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Utilization of biogas in transport
Strnadel, Bronislav ; Kučera, Pavel (referee) ; Vopařil, Jan (advisor)
The subject of this bachelor’s thesis is the utilization of biogas as a fuel for vehicle engines. First of all, methods of production, upgrading and utilization of biogas are explained. Then the situation in the Czech Republic and in Sweden is compared. Next part of the thesis is focused on the vehicles which burn upgraded biogas or natural gas vehicles. Their construc-tion and the function of fuel system are described in detail. The dependence of shape of combustion chamber on engine performance and the issue of protection of valves and their seats are described in this chapter. In the last part, a business case study of utilization of bio-gas from a biogas station is elaborated.
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Design of chassis for an electric minibus
Strnadel, Bronislav ; Ramík, Pavel (referee) ; Štětina, Josef (advisor)
The theoretical part of the master thesis is devoted to electric vehicles from their history through sources of electric energy and a swapping battery system to electric buses and autonomous driving. In the practical part the concept of autonomous electric minibus with the calculation of battery capacity are described. Furthermore, the attachment of battery to chassis and the idea of automatic swap are designed. In the last chapter the design of chassis itself can be found together with the FEM analysis.
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Design of chassis for an electric minibus
Strnadel, Bronislav ; Ramík, Pavel (referee) ; Štětina, Josef (advisor)
The theoretical part of the master thesis is devoted to electric vehicles from their history through sources of electric energy and a swapping battery system to electric buses and autonomous driving. In the practical part the concept of autonomous electric minibus with the calculation of battery capacity are described. Furthermore, the attachment of battery to chassis and the idea of automatic swap are designed. In the last chapter the design of chassis itself can be found together with the FEM analysis.
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NEW APPROACH TO STRESS-STRAIN CURVE PREDICTION USING BALL INDENTATION TEST
Brumek, J. ; Strnadel, B. ; Dlouhý, Ivo
This work is concerned with the method for predicting stress-strain behavior of material using instrumented indentation technique. High strength low alloy steel with different thermal treatment was taken into the analysis. Heat treatment for the steel was performed to obtain different mechanical properties. Assessment of mechanical properties was done by using inverse technique of the finite element analysis. The results were confronted with conventional test parameters and prediction procedure defined such Automated Ball Indentation Technique (ABIT). Comparison of the material curves shows good agreement with tensile test properties which makes this non-destructive method suitable for industrial application.
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Utilization of biogas in transport
Strnadel, Bronislav ; Kučera, Pavel (referee) ; Vopařil, Jan (advisor)
The subject of this bachelor’s thesis is the utilization of biogas as a fuel for vehicle engines. First of all, methods of production, upgrading and utilization of biogas are explained. Then the situation in the Czech Republic and in Sweden is compared. Next part of the thesis is focused on the vehicles which burn upgraded biogas or natural gas vehicles. Their construc-tion and the function of fuel system are described in detail. The dependence of shape of combustion chamber on engine performance and the issue of protection of valves and their seats are described in this chapter. In the last part, a business case study of utilization of bio-gas from a biogas station is elaborated.
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Local approach in mechanical properties prediction
Brumek, J. ; Strnadel, B. ; Dlouhý, Ivo
Indentation technique was focused on the prediction of the strain hardening behaviour of carbide steels. An improved technique to determine the plastic properties of material from the load-displacement curve from a ball indentation test was proposed. The time severity for the search for an optimal solution for a non-linear constitutive model is dependent on a number of design variables. Common methods like gradient methods or linear programming can fail due the fact that they drop to the local minimum. The advantage of a genetic algorithm does not require knowledge of the target function. Proposed method was applied to the data from the instrumented indentation technique. Results were found to be in good agreement with the data from conventional, standard tests, and in less time.
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Assessment of Pressure Vessels Safety
Macurová, K. ; Tichý, R. ; Strnadel, B. ; Dlouhý, Ivo
Conditions of pressure vessels breach are investigated in the present paper. Safety of the modified criteria application of Leak Before Break when a residual stress is found in the vessel material is analysed. Design criterion is based on a critical crack length which must be less than the thickness of the vessel wall. Superposition of residual stress, which occurs in the production of a vessel by impact extrusion, and the hoop stress caused by the internal pressure significantly affects the life and conditions of technical use. Size and character of the distribution of residual stresses were determined experimentally by use of the hole-drilling method. The numerical simulation and mathematical calculations have been carried out applying ANSYS and MATLAB software. The main attention was focused on the application of residual stress in the numerical analysis based on values obtained by the experimental measurements by hole–drilling method.
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Nonlinear modeling of stable crack growth
Brumek, J. ; Strnadel, B. ; Dlouhý, Ivo
This paper presents numerical study to predict crack growth rate under fatigue loading in a high pressure cylinder wall made of high strength steel. Experimental fatigue crack growth data on three point bending test samples. were applied to simulate and predict crack growth process using detailed three dimensional parametric finite elements models. The fatigue crack propagation was based on linear elastic fracture mechanics and stress intensity factor determination. Finite element model provides results of crack growth analysis optimized for the stress levels of operating pressure level. Results are plotted on a-N. Results were compared with an experimental fatigue test.
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Fraktální anisotropie a heterogenita lomových ploch oceli
Strnadel, B. ; Dlouhý, Ivo
The change in the fractal dimension of the fracture surface demonstrates a wavy character and dispersion depending on the microstructural state of the tested steel. The results of the fractal analysis in the crack growth direction and across the entire crack front were used as the basis for a reconstruction of the geometry of the fracture surface. The competing effects of transgranular and intergranular brittle fracture may lead to increased roughness of the fracture surface and its fractal dimension.
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