Non-linear analysis of a quarter-car model with stroke-dependent twin-tube shock absorber

Abstract

Abstract The work presents results of the analysis of a quarter-car model with a modified twin-tube hydraulic shock absorber. In comparison with a classical damper, this shock absorber possesses an additional double-chamber cylinder. The flow of oil into these chambers is controlled by relative displacement of the auxiliary piston and by pressure difference in the adjacent chambers. The introduced nonlinear spring element – bumper – protects the shock absorber against damage in the case of large amplitudes of excitations. Performance efficiency of the shock absorber model within the range of both large amplitudes and high excitation frequencies ensures that the change of the oil bulk modulus resulting from a change in pressure is accounted for. The introduction of additional chambers into the shock absorber leads to a change in the characteristics of the damping force. Within the range of small amplitudes and high frequencies the system acts like a shock absorber with a soft characteristic, which improves the driving comfort. In resonance ranges the increase in the damping force ensures higher driving safety. The analysis of the system response to the harmonic excitation of variable frequency and amplitude as well as to the random excitation permits to examine the impact of excitation parameters and construction parameters on the indicators characterizing the driving comfort and safety. The results of numerical simulations are illustrated with the graphs of time histories, spectral analyses, characteristics of the damping force, and others, illustrating the processes of controlling oil flow.