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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Kinematika a elastokinematika nezávislého víceprvkového zavěšení nápravy se zohledněním poddajnosti nosných prvků / Kinematics and elastokinematics of independent multi-link suspension of axle using flexible supporting elements

Vrána, Tomáš January 2016 (has links)
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.
52

Adaptivní řízení magnetoreologických tlumičů / Adaptive control of magnetorheological dampers

Míša, Jiří January 2020 (has links)
The topic of this master´s thesis is the design of adaptive damping algorithm for the prototype magnetorheological dampers, which are used for Formula Student vehicle. The prime output is the development and optimization of the control algorithm which included usage of the MBS software and real data from race track. Temperature compensation to supress the effect of dynamic viscosity of magnetorheological fluid due to the increase in operating temperature and testing of the vertical dynamic of the car on 4 - post test rig was realized as well. The main goal was to obtain better control of the car in transient situations and increase usability of tires via changes in damping based on actual conditions and status of the vehicle.
53

Návrh jednoválcového zážehového motoru / Design of Single Cylinder 4-stroke SI Engine

Číž, Petr January 2008 (has links)
Thesis deals with design of the experimental single-cylinder spark ignition engines for research purposes. The main purpose of this work is the design crankcase. Summary of possible constructions of spark ignition engines is included. Basic dimensions and 3-D design of the experimental engine resulted from the summary. The numerical analysis of proposed crankcase in ADAMS (MBS) and ANSYS (FEM) software environment is also part of the work. Generally, the proposed solution of the experimental engine was focused on the universality and simplicity of the design.
54

Řešení pohonu vačkového hřídele pomocí ozubených kol / Solution of Gear Drive for Camshaft

Barvík, Rostislav January 2010 (has links)
For dimensions of crankshaft drive Zetor engine, which is solve by a helical gear drive will be created a dynamic model in MBS (multi body system) and perform analyses. The same way will be created a dynamic model for a spur gear system. In conclusion will be confrontation both of these drive solutions.
55

Řešení dynamiky pohonné jednotky ve vozidle / Solution of Powertrain Dynamics in Vehicle

Hodas, David January 2014 (has links)
The main aim of this diploma thesis is to evaluate and select the most appropriate option how to mount a power unit in Formula Student vehicle. It assesses an overall dynamic behaviour of a drive unit mounted in student formula. At the end of the final thesis is an assessment of proposed engine mount variants. The study of parameters that most influence engine vibrations can be seen there.
56

Simulační posouzení možností tlumení osy X těžkého obráběcího stroje / Simulation Assessment of X Axis Damping Possibilities of Heavy Machine Tool

Štetina, Jakub January 2014 (has links)
This master's thesis deals with the simulation assessment of axis X damping possibilities of Heavy Machine Tools. CAD model has been provided by company TOSHULIN a.s. In the thesis, there is described modelling of axis X as multi body system consisting of rigid and flexible bodies. The main goal is to create simplified model and get the information for strategic decision of manufacturer about damping possibilities of axis X. For the solution has been used several software products: SolidWorks 2013 - for simplifying the CAD models, Ansys 14.5. for modelling od flexible bodies, MSC.Adams for modelling multi body systems and Matlab 2012 for data processing and optimization.
57

Tenzometrické závěsy kol Formule Student / Strain Gauge Suspensions of Formula Student

Stariak, Gabriel January 2016 (has links)
The diploma thesis deals with examinations of forces which are acting from road surface on tyres. The aim is to design and build measuring circuit which measure forces in front suspension. The thesis deals with designing of mathematical model in addition describes problematic of strain gauge sensors, their calibration and verification measure in details. The results are data obtained from static and dynamic measurement and outputs from multi-body system softwares. The results are evaluated and compared at conclusion.
58

Vliv pružnosti rozvodového mechanismu na pohyb ventilu / Influence of the Valve Train Flexibility to the Single Valve Motion

Řehůřek, Lukáš January 2016 (has links)
The aim of this thesis is a comparing single valve train motion (SVT) and complete valve train motion with a flexible camshaft focused on dynamic characteristics. In this thesis is also performed kinematics analysis in the VALKIN software. Dynamic analysis is solved in the MBS software Virtual Engine. Influences to the valve train motion are described in the conclusion
59

Virtuální prototypy hnacích ústrojí / Virtual Prototypes of Drivelines

Janoušek, Michal January 2016 (has links)
The thesis deals with computational modelling of heavy duty off-road vehicle driveline components. The thesis is divided to two main parts. The first part deals about modal analysis of selected driveline components. MBS computational study was performed based on modal analysis results. The second part of thesis deals with experimental verification of computational model. Pass-by noise and vibration measurement was performed. Measured signals were processed in frequency domain to find noise and vibration sources.
60

Model Order Reduction in Structural Mechanics / Coupling the Rigid and Elastic Multi Body Dynamics

