Abstract
For the passive isolation systems, a friction damper is often used because it is simple, inexpensive and reliable. However, the ordinary friction damper of constant friction force has performance limitations, because the isolation characteristic declines when the friction force is large, while resonance peak becomes large when the friction force is small. Furthermore, the displacement remains apart from the equilibrium position after the disturbance disappears. In order to overcome the above drawbacks of the ordinary friction damper, a new type of friction damper is proposed in our previous paper. This is achieved by use of an inclined lever, which contacts the cylindrical block by means of a rotational spring. When the cylindrical block moves, the angle of lever inclination varies, causing the normal and frictional forces at the contact surface to vary according to the displacement of the cylindrical block. However, sprag-slip vibration occurred in the experiments. This paper investigates the cause of the vibration and the design to prevent it.
