Analysis Of Vehicle Dynamics Random Response To Road Irregularity Inputs

In this thesis, the full car model with eight degrees of freedom and four-wheeled random road displacement inputs was established and the differential equation to describe the vehicle random vibration was deduced.The method of frequency domain is used to research the random responses of linear system on vehicle dynamics. The results display that the resonance of the frequency of prompting and natural frequency of car parts produces the peak value of accelerated power spectral density for car, vibrational energy mainly store in the low frequency, low frequency is an oscillatory sensitive frequency of vibration.For nonlinear damping of vibration isolator, the random responses of nonlinear system on vehicle dynamics are numerically simulated. The results display that with increase on speed, the car vibration turn worse, that the simulations agree with the test results, that the calculation of the random responses of nonlinear system on vehicle dynamics by equivalent damp linearization method is more accurate than one by statistic linearization method.Study on change of parameter, the random responses of vehicle dynamics is numerically simulated. It is the conclusion that change of parameter has a great contribution to the random vibration of vehicle dynamics, that this problem can be solved by the rational change of parameter.In the paper, the model of vehicle dynamics and the method and programmer of vibration can predict the safety and the criteria of the ride comfort, and provide research basis for the stability of vehicle and its impact factor.