Optimization of the static properties of seat foam to improve the seating comfort

Abstract

In this study, we suggest an optimization process for the characteristics of seat foam to improve the seating comfort. The items selected for the optimization of the characteristics of seat foam are the initial comfort, the static comfort and the transient comfort. The evaluation items selected for optimization are the modulus irregularity factor, the amount of compression and the amount of sagging. The properties of the foam material which are the object of the optimization are simulated using fitting equations. The variables which have important influences on the expression for the foam characteristics are selected as the factors for the optimization. Additionally, the normalized relaxation modulus, which describes the time-dependent deterioration in the foam characteristics, is selected as one of the key factors. To design the experiments, a central composite design is selected from among the response surface methods. A second-order regression model is used to create the response surfaces, and the mechanical characteristics of the foam materials that influence the initial comfort, the static comfort and the transient comfort are evaluated by analysis of the response surfaces. It is possible to produce data on the foam characteristics which satisfy all optimization items by optimum designs.