Diversifying temporal responses of magnetoactive elastomers

Magnetoactive elastomers(MAEs) are able to deform significantly in response to the application of magnetic fields. Usually, a magnetic field which is harmonic in time usually results in a harmonic mechanical response of the MAEs. To render MAEs with the ability of responding or deforming diversely or anharmonically in time, in this work, we propose a hybrid MAE which is based on a rubber matrix embedded with both soft iron particles and hard NdFeB-alloy particles. Firstly, based on the principle of minimum free energy, we establish a theoretical model to study magnetomechanical behaviors of the proposed hybrid MAEs. Then, through both theoretical and experimental studies, we show that the response of a hybrid MAE sample to the applied magnetic field is usually complex, i.e. the deformation induced by a harmonic magnetic field in time is anharmonic. At last, the effect of two main factors, the state of magnetization and the amplitude of the applied magnetic field, is studied both experimentally and theoretically. This work provides a new idea of diversifying the temporal response of MAEs to the application of harmonic magnetic fields (harmonic in time). The hybrid MAEs may serve as a complement to the recently proposed 3D-printed hard MAEs which are able to deform inhomogeneously in space in response to a uniform magnetic field.