A novel nonlinear vibration isolator as vehicle seat suspension for enhanced ride comfort

In this paper, a newly proposed nonlinear isolator is employed as a seat suspension to mitigate the transmission of low-frequency vehicle-induced vibrations to the human body. The isolator, named as the high-static-low-dynamic stiffness sliding mass inertia (HSLDS-SMI) isolator, incorporates high-static-low-dynamic stiffness (HSLDS) and two specifically designed sliding mass inertia (SMI) components. A model of 8 degrees of freedom is then developed for the coupled system of a quarter car, seat and human body with the new seat suspension by means of the Lagrange principle. A parametric investigation focusing on force characteristics and equivalent mass is conducted to clarify the contribution of the HSLDS and SMI. To evaluate the isolation performance of the new seat suspension, different performance indices, including the biodynamic responses of different human body parts, spinal injury risk factor and vibration dose value (VDV), are evaluated for the vehicle subjected to harmonic, shock and random excitations and compared with those of two counterpart seat suspensions. The simulation results suggest that the new seat suspension provides better performance and significantly improves vehicle ride comfort while ensuring the seat stroke within acceptable limits.