Nonlinear seat cushion and human body model

Abstract

This paper presents the nonlinear characteristics of typical automotive seat cushion structure. As discussed in an earlier paper by the authors (Pang et al., 2004), the experimental transfer functions between the seat butt and the seat track vary with changes in the excitation levels. Both the magnitudes and frequencies of the transfer functions shift to smaller values as the excitation increases. Two nonlinear models are established to reveal this nonlinear phenomenon in the automotive seats. One of the models is combined with the ISO linear human body model to form a nonlinear seat-human body model. The simulated transfer functions between the head and the seat track, between the body and the seat track, and between the seat butt and the seat track are correlated with experimental results. The models proposed here are intended to help engineers optimise the ride quality of the vehicle.