The effect of vibration characteristics of an automotive seating system on ride comfort – A finite element study

Abstract

The Automotive Seating System (ASS) is an important sub-system in a car for increasing the ride comfort of driver/occupant and hence the need for a systematic study on the vibration characteristics of ASS is of importance. The present study finds out the vibration characteristics of four models of automotive seating system, with and without dummy mass using finite element analysis. The vibration mode shapes such as lateral, fore-aft and twisting of automotive seating system found in the frequency range 0-80 Hz for the four models of automotive seating system and correlated with experimental results found in the literature. The natural frequency of the seat with dummy mass was found to be in the human discomfort zone of the spinal column (10–12 Hz) and abdomen (4–8 Hz). The vibration transfer to occupant body was studied at 11 positions, with unit acceleration given at four mounting locations of automotive seating system in three directions separately. The vibration transmissibility was found to be higher than one in seat backrest. The random vibration analysis was carried out to identify the acceleration level of automotive seating system, subjected to smooth and rough road excitations. In the case of rough road random excitations, the results of root mean square acceleration values in automotive seating system show that the driver/passenger feels “fairly comfortable”. This study emphasizes the importance of the ride comfort of driver/occupant. To enhance the ride comfort, the stiffness of seat structure has to be modified and suspension system has to be introduced.