Nonlinear dynamic characteristics and parameters identification method for hydraulic engine mount

The dynamic characteristics of hydraulic engine mounts(HEMs) with different lengths of inertia tracks are studied experimentally.It is revealed for the first time that the frequency-dependent dynamic characteristics of the HEM with inertia track under different excitation amplitudes have fixed points.Then a nonlinear lumped parameter model(LPM) for HEMs with inertia track is developed based on the theory of engineering hydromechanics,in which the parameters are asso-ciated with the geometry of hydraulic mechanisms,and an ana-lytical solution is obtained,in which the fixed point on the dy-namic stiffness in-phase as a function of excitation frequency and amplitude is discovered theoretically.The reliable consis-tency between analytical and experimental results shows the validity of the LPM and the correctness of the analytical con-clusions.Based on the fact that the analytical conclusions matches well with the experimental ones and according to the phenomena of the fixed point and the constant value at higher bands of the dynamic stiffness in-phase,a new parameter iden-tification method is presented,which is clear in theory and is time-and cost-saving,and the identified results are reliable.