Koutsovasilis, Panagiotis 06 October 2009 (has links) (PDF)
Gegenstand dieser Arbeit ist die Forschungsdisziplin, welche in der Strukturmechanik als Modellordnungsreduktion bekannt ist. Im Mittelpunkt stehen Kopplungsprozesse von starren und elastischen Mehrkörpersystemen - sowohl in theoretischer Hinsicht als auch bezüglich der praktischen Realisation im Rahmen des Finite-Elemente-Programms ANSYS und des Mehrkörpersimulationsprogramms SIMPACK. Eine Vielfalt von strukturerhaltendenMOR-Methoden wurde zum Zwecke des Überblicks dargestellt. Darüber hinaus findet sich eine Kategorisierungsmethodik in Hinsicht auf den später beschriebenen FEM-MKS-Kopplungsprozess. Die Effizienz der MOR-Methoden wird sowohl hinsichtlich der Qualität der ROM als auch bezogen auf die hierfür benötigte Rechenzeit bemessen. Aus diesem Grunde wurden etliche MOR Schemata dargelegt, mit dem Ziel, den Effizienzfaktor während der Berechnung eines ROMs zu maximieren, das heißt maximale Qualität und minimale Rechenzeit zu erzielen. Die Validierung der dynamischen ROM-Eigenschaften basiert auf der Anwendung der sogenannten Modellkorrelationskriterien. Dies wurde an vier Anwendungsbeispielen aus dem Feld der Strukturmechanik getestet: der 3D-Balkenstruktur, der UIC60-Schiene, dem Pleuel und der Kurbelwelle. Die Anwendung der diagonal perturbation-Methodik verbessert die Kondition der Steifigkeitsmatrix eines Modells, von beiden Arten von Lösungsprozeduren, d.h. direkte und iterative Verfahren, betroffen sind. Die dynamische Bewegung mechanischer MKS wird als ein Index-3-DAE-Systemformuliert und die Information über die elastischen Körper wird in Form der sogenannten Standard Input Datei in einen MKS-Code transferriert. Die Einführung des Back-projection-Ansatzes ermöglicht die weitere Verwendung bestimmter ROM-Typen, derren assoziierten physikalische Eigenschaften unangemessen definiert wurden. Zum Abschluss werden die theoretischen, modellierenden und numerischen Fortschritte der Arbeit resümiert und kombiniert im Sinne der Model Order Reduction Package Toolbox (MORPACK). Die Matlab-basierte MORPACK-Toolbox ermöglicht den FEM-MKS-Kopplungsprozess für die Verwendung von ANSYS und SIMPACK. Hierin sind ein Großteil der zuvor erläuterten Erweiterungen eingeschlossen. Mit Hilfe der zwei integrierten inneren MOR- und SID-Schnittstellen als auch der vier Anwendungsebenen wird der Import von freien oder eingespannten ROM in SIMPACK ermöglicht. / The research discipline referred to as the Model Order Reduction in structural mechanics is the topic of this Thesis. Special emphasis is given to the coupling process of rigid and elastic Multi Body Dynamics in terms of both the theoretical aspects and the practical realization within the environment of the commercial Finite Element and the Multi Body Systems software packages, ANSYS and SIMPACK respectively. In this regard, a variety of structure preserving Model Order Reduction methods is presented and a categorization methodology is provided in view of the later FEM-MBS coupling process. The algorithmic scheme of several of the MOR methods indicates the capability of generating qualitatively better Reduced Order Models than the standardized Guyan and Component Mode Synthesis approaches. The efficiency of a MOR method is measured in terms of both the quality of the ROM and the associated time required for the .computation Based on the application of the, so called, Model Correlation Criteria the efficiency of the MOR schemes is tested on four application examples originating from the area of structural mechanics, i.e. the 3D elastic solid bar structure, the UIC60 elastic rail, the elastic piston rod, and the elastic crankshaft model. Herewith, the superiority of alternative MOR schemes in comparison to Guyan or CMS methods is demonstrated in terms of the ROM?s quality and the computation time by the use of either the one-step or the two-step MOR algorithms. Numerous of the FE discretized structures suffer from the, so called, ill-conditioned properties regarding the associated stiffness matrix. On one hand, the direct solution of a MOR method might produce erroneous ROMs due to the associated truncation phenomenon and on the other hand, any kind of iterative approach suffers from vast computation times. The application of the diagonal perturbation methodology improves the condition properties of the model?s stiffness matrix and thus, both kinds of the aforementioned solution procedures are affected. The back-projection approach is introduced, which projects the ROM belonging to the Non physical subspace reduction-expansion methods category back onto the physical configuration space and thus, enabling its further usage in a MBS code, e.g. SIMPACK. Finally, the theoretical, modelling, and numerical advancements are combined in terms of the Model Order Reduction Package. The Matlab-based MORPACK toolbox enables the FEM-MBS coupling process for the ANSYS-SIMPACK utilization and herewith, several of the aforementioned enhancements are included. With the help of the two integrated inner interfaces, i.e. MOR and SID, as well as four application levels, the import into SIMPACK of alternatively free or fixed ROMs is enabled. The functionality of MORPACK is demonstrated based on two application examples, namely, the 3D elastic solid bar and the UIC60 elastic rail, the dynamic properties of which are validated prior to their import into SIMPACK.

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