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Vibration and Acoustic Emission Reduction of Powertrains using Virtual Engine
Svída, David ; Kovář, Rudolf (referee) ; Dundálek, Radim (referee) ; Kovář, Rudolf (referee) ; Dundálek, Radim (referee) ; Píštěk, Václav (advisor)
Doctoral thesis deals with combustion engine cranktrain vibrations and vibration analysis methods. The work applies new computational models aimed at powertrain vibration decrease. The computational models can be used in the first stages of powertrain development. Temperature dependences of the rubber shear modulus and loss factor characteristic are found by response analysis of the free damped vibrations in the first part of the thesis. Viscoelastic model parameters of two dampers with different rubber hardness are calculated using optimization methods. Temperature distribution inside the rubber part during the harmonic oscillation is calculated with the knowledge of previous values. Computational models together with a user interface are assembled in Matlab/Simulink software tool. Computational model results of the viscoelastic rubber damper are verified by measurements on a prototype diesel engine in the whole operating engine speed range. Torsional vibrations of the crankshaft with torsional damper are measured by POLYTEC laser rotational tools. The temperature distribution on the damper surface is obtained by Infratec VarioCAM thermographic system. Combustion pressures in the cylinder are measured by SMETEC Combi indication tools. Both the temperature distributions and combustion pressures are used for computational purposes. All the measurement procedures are described also in the thesis.
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Construction of molds for rubber molding
Bátrla, Martin ; Nohál, Libor (referee) ; Brandejs, Jan (advisor)
This Bachelor’s thesis contains the general body of knowledge related to theory of injection molds for rubber molding. There is also described a designing procedure of mold for rubber cuff which will be used as a protection against the dust and other impurities. The output is a 3D model of injection mold made in SolidWorks 2015 and 2D documentation of chosen parts.
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Specifics of forming using elastomers
Barák, Vít ; Peterková, Eva (referee) ; Podaný, Kamil (advisor)
The thesis contains a review of methods using elastomer tool, including the distribution of tools and suitability to the operations. Forming using elastomers is among the unconventional forming methods using flexible tool which is especially suitable for sheet metal forming. The material is used rubber and polyurethane. There are described properties, forming forces and other attractions of elastomers. The principle consists in replacing the fixed part of the tool flexible medium. Forming methods are divided to open tool forming and close tool forming, according to the construction of forming tool. Open tool forming includes bending and roll bending. Among the close tool forming methods is Guerin, Marform, Maslenikov, radial expanding and extrusion. The following are examples of tools and differences compared to conventional methods and liquids. The advantage of elastomeric tool is a low cost, simplicity and frugality to surface modified products. The disadvantage is a low life, low productivity and the use of large forming forces. Forming using elastomers has application in the prototypes and small series production.
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Rubber Damper Design for 4-cylinder In-line CI-engine
Sedlák, Aleš ; Svída, David (referee) ; Novotný, Pavel (advisor)
Design of a rubber damper for 4-cylinder in-line CI-engine is this aim of this thesis diploma. Thesis consists from several parts. First part describes technical solutions of dampers of torsional vibrations. Second part contains torsional vibrations analysis of crankshaft without damper. The last part of this thesis describes design of rubber damper and torsional vibrations analysis of crankshaft with damper.
