High-frequency model of monotube shock absorbers

It has been long recognized that the inertia and compressibility of the fluid have an impact on the dynamic behaviour of semi-active monotube shock absorbers utilizing so-called smart ER/MR fluids at high frequencies of the system operation. Previous studies which dealt with analytical state-space & CFD models of the magnetorheological shock absorber in a monotube configuration indicated that any conventional analytical model is lightly damped and not suitable for dynamic studies above 100-150 Hz. Therefore, in the present paper the author illustrates an analytical model of a monotube shock absorber that is suitable for high-frequency studies. In particular, the study presents a comparison between the CFD results and the new model. Finally, the shock absorber characteristics in the form of Bode plots of amplitude and frequency are presented within a prescribed range of frequencies.