Magnetostrictive Energy Harvesting: Materials and Design Study

In recent years, vibrational energy harvesting has established itself as a promising alternative to the use of batteries for powering microelectromechanical systems for large wireless sensor networks used in aerospace and building infrastructures. This paper has focused on the design and materials used in magnetostrictive cantilever energy harvesters. The study involved using both finite-element modeling to predict the resonance frequencies for different cantilever designs and magnetostrictive materials, followed by experimental measurements for validation. Two different magnetostrictive ribbons were investigated, Fe _100-x Ga _x with four different compositions (x = 17.5 ; 19.5; 21; 28 at.%) and amorphous metallic glass Metglas 2605SC (Fe ₈₁ B _13.5 Si _3.5 C ₂ ). From the modeling, it was determined that the resonance frequency was strongly dependent on the cantilever length, thickness, and density. Changing the cantilever design to a "T" shape was found to decrease the resonance frequency. The experimental results found that the output voltage measured depended on the cantilever dimensions, especially the thickness, the Ga concentration, and the cantilever design. The output voltages for Fe _80.5 Ga _19.5 cantilevers were comparable with the same dimension Metglas cantilevers. The results of the finite-element modeling were validated by good agreement between the computational and experimental resonance frequencies measured.