Magnetorheological elastomer (mre) apparatuses, methods, and systems, including bushings for vibrational damping or isolation

Abstract

An isolator designed through the inclusion of a magnetorheological elastomer (MRE) along and at or near an electromagnetic coil. A variety of factors can be balanced to produce an isolator that takes advantage of the radially axial coil. One non-limiting embodiment of the design uses a two-part coil bobbin geometry; wherein the axial center of the bobbin is a nonmagnetic material which allows passage of the magnetic field, while the end pieces are made of a high permeability material that limits the stray magnetic field and improves the magnetic flux density through the MRE by providing a pathway of least magnetic reluctance. The MRE changes stiffness and damping properties in response to the strength of the magnetic field, which can be controlled by changing the current through the electromagnetic coil. Feedback and feedforward control systems can allow for real time adaptation by the isolator in response to changing external stimuli. The isolator is useful for a variety of uses. Non-limiting examples are for reducing whole body vibrations for operators of trucks and heavy machinery, as well as for creating greater comfort for patients in ambulance gurneys and passengers in airplane seats.