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Kinematics and elastokinematics of independent multi-link suspension of axle using flexible supporting elements
Vrána, Tomáš ; Kovanda, Jan (advisor) ; Ladislav, Ladislav (referee)
This thesis deals with elasto-kinematic properties of multi-link rear suspension
system, based on simulations. The creation of computational model and simulation of
elastokinematics are based on specialized modules of the HyperWorks software. The
thesis idea is to create new models and improve their properties.
The chapter introduction presents and discusses the current knowledge state in the
issue of elasto-kinematic characteristics of the vehicle suspension. Previously published
works are presented in this section. The following section defines basic terms, features
and design elements concerning the topic vehicle suspension and vehicle axle, which
can help readers to orientate in this field.
The first part of the thesis is focused on the collection of high-quality input data to
create the MBS computational model based on the real suspension components. The
determination of kinematic suspension points, experimental measurements of inertia
moments of supporting elements of the suspension and measurements of deformation
characteristics of rubber-metal bushings are presented in the thesis. There are also
measuring characteristics of force elements such as springs or shock absorbers. Then the
proposed method of measuring elasto-kinematic characteristics of the suspension using
testing machine for model validation is also introduced.
The second and main part is devoted to creating a new MBS simulation models of
multi-link rear suspension using HyperWorks system. The suspension model is
improved by successive steps, from kinematic model, through model with flexibility of
the bushings, to the complex model in which the flexible properties of all supporting
elements are reflected. The properties of the used models are described together with
arising calculation problems. The results discuss the impact of elements flexibility and
individual structural alternatives on elasto-kinematic characteristics of the suspension
system.
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Passive safety of vehicles with a focus on incompatible impacts.
Tulach, Pavel ; Kovanda, Jan (advisor)
This dissertation describes in detail the issue of passive safety related to the biomechanics of injuries and crash tests processed as well.
Statistics of accidents for the last 10 years, which show the maximum and minimum numbers of accidents and fatalities, are presented in the first chapter, "Overview of the current state of solved problematice. There is also briefly defined legislative relationship between the driver, as road users on the one hand and vulnerable pedestrians on the other hand. The issue of injury biomechanics and especially the serious injuries of body parts (organs) are elaborated in relevant chapter.
Methodological part of the thesis described and analyzed data from previously crash tests and serve as a basis for comparison with other experimental tests. Other tests means tests performed on the shock chamber. After evaluation and processing of measured data is to identify and describe the limits of the load, which is the human body when exposed to incompatible impact.
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Passive safety and influence of information technology
Mík, Josef ; Kovanda, Jan (advisor) ; Šatochin, Vladimír (referee)
Dissertation thesis deals with problems associated with information system focused on the developed pan-European emergency call system eCall. An improvement in the area of road vehicle safety through a better description of the traffic accident by eCall system are being solved in the dissertation. The work is focused on the frontal collision accidents of type M1. In the first part of the work, a current state of eCall system is described including architecture of the system and overview of related legislation. Further, a legislation related to the vehicle passive safety tests and methods of their evaluation are described. An overview of frontal collision tests with different collision obstacles is presented in the next part of the work. Results of these tests are further used in the analysis of accident severity estimation by eCall system. The works further studies suitability to use the data measured by the eCall system during an accident for the accident severity estimation. This study is based on the correlation analysis of measured accelerations and analysis of parameters of tested eCall unit.
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Vehicle sensoric systems
Altal, Rami ; Kovanda, Jan (advisor) ; Zewdie, Retta (referee)
The objective of the thesis is to analyze modern sensoric systems and assistance systems of active vehicle safety. In the beginning of the thesis it describes the working principles of individual sensors, their structures and their potential for driver assistance systems and in the following chapter it describes in detail some of the selected modern assistance systems. The final chapter describes the experiment, a simulation of adaptive cruise control function using the Lego Mindstorms NXT programmable robotics kit.
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Influence of passive safety features of the rear-seats passengers
Hůlka, Václav ; Kovanda, Jan (advisor) ; Tulach, Pavel (referee)
The number of traffic accidents is still increasing also due to the increasing number of cars moving on roads. As a result, car manufacturers are made to pay attention to safety more and more. Nowadays they do not deal only with the front seats area but they began focusin on the back seat area, too. The aim of this work was to create a summary of elements of the passive safety and of regulations connected with the back seat area. Practical part is dedicated to statistics and testing of biomechanical criteria of child dummies during crash tests using various elements of the passive safety. The aim was to clarify their influence on protection of occupants in a car during the crash.
