Mechanical response of magneto-active elastic hemispherical shells

Abstract

We develop a theoretical model that can predict the mechanical behavior of magneto-active elastic hemispherical shells under arbitrary magnetic fields and verify it with experiments and finite element simulations. We use Koiter’s shell theory and consider all components of three basis vectors of an external magnetic field, unlike previous studies that have considered only components in one direction. In addition, we modify the conventional application of the Biot–Savart law to analyze the magnetic field generated by the non-ideal Maxwell coil considering different radii and heights of each winding loop, insulation gaps, magnetostatic effects, and winding imperfections. In experiments, we fabricate magneto-active shells by varying the weight percentage of magnetic fillers and the thickness of the shells and measure the displacement of the pole under various magnetic fields. The theoretical model follows the experimental results more closely than the finite element simulations. Moreover, we find the relation between the pole displacement and the variables and that the pole displacement is independent of the shell thickness. Beyond the simple hemispherical shells, the theoretical model can be used in various application studies, such as drug delivery pumps, soft grippers, and soft robotics.