Innovative Designs for Magneto-Rheological Dampers

Abstract

Magnetorheological dampers, or as they are more commonly called, MR dampers, are being developed for a wide variety of applications where controllable damping is desired. These applications include dampers for automobiles, heavy trucks, bicycles, prosthetic limbs, gun recoil systems, and possibly others.

This thesis first introduces MR technology through a discussion of MR fluid and then by giving a broad overview of MR devices that are being developed. After giving the reader an understanding of MR technology and devices, MR damper basics are presented. This section includes a discussion of MR damper types, mathematical fundamentals, and an approach to magnetic circuit design.

With the necessary background information covered, MR dampers for automotive use are then discussed. Specifically, designs for MR dampers that were built for a Mercedes ML-430 and for a Ford Expedition are presented along with their respective test results. These test results are presented and compared with the original equipment hydraulic dampers.

After discussing automotive MR dampers, designs for gun recoil applications are presented. Specifically, two different MR damper designs are discussed along with live-fire test results for the first damper.

Finally, two hybrid dampers that were based on a modified adjustable hydraulic damper are presented. These hybrid dampers, if pursued further, may develop into controllable replacements for large hydraulic dampers such as those installed on large vehicles and field Howitzers. In conclusion, recommendations are made for materials as well as for seal selection and other design aspects.