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Analysis of impact of active safety elements in vehicles on pedestrian protection for traffic accident investigation
Vertaľ, Peter ; Kovanda, Jan (referee) ; Kropáč, František (referee) ; Vémola, Aleš (advisor)
Increase the probability of prevent road accidents by installing autonomous systems in a vehicles is the current trend in the field of active safety with a focus on pedestrian safety. The work deals with the evaluation of intervention of active safety systém for pedestrian detection assembled in series production. Benefit of active safety systems to prevent road accidents can be achieved, for example, early warning driver of a potential collision situation sufficiently in advance to reaction and post-maneuver (braking, yaw, ..). The evaluation of the intervention of active safety systems, which aim to prevent an accident with a pedestrian is necessary to experimentally evaluate the behavior of these systems. The main objective of this work is to test the selected systém based on different types of reál accidents. Atthe time of the measurements and present, are not for experts and specialists in the field of road traffic accidents publicly accessible data about the behavior of such a systém. The work aims to evaluate the behavior of the Volvo systém in inducing reál traffic situations. For the evaluation of this systém are precisely analyzed fatal traffic accidents with pedestrians in the urban area (speed of vehicles up to 60 km/h). Simulated traffic situations by their nature cover the most common critical situations in urban traffic. Expert community and the professionals who deal with the solution of traffic accidents receive this work valuable data to deal with such accidents. Based on these measurements give more expert input data to solve a collision with a pedestrian. The basis for understanding the behavior are created graphs of distance, speed and time at a key moment of the collision. These key moments include entry a pedestrians to driving corridor of the vehicle, system's response to conflict situations, warn the driver and then autonomously brake active safety systém
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STIFFNESS ANALYSIS OF FRONT PART OF THE VEHICLE
Coufal, Tomáš ; Kovanda, Jan (referee) ; Kohút,, Pavol (referee) ; Vémola, Aleš (advisor)
The thesis deals with the front part stiffness of modern vehicles, especially for the use in the field of forensic engineering in the traffic accident analysis. During the traffic accident analysis, an inquiry into the collision between vehicles is carried out which is an integral part of determining the energy loss of the vehicle at the impact, or more precisely the deformation energy expressed in the form of Energy Equivalent Speed (EES). In case of known stiffness of given part of the vehicle and based on the depth of deformation, it is possible to calculate the deformation energy, or more precisely EES corresponding with given damage of the vehicle. In the field of forensic engineering, the values of stiffness of individual vehicle components are not known and therefore, alternative methods are used to calculate the EES, they are outlined in the research part of this dissertation. However, the current methods of EES determination have some limitations when it comes to usability, and therefore, new EES calculation for the front part of the vehicle was designed in the research. It was based on the real crash test results using real stiffness characteristics of the front part of a vehicle. The front part of the vehicle is divided into individual areas and each of these parts is characterised by its own stiffness coefficient. The designed EES calculation can thus be also used for collisions with partial overlapping, taking into account the real stiffness of the damaged part of the vehicle, which was not possible with existing methods. In the research part of this dissertation, a computer programme to calculate deformation energy and EES was processed. It works with individual stiffness characteristics in given areas where the input data are entered by the user and include the depth of permanent front part deformation in individual areas, vehicle weight, the direction of an impact force and the friction coefficient on the contact surface. Considering the fact that the vehicle stiffness is also one of the control parameters at solving collisions in the PC-Crash simulation programme, which is used in forensic engineering practice for the analysis of a collision process, a supplementary computer programme was designed. Based on the above-mentioned input data, the supplementary programme can further calculate data for collision solving in the simulation programme, namely stiffness, restitution coefficient and the vehicle damage stated in the output report of the simulation programme. Based on these data, the expert thus has the opportunity to solve the collision of two vehicles in the simulation programme with as much preciseness as if it was a real collision.
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Compatibility of Vehicles in a Frontal Collision
Vašíček, Jiří ; Kovanda, Jan (referee) ; Coufal, Tomáš (advisor)
Thesis deals with the compatibility of vehicles in a frontal collision. The first section discusses about compatibility from different views. There are the physical processes used in the mechanics of impact. The second part is focused on solving the compatibility of vehicles in a frontal collision by crash analysis using the finite element method. Firstly there are described collisions of vehicles from different vehicle classes (small cars, lower middle class, Pick up / SUV) into the fixed barrier by the US NCAP. Furthermore there are simulated head-on collisions of vehicles from different vehicle classes. In the end there is shown the possibility of using data from crash tests to determine the EES.
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Analýza materiálových toků na makroekonomické úrovni s aplikací na mikroekonomickou úroveň a využití analýzy při rozpracování indikátorů trvale udržitelného rozvoje
České centrum čistší produkce, Praha ; Univerzita Karlova v Praze, Centrum pro otázky životního prostředí, Praha ; Ouředníková, Klára ; Krčma, Miroslav ; Christianová, Anna ; Kovanda, Jan ; Hák, Tomáš ; Moldan, Bedřich
Rozbor a kritické zhodnocení využitelnosti indikátorů materiálových toků pro rozhodovací procesy, zhodnocení indikátorů materiálových toků z hlediska jejich relevance k trvale udržitelnému rozvoji, zhodnoceni vztahu a srovnání silných a slabých stránek indikátorů materiálových toků ve srovnání s ostatními indikátory trvale udržitelného rozvoje. Posouzení míry spolehlivosti indikátorů materiálových toků kalkulovaných dle metodiky Eurostatu z hlediska dostupnosti dat potřebných pro jejich výpočet, správnosti těchto dat a jejich reprodukovatelnosti. Posouzení využití analýzy materiálových toků na makroekonomické úrovni pro nižší úrovně, jakými jsou úroveň region a podnik. Zhodnocení možného propojení účetnictví materiálových toků s podnikovým účetnictvím. Návrh úprav metodiky analýzy materiálových toků na makroekonomické úrovni, nutných pro její využití na regionální a podnikové úrovni.
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