Gm Global Technolgoy Operations, Inc.

Min Mao

Nancy L Johnson

Alan L Browne

Norman Mark Wereley

Wei Hu

Young Tai Choi

Chandra S Namuduri

John C Ulicny

A method of designing a magnetorheological (MR) fluid energy absorbing damper is provided that uses hydromechanical analysis with lumped parameters to allow a determination as to whether a potential damper design will provide predetermined characteristics, such as a desired dynamic force range and maximum piston velocity, with a selected MR fluid and yield stress and preferably meeting predetermined geometric limitations.

Method of designing magnetorheological fluid energy absorbing device using hydromechanical analysis

An energy absorbing device is provided that includes a damper assembly having inner and outer concentric tubes and a piston movable within the inner tube. The damper assembly is configured to form bi-fold valve-type cavities to operatively connect an inner chamber of the inner tube with an outer chamber formed between the inner and outer tubes. A magnetorheological fluid fills the chambers and the bi-fold valve-type cavities. The magnetorheological fluid preferably contains coated magnetic particles at about 10 to 60 percent by volume. Electrical coils adjacent the bi-fold valves are selectively energizable to such that the energy absorbing device provides a tunable damping force, preferably over the entire range of velocities of the piston, especially in automotive applications.

Bi-fold valve-type magnetorheological fluid energy absorbing device

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College Park, MD, United States of America

Min Mao