Dynamic mechanical properties of MREs under the coupled effect of magnetic field, normal force, and CIP content

Magnetorheological elastomers (MREs) are smart materials whose mechanical properties can be regulated by an external magnetic field. In this study, dynamic shear tests were conducted using a rheometer to investigate the effects of carbonyl iron powder (CIP) content, normal force, and magnetic-field strength on the dynamic mechanical properties of MREs. The results show that under the same test conditions, both the storage and loss moduli increase markedly as the CIP content rises from 40% to 70%. This is because more magnetic particles strengthen the internal load-bearing structure and increase the frictional energy dissipation. When the normal force increases from 2 to 15 N, the moduli also increase. This indicates that moderate compression of the particle structure can reduce performance fluctuation. As the magnetic field increases from 0 to 0.8 T, the moduli increase nonlinearly, although the incremental enhancement gradually diminishes above 0.5 T. Overall, higher CIP content enhances magnetic-field regulation, and a suitable combination of normal force and magnetic field improves the stability of the material response.