Dynamic response of a tunable phononic crystal under applied mechanical and magnetic loadings

The dynamic response of a tunable phononic crystal consisting of a porous hyperelastic magnetoelastic elastomer subjected to a macroscopic deformation and an external magnetic field is theoretically investigated. Finite deformations and magnetic induction influence phononic characteristics of the periodic structure through geometrical pattern transformation and material properties. A magnetoelastic energy function is proposed to develop constitutive laws considering large deformations and magnetic induction in the periodic structure. Analytical and finite element methods are utilized to compute the dispersion relation and band structure of the phononic crystal for different cases of deformation and magnetic loadings. It is demonstrated that magnetic induction not only controls the band diagram of the structure but also has a strong effect on preferential directions of wave propagation.