A quarter-car model comprising geometrical nonlinearities and asymmetric dampers
Julio Cesar de Moraes Fernandes1; Marcos Silveira1; Bento Rodrigues de Pontes Jr.1; José Manoel Balthazar1
1 Department of Mechanical Engineering - UNESP - Bauru/SP, Brazil
doi:10.20906/CPS/COB-2015-0127
Resumo
The objective of this work is to study the dynamical behavior of vehicle suspension systems employing asymmetrical viscous damping, with a focus on improving passenger comfort, considering geometric non-linearities which are present in the system. Previous studies have shown that the use of asymmetrical dampers in these types of systems can be advantageous with regard to handling and comfort of the passengers. Two configurations, one with symmetrical viscous damping and another with asymmetrical viscous damping are presented and compared. The simulations are performed using a quarter-car model under harmonic excitation. The geometric configuration of a suspension system is taken into account in modeling the damping force and spring force, to include geometrical non-linearities in the model. Mathematical models of the described suspension systems are analyzed by numerical simulation, and the analyses are done using methods in nonlinear dynamics. For this analysis, the values of the damping coefficient for the compression and extension of the damper were varied, establishing an asymmetry ratio. Through modeling and computer simulations in this study, the choice of the asymmetry ratio diminishes the effects that the uneven pavement causes on the displacement and acceleration of the sprung mass, improving the comfort for the passengers.
Palavras-chave: vehicle dynamics; asymmetrical damper; harmonic excitation; geometrical nonlinearities