A low-order, lumped parameter model is proposed to describe the vertic
al vibration compliance of an automotive seat. The model includes nonl
inear stiffness and damping effects that mimic the properties exhibite
d by open cell foams that are commonly used in the construction of an
automotive seat cushion. A shaped sandbag was positioned on a seat cus
hion and vibrated to obtain test data. White noise acceleration with a
mplitude ranging from 0.05 g rms to 0.45 g rms in increments of 0.05 g
rms was used to excite the seat track. A luxury car seat and a sports
car seat were tested and a nonlinear seat model was identified that p
redicts the actual test data with fidelity. The paper demonstrates tha
t once a family of model parameters is identified for a particular sea
t, then the model can be used for a wide spectrum of seat track inputs
. Additional experiments also verified that when the sandbag mass was
increased by as much as 50%, the predicted response using the proposed
model was in agreement with the measured response. Finally, the paper
reports the result of an experiment using a human subject on a seat c
ushion. A simulation using the new cushion model and an ISO vibration
model of a seated human produced response data that was very similar t
o the actual test data.