Magnetically tunable longitudinal wave band gaps in hard-magnetic soft laminates

Hard-magnetic soft materials belong to the class of active materials that undergo finite deformation and alter their material properties when subjected to magnetic loading. Because of these characteristics, the periodic composites/phononic crystals made up of hard-magnetic soft materials can be promising candidates for filtering acoustic/elastic waves across frequency bands that can be tuned in real-time by applying external magnetic loading. In this work, the nonlinear finite deformation, and the superimposed small-amplitude longitudinal elastic wave band gap characteristics of an infinite periodic hard-magnetic soft material laminate under the applied magnetic flux density are investigated. The compressible Gent hyperelastic model in conjunction with the ideal hard-magnetic soft material model is used for characterizing the constitutive response of laminate phases. The band structure of an infinite periodic hard-magnetic soft material laminate subjected to magnetic load is extracted by developing an in-house finite element model with Bloch’s periodic boundary conditions. The influence of some factors such as material properties, volume fractions, and applied magnetic flux density on the tunability of the longitudinal wave band gaps is explored. The numerical findings demonstrate that the width and the position of band gaps can be tuned by varying the applied magnetic flux density. The volume fraction and the material properties of laminate phases also play significant roles in the generation of band gaps. The numerical results and inferences reported here should provide the guidelines for designing futuristic remotely and actively controlled wave-manipulating devices.