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Design of a rubber coupling for railway applications
Blach, Jiří ; Prokop, Aleš (referee) ; Řehák, Kamil (advisor)
The diploma thesis deals with the design and stress-strain analysis of a flexible coupling composed of individual rubber-textile segments. This concept allows the manufacturer to simplify and unify the production thanks to the ability to use a single segment design for multiple coupling configurations and thus leads to a reduction in costs on the part of the manufacturer. From the consumer side this allows only mechanically or chemically damaged segments to be replaced instead of the entire coupling and saves costs for the potential user. The coupling assembly is primarily designed according to the parameters of intercity electric units and locomotives, however, the individual flexible segments are not limited by this use. When designing a coupling assembly, it is necessary to place requirements primarily on the high safety of all components. The operating mode, in which the relative displacement of the input and output shafts can occur, indicates a relatively wide range of transmitted loads which, if any assembly part is improperly designed, can cause problems leading to temporary putting the entire machine/vehicle out of order. The most critical areas of the assembly include the flexible segments, the bolt connections, the strength of the hubs and the spline joint for torque transfer. Last but not least, the requirements for the non-complex production of components must be taken into account, together with the assembly and maintenance without collision of the components and the necessary tools. In order to verify the above-mentioned requirements, stress-strain analyses are performed simulating the variation of operating load conditions. Due to the reduction of hardware requirements and computational time, together with the absence of experimentally measured data of rubber and PES codes, the flexible segments were modelled at a lower level with a reduced material model favouring the tensile properties of PES cords. However, this reduction provides a more conservative approach, as this use causes higher stresses on the steel components of the assembly. Subsequently, a stress analysis of the splined joint is performed. Due to the absence of specific shaft geometry models of commercial motors and gearboxes, a parallel splines were chosen for this purpose and designed according to the specified maximum torque. The last part of the thesis is focused on verifying the tensile properties of an individual flexible segment.
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Determination of Dependencies for Evaluation of Stiffness Measurements of Rubber Bearings
Beseda, Vojtěch ; Kubík, Roman (referee) ; Kalivoda, Milan (advisor)
The thesis deals with analysis of rigidity of rubber joint measurements. Characteristic, usage and behaviour of a rubber is described in the first part of the work. The following chapter describes problems and analyse production technology of the given component. The work continues by a preparation of several tests established based on information provided in the first chapter and from requirements of company. At the end, correlations and recommendations for appropriate measurement are concluded based on acquired data. The thesis is closed by a technological and economical evaluation which presents required cost for preparation, realization and analysis of tests.
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On the effect of tempering and storage conditions of rubber parts on final joint cohesion
Jílková, Ingrid ; Kalivoda, Milan (referee) ; Píška, Miroslav (advisor)
This bachelor’s thesis deals with an analysis of waxing phases occurrence on the surface of the technical rubber which is used in the automotive industry. The theoretical part of this thesis deals with a composition and manufacturing of the rubber. It is focused on the composition of rubber compounds and waxes. It explains technical properties, reasons (advantages) of the ingredients in the rubber components. Next, it also clarifies the substance of the wax and its use in relation to rubbers. The theoretical part also clarifies the storage of rubber parts and why is it desirable to identify the wax which is separated on free surfaces of rubber. The practical part deals with a suggestion of the identification methods for the waxes on the surface of rubber. It also presents the comparison of the possibilities of the methods used for the identification of wax and its evaluation.
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Investigation of storage conditions influence on adhesion of rubber bushings
Kvapil, Štěpán ; Muroň, Aleš (referee) ; Kandus, Bohumil (advisor)
The theoretical part of the thesis is focused on research on vulcanization and post-vulcanization, i.e. the production of rubber and the connection of rubber with metal using the latest technologies. This part serves as the theoretical basis for the development of the training base and the experimental part, which are part of the practical part. The training materials are serving for faster and more effective training of new staff and as a comprehensive set of information to the MAT center. The methodology of the manual is described in the main thesis and identical examples from this document are inserted in this thesis too. The experimental part focuses on the adhesion of rubber to the metal surface with subsequent evaluation. The whole problem from the preparation, post-vulcanization, tearing, through measurement to determination of the maximal storage life of sprayed rubber bearings is described.
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Test cell for ozone degradation of tires
Píza, Tomáš ; Veselý, Oldřich (referee) ; Brandejs, Jan (advisor)
This diploma thesis is occupy by assesment optimum method straining of tyres and then constructional concept of test cell for ozone degradation of rubber tyres with sizes from 13” to 15”. The final aim of this diploma thesis is construction of test cell which is based on choice of optimum method straining of tyres. The next output of this diploma thesis is concept of unit for ozone degaradation of tyres.
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