Brigley, MikelMR dampers are semi-active devices that are finding success where controllable damping is required. The goal of this work is to determine a suitable design of a six-degree-of-freedom MR isolator for vibration attenuation of a sensor platform and characterize its axial performance through experiments as well as theoretical modeling. This investigation is begun by developing several MR designs and through experiment a single design is chosen for further analysis. Several methods of characterization, including equivalent damping and the complex modulus approach, are used to study the behavior of the MR damper. Several theoretical models for the MR damper are developed: one based upon the Bingham plastic model and the other a nonlinear hysteresis model. The methods used to determine the models parameters are discussed and model results are compared to experimental results.en-USThesisEngineering, Aerospace