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Dissertations / Theses on the topic 'Suspension geometry'
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Minaker, Bruce P. "Active geometry suspension for road vehicles." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ59533.pdf.
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Arana, Remirez Carlos. "Active variable geometry suspension for cars." Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/41040.
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This thesis investigates the characteristics and performance of a new type of active suspension for cars through modelling, simulation, control design and experimental testing. The Series Active Variable Geometry Suspension (SAVGS) concept is first put in context by reviewing the history and current trends in automotive suspensions. Its potential is then critically evaluated and work is carried out to maximise its performance for various suspension functions. A multi-model multi-software modelling and simulation approach is followed throughout the thesis in order to cross-check and substantiate simulation results in the absence of experimental data. The simpler linear models are used to inform the selection of suitable parameter sets for the case studies, to synthesise control systems and to qualitatively validate the more complex, nonlinear multi-body models. The latter are developed as a platform to virtually test the system and its control algorithms. When possible, these tests are based on standard open-loop test manoeuvres and on standardised external disturbances. The SAVGS-retrofitted suspension displays a very nonlinear behaviour, which is at the same time a liability and an opportunity from the point of view of control. Nevertheless, different linear control techniques are effectively applied to improve various suspension functions: PIDs are applied to the lower frequency suspension functions such as mitigation of chassis attitude motions, and the H∞ framework is applied to the higher frequency suspension functions such as comfort and road holding enhancement. In all cases, a cascade control approach is employed, and mechanisms are implemented to ensure that physical and design actuator constraints are always respected. This thesis also covers the design and construction of a quarter-car experimental test rig facility. Step-by-step recommendations for its refinement as well as a testing plan are also outlined.
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Bujalski, Waldemar. "Three phase mixing : studies of geometry, viscosity and scale." Thesis, University of Birmingham, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323109.
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One-, two- and three-phase mixing systems have been extensively studied. The experiments were performed in a range of standard (baffled) vessel geometries of diameter varying between 0.22 - 1.83 m. Rushton disc turbines and mixed flow impellers (both pumping directions) were fully investigated. Water and glucose solution (~ - 120 mPas) were employed. For single phase systems, the work has shown that the power number of disc turbines depends on disc thickness and scale of vessel. For the mixed flow agitators the power number is dependent upon the blade thickness and (D/T) ratio. Correlations enabling the ungassed power number to be calculated as a function of these parameters are given. For gassed systems, the power drawn by each type of impeller is explained by local impeller hyarodynamics (cavity structure) and the bulk flow pattern. The fiooding-Ioading transition (NF) and the complet~ dispersion condition (NeD) have also been studied. A large mixed flow impeller (6MFU45 ; D - T/2) with a large ring sparger is the most energy efficient at NF and NCD speeds as compared with the other geometries studied and correlations enabling the prediction of NF and NCD for all geometries studied are presented. Hold-up correlations are also given for each impeller firstly as a function of specific energy dissipation rate and superficial gas velocity and secondly as' a function of agitator speed and volumetric gassing rate. For each impeller, each method is equally good statistically for scale-up but the latter is more explicit. All impellers give approximately the same hold-up under equal specific power inputs and superficial gas velocity but there are small but statistically significant differences. These differences are discussed. For solid-liquid systems, correlations in the literature for the calculation of the minimum speed to just suspend solids, NJS ' are tested for each system geometry with glass Ballotini particles. The correlation proposed by Chapman et al. is shown to fit the present experimental data best. The specific power input per unit mass (ET)JS - constant, is proposed as a scale-up criterion for solids suspension. Large 6MFD45 (D - T/2) is the most energy efficient for suspension but 6MFU45 (D - T/2) is only slightly worse. In the three-phase mixing systems, the 6MFD 45 , D - T/2, is most energy efficient for solid suspension (ET)JSg' at low gassing rates (up to 1 vvm) but exhibits large flow pattern and torque fluctuations. Above _ 1 vvm, 6MFU45 (D = T/2) becomes the most energy efficient for solid suspension. In addition the minimum impeller speed for solid suspension NJSg for this impeller is almost independent of gassing rate and gives very stable flow patterns and torque. output throughout the whole gassing range. Again (eT)JSg - const is the recommended scale-up criterion for solids suspension under gassed conditions. Large (D - T/2) impellers are found to be more energy efficient and correlations for predicting N 45 45 . JSg for 6DT. 6MFD and 6MFU are obta~ned. Increase in liquid viscosity has a rather small effect on gas dispersion. Up to 120 mPas: (N) Q:I (N ) and (N ) Q:I F viscous F water CD viscous (NCD) water uO.06 On the other hand, viscosity has a significant effect on NJS and 3 to 5 times more energy is required for solid suspension at 120 ,mPas.
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Ness, Christopher John. "Suspension rheology and extrusion : a discrete element method study." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/20392.
