on creating dimensional modified model of the bike frame in CAD system SolidWorks. Subsequently this frame will be detailed by FEM analysis in software ANSYS Workbench and determine boundary conditions for this analysis. The final part is about visualization of the new bike frame.
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Physiological response of a cyclist when using various components of a mountain bike.
Bížová, Michaela ; Brtník, Tomáš (advisor) ; Turčová, Ivana (referee)
Title: Physiological response of the cyclist's organism when using different mountain bike components. Objectives: The goal of this final thesis was to assess the different influence of bicycle components on the physiological response of the cyclists' organism using a systematic research. Methods: The main sources were searched in the scientific databases Taylor and Francis, Researchgate, ScienceDirect. In the included studies, individual researches were searched that were focused on the physiology of the body of the tested cyclists. These were experiments. These investigations investigated the overall performance using different cycling components. From the compared results of all researches, possible moderating factors of the influence of these components on the energy demand during driving were determined. Results:A total of 18 studies were used in this work, focusing on the physiological response of cyclists when using different components of a mountain bike and comparing somatic characteristics, including those of road cycling. Full-suspension mountain bikes provide greater comfort and shock absorption in off-road terrain, resulting in reduced physical exertion and energy demands during riding. Riding a bike with only front suspension was found to be more efficient and faster than using both...
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Pre-season training analysis of cross-country and maraton mountain bike racers
DOLEŽAL, Vladislav
Cílem této bakalářské práce byla kompletní analýza všech tréninkových procesů během předsezónní přípravy v celém přípravném období cyklistů a následně analýza závodních výsledků v cyklistické sezóně 2019/2020 u závodníků v kategorii junioři, juniorky a muži do 23 let. Hlavním cílem bylo zjištění, který trénink je nejefektivnější pro danou disciplínu cross country a maraton v těchto závodních kategoriích. Zkoumaný soubor tvořilo 6 lidí z Bike klubu Vimperk (závodního týmu Rouvy Specialized Racing). Součástí práce je také historické i novodobé pojetí těchto disciplín, ale i horského kola samotného a také studium odborné literatury a dalších odborných materiálů. Dále následovala syntéza, kdy po vyhodnocení zpracovaného materiálu a dat je výsledkem prohloubení poznatků o tréninku na horských kolech v těchto obou disciplínách a zároveň vytvoření a doporučení ideálního tréninku pro závodníky těchto věkových kategorií.
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Analysis of material equipment of elite MTBO competitors
Chaloupská, Barbora ; Brtník, Tomáš (advisor) ; Šafránek, Jiří (referee)
Title: Analysis of material equipment of elite MTBO competitors Objectives: The aim of this work is to analyse the material equipment of elite MTBO competitors. That means mainly mountain bikes and their components. The bachelor thesis describes which material equipment the elite MTBO competitors use and if there are any differences among them. Methods: The questionnaire method was used to obtain data regarding the research objective. The analysis was applied in the description of individual types of bikes and their components, which elite MTBO racers use. Results: The analysis identified the key components of the bikes used by elite MTBO racers. These are a carbon frame, hydraulic brakes and 29 inch wheel sizes that are used by almost all elite MTBO racers. Half of the competitors use full suspension bikes and half use hard-tail bikes with a suspension fork. Differences are in the less important components of the bike, which adapt to personal preferences. Conclusion: The analysis of the results showed the use of the same important components of the bike, but they highlighted personal preferences in less important parts. Nevertheless, the preference of the middle options is clear. Even if these options are represented as advantages and disadvantages. Keywords: MTBO, mountain bike, equipment, competition
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Design of DH bike fork with magnetorheological damper
Salva, Matúš ; Robenek, Dětřich (referee) ; Strecker, Zbyněk (advisor)
When mountain biking over rough terrain, comfort and sufficient wheel pressure are often the limiting factors. That's why there is an effort to innovate suspension and develop dampers that provide better damping characteristics. The usage of semi-active suspension is one way to achieve the desired improvement over the currently used passive systems. In this work, the aim was to develop a magnetorheological damper that is suitable for implementation in commonly available mountain bike forks and whose damping characteristics allow the use of the Skyhook algorithm. A functional model of an MR damper with a stroke of 240 mm and an outer diameter of 29.5 mm, whose dynamic range is 9.5 at a piston velocity of 0.25 ms-1 and a time response of 17 ms, was developed. The magnetic circuit of the manufactured functional pattern is of 11SMn30. The damper served to verify the functionality of the concept and at the same time its damping characteristics were experimentally verified and compared with the predicted values. Due to the combination of numerical and analytical model, a very good agreement between prediction and experiment was achieved. Hence, an MR damper with a magnetic circuit made of Hiperco/Vacoflux 50 material was subsequently designed with a predicted dynamic range of 9.5 and a time response of less than 10 ms. The resulting total weight of the design is 0.68 kg. This design fully satisfies all requirements. When used in combination with semi-active control using the Skyhook algorithm, it is predicted to improve ride comfort by 28 %. The potential to use the proposed MR damper is with the increasingly widespread electric bicycles mainly due to the higher weight in conjunction. At the same time, however, the possibility of using it on a regular bicycle is not excluded. Semi-active suspension is a new and not yet widely used technology in cycling and has the potential to reach a new range of consumers. Considering all the advantages and disadvantages, it can be concluded that the proposed MR shock absorber allows to improve the rideability of mountain bikes both in terms of ride comfort, wheel traction or in the form of reduced energy expenditure during pedalling due to energy absorption by the suspension.
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History of mountain biking in Vimperk- from 1989 to the present
Pomezný, Lukáš ; Kašpar, Ladislav (advisor) ; Kainová, Lucie (referee)
IN ENGLISH The work deals with the history of mountain bike in Vimpersko from 1989 to the present. Major cycling events, prominent racers, organizers and founders of a mountain bike section in Vimpersko should appear in the work. The main aim of this work is to investigate and record the arrival of a mountain bike in Vimpersko from 1989 to the present. Partial objectives include recording the main characters associated with the emergence of mountain bike races and a section in Vimperk and linking the topic with the history of cycling in the Czech Republic. The main method of work is the historical method enriched with interviews with the main actors of mountaine biking in Vimpersko.
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