Mahya Boreiry, - Department of Automotive Engineering, Iran University of Science and Technology, Tehran. Iran
Salman Ebrahimi-Nejad - Department of Automotive Engineering, Iran University of Science and Technology, Tehran. Iran
Javad Marzbanrad - Department of Automotive Engineering, Iran University of Science and Technology, Tehran. Iran

In the present study the chaotic behaviour of nonlinear full vehicle model with seven degrees of freedom using magnetorheological (MR) damper is investigated. The disturbance applied from the road to the vehicle suspension system is assumed to be sinusoidal with time delay between front and rear axles as well as left and right tires. By means of nonlinear systems stability theory, the probability of occurrence of chaotic behavior is demonstrated. The MR damper injected to motion equations based on modified Bouc-Wen. The motion equations solved using 4th order Runge-Kutta method. Poincare maps and bifurcation diagrams obtained through numerical calculations are first validated with those presented in the literature, which approves the accuracy of the presented model and solution procedure. The results are presented for the vehicle with MR dampers and the findings on the influence of MR damper are discussed. The sensitivity analysis is performed using bifurcation diagrams to show the effect of various road excitation parameters on system stability. Numerical results presented in this study can be used in the dynamic design of vehicles and can serve as benchmark for future studies

Chaos; Magneto-rheological (MR) damper; Nonlinear full-vehicle model; Sensitivity analysis