Tailoring magneto-mechanical properties of NdFeB particle-filled soft elastomers

This work investigates the possibilities of tailoring the magneto-mechanical properties of hard (permanent) magnetic NdFeB particle-filled soft magnetorheological elastomers by proposing novel microstructures. Our numerical computations for the mechanical response of various regular and chiral unit cells with a permanently magnetized elliptic inclusion show distinct features depending on the aspect ratio and the orientation of the inclusion. It is observed that the mechanical deformations are selectively preferred at certain directions, which make the magnetic inclusions align themselves along their easy axes, reducing the net magnetic moment. In particular, for the microstructural orientation angle of 30-60 degrees, the simple shear mode is observed to facilitate easy magnetic alignments and thus becomes energetically favorable over the uniaxial tension/compression mode. Moreover, the overall (effective) magnetic coercivity of these composites are found to reduce considerably with a softer elastomeric matrix, which, in turn, facilitate easy particle alignments.