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Authors
Abstract(s)
O principal objetivo desta tese é comparar o comportamento estático e dinâmico
de dois tipos de suspensão aplicáveis a um veículo Formula Student. Estes dois tipos de
suspensão são o push-rod e o pull-rod, que irão ser analisados detalhadamente para
explicar as suas principais vantagens e desvantagens. De forma a enquadrar a temática a
ser estudada, serão apresentados os conceitos básicos dos automóveis e a sua evolução na
história da Fórmula 1, com o foco nos dois dos tipos de suspensão referidos
anteriormente.
No presente trabalho, efetuaram-se dois tipos de análises para responder ao
objetivo proposto. Essas análises consistem na análise estática e dinâmica dos dois
sistemas em causa. Relativamente à primeira, ao se realizar as análises estáticas dos
sistemas de suspensão, push-rod e o pull-rod, verificou-se que ambos são equivalentes
em termos de desempenho estático, com perfis de tensão e de deformação semelhantes.
Além disto, constatou-se que nos dois sistemas as cargas estáticas transmitidas ao chassis
e aos componentes da suspensão apresentam valores idênticos. No entanto, no sistema
pull-rod há uma ligeira dependência não linear da carga, na posição vertical da roda.
A respeito das análises dinâmicas às duas suspensões conseguiu-se perceber, pelas
matrizes de rigidez (K) e de amortecimento (C), que o sistema push-rod tem um grau de
liberdade igual a zero. O mesmo não acontece com o sistema pull-rod. Relativamente às
frequências naturais, os valores são quase idênticos.
Após a realização das análises, estática e dinâmica, foi possível verificar que os
dois sistemas são muito semelhantes. Contudo, existem algumas diferenças como:
dependência não linear da carga da suspensão na posição vertical da roda no sistema pullrod,
independência do movimento relativamente a uma direção no sistema push-rod, o
sistema push-rod ter uma melhor ajustabilidade dos parâmetros da suspensão e por
último, nas análises estáticas detetou-se algumas diferenças na propagação das forças
pelos dois sistemas. Por fim, concluiu-se que a melhor opção para o sistema de suspensão
do protótipo Formula Student é que o sistema de push-rod é o melhor para a dianteira do
veículo, mas para a traseira o melhor sistema é o pull-rod.
The main goal of this thesis is to compare the static and dynamic behavior of two types of suspension applicable to a Formula Student vehicle. The two suspension types - push-rod and pull-rod - are analyzed in detail to explain their main advantages and disadvantages. In order to frame the theme, the basic concepts of automobiles and their evolution in the history of Formula 1 will be presented, focusing on the two types of suspension mentioned above. In the present work, two types of analysis were executed to answer the objective. These analysis consist of the static and dynamic analysis of the two systems concerned. Regarding the first, static analyzes of the suspension, push-rod and pull-rod systems were found to be equivalent in terms of static performance, with similar stress and strain profiles. In addition, it was found that in both systems the static loads transmitted to the chassis and the components of the suspension have identical values. However, in the pullrod system there is a slight nonlinear dependence of the load, in the vertical position of the wheel. In respect of the dynamic analysis of the two suspensions the rigidity (K) and damping (C) matrices show that the push-rod system has a degree of freedom equal to zero. The same does not happen with the pull-rod system. Relative to natural frequencies, the values are almost identical. After the static and dynamic analyzes, it was possible to verify that the two systems are very similar. However, there are some differences such as: non-linear dependence of the load of the suspension in the vertical position of the wheel in the pullrod system, independence of movement relative to a direction in the push-rod system, the push-rod system has a better adjustability of the suspension parameters, and finally, in the static analyzes some differences in the propagation of the forces by the two systems were detected. Finally, it was concluded that the best option for the suspension system to the Formula Student prototype is the push-rod system for the front of the vehicle, but for the rear the best system is the pull-rod.
The main goal of this thesis is to compare the static and dynamic behavior of two types of suspension applicable to a Formula Student vehicle. The two suspension types - push-rod and pull-rod - are analyzed in detail to explain their main advantages and disadvantages. In order to frame the theme, the basic concepts of automobiles and their evolution in the history of Formula 1 will be presented, focusing on the two types of suspension mentioned above. In the present work, two types of analysis were executed to answer the objective. These analysis consist of the static and dynamic analysis of the two systems concerned. Regarding the first, static analyzes of the suspension, push-rod and pull-rod systems were found to be equivalent in terms of static performance, with similar stress and strain profiles. In addition, it was found that in both systems the static loads transmitted to the chassis and the components of the suspension have identical values. However, in the pullrod system there is a slight nonlinear dependence of the load, in the vertical position of the wheel. In respect of the dynamic analysis of the two suspensions the rigidity (K) and damping (C) matrices show that the push-rod system has a degree of freedom equal to zero. The same does not happen with the pull-rod system. Relative to natural frequencies, the values are almost identical. After the static and dynamic analyzes, it was possible to verify that the two systems are very similar. However, there are some differences such as: non-linear dependence of the load of the suspension in the vertical position of the wheel in the pullrod system, independence of movement relative to a direction in the push-rod system, the push-rod system has a better adjustability of the suspension parameters, and finally, in the static analyzes some differences in the propagation of the forces by the two systems were detected. Finally, it was concluded that the best option for the suspension system to the Formula Student prototype is the push-rod system for the front of the vehicle, but for the rear the best system is the pull-rod.
Description
Trabalho final de mestrado para obtenção do grau de mestre em Engenharia Mecânica
Keywords
Análise estática Static analysis Análise vibracional Vibrational analysis Suspensão Push-rod Push-rod Suspension Suspensão Pull-rod Pull-rod Suspension
Citation
FERREIRA, Pedro Miguel Farinha - Estudo comparativo de dois tipos de sistemas de suspensão de um carro Fórmula Student. Lisboa: Instituto Superior de Engenharia de Lisboa, 2019. Dissertação de mestrado.
Publisher
Instituto Superior de Engenharia de Lisboa