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A suspension is a fully saturated mixture of discrete solid particles and interstitial liquid. Examples of suspensions include pastes, slurries, cement, food-spreads, drilling fluids and some geophysical flows. The present work focusses on granular (as opposed to colloidal) suspensions, which we define as those for which the thermal motion of the solid particles is negligible. Despite such ubiquity in industry and nature, our understanding of the mechanical properties of suspensions lags behind that of their constituent solid and liquids. In this thesis, the discrete element method is used to simulate suspension flow in shear, capillary and constriction geometries, mapping and characterising the fundamental flow, or rheological, regimes. As a starting point (Chapter 2), we consider an established regime map for dry granular materials, appropriate for flows of sand, grains and dry debris. Taking guidance from shear flow simulations that consider the lubricating effect of an interstitial liquid, we recast the regime map for a general suspension, elucidating flows comparable to the dry material or to a viscous liquid, dependent on the shear rate, liquid viscosity and particle stiffness. We give an account of the microstructural traits associated with each regime. Motivated by recent groundbreaking theoretical, computational and experimental work, we incorporate the emerging picture of frictional shear thickening into our regime map (Chapter 3). Our shear flow simulations capture the shear thickening behaviour and demonstrate that it may, in principle, occur in any of the identified flow regimes. Our simulations of time-dependent shear flows (Chapter 4), specifically flow reversal, provide a detailed micro-mechanical explanation of a longstanding and previously unexplained experimental finding, guiding future experimentalists in decomposing the particle and liquid contributions to the viscosity of any suspension. Indeed, the findings have already been exploited in the devising of an experimental protocol that has successfully proven the dominance of particle contacts in driving shear thickening. We next consider suspension flow in a microchannel (Chapter 5), finding that the identified shear flow regimes are locally applicable to flows in complex geometries under inhomogeneous stress conditions only when the local mean shear rate exceeds temporal velocity fluctuations. A more comprehensive description is therefore required to fully characterise the flow behaviour in this geometry. Finally (Chapter 6), we simulate pressure driven suspension flow through a constriction geometry, observing highly inhomogeneous stress distributions and velocity profiles. The roles of particle and fluid properties are considered in the context of an industrial paste extrusion process.
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Arensen, Bruce (Bruce Edward). "Design and analysis of the front suspension geometry and steering system for a solar electric vehicle." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/92663.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014.Cataloged from PDF version of thesis.
Includes bibliographical references (page 43).
A study on the design of the front suspension geometry and steering system to be used in a solar electric vehicle. The suspension geometry utilizes a double wishbone design that is optimized to fit in the space constraints of the vehicle. The steering system consists of a rack and pinion connected through tie rods to the steering knuckles, largely optimized based on the space within the vehicle. The final suspension geometry consists of upper and lower wishbone lengths of 4.25 inches and 3.75 inches, respectively. This system is optimized to maintain a proper camber angle and minimize scrub due to track distance changes throughout the travel of the suspension. The geometry of the steering system is designed to fit in the vehicle while achieving a near- Ackermann steering condition. The steering knuckle and steering rack extenders, both made out of Aluminum 6061-T6, are designed based off of this geometry and are optimized for weight and machinability.
by Bruce Arensen.
S.B.
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Vávra, Radek. "Optimalizace kyvadlové nápravy automobilu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-231769.
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This thesis is concerned with the design of Škoda 130 RS rear Semi-Trailing Arm Suspension and fixtures on the body. The main requirement of this thesis is to reduce weight of suspension. It is carried out the kinematic analysis and optimization of the kinematic. The construction part of this thesis provides a design of suspension based on the analysis of forces acting on the car wheel. Last part of the thesis includes of new rear suspension stress analysis.
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Martínek, Tomáš. "Zavěšení kol sportovního automobilu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-229639.
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This thesis deals with design of front and rear suspension of single-seater sports car. Design and optimization of geometrical parametres of axles is followed after theoretical introduction. Another section is concerned with calculation of the vehicle suspension and design of the steering. The construction of individual components is described in the final section.
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Zubíček, David. "Návrh podvozkové skupiny vozu Formule Student." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-254225.
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Diploma thesis deals with comparison of different types of tyres destined for Formula Student vehicle. Comparison is from view of chosen characteristics and from view of simulations for one lap. Thesis deals with kinematics design of suspension according to chosen tyre and according to improvement of car ability of monopost Dragon 6
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Dvořák, Martin. "Měření geometrie a kinematiky zavěšení s využitím optických scannerů Tritop a Atos." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230350.
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The diploma thesis is focused to possibility utilizing of optical scanners TRITOP and ATOS for set up geometry of wheels. In background research are described the most important parameters of wheel suspension and devices for measuring these parameters. Practical part is concerned with progression of measurement, results and with determination coordinates of kinematic points. These points are made 3D model of forward and backward suspension wheels. This model helps to make kinematic characteristics and its progression due to attitude of wheel. In last part is described possibility to utilizing of optical scanner ATOS to common measurement of geometry wheels.
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Vojtěšek, Aleš. "Měření odklonu kola během jízdy." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-231779.
