Unconventional deformation and sound absorption properties of anisotropic magnetorheological elastomers

摘要

The mechanical properties and applications of magnetorheological elastomer films strengthened by NdFeB particles (NMRE) were investigated in this work. The NMRE film exhibited anisotropic magnetism and diverse magnetic controllability because of its large remanence and coercivity. The NMRE film was magnetized perpendicular to the surface and possessed a unique residue magnetic field. The edge of the NMRE film performed a relatively strong magnetic field, which can reach 9-10 mT, while the magnetic field in center was only 2-3 mT. This magnetic unevenness showed huge influences on the deformation of the NMRE film. When the NMRE film with fixed edge was close to a magnet, the center of the NMRE film was attracted by the magnet more observably even though the resultant force on the NMRE film was repulsive force. Based on the above unconventional deformation principle, the NMRE sound absorbers with magnetic direction-dependent tunability range were developed. The peak sound absorption frequency of NMRE sound absorbers shifted 880 Hz under an opposite magnetic field and 230 Hz under a magnetic field with the same direction. Therefore, the NMRE sound absorbers exhibit multi-level tunability and the NMRE is of great potential in complex magnetic control.