Control of mechanical properties by a new cushion using an urethan with in an air cell

(2nd report: Influence on mechanical properties of a cushion by the load)

Abstract

This paper describes a new cushion using a urethane within an air cell (UA cell). In order to reduce vibration of occupants, we propose the UA cell. The purpose of this paper is to clarify the mechanical characteristics of the UA cell when the air pressure and loads changes. In this study, the UA cell consisted of a liner polyethylene and the urethane is designed. The mechanical characteristics of the UA cell are examined by a measurement using a vibration exciter. From these results, the thickness of UA cell is changed when air pressure and loads changes. Resonance frequencies and spring constant of the UA cell are changed when the thickness of UA cell is changed. Also, the spring constants, damping ratio and viscous damping coefficients of the UA cells and the spring constants, damping ratio and viscous damping coefficients of the air cells are similar when the thickness of UA cells exceed the thickness of the urethane. If thickness of the UA cells are the same, it was shown that the vibration characteristics of the UA cells are not changed when the load is changed. Therefore, the vibration characteristics of the UA cell can be controlled by the thickness of the UA cells controlled.