Innovative Designs for Magneto-Rheological Dampers

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Introduction
The main purpose of this chapter is to introduce the topic of magneto-rheological
(MR) dampers to the reader. Also presented is an explanation of the mechanism
through which MR fluid works. Lastly, the project objectives and the approach
taken to evaluate different MR damper designs are discussed.

1.1 An Overview of Magneto-Rheological Dampers
In recent years, manufacturers have shown an increased interest in MR devices.
For instance, the Lord Corporation has been developing MR fluid and
manufacturing MR truck seat dampers for a number of years now. These seat
dampers are retrofits that replace hydraulic seat dampers that are original
equipment on many large commercial trucks. Lord Corporation’s truck seat
dampers are arguably the most successful commercial MR dampers to date.


Project Objectives
The primary objectives of this research were as follows: (1) to study different
designs that are commonly used for MR dampers; (2) to recommend new designs
that were able to improve the performance of existing MR dampers; and (3) to
provide recommendations for the effective design and fabrication of MR
dampers. To accomplish these goals, several MR dampers were designed, built,
and tested to determine their suitability and performance for specific
applications.

1.3 Approach
The approach used to satisfy the previously stated objectives was to design,
build, and test MR dampers for automotive and gun recoil applications. To
explore the area of MR dampers for gun recoil use, a gun recoil demonstrator
(see Figure 10) was built. A double-ended MR damper was placed behind a
single-shot, bolt-action rifle that was mounted on a ball bearing recoil slide. The
caliber that was chosen for this test apparatus was the 50-caliber Browning
Machine Gun (50BMG) cartridge. This cartridge was chosen because of its high
recoil energy, its availability, and the armed force’s familiarity with weapons of
this caliber.