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Problems of the Expert Analysis of the Vehicle Movement and Braking Action in General Spatial Curve at Speed Higher than 50 km/h
Panáček, Vladimír ; Šachl, Jindřich (referee) ; Drahotský, Ivo (referee) ; Vémola, Aleš (advisor)
The present apparatus for the technical analysis of road accidents has no well-integrated information, recommendations or procedures of how to solve comprehensively the analysis of road accidents involving vehicles equipped with stabilization system of driving dynamics. The problem in the investigation of a vehicle movement in a curve is the ignorance of the contributions of vehicle dynamics intervention of the electronic stability system. Although some of the simulation software used in the analysis of road accidents makes it possible to take into account the modelled vehicle movement impacted by a stabilization system in the examined process, but the experts do not know what parameters should be entered in the numerical models of stabilization system in a computer programme. Therefore, the thesis investigates the issue of the expert analysis of vehicle riding and braking in a general spatial curve at speeds exceeding 50 kph with simultaneous examining the impact of electronic stability system chassis on vehicle driving dynamics. The thesis first deals with the solutions based on classical analytical methods, then dwells on experimental measurements in real conditions on testing grounds and, finally, addresses the use of computer simulation software in expert practice. Nevertheless, it is important to realize that no computer simulation software can be an absolutely unambiguous solver, and it is not enough to generate a computer simulation, but so obtained results should be evaluated and justified technically. Road accident analyst needs to know the impact of vehicle electronic stability control systems on vehicle movement. The thesis investigated the mutual relationship between the vehicle speed limit in a curve specified by analytical calculation and the vehicle speed in a curve experimentally detected by measuring the parameters of driving dynamics of a vehicle equipped with electronic stability system. The impact of selected electronic stability control systems of the chassis on the vehicle movement in the investigated processes in the curve was detected and quantified by driving experiments. Finally, the input values of significant quantities of computational models of the ESP simulation programs were found consistent with the results of experimental measurements in defined curves for the vehicles equipped with electronic stability systems. The results of the thesis can be used both in the expert and in the teaching activities.
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Specifics of accidents Agricultural Technology
Tamáši, Adam ; Polcar, Adam (referee) ; Vémola, Aleš (advisor)
Master’s thesis focuses on the specifics of agricultural machinery accidents. The introductory part defines agricultural machines and its basic characteristics. It also analyzes specific technical regulations that govern the use of these machines in traffic. The experimental part then describes the methodology and interprets the results of conducted experimental measurements on driving dynamics of a tractor with carried accessory. These measurements consist of a break test in straight line, evasion manoeuvre and acceleration while turning left. The focus was given to not just the acceleration values, but also to the influence of the carried accessory, the load on the front axle or the tire pressure. The analysis of the findings made compares the results with the driving dynamics of ordinary passenger cars and provides a detail dissection of the most frequent causes of agricultural machinery accidents.
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Impact of the Instantaneous Weight of Vehicles on their Stopping Distance
Motl, Jakub ; Ptáček,, Petr (referee) ; Vémola, Aleš (advisor)
This diploma thesis is engaged in analysis of braking process of vehicles, especially heavy utility vehicles, with regard to their instantaneous weight. This thesis features survey and division of braking systems and function of brakes including schemes and descriptions. Also there is introduce of some systems improving vehicle properties. Furthermore this work puts mind to possibilities of examination of brakes, measurement of braking distance and braking retardation namely in brake test rooms or by outdoor driving tests including descriptions of particular methods and equipment. There is also mention about legislative requirements for braking distance and braking retardation. The conclusion of this thesis compares numerically predicted braking distance and real braking distance measured for factual vehicle during outdoor driving test
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Analysis of a Vehicle Saleability
Hasmanová, Sabina Bohdana ; Leichmann, Marek (referee) ; Vémola, Aleš (advisor)
The object of this thesis is to focus on the major influences of vehicle saleability in Czech Republic in terms of the most important criteria, such as price, fuel consumption, colour etc. Part of the work will be arranged questionnaires. The survey indicates desirability of cars back for the last five years. This creates sales trend with a hint of future development.
