Stiffness and Damping Coefficients of Liquid Crystal Film Under Electric Field

This paper describes the stiffness and damping properties of liquid crystal film under electric field in a slide bearing. Liquid crystal is known as a homogeneous organic liquid characterized by the long-range order of its molecular orientation. When an electric field is applied to a liquid crystal, the orientational order of molecules becomes parallel to the applied electric field, which causes apparent viscosity variation. Applying liquid crystal as lubricant, a controllable bearing system may be realized by the external electric signal. In this paper, a controllable sliding bearing system in which liquid crystal was applied as lubricant was constructed and its controllability and dynamic properties were studied experimentally. In the present bearing system, a sinusoidal load was applied to the bearing pad by a magnetic exciter and the equivalent spring and damping constant were identified under various electric field, sliding velocity and film thickness. The results show that the applied electric field strength has little effects on the equivalent spring constant of the liquid crystal film, whereas it has large effects on the damping properties.