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The subject of this master's thesis is design measurement and measure change wheel camber angle during driving. For this task were used parts from Corrsys-Datron and remaining elements needed to be manufactured. With complete system measurements were done and outputs data were displayed by Matlab and evaluated. Based on data evaluation is possible exactly determine relative position of the wheel to the road surface and to the body of vehicle.
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Birk, Juliane. "Binäre kolloidale Suspensionen in eingeschränkter Geometrie." [S.l. : s.n.], 2003. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB10547332.
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Bubeck, Ralf. "Paramagnetische kolloidale Suspensionen in eingeschränkter Geometrie Laborbericht /." [S.l.] : Universität Konstanz , Fakultät für Physik, 1997. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB8501066.
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Atashpendar, Arshia [Verfasser], and Tanja [Akademischer Betreuer] Schilling. "Geometric percolation and electrical conductivity in suspensions of conductive nanoparticles." Freiburg : Universität, 2021. http://d-nb.info/1227187483/34.
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Urban, Marek. "Návrh zavěšení kol Formule Student." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-417557.
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Tato práce se se zabývá návrhem kinematiky zavěšení kol obou náprav. Na základě analýz jízdních dat, multi-body simulací v softwaru Adams Car, simulací v Matlabu a analytických kalkulací v Mathcadu, je navržena řada změn s cílem zlepšit jízdní vlastnosti vozu Formule student, tyto změny jsou následně implementovány do CAD modelu vozu. Jednotlivé změny kinematiky náprav jsou provedeny na základě analýzy konkrétního problému, který se snaží řešit. Jednou z problematik je zástavbová náročnost systému odpružení a zavěšení zadních kol, zde je cílem snížit hmotnost, výšku těžiště a moment setrvačnosti. Další problematikou je geometrie předního kola, kde je cílem zlepšit využití pneumatik a snížit síly v řízení. Dále se práce zabývá simulacemi elastokinematiky zadní nápravy, součástí je také návrh měřícího zařízení. V poslední části je zkoumán vliv provedených změn i elastokinematiky na jízdní dynamiku vozu v ustálených stavech za pomocí MM metody simulované s modelem celého vozu v Adams Car a zpracované v Matlabu.
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Moravec, Jan. "Přední nezávislá náprava pro autobus." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2008. http://www.nusl.cz/ntk/nusl-227878.
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In those diploma work was solved problems of independent trapezoidal axletree for low-floor bus - NB12 CITY firm SOR Libchavy s.r.o . Work was divided into two main features: solving wheel-suspension kinematics and strenght calculation sorted parts of wheel suspension by the help of finite element method. There was effected fatigue calculation sorted parts of wheel suspension according to „Resetova metoda“ of predicting fatigue damage flowing from so – called cutaway methodics of fatigue tests at the close of this work.
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Bouillot, Jean-Louis. "Etude de suspensions bidimensionnelles par une methode d'analyse d'images : statistique et geometrie des amas." Aix-Marseille 1, 1987. http://www.theses.fr/1987AIX11081.
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Barreto, Marco Antonio Zanussi. "Dinâmica longitudinal : efeitos da geometria de suspensão nas mudanças de atitude da massa suspensa e os esforços nos elementos da suspensão." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/18/18135/tde-22122005-165842/.
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Este trabalho tem como objetivo estudar a influência da geometria de suspensão do veículo nas atitudes da massa suspensa. Apresenta um confronto entre obras e autores e está segmentada em três partes; onde na primeira parte são definidos os conceitos básicos como dive, squat, lift, anti-dive, anti-squat, anti-lift e equivalente trailing-arm; na segunda parte são apresentadas as limitações e os novos conceitos definidos por R. S. Sharp e na terceira parte é apresentado o modelo dinâmico bidimensional introduzido por Fu-Cheng Wang. Apresenta um modelo virtual em sistema de multi-corpos desenvolvido no programa ADAMS, com todos os subsistemas que compõe um veículo completo. Inova ao trazer como objeto de estudo um veículo de competição (fórmula SAE) que possui como particularidade o sistema de suspensão push-rod. Surpreende com os resultados obtidos, pois, contrariam os conceitos básicos encontrados na maioria dos livrosThis work has objective study the influence of suspension geometry on the sprung mass attitudes. It presents a confrontation among works and authors and this segmented in three parts; where in the first part the basic concepts are defined, dive, squat, lift, anti-dive, anti-squat, anti-lift and equivalent trailing-arm; in the second part the limitations are presented and the new concepts are defined for R. S. Sharp and in the third part are presented the bidimensional dynamic model introduced by Fu-Cheng Wang. It presents a virtual model in system of multi-bodies developed in the program ADAMS, with all the subsystems that composes a complete vehicle. It innovates when bringing such object to study one vehicle of competition (formula SAE) that it has a particularity suspension system push-rod. It surprises with results because its opposite of the basic concepts which is present in the majority of books
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Gautero, François. "Quatre problemes geometriques, dynamiques ou algebriques autour de la suspension." Habilitation à diriger des recherches, Université Blaise Pascal - Clermont-Ferrand II, 2006. http://tel.archives-ouvertes.fr/tel-00486417.
