Investigation of the Effects of Temperature Variations on the Magnetorheological Damper Behaviour

Magnetorheological (MR) dampers have received a great deal of attention due to their being a potential technology to conduct semi-active vibration control and it has become vitally important to describe the dynamic responses of these devices in an effective manner in order to develop successful control algorithms. To this end, a considerable effort has been devoted in the literature to study the factors affecting the dynamic behaviour of MR dampers. And, so far, excitation displacement, velocity, and current have been shown to be the primary factors. However, MR dampers can experience large variations in temperature due to self-heating of the damper as well as heat addition to the MR fluid because of the magnetic coil on the piston head. The change in fluid temperature may result in a decay in fluid viscosity and thus, a decrease in the post-yield damping of the damper. Also, heated gas in the accumulator may yield an additional increase in the stiffness of the damper. To study these effects, a low-force and a low-stroke MR damper was built and tested at the Applied Fluid Mechanics Laboratory of University of Sakarya. And, it has been observed that temperature was at least as important as velocity on the damper behaviour.