Mechanical behavior of magneto-active elastic shells under an arbitrary magnetic field

We develop a theoretical model of magneto active hemispherical shells and verify it by comparing with experimental results. Magneto-active elastomers which contain the magnetic filler within the elastomeric matrix have been studied due to their features that are soft, wireless and responsive. However, they have been studied only in the uniform magnetic field, although they are magnetized in different directions at each point. To generalize and understand the mechanical behavior induced by magnetic fields, we establish the theoretical model using Hooke's law and Biot-Savart law. Also, we conduct experiments where thin hemispherical shells are fabricated by injection molding with magneto-active elastomer, and evaluated by measuring the displacement of the pole under magnetic fields. Moreover, we vary the weight percent of the NdFeB powder and thickness of the shells to change the magnetic and mechanical properties of the shells. We find that our theoretical model better agrees with the experimental results than the FEM. Beyond the simple hemispherical shells, our theoretical model could be directly used in various applications: capsule drug delivery pumps, soft grippers, and soft robots.