Optimal Design of Magnetostrictive Transducers for Power Harvesting from Vibrations

Book chapter, 2011

Methodology is proposed for designing of magnetostrictive electric generator having maximal mean power output for a given amount of active material in a transducer and a prescribed vibration excitation. The methodology is based on dimensional analysis of constitutive linear equations of magnetostriction and numerical solution of constrained optimization problem in transducer’s dimensionless design parameters space by using Sequential Quadratic Programming algorithm. The methodology has been used to design optimal Terfenol-D based transducer for power harvesting from vibrations. It was shown that for steady state operations there exists possibility to choose only 4 new design parameters being the functions of dimensionless parameters of the transducer. Magnetostrictive strain derivative, Young’s modulus and magnetic permeability were determined as functions of magnetic bias and prestress by using experimental data of Terfenol-D. Contour plots and numerical analysis of design parameters show that within the considered concept of magnetostrictive electric generator there exists a set of structural parameters of the transducer that lead to its optimal performance with given amount of active material and prescribed vibration excitation. Examples of solution of optimal design problem demonstrate that for harmonic kinematic excitation with amplitude 0,0002m and frequency 100Hz it is possible to design a magnetostrictive electric generator with 3,2W mean power output having mass of active material 0,01kg.