Adjustable fluid damper with SMA actuators

Abstract

The passive fluid damper is one of most widely used control devices for mitigating thevibration of stay cables in a cable-stayed bridge in practice. However, each stay cablefeatures unique dynamic characteristics and requires a specific damper to achieve the bestvibration mitigation, which engenders much trouble in the manufacture, implementationand maintenance of dampers. In this study, a novel adjustable fluid damper with shapememory alloy (SMA) actuators was developed. Instead of the fixed number of orifices inthe piston head of a common fluid damper, SMA actuators were installed insidethe piston head to control the number of orifices so as to change the damperparameters for the best control of a group of stay cables. The principle and designissues of the adjustable fluid damper are introduced. An adjustable fluid damper,which has ten orifices in the piston head, eight of them being controllable forachieving changes in damping at nine levels, was designed and manufactured. Theperformance tests of the dampers were carried out within a range of frequencies andamplitudes and for a number of open orifices and different sizes of orifice. Theexperimental results provide a data base for the Maxwell model of the damper and showthat such a damper can provide a wide range of forces and energy dissipationcapacity.