Magnetorheological (MR)/Compressible Fluid (CF) Strut Research

Sponsor: U.S. Army Tank-Automotive and Armaments Command
Team Members: University of Maryland, College Park, Materials Modifications, Inc. Lord Corporation

The overall objective of this research program was to examine the feasibility of developing highly compressible MR (CMR) fluids that can be utilized to develop a reduced volume, integrated vehicle strut with controllable damping and spring rate characteristics. The successful combination of MR fluid damper and CF spring technology will provide for unsurpassed suspension performance for military and commercial vehicles over all loading and operational conditions. The vehicle performance provided by this technology will increase the mobility of military vehicles in all terrain conditions while improving vehicle dynamic stability and safety as well. This integrated technology has great commercial potential to the worldwide automotive market.

During this project, three main tasks were undertaken. First, it was necessary to develop and perform validation testing of a compressible MR fluid formulation. These successful tests demonstrated that it was possible to produce an MR fluid that displayed significant compressible behavior. Next, a prototype CF spring/MR damper was designed and fabricated. Shown below, this device was used to measure the performance of the fluid in a pure compressible mode, pure MR mode, and combined CF/MR mode. Finally, a preliminary trade study was performed to show that an integrated CF/MR strut could be designed for use in the Army’s HMMWV.

The testing and analysis conducted under this research program indicates that it is technically feasible to build an integrated compressible fluid spring/magnetorheological fluid damper strut for use in automotive suspensions.