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Les trois chapitres de ce texte traitent quatre problemes de nature geometrique, dynamique ou algebrique, ayant un lien avec le procede de suspension (ou mapping-torus). Le premier chapitre presente un theoreme de combinaison general pour les graphes de groupes relativement hyperboliques (Gromov, Farb). Le deuxieme chapitre aborde deux questions de dynamique topologique : d'une part la generalisation, aux applications continues de graphes, de la notion de type d'orbite (Sharkovskii, Boyland) ; d'autre part la caracterisation de l'existence d'une structure de suspension pour certaines surfaces branchees (Williams). Le troisiµeme chapitre traite de la recherche de caracterisations, combinatoires ou dynamiques, des automorphismes geometriques parmi les automorphismes du groupe libre.
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Pinto, Lindomar. "Efeito das condições de operação e da geometria do reator sobre a distribuição de tamanhos de partícula de uma polimerização em suspensão." Florianópolis, SC, 2006. http://repositorio.ufsc.br/xmlui/handle/123456789/89309.
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Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia QuímicaMade available in DSpace on 2012-10-22T19:19:17Z (GMT). No. of bitstreams: 1 225992.pdf: 665851 bytes, checksum: de89fb0caa290ef509c68014bf439d05 (MD5)
Para a polimerização em suspensão, o conhecimento das condições de mistura no reator é um fator crítico, pois a distribuição de tamanhos das partículas (DTP) produzidas em suspensão está diretamente relacionada à fluidodinâmica no reator. Segundo Vivaldo-Lima et al. (1997), a mais importante tarefa na operação prática de polimerização em suspensão é o controle da DTP final, particularmente nos casos de poliestireno expansível (EPS), onde as próprias partículas produzidas ao longo do processo são o produto final. Portanto, o estudo da influência da geometria do reator e das condições de mistura durante a polimerização em suspensão em condições de operação similares a utilizada na indústria sobre a DTP é extremamente relevante para um melhor controle sobre o processo. Há poucas referências na literatura sobre a modelagem da evolução da DTP em tal sistema de polimerização, bem como estudos experimentais sistemáticos que correlacionem as variáveis de operação com a distribuição de tamanhos de partículas (DTP) de uma polimerização em suspensão, especialmente sob condições próximas às industriais com alto "holdup" (fração volumétrica de monômero em relação ao volume total do meio reacional). Neste trabalho foi realizado um estudo experimental sobre o efeito das variáveis operacionais, velocidade de agitação, posição do impelidor e a razão do volume de monômero/volume do meio reacional ("holdup") sobre a Distribuição de Tamanhos de Partícula (DTP) final obtida pela polimerização de estireno em suspensão. Os dados experimentais mostraram que o "holdup" apresenta um efeito significativo sobre a DTP e que a diminuição deste, leva a obtenção de tamanhos de partículas maiores. A velocidade de agitação e a altura do impelidor em relação ao fundo do reator não apresentam efeitos tão significativos. Porém, ao aumentar estas duas variáveis há uma clara tendência no deslocamento da DTP para partículas menores. Através do tratamento estatístico dos dados experimentais, comprovou-se os efeitos de cada variável sobre o diâmetro médio de Sauter. Os modelos estatísticos obtidos para cada faixa de tamanho e para o diâmetro médio de Sauter também apresentaram uma boa reprodutibilidade em relação aos dados experimentais. In a suspension polymerization, the knowledge of the mixing effects in the reactor is a critical point, as the particle size distribution (PSD) produced by suspension polymerization is related to the fluid dynamics of the reactor. According to Vivaldo-Lima et al. (1997), the most important issue in the practical operation of a suspension polymerization is the control f the final PSD. This is particularly important in the case of the expandable polystyrene (EPS), where the particles produced during the suspension are the final product. Therefore, the study of the effect of the reactor geometry and mixing conditions during a suspension polymerization with similar operation conditions to those employed in industry over the PSD is extremely important to improve the process control. There are few references in the literature about the PSD modeling in such polymerization systems, as well as systematic studies that correlate operational conditions with the particle size distribution (PSD) of a suspension polymerization, especially under conditions close to those found in industry as high holdup (volume fraction of monomer related to the total volume of the reaction medium). In this work, an experimental study about the effect of operational variables (stirrer speed, impeller position, holdup) over the final Particle Size Distribution (PSD) obtained by styrene suspension polymerization is carried out. Experimental data showed a significant effect of holdup over the PSD and that the decrease of holdup led to an increase in the particle size. Stirrer speed and impeller position did not present such significant effect. Nevertheless, it was observed a tendency of the PSD toward lower sizes when increasing these two variables. The effects of each variable over the average diameter of Sauter was verified throw the statistical analysis of experimental data. The statistical models obtained for each size range and for the average diameter of Sauter also presented a good reproducibility in relation to experimental data.
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Madeira, Fabiano Gomes [UNESP]. "Análise dinâmica de mecanismo articulado de suspensão com não-linearidade na rigidez devido à geometria e à excitação por desbalanceamento rotativo na condição não ideal." Universidade Estadual Paulista (UNESP), 2014. http://hdl.handle.net/11449/115917.
