Distribution of human-seat interface pressure on a soft automotive seat under vertical vibration

Distribution of contact pressure and forces between the seated human subjec ts and a visco-elastic seat is experimentally investigated under vertical v ibration. The dynamic pressure on the elastic seat is measured under sinuso idal vertical vibration of different magnitudes in the 1-10 Hz frequency ra nge, using a flexible grid of pressure sensors. The human-seat interface pr essure data acquired with a total of six subjects is analyzed to illustrate the influence of magnitude and frequency of vibration excitations on the m aximum ischium pressure, effective contact area and contact force distribut ion. The results are discussed to illustrate the influence of seated postur e and the subject build on the contact force and area. Alternately, the con tour maps of static pressure distribution, and time histories of the ischiu m pressure and the effective contact area measured under vibration are comp ared with those determined while using a rigid seat. The results show that the maximum variations in the ischium pressure and the effective contact ar ea on a soft seat occur near the resonant frequency of the coupled human-se at system (2.5-3.0 Hz). The maximum ischium pressure and effective contact area on a soft seat tend to increase considerably with increase in the magn itude of vibration excitation.