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Detection of Braking Tracks using Laser-Induced Breakdown Spectroscopy (LIBS) and Laser-Induced Fluorescence Spectroscopy (LIBS + LIFS)
Prochazka, David ; Vémola, Aleš (referee) ; Pína,, Ladislav (referee) ; Kaiser, Jozef (advisor)
The aim of this work is to investigate the potential of Laser-Induced Breakdown Spectroscopy (LIBS) for identification of visually unrecognizable braking tracks. Identification of these tracks is based on different chemical composition of tire tread in comparison to road surface. The investigation was divided in several sequential steps – selection of suitable chemical element and its spectral line for break tracks identification; determination of the limits of detection and threshold intensity respectively for the selected chemical element; verification of LIBS ability to detect braking tracks on a real braking track. This testing braking track was prepared by exactly defined and described conditions. The detection was performed in two ways – laboratory analysis of tire treads particles collected via adhesive tape and in situ analysis via mobile apparatus. Results of both measurements showed that LIBS is able to detect visually unrecognizable braking tracks. Concepts of the devices capable of routine braking tracks identification for both possibilities were introduced.
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The Issue of the Competence of Drivers of Motor Vehicles to Drive on the Roads of the Czech Republic
Chodurová, Zuzana ; Kudláček, Jaroslav (referee) ; Vémola, Aleš (advisor)
The theme of this master’s thesis is The Issue of the Competence of Drivers of Motor Vehicles to Drive on the Roads of the Czech Republic. It includes an analysis of the current state legislative requirements for obtaining professional qualifications of drivers in the Czech Republic and in neighboring states and comparison of selected specifics of the issue. An analysis was made of traffic accidents in the Czech Republic and comparison of basic indicators of accidents with neighboring states. Based on the analysis of the current state, then the practical part includes a questionnaire survey and suggestion of measures for improving road safety.
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Analysis of set of factors affecting safe longitudinal distance between vehicles
Zemánek, Lukáš ; Kovanda, Jan (referee) ; Bradáč, Albert (referee) ; Vémola, Aleš (advisor)
The doctoral thesis deals with problems of a safe longitudinal distance between vehicles. It includes an analysis of a set of factors influencing the safe distance between vehicles and is concerned with a research of effect of many of these factors on observance of the safe longitudinal distance between vehicles. In connection with these factors, this work deals with the solution of this issue in neighbouring countries through statutory measures, then with statistical analysis of traffic accidents in the Czech Republic caused by non-observance of the safe distance, also problems of assistance systems operating in this area, and subsequently, based on the findings, there are recommended suggestions of actions to increase safety in this area of road transport.
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Strain and stress analysis of the car front part under impact loading.
Hrubý, Jaroslav ; Vémola, Aleš (referee) ; Vrbka, Jan (advisor)
This work deals with the stress and strain analysis of the car front part of Škoda Octavia II. generation under impact loading using an explicit formulation of finite element method (FEM). The aim of this work is examination of resistance of the car front part under this impact loading and comparison of the data, which were get out of the FEM simulation of the car impact on the rigid wall with methods, which are used in forensic engineering. The comparison of the FEM simulation of the car impact on the rigid wall will be provided with the correlation method and with the method of energetic grid.
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Specific Conditions for the Participation of Motorcycles in Road Traffic
Suchá, Klára ; Vémola, Aleš (referee) ; Coufal, Tomáš (advisor)
Abstract The main theme of this thesis is to discuss the specific conditions of motorcycles participation in traffic. Primarily the author of the processing of statistical data relating to road traffic accidents found the most frequent causes leading to the accident of motorcycles, set out a list of typical hazardous situations and provide an opportunity to prevent them, respectively propose the concrete steps for their reduction, while visual processing is done using by the Virtual CRASH software. Secondarily, it is then processed an overview by modern elements of active and passive safety of motorcycles and their effect on the reduction of traffic accidents, or reduce health risks as the consequences of road traffic accidents. Statistical data are then confronted with the subjective perception of participation in traffic, concretely with motorcycle riders. Their opinions are interpreted by the most frequent responses from the questionnaires, the results are included in the last part of this thesis. The objective of this work is in the comparison of both perspectives - statistical data and the opinions of motorcyclists - about the traffic situation in the Czech Republic. The result of this work is the more realistic view on the issue.
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