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000800632.pdf: 2649005 bytes, checksum: 0e6f6ee2cc449b2d9d89392080c49c79 (MD5)Essa dissertação trata da dinâmica de um sistema com não-linearidade na rigidez devido à geometria do mecanismo articulado de duas barras, identificado como NLGS ao longo do texto. Na Introdução do trabalho são mostrados exemplos de sistema com rigidez não-linear devido á geometria, destacando a aplicação desse tipo de sistema como isolador de vibração e também discute-se sobre a exposição humana à vibração como motivação e justificativa para o trabalho, ressaltando-se as frequências de ressonância das diversas partes do corpo humano. Na sequência faz-se a revisão bibliográfica sobre o assunto de vibrações para auxiliar na compreensão do trabalho. Após esses capítulos introdutórios é feita a apresentação e a modelagem matemática dos sistemas dinâmicos estudados: sistema NLGS ideal, sistema com rigidez não-linear e sistema não ideal. As equações de movimento são deduzidas pelo método de Lagrange. Após a dedução das equações de movimento faz-se a integração numérica utilizando o método de Runge-Kutta de quarta e quinta ordem e obtém-se a resposta dos sistemas (deslocamento, velocidade e aceleração). Como resultado da integração numérica são construídas algumas curvas, tais como: histórico de deslocamento, histórico de frequência, plano de fase, FFT, resposta em frequência e diagrama de bifurcação para ajudar na compreensão do comportamento dinâmico dos sistemas. Com base nos resultados obtidos percebe-se que os sistemas NLGS não ideal, NLGS ideal e com rigidez não linear apresentam um comportamento complexo devido à rigidez não-linear. Nesses três sistemas tem-se indicação de regime de movimento caótico inclusive. No sistema não ideal observa-se o efeito Sommerfeld, o qual deixa evidente a captura da rotação do motor pela frequência natural do sistema e o salto na curva da amplitude de deslocamento em função da frequência do motor. Fazendo um comparativo entre o...
This dissertation concerns with the dynamics of a system with nonlinearity in the stiffness due to geometry of a pivot mechanism of two bars, called NLGS in the text. In the Introduction are shown examples of system with nonlinear stiffness due to geometry, emphasizing the application of this kind of system as vibration isolator and is also discussed about the human exposure to vibration as motivation and justification in the research, emphaizing the different resonance frequencies of the human body. In the sequence is carried out the literature review about vibrations to help on understanding the research. After these introductory chapters is done the presentation and mathematical modeling of the studied dynamic systems: non-ideal NLGS system, ideal NLGS system, nonlinear stiffness system and non-ideal system. The equations of motion are deduced by Langrange's method. After the deduction of the equations of motion is carried out the numerical integration using the fourth and fifth order Runger-Kutta's method and it is gotten the response of the systems (displacement, velocity and acceleration). As result of the numerical integration some curves are plotted, such as: displacement history, frequency history, phase portrait, FFT, frequency response and bifurcation diagram to help on understanding the dynamic behavior of the systems. Based on the results is noticed that the following systems have a complex behavior due to nonlinear stiffness: non-ideal NLGS, ideal NLGS and nonlinear stiffness system. In these three systems there are indications of chaotic motion. In the non-ideal system the Sommerfeld effect is observed, evidencing the capture of the frequency of motor by the natural frequency of the system and the jump in the curve of frequency response. Comparing the non-ideal NLGS system and the non-ideal system conludes that the Sommerfeld effect is eliminated and the maximum amplitude of displacement is reduced by 27% in the non-ideal...
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Madeira, Fabiano Gomes. "Análise dinâmica de mecanismo articulado de suspensão com não-linearidade na rigidez devido à geometria e à excitação por desbalanceamento rotativo na condição não ideal /." Bauru, 2014. http://hdl.handle.net/11449/115917.
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Orientador: Bento Rodrigues de Pontes JuniorBanca: Marcio Antonio Bazani
Banca: Marcos Silveira
Resumo: Essa dissertação trata da dinâmica de um sistema com não-linearidade na rigidez devido à geometria do mecanismo articulado de duas barras, identificado como NLGS ao longo do texto. Na Introdução do trabalho são mostrados exemplos de sistema com rigidez não-linear devido á geometria, destacando a aplicação desse tipo de sistema como isolador de vibração e também discute-se sobre a exposição humana à vibração como motivação e justificativa para o trabalho, ressaltando-se as frequências de ressonância das diversas partes do corpo humano. Na sequência faz-se a revisão bibliográfica sobre o assunto de vibrações para auxiliar na compreensão do trabalho. Após esses capítulos introdutórios é feita a apresentação e a modelagem matemática dos sistemas dinâmicos estudados: sistema NLGS ideal, sistema com rigidez não-linear e sistema não ideal. As equações de movimento são deduzidas pelo método de Lagrange. Após a dedução das equações de movimento faz-se a integração numérica utilizando o método de Runge-Kutta de quarta e quinta ordem e obtém-se a resposta dos sistemas (deslocamento, velocidade e aceleração). Como resultado da integração numérica são construídas algumas curvas, tais como: histórico de deslocamento, histórico de frequência, plano de fase, FFT, resposta em frequência e diagrama de bifurcação para ajudar na compreensão do comportamento dinâmico dos sistemas. Com base nos resultados obtidos percebe-se que os sistemas NLGS não ideal, NLGS ideal e com rigidez não linear apresentam um comportamento complexo devido à rigidez não-linear. Nesses três sistemas tem-se indicação de regime de movimento caótico inclusive. No sistema não ideal observa-se o efeito Sommerfeld, o qual deixa evidente a captura da rotação do motor pela frequência natural do sistema e o salto na curva da amplitude de deslocamento em função da frequência do motor. Fazendo um comparativo entre o...
