A study on the piston shape of the viscous damper to reduce the storage modulus

Abstract

The viscous fluid damper using silicon oil is widely used for vibration isolation in heavy industrial equipment as well as seismic isolation of building structures. It is well known that the viscous damper exhibit viscoelastic behavior, i.e. both elastic and viscous behavior. The elastic behavior of the viscous damper can be described as the storage stiffness which is increased as the excitation frequency increases. The vibration isolation, therefore, can be often failed because of the increased storage stiffness. For effective vibration isolation, damper should have high damping and low storage stiffness. In this paper, the effect of the piston shape is studied to reduce the increment of the storage stiffness. Toward this end, the shape of bottom surface of the piston has been changed to the cone type. The experimental results show that the modified piston shape can provide good performance, and the result may be used for the isolator design engineers in industry. Copyright © (2011) by the International Institute of Acoustics & Vibration.