Evaluation of Magnetorheological Elastomers With Oriented Fe–Ga Alloy Flakes for Force Sensing Applications

Abstract

This paper presents the preliminary evaluation results of a magnetorheological elastomer (MRE) patch fabricated by oriented flake-type Fe-Ga alloy (Galfenol) particles bound in a silicone polymer matrix. A force/pressure sensor, based on the Galfenol MRE patch, was developed to verify the advantages of the MRE with magnetically aligned Galfenol flakes. Hall effect sensors embedded in the MRE sensing device detect the change of magnetic flux density due to the deformation of the Galfenol MRE patch induced by an externally applied force with non-magnetic disturbance. The Galfenol flakes are standing up and well aligned to the out-of-plane of the MRE patch using a 1 in diameter permanent magnet, parallel to the applied force direction to improve sensing performance and sensitivity. It was measured at ~105 mV in the sensor response to a thumb pressure, which exhibited five times higher sensing performance compared to that of another MRE patch with the Galfenol flakes aligned to the in-plane direction.