Investigation On Nonlinear Dynamical Behavior In Automobile Air Spring Suspension System

The automobile suspension system plays an important role in automobile riding comfortability, operation stability and brake performance. It is always looked upon as linear systems in traditional auotomobile design theory. However, there are strongly nonlinear features in air spring suspension due to the material nonlinearity, geometry nonlinearity and contact nonlinearity, which may have important effects on the riding comfortability and other performances. In this dissertation, the nonlinear dynamic study method is introduced to research the dynamical analysis and design theory of automobile suspension system.Based on membrane-typed air spring, the dynamical model of air spring suspension is established through theoretical analysis and test measurement. Then the dynamical solution for air spring suspension is obtained by nonlinear dynamical method, and its dynamic behavior is analyzed under determinate excitation, that is to say, the analytical solution of single-degree-freedom air spring suspension under single-frequency and double-frequency excitation is obtained and the chaotic phenomenon is studied too. Furthermore, the dynamic behavior is analyzed in two-degrees-freedom air spring suspension, and the approximate analytical solution for internal resonance and non-internal resonance and other nonlinear dynamical behaviour is investigated.The contribution of nonlinear feature in air spring suspension to riding comfortability, operation stability and brake performance is also studied, where the nonlinear dynamic study method is joined to vechicle dynamic study. It is shown that the air spring suspension has more advantages than the helix spring suspension. The research on optimal control provides theoretical basis for parameter optimization of suspension.The innovations in this dissertation are focused on confirming the dynamical model of membrane-typed air spring suspension, analyzing the dynamical behavior of air spring suspension under single-frequency and double-frequency excitation, studying the effects of the possible chaotic motions on vechicle performance, researching the approximately analytical solution for internal resonance and non-internal resonance of two-degrees freedom air spring suspension system, and combining nonlinear dynamic method with vechicle suspension dynamics.