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

Abstract

Distribution of contact pressure and forces between the seated human subjects and a visco-elastic seat is experimentally investigated under vertical vibration. The dynamic pressure on the elastic seat is measured under sinusoidal vertical vibration of different magnitudes in the 1–10 Hz frequency range, using a flexible grid of pressure sensors. The human–seat interface pressure data acquired with a total of six subjects is analyzed to illustrate the influence of magnitude and frequency of vibration excitations on the maximum ischium pressure, effective contact area and contact force distribution. The results are discussed to illustrate the influence of seated posture and the subject build on the contact force and area. Alternately, the contour maps of static pressure distribution, and time histories of the ischium pressure and the effective contact area measured under vibration are compared with those determined while using a rigid seat. The results show that the maximum variations in the ischium pressure and the effective contact area on a soft seat occur near the resonant frequency of the coupled human–seat 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 magnitude of vibration excitation. Relevance to industry Pressure distribution at the human–seat interface has been found to be an important factor affecting the seating comfort and possibly the work efficiency of various workers. The study of human–seat interface pressure distribution under vibration is of relevance to seated vehicle drivers who are regularly exposed to vibration. The results reported in this paper may find some use for designing seat cushions with enhanced postural support abilities while taking account of the dynamic pressure distribution under vehicular vibration.