Experimental and Numerical Investigation of Body-Cushion Interface Pressure Distribution

To design high-functional cushions, it is necessary to elucidate how the body-cushion interface pressure distribution is affected by the specifications of the body as well as that of the cushion. We have experimentally and numerically investigated the pressure distributions for various body-cushion pairs. The experimental results, obtained for relatively simple cushions and bodies, show that the space mean pressure is proportional to the body mass and inversely proportional to the body-cushion contact area. Also, the maximum pressure observed at the body prominence proved to increase with the body surface curvature. Furthermore, it is confirmed that the use of an air-cell cushion can flatten the pressure profile, if the internal air pressure is adjusted appropriately, while the pressure profile has sharp peaks at the body prominences when a polyurethane cushion is used, especially when the body curvature is large. The numerical simulations, in which basic specifications of body and cushion were taken into account, produced pressure distributions that qualitatively agreed with the measurements. The results will contribute to establish the design of optimal cushions which realize desired pressure distributions with consideration of the body specifications.