Abstract: This dissertation concerns with the dynamics of a system with nonlinearity in the stiffness due to geometry of a pivot mechanism of two bars, called NLGS in the text. In the Introduction are shown examples of system with nonlinear stiffness due to geometry, emphasizing the application of this kind of system as vibration isolator and is also discussed about the human exposure to vibration as motivation and justification in the research, emphaizing the different resonance frequencies of the human body. In the sequence is carried out the literature review about vibrations to help on understanding the research. After these introductory chapters is done the presentation and mathematical modeling of the studied dynamic systems: non-ideal NLGS system, ideal NLGS system, nonlinear stiffness system and non-ideal system. The equations of motion are deduced by Langrange's method. After the deduction of the equations of motion is carried out the numerical integration using the fourth and fifth order Runger-Kutta's method and it is gotten the response of the systems (displacement, velocity and acceleration). As result of the numerical integration some curves are plotted, such as: displacement history, frequency history, phase portrait, FFT, frequency response and bifurcation diagram to help on understanding the dynamic behavior of the systems. Based on the results is noticed that the following systems have a complex behavior due to nonlinear stiffness: non-ideal NLGS, ideal NLGS and nonlinear stiffness system. In these three systems there are indications of chaotic motion. In the non-ideal system the Sommerfeld effect is observed, evidencing the capture of the frequency of motor by the natural frequency of the system and the jump in the curve of frequency response. Comparing the non-ideal NLGS system and the non-ideal system conludes that the Sommerfeld effect is eliminated and the maximum amplitude of displacement is reduced by 27% in the non-ideal...
Mestre
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Yao, Chih-Hua, and 姚志樺. "Analysis of a Variable Geometry Suspension System." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/a36v4g.
Full textAbstract:
碩士國立臺北科技大學
車輛工程系所
93
This study establishes the mathematical models of quarter-car for vehicle straight running and the half-car for vehicle during cornering, and analyzes suspension link geometry relative to roll center and instantaneous center by using closure equation. Then installs a slider at the vehicle body-side connecting portion of the control arm, so that suspension geometry can be changed by sliding the slider. This paper is to suggest a variable geometry suspension in accordance with the running condition to reduce the variation of camber and the rolling moment of vehicle body, and then compare the analysis results with ADAMS/CAR software.
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Hsu, Wei-Feng, and 徐偉峰. "Design and Control of Variable Geometry Suspension Systems." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/5y28x6.
Full textAbstract:
博士國立臺北科技大學
機電科技研究所
101
In this paper, variable geometry suspension system (VGSS) is proposed to improve anti-roll performance of vehicle. The quarter-car and half-car geometry model of Double-Wishbone and Macpherson Strut suspension system are builded using Suspension Derivative Method, respectively. Force analysis of quarter-car suspension model also completed based on Equilibrium Method. Then, suspension characteristics parameters, such as toe angle, roll center location, wheel rate, and suspension roll rate, can be find out with geometry model and force analysis results. Subsequently, sliders are installed between upper and lower control arms of suspensions and vehicle body form VGSS models. ADAMS/Car is used to verify geometry model and force analysis under kinematic mode. Installation angle of slide shaft of the VGSS is optimized according to the cost function that composed of toe angle, roll center vertical location and slider axial force. VGSS roll model that consists of geometry model and roll model is derivatived for feedforward controller design. Parameters of the VGSS roll model are created as look-up tables to increase efficiency of controller operation. Proportional-Integral controller is combined with the feedforward controller for transient compensation. Finally, we also combine the software “Adams/Car” and “Matlab/Simulink” with the control system for the full-vehicle model verification. Energy consumption of proposed VGSS that is compared with vehicle equipped with active suspension system based on same anti-roll performance.
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Wu, Jan-Yi, and 吳展毅. "A Study of Trailing Arm Variable Geometry Suspension System." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/72uk4h.
