Leveraging strain localization to improve the performance of magnetoelectric composite cylinders

Abstract

The efficiency of strain-mediated magnetoelectric composites is heavily reliant on the effectiveness of strain transfer between the different constituents. Many analytical and experimental studies have trialed various materials, geometries, and boundary conditions reporting the effect of these attributes on the magnetoelectric response. However, a more sophisticated, but not yet pursued, approach is to investigate the strain distribution in order to discern the factors that are most influential and to provide insight on how these factors should be manipulated to optimize the coupling efficacy. In this study, a mathematical model is developed to observe the radial and tangential strains in a concentric cylinder composite structure consisting of a piezoelectric outer layer bonded with a thin elastic layer to an inner piezomagnetic layer. Results from the study elucidate that the strain distribution behavior was dependent on the mechanical properties of the constituents as well as the bonding condition. Remarkably, analytical results showed that the direct magnetoelectric coefficient can be substantially enhanced, if probing takes place at strategic locations, i.e., leveraging strain localization, on the piezoelectric layer that maximize the difference between the radial displacements giving rise to higher magnetoelectric response.