Particle-resolved description of a soft magnetoelastic actuator

Soft magnetoactive elastomers contain magnetic or magnetizable particles in a soft elastic matrix. They react to external magnetic fields by changes in their overall rheological properties (magnetorheological effect) and by overall deformation (magnetostriction).

Here, we study the latter effect by mesoscopic theory. We analyze how the magnetostrictive response depends on the spatial configuration of the particles inside the elastic matrix, the field orientation, and the matrix material. To this end, we combine analytical linear elasticity theory with numerical evaluation. Several regular and irregular structures that show different types of response were investigated [1]. Interestingly, changing the compressibility of the elastic material can qualitatively modify the overall deformational effect. Adjusting the particle arrangement, we achieve new modes of magnetostriction, e.g. a twist-like deformation [2]. Using particles of different size provides another means of control [3].

Revealing possibilities to adjust the overall deformational response will support the future construction of soft magnetic actuators and robots.