Full textAbstract:
碩士國立臺北科技大學
車輛工程系所
96
This study establishes the mathematical models of Trailing Arm suspension system including quarter-car for vehicle straight running and half-car for vehicle during cornering, and analyzes how suspension link geometry position by using homogeneous transformation matrix. Then install a slider at the vehicle body-side connecting portion of trailing arm so that suspension geometry can be changed by sliding the slider. This trailing arm variable geometry suspension system can reduces body roll angle during cornering. Finally, in order to evaluate the safety and ride comfort. This study establishes the variable geometry suspension system in full vehicle model by using ADAMS/CAR software. And we also compare the roll characteristic of vehicle between traditional trailing arm suspension systems and variable geometry of trailing arm suspension systems. The result shows that the roll angle of vehicle attitude can be improved by using novel variable geometry suspension.
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Cheng, Wen-Lung, and 鄭文龍. "A Study of Variable Geometry of MacPherson Strut Suspension System." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/74z43n.
Full textAbstract:
碩士國立臺北科技大學
車輛工程系所
96
This study establishes the mathematical models of MacPherson suspension system including quarter-car for vehicle straight running and half-car for vehicle during cornering, and analyzes how suspension link geometry affects instantaneous center and roll center by using closure equation. Then install a slider at the vehicle body-side connecting portion of the top of the strut and portion of lower control arm so that suspension geometry can be changed by sliding the slider. This paper suggests a variable geometry suspension in accordance with the running condition to reduce the variation of camber angle and the rolling moment of the body. Finally, analyzes the transmission of force of variable geometry suspension and calculated the force to move the slider.
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Lin, Yu-Shih, and 林育詩. "Analysis and Control of Double Wishbone Variable Geometry Suspension System." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/ryd7xu.
Full textAbstract:
碩士國立臺北科技大學
車輛工程系所
96
In this paper, the enhancement of vehicle handling characteristics using variable geometry suspension is investigated. The variable roll center suspension concept in a double wishbone suspension is proposed. In order to achieve the controllable of roll center, a slider block is installed between upper control arm of suspension and vehicle body. Then, this paper also analyzes how suspension linkage geometry affects the toe angle by using closure equation. Thus, the most sensitive of toe angle is found. Therefore, in order to evaluate the handling performance, a full car model with variable geometry suspension is constructed using multi-body dynamic analysis software Adams. In addition, we use the fuzzy control to implement human’s heuristic knowledge and define the control input as the motion of the slider. Finally, we also combine the software “Adams/Car” and “Matlab/Simulink” with the fuzzy controller for the full-vehicle model analysis. The control input for fuzzy control of front suspension is the motion of the slider. Moreover, this paper also compares the power consumption between variable geometry suspension system and active suspension systems for roll control strategies. The result shows that the roll angle of vehicle attitude can be improved by using novel variable geometry suspension and active suspension control. Also the simulation demonstrates that the variable geometry principle will deliver cost effective performance in the future.
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Klaps, J., and Andrew J. Day. "Wheel movement during braking." 2002. http://hdl.handle.net/10454/886.
Full textAbstract:
YesAn experimental study of wheel movement arising from compliance in the front suspension and steering system of a passenger car during braking is presented. Using a Kinematic and Compliance (K&C) test rig, movement of the front wheels and the suspension sub-frame, together with corresponding changes in suspension / steering geometry under simulated braking conditions, were measured and compared with dynamic measurements of the centre points of the front wheels. The resulting knowledge of front wheel deflections has enabled the causes and effects of steering drift during braking to be better understood in the design of front suspension systems for vehicle stability.
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Yi-Chao, Li, and 黎益肇. "Investigation on aeroelastic behavior of suspension bridges with ertain simple geometric cross-sections." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/53045632482923523406.
Full textAbstract:
博士國立中興大學
土木工程學系
93
A numerical method is developed to predict the dynamic behavior of a suspension bridge under wind action in a two dimensional sense. In particular, the behavior of a vibrating deck with six simple geometric cross-section is examined. The simulations contain two parts of computations, which are performed alternatively during the calculation process. The solutions of the instantaneous flow field and the deck motions are considered the basis to analyze the problem of deck instability. Wind tunnel measurements are conducted in parallel to measure the response of a sectional bridge model. The vertical and torsional deflections of the model are measured under various wind speeds with several selected attack angles and eccentric mass. The results are used to confirm the accuracy of the numerical predictions. Results show that the numerical predictions of the structural response agree well with those from the experiments, indicating that the proposed method is capable of predicting the deck motion with good accuracy. Based on the time-series numerical results, finally, the interactive behavior of the vibrating deck is examined extensively.
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Ming-CheCheng and 鄭明哲. "The Effect of Geometric Parameters on the Performance of All-Terrain Vehicle Suspension Steering System." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/81146724949117475041.
