Title of Dissertation: DEVELOPMENT OF MAGNETORHEOLOGICAL FLUID ELASTOMERIC DAMPERS FOR HELICOPTER STABILITY AUGMENTATION Wei Hu, Doctor of Philosophy, 2005 Dissertation directed by: Professor Norman M. Wereley Department of Aerospace Engineering Conventional lag dampers use passive materials, such as elastomers, to dissipate energy and provide stiffness, but their damping and stiffness levels d...

The present study focusses on the damping force control of shear mode magnetorheological (MR) damper for seismic mitigations. Therefore, the semi-active MR damper which can control the vibration is analyzed both experimentally and numerically. Carbonyl iron is used as the magnetic particle and Castrol Magnetec oil as carrier fluid throughout the study. MR damper is designed and fabricated, and ...

Semi active control systems are becoming increasingly popular because they offer reliability of passive systems combined with high performance and versatility of active control systems but with low power consumptions. As Magnetorheological (MR) fluids can produce good controllable damping force under application of magnetic field, MR damper can be used as effective element in semiactive vibrati...

Magnetorheological (MR) materials and shear thickening fluids are both smart material and their combination could offer both MR and ST effects. This study looks at the properties and behaviour of magnetorheological shear thickening fluid (MRSTF) in particular whilst applied as a semi-active energy absorber. A device with two forms of varying vibration control has been created and measured. The ...

In this work, a magnetorheological (MR) damper based above-knee prosthesis is design and evaluated based on its performance in swing phase and in stance phase. Initially, a dynamic system model for swing phase of a prosthetic leg incorporating a single-axis knee with ideal MR damper was built. The dynamic properties of the damper are represented with Bingham parametric model. From Bingham model...

Magnetorheological (MR) dampers are one of the most promising new devices for structural vibration reduction. Because of their mechanical simplicity, high dynamic range, low power requirements, large force capacity, and robustness, these devices have been shown to mesh well with application demands and constraints to offer an attractive means of protecting civil infrastructure systems against s...

A new self-powered magnetorheological (MR) damper control system was developed to mitigate cable vibration. The power source of the MR damper is directly harvested from vibration energy through a rotary permanent magnet direct current (DC) generator. The generator itself can also serve as an electromagnetic damper. The proposed smart passive system also incorporates a roller chain and sprocket,...

In this paper, the efficacy of magnetorheological (MR) dampers for seismic response reduction is examined. To investigate the performance of the MR damper, a series of experiments was conducted in which the MR damper is used in conjunction with a recently developed clipped-optimal control strategy to control a three story test structure subjected to a one-dimensional ground excitation. The abil...

Based on theoretical analysis and experiments, this article proposes a new model for a magnetorheological (MR) damper. The proposed model with a smooth and concise form can interpret the bi-viscous and hysteretic behaviors of the MR damper very well. The parameters in the model have definite physical meanings. The bi-viscous and hysteretic behaviors can be characterized by two parameters 0 and ...

Semi-active control systems are becoming more popular because they offer both the reliability of passive systems and the versatility of active control systems without imposing heavy power demands. In particular, it has been found that magnetorheological (MR) fluids can be designed to be very effective vibration control actuators, which use MR fluids to produce controllable damping force. The ob...