Fluid Dynamics and Behavior of Nonlinear Viscous Fluid Dampers

Abstract

Fluid dynamics in viscous fluid dampers with annular orifices was analyzed by solving the Navier–Stokes equations. The shear-thinning effect and viscoelastic behavior of silicone oil, which is often used in a viscous fluid damper, were both considered. When the solutions were compared to experimental data, it was found that both the nonlinear viscous and the restoring-force behaviors of viscous dampers can be captured. To verify the effects of fluid inertia, finite-element analysis of the fluid dynamics in the damper tested was also performed, assuming the damper was filled with a Newtonian fluid. It was found that the inertial force is not important in an annular-orificed damper moving at 10Hz. The effect of fluid compression in a fluid damper was also discussed. The proposed equations were used to calculate the restoring forces in the annular-orificed damper. It was found that the results give a close restoring force-displacement relationship as the one given by FEMA 273.