Full textAbstract:
碩士國立成功大學
機械工程學系碩博士班
99
The main function of a suspension steering system is to afford vehicle weight, offer suitable directional control, and isolate the vehicle body from external forces and disturbance. A traditional suspension system is a passive suspension system. It consists of a linkage mechanism and a mechanical spring. And, geometrical structure is a crucial factor which determines the performance. The purpose of this work is to analyze an existing design namely ATV 500 manufactured by KYMCO Company. Firstly the background and relative parameters of this ATV is introduced briefly. Then a kinematic and simplified model analysis for the suspension steering system is derived along with the performance index. For improving the performance, the sensitivity analysis and optimization design are discussed based on the result of kinematic analysis. In addition, ADAMS software is used and verified that the derived kinematic analysis is feasible. The programming interface of kinematic analysis and simplified model for users is further provided. Finally, the optimization design based on the objective function of minimum change of kinematic parameters is performed. And, the result shows that the ride and handling performance are improved.
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Martins, Marco António Figueiredo. "Veículo híbrido de transporte pessoal." Master's thesis, 2018. http://hdl.handle.net/10400.6/10007.
Full textAbstract:
Um velomobile corresponde a um veículo de propulsão humana com carenagem parcial ou completa e uma posição confortável de condução reclinada ou semi-reclinada. Esta definição abrange os carros a pedais que surgiram inicialmente como uma alternativa mais económica ao automóvel. O primeiro carro a pedal e com carenagem bem documentado foi o Velocar de Charles Mochet, utilizado como veículo de transporte próprio e testado em corridas de bicicletas onde a sua instabilidade em curva a velocidades mais elevadas facilmente atingíveis provou ser uma desvantagem. Para colmatar este facto, foi desenvolvido por Mochet um veículo de duas rodas com uma posição reclinada de condução designado de Velo Velocar (atualmente conhecido como bicicleta reclinada). Ambos os veículos, Velocar e bicicleta reclinada, estão hoje associados ao termo velomobile moderno projetado para ser um veículo prático e seguro. Como exemplo de velomobile moderno temos o Allweder, cujo princípio de construção serviu como base de inspiração para o desenvolvimento de outros velomobiles cuja velocidade se tornou no principal foco de produção, sacrificando características funcionais importantes como a estabilidade em curva, capacidade de travagem, tração na roda traseira, acesso ao veículo, visibilidade e manobrabilidade. Neste sentido, surge a necessidade de projetar um velomobile com a capacidade de colmatar estas desvantagens. Os veículos Tilting three-wheeler representam o conceito mais promissor, pois possuem um mecanismo que lhes confere a capacidade de inclinação e, por conseguinte, maior estabilidade em curva a velocidades mais elevadas. No entanto, a baixas velocidades estes veículos tornam-se instáveis e no momento da sua imobilização, o condutor é obrigado a colocar os pés no chão. Desta forma, um velomobile com um sistema que o permita inclinar em curva independentemente da velocidade a que circule, torna-se uma excelente solução alternativa aos problemas de instabilidade em curva. Para desenvolver um velomobile deste tipo, foram implementados um conjunto de especificações tais como: uma configuração Tadpole, uma posição de condução reclinada, um sistema de direção do tipo Under seat steering, um sistema de suspensão de duplo triângulo onde foi adaptado um mecanismo em paralelogramo que permite a inclinação do veículo em curva, uma carenagem envolvente, um motor elétrico auxiliar, um sistema de transmissão por corrente e dois sistemas de travagem hidráulica independentes.
O veículo desenvolvido de acordo com os parâmetros selecionados parece ser o ideal para colmatar os problemas de insegurança gerados por um típico velomobile.A velomobile corresponds to a human-propelled vehicle with partial or complete fairing and a comfortable recumbent or semi-recumbent driving. This definition covers pedal cars that initially appeared as a more economical alternative to the car. The first pedal car well-documented with a fairing was the Velocar of Charles Mochet, used as own transport vehicle and tested on bike races where its instability in curve at higher speeds easily attainable proved to be a disadvantage. To overcome this fact, was developed by Mochet a two-wheeled vehicle with a reclining driving position called Velo Velocar (currently known as recumbent bike). Both vehicles, Velocar and recumbent bike, are today associated to the modern velomobile term, designed to be a pratical and safety vehicle. As an example of modern velomobile we have the Allweder whose construction principle served as the inspiration base for the development of other Velomobiles whose speed has become the main focus of production, sacrificing important functional characteristics as curve stability, braking capacity, rear wheel drive, vehicle access, visibility and maneuverability. In this sense arises the need to design a velomobile with the ability to overcome these disadvantages. The Tilting three-wheeler vehicles represents the most promising concept, because they have a mechanism that gives them a tilting capacity in curvature more steadily at high speeds. However, at low speeds these vehicles become unstable and at the moment of their immobilization, the driver is required to put his feet on the ground. In this way, a velomobile with a system that allows it to tilt in a bend regardless of the speed at which it circulates, it becomes an excellent alternative solution to the instability problems. To develop a velomobile of this type, a set of specifications such as a Tadpole configuration, a reclined driving position, an under-seat steering system, a double triangle suspension system where it was adapted a parallelogram mechanism that will allow to tilt in curvature, a wraparound fairing, an auxiliary electric motor, a chain drive system and two independent hydraulic braking systems. The vehicle developed according to the selected parameters seems to be the ideal solution to overcome the insecurity problems generated by a typical velomobile.