Polyurethane Foam Performances’ Influence on Body Pressure Distribution on an Automotive Seat

From the microstructure point of view, the relationship of car seat comforts, including the static and dynamic comfort, and the polyurethane foam performance of its cushion has been analyzed. In this paper, polyurethane cushion performances associated with the seat static comfort have been mainly discussed. And their quantizing relation is obtained. How to apply the pressure gradient, one of body pressure distribution parameters, to optimize automobile seat comfort has been analyzed in detail. The findings suggest maximum and mean values of body pressures increase by 0.09 KPa and 0.04 KPa with the cushion foam hardness (P_h) increasing 1 KPa, respectively. The pressure gradient is little dependent on the cushion foam hardness within the range of P_h=4 ~ 5 KPa. Furthermore, the foam thickness under the hip should be greater 80 mm in order to reduce subcutaneous stresses under conditions of P_h= 6.2 KPa.